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This application is a continuation of application Ser. No. 07/244/729, filed on 9/15/88 now abandoned. BACKGROUND OF THE INVENTION Belt drive systems are frequently used, particularly for driving auxiliary units associated to an internal combustion engine. For providing a tension in the belt of such a belt drive system, a tensioning roller acts onto the belt. The tensioning roller is under the action of biasing spring means. For damping the tensioning roller movement, a damper unit is provided. In many cases, the tension of the drive belt is dependent on the running direction of the drive belt. In a first or normal driving direction, the belt tension is sufficient for maintaining the belt in driving engagement with respective belt pulleys. If the driving direction is reversed, a reduction of the belt tension occurs, and this reduced tension may result in a disengagement of the belt and the respective pulleys. Normal damping of the tensioning roller cannot prevent this disengagement of the belt and the belt pulleys if a reversal of the driving direction occurs. A reversal of the driving direction is particularly to be expected with internal combustion engines, and more particularly with diesel engines, when the operation is interrupted. OBJECT OF THE INVENTION It is an object of the present invention to provide a belt drive system in which the danger of disengagement between the belt and the belt pulleys is suppressed even on occurrence of a reversal of the driving direction. SUMMARY OF THE INVENTION A belt drive system comprises at least two belt pulleys. A belt member drivingly interconnects said belt pulleys. A tensioning member acts onto a belt section of said belt member between said pulleys. Said tensioning member is biased against said belt section along a tensioning member movement path such as to provide a belt tension. Said belt tension is responsive to the driving direction of said belt drive system. A higher tension of said belt member occurs in a normal driving direction of said belt drive system and a lower belt tension occurs in a reverse driving direction of said belt drive system. A damping unit acts onto said tensioning member for damping the movement of said tensioning member along said tensioning member movement path. Said damping unit comprises two damper components movable with respect to each other in response to the movement of said tensioning member along said tensioning member movement path. Damping means provide a damping force resisting to relative movement of said damper components. Damping force control means are provided for varying said damping force. Said damping force control means are controlled such that said damping force is increased in response to the occurrence of at least one of the following situations: (a) reverse driving direction of the belt drive system occurs; (b) operational conditions occur under which occurrence of the reverse driving direction of the belt drive system is expectable. The damping force may be increased such that the movement of the tensioning member along its movement path is completely locked. If the movement of the damper components is completely locked the tensioning roller cannot further move against the biasing force, so that the tension of the belt member is maintained even on reversal of the driving direction. If, for example, the belt drive system is used for driving an auxiliary unit, like an electric generator or a water pump or a ventilator of a diesel engine, the damper may be locked in response to the interruption of the electrical ignition circuit by an ignition lock. If the ignition circuit is interrupted, the diesel engine comes to a standstill, and in this situation there is a likelihood of disengagement of the belt member and the belt pulleys due to the reduced tension in the belt pulley. As however, as stated above, the damper is locked in response to the interruption of the ignition circuit, the risk of such disengagement is suppressed. According to a preferred embodiment of the invention, a fluid-operated damping unit is used. Such a fluid-operated damping unit comprises two damper components movable with respect to each other in response to the movement of said tensioning member along said tensioning member movement path. Said damper components define at least two fluid spaces, the volume ratio of which is variable in response to relative movement of said damper components. Said fluid spaces are interconnected by fluid passage means allowing a fluid flow between said fluid spaces in opposite directions respectively in response to the direction of movement of said tensioning member along said tensioning member movement path. Fluid passage control means are provided for reducing the flow cross section of said fluid passage means for at least that flow direction which corresponds to the direction of movement of said tensioning member resulting in a reduced tension of said belt member. Said fluid passage control means are controlled such that said flow cross section is reduced in response to the occurrence of at least one of the following situations: (a) reverse driving direction of the belt drive system occurs; (b) operational conditions occur under which occurrence of the reverse driving direction of the belt drive system is expectable. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in greater detail hereinafter with reference to embodiments shown in the accompanying drawings, in which: FIG. 1 shows a first embodiment of a damping unit; FIG. 2 shows a second embodiment of a damping unit; FIG. 3 shows a third embodiment of a damping unit; and FIG. 4 shows a belt drive system using a damping unit as illustrated in one of FIGS. 1, 2, 3. DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 4, a diesel engine is designated by A. This diesel engine has a belt pulley B on an output shaft C. An auxiliary unit, like a water pump D, is fastened to the diesel engine A. This auxiliary unit D comprises a further belt pulley E which is connected with a rotor of the auxiliary unit by a shaft F. A belt member G interconnects the belt pulleys B and E. A tensioning roller H acts onto an unsupported intermediate section of the belt member G extending between the belt pulleys E and B. This tensioning roller H is mounted on a rocking lever I. This rocking lever I is pivotally mounted in a pivot K. A biasing spring unit L acts onto the rocking lever I such as to bias the tensioning roller H against a belt member G. A damping unit M also acts onto the rocking lever I. The damping unit M is supported by a pivot means N fastened to a diesel engine A and is connected by pivot means O to the rocking lever I. The normal driving direction of the belt member G is indicated by an arrow P. In an operation corresponding to the arrow P, the belt member G is subjected to a tension which is sufficient to prohibit disengagement of the belt member G from the pulleys. If the driving direction of the belt member G is reversed, a reduction of the tension in the belt member G occurs. This may be a result of the specific arrangement of the tensioning roller H on the rocking lever I and the angle included between the rocking lever I and the unsupported section of the belt member G. The damping unit M is used for damping the tensioning roller H along a movement path R. In normal operation according to arrow P, the tension of the belt member G is primarily due to the spring force of the biasing spring unit L. This tension is however increased by a torque exerted onto the rocking lever I as a result of the engagement of the belt member G and the tensioning roller H. When the driving direction is reversed, this torque does not further occur and the tension of the belt member G is only obtained by the spring force of the biasing spring unit L. So the tension of the belt member G is reduced with the result that the belt member G can disengage from one or both of the belt pulleys B and E. This danger is however eliminated by the specific construction of the damping unit M. While, in normal operation, the damper unit M damps the movement of the tensioning roller H along the movement path R, and more particularly, the movement in the direction R 1 , on reversal of the driving direction, the damping unit L is locked. So the tension roller H is prevented from escaping in the direction of arrow R 1 . As a result thereof, the tension in the belt member G is maintained even on reversal of the driving direction. A direction sensing unit S is attached to the belt pulley B. This direct sensing unit delivers by line T a direction reversal signal to the damping unit M when reversal of the direction occurs. By this direction reversal signal, damping unit M is locked. Alternatively, a control line U connects an ignition lock V with the damping unit M, so that, on interruption of the ignition circuit W, the damping unit M is locked. If, as a result of the interruption of the ignition circuit W, the diesel engine A rotates in a direction reverse to the normal operational direction, the damping unit M is already locked and no reduction of tension can occur in the belt member G. Various embodiments of the damping unit are shown in FIGS. 1, 2, 3. In the embodiment of FIG. 1, the damping unit M comprises a container 11. The container 11 defines a cavity 12 and a compensation chamber 13. The cavity 12 is subdivided by a piston unit 18 into two working chambers 12a and 12b. The piston unit 18 is fastened to a piston rod 19 axially movable through a lower end wall 40 of the container 11. The piston unit 18 is provided with a damping valve means 41. A valve plate 14 is provided within the container 11 and comprises additional damping valve means 42. A separation wall 15 is provided above the valve plate 14. The container 11 is filled up to the level 39 with a liquid. The compensation chamber 13 contains a volume of gas. The compensation chamber 13 is defined by an axial extension 43 of the container 11. The compensation chamber 13 is closed by an upper end wall 16. A control opening 21 is provided in the separating wall 15. This control opening 21 is selectively opened or closed by a frustro-conical control member 20. The control member 20 is fixed to the control shaft 17 which sealingly extends through the end wall 16. The control shaft 17 is electromagnetically operated by an actuation circuit 45. The container 11 is connected by pivot means N to the diesel engine A. In a normal operation of the drive belt system corresponding to the direction P of FIG. 4, the control opening 21 is open. Inward movement of the piston rod 19 is damped by the flow resistance of the damping valve means 42, no essential flow resistance occurring in the piston valve means 41, so that the working chamber 12b is refilled across the piston valve means 41. The volume of the piston rod 18 within the cavity 12 is increased on upward movement of the piston rod 19, so that a liquid is driven out through the control opening 21 of the separation wall 15. On downward movement of the piston rod 19, a small flow resistance occurs in the piston valve means 41 and a small flow resistance also occurs in the damping valve means 42, so that outward movement of the piston rod 19 is not substantially damped. It is however possible to damp also outward movement of the piston rod 19 by a corresponding design of the piston valve means 41 such that the increased flow resistance resists the flow of the liquid from the working chamber 12b to the working chamber 12a. If the locking signal is sent to the damping unit M, the control member 20 closes the control opening 21. By this, inward movement of the piston rod 19 is locked because no escape of liquid can occur from the working chamber 12a to the compensation chamber 13 on upward movement of the piston rod 19. So the belt member G remains under sufficient tension. The embodiment of FIG. 3 is similar to the embodiment of FIG. 1. Only the differences over FIG. 1 are described. The separation wall 35 is provided with a control opening 33. The frustro-conical control member 20 cooperates with the control opening 33. The control member 20 is fixed by a control shaft 40 to a guide plate 46. The guide plate 46 is biased in upward direction by a helical compression spring 36 supported on the separation wall 35. So the control member 20 is biased towards its closing position. An operating rod 34 extends through the extension 43 of the container 11 in a direction perpendicular to the axis of the piston rod 19. A conical cam member 37 is provided on the operating rod 34 and is biased leftwards by a helical compression spring 38. The conical cam member 37 engages a spherical counter-cam member 32 provided on the guiding member 46. The helical compression spring 38 is stronger than the helical compression spring 36, so that the control member 20 is maintained in its open position with respect to the control opening 33 if no external force is exerted onto the operating rod 34. If the control rod 34 is moved to the right in FIG. 3 by mechanical or electromagnetical actuation means, the control member 20 is moved upward by the helical compression spring 36 and the conical opening 33 is closed. The operation of the embodiment of FIG. 3 is identical with the operation of the embodiement of FIG. 1, except for the actuation of the control member 20. The operating rod 34 extends along the axis of the pivot means N, so that actuation of this operating rod 34 is easy in spite of the mobility of the damping unit with respect to its support, i.e. the diesel engine A. In the embodiment of FIG. 2, the piston rod 19 is provided with a central bore 31. A control rod 22 is slidably housed within the central bore 31. A locking sleeve 23 is provided within the central bore 31. The locking sleeve 23 is provided with transversal bores 47 which extend into the circumferential annular space 30. The piston rod 19 is provided with a bore 25. Damping liquid can flow through said bore 25 from the annular space 30 into the upper working chamber 12b which is adjacent to the compression space 13. The sleeve 23 is sealed by sealing rings 28 within the piston rod 19. The sleeve 23 is supported towards the working chamber 12b by a further sealing ring 28. The piston unit 18 comprises damping valve means 26 and is secured by an abutment ring 24. The abutment ring 24 is fastened to the piston rod 19 by a slit ring 29. A downward movement of the piston rod 19 is damped by the flow resistance of the piston valve means. Upward movement of the piston rod 19 is substantially not damped, but can be damped also. On occurrence of the blocking signal to the control rod 22, the control rod 22 is moved downward with respect to the piston rod 19, so that the downward movement of the piston rod 19 is damped with higher damping force or even locked because the transversal bores 47 are closed. The control rod 22 may be actuated either mechanically or electrically. While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles. The reference numerals in the claims are only used for facilitating the understanding and are by no means restrictive.
In a belt drive, a tensioning roller acts onto a section of a belt. The tensioning roller is biased along a tensioning roller movement path such as to provide a tension of the belt. The tension of the belt is responsive to the driving direction of the belt. A higher tension occurs in a normal driving direction of the belt, and a lower tension occurs in a reverse driving direction of the belt. In the reverse driving direction of the belt there is a risk of disengagement between the belt and respective belt pulleys. A damper is provided for damping the movement of the tensioning roller along the tensioning roller movement path. In order to prevent disengagement of the belt and the respective belt pulleys, the damper is locked when a reverse driving direction occurs and/or when operational conditions occur under which there is a likelihood of the reverse driving direction to occur.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "This application is a continuation of application Ser.", "No. 07/244/729, filed on 9/15/88 now abandoned.", "BACKGROUND OF THE INVENTION Belt drive systems are frequently used, particularly for driving auxiliary units associated to an internal combustion engine.", "For providing a tension in the belt of such a belt drive system, a tensioning roller acts onto the belt.", "The tensioning roller is under the action of biasing spring means.", "For damping the tensioning roller movement, a damper unit is provided.", "In many cases, the tension of the drive belt is dependent on the running direction of the drive belt.", "In a first or normal driving direction, the belt tension is sufficient for maintaining the belt in driving engagement with respective belt pulleys.", "If the driving direction is reversed, a reduction of the belt tension occurs, and this reduced tension may result in a disengagement of the belt and the respective pulleys.", "Normal damping of the tensioning roller cannot prevent this disengagement of the belt and the belt pulleys if a reversal of the driving direction occurs.", "A reversal of the driving direction is particularly to be expected with internal combustion engines, and more particularly with diesel engines, when the operation is interrupted.", "OBJECT OF THE INVENTION It is an object of the present invention to provide a belt drive system in which the danger of disengagement between the belt and the belt pulleys is suppressed even on occurrence of a reversal of the driving direction.", "SUMMARY OF THE INVENTION A belt drive system comprises at least two belt pulleys.", "A belt member drivingly interconnects said belt pulleys.", "A tensioning member acts onto a belt section of said belt member between said pulleys.", "Said tensioning member is biased against said belt section along a tensioning member movement path such as to provide a belt tension.", "Said belt tension is responsive to the driving direction of said belt drive system.", "A higher tension of said belt member occurs in a normal driving direction of said belt drive system and a lower belt tension occurs in a reverse driving direction of said belt drive system.", "A damping unit acts onto said tensioning member for damping the movement of said tensioning member along said tensioning member movement path.", "Said damping unit comprises two damper components movable with respect to each other in response to the movement of said tensioning member along said tensioning member movement path.", "Damping means provide a damping force resisting to relative movement of said damper components.", "Damping force control means are provided for varying said damping force.", "Said damping force control means are controlled such that said damping force is increased in response to the occurrence of at least one of the following situations: (a) reverse driving direction of the belt drive system occurs;", "(b) operational conditions occur under which occurrence of the reverse driving direction of the belt drive system is expectable.", "The damping force may be increased such that the movement of the tensioning member along its movement path is completely locked.", "If the movement of the damper components is completely locked the tensioning roller cannot further move against the biasing force, so that the tension of the belt member is maintained even on reversal of the driving direction.", "If, for example, the belt drive system is used for driving an auxiliary unit, like an electric generator or a water pump or a ventilator of a diesel engine, the damper may be locked in response to the interruption of the electrical ignition circuit by an ignition lock.", "If the ignition circuit is interrupted, the diesel engine comes to a standstill, and in this situation there is a likelihood of disengagement of the belt member and the belt pulleys due to the reduced tension in the belt pulley.", "As however, as stated above, the damper is locked in response to the interruption of the ignition circuit, the risk of such disengagement is suppressed.", "According to a preferred embodiment of the invention, a fluid-operated damping unit is used.", "Such a fluid-operated damping unit comprises two damper components movable with respect to each other in response to the movement of said tensioning member along said tensioning member movement path.", "Said damper components define at least two fluid spaces, the volume ratio of which is variable in response to relative movement of said damper components.", "Said fluid spaces are interconnected by fluid passage means allowing a fluid flow between said fluid spaces in opposite directions respectively in response to the direction of movement of said tensioning member along said tensioning member movement path.", "Fluid passage control means are provided for reducing the flow cross section of said fluid passage means for at least that flow direction which corresponds to the direction of movement of said tensioning member resulting in a reduced tension of said belt member.", "Said fluid passage control means are controlled such that said flow cross section is reduced in response to the occurrence of at least one of the following situations: (a) reverse driving direction of the belt drive system occurs;", "(b) operational conditions occur under which occurrence of the reverse driving direction of the belt drive system is expectable.", "The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure.", "For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.", "BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in greater detail hereinafter with reference to embodiments shown in the accompanying drawings, in which: FIG. 1 shows a first embodiment of a damping unit;", "FIG. 2 shows a second embodiment of a damping unit;", "FIG. 3 shows a third embodiment of a damping unit;", "and FIG. 4 shows a belt drive system using a damping unit as illustrated in one of FIGS. 1, 2, 3.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 4, a diesel engine is designated by A. This diesel engine has a belt pulley B on an output shaft C. An auxiliary unit, like a water pump D, is fastened to the diesel engine A. This auxiliary unit D comprises a further belt pulley E which is connected with a rotor of the auxiliary unit by a shaft F. A belt member G interconnects the belt pulleys B and E. A tensioning roller H acts onto an unsupported intermediate section of the belt member G extending between the belt pulleys E and B. This tensioning roller H is mounted on a rocking lever I. This rocking lever I is pivotally mounted in a pivot K. A biasing spring unit L acts onto the rocking lever I such as to bias the tensioning roller H against a belt member G. A damping unit M also acts onto the rocking lever I. The damping unit M is supported by a pivot means N fastened to a diesel engine A and is connected by pivot means O to the rocking lever I. The normal driving direction of the belt member G is indicated by an arrow P. In an operation corresponding to the arrow P, the belt member G is subjected to a tension which is sufficient to prohibit disengagement of the belt member G from the pulleys.", "If the driving direction of the belt member G is reversed, a reduction of the tension in the belt member G occurs.", "This may be a result of the specific arrangement of the tensioning roller H on the rocking lever I and the angle included between the rocking lever I and the unsupported section of the belt member G. The damping unit M is used for damping the tensioning roller H along a movement path R. In normal operation according to arrow P, the tension of the belt member G is primarily due to the spring force of the biasing spring unit L. This tension is however increased by a torque exerted onto the rocking lever I as a result of the engagement of the belt member G and the tensioning roller H. When the driving direction is reversed, this torque does not further occur and the tension of the belt member G is only obtained by the spring force of the biasing spring unit L. So the tension of the belt member G is reduced with the result that the belt member G can disengage from one or both of the belt pulleys B and E. This danger is however eliminated by the specific construction of the damping unit M. While, in normal operation, the damper unit M damps the movement of the tensioning roller H along the movement path R, and more particularly, the movement in the direction R 1 , on reversal of the driving direction, the damping unit L is locked.", "So the tension roller H is prevented from escaping in the direction of arrow R 1 .", "As a result thereof, the tension in the belt member G is maintained even on reversal of the driving direction.", "A direction sensing unit S is attached to the belt pulley B. This direct sensing unit delivers by line T a direction reversal signal to the damping unit M when reversal of the direction occurs.", "By this direction reversal signal, damping unit M is locked.", "Alternatively, a control line U connects an ignition lock V with the damping unit M, so that, on interruption of the ignition circuit W, the damping unit M is locked.", "If, as a result of the interruption of the ignition circuit W, the diesel engine A rotates in a direction reverse to the normal operational direction, the damping unit M is already locked and no reduction of tension can occur in the belt member G. Various embodiments of the damping unit are shown in FIGS. 1, 2, 3.", "In the embodiment of FIG. 1, the damping unit M comprises a container 11.", "The container 11 defines a cavity 12 and a compensation chamber 13.", "The cavity 12 is subdivided by a piston unit 18 into two working chambers 12a and 12b.", "The piston unit 18 is fastened to a piston rod 19 axially movable through a lower end wall 40 of the container 11.", "The piston unit 18 is provided with a damping valve means 41.", "A valve plate 14 is provided within the container 11 and comprises additional damping valve means 42.", "A separation wall 15 is provided above the valve plate 14.", "The container 11 is filled up to the level 39 with a liquid.", "The compensation chamber 13 contains a volume of gas.", "The compensation chamber 13 is defined by an axial extension 43 of the container 11.", "The compensation chamber 13 is closed by an upper end wall 16.", "A control opening 21 is provided in the separating wall 15.", "This control opening 21 is selectively opened or closed by a frustro-conical control member 20.", "The control member 20 is fixed to the control shaft 17 which sealingly extends through the end wall 16.", "The control shaft 17 is electromagnetically operated by an actuation circuit 45.", "The container 11 is connected by pivot means N to the diesel engine A. In a normal operation of the drive belt system corresponding to the direction P of FIG. 4, the control opening 21 is open.", "Inward movement of the piston rod 19 is damped by the flow resistance of the damping valve means 42, no essential flow resistance occurring in the piston valve means 41, so that the working chamber 12b is refilled across the piston valve means 41.", "The volume of the piston rod 18 within the cavity 12 is increased on upward movement of the piston rod 19, so that a liquid is driven out through the control opening 21 of the separation wall 15.", "On downward movement of the piston rod 19, a small flow resistance occurs in the piston valve means 41 and a small flow resistance also occurs in the damping valve means 42, so that outward movement of the piston rod 19 is not substantially damped.", "It is however possible to damp also outward movement of the piston rod 19 by a corresponding design of the piston valve means 41 such that the increased flow resistance resists the flow of the liquid from the working chamber 12b to the working chamber 12a.", "If the locking signal is sent to the damping unit M, the control member 20 closes the control opening 21.", "By this, inward movement of the piston rod 19 is locked because no escape of liquid can occur from the working chamber 12a to the compensation chamber 13 on upward movement of the piston rod 19.", "So the belt member G remains under sufficient tension.", "The embodiment of FIG. 3 is similar to the embodiment of FIG. 1. Only the differences over FIG. 1 are described.", "The separation wall 35 is provided with a control opening 33.", "The frustro-conical control member 20 cooperates with the control opening 33.", "The control member 20 is fixed by a control shaft 40 to a guide plate 46.", "The guide plate 46 is biased in upward direction by a helical compression spring 36 supported on the separation wall 35.", "So the control member 20 is biased towards its closing position.", "An operating rod 34 extends through the extension 43 of the container 11 in a direction perpendicular to the axis of the piston rod 19.", "A conical cam member 37 is provided on the operating rod 34 and is biased leftwards by a helical compression spring 38.", "The conical cam member 37 engages a spherical counter-cam member 32 provided on the guiding member 46.", "The helical compression spring 38 is stronger than the helical compression spring 36, so that the control member 20 is maintained in its open position with respect to the control opening 33 if no external force is exerted onto the operating rod 34.", "If the control rod 34 is moved to the right in FIG. 3 by mechanical or electromagnetical actuation means, the control member 20 is moved upward by the helical compression spring 36 and the conical opening 33 is closed.", "The operation of the embodiment of FIG. 3 is identical with the operation of the embodiement of FIG. 1, except for the actuation of the control member 20.", "The operating rod 34 extends along the axis of the pivot means N, so that actuation of this operating rod 34 is easy in spite of the mobility of the damping unit with respect to its support, i.e. the diesel engine A. In the embodiment of FIG. 2, the piston rod 19 is provided with a central bore 31.", "A control rod 22 is slidably housed within the central bore 31.", "A locking sleeve 23 is provided within the central bore 31.", "The locking sleeve 23 is provided with transversal bores 47 which extend into the circumferential annular space 30.", "The piston rod 19 is provided with a bore 25.", "Damping liquid can flow through said bore 25 from the annular space 30 into the upper working chamber 12b which is adjacent to the compression space 13.", "The sleeve 23 is sealed by sealing rings 28 within the piston rod 19.", "The sleeve 23 is supported towards the working chamber 12b by a further sealing ring 28.", "The piston unit 18 comprises damping valve means 26 and is secured by an abutment ring 24.", "The abutment ring 24 is fastened to the piston rod 19 by a slit ring 29.", "A downward movement of the piston rod 19 is damped by the flow resistance of the piston valve means.", "Upward movement of the piston rod 19 is substantially not damped, but can be damped also.", "On occurrence of the blocking signal to the control rod 22, the control rod 22 is moved downward with respect to the piston rod 19, so that the downward movement of the piston rod 19 is damped with higher damping force or even locked because the transversal bores 47 are closed.", "The control rod 22 may be actuated either mechanically or electrically.", "While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.", "The reference numerals in the claims are only used for facilitating the understanding and are by no means restrictive." ]
This application is a division of application Ser. No. 09/133,999 filed Aug. 13, 1998 now U.S. Pat. No. 5,955,751. FIELD OF THE INVENTION This invention relates to programmable integrated circuits (for example, field programmable gate arrays or "FPGAs") employing antifuses. BACKGROUND AND RELATED PRIOR ART A field programmable gate array is a versatile integrated circuit chip, the internal circuitry of which may be configured by an individual user to realize a user-specific circuit. To configure a field programmable gate array, the user configures an on-chip interconnect structure of the field programmable gate array so that selected inputs and selected outputs of selected on-chip logic components are connected together in such a way that the resulting circuit is the user-specific circuit desired by the user. For additional background on antifuse-based field programmable gate array structures, the reader is referred to: U.S. Pat. Nos. 5,495,181, 5,424,655, 5,122,685, 5,055,718, 4,873,459, 5,502,315, 5,362,676, 5,557,136, 5,308,795 and 5,233,217; U.S. patent application Ser. No. 08/667,702 now U.S. Pat. No. 5,825,201 issued on Oct. 10, 1998 entitled "ramming Architecture For A Programmable Integrated Circuit Employing Antifuses" by Paige A. Kolze, filed Jun. 21, 1996; the 1996/97 QuickLogic Data Book; the 1996 Actel FPGA Data Book and Design Guide; and the book entitled "Field-Programmable Gate Arrays" by Stephen Brown et al., Kluwer Academic Publishers (1992) (the subject matter of these documents is incorporated herein by reference). FIG. 1 (Prior Art) is a top-down diagram of a first conventional field programmable gate array 1 (for example, the QL 16X24 QuickLogic field programmable gate array in the pASIC1 family). Field programmable gate array (FPGA) 1 includes a plurality of interface cells 2, a plurality of logic modules 3 arranged in rows and columns, and a programmable interconnect structure 4 employing antifuses. The programmable interconnect is disposed in spaces between the rows and columns of logic modules. FIG. 2 (Prior Art) is a top-down diagram of a matrix of locations. Many of the antifuses of the programmable interconnect structure of FPGA 1 are disposed in such a matrix. The rows of locations are labeled with row designators RA, RB, RC and so forth. The columns of locations are labeled with column designators C1, C2, C3 and so forth. For each column, there is a vertically extending column conductor (not shown) that extends underneath the locations of its column. For each row, there is a horizontally extending row conductor (not shown) that extends underneath the locations of its row. The row conductors extend in a plane over the plane of the column conductors. Antifuses are disposed at the locations illustrated in FIG. 2 where the row conductors cross the column conductors. For example, to couple vertically extending column conductor C3 to horizontally extending row conductor R4, an antifuse disposed at location C3/R4 would be programmed. The lateral distance DIS between respective antifuses in a row and between respective antifuses in a column is the minimum lateral spacing between antifuses on the FPGA. No two antifuses of the FPGA are separated by a lateral distance smaller than lateral distance DIS. In FPGA 1, some of the matrix locations are not populated with antifuses. Some of the conductors are made wider to reduce conductor resistance to speed the propagation of signals through the conductor. Distances greater than distance DIS separate some of the rows and/or columns to accommodate wider conductors. In this first conventional FPGA: 1) the antifuses are conductive plug-type antifuses (for more details on conductive plug-type antifuses, see the description below); 2) none of the antifuses has an associated programmable material corner under a metal conductor within lateral distance DIS of the conductive plug of the antifuse (for more details on what such a programmable material corner is, see the description below); and 3) approximately 20 percent of the antifuses have programmable material edges under a metal conductor within lateral distance DIS of the conductive plug of the antifuse (for more details on what such a programmable material edge is, see the description below). FIG. 3 (Prior Art) is a top-down diagram of two antifuses 5 and 6 of a second conventional FPGA (for example, the QL2007 QuickLogic FPGA in the pASIC2 family). To increase packing density in this second conventional FPGA, the spaces between logic modules of the first conventional FPGA are substantially eliminated in the center portion of the integrated circuit and the programmable interconnect structure is disposed in layers above the logic modules. A matrix of antifuses is disposed over each respective logic module. For example, an antifuse 5 is disposed at location RB/C1 and an antifuse 6 is disposed at location RB/C3. There is no antifuse at location RB/C2. An inter-metal layer insulator covers the underlying column conductors and separates the column conductors from the overlaying row conductor. If programmed, antifuse 5 would couple vertically extending column conductor 7 to overlaying horizontally extending row conductor 8. If programmed, antifuse 6 would couple vertically extending column conductor 9 to horizontally extending row conductor 8. In the second conventional FPGA, the antifuses are also conductive plug-type antifuses. Each conductive plug-type antifuse includes a conductive plug and a layer of a programmable material disposed over the conductive plug between the top of the plug and the bottom of the overlaying row conductor. The conductive plug is disposed in an opening in the inter-metal layer insulator. When programmed, a conductive filament forms through the layer of programmable material to couple the conductive plug to the overlaying row conductor. For additional background information on conductive plug-type antifuse structures and how to make them, see U.S. Pat. Nos. 5,557,136, 5,308,795 and 5,233,217, and the U.S. patent application No. 09/133,998, now allowed entitled "Metal-to-Metal Antifuse Having Improved Barrier Layer", by Rajiv Jain et al., filed Aug. 13, 1998 (the subject matter of these patents and this patent application is incorporated herein by reference). FIG. 4 (Prior Art) is a cross-sectional diagram taken along sectional line SS' of FIG. 3. Layer 10 is a layer of insulation (for example, silicon dioxide). The antifuses are disposed in layers above the substrate such that layer 10 insulates the antifuse and programmable interconnect layers from underlying logic module transistors in the substrate. Column conductor 7 and column conductor 9 each includes a bottom barrier layer (for example, TiW or TiN), a relatively thick layer involving aluminum, and a top barrier layer (for example, TiW or TiN). Conductive plugs 5P and 6P of antifuses 5 and 6 are disposed in openings in inter-metal layer insulation 11. The center axis 5PA of conductive plug 5P is located at location RB/C I and the center axis 6PA of conductive plug 6P is located at location RB/C3. Each conductive plug involves a thin binding layer of titanium and/or TiW or TiN as well as the bulk plug material, which in this case is tungsten. Overlaying the conductive plugs is a layer of the programmable material 12. The layer of programmable material is intrinsic plasma enhance chemical vapor deposited (PECVD) amorphous silicon and is disposed substantially in a plane 12A. Row conductor 8, like column conductors 7 and 9, includes a bottom barrier layer (for example, TiW or TiN), an intervening aluminum layer, and a top barrier layer (for example, TiW or TiN). The bottom barrier layer of row conductor 8 prevents aluminum from row conductor 8 from migrating into the programmable material 12 and adversely affecting antifuse characteristics. A "programmable material plug overlay design rule" used in generating the layout of the second conventional FPGA ensures that the programmable material covers the top of the conductive plugs and extends in a lateral dimension past the top edges of the conductive plugs by at least a lateral distance 13. Because there is no antifuse disposed at location RB/C2, use of the design rule results in two edges 14 and 15 of the programmable material 12 located at distance 13 from the conductive plugs 5P and 6P, respectively. FIG. 5 (Prior Art) is a top-down diagram of another antifuse structure in the second conventional FPGA where the programmable interconnect is disposed over the logic modules. Here row conductor 8 is made wider to reduce resistance and to decrease the propagation time of signals down the row conductor. Not only are edges 14 and 15 of the programmable material disposed underneath row conductor 8, but corners 16-19 of the programmable material are now also disposed underneath row conductor 8. In addition to the configurations of FIGS. 3 and 5, there are other antifuse structures of the second conventional FPGA that result in programmable material edges and corners being disposed underneath overlaying metal conductors. In this second conventional FPGA: 1) approximately 4% of the antifuses have an associated programmable material corner under a metal conductor within lateral distance DIS of the conductive plug; and 2) approximately 90% of the antifuses have an associated programmable material edge under a metal conductor within lateral distance DIS of the conductive plug. Reducing such edges and corners is desired to increase yield and to improve reliability of an FPGA such as the second conventional FPGA where conductive plug-type antifuses are disposed in a layer (or layers) above logic modules. SUMMARY It is believed that one failure mechanism of antifuses is associated with the existence of programmable material corners and/or edges underneath overlaying conductors. In accordance with the present invention, antifuses of the programmable interconnect structure of an FPGA are disposed in layers over logic modules of the FPGA. These antifuses include a conductive plug and an overlaying region of programmable material (for example, amorphous silicon). To program one of these antifuses, an electrical connection is formed through the programmable material to couple the conductive plug to a metal conductor that overlays the region of programmable material. The metal conductor includes a layer of a barrier metal to separate another metal of the conductor (for example, an aluminum layer) from migrating into the programmable material when the antifuse is unprogrammed. In one embodiment: 1) less than 3% of all the antifuses of the FPGA have a corner (from the top-down perspective) of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse; and 2) less than 75% of all the antifuses of the FPGA have an edge of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse. In a preferred embodiment: 1) the FPGA has no antifuse (0%) that has a corner (from the top-down perspective) of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse; and 2) less than 5% of all the antifuses of the FPGA have an edge of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse. Other embodiments, structures and methods are also disclosed for improving device yield and reliability. This summary does not purport to define the invention. The invention is defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (Prior Art) is a top-down diagram of a conventional FPGA having a programmable interconnect structure employing antifuses. FIG. 2 (Prior Art) is a top-down diagram of a matrix of locations where antifuses may be located in the programmable interconnect structure of a conventional FPGA. FIG. 3 (Prior Art) is a top-down diagram of a conventional FPGA structure. FIG. 4 (Prior Art) is a cross-sectional diagram taken along sectional line SS' of the conventional structure of FIG. 3. FIGS. 5, 6, 8, 10, 12, 14, 16, 18, 20 and 22 (Prior Art) are top-down diagrams of conventional structures that may be found in a conventional field programmable gate array. FIGS. 7, 9, 11, 13, 15, 17, 19, 21 and 23 are top-down diagrams of structures in accordance with embodiments of the present invention. FIG. 7A is a cross-sectional diagram taken along sectional line SS' of the structure of FIG. 7. FIG. 24 is a top-down diagram of a structure in accordance with an embodiment of the present invention. FIG. 25 is a cross-sectional diagram taken along sectional line SS' of the structure of FIG. 24. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS It is believed that antifuse failures are associated with corners of the programmable material of an antifuse being too close to the conductive plug of the antifuse. The conductor in contact with the programmable material of the antifuse has a layer of barrier metal to prevent aluminum from the conductor (or another metal that migrates easily in the programmable material) from penetrating and migrating into the programming material of the antifuse. The corner (a corner when the programmable material is viewed from a top-down perspective) is believed to provide a spot in the barrier metal that is susceptible to failure such that aluminum from the conductor can migrate into the programmable material. This susceptibility may be due to poor step coverage of the barrier metal over the programmable material corner or a weak barrier. In some embodiments, susceptibility to failure may be due to diffusion of the programmable material into overlaying metal as well as or rather than migration of metal from the overlaying metal into the programmable material. In a preferred embodiment of an FPGA having antifuses disposed above logic modules, no antifuse has a corner of its layer of programmable material disposed underneath a row or column conductor (the programmable material separates the conductive plug from the overlaying row or column conductor) within lateral distance DIS of the center axis of the conductive plug of the antifuse. Lateral distance DIS is the lateral distance between the closest two antifuses of the FPGA measured from the antifuse center axis when viewed from a top-down perspective. In some embodiments there are antifuses with such programmable material corners, but efforts are made to reduce their number. In one embodiment, less than 3% of all the antifuses of an FPGA have such corners. It is also believed that antifuse failures are associated with programmable material edges being disposed underneath the row or column conductor within lateral distance DIS of the center axis of the antifuse conductive plug. The edge is believed to provide a spot in the barrier metal that is susceptible to failure such that aluminum from the conductor can migrate into the programmable material. Although it may be impossible to eliminate all such edges from the FPGA, the number of antifuses with such edges is reduced in accordance with the invention. Moreover, the length of many of these edges may also be reduced in accordance with the invention. In a preferred embodiment, less than 5% of all the antifuses of an FPGA have such a programmable material edge. In another embodiment, less than 75% of all the antifuses of an FPGA have such a programmable material edge. FIG. 6 (Prior Art) is a simplified top-down diagram of a conventional structure (the same structure as shown in FIG. 3). There are two vertically extending column conductors 100 and 101 and one horizontally extending row conductor 102. The row conductor extends over the column conductors. There are antifuses disposed at locations RB/C1 and RB/C3, but there is no antifuse at location RB/C2. The edge of the layer programmable material 103 of the antifuse at location RB/C1 is designated with dashed line 104. The edge of the layer programmable material 103 of the antifuse at location RB/C3 is designated with dashed line 105. The edges of the programmable material 103 extend underneath row conductor 102 between locations RB/C1 and RB/C3. One such edge is within lateral distance DIS of the center axis of the antifuse at location RB/C1 and the other such edge is within lateral distance DIS of the center axis of the antifuse at location RB/C3. FIG. 7 is a simplified top-down diagram in accordance with an embodiment of the present invention. There is one common layer of programmable material 103 for both antifuses such that there is no edge or corner of the programmable material 103 under row conductor 102 between locations RB/C1 and RB/C3. FIG. 7A is a simplified cross-sectional diagram of the structure of FIG. 7. Whereas in the structure of FIG. 4 there are edges 14 and 15 of the programmable material 12 underneath the row conductor 8, in the structure of FIG. 7A there are no such edges. (The term "underneath" here does not mean that the edge is directly under the edge of an overlaying and touching metal layer, rather it means the edge is actually underneath the overlaying metal.) The layer of programmable material 103 is made to extend from location RB/C1 to location RB/C3 underneath row conductor 102. The layer of programmable material 103 is disposed substantially in a plane 103A. As in the structure of FIG. 4, layer 10 is an insulator (for example, oxide) and layer 11 is an inter-metal layer of insulation (for example, oxide). Although one particular conductive plug-type antifuse structure is illustrated, it is understood that numerous other antifuse structures may be implemented. An inverted conductive plug-type antifuse can be employed where the programmable material is disposed in a plane underneath the conductive plug. A via-type antifuse can also be implemented where the programmable material extends into the opening in the inter-metal layer insulation. The programmable material may involve other materials and/or layers of materials, for example, a layer or layers of polysilicon, silicon nitride and/or silicon oxide. A double barrier layer can be formed by forming a layer of a barrier metal such as TiN over an amorphous silicon layer, etching the amorphous silicon layer and the barrier metal layer at the same time to form the region of the programmable material (with a protective piece of TiN on top of the programmable material), then oxidizing the top surface of the protective TiN to stuff grain boundaries in the TiN, then over the top of this structure forming the top conductor including a bottom barrier layer of TiN followed by an intervening layer of aluminum followed by a top barrier layer of TiN. FIG. 8 (Prior Art) is a simplified top-down diagram of another conventional structure. There are two vertically extending column conductors 106 and 107 and one horizontally extending row conductor 108. There are antifuses at locations RB/C1 and RB/C4 but there are no antifuses at locations RB/C2 and RB/C3. As in the structure of FIG. 6, there are undesirable edges of the programmable material 109 underneath row conductor 108 between locations RB/C1 and RB/C4. FIG. 9 is a simplified top-down diagram in accordance with an embodiment of the present invention. There is one common layer of programmable material 109 for both of the antifuses such that there is no edge or corner of the programmable material 109 under row conductor 108 between locations RB/C1 and RB/C4. FIG. 10 (Prior Art) is a simplified top-down diagram of another conventional structure. There are two vertically extending column conductors 110 and 111 and two horizontally extending row conductors 112 and 113. There are antifuses at locations RA/C1, RA/C3, RB/C1 and RB/C3. There are no antifuses at locations RA/C2 and RB/C2. Again, there are undesirable edges of the programmable material 114 underneath row conductors 112 and 113. FIG. 11 is a simplified top-down diagram in accordance with an embodiment of the present invention. There is one common layer of programmable material 114 for all of the four antifuses such that there is no edge or corner of the programmable material 114 under either of row conductors 112 or 113. FIG. 12 (Prior Art) is a simplified top-down diagram of another conventional structure. There are three vertically extending column conductors 115, 116 and 117, two horizontally extending row conductors 118 and 119, and five antifuses at locations RA/C1, RA/C2, RA/C3, RB/C1 and RB/C3. There is no antifuses at location RB/C2. There are undesirable edges of the programmable material 120 underneath row conductor 119 where there is a cutout of the programmable material 120 in the vicinity of location RB/C2. FIG. 13 is a simplified top-down diagram in accordance with an embodiment of the present invention. There is no edge or corner of programmable material 120 under row conductor 119 because the layer of programmable material is made to extend from location RB/C1 to location RB/C3 across location RB/C2. FIG. 14 (Prior Art) is a simplified top-down diagram of another conventional structure. There are three vertically extending column conductors 121, 122 and 123, three horizontally extending row conductors 124, 125 and 126, and seven antifuses at locations RA/C1, RA/C2, RA/C3, RB/C1, RB/C3, RC/C1 and RC/C3. There are no antifuses at locations RB/C2 or RC/C2. In this structure, there is a conductive via 127 at location RC/C2. Via 127 is a permanent connection from column conductor C2 to row conductor RC. It has the same basic structure as an antifuse except it has no programmable material, rather the top of its conductive plug is in permanent contact with overlaying row conductor 126. Such a via breaks the plane of the programmable material 128. In this illustration, the edge of the programmable material 128 is designated with a dashed line, the programmable material being disposed on the side of the dashed line opposite the via symbol. Note that there are undesirable edges of the programmable material 128 underneath row conductors 125 and 126. FIG. 15 is a simplified top-down diagram in accordance with an embodiment of the present invention. The undesirable edges of programmable material 128 under row conductor 125 are eliminated by extending the layer of programmable material from location RB/C1 to location RB/C3 across location RB/C2. The undesirable edges underneath row conductor 126, however, are not removed due to the requirement that via 127 break the plane of the programmable material. FIG. 16 (Prior Art) is a simplified top-down diagram of another conventional structure. The same symbols are used as are used in FIGS. 6-15. Note that the layer of programmable material 129 is in two parts and has edges underneath each of the horizontally extending row conductors. FIG. 17 is a simplified top-down diagram in accordance with an embodiment of the present invention. The undesirable edges of programmable material 129 under row conductors 130, 131, 132 and 133 are eliminated. An edge of the programmable material 129 forms a square such that there appears to be a square cutout in the programmable material layer around via 134. FIG. 18 (Prior Art) is a simplified top-down diagram of another conventional structure. The same symbols are used as are used in FIGS. 6-17. The layer of programmable material 135 again is in two parts and has edges underneath each of the horizontally extending row conductors. FIG. 19 is a simplified top-down diagram in accordance with an embodiment of the present invention. The undesirable edges of programmable material 135 under row conductor 136 is eliminated. FIG. 20 (Prior Art) is a simplified top-down diagram of another conventional structure. The same symbols are used as are used in FIGS. 6-19. There is a ring of antifuses surrounding via 138. The layer of programmable material 137 for the antifuses therefore also surrounds via 138. FIG. 21 is a simplified top-down diagram in accordance with an embodiment of the present invention. The undesirable edges of programmable material 137 under row conductors 139 and 140 are eliminated. Although extending the edge of the programmable material to the right to extend over location RC/C2 and extending the edge of the programmable material to the left to extend over location RC/C4 does not eliminate an edge under row conductor 141, it does move the two programmable material edges farther from the antifuses at locations RC/C1 and RC/C5. Due to the greater distance from the undesirable edge to the location of the antifuse conductive plug, the consequence of aluminum intrusion into the programmable material is minimized. Accordingly, the programmable material layer of an FPGA employing antifuses is made to cover as much integrated circuit area in the vicinity of antifuses as possible (preferably substantially all of the integrated circuit area is covered, the only exception being due to conductors having to pass through the plane of the programmable material, such as vias that form permanent connections through the plane of the programmable material). The cutouts in the programmable material layer for vias in this embodiment may appear as squares when viewed from a top-down perspective. Alternatively, the programmable material does not cover the entire integrated circuit area but rather is made to extend everywhere the overlaying metal layer goes, the main exceptions being due to the necessity of vias making connections from the metal layer to underlying layers through the plane of the programmable material. FIG. 22 (Prior Art) is a simplified top-down diagram of another conventional structure. An antifuse 142 can be programmable to couple conductor 143 to overlaying metal conductor 144. The edge of the programmable material of the antifuse appears as a square 145 when viewed from a top-down perspective. Distance 146 is the programmable material plug overlay design rule distance. Conductor 144 is a relatively wide low resistance conductor such as a "quad wire" conductor. FIG. 23 is a simplified top-down diagram in accordance with an embodiment of the present invention. Conductor 144 is narrowed in the vicinity of antifuse 142 but is wider elsewhere to make the conductor a low resistance conductor. Not only are programmable material corners 146-149 not disposed underneath conductor 144, but also the length of the edge of programmable material 145 that is underneath conductor 144 is reduced. FIG. 24 is a simplified top-down diagram in accordance with an embodiment of the present invention. FIG. 25 is a cross-sectional diagram taken along sectional line SS' of FIG. 24. In this example, there is one antifuse 150 for programmably coupling lower level metal conductor 151 to upper level metal conductor 152. Ordinary use of the programmable material plug overlay design rule in this example would generally result in a square, one of the sides of the square being designated with dashed line 153. This would, however, result in a programmable material edge 153 underneath conductor 152 within distance DIS of antifuse 150. In accordance with one embodiment of the present invention, the programmable material is made to extend to the right under conductor 152 in the direction of conductor 152 a lateral distance greater than lateral distance DIS. In the illustrated example, the programmable material 154 does not go everywhere metal conductor 152 goes, but in other examples it could go everywhere except for where a conductive via couples conductor 152 to a lower level through the plane of the programmable material. It is to be understood that the antifuse structures of conventional FPGAs set forth in the figures and described in the associated text are illustrative of conventional antifuse structures, and are to be considered to be prior art structures, but that a particular conventional FPGA does not necessarily exist that contains the conventional structures exactly as illustrated. The figures of conventional FPGA antifuse structures are provided to facilitate understanding, consideration and examination of the prior art. Although the invention is described in connection with certain specific embodiments for instructional purposes, the invention is not limited to the specific embodiments. Teachings of this disclosure relate to preventing failures in antifuses other than conductive plug-type antifuses due to edges and/or corners of the antifuse programmable material making a barrier metal layer susceptible to failure. Other types of antifuses, other conductor geometries and structures, and programmable materials other than amorphous silicon can be employed in accordance with the invention. Antifuses can be disposed between first layer metal and second layer metal, between second layer metal and third layer metal, between third layer metal and fourth layer metal, and/or between other layers of metal. In the process of laying out an FPGA, a design rule can be used that forbids a corner of the programmable material region of an antifuse from being disposed underneath a metal conductor in contact with the programmable material region. Accordingly, modifications, adaptations and combinations of various aspects of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.
A field programmable gate array has antifuses disposed over logic modules. Each of these antifuses includes a conductive plug and an overlaying region of programmable material (for example, amorphous silicon). To program one of these antifuses, an electric connection is formed through the programmable material to couple the conductive plug to a metal conductor that overlays the region of programmable material. The metal conductor includes a layer of a barrier metal to separate another metal of the conductor (for example, aluminum from an aluminum layer) from migrating into the programmable material when the antifuse is unprogrammed. In some embodiments, less than three percent of all antifuses of the field programmable gate array has a corner (from the top-down perspective) of the region of programmable material that is disposed (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse. In some embodiments, less than seventy-five percent of all antifuses of the field programmable gate array have an edge of the region of programmable material disposed (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse. Other antifuse structures and methods are also disclosed for preventing programmable material corners and/or edges from compromising yield and/or reliability of programmable devices.
Summarize the document in concise, focusing on the main idea's functionality and advantages.
[ "This application is a division of application Ser.", "No. 09/133,999 filed Aug. 13, 1998 now U.S. Pat. No. 5,955,751.", "FIELD OF THE INVENTION This invention relates to programmable integrated circuits (for example, field programmable gate arrays or "FPGAs") employing antifuses.", "BACKGROUND AND RELATED PRIOR ART A field programmable gate array is a versatile integrated circuit chip, the internal circuitry of which may be configured by an individual user to realize a user-specific circuit.", "To configure a field programmable gate array, the user configures an on-chip interconnect structure of the field programmable gate array so that selected inputs and selected outputs of selected on-chip logic components are connected together in such a way that the resulting circuit is the user-specific circuit desired by the user.", "For additional background on antifuse-based field programmable gate array structures, the reader is referred to: U.S. Pat. Nos. 5,495,181, 5,424,655, 5,122,685, 5,055,718, 4,873,459, 5,502,315, 5,362,676, 5,557,136, 5,308,795 and 5,233,217;", "U.S. patent application Ser.", "No. 08/667,702 now U.S. Pat. No. 5,825,201 issued on Oct. 10, 1998 entitled "ramming Architecture For A Programmable Integrated Circuit Employing Antifuses"", "by Paige A. Kolze, filed Jun. 21, 1996;", "the 1996/97 QuickLogic Data Book;", "the 1996 Actel FPGA Data Book and Design Guide;", "and the book entitled "Field-Programmable Gate Arrays"", "by Stephen Brown et al.", ", Kluwer Academic Publishers (1992) (the subject matter of these documents is incorporated herein by reference).", "FIG. 1 (Prior Art) is a top-down diagram of a first conventional field programmable gate array 1 (for example, the QL 16X24 QuickLogic field programmable gate array in the pASIC1 family).", "Field programmable gate array (FPGA) 1 includes a plurality of interface cells 2, a plurality of logic modules 3 arranged in rows and columns, and a programmable interconnect structure 4 employing antifuses.", "The programmable interconnect is disposed in spaces between the rows and columns of logic modules.", "FIG. 2 (Prior Art) is a top-down diagram of a matrix of locations.", "Many of the antifuses of the programmable interconnect structure of FPGA 1 are disposed in such a matrix.", "The rows of locations are labeled with row designators RA, RB, RC and so forth.", "The columns of locations are labeled with column designators C1, C2, C3 and so forth.", "For each column, there is a vertically extending column conductor (not shown) that extends underneath the locations of its column.", "For each row, there is a horizontally extending row conductor (not shown) that extends underneath the locations of its row.", "The row conductors extend in a plane over the plane of the column conductors.", "Antifuses are disposed at the locations illustrated in FIG. 2 where the row conductors cross the column conductors.", "For example, to couple vertically extending column conductor C3 to horizontally extending row conductor R4, an antifuse disposed at location C3/R4 would be programmed.", "The lateral distance DIS between respective antifuses in a row and between respective antifuses in a column is the minimum lateral spacing between antifuses on the FPGA.", "No two antifuses of the FPGA are separated by a lateral distance smaller than lateral distance DIS.", "In FPGA 1, some of the matrix locations are not populated with antifuses.", "Some of the conductors are made wider to reduce conductor resistance to speed the propagation of signals through the conductor.", "Distances greater than distance DIS separate some of the rows and/or columns to accommodate wider conductors.", "In this first conventional FPGA: 1) the antifuses are conductive plug-type antifuses (for more details on conductive plug-type antifuses, see the description below);", "2) none of the antifuses has an associated programmable material corner under a metal conductor within lateral distance DIS of the conductive plug of the antifuse (for more details on what such a programmable material corner is, see the description below);", "and 3) approximately 20 percent of the antifuses have programmable material edges under a metal conductor within lateral distance DIS of the conductive plug of the antifuse (for more details on what such a programmable material edge is, see the description below).", "FIG. 3 (Prior Art) is a top-down diagram of two antifuses 5 and 6 of a second conventional FPGA (for example, the QL2007 QuickLogic FPGA in the pASIC2 family).", "To increase packing density in this second conventional FPGA, the spaces between logic modules of the first conventional FPGA are substantially eliminated in the center portion of the integrated circuit and the programmable interconnect structure is disposed in layers above the logic modules.", "A matrix of antifuses is disposed over each respective logic module.", "For example, an antifuse 5 is disposed at location RB/C1 and an antifuse 6 is disposed at location RB/C3.", "There is no antifuse at location RB/C2.", "An inter-metal layer insulator covers the underlying column conductors and separates the column conductors from the overlaying row conductor.", "If programmed, antifuse 5 would couple vertically extending column conductor 7 to overlaying horizontally extending row conductor 8.", "If programmed, antifuse 6 would couple vertically extending column conductor 9 to horizontally extending row conductor 8.", "In the second conventional FPGA, the antifuses are also conductive plug-type antifuses.", "Each conductive plug-type antifuse includes a conductive plug and a layer of a programmable material disposed over the conductive plug between the top of the plug and the bottom of the overlaying row conductor.", "The conductive plug is disposed in an opening in the inter-metal layer insulator.", "When programmed, a conductive filament forms through the layer of programmable material to couple the conductive plug to the overlaying row conductor.", "For additional background information on conductive plug-type antifuse structures and how to make them, see U.S. Pat. Nos. 5,557,136, 5,308,795 and 5,233,217, and the U.S. patent application No. 09/133,998, now allowed entitled "Metal-to-Metal Antifuse Having Improved Barrier Layer", by Rajiv Jain et al.", ", filed Aug. 13, 1998 (the subject matter of these patents and this patent application is incorporated herein by reference).", "FIG. 4 (Prior Art) is a cross-sectional diagram taken along sectional line SS'", "of FIG. 3. Layer 10 is a layer of insulation (for example, silicon dioxide).", "The antifuses are disposed in layers above the substrate such that layer 10 insulates the antifuse and programmable interconnect layers from underlying logic module transistors in the substrate.", "Column conductor 7 and column conductor 9 each includes a bottom barrier layer (for example, TiW or TiN), a relatively thick layer involving aluminum, and a top barrier layer (for example, TiW or TiN).", "Conductive plugs 5P and 6P of antifuses 5 and 6 are disposed in openings in inter-metal layer insulation 11.", "The center axis 5PA of conductive plug 5P is located at location RB/C I and the center axis 6PA of conductive plug 6P is located at location RB/C3.", "Each conductive plug involves a thin binding layer of titanium and/or TiW or TiN as well as the bulk plug material, which in this case is tungsten.", "Overlaying the conductive plugs is a layer of the programmable material 12.", "The layer of programmable material is intrinsic plasma enhance chemical vapor deposited (PECVD) amorphous silicon and is disposed substantially in a plane 12A.", "Row conductor 8, like column conductors 7 and 9, includes a bottom barrier layer (for example, TiW or TiN), an intervening aluminum layer, and a top barrier layer (for example, TiW or TiN).", "The bottom barrier layer of row conductor 8 prevents aluminum from row conductor 8 from migrating into the programmable material 12 and adversely affecting antifuse characteristics.", "A "programmable material plug overlay design rule"", "used in generating the layout of the second conventional FPGA ensures that the programmable material covers the top of the conductive plugs and extends in a lateral dimension past the top edges of the conductive plugs by at least a lateral distance 13.", "Because there is no antifuse disposed at location RB/C2, use of the design rule results in two edges 14 and 15 of the programmable material 12 located at distance 13 from the conductive plugs 5P and 6P, respectively.", "FIG. 5 (Prior Art) is a top-down diagram of another antifuse structure in the second conventional FPGA where the programmable interconnect is disposed over the logic modules.", "Here row conductor 8 is made wider to reduce resistance and to decrease the propagation time of signals down the row conductor.", "Not only are edges 14 and 15 of the programmable material disposed underneath row conductor 8, but corners 16-19 of the programmable material are now also disposed underneath row conductor 8.", "In addition to the configurations of FIGS. 3 and 5, there are other antifuse structures of the second conventional FPGA that result in programmable material edges and corners being disposed underneath overlaying metal conductors.", "In this second conventional FPGA: 1) approximately 4% of the antifuses have an associated programmable material corner under a metal conductor within lateral distance DIS of the conductive plug;", "and 2) approximately 90% of the antifuses have an associated programmable material edge under a metal conductor within lateral distance DIS of the conductive plug.", "Reducing such edges and corners is desired to increase yield and to improve reliability of an FPGA such as the second conventional FPGA where conductive plug-type antifuses are disposed in a layer (or layers) above logic modules.", "SUMMARY It is believed that one failure mechanism of antifuses is associated with the existence of programmable material corners and/or edges underneath overlaying conductors.", "In accordance with the present invention, antifuses of the programmable interconnect structure of an FPGA are disposed in layers over logic modules of the FPGA.", "These antifuses include a conductive plug and an overlaying region of programmable material (for example, amorphous silicon).", "To program one of these antifuses, an electrical connection is formed through the programmable material to couple the conductive plug to a metal conductor that overlays the region of programmable material.", "The metal conductor includes a layer of a barrier metal to separate another metal of the conductor (for example, an aluminum layer) from migrating into the programmable material when the antifuse is unprogrammed.", "In one embodiment: 1) less than 3% of all the antifuses of the FPGA have a corner (from the top-down perspective) of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse;", "and 2) less than 75% of all the antifuses of the FPGA have an edge of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse.", "In a preferred embodiment: 1) the FPGA has no antifuse (0%) that has a corner (from the top-down perspective) of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse;", "and 2) less than 5% of all the antifuses of the FPGA have an edge of the region of programmable material (within lateral distance DIS of the conductive plug) underneath the metal conductor of that antifuse.", "Other embodiments, structures and methods are also disclosed for improving device yield and reliability.", "This summary does not purport to define the invention.", "The invention is defined by the claims.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (Prior Art) is a top-down diagram of a conventional FPGA having a programmable interconnect structure employing antifuses.", "FIG. 2 (Prior Art) is a top-down diagram of a matrix of locations where antifuses may be located in the programmable interconnect structure of a conventional FPGA.", "FIG. 3 (Prior Art) is a top-down diagram of a conventional FPGA structure.", "FIG. 4 (Prior Art) is a cross-sectional diagram taken along sectional line SS'", "of the conventional structure of FIG. 3. FIGS. 5, 6, 8, 10, 12, 14, 16, 18, 20 and 22 (Prior Art) are top-down diagrams of conventional structures that may be found in a conventional field programmable gate array.", "FIGS. 7, 9, 11, 13, 15, 17, 19, 21 and 23 are top-down diagrams of structures in accordance with embodiments of the present invention.", "FIG. 7A is a cross-sectional diagram taken along sectional line SS'", "of the structure of FIG. 7. FIG. 24 is a top-down diagram of a structure in accordance with an embodiment of the present invention.", "FIG. 25 is a cross-sectional diagram taken along sectional line SS'", "of the structure of FIG. 24.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS It is believed that antifuse failures are associated with corners of the programmable material of an antifuse being too close to the conductive plug of the antifuse.", "The conductor in contact with the programmable material of the antifuse has a layer of barrier metal to prevent aluminum from the conductor (or another metal that migrates easily in the programmable material) from penetrating and migrating into the programming material of the antifuse.", "The corner (a corner when the programmable material is viewed from a top-down perspective) is believed to provide a spot in the barrier metal that is susceptible to failure such that aluminum from the conductor can migrate into the programmable material.", "This susceptibility may be due to poor step coverage of the barrier metal over the programmable material corner or a weak barrier.", "In some embodiments, susceptibility to failure may be due to diffusion of the programmable material into overlaying metal as well as or rather than migration of metal from the overlaying metal into the programmable material.", "In a preferred embodiment of an FPGA having antifuses disposed above logic modules, no antifuse has a corner of its layer of programmable material disposed underneath a row or column conductor (the programmable material separates the conductive plug from the overlaying row or column conductor) within lateral distance DIS of the center axis of the conductive plug of the antifuse.", "Lateral distance DIS is the lateral distance between the closest two antifuses of the FPGA measured from the antifuse center axis when viewed from a top-down perspective.", "In some embodiments there are antifuses with such programmable material corners, but efforts are made to reduce their number.", "In one embodiment, less than 3% of all the antifuses of an FPGA have such corners.", "It is also believed that antifuse failures are associated with programmable material edges being disposed underneath the row or column conductor within lateral distance DIS of the center axis of the antifuse conductive plug.", "The edge is believed to provide a spot in the barrier metal that is susceptible to failure such that aluminum from the conductor can migrate into the programmable material.", "Although it may be impossible to eliminate all such edges from the FPGA, the number of antifuses with such edges is reduced in accordance with the invention.", "Moreover, the length of many of these edges may also be reduced in accordance with the invention.", "In a preferred embodiment, less than 5% of all the antifuses of an FPGA have such a programmable material edge.", "In another embodiment, less than 75% of all the antifuses of an FPGA have such a programmable material edge.", "FIG. 6 (Prior Art) is a simplified top-down diagram of a conventional structure (the same structure as shown in FIG. 3).", "There are two vertically extending column conductors 100 and 101 and one horizontally extending row conductor 102.", "The row conductor extends over the column conductors.", "There are antifuses disposed at locations RB/C1 and RB/C3, but there is no antifuse at location RB/C2.", "The edge of the layer programmable material 103 of the antifuse at location RB/C1 is designated with dashed line 104.", "The edge of the layer programmable material 103 of the antifuse at location RB/C3 is designated with dashed line 105.", "The edges of the programmable material 103 extend underneath row conductor 102 between locations RB/C1 and RB/C3.", "One such edge is within lateral distance DIS of the center axis of the antifuse at location RB/C1 and the other such edge is within lateral distance DIS of the center axis of the antifuse at location RB/C3.", "FIG. 7 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "There is one common layer of programmable material 103 for both antifuses such that there is no edge or corner of the programmable material 103 under row conductor 102 between locations RB/C1 and RB/C3.", "FIG. 7A is a simplified cross-sectional diagram of the structure of FIG. 7. Whereas in the structure of FIG. 4 there are edges 14 and 15 of the programmable material 12 underneath the row conductor 8, in the structure of FIG. 7A there are no such edges.", "(The term "underneath"", "here does not mean that the edge is directly under the edge of an overlaying and touching metal layer, rather it means the edge is actually underneath the overlaying metal.) The layer of programmable material 103 is made to extend from location RB/C1 to location RB/C3 underneath row conductor 102.", "The layer of programmable material 103 is disposed substantially in a plane 103A.", "As in the structure of FIG. 4, layer 10 is an insulator (for example, oxide) and layer 11 is an inter-metal layer of insulation (for example, oxide).", "Although one particular conductive plug-type antifuse structure is illustrated, it is understood that numerous other antifuse structures may be implemented.", "An inverted conductive plug-type antifuse can be employed where the programmable material is disposed in a plane underneath the conductive plug.", "A via-type antifuse can also be implemented where the programmable material extends into the opening in the inter-metal layer insulation.", "The programmable material may involve other materials and/or layers of materials, for example, a layer or layers of polysilicon, silicon nitride and/or silicon oxide.", "A double barrier layer can be formed by forming a layer of a barrier metal such as TiN over an amorphous silicon layer, etching the amorphous silicon layer and the barrier metal layer at the same time to form the region of the programmable material (with a protective piece of TiN on top of the programmable material), then oxidizing the top surface of the protective TiN to stuff grain boundaries in the TiN, then over the top of this structure forming the top conductor including a bottom barrier layer of TiN followed by an intervening layer of aluminum followed by a top barrier layer of TiN.", "FIG. 8 (Prior Art) is a simplified top-down diagram of another conventional structure.", "There are two vertically extending column conductors 106 and 107 and one horizontally extending row conductor 108.", "There are antifuses at locations RB/C1 and RB/C4 but there are no antifuses at locations RB/C2 and RB/C3.", "As in the structure of FIG. 6, there are undesirable edges of the programmable material 109 underneath row conductor 108 between locations RB/C1 and RB/C4.", "FIG. 9 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "There is one common layer of programmable material 109 for both of the antifuses such that there is no edge or corner of the programmable material 109 under row conductor 108 between locations RB/C1 and RB/C4.", "FIG. 10 (Prior Art) is a simplified top-down diagram of another conventional structure.", "There are two vertically extending column conductors 110 and 111 and two horizontally extending row conductors 112 and 113.", "There are antifuses at locations RA/C1, RA/C3, RB/C1 and RB/C3.", "There are no antifuses at locations RA/C2 and RB/C2.", "Again, there are undesirable edges of the programmable material 114 underneath row conductors 112 and 113.", "FIG. 11 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "There is one common layer of programmable material 114 for all of the four antifuses such that there is no edge or corner of the programmable material 114 under either of row conductors 112 or 113.", "FIG. 12 (Prior Art) is a simplified top-down diagram of another conventional structure.", "There are three vertically extending column conductors 115, 116 and 117, two horizontally extending row conductors 118 and 119, and five antifuses at locations RA/C1, RA/C2, RA/C3, RB/C1 and RB/C3.", "There is no antifuses at location RB/C2.", "There are undesirable edges of the programmable material 120 underneath row conductor 119 where there is a cutout of the programmable material 120 in the vicinity of location RB/C2.", "FIG. 13 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "There is no edge or corner of programmable material 120 under row conductor 119 because the layer of programmable material is made to extend from location RB/C1 to location RB/C3 across location RB/C2.", "FIG. 14 (Prior Art) is a simplified top-down diagram of another conventional structure.", "There are three vertically extending column conductors 121, 122 and 123, three horizontally extending row conductors 124, 125 and 126, and seven antifuses at locations RA/C1, RA/C2, RA/C3, RB/C1, RB/C3, RC/C1 and RC/C3.", "There are no antifuses at locations RB/C2 or RC/C2.", "In this structure, there is a conductive via 127 at location RC/C2.", "Via 127 is a permanent connection from column conductor C2 to row conductor RC.", "It has the same basic structure as an antifuse except it has no programmable material, rather the top of its conductive plug is in permanent contact with overlaying row conductor 126.", "Such a via breaks the plane of the programmable material 128.", "In this illustration, the edge of the programmable material 128 is designated with a dashed line, the programmable material being disposed on the side of the dashed line opposite the via symbol.", "Note that there are undesirable edges of the programmable material 128 underneath row conductors 125 and 126.", "FIG. 15 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "The undesirable edges of programmable material 128 under row conductor 125 are eliminated by extending the layer of programmable material from location RB/C1 to location RB/C3 across location RB/C2.", "The undesirable edges underneath row conductor 126, however, are not removed due to the requirement that via 127 break the plane of the programmable material.", "FIG. 16 (Prior Art) is a simplified top-down diagram of another conventional structure.", "The same symbols are used as are used in FIGS. 6-15.", "Note that the layer of programmable material 129 is in two parts and has edges underneath each of the horizontally extending row conductors.", "FIG. 17 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "The undesirable edges of programmable material 129 under row conductors 130, 131, 132 and 133 are eliminated.", "An edge of the programmable material 129 forms a square such that there appears to be a square cutout in the programmable material layer around via 134.", "FIG. 18 (Prior Art) is a simplified top-down diagram of another conventional structure.", "The same symbols are used as are used in FIGS. 6-17.", "The layer of programmable material 135 again is in two parts and has edges underneath each of the horizontally extending row conductors.", "FIG. 19 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "The undesirable edges of programmable material 135 under row conductor 136 is eliminated.", "FIG. 20 (Prior Art) is a simplified top-down diagram of another conventional structure.", "The same symbols are used as are used in FIGS. 6-19.", "There is a ring of antifuses surrounding via 138.", "The layer of programmable material 137 for the antifuses therefore also surrounds via 138.", "FIG. 21 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "The undesirable edges of programmable material 137 under row conductors 139 and 140 are eliminated.", "Although extending the edge of the programmable material to the right to extend over location RC/C2 and extending the edge of the programmable material to the left to extend over location RC/C4 does not eliminate an edge under row conductor 141, it does move the two programmable material edges farther from the antifuses at locations RC/C1 and RC/C5.", "Due to the greater distance from the undesirable edge to the location of the antifuse conductive plug, the consequence of aluminum intrusion into the programmable material is minimized.", "Accordingly, the programmable material layer of an FPGA employing antifuses is made to cover as much integrated circuit area in the vicinity of antifuses as possible (preferably substantially all of the integrated circuit area is covered, the only exception being due to conductors having to pass through the plane of the programmable material, such as vias that form permanent connections through the plane of the programmable material).", "The cutouts in the programmable material layer for vias in this embodiment may appear as squares when viewed from a top-down perspective.", "Alternatively, the programmable material does not cover the entire integrated circuit area but rather is made to extend everywhere the overlaying metal layer goes, the main exceptions being due to the necessity of vias making connections from the metal layer to underlying layers through the plane of the programmable material.", "FIG. 22 (Prior Art) is a simplified top-down diagram of another conventional structure.", "An antifuse 142 can be programmable to couple conductor 143 to overlaying metal conductor 144.", "The edge of the programmable material of the antifuse appears as a square 145 when viewed from a top-down perspective.", "Distance 146 is the programmable material plug overlay design rule distance.", "Conductor 144 is a relatively wide low resistance conductor such as a "quad wire"", "conductor.", "FIG. 23 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "Conductor 144 is narrowed in the vicinity of antifuse 142 but is wider elsewhere to make the conductor a low resistance conductor.", "Not only are programmable material corners 146-149 not disposed underneath conductor 144, but also the length of the edge of programmable material 145 that is underneath conductor 144 is reduced.", "FIG. 24 is a simplified top-down diagram in accordance with an embodiment of the present invention.", "FIG. 25 is a cross-sectional diagram taken along sectional line SS'", "of FIG. 24.", "In this example, there is one antifuse 150 for programmably coupling lower level metal conductor 151 to upper level metal conductor 152.", "Ordinary use of the programmable material plug overlay design rule in this example would generally result in a square, one of the sides of the square being designated with dashed line 153.", "This would, however, result in a programmable material edge 153 underneath conductor 152 within distance DIS of antifuse 150.", "In accordance with one embodiment of the present invention, the programmable material is made to extend to the right under conductor 152 in the direction of conductor 152 a lateral distance greater than lateral distance DIS.", "In the illustrated example, the programmable material 154 does not go everywhere metal conductor 152 goes, but in other examples it could go everywhere except for where a conductive via couples conductor 152 to a lower level through the plane of the programmable material.", "It is to be understood that the antifuse structures of conventional FPGAs set forth in the figures and described in the associated text are illustrative of conventional antifuse structures, and are to be considered to be prior art structures, but that a particular conventional FPGA does not necessarily exist that contains the conventional structures exactly as illustrated.", "The figures of conventional FPGA antifuse structures are provided to facilitate understanding, consideration and examination of the prior art.", "Although the invention is described in connection with certain specific embodiments for instructional purposes, the invention is not limited to the specific embodiments.", "Teachings of this disclosure relate to preventing failures in antifuses other than conductive plug-type antifuses due to edges and/or corners of the antifuse programmable material making a barrier metal layer susceptible to failure.", "Other types of antifuses, other conductor geometries and structures, and programmable materials other than amorphous silicon can be employed in accordance with the invention.", "Antifuses can be disposed between first layer metal and second layer metal, between second layer metal and third layer metal, between third layer metal and fourth layer metal, and/or between other layers of metal.", "In the process of laying out an FPGA, a design rule can be used that forbids a corner of the programmable material region of an antifuse from being disposed underneath a metal conductor in contact with the programmable material region.", "Accordingly, modifications, adaptations and combinations of various aspects of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims." ]
BACKGROUND OF THE INVENTION The present invention relates to ensuring bandwidth availability in a communications system, and more particularly to ensuring such bandwidth availability in a communications system. Even more particularly, the present invention relates to ensuring bandwidth availability in a point-to-point messaging portion of a digital control channel in a communications system. Interim Standard (IS) 136 (promulgated by the Telecommunications Industry Association) adds a Digital Control Channel (DCCH) to IS-54B, an 800 MHZ TDMA Cellular Standard. The fundamental unit of measure in the digital control channel is a slot. Slots are logically combined (in groups of 16 for a half-rate digital control channel and 32 for a full-rate digital control channel) to form "Superframes". Of the slots in a Superframe available for signaling, some are designated by the base station (BMI) for broadcast (point-to-multipoint) messaging and the rest for point-to-point messaging. In order for the base station to be able to notify (or "page") a mobile station (MS) of an incoming call (or other impending transaction), the mobile station is assigned to one and only one of the slots in a Superframe available for point-to-point messaging on the forward digital control channel (i.e., that portion of the digital control channel used to transmit messages from the base station to the mobile station). Note that the term mobile station is used herein to refer to a radio unit in a communications system, and is not limited to being "mobile." The term "mobile" unit is used herein merely because of its wide (and perhaps unfortunate) acceptance and clear meaning in the communications arts, which includes radio units that are "stationary" or "fixed". When the base station needs to "page" the mobile station, i.e., notify the mobile station that it has an incoming call (or other impending transaction), the base station transmits a "page message" or a "hard page" in the assigned slot. (An advantageous approach to utilizing "hard pages" is described in U.S. patent pending application Ser. No. 08/394,091, entitled OPTIMAL PAGING OF ONE OR TWO MOBILE STATIONS USING A HARD PAGE SLOT, commonly invented and assigned with the present patent document, incorporated herein by reference.) Under quiescent conditions, the mobile station need only monitor this assigned slot in the Superframe. Thus, the mobile station is able to "sleep" while the other 31 slots of the Superframe are being transmitted. In addition, because every other Superframe transmitted (i.e., every primary Superframe) by the base station is followed by a Superframe (secondary Superframe) having identical point-to-point paging slots, the mobile unit can sleep during every other entire Superframe. For other types of point-to-point traffic, however, the mobile station is not assigned to a specific slot in a Superframe; rather, when it is expecting a "non-page message," i.e., not a message intended to notify the mobile station of an incoming call (or other impending transaction), from the base station, the mobile station is required to search for non-page messages addressed to itself in each slot available for point-to-point messaging within the Superframe. Currently, mobile stations are hashed to a slot in the Superframe (called a PCH Subchannel) where the mobile station it expects to receive page traffic. Nominally, the mobile station is required to read this same slot in every other Superframe. For illustration purposes, assume a minimal full-rate digital control channel containing four broadcast control channel (BCCH) slots and no Reserved slots. Hence, there are 28 point-to-point message slots, i.e., point-to-point messaging channel slots available for paging (i.e., available for use as PCH Subchannels.) If only 10% of the UPR maximum paging capacity (i.e., User Performance Requirements maximum paging capacity, which is defined as 373,000 pages/hour, or 14 pages/hyperframe by C.T.I.A.) is assumed, then up to one-half of the available point-to-point messaging channel bandwidth could be dedicated to paging. As either the paging traffic increases or the number of point-to-point messaging slots decrease (due to, e.g., additional BCCH messaging), the ratio of pages to PCH Subchannels can approach or exceed 1:1. The consequence of an increase in paging traffic or corresponding decrease in point-to-point messaging channel bandwidth is that the number of slots available for other messages (e.g., non-page messages) is reduced, and consecutive slots for multi-slot messages become scarce. (The term multi-slot message, as used herein, refers to a page message or a non-page message that spans more than one point-to-point messaging channel slot.) Thus throughput of multi-slot messages and non-page messages may be decreased as paging traffic increases, causing delay in the transmission of such messages. As used herein, the terms "page message" and "hard page" refers to one or more slots of data transmitted from a base station over the point-to-point messaging channel that contains information intended to signal one (or possibly more) of a plurality of transceiver units that such transceiver unit(s) have an incoming call. (An incoming call can be, e.g., a voice call or any other type of incoming call capable of being serviced by the base station and transceiver units.) The term "non-page message" refers to any slots of data transmitted over the point-to-point messaging channel that are not "page messages" or "hard pages." Since IS-136 provides for multi-page PCH frames (meaning that more than one mobile station may be paged in a single PCH Subchannel), the volume of available PCH Subchannels, i.e., point-to-point messaging slots assignable as PCH Subchannels, is not a primary issue. However, to compensate for the decrease in bandwidth available for single and multi-slot non-page point-to-point message traffic, the base station must increasingly rely on a technique known as "PCH Continuation" to open up gaps into which this non-page point-to-point message traffic can be accommodated. In a worst case scenario, pages must be delayed, i.e., displaced into later slots, in order to allow some minimal bandwidth for non-page point-to-point message traffic. Such delay, when it affects pages destined for PCH Subchannels late in the primary Superframe, may result in such pages being delayed into a subsequent primary Superframe. PCH Continuation (PCON) is the process by which the base station directs a mobile station to continue reading a number of point-to-point messaging slots after it first reads its assigned PCH Subchannel. Whenever a mobile station reads its assigned PCH Subchannel and determines that there is no message addressed to its mobile station identification number (MSID), it reads a PCON bit that is carried in the PCH Subchannel. If the PCON bit is set to 0, for example, the mobile station may sleep until the next occurrence of its assigned PCH Subchannel in the next primary Superframe. On the other hand, when the base station sets PCON equal to 1, i.e., when the base station activates PCH Continuation, the mobile station responds by reading additional point-to-point messaging slots, as determined by a PCH -- DISPLACEMENT parameter sent on the BCCH. When PCH Continuation is activated on a full-rate digital control channel, the mobile station reads every other point-to-point messaging slot after its assigned PCH Subchannel until a number of additional point-to-point messaging slots equal to the PCH -- DISPLACEMENT parameter have been read or until it reads a page message addressed to its mobile station identification (MSID) number. When a mobile station has read the last point-to-point messaging slot in the primary Superframe and the number of slots equal to the PCH -- DISPLACEMENT parameter still have not yet been read, the mobile station continues reading slots beginning with the second point-to-point messaging channel slot in the next primary Superframe. Similarly, if a mobile station has read the second to last point-to-point slot in a primary Superframe and the number of slots equal to the PCH -- DISPLACEMENT parameter still have not been read, the mobile station continues reading slots beginning with the first point-to-point messaging slot in the next primary Superframe. When PCH Continuation is activated on a half-rate digital control channel, the mobile station operates as it does on a full-rate digital control channel, except that instead of reading every other slot in the point-to-point messaging channel, it reads every point-to-point messaging slot after its assigned PCH Subchannel. The reading of every point-to-point messaging slot continues until the number of slots equal to the PCH -- DISPLACEMENT parameter has been read or until the mobile station receives a page message addressed to its mobile station identification (MSID). Point-to-point message continuation is the process by which the base station sends a message over multiple point-to-point messaging slots. A mobile station responds to point-to-point messaging channel message continuation whenever it determines that a message addressed to its mobile station identification (MSID) number, sent by the base station, occupies more than one point-to-point messaging slot. A page message spanning more than 1 point-to-point messaging slot, when sent on a full-rate digital control channel, is transmitted using every other point-to-point messaging slot. A page message spanning more than 1 point-to-point messaging slot, when sent on a half-rate digital control channel, is transmitted using consecutive point-to-point messaging slots. A non-page message spanning more than 1 point-to-point messaging slot is transmitted using consecutive point-to-point messaging slots unless interrupted. SUMMARY OF THE INVENTION The present invention advantageously addresses the needs above as well as other needs by providing a method of ensuring bandwidth availability in a point-to-point messaging portion of a digital control channel in a communications system. The invention, in one embodiment, may be characterized as a method employing the steps of assembling a Superframe within a base station, and transmitting the Superframe from the base station to a radio unit. The Superframe is divided into a plurality of slots. A broadcast control channel is defined as a first portion of the plurality of slots within the Superframe, and a point-to-point control channel is defined as a second portion of the plurality of slots. In accordance with this embodiment, the broadcast control channel has a Non-PCH Subchannel slot information element, e.g., two bits, that specifies a number, e.g., 0, 2, 4 or 6, of Non-PCH Subchannel slots, i.e., slots designed for Non-PCH Subchannel point-to-point messaging purposes, within the point-to-point control channel. The Non-PCH Subchannel slots are not available for use as PCH Subchannels (i.e., radio units cannot be hashed to Non-PCH Subchannel slots for purposes of receiving page messages or hard pages), but are available for non-page message traffic, PCH Continuation, point-to-point message continuation and the like. Thus, even in a system operating near or in excess of UPR maximum paging capacity, these Non-PCH Subchannel slots guarantee a minimum bandwidth for non-page messaging. Furthermore, because these Non-PCH Subchannel slots are, in a preferred embodiment, positioned at the end of the point-to-point messaging portion (or channel) of the primary Superframe, radio units having PCH Subchannels at or near the end of the Superframe that are undergoing PCH Continuation are less likely to be required to "look" into a subsequent primary Superframe to locate the PCH Continued message. As a result, such radio units realize a decreased delay in receiving PCH Continued messages, as well as a power savings (due to the fact that the receive channel and processor can be powered down after the primary Superframe, rather than having to wait to receive the remainder of the PCH Continued message in the subsequent primary Superframe). A further aspect of the invention, in at least some embodiments, is that a contiguous block of Non-PCH Subchannel slots is provided for multi-slot non-page messages. As a result, the need to use PCH Continuation to create contiguous blocks of slots for multi-slot non-page messages is greatly reduced or eliminated. Thus, efficiency of message transmission is improved and "awake," i.e. active or powered up, time for the receive channel and/or processor of the radio unit can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS The above and other aspects and features of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: FIG. 1 is a block diagram of a cellular communications system suitable for implementing one embodiment of the present invention; FIG. 2 is a block diagram of a base station controller as shown in FIG. 1; FIG. 3 is a block diagram of a cellular mobile unit with which one embodiment of the present invention can be utilized; FIG. 4 is a block diagram showing various elements in a time division multiple access digital control channel such as is used by the base station and mobile station of FIGS. 1-3; FIG. 5 is a block diagram illustrating an example of PCH Continuation in the digital control channel in accordance with the prior art; FIG. 6 is a block diagram illustrating an example of point-to-point messaging channel message continuation in the digital control channel of FIG. 5 in accordance with the prior art; FIG. 7 is a block diagram illustrating an example of PCH Continuation in the digital control channel of FIG. 5 in accordance with an embodiment of the present invention; and FIG. 8 is a block diagram illustrating an example of point-to-point message continuation in the digital control channel of FIG. 5 in accordance with another embodiment of the present invention. Corresponding reference characters indicate corresponding components throughout the several views of the drawings. DETAILED DESCRIPTION OF THE INVENTION The following description of the presently contemplated best mode of practicing the invention is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. Referring to FIG. 1, a block diagram is shown of a cellular communications system suitable for implementing one embodiment of the present invention. A cellular telephone system 10 has a plurality of mobile switching centers (MSC) 12, 14, 16, or mobile telephone switching offices (MTSO), that are connected to each other and to a public switched telephone network (PSTN) 18. Each of the mobile switching centers is connected to a respective group of base station controllers (BSC) 20, 22, 24. Each base station controller is connected to a group of individual base transceiver stations (BTS) 26, 28, 30. Each base transceiver station of the groups 26, 28, 30 defines an individual cell of the cellular telephone system. Each base transceiver station of the groups 26, 28, 30 includes hardware and software functions required to communicate over communications channels of the system 10; and includes transmitters and receivers for communication with mobile telephone units. Each base transceiver station 26, 28, 30 also includes a plurality of individual standard receivers (StdR) 31 and scanning receivers (SR) 32 (for scanning selected portions of the communications channel). Each base transceiver station 26, 28, 30 further includes digital multiplex equipment for transmission of audio traffic to its associated base station controller. It is the base transceiver stations 26, 28, 30, along with their associated base station controllers 20, 22, 24 and mobile switching centers, that perform the steps described herein in order to carry out one embodiment of the invention. A plurality of digital mobile telephone units 33 are used with the system 10 for communication over the communications channel (or radio frequency traffic channel) with a particular base transceiver station of a particular cell in which the particular base transceiver station is located. Associated with each digital mobile unit 33 is a scanning receiver 35 for scanning selected portions of the communications channel between the mobile unit 33 and the base transceiver station of serving and neighboring cells. Each base station controller of the groups 20, 22, 24 implements audio compression/decompression, handles call establishment, disconnect, and handoff procedures, and allocates system resources between the individual base transceiver stations 26, 28, 30 associated with each of the base station controllers 20, 22, 24. More specifically, each base station controller performs handoff execution for transferring on-going communications from one cell to another within the group of base transceiver stations connected to the particular base station controller. Each base station controller communicates with its associated mobile switching center for effecting a handoff involving a cell or base transceiver station associated with a different base station controller. Each mobile switching center 12, 14, 16 processes all requests for calls, switching functions, as well as the mobility functions of registration, authentication and handoff. Referring next to FIG. 2, a detailed block diagram is shown of an exemplary base station controller, representative of the base station controllers 20, 22, 24 in FIG. 1. (As will be understood by one skilled in the art, a similar block diagram representation can be made of the mobile units of the present embodiment). The base station controller 20, 22, 24 includes trunk interfaces 34 to its associated mobile switching center and trunk interfaces 36 to its associated base transceiver stations. In one particular implementation of the present embodiment, each base station controller includes a switching and transcoding module (STM) 37, and is made up of three types of control processors implemented in identical hardware modules 38, 40, 42. A first of the hardware modules is a call control processor (CCP) 38. In addition to switching of pulse code modulation (PCM) traffic between the trunks 34, 36 for analog traffic, it terminates call protocol for mobile switching. It also performs connection control and mobility management for handoff execution. For digital configurations (in accordance with, e.g., IS-136) there can be more than one call control processor for each base station controller. When there is more than one call control processor per base station controller, calls are distributed among call control processors based upon load. The number of call control processors needed depends upon load and redundancy requirements. A second of the hardware modules is a channel access processor (CAP) 40, and is required for digital configurations, as described herein. The channel access processor 40 performs voice channel allocations and deallocations. The channel access processor 40 also forwards power and time alignment measurements to the call control processors 38. A third of the hardware modules is a global resource processor (GRP) 42 that distributes calls among the call control processors 38 based on load; and communicates with other base station controllers for scanning receiver measurements, i.e., the global resource processor 42 communicates with another base station controller to exchange messages relating to scanning receiver (SR) measurements. Referring to FIG. 3, a block diagram is shown of an exemplary cellular mobile unit, in which the teachings of the present invention can be utilized. A radio frequency (RF) unit 51 is shown coupled to an interface unit 52, which is in turn coupled to an application specific integrated circuit (ASIC) 53. As is well known in the art, the RF unit includes circuits that comprise a receive channel and circuits that comprise a transmit channel. Such receive channel and transmit channel are well known in the art of cellular telephony. The RF unit 51 can also be directly coupled to the application specific integrated circuit 53. A digital signal processor (DSP) 57 is coupled through a data bus 54 to a random access memory (RAM) 55, a read only memory (ROM) 56, and the application specific integrated circuit 53. The application specific integrated circuit 53 is also coupled to coder-decoders (CODECs) 58, which are coupled through an audio interface 59 to a microphone 68 and a speaker 62. The RF unit 51 of the cellular mobile unit of FIG. 3 performs conventional radio frequency communications, as are known in the art. The interface unit 52 performs digital to analog conversions, analog to digital conversions, filtering and wave shaping, as dictated by the RF unit 51 and the application specific integrated circuit 53. The application specific integrated circuit 53 is used to implement an FM frequency shift keying (FSK) receiver, an FM message processor, transmit and receive timing generators, interfaces to the CODECs 58, buffering of received samples, fade detection circuitry, FEC encoding and decoding, a fixed point divider unit (for VSELP), a phase lock loop (for generation of a CODEC clock), miscellaneous input/output circuitry, and glue logic for processor interfaces. The digital signal processor (DSP) 57 is utilized within the cellular transceiver to perform the following functions: π/4 DQPSK modulation/demodulation, VSELP analysis/synthesis, hands-free voice switching, demodulation/equalization, FM audio transmission/reception, FM SAT detection and generation, FM FSK transmission, FM message handling/call processing, digital call processing/control, user interface, monitor/diagnostic/testing, SACCH encoding/decoding/queuing, authentication and key generation, signaling privacy, voice recognition, and voice response. The read only memory (ROM) 56 is used for storage of control software as well as RAM-based overlay code. The read only memory 56 may include an electronically erasable programmable read only memory (EEPROM) (not shown) that can be used for storage of ESN/user information and factory calibration settings. The random access memory (RAM) 56 is used for data storage and program memory overlays. The coder/decoders (CODECs) 58 are used for modulation and wave shaping of transmitted and received signals, as is known in the art. The audio interface 59 includes a linear coder/decoder for voice samples and other interfaces such as filters and multiplexers for interfacing to the microphone 62 and speaker 68. Referring next to FIG. 4, a block diagram is shown of the various elements in a time division multiple access digital control channel. A TDMA Frame 100 is depicted made up of six Slots 102, 104, 106, 108, 110, 112. Each Slot 102, 104, 106, 108, 110, 112 is transmitted through the communications channel, consisting primarily of air, during a 6.67 mS period of time, such that the TDMA Frame 100 is 40 mS in duration. In accordance with current TDMA conventions, a TDMA Channel is made up of every third slot within the TDMA Frame. Thus, Slots 1 and 4 (102, 108) are a part of one TDMA channel, Slots 2 and 5 (104, 110) part of another TDMA channel, and Slots 3 and 6 (106, 112) yet another. Within each TDMA channel, groups of 32 TDMA blocks (and thus 32 slots) comprise a Superframe 114, having a duration of 640 mS. A total of three Superframes, one per TDMA channel, are transmitted every 640 mS. Within each Superframe 114, a portion of the slots are designated the Broadcast Channel (BCCH), another portion Reserved, and another portion point-to-point messaging channel. Each mobile unit monitoring a particular base station is assigned to monitor a particular PCH Subchannel, i.e., a particular slot within the point-to-point messaging channel. As an example, slot 24 (116) may be the monitored PCH Subchannel for a particular group of mobile units within a cell (assuming for a given case slot 24 is part of the point-to-point messaging channel). The PCH Subchannel may contain any of a plurality of point-to-point communications encoded in 324 bits, which make up the PCH Subchannel. Referring next to FIG. 5, a block diagram is shown of an example of PCH Continuation in a digital control channel of the prior art. In the example shown, PCH Continuation activation occurs on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to Superframe Phase (SFP)=27, (i.e., slot 27). In the event the mobile station determines that there is no message addressed to its MSID in its PCH Subchannel, (i.e., slot 27), a PCON bit (i.e., page continuation bit) equals 1 and the base station has set a variable referred to as PCH -- DISPLACEMENT to 4, the mobile station proceeds to read every other point-to-point messaging slot starting with the point-to-point messaging slot corresponding to SFP=29 (i.e., slot 29) in the first primary Superframe. If slot 29 is read without receiving a message addressed to the mobile station, the mobile station continues to read every other point-to-point messaging slot with SFP=31, i.e., slot 31. If slots 29 and 31 are read without receiving a message addressed to the mobile station, the mobile station continues to read point-to-point messaging slots corresponding to SFP=n+1 and n+3, i.e., the second and fourth point-to-point messaging slots in the second primary Superframe. In the event these slots are read without receiving a message addressed to its MSID, at the point where an additional number of slots equal to the set PCH -- DISPLACEMENT have been read, the mobile station sleeps until the next occurrence of its assigned PCH Subchannel. Unfortunately, in accordance with the prior art system illustrated, in order to read all of the slots in which a page for the mobile station might appear, the mobile station either remains active during the entire secondary Superframe and the broadcast control channel of the second primary Superframe, or deactivates its receive channel during the secondary Superframe and broadcast control channel, keeping its processor awake. This amounts to more than 640 mS of additional actuation time during which the mobile station's processor, and possibly its receive channel, must remain active, i.e., turned on. Furthermore, and perhaps more importantly, this also represents a significant delay in reading the slots in which a page message might appear, and a significant inefficiency in the processing of page messages. Referring next to FIG. 6, a block diagram is shown of an example of point-to-point messaging channel message continuation in a digital control channel in accordance with the prior art. Point-to-point messaging channel message continuation activation is shown on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=27, i.e., slot 27. In the example shown, when the mobile station determines that there is no message addressed to its MSID in its assigned PCH Subchannel, and when the PCON bit is set to 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read every other point-to-point messaging channel slot starting with the slot corresponding to SFP=29, i.e., slot 29. In the present example, the radio unit receives, in slot 29, the first slot of a three point-to-point messaging slot page message addressed to its MSID. The mobile station next reads the point-to-point messaging slots corresponding to SFP=31 (i.e., slot 31) and SFP=n+1 (i.e., slot 5 in the next primary Superframe), which contains the remainder of the page message. Note that in accordance with another example, the mobile station determines that there is a message addressed to its MSID in its assigned PCH Subchannel, and the base station has set PCH -- DISPLACEMENT to 4. In this other example, the radio unit receives, in slot 27, the first slot of a four point-to-point messaging slot page message addressed to its MSID. The mobile station proceeds to read every other point-to-point messaging channel slot starting with the slot corresponding to SFP=29 and ending with the slot corresponding to SFP=n+1, as described in the preceding example. In accordance with this other example, the PCON bit is irrelevant. Point-to-point messaging channel message continuation may also be used when a non-page message requiring more than one point-to-point messaging slot (i.e., a multi-slot non-page message) is sent. In this case, the PCON bit is not a factor, i.e., is irrelevant, and the number of additional slots read will be a function of the type of multi-slot point-to-point message being sent, as opposed to a function of PCH -- DISPLACEMENT. Advantageously, the present embodiment thus effectively increases the bandwidth available for non-page messages, essentially without sacrificing the bandwidth available for page messages or hard pages (because, in accordance with, e.g., IS-136, multiple pages can be transmitted in a single slot using hard pages instead of page messages, which generally only carry a single page per slot). As an example, if there are 25 point-to-point messaging slots in a digital control channel, and all 25 are PCH Subchannel slots, when 25 mobile stations are to be paged, all 25 point-to-point messaging slots may be used for transmitting page messages, leaving no slots for non-page messages. If, however, four of the 25 slots are designated as Non-PCH Subchannel slots, in accordance with an example of the present embodiment, then the 25 mobile stations are paged in the 21 available PCH Subchannel slots--with some of the PCH Subchannel slots containing hard pages for paging up to three mobile stations in a single slot. In this way, the four Non-PCH Subchannel slots are left for carrying non-page messages (or for PCH Continuation or point-to-point messaging channel message continuation, as described herein below). Unfortunately, in accordance with the prior art system illustrated, in order to read all of the slots of the continued message, the mobile station may be required to maintain its receive channel in an active state and will be required to maintain its processor in an active state, not only during the slots to be read, but also during the entire secondary Superframe and the broadcast control channel of the second primary Superframe. This amounts to more than 640 mS of additional activation time during which the mobile station's processor and possibly receive channel, must remain active and, in addition, more than 640 ms of delay in receiving the continued message. Thus, as can be seen in FIGS. 5 and 6, significant additional activation time for the mobile station's processor, and possibly receive channel, and a significant delay in receiving point-to-point messages results when PCH Continuation or point-to-point messaging channel message continuation activation occurs on a full-rate digital control channel. Such increased activation and delay, however, tends to have a greater impact on those mobile stations that happen to be assigned to a PCH Subchannel that is at or near the end of the primary Superframe. Those mobile stations assigned to a PCH Subchannel earlier in the primary Superframe, e.g., corresponding to, e.g., SFP=11 (i.e., slot 11) generally will not be required to maintain their receive channels and/or processors in an active state during the secondary Superframe, because there will generally be a sufficient number of PCH Subchannels available following the assigned PCH Subchannel to fulfill the needs of PCH Continuation (FIG. 5) or point-to-point messaging channel message continuation (FIG. 6) activation. Problematically, mobile stations are not randomly assigned to their PCH Subchannel, but rather the PCH Subchannel is assigned based on a hash involving the mobile station identification number (MIN), and the available number of PCH Subchannels in the point-to-point messaging channel. Therefore, because the mobile station identification number and the number of slots in the point-to-point messaging channel of a particular base station are not likely to change very often, the mobile stations hashed to PCH Subchannels late (i.e., near the end, or to the right as oriented in FIGS. 5 and 6) in the primary Superframe are, over time, likely to be required to maintain their receive channels and/or processors in an active state for longer periods of time than those mobile stations having been assigned a PCH Subchannel earlier in the primary Superframe and are likely to experience greater delays in receiving pages and point-to-point messages. As a result, the mobile stations with PCH Subchannels late in the primary Superframe will tend to experience a higher power usage, and therefore a reduced battery life (due to the increased activation of their receive channels), and slower performance as compared with those mobile stations having a PCH Subchannel earlier in the primary Superframe. As a result, some subscribers to the cellular telephone system will, by virtue of their assigned mobile station identification numbers, receive inferior power consumption/battery life characteristics, and performance characteristics from their mobile stations. The present embodiment provides for a Non-PCH Subchannel slot information element in the broadcast control channel of each Superframe. The Non-PCH Subchannel slot information element uses two bits to specify the number of Non-PCH Subchannel slots within the point-to-point messaging channel. By way of example, in a full rate digital control channel, if the Non-PCH Subchannel slot information element is set to 00, all point-to-point messaging slots are eligible to be allocated as PCH Subchannels. If the Non-PCH Subchannel slot information element is set to 01, the last two point-to-point messaging slots cannot be allocated as PCH Subchannels, if the Non-PCH Subchannel slot information element is set to 10, the last four cannot be allocated as PCH Subchannels, and if the Non-PCH Subchannel slot information element is set to 11, the last six cannot be allocated as PCH Subchannels. In a half-rate digital control channel, the above Non-PCH Subchannel slot information element setting signify a reservation of zero slots, the last slot, the last two slots and the last three slots in the point-to-point messaging channel, respectively. Once slots are reserved through the Non-PCH Subchannel slot information element, they cannot be allocated as PCH Subchannels, i.e., they cannot be hashed to by mobile stations and by the base station when determining the appropriate PCH Subchannel to monitor for pages, or in which to transmit a page for a particular mobile station, respectively. They can, however, be used as additional slots for point-to-point messaging channel message continuation or PCH Continuation or for other non-page message traffic, such as access response and short message service (SMS) messages. Thus, when paging traffic increases within the point-to-point messaging channel, e.g., nearing 100% of UPR maximum paging capacity, or more, the number of slots designated in the Non-PCH Subchannel slot information element are, unlike in prior art systems, still available for the transmission of non-page messages. For example, as illustrated below in FIGS. 7 and 8, these Non-PCH Subchannel slots are available for point-to-point messaging channel message continuation and PCH Continuation, as well as for other non-page message traffic. Referring next to FIG. 7, a block diagram is shown illustrating an example of PCH Continuation in a digital control channel wherein an embodiment of the present invention is utilized to minimize the amount of activation of a mobile station's receive channel needed. PCH Continuation activation is illustrated as occurring on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=21 (i.e., slot 21). In the event the mobile station determines that there is no message addressed to its mobile station identification number in its PCH Subchannel (i.e., slot 27), when the PCON bit equals 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read point-to-point messaging slots corresponding to SFP=23, 25, 27 and 29 (i.e., slots 23, 25, 27 and 29--a number of slots equal to PCH -- DISPLACEMENT) in the first primary Superframe. Note that in the illustrated example, slots 26 through 31 of the point-to-point messaging channel are reserved for non-page messages, and therefore are not hashed to by mobile stations when determining their PCH Subchannel. (Note that the phrase "reserved for non-page messages" does not mean that such slots cannot be used for page messages, but merely that such slots are not hashed to by any mobile station when determining PCH Subchannel assignments. Such slots in accordance with the present embodiment, therefore, can only be read in response to PCH Continuation, point-to-point messaging channel message continuation, or when scanning for non-page point-to-point messages.) As a result, when the mobile station looks beyond its PCH Subchannel (as occurs in PCH Continuation and point-to-point messaging channel message continuation, or when the mobile station is searching for non-page point-to-point messages) there are, in this example, six Non-PCH Subchannel slots available after the last assigned PCH Subchannel for PCH Continuation, point-to-point messaging channel message continuation Message Continuation or non-page point-to-point messages. One result of having these Non-PCH Subchannel slots is that mobile stations with PCH subchannels late in the primary Superframe's point-to-point messaging channel are much less likely to have to maintain their processors and receive channels and/or processors in an active state through the secondary Superframe and into the next primary Superframe in order to receive PCH displaced pages or continued point-to-point messaging channel messages. A further result of having these Non-PCH subchannel slots is that these mobile stations with PCH subchannels late in the primary Superframe's point-to-point messaging channel are much less likely to experience delays caused by these PCH Continuation, point-to-point messaging channel message continuation or other multi-slot point-to-point messages that require slots in a subsequent Superframe. Another result is that there are always a few slots available for other non-page messages, such as access response messages (e.g., registration acceptance) or SMS messages, even in environments where pages greatly exceed UPR maximum paging capacity. Thus, the increased power consumption and decreased battery life, delays in message reception and reduced non-page message throughput, heretofore experienced by these mobile stations, is significantly reduced or eliminated by the present embodiment. Referring next to FIG. 8, a block diagram is shown illustrating an example of point-to-point messaging channel message continuation in the digital control channel in accordance with another embodiment of the invention. Point-to-point messaging channel message continuation activation on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=21, (i.e., slot 21) is shown. When the mobile station determines that there is no message addressed to its MSID in the assigned PCH Subchannel, and when the PCON bit is set to 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read the point-to-point messaging slot corresponding to SFP=23, (i.e., slot 23) and receives in such slot the first slot of a three point-to-point messaging slot page message addressed to its MSID. The mobile station next reads the point-to-point messaging slots corresponding to SFP=31 (i.e., slot 31), SFP=25 (i.e., slot 25) and SFP=27 (i.e., slot 27) in the primary Superframe. As with the example described above in FIG. 7, it can be seen that in the present embodiment, mobile stations having assigned (i.e., hashed) to them a PCH Subchannel late in the group of subchannels within the point-to-point messaging channel are able to receive a three slot point-to-point messaging channel message that has been continued from its assigned PCH Subchannel. Unlike in heretofore known cellular telephone systems, as described above in FIG. 6, the present embodiment eliminates or substantially reduces the need for these mobile stations having assigned PCH Subchannels late in the point-to-point messaging channel to maintain their receive channels and/or processors in an active state during the secondary Superframe and into the next primary Superframe (as illustrated in FIG. 6); and substantially improves the performance of these mobile station by eliminating delays in the reception of non-page messages due to their spanning more than one Superframe. While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.
A method of ensuring bandwidth availability for non-page point-to-point traffic in a communications system employs the steps of assembling a Superframe within a base station, and transmitting the Superframe from the base station to a radio unit. The Superframe is divided into a plurality of slots. A broadcast control channel is defined as a first portion of the plurality, and a point-to-point control channel is defined as a second portion of the plurality. The broadcast control channel has a Non-PCH Subchannel slot information element specifying a number of Non-PCH Subchannel slots within the point-to-point control channel.
Concisely explain the essential features and purpose of the invention.
[ "BACKGROUND OF THE INVENTION The present invention relates to ensuring bandwidth availability in a communications system, and more particularly to ensuring such bandwidth availability in a communications system.", "Even more particularly, the present invention relates to ensuring bandwidth availability in a point-to-point messaging portion of a digital control channel in a communications system.", "Interim Standard (IS) 136 (promulgated by the Telecommunications Industry Association) adds a Digital Control Channel (DCCH) to IS-54B, an 800 MHZ TDMA Cellular Standard.", "The fundamental unit of measure in the digital control channel is a slot.", "Slots are logically combined (in groups of 16 for a half-rate digital control channel and 32 for a full-rate digital control channel) to form "Superframes".", "Of the slots in a Superframe available for signaling, some are designated by the base station (BMI) for broadcast (point-to-multipoint) messaging and the rest for point-to-point messaging.", "In order for the base station to be able to notify (or "page") a mobile station (MS) of an incoming call (or other impending transaction), the mobile station is assigned to one and only one of the slots in a Superframe available for point-to-point messaging on the forward digital control channel (i.e., that portion of the digital control channel used to transmit messages from the base station to the mobile station).", "Note that the term mobile station is used herein to refer to a radio unit in a communications system, and is not limited to being "mobile.", """, "The term "mobile"", "unit is used herein merely because of its wide (and perhaps unfortunate) acceptance and clear meaning in the communications arts, which includes radio units that are "stationary"", "or "fixed".", "When the base station needs to "page"", "the mobile station, i.e., notify the mobile station that it has an incoming call (or other impending transaction), the base station transmits a "page message"", "or a "hard page"", "in the assigned slot.", "(An advantageous approach to utilizing "hard pages"", "is described in U.S. patent pending application Ser.", "No. 08/394,091, entitled OPTIMAL PAGING OF ONE OR TWO MOBILE STATIONS USING A HARD PAGE SLOT, commonly invented and assigned with the present patent document, incorporated herein by reference.) Under quiescent conditions, the mobile station need only monitor this assigned slot in the Superframe.", "Thus, the mobile station is able to "sleep"", "while the other 31 slots of the Superframe are being transmitted.", "In addition, because every other Superframe transmitted (i.e., every primary Superframe) by the base station is followed by a Superframe (secondary Superframe) having identical point-to-point paging slots, the mobile unit can sleep during every other entire Superframe.", "For other types of point-to-point traffic, however, the mobile station is not assigned to a specific slot in a Superframe;", "rather, when it is expecting a "non-page message,"", "i.e., not a message intended to notify the mobile station of an incoming call (or other impending transaction), from the base station, the mobile station is required to search for non-page messages addressed to itself in each slot available for point-to-point messaging within the Superframe.", "Currently, mobile stations are hashed to a slot in the Superframe (called a PCH Subchannel) where the mobile station it expects to receive page traffic.", "Nominally, the mobile station is required to read this same slot in every other Superframe.", "For illustration purposes, assume a minimal full-rate digital control channel containing four broadcast control channel (BCCH) slots and no Reserved slots.", "Hence, there are 28 point-to-point message slots, i.e., point-to-point messaging channel slots available for paging (i.e., available for use as PCH Subchannels.) If only 10% of the UPR maximum paging capacity (i.e., User Performance Requirements maximum paging capacity, which is defined as 373,000 pages/hour, or 14 pages/hyperframe by C.T.I.A.) is assumed, then up to one-half of the available point-to-point messaging channel bandwidth could be dedicated to paging.", "As either the paging traffic increases or the number of point-to-point messaging slots decrease (due to, e.g., additional BCCH messaging), the ratio of pages to PCH Subchannels can approach or exceed 1:1.", "The consequence of an increase in paging traffic or corresponding decrease in point-to-point messaging channel bandwidth is that the number of slots available for other messages (e.g., non-page messages) is reduced, and consecutive slots for multi-slot messages become scarce.", "(The term multi-slot message, as used herein, refers to a page message or a non-page message that spans more than one point-to-point messaging channel slot.) Thus throughput of multi-slot messages and non-page messages may be decreased as paging traffic increases, causing delay in the transmission of such messages.", "As used herein, the terms "page message"", "and "hard page"", "refers to one or more slots of data transmitted from a base station over the point-to-point messaging channel that contains information intended to signal one (or possibly more) of a plurality of transceiver units that such transceiver unit(s) have an incoming call.", "(An incoming call can be, e.g., a voice call or any other type of incoming call capable of being serviced by the base station and transceiver units.) The term "non-page message"", "refers to any slots of data transmitted over the point-to-point messaging channel that are not "page messages"", "or "hard pages.", """, "Since IS-136 provides for multi-page PCH frames (meaning that more than one mobile station may be paged in a single PCH Subchannel), the volume of available PCH Subchannels, i.e., point-to-point messaging slots assignable as PCH Subchannels, is not a primary issue.", "However, to compensate for the decrease in bandwidth available for single and multi-slot non-page point-to-point message traffic, the base station must increasingly rely on a technique known as "PCH Continuation"", "to open up gaps into which this non-page point-to-point message traffic can be accommodated.", "In a worst case scenario, pages must be delayed, i.e., displaced into later slots, in order to allow some minimal bandwidth for non-page point-to-point message traffic.", "Such delay, when it affects pages destined for PCH Subchannels late in the primary Superframe, may result in such pages being delayed into a subsequent primary Superframe.", "PCH Continuation (PCON) is the process by which the base station directs a mobile station to continue reading a number of point-to-point messaging slots after it first reads its assigned PCH Subchannel.", "Whenever a mobile station reads its assigned PCH Subchannel and determines that there is no message addressed to its mobile station identification number (MSID), it reads a PCON bit that is carried in the PCH Subchannel.", "If the PCON bit is set to 0, for example, the mobile station may sleep until the next occurrence of its assigned PCH Subchannel in the next primary Superframe.", "On the other hand, when the base station sets PCON equal to 1, i.e., when the base station activates PCH Continuation, the mobile station responds by reading additional point-to-point messaging slots, as determined by a PCH -- DISPLACEMENT parameter sent on the BCCH.", "When PCH Continuation is activated on a full-rate digital control channel, the mobile station reads every other point-to-point messaging slot after its assigned PCH Subchannel until a number of additional point-to-point messaging slots equal to the PCH -- DISPLACEMENT parameter have been read or until it reads a page message addressed to its mobile station identification (MSID) number.", "When a mobile station has read the last point-to-point messaging slot in the primary Superframe and the number of slots equal to the PCH -- DISPLACEMENT parameter still have not yet been read, the mobile station continues reading slots beginning with the second point-to-point messaging channel slot in the next primary Superframe.", "Similarly, if a mobile station has read the second to last point-to-point slot in a primary Superframe and the number of slots equal to the PCH -- DISPLACEMENT parameter still have not been read, the mobile station continues reading slots beginning with the first point-to-point messaging slot in the next primary Superframe.", "When PCH Continuation is activated on a half-rate digital control channel, the mobile station operates as it does on a full-rate digital control channel, except that instead of reading every other slot in the point-to-point messaging channel, it reads every point-to-point messaging slot after its assigned PCH Subchannel.", "The reading of every point-to-point messaging slot continues until the number of slots equal to the PCH -- DISPLACEMENT parameter has been read or until the mobile station receives a page message addressed to its mobile station identification (MSID).", "Point-to-point message continuation is the process by which the base station sends a message over multiple point-to-point messaging slots.", "A mobile station responds to point-to-point messaging channel message continuation whenever it determines that a message addressed to its mobile station identification (MSID) number, sent by the base station, occupies more than one point-to-point messaging slot.", "A page message spanning more than 1 point-to-point messaging slot, when sent on a full-rate digital control channel, is transmitted using every other point-to-point messaging slot.", "A page message spanning more than 1 point-to-point messaging slot, when sent on a half-rate digital control channel, is transmitted using consecutive point-to-point messaging slots.", "A non-page message spanning more than 1 point-to-point messaging slot is transmitted using consecutive point-to-point messaging slots unless interrupted.", "SUMMARY OF THE INVENTION The present invention advantageously addresses the needs above as well as other needs by providing a method of ensuring bandwidth availability in a point-to-point messaging portion of a digital control channel in a communications system.", "The invention, in one embodiment, may be characterized as a method employing the steps of assembling a Superframe within a base station, and transmitting the Superframe from the base station to a radio unit.", "The Superframe is divided into a plurality of slots.", "A broadcast control channel is defined as a first portion of the plurality of slots within the Superframe, and a point-to-point control channel is defined as a second portion of the plurality of slots.", "In accordance with this embodiment, the broadcast control channel has a Non-PCH Subchannel slot information element, e.g., two bits, that specifies a number, e.g., 0, 2, 4 or 6, of Non-PCH Subchannel slots, i.e., slots designed for Non-PCH Subchannel point-to-point messaging purposes, within the point-to-point control channel.", "The Non-PCH Subchannel slots are not available for use as PCH Subchannels (i.e., radio units cannot be hashed to Non-PCH Subchannel slots for purposes of receiving page messages or hard pages), but are available for non-page message traffic, PCH Continuation, point-to-point message continuation and the like.", "Thus, even in a system operating near or in excess of UPR maximum paging capacity, these Non-PCH Subchannel slots guarantee a minimum bandwidth for non-page messaging.", "Furthermore, because these Non-PCH Subchannel slots are, in a preferred embodiment, positioned at the end of the point-to-point messaging portion (or channel) of the primary Superframe, radio units having PCH Subchannels at or near the end of the Superframe that are undergoing PCH Continuation are less likely to be required to "look"", "into a subsequent primary Superframe to locate the PCH Continued message.", "As a result, such radio units realize a decreased delay in receiving PCH Continued messages, as well as a power savings (due to the fact that the receive channel and processor can be powered down after the primary Superframe, rather than having to wait to receive the remainder of the PCH Continued message in the subsequent primary Superframe).", "A further aspect of the invention, in at least some embodiments, is that a contiguous block of Non-PCH Subchannel slots is provided for multi-slot non-page messages.", "As a result, the need to use PCH Continuation to create contiguous blocks of slots for multi-slot non-page messages is greatly reduced or eliminated.", "Thus, efficiency of message transmission is improved and "awake,"", "i.e. active or powered up, time for the receive channel and/or processor of the radio unit can be minimized.", "BRIEF DESCRIPTION OF THE DRAWINGS The above and other aspects and features of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: FIG. 1 is a block diagram of a cellular communications system suitable for implementing one embodiment of the present invention;", "FIG. 2 is a block diagram of a base station controller as shown in FIG. 1;", "FIG. 3 is a block diagram of a cellular mobile unit with which one embodiment of the present invention can be utilized;", "FIG. 4 is a block diagram showing various elements in a time division multiple access digital control channel such as is used by the base station and mobile station of FIGS. 1-3;", "FIG. 5 is a block diagram illustrating an example of PCH Continuation in the digital control channel in accordance with the prior art;", "FIG. 6 is a block diagram illustrating an example of point-to-point messaging channel message continuation in the digital control channel of FIG. 5 in accordance with the prior art;", "FIG. 7 is a block diagram illustrating an example of PCH Continuation in the digital control channel of FIG. 5 in accordance with an embodiment of the present invention;", "and FIG. 8 is a block diagram illustrating an example of point-to-point message continuation in the digital control channel of FIG. 5 in accordance with another embodiment of the present invention.", "Corresponding reference characters indicate corresponding components throughout the several views of the drawings.", "DETAILED DESCRIPTION OF THE INVENTION The following description of the presently contemplated best mode of practicing the invention is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention.", "The scope of the invention should be determined with reference to the claims.", "Referring to FIG. 1, a block diagram is shown of a cellular communications system suitable for implementing one embodiment of the present invention.", "A cellular telephone system 10 has a plurality of mobile switching centers (MSC) 12, 14, 16, or mobile telephone switching offices (MTSO), that are connected to each other and to a public switched telephone network (PSTN) 18.", "Each of the mobile switching centers is connected to a respective group of base station controllers (BSC) 20, 22, 24.", "Each base station controller is connected to a group of individual base transceiver stations (BTS) 26, 28, 30.", "Each base transceiver station of the groups 26, 28, 30 defines an individual cell of the cellular telephone system.", "Each base transceiver station of the groups 26, 28, 30 includes hardware and software functions required to communicate over communications channels of the system 10;", "and includes transmitters and receivers for communication with mobile telephone units.", "Each base transceiver station 26, 28, 30 also includes a plurality of individual standard receivers (StdR) 31 and scanning receivers (SR) 32 (for scanning selected portions of the communications channel).", "Each base transceiver station 26, 28, 30 further includes digital multiplex equipment for transmission of audio traffic to its associated base station controller.", "It is the base transceiver stations 26, 28, 30, along with their associated base station controllers 20, 22, 24 and mobile switching centers, that perform the steps described herein in order to carry out one embodiment of the invention.", "A plurality of digital mobile telephone units 33 are used with the system 10 for communication over the communications channel (or radio frequency traffic channel) with a particular base transceiver station of a particular cell in which the particular base transceiver station is located.", "Associated with each digital mobile unit 33 is a scanning receiver 35 for scanning selected portions of the communications channel between the mobile unit 33 and the base transceiver station of serving and neighboring cells.", "Each base station controller of the groups 20, 22, 24 implements audio compression/decompression, handles call establishment, disconnect, and handoff procedures, and allocates system resources between the individual base transceiver stations 26, 28, 30 associated with each of the base station controllers 20, 22, 24.", "More specifically, each base station controller performs handoff execution for transferring on-going communications from one cell to another within the group of base transceiver stations connected to the particular base station controller.", "Each base station controller communicates with its associated mobile switching center for effecting a handoff involving a cell or base transceiver station associated with a different base station controller.", "Each mobile switching center 12, 14, 16 processes all requests for calls, switching functions, as well as the mobility functions of registration, authentication and handoff.", "Referring next to FIG. 2, a detailed block diagram is shown of an exemplary base station controller, representative of the base station controllers 20, 22, 24 in FIG. 1. (As will be understood by one skilled in the art, a similar block diagram representation can be made of the mobile units of the present embodiment).", "The base station controller 20, 22, 24 includes trunk interfaces 34 to its associated mobile switching center and trunk interfaces 36 to its associated base transceiver stations.", "In one particular implementation of the present embodiment, each base station controller includes a switching and transcoding module (STM) 37, and is made up of three types of control processors implemented in identical hardware modules 38, 40, 42.", "A first of the hardware modules is a call control processor (CCP) 38.", "In addition to switching of pulse code modulation (PCM) traffic between the trunks 34, 36 for analog traffic, it terminates call protocol for mobile switching.", "It also performs connection control and mobility management for handoff execution.", "For digital configurations (in accordance with, e.g., IS-136) there can be more than one call control processor for each base station controller.", "When there is more than one call control processor per base station controller, calls are distributed among call control processors based upon load.", "The number of call control processors needed depends upon load and redundancy requirements.", "A second of the hardware modules is a channel access processor (CAP) 40, and is required for digital configurations, as described herein.", "The channel access processor 40 performs voice channel allocations and deallocations.", "The channel access processor 40 also forwards power and time alignment measurements to the call control processors 38.", "A third of the hardware modules is a global resource processor (GRP) 42 that distributes calls among the call control processors 38 based on load;", "and communicates with other base station controllers for scanning receiver measurements, i.e., the global resource processor 42 communicates with another base station controller to exchange messages relating to scanning receiver (SR) measurements.", "Referring to FIG. 3, a block diagram is shown of an exemplary cellular mobile unit, in which the teachings of the present invention can be utilized.", "A radio frequency (RF) unit 51 is shown coupled to an interface unit 52, which is in turn coupled to an application specific integrated circuit (ASIC) 53.", "As is well known in the art, the RF unit includes circuits that comprise a receive channel and circuits that comprise a transmit channel.", "Such receive channel and transmit channel are well known in the art of cellular telephony.", "The RF unit 51 can also be directly coupled to the application specific integrated circuit 53.", "A digital signal processor (DSP) 57 is coupled through a data bus 54 to a random access memory (RAM) 55, a read only memory (ROM) 56, and the application specific integrated circuit 53.", "The application specific integrated circuit 53 is also coupled to coder-decoders (CODECs) 58, which are coupled through an audio interface 59 to a microphone 68 and a speaker 62.", "The RF unit 51 of the cellular mobile unit of FIG. 3 performs conventional radio frequency communications, as are known in the art.", "The interface unit 52 performs digital to analog conversions, analog to digital conversions, filtering and wave shaping, as dictated by the RF unit 51 and the application specific integrated circuit 53.", "The application specific integrated circuit 53 is used to implement an FM frequency shift keying (FSK) receiver, an FM message processor, transmit and receive timing generators, interfaces to the CODECs 58, buffering of received samples, fade detection circuitry, FEC encoding and decoding, a fixed point divider unit (for VSELP), a phase lock loop (for generation of a CODEC clock), miscellaneous input/output circuitry, and glue logic for processor interfaces.", "The digital signal processor (DSP) 57 is utilized within the cellular transceiver to perform the following functions: π/4 DQPSK modulation/demodulation, VSELP analysis/synthesis, hands-free voice switching, demodulation/equalization, FM audio transmission/reception, FM SAT detection and generation, FM FSK transmission, FM message handling/call processing, digital call processing/control, user interface, monitor/diagnostic/testing, SACCH encoding/decoding/queuing, authentication and key generation, signaling privacy, voice recognition, and voice response.", "The read only memory (ROM) 56 is used for storage of control software as well as RAM-based overlay code.", "The read only memory 56 may include an electronically erasable programmable read only memory (EEPROM) (not shown) that can be used for storage of ESN/user information and factory calibration settings.", "The random access memory (RAM) 56 is used for data storage and program memory overlays.", "The coder/decoders (CODECs) 58 are used for modulation and wave shaping of transmitted and received signals, as is known in the art.", "The audio interface 59 includes a linear coder/decoder for voice samples and other interfaces such as filters and multiplexers for interfacing to the microphone 62 and speaker 68.", "Referring next to FIG. 4, a block diagram is shown of the various elements in a time division multiple access digital control channel.", "A TDMA Frame 100 is depicted made up of six Slots 102, 104, 106, 108, 110, 112.", "Each Slot 102, 104, 106, 108, 110, 112 is transmitted through the communications channel, consisting primarily of air, during a 6.67 mS period of time, such that the TDMA Frame 100 is 40 mS in duration.", "In accordance with current TDMA conventions, a TDMA Channel is made up of every third slot within the TDMA Frame.", "Thus, Slots 1 and 4 (102, 108) are a part of one TDMA channel, Slots 2 and 5 (104, 110) part of another TDMA channel, and Slots 3 and 6 (106, 112) yet another.", "Within each TDMA channel, groups of 32 TDMA blocks (and thus 32 slots) comprise a Superframe 114, having a duration of 640 mS.", "A total of three Superframes, one per TDMA channel, are transmitted every 640 mS.", "Within each Superframe 114, a portion of the slots are designated the Broadcast Channel (BCCH), another portion Reserved, and another portion point-to-point messaging channel.", "Each mobile unit monitoring a particular base station is assigned to monitor a particular PCH Subchannel, i.e., a particular slot within the point-to-point messaging channel.", "As an example, slot 24 (116) may be the monitored PCH Subchannel for a particular group of mobile units within a cell (assuming for a given case slot 24 is part of the point-to-point messaging channel).", "The PCH Subchannel may contain any of a plurality of point-to-point communications encoded in 324 bits, which make up the PCH Subchannel.", "Referring next to FIG. 5, a block diagram is shown of an example of PCH Continuation in a digital control channel of the prior art.", "In the example shown, PCH Continuation activation occurs on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to Superframe Phase (SFP)=27, (i.e., slot 27).", "In the event the mobile station determines that there is no message addressed to its MSID in its PCH Subchannel, (i.e., slot 27), a PCON bit (i.e., page continuation bit) equals 1 and the base station has set a variable referred to as PCH -- DISPLACEMENT to 4, the mobile station proceeds to read every other point-to-point messaging slot starting with the point-to-point messaging slot corresponding to SFP=29 (i.e., slot 29) in the first primary Superframe.", "If slot 29 is read without receiving a message addressed to the mobile station, the mobile station continues to read every other point-to-point messaging slot with SFP=31, i.e., slot 31.", "If slots 29 and 31 are read without receiving a message addressed to the mobile station, the mobile station continues to read point-to-point messaging slots corresponding to SFP=n+1 and n+3, i.e., the second and fourth point-to-point messaging slots in the second primary Superframe.", "In the event these slots are read without receiving a message addressed to its MSID, at the point where an additional number of slots equal to the set PCH -- DISPLACEMENT have been read, the mobile station sleeps until the next occurrence of its assigned PCH Subchannel.", "Unfortunately, in accordance with the prior art system illustrated, in order to read all of the slots in which a page for the mobile station might appear, the mobile station either remains active during the entire secondary Superframe and the broadcast control channel of the second primary Superframe, or deactivates its receive channel during the secondary Superframe and broadcast control channel, keeping its processor awake.", "This amounts to more than 640 mS of additional actuation time during which the mobile station's processor, and possibly its receive channel, must remain active, i.e., turned on.", "Furthermore, and perhaps more importantly, this also represents a significant delay in reading the slots in which a page message might appear, and a significant inefficiency in the processing of page messages.", "Referring next to FIG. 6, a block diagram is shown of an example of point-to-point messaging channel message continuation in a digital control channel in accordance with the prior art.", "Point-to-point messaging channel message continuation activation is shown on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=27, i.e., slot 27.", "In the example shown, when the mobile station determines that there is no message addressed to its MSID in its assigned PCH Subchannel, and when the PCON bit is set to 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read every other point-to-point messaging channel slot starting with the slot corresponding to SFP=29, i.e., slot 29.", "In the present example, the radio unit receives, in slot 29, the first slot of a three point-to-point messaging slot page message addressed to its MSID.", "The mobile station next reads the point-to-point messaging slots corresponding to SFP=31 (i.e., slot 31) and SFP=n+1 (i.e., slot 5 in the next primary Superframe), which contains the remainder of the page message.", "Note that in accordance with another example, the mobile station determines that there is a message addressed to its MSID in its assigned PCH Subchannel, and the base station has set PCH -- DISPLACEMENT to 4.", "In this other example, the radio unit receives, in slot 27, the first slot of a four point-to-point messaging slot page message addressed to its MSID.", "The mobile station proceeds to read every other point-to-point messaging channel slot starting with the slot corresponding to SFP=29 and ending with the slot corresponding to SFP=n+1, as described in the preceding example.", "In accordance with this other example, the PCON bit is irrelevant.", "Point-to-point messaging channel message continuation may also be used when a non-page message requiring more than one point-to-point messaging slot (i.e., a multi-slot non-page message) is sent.", "In this case, the PCON bit is not a factor, i.e., is irrelevant, and the number of additional slots read will be a function of the type of multi-slot point-to-point message being sent, as opposed to a function of PCH -- DISPLACEMENT.", "Advantageously, the present embodiment thus effectively increases the bandwidth available for non-page messages, essentially without sacrificing the bandwidth available for page messages or hard pages (because, in accordance with, e.g., IS-136, multiple pages can be transmitted in a single slot using hard pages instead of page messages, which generally only carry a single page per slot).", "As an example, if there are 25 point-to-point messaging slots in a digital control channel, and all 25 are PCH Subchannel slots, when 25 mobile stations are to be paged, all 25 point-to-point messaging slots may be used for transmitting page messages, leaving no slots for non-page messages.", "If, however, four of the 25 slots are designated as Non-PCH Subchannel slots, in accordance with an example of the present embodiment, then the 25 mobile stations are paged in the 21 available PCH Subchannel slots--with some of the PCH Subchannel slots containing hard pages for paging up to three mobile stations in a single slot.", "In this way, the four Non-PCH Subchannel slots are left for carrying non-page messages (or for PCH Continuation or point-to-point messaging channel message continuation, as described herein below).", "Unfortunately, in accordance with the prior art system illustrated, in order to read all of the slots of the continued message, the mobile station may be required to maintain its receive channel in an active state and will be required to maintain its processor in an active state, not only during the slots to be read, but also during the entire secondary Superframe and the broadcast control channel of the second primary Superframe.", "This amounts to more than 640 mS of additional activation time during which the mobile station's processor and possibly receive channel, must remain active and, in addition, more than 640 ms of delay in receiving the continued message.", "Thus, as can be seen in FIGS. 5 and 6, significant additional activation time for the mobile station's processor, and possibly receive channel, and a significant delay in receiving point-to-point messages results when PCH Continuation or point-to-point messaging channel message continuation activation occurs on a full-rate digital control channel.", "Such increased activation and delay, however, tends to have a greater impact on those mobile stations that happen to be assigned to a PCH Subchannel that is at or near the end of the primary Superframe.", "Those mobile stations assigned to a PCH Subchannel earlier in the primary Superframe, e.g., corresponding to, e.g., SFP=11 (i.e., slot 11) generally will not be required to maintain their receive channels and/or processors in an active state during the secondary Superframe, because there will generally be a sufficient number of PCH Subchannels available following the assigned PCH Subchannel to fulfill the needs of PCH Continuation (FIG.", "5) or point-to-point messaging channel message continuation (FIG.", "6) activation.", "Problematically, mobile stations are not randomly assigned to their PCH Subchannel, but rather the PCH Subchannel is assigned based on a hash involving the mobile station identification number (MIN), and the available number of PCH Subchannels in the point-to-point messaging channel.", "Therefore, because the mobile station identification number and the number of slots in the point-to-point messaging channel of a particular base station are not likely to change very often, the mobile stations hashed to PCH Subchannels late (i.e., near the end, or to the right as oriented in FIGS. 5 and 6) in the primary Superframe are, over time, likely to be required to maintain their receive channels and/or processors in an active state for longer periods of time than those mobile stations having been assigned a PCH Subchannel earlier in the primary Superframe and are likely to experience greater delays in receiving pages and point-to-point messages.", "As a result, the mobile stations with PCH Subchannels late in the primary Superframe will tend to experience a higher power usage, and therefore a reduced battery life (due to the increased activation of their receive channels), and slower performance as compared with those mobile stations having a PCH Subchannel earlier in the primary Superframe.", "As a result, some subscribers to the cellular telephone system will, by virtue of their assigned mobile station identification numbers, receive inferior power consumption/battery life characteristics, and performance characteristics from their mobile stations.", "The present embodiment provides for a Non-PCH Subchannel slot information element in the broadcast control channel of each Superframe.", "The Non-PCH Subchannel slot information element uses two bits to specify the number of Non-PCH Subchannel slots within the point-to-point messaging channel.", "By way of example, in a full rate digital control channel, if the Non-PCH Subchannel slot information element is set to 00, all point-to-point messaging slots are eligible to be allocated as PCH Subchannels.", "If the Non-PCH Subchannel slot information element is set to 01, the last two point-to-point messaging slots cannot be allocated as PCH Subchannels, if the Non-PCH Subchannel slot information element is set to 10, the last four cannot be allocated as PCH Subchannels, and if the Non-PCH Subchannel slot information element is set to 11, the last six cannot be allocated as PCH Subchannels.", "In a half-rate digital control channel, the above Non-PCH Subchannel slot information element setting signify a reservation of zero slots, the last slot, the last two slots and the last three slots in the point-to-point messaging channel, respectively.", "Once slots are reserved through the Non-PCH Subchannel slot information element, they cannot be allocated as PCH Subchannels, i.e., they cannot be hashed to by mobile stations and by the base station when determining the appropriate PCH Subchannel to monitor for pages, or in which to transmit a page for a particular mobile station, respectively.", "They can, however, be used as additional slots for point-to-point messaging channel message continuation or PCH Continuation or for other non-page message traffic, such as access response and short message service (SMS) messages.", "Thus, when paging traffic increases within the point-to-point messaging channel, e.g., nearing 100% of UPR maximum paging capacity, or more, the number of slots designated in the Non-PCH Subchannel slot information element are, unlike in prior art systems, still available for the transmission of non-page messages.", "For example, as illustrated below in FIGS. 7 and 8, these Non-PCH Subchannel slots are available for point-to-point messaging channel message continuation and PCH Continuation, as well as for other non-page message traffic.", "Referring next to FIG. 7, a block diagram is shown illustrating an example of PCH Continuation in a digital control channel wherein an embodiment of the present invention is utilized to minimize the amount of activation of a mobile station's receive channel needed.", "PCH Continuation activation is illustrated as occurring on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=21 (i.e., slot 21).", "In the event the mobile station determines that there is no message addressed to its mobile station identification number in its PCH Subchannel (i.e., slot 27), when the PCON bit equals 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read point-to-point messaging slots corresponding to SFP=23, 25, 27 and 29 (i.e., slots 23, 25, 27 and 29--a number of slots equal to PCH -- DISPLACEMENT) in the first primary Superframe.", "Note that in the illustrated example, slots 26 through 31 of the point-to-point messaging channel are reserved for non-page messages, and therefore are not hashed to by mobile stations when determining their PCH Subchannel.", "(Note that the phrase "reserved for non-page messages"", "does not mean that such slots cannot be used for page messages, but merely that such slots are not hashed to by any mobile station when determining PCH Subchannel assignments.", "Such slots in accordance with the present embodiment, therefore, can only be read in response to PCH Continuation, point-to-point messaging channel message continuation, or when scanning for non-page point-to-point messages.) As a result, when the mobile station looks beyond its PCH Subchannel (as occurs in PCH Continuation and point-to-point messaging channel message continuation, or when the mobile station is searching for non-page point-to-point messages) there are, in this example, six Non-PCH Subchannel slots available after the last assigned PCH Subchannel for PCH Continuation, point-to-point messaging channel message continuation Message Continuation or non-page point-to-point messages.", "One result of having these Non-PCH Subchannel slots is that mobile stations with PCH subchannels late in the primary Superframe's point-to-point messaging channel are much less likely to have to maintain their processors and receive channels and/or processors in an active state through the secondary Superframe and into the next primary Superframe in order to receive PCH displaced pages or continued point-to-point messaging channel messages.", "A further result of having these Non-PCH subchannel slots is that these mobile stations with PCH subchannels late in the primary Superframe's point-to-point messaging channel are much less likely to experience delays caused by these PCH Continuation, point-to-point messaging channel message continuation or other multi-slot point-to-point messages that require slots in a subsequent Superframe.", "Another result is that there are always a few slots available for other non-page messages, such as access response messages (e.g., registration acceptance) or SMS messages, even in environments where pages greatly exceed UPR maximum paging capacity.", "Thus, the increased power consumption and decreased battery life, delays in message reception and reduced non-page message throughput, heretofore experienced by these mobile stations, is significantly reduced or eliminated by the present embodiment.", "Referring next to FIG. 8, a block diagram is shown illustrating an example of point-to-point messaging channel message continuation in the digital control channel in accordance with another embodiment of the invention.", "Point-to-point messaging channel message continuation activation on a full-rate digital control channel for a mobile station having a PCH Subchannel corresponding to SFP=21, (i.e., slot 21) is shown.", "When the mobile station determines that there is no message addressed to its MSID in the assigned PCH Subchannel, and when the PCON bit is set to 1 and the base station has set PCH -- DISPLACEMENT to 4, the mobile station proceeds to read the point-to-point messaging slot corresponding to SFP=23, (i.e., slot 23) and receives in such slot the first slot of a three point-to-point messaging slot page message addressed to its MSID.", "The mobile station next reads the point-to-point messaging slots corresponding to SFP=31 (i.e., slot 31), SFP=25 (i.e., slot 25) and SFP=27 (i.e., slot 27) in the primary Superframe.", "As with the example described above in FIG. 7, it can be seen that in the present embodiment, mobile stations having assigned (i.e., hashed) to them a PCH Subchannel late in the group of subchannels within the point-to-point messaging channel are able to receive a three slot point-to-point messaging channel message that has been continued from its assigned PCH Subchannel.", "Unlike in heretofore known cellular telephone systems, as described above in FIG. 6, the present embodiment eliminates or substantially reduces the need for these mobile stations having assigned PCH Subchannels late in the point-to-point messaging channel to maintain their receive channels and/or processors in an active state during the secondary Superframe and into the next primary Superframe (as illustrated in FIG. 6);", "and substantially improves the performance of these mobile station by eliminating delays in the reception of non-page messages due to their spanning more than one Superframe.", "While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims." ]
BACKGROUND OF THE INVENTION [0001] This invention relates to an active piezoelectric spindle bearing preload adjustment mechanism and particularly a mechanism that is capable of generating electric power through rotation of the shaft in the a spindle to control the contracted deformation of a piezoelectric material for adjusting bearing preload alteration [0002] Increasing demands for machining precision on machine tools and great expansion of machining applications have created a lot of challenge to the fabrication of high-speed spindle. One of the manufacturing issues pending to be resolved is the generation of thermo power efficiency of the spindle. For instance, the thermo source originated from a driving motor and preload friction of the rotating elements such as bearing increases rapidly when rotation speed accelerated. Furthermore, high-speed rotation of the spindle generates centrifugal force which makes bearing components such as inner and outer rings and steel balls squeezing against each other and produces thermal stress which in turn increases bearing preload. The increased bearing preload further makes the rotating bearing generating even more thermo energy. This vicious cycle thus makes bearing internal thermo energy increasing at accelerating rate and may make bearing preload become exceedingly high. If increasing of bearing preload is done without proper control of thermal stress, the bearing would be eventually burned out and destroyed. Bearing service life and durability will be suffered. [0003] Hence how to reduce the increase of spindle bearing preload caused by thermal expansion is an important issue in the research and development of high-speed spindle technology. Many new technologies regard bearing preload adjustment have been announced and introduced over the years. In general, bearing preload method may be categorized in three types, i.e. fixed position preload, constant pressure preload and variable preload. [0004] In the fixed position preload technique, a fixed dimension element such as spacer ring is disposed between the bearing and a stationary block. The spacer ring presses the bearing to provide the bearing a selected preload for increasing the rigidity and supporting capacity of the spindle. When the spindle rotates at a relatively low speed, this type of preload technique may provide the spindle a desirable rigidity. However when the spindle rotates at high speed, temperature will increase and may result in thermal expansion and preload overshoot and causes bearing failure. [0005] In the constant pressure preload technique, the spindle is subjected to a constant axial pressure for providing the spindle a desirable preload. Using spring to render the preload to the spindle is a commonly used method for high-speed spindle at present. The spring can provide a constant preload. When bearing preload changes due to the factors such as rotation speed change or temperature increase, the spring may absorb the excess preload by its small displacement and almost does not increase preload value. However when using this method for preloading spindle bearing of machine for low speed and heavy duty machining work, the spring cannot provide the bearing sufficient load to increase the rigidity and supporting capacity of the spindle. Not enough rigidity will affect machining precision. Hence spring preload is only suitable for high-speed spindle. [0006] Variable preload technique is to overcome the disadvantage of rigidity inadequacy of the spring preload mechanism. One of the variable preload techniques is using clutch principle by adapting the constant position and constant pressure mechanism on the spindle bearing. When the spindle rotates at low speed, the clutch is actuated to switch to the fixed position preload mechanism for providing the bearing a higher rigidity and supporting capacity. When the spindle rotates at high speed, switch to the constant pressure preload mechanism for providing the bearing a lower preload to prevent spindle rigidity overshoot. This technique is simpler and easier to implement. However it needs more space. Moreover, precision control is difficult. Hence it is not commercially available at present. Another variable preload technique is hydraulic preload mechanism which is widely used now. FIG. 1 illustrates its main features. There is a hydraulic cylinder assembly 2 engaging with the spindle 1 externally. The piston rod 21 can move reciprocally to control the axial displacement of the outer ring 111 of the bearing 11 for controlling the bearing preload. This technique needs an additional hydraulic source and other peripheral equipment. It costs higher and also needs a lot of space. The design of the spindle 1 has to include many more factors. Furthermore, preload level of the hydraulic preload mechanism is easily affected by pressure pulse. Once hydraulic source is not effective, the preload value will change significantly and may result in damaging the spindle 11 . [0007] [0007]FIGS. 2 and 3 show another known technology. It is an externally powered piezoelectric type preload control mechanism which has a piezoelectric material 3 . When the piezoelectric material 3 subjects to an electric field, it will extend slightly along the electric field direction for controlling bearing preload. When the shaft 12 rotates at low speed, external power source provides a higher DC voltage for the piezoelectric material 3 to extend axially and push a preload adjustment block 4 for changing bearing 11 slide distance whereby providing sufficient bearing preload to maintain the rigidity of the shaft 12 . When shaft 12 rotation speed and temperature increase, the external powered voltage is gradually decreased to reduce the extension of the piezoelectric material 3 . In order to control bearing preload properly, bearing preload output value should be measured constantly by using a measuring device such as load cells made from strain gauge. Then a computer will be used to control the DC voltage and feedback to the piezoelectric material 3 for a close loop control process to adjust the bearing preload. This mechanism needs expensive external control devices and has a very complex structure. It becomes a roadblock to commercialization. SUMMARY OF THE INVENTION [0008] In view of aforesaid disadvantages, it is therefore an object of this invention to dispose a preload control assembly and an internal generator inside a spindle that are able to automatically adjust bearing preload according to spindle rotation speed without external control systems to measure and adjust preload output value whereby to increase reliability at a lower cost. [0009] Another object of this invention is to enable the spindle to generate electric power during rotation so that the mechanism may function without external power supply and may reduce the costs of peripheral devices. It is also more environment friendly. [0010] Still another object of this invention is to dispose the mechanism inside the spindle so that no additional space is needed. [0011] In order to achieve aforesaid objects, this invention provides a preload adjustment assembly between the inner ring and outer ring of two bearings and has an internal generator disposed at a selected location in the spindle. The preload adjustment assembly includes a spacer ring set and a piezoelectric actuator located in the spacer ring set. When the spindle rotates, the internal generator produces electric power resulting from the spindle rotation and provides a voltage for controlling piezoelectric actuator extension length whereby to change slide distance of the inner and outer ring for controlling the preload value. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The invention, as well as its many advantages, may be further understood by the following detailed description and drawings, in which: [0013] [0013]FIG. 1 is a fragmentary schematic sectional view of a conventional hydraulic preload control mechanism. [0014] [0014]FIG. 2 is a fragmentary schematic sectional view of a conventional piezoelectric type preload control mechanism.. [0015] [0015]FIG. 3 is an enlarged fragmentary sectional view according to FIG. 2. [0016] [0016]FIG. 4 is a schematic view showing the relationship of electric field and strain of piezoelectric material. [0017] [0017]FIG. 5 is a schematic sectional view of this invention. [0018] [0018]FIG. 6 is an enlarged fragmentary sectional view of this invention according to FIG. 5. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] Referring to FIG. 4, applying an electric field to a piezoelectric material 3 usually will cause the piezoelectric material 3 to produce a small displacement. Their relationship may be calculated by the following equation: d=ε/E [0020] where: d is piezoelectric constant, ε is strain value, E is electric field applied to the piezoelectric material 3 [0021] Based on above equation, a greater value of d means that strain has a higher sensitivity in the electric field. In the general applications of piezoelectric material 3 , most considerations are focusing on extension deformation application along the electric field direction, and neglect the contraction of the piezoelectric material 3 in the direction normal to the electric field. [0022] Referring to FIG. 4, in the coordinates composed of XYZ axes, when an electric field is applied to a piezoelectric material 3 at the Z-axis direction, the piezoelectric material 3 will produce an extension in the electric field direction (i.e. Z-axis direction), and will have contraction in the X and Y-axes directions (shown by phantom lines). This invention uses the contraction deformation characteristics of the piezoelectric material 3 to control bearing preload. [0023] Referring to FIG. 5, this invention includes two main portions. The first portion includes a preload adjustment assembly 6 located between a bearing outer ring 111 and a bearing inner ring 112 of two sets of bearing 11 which are mounted on a spindle 1 in a back-to-back assembly fashion. The preload adjustment assembly 6 includes a spacer ring set 7 and a piezoelectric actuator 8 located in the spacer ring set 7 . The piezoelectric actuator 8 includes a plurality of thin-flake-shaped piezoelectric material 3 stacked one upon the other. The spacer ring 7 includes a first spacer ring 71 and a second spacer ring 72 which have a selected gap formed therebetween. The first spacer ring 71 includes a first ring 711 and a second ring 712 . The second ring 712 has an extended flange at the bottom thereof to form a compartment with the first ring 711 for holding the piezoelectric actuator 8 therein. The first and second ring 711 and 712 and the piezoelectric actuator 8 sandwiched therebetween have a longer axial length than the back-to-back assembly interval between the two outer rings 111 , whereby provides an axial thrust force to press the spacer ring set 7 between the back-to-back assembly of the bearing 11 . The piezoelectric actuator 8 has a smaller compartment space in radial direction of the bearing 11 than the compartment radial space between the first and second ring 711 and 712 . Hence there is a selected radial gap when the piezoelectric actuator 8 is held between the first and second ring 711 and 712 . [0024] The second portion includes a rotary shaft 12 located in the spindle 1 and an internal generator 9 disposed at a selected location in a stationary spindle front block 13 . The generator 9 includes a coil 91 and a permanent magnet 92 and is wired to a semiconductor rectifier 93 . The permanent magnet 92 is located on the shell of the shaft 12 . The coil 91 is located in the spindle front block 13 mating against the permanent magnet 92 . The semiconductor rectifier 93 has one end electrically connecting with the coil 91 and another end electrically connecting with the piezoelectric actuator 8 , whereby the coil 91 , semiconductor rectifier 93 and piezoelectric actuator 8 form a loop. When the permanent magnet 92 rotates along with the shaft 12 , the coil 91 forms a rotational magnetic field and result in change of magnetic flux in the coil 91 , consequently generate induction current and voltage in the coil 91 . The variation of current is rectified through the semiconductor rectifier 8 to become DC current and input to the piezoelectric actuator 8 , and generates an electric field in the piezoelectric actuator 8 along the radial direction of the bearing 11 , whereby the piezoelectric actuator 8 produces an extension along the bearing 11 radial direction and a contraction along the bearing 11 axial direction. When the shaft 12 rotation speed increases, output voltage from the coil 91 will also increase. In the mean time, the electric field intensity along the bearing 11 radial direction also increases. [0025] By means of aforesaid structure, the spacer ring set 7 is compressed at the bearing 11 axial direction between the back-to-back assembly of the bearing 11 , and may provide the shaft 12 an initial bearing preload when the shaft 12 starts rotation at a low speed (such as for heavy duty machining at low speed) so that the shaft 12 will have greater rigidity and supporting capacity. After adjusting the parameters for the piezoelectric actuator 8 and internal generator 9 , if the spindle bearing 11 rotation speed increases and the bearing preload becomes too high (such as at high-speed machining operation), the internal generator 9 , because of higher rotation speed of the shaft 12 , will generate greater electric field intensity in the piezoelectric actuator along the bearing 11 radial direction, and result in a selected contraction of the piezoelectric actuator 8 in the bearing axial direction. When the piezoelectric actuator 8 is contracted axially, the axial thrust force of the first spacer ring 71 against the bearing outer ring 111 will be decreased. Consequently bearing 11 preload will become lower and may result lower rigidity for the shaft 12 so that the machine tool may maintain desirable machining precision when the shaft 12 rotates at high speed. Furthermore, when the shaft 12 rotates at high speed, the piezoelectric actuator 8 has an extension in bearing 11 radial direction. Before the piezoelectric actuator 8 extends, it has a smaller space in the bearing 11 radial direction than the compartment space formed between the first and second ring 711 and 712 . This extra space between the ring 711 and 712 will be available for the piezoelectric actuator 8 extending use. Hence the piezoelectric actuator 8 won't compress the first and second spacer ring 71 and 72 in the bearing radial direction and may prevent the spacer ring set 7 from damage. When the shaft 12 rotation speed decreases, voltage provided by the internal generator 9 also decreases. The piezoelectric actuator 8 will gradually restore to its initial form and provide the bearing 11 a higher preload value for giving the shaft 12 required rigidity at low speed. [0026] It may thus be seen that the objects of the present invention set forth herein, as well as those made apparent from the foregoing description, are efficiently attained. While the preferred embodiment of the invention has been set forth for purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.
An active piezoelectric spindle bearing preload adjustment mechanism includes a preload adjustment assembly located between an inner ring and an outer ring of two bearings, and an internal generator mounted at a selected location in a spindle. The preload adjustment assembly includes a spacer ring set and a piezoelectric actuator located in the spacer ring set. The rotation speed of the spindle is changeable to enable the internal generator generating selected amount of power and voltage for controlling extension or contraction length of the piezoelectric actuator whereby to change slide distance between the inner and outer ring for controlling bearing preload value.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "BACKGROUND OF THE INVENTION [0001] This invention relates to an active piezoelectric spindle bearing preload adjustment mechanism and particularly a mechanism that is capable of generating electric power through rotation of the shaft in the a spindle to control the contracted deformation of a piezoelectric material for adjusting bearing preload alteration [0002] Increasing demands for machining precision on machine tools and great expansion of machining applications have created a lot of challenge to the fabrication of high-speed spindle.", "One of the manufacturing issues pending to be resolved is the generation of thermo power efficiency of the spindle.", "For instance, the thermo source originated from a driving motor and preload friction of the rotating elements such as bearing increases rapidly when rotation speed accelerated.", "Furthermore, high-speed rotation of the spindle generates centrifugal force which makes bearing components such as inner and outer rings and steel balls squeezing against each other and produces thermal stress which in turn increases bearing preload.", "The increased bearing preload further makes the rotating bearing generating even more thermo energy.", "This vicious cycle thus makes bearing internal thermo energy increasing at accelerating rate and may make bearing preload become exceedingly high.", "If increasing of bearing preload is done without proper control of thermal stress, the bearing would be eventually burned out and destroyed.", "Bearing service life and durability will be suffered.", "[0003] Hence how to reduce the increase of spindle bearing preload caused by thermal expansion is an important issue in the research and development of high-speed spindle technology.", "Many new technologies regard bearing preload adjustment have been announced and introduced over the years.", "In general, bearing preload method may be categorized in three types, i.e. fixed position preload, constant pressure preload and variable preload.", "[0004] In the fixed position preload technique, a fixed dimension element such as spacer ring is disposed between the bearing and a stationary block.", "The spacer ring presses the bearing to provide the bearing a selected preload for increasing the rigidity and supporting capacity of the spindle.", "When the spindle rotates at a relatively low speed, this type of preload technique may provide the spindle a desirable rigidity.", "However when the spindle rotates at high speed, temperature will increase and may result in thermal expansion and preload overshoot and causes bearing failure.", "[0005] In the constant pressure preload technique, the spindle is subjected to a constant axial pressure for providing the spindle a desirable preload.", "Using spring to render the preload to the spindle is a commonly used method for high-speed spindle at present.", "The spring can provide a constant preload.", "When bearing preload changes due to the factors such as rotation speed change or temperature increase, the spring may absorb the excess preload by its small displacement and almost does not increase preload value.", "However when using this method for preloading spindle bearing of machine for low speed and heavy duty machining work, the spring cannot provide the bearing sufficient load to increase the rigidity and supporting capacity of the spindle.", "Not enough rigidity will affect machining precision.", "Hence spring preload is only suitable for high-speed spindle.", "[0006] Variable preload technique is to overcome the disadvantage of rigidity inadequacy of the spring preload mechanism.", "One of the variable preload techniques is using clutch principle by adapting the constant position and constant pressure mechanism on the spindle bearing.", "When the spindle rotates at low speed, the clutch is actuated to switch to the fixed position preload mechanism for providing the bearing a higher rigidity and supporting capacity.", "When the spindle rotates at high speed, switch to the constant pressure preload mechanism for providing the bearing a lower preload to prevent spindle rigidity overshoot.", "This technique is simpler and easier to implement.", "However it needs more space.", "Moreover, precision control is difficult.", "Hence it is not commercially available at present.", "Another variable preload technique is hydraulic preload mechanism which is widely used now.", "FIG. 1 illustrates its main features.", "There is a hydraulic cylinder assembly 2 engaging with the spindle 1 externally.", "The piston rod 21 can move reciprocally to control the axial displacement of the outer ring 111 of the bearing 11 for controlling the bearing preload.", "This technique needs an additional hydraulic source and other peripheral equipment.", "It costs higher and also needs a lot of space.", "The design of the spindle 1 has to include many more factors.", "Furthermore, preload level of the hydraulic preload mechanism is easily affected by pressure pulse.", "Once hydraulic source is not effective, the preload value will change significantly and may result in damaging the spindle 11 .", "[0007] [0007 ]FIGS. 2 and 3 show another known technology.", "It is an externally powered piezoelectric type preload control mechanism which has a piezoelectric material 3 .", "When the piezoelectric material 3 subjects to an electric field, it will extend slightly along the electric field direction for controlling bearing preload.", "When the shaft 12 rotates at low speed, external power source provides a higher DC voltage for the piezoelectric material 3 to extend axially and push a preload adjustment block 4 for changing bearing 11 slide distance whereby providing sufficient bearing preload to maintain the rigidity of the shaft 12 .", "When shaft 12 rotation speed and temperature increase, the external powered voltage is gradually decreased to reduce the extension of the piezoelectric material 3 .", "In order to control bearing preload properly, bearing preload output value should be measured constantly by using a measuring device such as load cells made from strain gauge.", "Then a computer will be used to control the DC voltage and feedback to the piezoelectric material 3 for a close loop control process to adjust the bearing preload.", "This mechanism needs expensive external control devices and has a very complex structure.", "It becomes a roadblock to commercialization.", "SUMMARY OF THE INVENTION [0008] In view of aforesaid disadvantages, it is therefore an object of this invention to dispose a preload control assembly and an internal generator inside a spindle that are able to automatically adjust bearing preload according to spindle rotation speed without external control systems to measure and adjust preload output value whereby to increase reliability at a lower cost.", "[0009] Another object of this invention is to enable the spindle to generate electric power during rotation so that the mechanism may function without external power supply and may reduce the costs of peripheral devices.", "It is also more environment friendly.", "[0010] Still another object of this invention is to dispose the mechanism inside the spindle so that no additional space is needed.", "[0011] In order to achieve aforesaid objects, this invention provides a preload adjustment assembly between the inner ring and outer ring of two bearings and has an internal generator disposed at a selected location in the spindle.", "The preload adjustment assembly includes a spacer ring set and a piezoelectric actuator located in the spacer ring set.", "When the spindle rotates, the internal generator produces electric power resulting from the spindle rotation and provides a voltage for controlling piezoelectric actuator extension length whereby to change slide distance of the inner and outer ring for controlling the preload value.", "BRIEF DESCRIPTION OF THE DRAWINGS [0012] The invention, as well as its many advantages, may be further understood by the following detailed description and drawings, in which: [0013] [0013 ]FIG. 1 is a fragmentary schematic sectional view of a conventional hydraulic preload control mechanism.", "[0014] [0014 ]FIG. 2 is a fragmentary schematic sectional view of a conventional piezoelectric type preload control mechanism..", "[0015] [0015 ]FIG. 3 is an enlarged fragmentary sectional view according to FIG. 2. [0016] [0016 ]FIG. 4 is a schematic view showing the relationship of electric field and strain of piezoelectric material.", "[0017] [0017 ]FIG. 5 is a schematic sectional view of this invention.", "[0018] [0018 ]FIG. 6 is an enlarged fragmentary sectional view of this invention according to FIG. 5. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0019] Referring to FIG. 4, applying an electric field to a piezoelectric material 3 usually will cause the piezoelectric material 3 to produce a small displacement.", "Their relationship may be calculated by the following equation: d=ε/E [0020] where: d is piezoelectric constant, ε is strain value, E is electric field applied to the piezoelectric material 3 [0021] Based on above equation, a greater value of d means that strain has a higher sensitivity in the electric field.", "In the general applications of piezoelectric material 3 , most considerations are focusing on extension deformation application along the electric field direction, and neglect the contraction of the piezoelectric material 3 in the direction normal to the electric field.", "[0022] Referring to FIG. 4, in the coordinates composed of XYZ axes, when an electric field is applied to a piezoelectric material 3 at the Z-axis direction, the piezoelectric material 3 will produce an extension in the electric field direction (i.e. Z-axis direction), and will have contraction in the X and Y-axes directions (shown by phantom lines).", "This invention uses the contraction deformation characteristics of the piezoelectric material 3 to control bearing preload.", "[0023] Referring to FIG. 5, this invention includes two main portions.", "The first portion includes a preload adjustment assembly 6 located between a bearing outer ring 111 and a bearing inner ring 112 of two sets of bearing 11 which are mounted on a spindle 1 in a back-to-back assembly fashion.", "The preload adjustment assembly 6 includes a spacer ring set 7 and a piezoelectric actuator 8 located in the spacer ring set 7 .", "The piezoelectric actuator 8 includes a plurality of thin-flake-shaped piezoelectric material 3 stacked one upon the other.", "The spacer ring 7 includes a first spacer ring 71 and a second spacer ring 72 which have a selected gap formed therebetween.", "The first spacer ring 71 includes a first ring 711 and a second ring 712 .", "The second ring 712 has an extended flange at the bottom thereof to form a compartment with the first ring 711 for holding the piezoelectric actuator 8 therein.", "The first and second ring 711 and 712 and the piezoelectric actuator 8 sandwiched therebetween have a longer axial length than the back-to-back assembly interval between the two outer rings 111 , whereby provides an axial thrust force to press the spacer ring set 7 between the back-to-back assembly of the bearing 11 .", "The piezoelectric actuator 8 has a smaller compartment space in radial direction of the bearing 11 than the compartment radial space between the first and second ring 711 and 712 .", "Hence there is a selected radial gap when the piezoelectric actuator 8 is held between the first and second ring 711 and 712 .", "[0024] The second portion includes a rotary shaft 12 located in the spindle 1 and an internal generator 9 disposed at a selected location in a stationary spindle front block 13 .", "The generator 9 includes a coil 91 and a permanent magnet 92 and is wired to a semiconductor rectifier 93 .", "The permanent magnet 92 is located on the shell of the shaft 12 .", "The coil 91 is located in the spindle front block 13 mating against the permanent magnet 92 .", "The semiconductor rectifier 93 has one end electrically connecting with the coil 91 and another end electrically connecting with the piezoelectric actuator 8 , whereby the coil 91 , semiconductor rectifier 93 and piezoelectric actuator 8 form a loop.", "When the permanent magnet 92 rotates along with the shaft 12 , the coil 91 forms a rotational magnetic field and result in change of magnetic flux in the coil 91 , consequently generate induction current and voltage in the coil 91 .", "The variation of current is rectified through the semiconductor rectifier 8 to become DC current and input to the piezoelectric actuator 8 , and generates an electric field in the piezoelectric actuator 8 along the radial direction of the bearing 11 , whereby the piezoelectric actuator 8 produces an extension along the bearing 11 radial direction and a contraction along the bearing 11 axial direction.", "When the shaft 12 rotation speed increases, output voltage from the coil 91 will also increase.", "In the mean time, the electric field intensity along the bearing 11 radial direction also increases.", "[0025] By means of aforesaid structure, the spacer ring set 7 is compressed at the bearing 11 axial direction between the back-to-back assembly of the bearing 11 , and may provide the shaft 12 an initial bearing preload when the shaft 12 starts rotation at a low speed (such as for heavy duty machining at low speed) so that the shaft 12 will have greater rigidity and supporting capacity.", "After adjusting the parameters for the piezoelectric actuator 8 and internal generator 9 , if the spindle bearing 11 rotation speed increases and the bearing preload becomes too high (such as at high-speed machining operation), the internal generator 9 , because of higher rotation speed of the shaft 12 , will generate greater electric field intensity in the piezoelectric actuator along the bearing 11 radial direction, and result in a selected contraction of the piezoelectric actuator 8 in the bearing axial direction.", "When the piezoelectric actuator 8 is contracted axially, the axial thrust force of the first spacer ring 71 against the bearing outer ring 111 will be decreased.", "Consequently bearing 11 preload will become lower and may result lower rigidity for the shaft 12 so that the machine tool may maintain desirable machining precision when the shaft 12 rotates at high speed.", "Furthermore, when the shaft 12 rotates at high speed, the piezoelectric actuator 8 has an extension in bearing 11 radial direction.", "Before the piezoelectric actuator 8 extends, it has a smaller space in the bearing 11 radial direction than the compartment space formed between the first and second ring 711 and 712 .", "This extra space between the ring 711 and 712 will be available for the piezoelectric actuator 8 extending use.", "Hence the piezoelectric actuator 8 won't compress the first and second spacer ring 71 and 72 in the bearing radial direction and may prevent the spacer ring set 7 from damage.", "When the shaft 12 rotation speed decreases, voltage provided by the internal generator 9 also decreases.", "The piezoelectric actuator 8 will gradually restore to its initial form and provide the bearing 11 a higher preload value for giving the shaft 12 required rigidity at low speed.", "[0026] It may thus be seen that the objects of the present invention set forth herein, as well as those made apparent from the foregoing description, are efficiently attained.", "While the preferred embodiment of the invention has been set forth for purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art.", "Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention." ]
RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/581,914 filed Jun. 22, 2004, and U.S. Provisional Patent Application Ser. No. 60/616/085 filed Oct. 5, 2004, both hereby incorporated by reference. STATEMENT REGARDING FEDERAL RIGHTS This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention. FIELD OF THE INVENTION The present invention relates generally to hydrogen evolution and storage and more particularly to a method and system for storing and evolving hydrogen. BACKGROUND OF THE INVENTION Hydrogen (H 2 ) is currently the leading candidate for a fuel to replace gasoline/diesel fuel in powering the nation's transportation fleet. There are a number of difficulties and technological barriers associated with hydrogen that must be solved in order to realize this “hydrogen economy”. Inadequate storage systems for on-board transportation hydrogen are recognized as a major technological barrier (see, for example, “The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs,” National Academy of Engineering (NAE), Board on Energy and Environmental Systems, National Academy Press (2004). One of the general schemes for storing hydrogen relates to using a chemical compound or system that undergoes a chemical reaction to evolve hydrogen as a reaction product. In principle, this chemical storage system is attractive, but all practical systems that have been studied to date involve either: (a) hydrolysis of high-energy inorganic compounds where the evolution of hydrogen is very exothermic (sodium borohydride/water as in the Millennium Cell's HYDROGEN ON DEMAND®, and lithium hydride as in SAFE HYDROGEN®, for example), thus making the cost of preparing the inorganic compound(s) high and life-cycle efficiency low; or (b) dehydrogenation of inorganic hydride materials (such as Na 3 AlH 6 /NaAlH 4 , for example) that release hydrogen when warmed but that typically have inadequate mass storage capacity and inadequate refueling rates. Inorganic compounds referred to in (a), above, produce hydrogen according to the chemical reaction MH x +XH 2 O→M(OH) x +XH 2   (1) where MH x is a metal hydride, and M(OH) x is a metal hydroxide. This reaction is irreversible. Inorganic hydride materials referred to in (b), above, produce hydrogen according to following chemical reaction, which is reversible with H 2 (hydrogen gas): MH x =M+ x /2H 2   (2) where MH x is a metal hydride, M is metal and H 2 is hydrogen gas. By contrast to the first reaction, which is irreversible with H 2 , the second reaction is reversible with H 2 . A practical chemical system that evolves hydrogen yet does not suffer the aforementioned inadequacies would be important to the planned transportation sector of the hydrogen economy. This same practical chemical system would also be extremely valuable for non-transportation H 2 fuel cell systems, such as those employed in laptop computers and other portable electronic devices, and in small mechanical devices such as lawnmowers where current technology causes significant pollution concerns. Any heat that must be input to evolve the hydrogen represents an energy loss at the point of use, and any heat that is evolved along with the hydrogen represents an energy loss where the chemical storage medium is regenerated. Either way, energy is lost, which diminishes the life-cycle efficiency. For most organic compounds, such as in those shown in equations 3-5 below, hydrogen evolution reactions are very endothermic, and the compounds are incompetent to evolve hydrogen at ambient temperature (i.e. thermodynamically incapable of evolving H 2 at significant pressure at ambient temperature). For temperatures less than about 250-400 degrees Celsius, the equilibrium pressure of hydrogen over most organic compounds is very small. As a consequence, most common organic compounds require heating above about 250 degrees Celsius, and the continual input of high-grade heat to maintain this temperature, in order to evolve hydrogen at a useful pressure. CH 4 → C + 2 H 2 ΔH 0 = +18 kcal/mol (3) ΔG 0 = +12 kcal/mol 6 CH 4 → cyclohexane + 6 H 2 ΔH 0 = +69 kcal/mol (4) ΔG 0 = +78 kcal/mol cyclohexane → benzene + 3 H 2 ΔH 0 = +49 kcal/mol (5) ΔG 0 = +23 kcal/mol Most organic compounds have hydrogen evolution reactions that are endergonic (i.e. having a net positive free energy of reaction change, i.e. ΔG>0) and their ambient temperature equilibrium hydrogen pressure is very low, practically unobservable. Thus, most organic compounds are unsuitable for hydrogen storage, based on both life-cycle energy efficiency and delivery pressure considerations. Decalin, for example, evolves hydrogen to form naphthalene when heated to about 250 degrees Celsius in the presence of a catalyst (see, for example, “Catalytic Decalin Dehydrogenation/Naphthalene Hydrogenation Pair as a Hydrogen Source for Fuel-Cell Vehicle,” S. Hodoshima, H. Arai, S. Takaiwa, and Y. Saito, Int. J. Hydrogen Energy (2003) vol. 28, pp.1255-1262, incorporated by reference herein). Hodoshima et al. use a superheated “thin film” reactor that operates at a temperature of at least 280 degrees Celsius to produce hydrogen from decalin at an adequate rate. Thus, this endothermic hydrogen evolution reaction requires both a complex apparatus and high-grade heat, which diminishes the life-cycle energy efficiency for hydrogen storage. Methods and systems that employ chemical compounds for storing and evolving hydrogen at ambient temperature with minimal heat input remain highly desirable. Therefore, an object of the present invention is a method for evolving hydrogen that is thermodynamically more favored than previously-described systems. Another object of the present invention is a thermodynamically favorable system for evolving hydrogen. Another object of the present invention is a reversible system for evolving and storing hydrogen. Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. SUMMARY OF THE INVENTION In accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention includes a method for producing hydrogen. The method involves exposing at least one chemical compound to a catalyst under conditions suitable for dehydrogenating the at least one chemical compound to form at least one product, the at least one chemical compound having the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure; and with the proviso that X and X′ cannot both be oxygen. The invention also includes a method for producing hydrogen, and involves exposing at least one chemical compound to a catalyst under conditions suitable for chemical reaction that forms hydrogen. The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; wherein R 8 and R 9 may be connected to each other to form a ring structure; and with the proviso that at least one of R 5 or R 11 is hydrogen. The invention also includes a method for producing hydrogen, comprising exposing at least one chemical compound and an acid to a catalyst under conditions suitable for chemical reaction that forms hydrogen. The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The acid may be an alcohol, a phenol, or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid can be water); and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine, quinoline, ammonia, and amine. The invention also includes a system for producing hydrogen. The system includes at least one organic compound, an acid, and a catalyst suitable for facilitating a chemical reaction between the at least one chemical compound and the acid in order to form hydrogen. The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The acid may be an alcohol, a phenol, or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid can be water); and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine, quinoline, ammonia, and amine. The invention also includes a system for producing hydrogen. The system includes at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a system for producing hydrogen. The system includes at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl; wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2; wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl, aryl; and wherein R 3 is selected from hydrogen, alkyl, aryl. The system also includes a catalyst suitable for facilitating the dehydrogenation of the chemical compound. The invention also includes a system for producing hydrogen. The system includes a chemical compound having the formula wherein each R is independently selected from hydrogen, alkyl, and aryl; and a catalyst suitable for facilitating the dehydrogenation of the chemical compound. The invention also includes a system for producing hydrogen comprising a chemical compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group; and a catalyst suitable for facilitating the dehydrogenation of the chemical compound. The invention also includes a system for producing hydrogen comprising a chemical compound having the formula wherein Q is N or (C(R)); wherein each R is independently selected from hydrogen, alkyl, aryl, and a higher fused ring group; and a catalyst suitable for facilitating the dehydrogenation of said chemical compound. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode. The hydrogen-generating fuel source includes at least one chemical compound and a catalyst suitable for dehydrogenating the chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure. The invention also includes a fuel cell comprising an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl; wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2; wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl and aryl; and wherein R 3 is selected from hydrogen, alkyl, aryl. The invention also includes a method for storing hydrogen. The method involves exposing at least one chemical compound to hydrogen in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has an anion and cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a method for storing hydrogen, which includes exposing at least one chemical compound to a reducing agent, the chemical compound having an anion and a cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a method for storing hydrogen, and involves exposing at least one chemical compound to hydrogen or to a reducing agent in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure; and with the proviso that X and X′ cannot both be oxygen. DETAILED DESCRIPTION The present invention relates to a chemical system useful for chemical hydrogen storage. Using the chemical system of the invention, hydrogen (H 2 ) is evolved without significant input or evolution of heat. One aspect of the present invention relates to hydrogen evolution from chemical compounds according to equation 6: wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure; and with the proviso that X and X′ cannot both be oxygen. For equation 6, it is believed that the ΔH 0 varies from about +10 kcal/mole to about −2 kcal/mole, and the ΔG 0 varies from about +5 kcal/mole to about −10 kcal/mole. Thus, the chemical reaction for hydrogen evolution as shown in Equation 6 above is nearly thermoneutral, perhaps even slightly exothermic, based on the currently available thermodynamic data for these materials. Owing to the favorable entropy of hydrogen evolution, the reaction can become exergonic (having a standard free energy change, ΔG 0 , of less than zero) and the ambient temperature equilibrium pressure of hydrogen approaches or exceeds the DOE target of 3 atmospheres. If the chemical compound is stabilized against classical functional group elimination by, for example, the presence of additional atoms that join to form a ring structure, then it is expected that the hydrogen evolution and hydrogenation will be reversible in the presence of a suitably active catalyst that selectively catalyzes the hydrogen evolution reaction and also the reverse reaction (i.e. the hydrogenation reaction). Such reversibility is advantageous because it allows the chemical compound to be regenerated simply by hydrogenation under pressure, and the energy cost of regenerating the chemical compound is likely to be minimal. Another aspect of the invention is related to a method and chemical system for producing hydrogen. This aspect of the invention involves exposing one or more chemical compounds to a catalyst under conditions suitable for a chemical reaction that forms hydrogen. Chemical compounds that evolve hydrogen according to the present invention include those having the chemical formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; wherein R 8 and R 9 may be connected to each other to form a ring structure; and with the proviso that at least one of R 5 or R 11 is hydrogen. When Q is —(C(R 7 R 8 )) n — where n is greater than one, and when Q is —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, the invention is meant to include structures where R 7 and R 8 in one C(R 7 R 8 ) grouping might be the same, but are not necessarily the same, as the R 7 and R 8 in another C(R 7 R 8 ) grouping. Structures such as the one shown below on the right, for example, where n is two and where R 7 and R 8 in one grouping are H and methyl, and are ethyl and phenyl in another grouping, are invention structures. An embodiment system including a chemical compound exemplary of the above formula was used to demonstrate this aspect of the present invention, and is shown in equation 7 below. While not intending to be bound by any particular explanation, it is believed that the compound shown on the top left of equation 7 tautomerizes to the zwitterionic form shown on the bottom left and that hydrogen evolution from either of these forms produces the species shown on the right. The hydrogen evolution reaction is a classically “symmetry forbidden” reaction. Therefore, the hydrogen evolution reaction is typically very slow in the absence of a suitable catalyst. Examples of catalysts that may facilitate hydrogen evolution include, for example, rhodium or ruthenium-based hydrogen transfer catalysts, ruthenium-based formic acid decomposition catalysts, nickel/copper/zinc-based reformation/hydrogenation catalysts, and the like. Catalysts useful with the present invention also include various forms of palladium, such as finely divided palladium metal, palladium supported on carbon, palladium supported on alumina, palladium supported on silica, a slurry of palladium in a solvent, a fluidized bed comprising palladium, a packed bed comprising palladium, or palladium carboxylate. For the system shown in equation 7, hydrogen evolution was observed in the presence of a palladium catalyst at a reaction temperature of from room temperature to about 60-70 degrees Celsius (a temperature range of from about 20 degrees Celsius to about 250 degrees Celsius will facilitate the reaction). Interestingly, in the absence of the catalyst, the compound shown top left does not evolve hydrogen after heating at 185 degrees Celsius for 8 days (see P. Brunet and J. D. Wuest “Formal Transfers of Hydride from Carbon-Hydrogen Bonds. Attempted Generation of H 2 by Intramolecular Protonolysis of the Activated Carbon-Hydrogen Bonds of Dihydrobenzimidazoles,” Can. J. Chem. (1996) vol. 74, p. 689). The system shown in equation 7 employs an acidic functional group. Other aspects of this invention relate to a method and system that relate to chemical compounds that may, but do not necessarily include acidic functional groups. Compounds of this type could be used with a catalyst and separate acid. This aspect of the invention relates to evolving hydrogen by exposing at least one chemical compound and an acid to a catalyst under conditions suitable for chemical reaction that forms hydrogen. Chemical compounds of this type have the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The acid can be an alcohol (methyl alcohol, ethyl alcohol, trifluoromethyl alcohol, and the like), a phenol (phenol, resorcinol, catechol, naphthol, and the like), or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid may be water); and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine quinoline, ammonia, and amine. Some examples of an acid HX useful with this invention include, but are not limited to, acetic acid, succinic acid, benzoic acid, and acrylic acid. Preferably, the compound and/or the acid HX or HTX is (are) chosen such that the change in the standard free energy of the chemical reaction comprises a standard free energy in the range of from about +5 kilocalories per mole to about −10 kilocalories per mole. The compound may be dissolved in a solvent chosen to stabilize the at least one organic compound and any cationic reaction products derived therefrom, so that the change in the standard free energy of the chemical reaction comprises a standard free energy in the range of from about +5 kilocalories per mole to about −10 kilocalories per mole. Examples of solvents useful with the present invention include polar organic and inorganic solvents such as, but not limited to, water, acetonitrile, tetrahydrofuran, pyridine, dimethylsulfoxide (DMSO), dimethylformamide (DMF), acetone, methyl ethyl ketone, methanol, ethanol, isopropanol, and the like. Ionic liquid solvents, also know in the art as “molten salts,” may also be used as solvents. Ionic liquids useful with this invention have been described, for example, in PCT Patent Application WO 01/93363 to A. McEwen et al. entitled “Non-Flammable Electrolytes”; in Japanese Patent 98168028 to M. Watanabe et al. entitled “Room Temperature Molten Salts and Electrochemical Devices Using the Salts”; in U.S. Pat. No. 6,365,301 to C. Michot et al. entitled “Materials Useful as Electrolytic Solutes,” which issued on Apr. 2, 2002; in “Room Temperature Ionic Liquids of Alkylimidazolium Cations and Fluoroanions” by R. Hagiwara and Y. Ito, J. Fluorine Chem. vol.105, (2000), pp. 221-227; in “Room-Temperature Molten Salts Based on the Quaternary Ammonium Ion” by J. Sun, M. Forsyth, and D. R. MacFarlane, J. Phys. Chem. B, 1998, vol.102, pages 8858-8864; and in U.S. Pat. No. 5,827,602 to V. R. Koch et al. entitled “Hydrophobic Ionic Liquids,” which issued Oct. 27, 1998, all incorporated by reference herein. Another aspect of this invention relates to a method and system for producing hydrogen that employs compounds having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl; wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2; wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl, aryl; and wherein R 3 is selected from hydrogen, alkyl, aryl. The system also includes a catalyst suitable for facilitating the dehydrogenation of the chemical compound. Another aspect of the present invention is related to hydrogen storage, and involves exposing at least one chemical compound to a hydrogen in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which includes anion and cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a method for storing hydrogen, which includes exposing at least one chemical compound to a reducing agent, the chemical compound having an anion and a cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and −N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The reducing agents may one or more of lithium borohydride, sodium borohydride, potassium borohydride, sodium hydride, potassium hydride, magnesium hydride, lithium hydride, calcium hydride, and electron plus proton where the electron can be provided by a metal reducing agent (zinc, for example). The invention also includes a method for storing hydrogen, and involves exposing at least one chemical compound to hydrogen or to a reducing agent in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure; and with the proviso that X and X′ cannot both be oxygen. Another example of a system for hydrogen evolution and storage is related to chemical compounds known generally as triazacyclohexanes, which are also known in the art as hexahydrotrazines. These materials evolve hydrogen and a product known more generally as a triazine. In this system, three molecules of hydrogen may be produced from one molecule of the triazacyclohexane. The amount of evolvable hydrogen for trazacyclohexane is 6.9 weight percent. The dehydrogenation reaction is slightly endothermic (ΔH=+17 kcal/mole by calculation) and exergonic (ΔG=−9 kcal/mole by calculation). Examples of these types of materials that can be used to produce a hydrogen evolving system of the invention include, for example, a compound having the formula wherein each R is independently selected from hydrogen, alkyl, and aryl; and a compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group; and a compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group. For these compounds, a catalyst is included for facilitating the dehydrogenation of the chemical compound. The method and system of the present invention can be used with a fuel cell to provide power to portable devices such as laptop or handheld computers, cellular phones, global positioning system receivers, CD/MP3 music players, flashlights, and the like, and vehicles. The following details relate to aspects of the invention that relate to fuel cells. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode. The hydrogen-generating fuel source includes at least one chemical compound and a catalyst suitable for dehydrogenating the chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—; wherein X′ is oxygen, —N(H)— or —N(R 4 )—; wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid; and wherein R 1 and R 3 can be connected to each other to form a ring structure. The invention also includes a fuel cell comprising an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )—; wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl. phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ). wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; wherein R 8 and R 9 may be connected to each other to form a ring structure; and with the proviso that at least one of R 5 or R 11 is hydrogen. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—; wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—; wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl; wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid; wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl; wherein R 7 and R 8 may be connected to each other to form a ring structure; and wherein R 8 and R 9 may be connected to each other to form a ring structure. The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl; wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2; wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl and aryl; and wherein R 3 is selected from hydrogen, alkyl, aryl. With a suitable catalyst, the hydrogen reaction becomes reversible, allowing the organic compounds to function as reversible hydrogen carriers that are capable of carrying hydrogen from one region of a device to another. The following EXAMPLES illustrate embodiments of the present invention. EXAMPLE 1 Catalytic dehydrogenation of A solution of compound 1 (9 mg, 0.03 mmol) in CD 3 CN (0.7 ml) was prepared in a nuclear magnetic resonance (NMR) tube. Palladium acetate (Pd(O 2 CCH 3 ) 2 , 1 mg, 0.003 mmol) was added to the tube. Upon mixing, a black precipitate formed and effervescence was observed. The reaction mixture was then heated to a temperature of about 70 degrees Celsius for about 30 minutes, resulting in a 90 percent conversion of (1) to which was confirmed by 1 H NMR spectroscopy. 1 H NMR (1) (THF-d 8 , 25° C., 400 MHz): δ 8.08 (d, 1H, aromatic), δ 7.83 (d, 1H, aromatic), δ 7.53 (t, 1H, aromatic), δ 6.56 (m, 2H, aromatic), δ 6.31 (m, 2H, aromatic), δ 6.00 (s, 1H, RN 2 CH), δ 2.50 (s, 6H, CH 3 ). 1 H NMR (2) (CD 3 CN, 25° C., 400 MHz): δ 8.23 (d, 1H, aromatic), δ 7.77 (m, 2H, aromatic), δ 7.72 (t, 1H, aromatic), δ 7.60 (m, 3H, aromatic), δ 7.40 (d, 1H, aromatic), δ 3.52 (s, 6H, CH 3 ). Evolution of molecular hydrogen from compound (1) was confirmed by catalytic hydrogenation of trans-stilbene with the hydrogen evolved from compound (1). In an experimental set-up, a flask was charged with compound (1) (50 mg, 0.18 mmol) and Pd(O 2 CCH 3 ) 2 (3 mg, 0.013 mmol) in acetonitrile. A separate flask was charged with trans-stilbene (34 mg, 0.18 mmol) and 10% Pd on carbon (20 mg) in benzene. The headspaces of the two flasks were immediately connected with a transfer tube. After about 12 hours, the contents of both flasks were analyzed using 1 H NMR spectroscopy. Complete conversion of compound (1) to compound (2) was observed for the first flask. Hydrogenation of the trans-stilbene in the second flask was 47% complete, confirming the evolution of hydrogen from compound (1). EXAMPLE 2 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that Pearlman's catalyst (Pd(OH) 2 /C) was used instead of palladium acetate. EXAMPLE 3 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that Pd/C was used instead of palladium acetate. EXAMPLE 4 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that PdCl 2 (bipyridine) was used instead of palladium acetate. EXAMPLE 5 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that K 2 PdCl 4 was used instead of palladium acetate. EXAMPLE 6 Catalytic dehydrogenation of in the presence of acid. A solution of compound (3) in CD 3 CN (0.7 ml) solvent was prepared in an NMR tube. Acetic acid (0.015 ml, 0.26 mmol) was added to the solution and the contents were mixed thoroughly. Palladium acetate (1 mg, 0.003 mmol) was then added to the mixture, after which a black precipitate formed and effervescence was observed. The NMR tube was heated to a temperature of about 70 degrees Celsius for about 30 minutes, resulting in complete conversion of compound 3 to (X═CH 3 COO − ), which was confirmed by 1 H NMR spectroscopy. 1 H NMR (3) (CD 3 CN, 25° C., 400 MHz): δ 7.56-7.45 (m, 5H, aromatic), δ 6.66-6.44 (m, 4H, aromatic), δ 4.84 (s, 1H, N 2 RCH), δ 2.50 (s, 6H, NCH 3 ). 1 H NMR (4) (HX=acetic acid, CD 3 CN, 25° C., 300 MHz): δ 8.0-7.6 (m, 9H, aromatic), δ 3.87 (s, 6H, CH 3 N), δ 1.80 (s, 3H, CH 3 CO 2 ). EXAMPLE 7 Catalytic dehydrogenation of in the presence of acid and a homogeneous catalyst. A solution of compound 5 (15 mg, 0.10 mmol), acetic acid (60 mg, 1.0 mmol) and CD 3 CN (0.70 ml) was prepared in an NMR tube. The solution was mixed, after which RhCl(PPh 3 ) 3 (0.3 mg, 0.37 μmol, Ph═C 6 H 5 ) was added to the solution. The mixture was heated at a temperature of about 70 degrees Celsius for about one hour, resulting in a 43% conversion of compound (5) to (X═CH 3 COO − ), which was confirmed by 1 H NMR spectroscopy. Turnover number (TON)=117 at 70° C. in 1 hour. 1 H NMR (5) (CD 3 CN, 25° C., 400 MHz): δ 6.65-6.45 (m, 4H, aromatic), δ 4.23 (s, 2H, CH 2 ), δ 2.68 (s, 6H, NCH 3 ). 1 H NMR (6) (HX=acetic acid, CD 3 CN, 25° C, 400 MHz): δ 10.81 (s, CH 3 CO 2 ), δ 9.07 (s, 1H, NCHN), δ 7.85-7.69 (m, 4H, aromatic), δ 4.05 (s, 6H, NCH 3 ), δ 1.96 (s, CH 3 CO 2 ). EXAMPLE 8 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that CpRuH(PPh 3 ) 2 (Cp=cyclopentadienyl=C 5 H 5 ) was used instead of RhCl(PPh 3 ) 3 . EXAMPLE 9 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that CpRuH(dppe) (dppe=diphenylphosphinoethane) was used instead of RhCl(PPh 3 ) 3 . EXAMPLE 10 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that RuCl 2 (PPh 3 ) 3 was used instead of RhCl(PPh 3 ) 3 . EXAMPLE 11 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that Pt(CH 3 ) 2 (COD) (COD=cyclooctadiene) was used instead of RhCl(PPh 3 ) 3 . EXAMPLE 12 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that Rh(CO)Cl(PPh 3 ) 2 was used instead of RhCl(PPh 3 ) 3 . EXAMPLE 13 Conversion of (5) to (6) in the presence of acid and a heterogeneous catalyst. A solution of compound (5) (15 mg, 0.10 mmol), acetic acid (60 mg, 1.0 mmol) and CD 3 CN (0.7 ml) was prepared in an NMR tube. The solution was mixed, and Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added. Effervescence began immediately upon addition of the Pd(O 2 CCH 3 ) 2 . Complete conversion of compound (5) to compound (6) (X═CH 3 COO − ) was confirmed by 1 H NMR spectroscopy after 30 minutes at room temperature. EXAMPLE 14 Catalytic dehydrogenation of compound (5) in the presence of D 2 O and a heterogeneous catalyst. A solution of compound (5) (15 mg, 0.10 mmol) in a 1:1 mixture of D 2 O:CD 3 OD (0.7 ml) solvent was prepared in an NMR tube. This solution was mixed, Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added, and the resulting mixture was heated to a temperature of about 70 degrees Celsius for about one hour. Effervescence was observed. About a 15 percent conversion of compound (5) to compound (6) (X═OD − ) after about one hour was confirmed by 1 H NMR spectroscopy. EXAMPLE 15 Catalytic dehydrogenation of compound (5) in the presence of D2O, sodium bicarbonate, and a heterogeneous catalyst. A solution of compound (5) (15 mg, 0.10 mmol) and NaHCO3 (0.12 mmol) in a 1:1 mixture of D 2 O:CD 3 OD (0.7 ml) solvent was prepared in an NMR tube. The solution was mixed, Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added, and the resulting mixture was heated to a temperature of about 70 degrees Celsius for about one hour. Effervescence was observed. 1 H NMR indicated that the conversion from compound (5) to compound (6) (X=bicarbonate or carbonate) was about 15 percent after about one hour. The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiment(s) were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
A method and system for storing and evolving hydrogen employ chemical compounds that can be hydrogenated to store hydrogen and dehydrogenated to evolve hydrogen. A catalyst lowers the energy required for storing and evolving hydrogen. The method and system can provide hydrogen for devices that consume hydrogen as fuel.
Provide a concise summary of the essential information conveyed in the context.
[ "RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application Ser.", "No. 60/581,914 filed Jun. 22, 2004, and U.S. Provisional Patent Application Ser.", "No. 60/616/085 filed Oct. 5, 2004, both hereby incorporated by reference.", "STATEMENT REGARDING FEDERAL RIGHTS This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy.", "The government has certain rights in the invention.", "FIELD OF THE INVENTION The present invention relates generally to hydrogen evolution and storage and more particularly to a method and system for storing and evolving hydrogen.", "BACKGROUND OF THE INVENTION Hydrogen (H 2 ) is currently the leading candidate for a fuel to replace gasoline/diesel fuel in powering the nation's transportation fleet.", "There are a number of difficulties and technological barriers associated with hydrogen that must be solved in order to realize this “hydrogen economy.”", "Inadequate storage systems for on-board transportation hydrogen are recognized as a major technological barrier (see, for example, “The Hydrogen Economy: Opportunities, Costs, Barriers, and R&D Needs,” National Academy of Engineering (NAE), Board on Energy and Environmental Systems, National Academy Press (2004).", "One of the general schemes for storing hydrogen relates to using a chemical compound or system that undergoes a chemical reaction to evolve hydrogen as a reaction product.", "In principle, this chemical storage system is attractive, but all practical systems that have been studied to date involve either: (a) hydrolysis of high-energy inorganic compounds where the evolution of hydrogen is very exothermic (sodium borohydride/water as in the Millennium Cell's HYDROGEN ON DEMAND®, and lithium hydride as in SAFE HYDROGEN®, for example), thus making the cost of preparing the inorganic compound(s) high and life-cycle efficiency low;", "or (b) dehydrogenation of inorganic hydride materials (such as Na 3 AlH 6 /NaAlH 4 , for example) that release hydrogen when warmed but that typically have inadequate mass storage capacity and inadequate refueling rates.", "Inorganic compounds referred to in (a), above, produce hydrogen according to the chemical reaction MH x +XH 2 O→M(OH) x +XH 2 (1) where MH x is a metal hydride, and M(OH) x is a metal hydroxide.", "This reaction is irreversible.", "Inorganic hydride materials referred to in (b), above, produce hydrogen according to following chemical reaction, which is reversible with H 2 (hydrogen gas): MH x =M+ x /2H 2 (2) where MH x is a metal hydride, M is metal and H 2 is hydrogen gas.", "By contrast to the first reaction, which is irreversible with H 2 , the second reaction is reversible with H 2 .", "A practical chemical system that evolves hydrogen yet does not suffer the aforementioned inadequacies would be important to the planned transportation sector of the hydrogen economy.", "This same practical chemical system would also be extremely valuable for non-transportation H 2 fuel cell systems, such as those employed in laptop computers and other portable electronic devices, and in small mechanical devices such as lawnmowers where current technology causes significant pollution concerns.", "Any heat that must be input to evolve the hydrogen represents an energy loss at the point of use, and any heat that is evolved along with the hydrogen represents an energy loss where the chemical storage medium is regenerated.", "Either way, energy is lost, which diminishes the life-cycle efficiency.", "For most organic compounds, such as in those shown in equations 3-5 below, hydrogen evolution reactions are very endothermic, and the compounds are incompetent to evolve hydrogen at ambient temperature (i.e. thermodynamically incapable of evolving H 2 at significant pressure at ambient temperature).", "For temperatures less than about 250-400 degrees Celsius, the equilibrium pressure of hydrogen over most organic compounds is very small.", "As a consequence, most common organic compounds require heating above about 250 degrees Celsius, and the continual input of high-grade heat to maintain this temperature, in order to evolve hydrogen at a useful pressure.", "CH 4 → C + 2 H 2 ΔH 0 = +18 kcal/mol (3) ΔG 0 = +12 kcal/mol 6 CH 4 → cyclohexane + 6 H 2 ΔH 0 = +69 kcal/mol (4) ΔG 0 = +78 kcal/mol cyclohexane → benzene + 3 H 2 ΔH 0 = +49 kcal/mol (5) ΔG 0 = +23 kcal/mol Most organic compounds have hydrogen evolution reactions that are endergonic (i.e. having a net positive free energy of reaction change, i.e. ΔG>0) and their ambient temperature equilibrium hydrogen pressure is very low, practically unobservable.", "Thus, most organic compounds are unsuitable for hydrogen storage, based on both life-cycle energy efficiency and delivery pressure considerations.", "Decalin, for example, evolves hydrogen to form naphthalene when heated to about 250 degrees Celsius in the presence of a catalyst (see, for example, “Catalytic Decalin Dehydrogenation/Naphthalene Hydrogenation Pair as a Hydrogen Source for Fuel-Cell Vehicle,” S. Hodoshima, H. Arai, S. Takaiwa, and Y. Saito, Int.", "J. Hydrogen Energy (2003) vol.", "28, pp[.", "].1255-1262, incorporated by reference herein).", "Hodoshima et al.", "use a superheated “thin film”", "reactor that operates at a temperature of at least 280 degrees Celsius to produce hydrogen from decalin at an adequate rate.", "Thus, this endothermic hydrogen evolution reaction requires both a complex apparatus and high-grade heat, which diminishes the life-cycle energy efficiency for hydrogen storage.", "Methods and systems that employ chemical compounds for storing and evolving hydrogen at ambient temperature with minimal heat input remain highly desirable.", "Therefore, an object of the present invention is a method for evolving hydrogen that is thermodynamically more favored than previously-described systems.", "Another object of the present invention is a thermodynamically favorable system for evolving hydrogen.", "Another object of the present invention is a reversible system for evolving and storing hydrogen.", "Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention.", "The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.", "SUMMARY OF THE INVENTION In accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention includes a method for producing hydrogen.", "The method involves exposing at least one chemical compound to a catalyst under conditions suitable for dehydrogenating the at least one chemical compound to form at least one product, the at least one chemical compound having the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure;", "and with the proviso that X and X′ cannot both be oxygen.", "The invention also includes a method for producing hydrogen, and involves exposing at least one chemical compound to a catalyst under conditions suitable for chemical reaction that forms hydrogen.", "The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "wherein R 8 and R 9 may be connected to each other to form a ring structure;", "and with the proviso that at least one of R 5 or R 11 is hydrogen.", "The invention also includes a method for producing hydrogen, comprising exposing at least one chemical compound and an acid to a catalyst under conditions suitable for chemical reaction that forms hydrogen.", "The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The acid may be an alcohol, a phenol, or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid can be water);", "and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine, quinoline, ammonia, and amine.", "The invention also includes a system for producing hydrogen.", "The system includes at least one organic compound, an acid, and a catalyst suitable for facilitating a chemical reaction between the at least one chemical compound and the acid in order to form hydrogen.", "The chemical compound has the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The acid may be an alcohol, a phenol, or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid can be water);", "and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine, quinoline, ammonia, and amine.", "The invention also includes a system for producing hydrogen.", "The system includes at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a system for producing hydrogen.", "The system includes at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl;", "wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2;", "wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl, aryl;", "and wherein R 3 is selected from hydrogen, alkyl, aryl.", "The system also includes a catalyst suitable for facilitating the dehydrogenation of the chemical compound.", "The invention also includes a system for producing hydrogen.", "The system includes a chemical compound having the formula wherein each R is independently selected from hydrogen, alkyl, and aryl;", "and a catalyst suitable for facilitating the dehydrogenation of the chemical compound.", "The invention also includes a system for producing hydrogen comprising a chemical compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group;", "and a catalyst suitable for facilitating the dehydrogenation of the chemical compound.", "The invention also includes a system for producing hydrogen comprising a chemical compound having the formula wherein Q is N or (C(R));", "wherein each R is independently selected from hydrogen, alkyl, aryl, and a higher fused ring group;", "and a catalyst suitable for facilitating the dehydrogenation of said chemical compound.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode.", "The hydrogen-generating fuel source includes at least one chemical compound and a catalyst suitable for dehydrogenating the chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure.", "The invention also includes a fuel cell comprising an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl;", "wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2;", "wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl and aryl;", "and wherein R 3 is selected from hydrogen, alkyl, aryl.", "The invention also includes a method for storing hydrogen.", "The method involves exposing at least one chemical compound to hydrogen in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has an anion and cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a method for storing hydrogen, which includes exposing at least one chemical compound to a reducing agent, the chemical compound having an anion and a cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a method for storing hydrogen, and involves exposing at least one chemical compound to hydrogen or to a reducing agent in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure;", "and with the proviso that X and X′ cannot both be oxygen.", "DETAILED DESCRIPTION The present invention relates to a chemical system useful for chemical hydrogen storage.", "Using the chemical system of the invention, hydrogen (H 2 ) is evolved without significant input or evolution of heat.", "One aspect of the present invention relates to hydrogen evolution from chemical compounds according to equation 6: wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure;", "and with the proviso that X and X′ cannot both be oxygen.", "For equation 6, it is believed that the ΔH 0 varies from about +10 kcal/mole to about −2 kcal/mole, and the ΔG 0 varies from about +5 kcal/mole to about −10 kcal/mole.", "Thus, the chemical reaction for hydrogen evolution as shown in Equation 6 above is nearly thermoneutral, perhaps even slightly exothermic, based on the currently available thermodynamic data for these materials.", "Owing to the favorable entropy of hydrogen evolution, the reaction can become exergonic (having a standard free energy change, ΔG 0 , of less than zero) and the ambient temperature equilibrium pressure of hydrogen approaches or exceeds the DOE target of 3 atmospheres.", "If the chemical compound is stabilized against classical functional group elimination by, for example, the presence of additional atoms that join to form a ring structure, then it is expected that the hydrogen evolution and hydrogenation will be reversible in the presence of a suitably active catalyst that selectively catalyzes the hydrogen evolution reaction and also the reverse reaction (i.e. the hydrogenation reaction).", "Such reversibility is advantageous because it allows the chemical compound to be regenerated simply by hydrogenation under pressure, and the energy cost of regenerating the chemical compound is likely to be minimal.", "Another aspect of the invention is related to a method and chemical system for producing hydrogen.", "This aspect of the invention involves exposing one or more chemical compounds to a catalyst under conditions suitable for a chemical reaction that forms hydrogen.", "Chemical compounds that evolve hydrogen according to the present invention include those having the chemical formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "wherein R 8 and R 9 may be connected to each other to form a ring structure;", "and with the proviso that at least one of R 5 or R 11 is hydrogen.", "When Q is —(C(R 7 R 8 )) n — where n is greater than one, and when Q is —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, the invention is meant to include structures where R 7 and R 8 in one C(R 7 R 8 ) grouping might be the same, but are not necessarily the same, as the R 7 and R 8 in another C(R 7 R 8 ) grouping.", "Structures such as the one shown below on the right, for example, where n is two and where R 7 and R 8 in one grouping are H and methyl, and are ethyl and phenyl in another grouping, are invention structures.", "An embodiment system including a chemical compound exemplary of the above formula was used to demonstrate this aspect of the present invention, and is shown in equation 7 below.", "While not intending to be bound by any particular explanation, it is believed that the compound shown on the top left of equation 7 tautomerizes to the zwitterionic form shown on the bottom left and that hydrogen evolution from either of these forms produces the species shown on the right.", "The hydrogen evolution reaction is a classically “symmetry forbidden”", "reaction.", "Therefore, the hydrogen evolution reaction is typically very slow in the absence of a suitable catalyst.", "Examples of catalysts that may facilitate hydrogen evolution include, for example, rhodium or ruthenium-based hydrogen transfer catalysts, ruthenium-based formic acid decomposition catalysts, nickel/copper/zinc-based reformation/hydrogenation catalysts, and the like.", "Catalysts useful with the present invention also include various forms of palladium, such as finely divided palladium metal, palladium supported on carbon, palladium supported on alumina, palladium supported on silica, a slurry of palladium in a solvent, a fluidized bed comprising palladium, a packed bed comprising palladium, or palladium carboxylate.", "For the system shown in equation 7, hydrogen evolution was observed in the presence of a palladium catalyst at a reaction temperature of from room temperature to about 60-70 degrees Celsius (a temperature range of from about 20 degrees Celsius to about 250 degrees Celsius will facilitate the reaction).", "Interestingly, in the absence of the catalyst, the compound shown top left does not evolve hydrogen after heating at 185 degrees Celsius for 8 days (see P. Brunet and J. D. Wuest “Formal Transfers of Hydride from Carbon-Hydrogen Bonds. Attempted Generation of H 2 by Intramolecular Protonolysis of the Activated Carbon-Hydrogen Bonds of Dihydrobenzimidazoles,” Can.", "J. Chem.", "(1996) vol.", "74, p. 689).", "The system shown in equation 7 employs an acidic functional group.", "Other aspects of this invention relate to a method and system that relate to chemical compounds that may, but do not necessarily include acidic functional groups.", "Compounds of this type could be used with a catalyst and separate acid.", "This aspect of the invention relates to evolving hydrogen by exposing at least one chemical compound and an acid to a catalyst under conditions suitable for chemical reaction that forms hydrogen.", "Chemical compounds of this type have the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are independently selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The acid can be an alcohol (methyl alcohol, ethyl alcohol, trifluoromethyl alcohol, and the like), a phenol (phenol, resorcinol, catechol, naphthol, and the like), or a compound having the formula HX or the formula HTX, wherein X is selected from chloride, bromide, iodide, carboxylate, sulfonate, phosphate, phosphonate, sulfate, and hydroxide (i.e. the acid may be water);", "and wherein T is selected from imidazole, alkylimidazole, arylimidazole, benzimidazole, alkylbenzimidazole, oxazole, alkyloxazole, benzoxazole, pyrazole, alkylpyrazole, arylpyrazole, pyridine, alkylpyridine, arylpyridine quinoline, ammonia, and amine.", "Some examples of an acid HX useful with this invention include, but are not limited to, acetic acid, succinic acid, benzoic acid, and acrylic acid.", "Preferably, the compound and/or the acid HX or HTX is (are) chosen such that the change in the standard free energy of the chemical reaction comprises a standard free energy in the range of from about +5 kilocalories per mole to about −10 kilocalories per mole.", "The compound may be dissolved in a solvent chosen to stabilize the at least one organic compound and any cationic reaction products derived therefrom, so that the change in the standard free energy of the chemical reaction comprises a standard free energy in the range of from about +5 kilocalories per mole to about −10 kilocalories per mole.", "Examples of solvents useful with the present invention include polar organic and inorganic solvents such as, but not limited to, water, acetonitrile, tetrahydrofuran, pyridine, dimethylsulfoxide (DMSO), dimethylformamide (DMF), acetone, methyl ethyl ketone, methanol, ethanol, isopropanol, and the like.", "Ionic liquid solvents, also know in the art as “molten salts,” may also be used as solvents.", "Ionic liquids useful with this invention have been described, for example, in PCT Patent Application WO 01/93363 to A. McEwen et al.", "entitled “Non-Flammable Electrolytes”;", "in Japanese Patent 98168028 to M. Watanabe et al.", "entitled “Room Temperature Molten Salts and Electrochemical Devices Using the Salts”;", "in U.S. Pat. No. 6,365,301 to C. Michot et al.", "entitled “Materials Useful as Electrolytic Solutes,” which issued on Apr. 2, 2002;", "in “Room Temperature Ionic Liquids of Alkylimidazolium Cations and Fluoroanions”", "by R. Hagiwara and Y. Ito, J. Fluorine Chem.", "vol[.", "].105, (2000), pp. 221-227;", "in “Room-Temperature Molten Salts Based on the Quaternary Ammonium Ion”", "by J. Sun, M. Forsyth, and D. R. MacFarlane, J. Phys.", "Chem.", "B, 1998, vol[.", "].102, pages 8858-8864;", "and in U.S. Pat. No. 5,827,602 to V. R. Koch et al.", "entitled “Hydrophobic Ionic Liquids,” which issued Oct. 27, 1998, all incorporated by reference herein.", "Another aspect of this invention relates to a method and system for producing hydrogen that employs compounds having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl;", "wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2;", "wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl, aryl;", "and wherein R 3 is selected from hydrogen, alkyl, aryl.", "The system also includes a catalyst suitable for facilitating the dehydrogenation of the chemical compound.", "Another aspect of the present invention is related to hydrogen storage, and involves exposing at least one chemical compound to a hydrogen in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which includes anion and cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a method for storing hydrogen, which includes exposing at least one chemical compound to a reducing agent, the chemical compound having an anion and a cationic portion having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and −N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The reducing agents may one or more of lithium borohydride, sodium borohydride, potassium borohydride, sodium hydride, potassium hydride, magnesium hydride, lithium hydride, calcium hydride, and electron plus proton where the electron can be provided by a metal reducing agent (zinc, for example).", "The invention also includes a method for storing hydrogen, and involves exposing at least one chemical compound to hydrogen or to a reducing agent in the presence of a catalyst that facilitates the hydrogenation of the at least one chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure;", "and with the proviso that X and X′ cannot both be oxygen.", "Another example of a system for hydrogen evolution and storage is related to chemical compounds known generally as triazacyclohexanes, which are also known in the art as hexahydrotrazines.", "These materials evolve hydrogen and a product known more generally as a triazine.", "In this system, three molecules of hydrogen may be produced from one molecule of the triazacyclohexane.", "The amount of evolvable hydrogen for trazacyclohexane is 6.9 weight percent.", "The dehydrogenation reaction is slightly endothermic (ΔH=+17 kcal/mole by calculation) and exergonic (ΔG=−9 kcal/mole by calculation).", "Examples of these types of materials that can be used to produce a hydrogen evolving system of the invention include, for example, a compound having the formula wherein each R is independently selected from hydrogen, alkyl, and aryl;", "and a compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group;", "and a compound having the formula wherein each R is independently selected from hydrogen, alkyl, aryl and a higher fused ring group.", "For these compounds, a catalyst is included for facilitating the dehydrogenation of the chemical compound.", "The method and system of the present invention can be used with a fuel cell to provide power to portable devices such as laptop or handheld computers, cellular phones, global positioning system receivers, CD/MP3 music players, flashlights, and the like, and vehicles.", "The following details relate to aspects of the invention that relate to fuel cells.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode.", "The hydrogen-generating fuel source includes at least one chemical compound and a catalyst suitable for dehydrogenating the chemical compound, which has the formula wherein X is oxygen, —N(H)—, or —N(R 3 )—;", "wherein X′ is oxygen, —N(H)— or —N(R 4 )—;", "wherein R 1 , R 2 , R 3 , and R 4 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl sulfonic acid, alkenyl phosphoric acid, and alkenyl phosphonic acid;", "and wherein R 1 and R 3 can be connected to each other to form a ring structure.", "The invention also includes a fuel cell comprising an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, or —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )—;", "wherein R 5 and R 11 are independently selected from hydrogen, alkyl, and aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl.", "phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ).", "wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "wherein R 8 and R 9 may be connected to each other to form a ring structure;", "and with the proviso that at least one of R 5 or R 11 is hydrogen.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Q is —(C(R 7 R 8 )) n — where n is from 1 to 10, —(C(R 7 R 8 )-M-C(R 7 R 8 ))—, —(C(R 7 )═C(R 8 ))—, —(C(R 7 )═C(R 8 )—C(R 9 )═C(R 10 ))—, —(C(R 7 )═N)—, —(C(R 7 )═N—C(R 8 )═N)—;", "wherein M is oxygen, —NR 9 —, sulfur, or —C(═O)—;", "wherein Z is oxygen, sulfur, or —N(R 11 )— wherein R 11 is hydrogen, alkyl, or aryl;", "wherein R 7 , R 8 , R 9 , and R 10 are independently selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid;", "wherein R 6 is selected from hydrogen, alkyl, aryl, alkenyl, alkyl carboxylic acid, alkyl sulfonic acid, alkyl phosphoric acid, alkyl phosphonic acid, aryl carboxylic acid, aryl sulfonic acid, aryl phosphoric acid, aryl phosphonic acid, alkenyl carboxylic acid, alkenyl phosphoric acid, alkenyl phosphonic acid, —OR 12 , —N(H)(R 12 ) and —N(R 12 R 13 ) wherein R 12 and R 13 are selected from hydrogen, alkyl and aryl;", "wherein R 7 and R 8 may be connected to each other to form a ring structure;", "and wherein R 8 and R 9 may be connected to each other to form a ring structure.", "The invention also includes a fuel cell having an anode and a hydrogen-generating fuel source for the anode, the hydrogen generating fuel source including at least one chemical compound having the formula wherein Z is selected from oxygen, sulfur, or —N(R 4 )— where R 4 is alkyl or aryl;", "wherein Q is selected from oxygen, —N(R 5 )—, —(C(R 5 R 6 )) n — where n is from 1 to 10, —(C(R 5 )═C(R 6 )) m — where m is from 1 to 2, and —(C(R 5 )═N) p — where p is from 1 to 2;", "wherein R 1 , R 2 , R 4 , R 5 , and R 6 are selected independently from alkyl and aryl;", "and wherein R 3 is selected from hydrogen, alkyl, aryl.", "With a suitable catalyst, the hydrogen reaction becomes reversible, allowing the organic compounds to function as reversible hydrogen carriers that are capable of carrying hydrogen from one region of a device to another.", "The following EXAMPLES illustrate embodiments of the present invention.", "EXAMPLE 1 Catalytic dehydrogenation of A solution of compound 1 (9 mg, 0.03 mmol) in CD 3 CN (0.7 ml) was prepared in a nuclear magnetic resonance (NMR) tube.", "Palladium acetate (Pd(O 2 CCH 3 ) 2 , 1 mg, 0.003 mmol) was added to the tube.", "Upon mixing, a black precipitate formed and effervescence was observed.", "The reaction mixture was then heated to a temperature of about 70 degrees Celsius for about 30 minutes, resulting in a 90 percent conversion of (1) to which was confirmed by 1 H NMR spectroscopy.", "1 H NMR (1) (THF-d 8 , 25° C., 400 MHz): δ 8.08 (d, 1H, aromatic), δ 7.83 (d, 1H, aromatic), δ 7.53 (t, 1H, aromatic), δ 6.56 (m, 2H, aromatic), δ 6.31 (m, 2H, aromatic), δ 6.00 (s, 1H, RN 2 CH), δ 2.50 (s, 6H, CH 3 ).", "1 H NMR (2) (CD 3 CN, 25° C., 400 MHz): δ 8.23 (d, 1H, aromatic), δ 7.77 (m, 2H, aromatic), δ 7.72 (t, 1H, aromatic), δ 7.60 (m, 3H, aromatic), δ 7.40 (d, 1H, aromatic), δ 3.52 (s, 6H, CH 3 ).", "Evolution of molecular hydrogen from compound (1) was confirmed by catalytic hydrogenation of trans-stilbene with the hydrogen evolved from compound (1).", "In an experimental set-up, a flask was charged with compound (1) (50 mg, 0.18 mmol) and Pd(O 2 CCH 3 ) 2 (3 mg, 0.013 mmol) in acetonitrile.", "A separate flask was charged with trans-stilbene (34 mg, 0.18 mmol) and 10% Pd on carbon (20 mg) in benzene.", "The headspaces of the two flasks were immediately connected with a transfer tube.", "After about 12 hours, the contents of both flasks were analyzed using 1 H NMR spectroscopy.", "Complete conversion of compound (1) to compound (2) was observed for the first flask.", "Hydrogenation of the trans-stilbene in the second flask was 47% complete, confirming the evolution of hydrogen from compound (1).", "EXAMPLE 2 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that Pearlman's catalyst (Pd(OH) 2 /C) was used instead of palladium acetate.", "EXAMPLE 3 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that Pd/C was used instead of palladium acetate.", "EXAMPLE 4 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that PdCl 2 (bipyridine) was used instead of palladium acetate.", "EXAMPLE 5 Compound (1) was converted to compound (2) according to the procedure described in EXAMPLE 1, with the exception that K 2 PdCl 4 was used instead of palladium acetate.", "EXAMPLE 6 Catalytic dehydrogenation of in the presence of acid.", "A solution of compound (3) in CD 3 CN (0.7 ml) solvent was prepared in an NMR tube.", "Acetic acid (0.015 ml, 0.26 mmol) was added to the solution and the contents were mixed thoroughly.", "Palladium acetate (1 mg, 0.003 mmol) was then added to the mixture, after which a black precipitate formed and effervescence was observed.", "The NMR tube was heated to a temperature of about 70 degrees Celsius for about 30 minutes, resulting in complete conversion of compound 3 to (X═CH 3 COO − ), which was confirmed by 1 H NMR spectroscopy.", "1 H NMR (3) (CD 3 CN, 25° C., 400 MHz): δ 7.56-7.45 (m, 5H, aromatic), δ 6.66-6.44 (m, 4H, aromatic), δ 4.84 (s, 1H, N 2 RCH), δ 2.50 (s, 6H, NCH 3 ).", "1 H NMR (4) (HX=acetic acid, CD 3 CN, 25° C., 300 MHz): δ 8.0-7.6 (m, 9H, aromatic), δ 3.87 (s, 6H, CH 3 N), δ 1.80 (s, 3H, CH 3 CO 2 ).", "EXAMPLE 7 Catalytic dehydrogenation of in the presence of acid and a homogeneous catalyst.", "A solution of compound 5 (15 mg, 0.10 mmol), acetic acid (60 mg, 1.0 mmol) and CD 3 CN (0.70 ml) was prepared in an NMR tube.", "The solution was mixed, after which RhCl(PPh 3 ) 3 (0.3 mg, 0.37 μmol, Ph═C 6 H 5 ) was added to the solution.", "The mixture was heated at a temperature of about 70 degrees Celsius for about one hour, resulting in a 43% conversion of compound (5) to (X═CH 3 COO − ), which was confirmed by 1 H NMR spectroscopy.", "Turnover number (TON)=117 at 70° C. in 1 hour.", "1 H NMR (5) (CD 3 CN, 25° C., 400 MHz): δ 6.65-6.45 (m, 4H, aromatic), δ 4.23 (s, 2H, CH 2 ), δ 2.68 (s, 6H, NCH 3 ).", "1 H NMR (6) (HX=acetic acid, CD 3 CN, 25° C, 400 MHz): δ 10.81 (s, CH 3 CO 2 ), δ 9.07 (s, 1H, NCHN), δ 7.85-7.69 (m, 4H, aromatic), δ 4.05 (s, 6H, NCH 3 ), δ 1.96 (s, CH 3 CO 2 ).", "EXAMPLE 8 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that CpRuH(PPh 3 ) 2 (Cp=cyclopentadienyl=C 5 H 5 ) was used instead of RhCl(PPh 3 ) 3 .", "EXAMPLE 9 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that CpRuH(dppe) (dppe=diphenylphosphinoethane) was used instead of RhCl(PPh 3 ) 3 .", "EXAMPLE 10 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that RuCl 2 (PPh 3 ) 3 was used instead of RhCl(PPh 3 ) 3 .", "EXAMPLE 11 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that Pt(CH 3 ) 2 (COD) (COD=cyclooctadiene) was used instead of RhCl(PPh 3 ) 3 .", "EXAMPLE 12 Compound (5) was converted to compound (6) according to the procedure described in EXAMPLE 7 with the exception that Rh(CO)Cl(PPh 3 ) 2 was used instead of RhCl(PPh 3 ) 3 .", "EXAMPLE 13 Conversion of (5) to (6) in the presence of acid and a heterogeneous catalyst.", "A solution of compound (5) (15 mg, 0.10 mmol), acetic acid (60 mg, 1.0 mmol) and CD 3 CN (0.7 ml) was prepared in an NMR tube.", "The solution was mixed, and Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added.", "Effervescence began immediately upon addition of the Pd(O 2 CCH 3 ) 2 .", "Complete conversion of compound (5) to compound (6) (X═CH 3 COO − ) was confirmed by 1 H NMR spectroscopy after 30 minutes at room temperature.", "EXAMPLE 14 Catalytic dehydrogenation of compound (5) in the presence of D 2 O and a heterogeneous catalyst.", "A solution of compound (5) (15 mg, 0.10 mmol) in a 1:1 mixture of D 2 O:CD 3 OD (0.7 ml) solvent was prepared in an NMR tube.", "This solution was mixed, Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added, and the resulting mixture was heated to a temperature of about 70 degrees Celsius for about one hour.", "Effervescence was observed.", "About a 15 percent conversion of compound (5) to compound (6) (X═OD − ) after about one hour was confirmed by 1 H NMR spectroscopy.", "EXAMPLE 15 Catalytic dehydrogenation of compound (5) in the presence of D2O, sodium bicarbonate, and a heterogeneous catalyst.", "A solution of compound (5) (15 mg, 0.10 mmol) and NaHCO3 (0.12 mmol) in a 1:1 mixture of D 2 O:CD 3 OD (0.7 ml) solvent was prepared in an NMR tube.", "The solution was mixed, Pd(O 2 CCH 3 ) 2 (1 mg, 0.003 mmol) was added, and the resulting mixture was heated to a temperature of about 70 degrees Celsius for about one hour.", "Effervescence was observed.", "1 H NMR indicated that the conversion from compound (5) to compound (6) (X=bicarbonate or carbonate) was about 15 percent after about one hour.", "The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching.", "The embodiment(s) were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.", "It is intended that the scope of the invention be defined by the claims appended hereto." ]
CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional application of U.S. application Ser. No. 11/229,022, filed on Sep. 16, 2005, now U.S. Pat. No. 7,473,354. BACKGROUND OF THE INVENTION The present invention relates to ion chromatography systems for determination of both anionic and cationic analytes. Ion chromatography is a widely used analytical technique for the determination of anionic and cationic analytes in various sample matrices. Ion chromatography, also called suppressed ion chromatography, includes a chromatographic separation stage using an eluent containing an electrolyte, an eluent suppression stage, followed by the detection stage, typically using an electrical conductivity detector. In the chromatographic separation stage, ionic analytes of an injected sample are eluted through a separation column and separated from each other using an electrolyte as the eluent. In the suppression stage, an eluent suppression device, or suppressor, is the critical system component used to convert the eluent into a weakly conducting form and enhance the conductance of target analytes. This technique has been described in detail in U.S. Pat. Nos. 3,897,213, 3,920,397, 3,925,019, and 3,926,559. Even though ion chromatography today comprises a number of separation and detection modes, ion chromatography with suppressed conductivity detection remains the most widely practiced form of the technique. The original suppressors were columns packed with ion-exchange resins in appropriate ionic forms. Those packed-bed suppressors had a relatively large dead volume and required frequent off-line chemical regeneration. To overcome this problem, suppressors based on ion-exchange fibers and membranes were developed. Over the years, several designs of electrolytically-regenerated membrane suppressors as described in U.S. Pat. Nos. 4,999,098, 5,248,426, 5,352,360, and 6,325,976 have been also developed to overcome the limitations associated with the chemically-regenerated membrane suppressors. The electrolytic suppressors offer several advantages in ion chromatography. They provide continuous and simultaneous suppression of eluents, regeneration of the suppression bed, and sufficient suppression capacity for all common IC applications. They are easy to operate because either the suppressed eluent or water is used to create regenerant ions electrolytically, and there is no need to prepare regenerant solutions off-line. They are compatible with gradient separations. They have very low suppression zone volume, which makes it possible to achieve separations with very high chromatographic efficiency. In the operation of electrolytically-regenerated membrane suppressors, it is sometimes preferred to operate the electrolytic membrane suppressors in the external water mode because the type of detector used is not amenable to the recycle mode of operation or because lower suppressed background noise achievable in the external water mode of operation is desirable. The external water regenerant is typically operated at flow rates that are 2 to 10 times higher than the eluent flow rate and thus typically consume a significant amount of water regenerant. For example, a total of 2628 liters of water is required if an ion chromatography system is operated continuously at a separation flow rate of 1.0 mL/min and the water regenerant is operated at 5 mL/min and 24 hours per day for 365 day per year. When a constant supply of large amounts of high purity water from an external source is required for continuous operation, the IC system operators face the waste disposal and other logistical challenges to system operation. Even though the use of chemically-regenerated membrane suppressors have decreased somewhat in recent years, the membrane suppressors offer the benefits of long lifetime, low noise, and better compatibility with applications where organic solvents are used as in the eluents. In the operation of chemically-regenerated membrane suppressors, an external source of either acid or base regenerant solution is required to generate the suppressor continuously. The external acid or base regenerant is typically operated at flow rates that are 2 to 10 times higher than the eluent flow rate and thus typically consume a significant amount of regenerants. The consistent preparation of such large amount of the regenerant as well as the disposal of the used regenerant can pose serious logistical challenges to the system operators in terms of costs and labor, especially in cases where unattended or less frequently attended operations are required. There is a need to minimize waste disposal, and reduce operating costs of the regenerant solutions used in the operation of both the chemically-regenerated and electrolytically-regenerated suppressors. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-6 are schematic representations of different suppressed ion chromatography systems with recycled eluents according to the present invention. FIG. 7 is a chromatogram illustrating the present invention. FIGS. 8 and 9 illustrate reproducibility data using the present invention. SUMMARY OF THE INVENTION In one embodiment, the invention is a suppressed ion chromatographic apparatus using a regenerant recycle loop, comprising (a) an ion separation device including ion separation medium with exchangeable ions of one charge, positive or negative, (b) a membrane suppressor comprising a sample stream flow channel, having an inlet and an outlet, a regenerant flow channel, having an inlet and an outlet, and an ion exchange membrane separating the sample stream flow channel and regenerant flow channel, (c) a detector having an inlet and an outlet, the detector inlet being in fluid communication with the sample stream flow channel outlet, (d) a container for regenerant solution, (e) a first conduit providing fluid communication between the ion separation device and the sample stream flow channel inlet, (f) a second conduit providing fluid communication between the regenerant solution container and the regenerant flow channel, (g) a third conduit providing fluid communication between the regenerant channel and the regenerant solution container, and (h) a regenerant solution recycle loop comprising the second and third conduits, the recycle loop being out of fluid communication with the detector outlet. In another embodiment, the invention is a method for suppressed ion chromatography using a regenerant solution recycle loop, comprising (a) separating sample ions of one charge, positive or negative, in a liquid sample stream including eluent by flowing the same through ion separation medium in an ion separation device, (b) suppressing the eluent by flowing the effluent from the ion separation medium through a sample stream flow channel of a membrane suppressor comprising a sample stream flow channel, having an inlet and an outlet, a regenerant flow channel, having an inlet and an outlet, and an ion exchange membrane separating the sample stream flow channel and regenerant flow channel, (c) detecting the separated sample ions by flowing the effluent from the sample stream flow channel through a detector, (d) flowing a regenerant solution through the regenerant flow channel, (e) providing a regenerant solution reservoir, and (f) flowing the regenerant solution between the regenerant solution reservoir and the regenerant flow channel in a recycle loop independent of liquid flow through the detector. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to various modes of recycling either (1) the regenerants such as water used in the operation of the electrolytically-regenerated suppressors when they are operated in the external water mode, or (2) acid or base regenerants used in the operation of chemically-regenerated suppressors. Referring to FIG. 1 , the invention will first be described in the recycled water mode used in the operation of the electrolytically-regenerated suppressors when they are operated in the external water mode. FIG. 1 illustrates the basic components of one of the preferred embodiments of ion chromatography system using recycled suppressor regenerant water. In this embodiment, an eluent generator 10 of the type illustrated in FIG. 1 of U.S. Pat. No. 6,682,701 is used with some modification as described below. Other eluent generators such as illustrated in the '701 patent can be used in combination with the ion chromatography system of the present invention. The principles of operation of the electrolytic eluent generator are fully described in U.S. Pat. No. 6,682,701. Other electrolytic eluent generators may be used such as ones which generate a carbonate salt such as potassium carbonate illustrated in PCT Application WO/2004/024302. In this instance, the ion chromatography system downstream from the eluent generator also is as illustrated in FIG. 1 . Other eluent generators can be used, e.g. as illustrated in U.S. Pat. Nos. 5,045,204 or 6,562,628. Although the eluent generators are illustrated for anion analysis and the generation of cations such as potassium ions, for cation analysis, the same system may be used for generating MSA or other anions for an acid eluent by appropriate reversal of the polarity of the membrane ion exchange resin and electrodes such as illustrated in U.S. Pat. No. 6,682,701. Referring specifically to the embodiment of FIG. 1 , illustrated for the analyses of anions, deionized water 12 from a source, not shown, is pumped under pressure supplied by pump 14 , through the high pressure base generation chamber 16 of electrolytic generator 10 . As illustrated, chamber 16 includes a cathode 18 in communication with a cation exchange bed. The high pressure base generation chamber is separated by a cation exchange connector 20 from a low pressure ion source reservoir 22 containing a source of eluent ion. As illustrated, the system is for anion analysis in which the ions to be supplied for the anion analyte are cations, potassium ion as illustrated, or sodium, lithium or other cations. The ion source reservoir may be in the form of a base or salt solution which can be replenished as illustrated in the '701 patent. The charged permselective membrane barrier or connector 20 substantially prevents bulk liquid flow while providing an ion transport bridge to transport the potassium ions into the base generation chamber. Suitable membranes, e.g. ones formed of Nafion®, are illustrated in the '701 patent. The ion source reservoir 22 of the embodiment shown in FIG. 1 also contains an ion reflux column 24 that has a fluid inlet port 24 a and a fluid outlet port 24 b . The ion reflux column 24 is packed with cation exchange resin in a bed 26 and preferably is predominantly in the hydronium form. Outlet 24 b is fitted with a flow-through Pt anode which is in direct physical contact with the cation exchange resin bed 26 . The inlet region of the column is fitted with cation exchange connector 28 that separates resin bed 26 from the potassium electrolyte solution in the ion source reservoir 22 . The charged permselective membrane barrier or connector 28 substantially prevents bulk liquid flow while providing an ion transport bridge to transport the potassium ions from the cation exchange resin bed 26 in the ion reflux column 24 into the ion source reservoir 22 . In the embodiment illustrated in FIG. 1 , electrolysis is performed to provide the reaction illustrated in the '701 patent so that the base, KOH, is generated in base generation chamber 16 . Under the applied electric field, the potassium ions migrate from the ion source reservoir 22 across the ion exchange connector 20 to combine with hydroxide ions generated at the cathode 18 to form a KOH eluent. The concentration of KOH solution formed is proportional to the applied current and inversely proportional to the flow rate of the deionized water carrier stream. Hydrogen gas is generated at cathode 18 which could interfere with analysis of the sample. Thus, it is preferable to use a degassing tubing device 30 typically using a porous membrane adjacent to flow to remove the hydrogen gas from the sample stream, also illustrated in the '701 patent. Sample is injected at sample injector 32 and carried by the eluent from the KOH generation chamber 16 to ion exchange chromatographic separation column 34 . For anion analysis, separation is performed using anion separation medium, typically a packed bed of ion exchange resin in the column. As illustrated in FIG. 1 , the effluent from the anion separation column flows to an electrolytic anion suppressor 36 and a conductivity detector 38 , although other detectors such as UV-Vis, electrochemical, and mass spectrometry detectors may be used. In the embodiment illustrated in FIG. 1 , the electrolytic anion suppressor is operated in the external water mode (i.e., an external source of water is used in the electrolytic generation of regenerant hydronium ions). The electrolytic anion suppressor used in this embodiment can be of the type of the electrolytically-regenerated membrane suppressors as described in U.S. Pat. Nos. 4,999,098, 5,248,426, 5,352,360, and 6,325,976 or other types. The principles of operation of electrolytically-regenerated membrane suppressors are described in details in those patents. As illustrated, suppressor 36 is a flat membrane suppressor which includes a sample stream flow channel 36 a , a regenerant flow channel 36 b , and a permselective ion exchange membrane 36 c separating the two channels. Referring to the embodiment of FIG. 1 , the regenerant water in a container or reservoir 40 is pumped by pump 41 through optional regenerant purification column 42 that is packed with anion exchange resin. This column is used to remove dissolved carbon dioxide and other anionic contaminants such as carbonate in the regenerant water. Column 42 may also contain a zone of cation exchange resin to remove cationic contaminants and a zone of appropriate chromatographic packing material to remove neutral contaminants in the regenerant water. The regenerant water leaving column 42 then flows into regenerant flow channel 36 b of the electrolytic suppressor 36 . The solution flowing out the regenerant flow channel 36 b contains a mixture of KOH solution and stoichiometrical amounts of hydrogen gas and oxygen gas formed through the oxidation and reduction of water at the anode (H 2 O−2e − →2H + +½O 2 ↑) and cathode (2H 2 O+2e − →2OH − +H 2 ↑) during the operation of the anion electrolytic suppressor. This suppressor regenerant effluent mixture is passed through optional catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described in U.S. patent application Ser. No. 11/065,335, filed Feb. 23, 2005, entitled “Ion Chromatography System Using Catalytic Gas Elimination”. The use of column 44 offers the benefits of eliminating hydrogen and oxygen gases and the generation of water for the regenerant solution. The KOH solution leaving column 44 is free of hydrogen and oxygen gas. This solution may then be passed though the low pressure chamber of degas tubing assembly 32 to remove hydrogen gas formed in the electrolytic generation of the KOH eluent in chamber 16 . The mixture of KOH and hydrogen is then directed to the inlet of the ion reflux column 24 . Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 located near the inlet region of column 24 into the potassium ion source reservoir 22 . The amount of potassium ions migrating into the potassium ion source reservoir 22 is equal to the amount of potassium ions migrating out of reservoir 22 into the KOH generation chamber 16 in the electrolytic generation of KOH eluent. Thus, the ion chromatography system illustrated in FIG. 1 utilizes a perpetual process of consuming and recycling of potassium source ions in ion chromatographic process. Perpetual process of consuming and recycling of potassium source ions has been described in U.S. Pat. No. 6,562,628. Since potassium ions are recycled back to the ion source reservoir 22 , the effluent leaving the outlet of ion reflux column 24 contains water and stoichiometric amount of hydrogen gas and oxygen gas. The effluent from column 24 can be then passed through another optional catalytic gas elimination column 46 where hydrogen and oxygen react catalytically to form water. The water leaving column 46 is then recycled back to the water regenerant reservoir 40 . Therefore, the ion chromatography system illustrated in FIG. 1 provides a novel approach to recycle the regenerant water used in the operation of an anion electrolytic suppressor 36 . The regenerant solution recycles through the ion chromatography system out of fluid communication with the sample stream exiting from the detector. FIG. 2 shows another embodiment of the present invention. Like parts in FIGS. 1 and 2 will be designated with like numbers. In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line. Sample is injected in injector 32 and carried by the eluent pumped by pump 14 from a source, not shown, to an ion exchange chromatographic separation column 34 . For anion analysis, separation is performed using anion exchange separation medium. As illustrated, the effluent from column 34 flows to an electrolytic anion suppressor 36 and detector 38 . In the embodiment illustrated in FIG. 2 , electrolytic anion suppressor 36 is operated in the external water mode. The regenerant water is pumped by pump 41 from reservoir 40 through a regenerant purification column 42 used to remove ionic and neutral contaminants in the regenerant water. The regenerant water leaving the regenerant purification column 42 then flows into the regenerant flow channel 36 b of electrolytic suppressor 36 . The solution flowing out the regenerant flow channel 36 b contains a mixture of KOH solution and stoichiometrical amounts of hydrogen gas and oxygen gas formed through the oxidation and reduction of water at the anode (H 2 O−2e − →2H + +½O 2 ↑) and cathode (2H 2 O+2e − →2OH − +H 2 ↑) during the operation of the anion electrolytic suppressor. This suppressor regenerant effluent mixture is passed through optional catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described above for the embodiment shown in FIG. 1 . The KOH solution leaving catalytic gas elimination column 44 is free of hydrogen and oxygen gas and is directed to the inlet of the ion reflux column 24 in the electrolytic regenerant recycle device 50 . Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 into the electrolyte reservoir 22 . In the meantime, water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of device 50 . Hydronium ions migrate into the resin bed 26 to replenish the hydronium ions consumed due to the neutralization reaction with the incoming hydroxide ions. Since potassium ions are removed into the electrolyte reservoir 22 , the ion reflux column effluent contains water and oxygen gas generated at the device anode and is directed to flow through the cathode compartment 16 which is connected to the electrolyte reservoir 22 through an anion exchange connector 20 . Under the applied electrical field, hydroxide ions formed from the reduction of water migrate across the anion exchange connector 20 into the electrolyte reservoir 22 to maintain the solution charge neutrality in the solution reservoir. In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 should be adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream. The effluent leaving the outlet of the cathode compartment 16 of the electrolytic regenerant recycle device 50 contains water and stoichiometric amount of hydrogen gas and oxygen gas. This effluent can be then passed through another catalytic gas elimination column 52 where hydrogen and oxygen react catalytically to form water. The water leaving the catalytic gas elimination column 46 is then recycled back to the water regenerant reservoir 40 . The ion chromatography system illustrated in FIG. 2 provides another approach according to the invention to recycle the regenerant water used in the operation of an anion electrolytic suppressor. In contrast to the embodiment shown in FIG. 1 , the embodiment illustrated in FIG. 2 allows the use of the eluent that is either prepared by conventional means off-line or generated electrolytically on-line. FIG. 3 shows another embodiment of the present invention. In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line. The ion chromatographic process is performed in this embodiment using the similar components described previously for the embodiment shown In FIG. 2 . Like parts with FIGS. 1 and 2 will be illustrated with like numbers. In the embodiment illustrated in FIG. 3 , the electrolytic anion suppressor 36 also is operated in the external water mode. The regenerant water from reservoir 40 is pumped through optional regenerant purification column 42 used to remove ionic and neutral contaminants in the regenerant water. This suppressor regenerant effluent mixture from regenerant channel 36 b is passed through a catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described previously. The KOH solution leaving the catalytic gas elimination column 44 is free of hydrogen and oxygen gas and is directed to the inlet of the ion reflux column 24 in the electrolytic regenerant recycle device 50 . The electrolytic regenerant recycle device in the embodiment shown in FIG. 3 is constructed such that the device cathode 54 is placed directly in the electrolyte reservoir. Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 located near the inlet region of the ion reflux column into the electrolyte reservoir. Water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of ion reflux column. Hydronium ions migrate into the resin bed 26 to replenish the hydronium ions consumed due to the neutralization reaction with the incoming hydroxide ions. In the meantime, hydroxide ions are formed from the reduction of water at cathode 54 to maintain the solution charge neutrality in the electrolyte reservoir 22 . In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 preferably is adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream. In the embodiment shown in FIG. 3 , effluent from ion reflux column 24 contains water and oxygen gas generated at the device anode and is recycled back into the water regenerant reservoir 40 which is fitted with a vent port 40 a to allow the release of oxygen gas into the ambient. In this embodiment, there is a consumption of water due to the oxidation reaction at the anode of the ion reflux column 24 . The amount of water consumed is determined by the amount of current applied to device 50 and is rather minute under the typical ion chromatographic operating conditions. Therefore, the ion chromatography system illustrated in FIG. 3 provides another approach according to the invention to recycle the regenerant water used in the operation of an anion electrolytic suppressor. FIG. 4 illustrates another embodiment of ion chromatography systems in which the suppressor regenerant water is recycled in the operation of the electrolytically-regenerated suppressor operated in the external water mode. Like parts with those of FIGS. 1-3 will be designated with like numbers. In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line. The ion chromatographic process is performed in this embodiment using the similar components described previously. The regenerant solution from reservoir 40 is pumped by pump 41 through a regenerant purification column 42 used to remove anionic and neutral contaminants in the regenerant water. This suppressor regenerant effluent mixture is passed through a catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described previously. The KOH solution leaving the catalytic gas elimination column 44 is free of hydrogen and oxygen gas and directed into the inlet of an electrolytic regenerant recycle device 56 . In the embodiment shown in FIG. 4 , the electrolytic regenerant recycle device may take the form of a column 58 packed with a cation ion exchange resin bed. The resin is suitably contained in the column by porous frits at the column inlet and outlet. The device is fitted with an anode compartment 60 near the outlet region of the cation exchange resin bed and a cathode compartment near the inlet region of the cation exchange resin bed. The anode and cathode compartments have inlet and outlet liquid connecting ports. Electrodes 60 a and 62 a in the anode and cathode compartments, respectively, are preferably separated from the resin bed by cation exchange connectors 60 b and 62 b , respectively, that prevent any significant liquid flow but permit the transport of ions only of the same charge as the charge of exchangeable ions on resin bed. Overall, the construction and operation of this embodiment of electrolytic regenerant recycle device is similar to the continuously regenerated packed bed suppressor described in FIG. 2 of U.S. Pat. No. 6,325,976. The electrolytic regenerant recycle device serves the function of electrolytically suppressing the KOH solution coming from the catalytic gas elimination column 44 . In this embodiment, the amount of current applied to the electrolytic regenerant recycle device should be adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream. In the embodiment shown in FIG. 4 , the detector effluent may be directed to flow through the anode and cathode compartments 60 and 62 of the electrolytic regenerant recycle device as illustrated in U.S. Pat. No. 6,325,976. This flowing liquid stream carries the KOH out of the cathode compartment to waste. The suppressed effluent from the electrolytic regenerant recycle device is water and thus can be recycled back into the regenerant water reservoir. Therefore, the ion chromatography system illustrated in FIG. 4 provides another novel approach to recycling the regenerant water used in the operation of an anion electrolytic suppressor. In another embodiment, not shown, the effluent from cathode chamber 62 , which comprises an KOH solution may be cycled to injector 32 as a source of part or all of the eluent, thereby reducing or eliminating the external KOH source. Such recycle is illustrated in U.S. Pat. No. 6,027,643. The present invention is also applicable to the recycle of acid or base regenerants used in the operation of chemically-regenerated suppressors in ion chromatography systems. FIG. 5 illustrates one embodiment of ion chromatography systems in which sulfuric acid regenerant used in the operation of an anion membrane suppressor is recycled. Like parts with the embodiments of FIGS. 1-4 will be designated with like numbers. In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line. The ion chromatographic process is performed using similar components described previously, except that a chemically-regenerated membrane system suitably of the type described in FIG. 1 of U.S. Pat. No. 4,999,098, is used. In the embodiment illustrated in FIG. 5 herein, the sulfuric acid regenerant is delivered by a pump 41 from the regenerant reservoir 40 into the suppressor regeneration flow channel 36 b to supply hydronium ions used in the suppression of the KOH eluent. The effluent from regeneration flow channel 36 b contains a mixture of potassium sulfate and sulfuric acid. The used regenerant liquid stream is then directed to the inlet 24 a of the ion reflux column 24 in the electrolytic regenerant recycle device 50 . The construction and operation of the electrolytic regenerant recycle device of the embodiment illustrated in FIG. 5 is similar to the one used in the embodiment illustrated in FIG. 3 . Under the applied electrical field, potassium ions in the regenerant stream migrate across the cation exchange connector 28 located near the inlet region of the ion reflux column 24 into the electrolyte reservoir 22 . Water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of ion reflux column. Hydronium ions combine with the incoming sulfate ions to form sulfuric acid. In the meantime, hydroxide ions formed from the reduction of water at the cathode 54 combine with potassium ions to maintain the solution charge neutrality in the electrolyte reservoir. In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 should be adjusted to a level that is sufficient to ensure the complete removal of potassium ions in the regenerant stream to convert potassium sulfate to sulfuric acid. In the embodiment shown in FIG. 5 , the ion reflux column 24 effluent contains the sulfuric acid regenerant and oxygen gas generated at the device anode and is directed to recycled back to the sulfuric acid regenerant reservoir 40 which is fitted with a vent port (not shown) to allow the release of oxygen gas into the ambient. In this embodiment, there is a consumption of water due to the oxidation reaction at the anode of the electrolytic regenerant recycle device 50 . The amount of water consumed is determined by the amount of current applied to the electrolytic regenerant recycle device 50 and rather minute under the typical ion chromatographic operating conditions. Therefore, the ion chromatography system illustrated in FIG. 5 provides a novel approach to recycle the sulfuric acid regenerant used in the operation of the chemically-regenerated suppressor in an ion chromatography system. FIG. 6 illustrates another preferred embodiment of ion chromatography systems in which the sulfuric acid regenerant used in the operation of an anion membrane suppressor is recycled. In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line. The ion chromatographic process is performed using similar components described previously, except that a chemically-regenerated membrane suppressor system, suitably of the type described in FIG. 1 of U.S. Pat. No. 4,999,098, is used. In the embodiment illustrated in FIG. 6 , the sulfuric acid regenerant is delivered by a pump 41 from the regenerant reservoir 40 into the suppressor regenerant channel 36 b to supply hydronium ions used in the suppression of ion chromatographic eluent (KOH). The effluent from channel 36 b contains a mixture of potassium sulfate and sulfuric acid. The used regenerant liquid stream is then directed to the inlet of the ion reflux column in the electrolytic regenerant recycle device. The construction of the electrolytic regenerant recycle device 56 of the embodiment illustrated in FIG. 6 is similar to the one used in the embodiment illustrated in FIG. 4 . Device 56 serves the function of converting potassium sulfate in the suppressor effluent to sulfuric acid. The operation of device 56 in this embodiment is described below. Under the applied electrical field, potassium ions in the incoming regenerant solution migrate across the cation exchange connector 62 b located near the inlet region of device 56 into the cathode compartment 62 and combine with hydroxide ions generated at the cathode 62 a to form a potassium hydroxide solution. In the meantime, water is oxidized to form hydronium ions at the anode compartment 60 located near the outlet of the electrolytic regenerant recycle device 56 . Hydronium ions migrate across the cation exchange connector 60 to the resin bed 26 of device 56 and combine with sulfate to form sulfuric acid. In this embodiment, the amount of current applied to device 56 should be adjusted to a level that is sufficient to ensure the complete removal of potassium ions in the regenerant stream to convert potassium sulfate to sulfuric acid. The sulfuric acid regenerant solution is then recycled back to the regenerant reservoir 40 . The ion chromatography system illustrated in FIG. 6 provides another approach according to the invention to recycle the sulfuric acid regenerant used in the operation of the chemically-regenerated suppressor in an ion chromatography system. It should be pointed out that, by using appropriate anion exchange materials, the various embodiments described above can also be implemented in forms that are suitable for suppressing acid eluents for determination of cationic analytes. The following examples illustrate the present invention in ion chromatographic separation of ionic analytes EXAMPLE 1 Ion Chromatography System Using Electrolytic Eluent Generation with Recycled Source Ions and Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an ion chromatography (IC) system using electrolytic eluent generation with recycled source ions and electrolytic suppression with recycled regenerant water in the separation of common anions. The IC system used in the experiment was constructed according to the scheme shown in FIG. 1 . A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min. To generate and recycle a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of the KOH eluent generation and recycle module. The KOH eluent generation and recycle module was prepared by modifying a Dionex EGC-KOH cartridge (P/N 058900) through the addition of an ion reflux column placed in the potassium ion electrolyte reservoir which was filled with 1.0 liter of 0.5 M KOH. The ion reflux column was prepared by using a cylindrical PEEK housing that has cylindrical internal cavity of 9-mm ID×150 mm length which was packed with cation exchange resin in the hydronium form (8% cross-linked and 20-μm sulfonated styrene divinylbenzene resin beads, Dionex Corporation). The outlet of the column was fitted a flow-through Pt anode which was in direct physical contact with the cation exchange resin bed. The inlet region of the column was fitted with cation exchange connector that separated the resin bed from the potassium electrolyte solution in the ion source reservoir. A Dionex EG40 eluent generator control module was used to supply DC currents to the KOH eluent generation and recycle module. The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process. A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples. The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter. A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used. Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing. In this example, an electrolytic capillary suppressor was prepared as described below. The capillary anion suppressor consisted of three PEEK chambers. The eluent chamber contained a cation exchange capillary tubing embedded tightly inside a bed (8 mm ID×10 mm in length) of cation exchange resin (8% cross-linked and 20-μm sulfonated styrene divinylbenzene resin beads, Dionex Corporation). Provisions were made provide separate fluid connections to the cation exchange capillary tubing in the resin bed. A 15-cm length of a proprietary grafted and sulfonated TFE capillary tubing of 0.004-inch ID×0.010-inch OD (Dionex Corporation) was used in the construction of the electrolytic capillary anion suppressor. The eluent chamber was physically separated from the cathodic regenerant chamber and anodic regenerant chamber using proprietary grafted and sulfonated TFE cation exchange ion exchange membranes (Dionex Corporation). The cathode chamber contained a perforated Pt cathode and the anode chamber contains a perforated Pt anode. Both electrode chambers had two liquid connecting ports (inlet and outlet). In this example, the suppressed eluent from the outlet of the conductivity cell was routed to waste. A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min. The regenerant water was routed through the resin bed in eluent chamber, then to the anodic regenerant chamber and the cathodic regenerant chamber of the electrolytic anion suppressor. A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor. The catalytic gas elimination columns where hydrogen and oxygen gases react catalytically to form water were prepared by packing small strips of Pt foil in PEEK columns of 4-mm ID×50-mm length. One catalytic gas elimination column was placed downstream from the outlet of cathode chamber of the electrolytic suppressor. The other catalytic gas elimination column was placed downstream from the outlet of the ion reflux column. In one set of experiments, the KOH eluent generation and recycle module was programmed to generate and recycle 35 mM KOH at 10 μL/min by applying 0.563 mA of DC current to the device. The regenerant reservoir was initially filled with 100 mL of deionized water. The regenerant flow rate was 0.10 mL/min. The system was used to perform separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) continuously for more than 240 hours. No noticeable loss of regenerant water in the reservoir was observed over the period of 240 hours. If the regenerant water was not recycled, the consumption of regenerant water would have been 1440 mL. FIG. 7 shows the separation of five common anions obtained using the system shown in FIG. 1 by operating the electrolytic suppressor in the external water mode either with fresh regenerant water or with the recycled regenerant water. FIGS. 8 and 9 show the analyte retention time and peak area response reproducibility data obtained during the experiments. The results show that essentially identical separations were achieved under the conditions with or without recycling the regenerant water. For example, the average sulfate retention time was 6.25 minutes with a relative standard deviation (RDS) of 0.17 percent (n=24) and sulfate peak area response was 0.5822 μS·minute with a RDS of 0.91 percent (n=24) using over a period of 24 hours when the electrolytic suppressor was operated in the external water mode with fresh regenerant water. When the electrolytic suppressor was operated in the external water mode with recycled regenerant water, the average sulfate retention time was 6.23 minutes with a RDS of 0.36 percent (n=100) and sulfate peak area response was 0.5850 μS·minute with a RDS of 0.29 percent (n=100) using over a period of 100 hours. Therefore, the above results demonstrate that the ion chromatography system using electrolytic eluent generation with recycled source ions and electrolytic suppression with recycled regenerant water can be used to provide reliable determination of target anionic analytes. EXAMPLE 2 Ion Chromatography System Using Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an IC system using electrolytic suppression with recycled regenerant water in the separation of common anions. The IC system used in the experiment was constructed according to the embodiment shown in FIG. 3 . A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min. To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH eluent generator cartridge (P/N 058900). The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process. A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples. The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter. The electrolytic suppressor described in Example 1 was used. The suppressed eluent from the conductivity cell was routed to waste. A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min. A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor. A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used. A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing. The electrolytic regenerant recycle device was constructed by immersing an ion reflux column in a 100-mL reservoir filled with 0.5 M KOH solution. A Pt cathode was placed in the electrolyte reservoir of the electrolytic regenerant recycle device. The ion reflux column was prepared by using a cylindrical PEEK housing that has cylindrical internal cavity of 9-mm ID×150 mm length which was packed with cation exchange resin in the hydronium form. The outlet of the column was fitted a flow-through Pt anode which was in direct physical contact with the cation exchange resin bed. The inlet region of the column was fitted with cation exchange connector that separated the resin bed from the potassium electrolyte solution in the ion source reservoir. A Dionex SC20 control module was used to supply 2.0 mA of DC current to the electrolytic regenerant recycle device. One catalytic gas elimination column (4-mm ID×50-mm length) prepared by packing small strips of Pt foil was placed downstream from the outlet of cathode chamber of the electrolytic suppressor to allow the reaction of hydrogen and oxygen catalytically to form water. In one set of experiments, the regenerant reservoir was initially filled with 100 mL of deionized water. The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for 45 hours. No noticeable loss of regenerant water was observed over the period of 45 hours. If the regenerant water was not recycled, the consumption of water would have been 270 mL. The results show that identical separations were achieved under the conditions with or without recycling the regenerant water. During the period of 45 hours, the percent RDS of analyte retention time were 0.34% for chloride and 0.58% for sulfate (n=45); the percent RDS of analyte peak height response were 0.70% for fluoride and 0.69% for sulfate (n=45). Therefore, the above results demonstrate that the ion chromatography system with the recycled regenerant water shown in FIG. 3 can be used to provide reliable determination of target anionic analytes. EXAMPLE 3 Ion Chromatography System Using Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an IC system using electrolytic suppression with recycled regenerant water in the separation of common anions. The IC system used in the experiment was constructed according to the embodiment shown in FIG. 4 . A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min. To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH eluent generator cartridge (P/N 058900). The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process. A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples. The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter. The electrolytic suppressor described in Example 1 was used. The suppressed eluent from the conductivity cell was routed to the anode and cathode compartments of the electrolytic regenerant device before going to waste. A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min. A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor. A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used. A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing. In this example, a Dionex anion Atlas electrolytic suppressor (P/N 056116) was used as the electrolytic regenerant recycle device. A Dionex SC20 module was used to supply 5 mA of DC current to the electrolytic regenerant recycle device. One catalytic gas elimination column (4-mm ID×50-mm length) prepared by packing small strips of Pt foil was placed downstream from the outlet of cathode chamber of the electrolytic suppressor to allow the reaction of hydrogen and oxygen catalytically to form water. The effluent from the outlet of the catalytic gas elimination column was directed to the ELUENT IN port of the anion Atlas electrolytic suppressor. The effluent from the ELUENT OUT port of the anion Atlas electrolytic suppressor was recycled back to the regenerant reservoir. In one set of experiments, the regenerant reservoir was initially filled with 100 mL of deionized water. The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for 95 hours. No noticeable loss of regenerant water was observed over the period of 95 hours. If the regenerant water was not recycled, the consumption of water would have been 570 mL. During the period of 95 hours, the percent RDS of analyte retention time were 0.11% for chloride and 0.17% for sulfate (n=95); the percent RDS of analyte peak area response were 0.71% for chloride and 0.74% for sulfate (n=95). Therefore, the above results demonstrate that the ion chromatography system with the recycled regenerant water shown in FIG. 4 can be used to provide reliable determination of target anionic analytes. EXAMPLE 4 Ion Chromatography System Using Chemically-Regenerated Suppressor with Recycled Sulfuric Acid Regenerant This example demonstrates the use of an IC system using chemically-regenerated suppressor with recycled sulfuric acid regenerant in the separation of common anions. The IC system used in the experiment was constructed according to the embodiment shown in FIG. 6 . A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min. To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH cartridge (P/N 058900). The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process. A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples. The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter. In this example, the anion suppressor described in Example 1 was used in the chemical regeneration mode using sulfuric acid as the regenerant. A Dionex GS 50 pump was used to deliver the stream of 20 mM sulfuric acid to the resin bed in the eluent chamber of the suppressor at 0.10 mL/min. A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used. A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing. In this example, a Dionex anion Atlas electrolytic suppressor (P/N 056116) was used as the electrolytic regenerant recycle device. A Dionex RFC-30 control module was used to supply 5 mA of DC current to the electrolytic regenerant recycle device. The effluent from the outlet of anion suppressor was directed to the ELUENT IN port of the anion Atlas electrolytic suppressor. The effluent from the ELUENT OUT port of the anion Atlas electrolytic suppressor was recycled back to the regenerant reservoir. In one set of experiments, the regenerant reservoir was initially filled with 125 mL of 20 mM sulfuric acid. The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for more than 170 hours. No noticeable loss of sulfuric acid regenerant was observed over the period of 170 hours. If the sulfuric acid regenerant was not recycled, the consumption of 20 mM sulfuric acid would have been 1020 mL. During the period of 170 hours, the percent RDS of analyte retention time were 0.10% for chloride and 0.17% for sulfate (n=170); the percent RDS of analyte peak area response were 1.18% for chloride and 1.72% for sulfate (n=170). Therefore, the above results demonstrate that the ion chromatography system with the recycled sulfuric acid regenerant shown in FIG. 6 can be used to provide reliable determination of target anionic analytes.
A suppressed ion chromatographic apparatus using a regenerant recycle loop, comprising (a) an ion separation device, (b) a membrane suppressor, (c) a detector, (d) a container for regenerant solution, (e) a first conduit between the ion separation device and the suppressor, (f) a second conduit between the regenerant solution container and the suppressor, (g) a third conduit between the suppressor and the regenerant solution container, and (h) a regenerant solution recycle loop out of fluid communication with the detector outlet.
Identify the most important claim in the given context and summarize it
[ "CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional application of U.S. application Ser.", "No. 11/229,022, filed on Sep. 16, 2005, now U.S. Pat. No. 7,473,354.", "BACKGROUND OF THE INVENTION The present invention relates to ion chromatography systems for determination of both anionic and cationic analytes.", "Ion chromatography is a widely used analytical technique for the determination of anionic and cationic analytes in various sample matrices.", "Ion chromatography, also called suppressed ion chromatography, includes a chromatographic separation stage using an eluent containing an electrolyte, an eluent suppression stage, followed by the detection stage, typically using an electrical conductivity detector.", "In the chromatographic separation stage, ionic analytes of an injected sample are eluted through a separation column and separated from each other using an electrolyte as the eluent.", "In the suppression stage, an eluent suppression device, or suppressor, is the critical system component used to convert the eluent into a weakly conducting form and enhance the conductance of target analytes.", "This technique has been described in detail in U.S. Pat. Nos. 3,897,213, 3,920,397, 3,925,019, and 3,926,559.", "Even though ion chromatography today comprises a number of separation and detection modes, ion chromatography with suppressed conductivity detection remains the most widely practiced form of the technique.", "The original suppressors were columns packed with ion-exchange resins in appropriate ionic forms.", "Those packed-bed suppressors had a relatively large dead volume and required frequent off-line chemical regeneration.", "To overcome this problem, suppressors based on ion-exchange fibers and membranes were developed.", "Over the years, several designs of electrolytically-regenerated membrane suppressors as described in U.S. Pat. Nos. 4,999,098, 5,248,426, 5,352,360, and 6,325,976 have been also developed to overcome the limitations associated with the chemically-regenerated membrane suppressors.", "The electrolytic suppressors offer several advantages in ion chromatography.", "They provide continuous and simultaneous suppression of eluents, regeneration of the suppression bed, and sufficient suppression capacity for all common IC applications.", "They are easy to operate because either the suppressed eluent or water is used to create regenerant ions electrolytically, and there is no need to prepare regenerant solutions off-line.", "They are compatible with gradient separations.", "They have very low suppression zone volume, which makes it possible to achieve separations with very high chromatographic efficiency.", "In the operation of electrolytically-regenerated membrane suppressors, it is sometimes preferred to operate the electrolytic membrane suppressors in the external water mode because the type of detector used is not amenable to the recycle mode of operation or because lower suppressed background noise achievable in the external water mode of operation is desirable.", "The external water regenerant is typically operated at flow rates that are 2 to 10 times higher than the eluent flow rate and thus typically consume a significant amount of water regenerant.", "For example, a total of 2628 liters of water is required if an ion chromatography system is operated continuously at a separation flow rate of 1.0 mL/min and the water regenerant is operated at 5 mL/min and 24 hours per day for 365 day per year.", "When a constant supply of large amounts of high purity water from an external source is required for continuous operation, the IC system operators face the waste disposal and other logistical challenges to system operation.", "Even though the use of chemically-regenerated membrane suppressors have decreased somewhat in recent years, the membrane suppressors offer the benefits of long lifetime, low noise, and better compatibility with applications where organic solvents are used as in the eluents.", "In the operation of chemically-regenerated membrane suppressors, an external source of either acid or base regenerant solution is required to generate the suppressor continuously.", "The external acid or base regenerant is typically operated at flow rates that are 2 to 10 times higher than the eluent flow rate and thus typically consume a significant amount of regenerants.", "The consistent preparation of such large amount of the regenerant as well as the disposal of the used regenerant can pose serious logistical challenges to the system operators in terms of costs and labor, especially in cases where unattended or less frequently attended operations are required.", "There is a need to minimize waste disposal, and reduce operating costs of the regenerant solutions used in the operation of both the chemically-regenerated and electrolytically-regenerated suppressors.", "BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-6 are schematic representations of different suppressed ion chromatography systems with recycled eluents according to the present invention.", "FIG. 7 is a chromatogram illustrating the present invention.", "FIGS. 8 and 9 illustrate reproducibility data using the present invention.", "SUMMARY OF THE INVENTION In one embodiment, the invention is a suppressed ion chromatographic apparatus using a regenerant recycle loop, comprising (a) an ion separation device including ion separation medium with exchangeable ions of one charge, positive or negative, (b) a membrane suppressor comprising a sample stream flow channel, having an inlet and an outlet, a regenerant flow channel, having an inlet and an outlet, and an ion exchange membrane separating the sample stream flow channel and regenerant flow channel, (c) a detector having an inlet and an outlet, the detector inlet being in fluid communication with the sample stream flow channel outlet, (d) a container for regenerant solution, (e) a first conduit providing fluid communication between the ion separation device and the sample stream flow channel inlet, (f) a second conduit providing fluid communication between the regenerant solution container and the regenerant flow channel, (g) a third conduit providing fluid communication between the regenerant channel and the regenerant solution container, and (h) a regenerant solution recycle loop comprising the second and third conduits, the recycle loop being out of fluid communication with the detector outlet.", "In another embodiment, the invention is a method for suppressed ion chromatography using a regenerant solution recycle loop, comprising (a) separating sample ions of one charge, positive or negative, in a liquid sample stream including eluent by flowing the same through ion separation medium in an ion separation device, (b) suppressing the eluent by flowing the effluent from the ion separation medium through a sample stream flow channel of a membrane suppressor comprising a sample stream flow channel, having an inlet and an outlet, a regenerant flow channel, having an inlet and an outlet, and an ion exchange membrane separating the sample stream flow channel and regenerant flow channel, (c) detecting the separated sample ions by flowing the effluent from the sample stream flow channel through a detector, (d) flowing a regenerant solution through the regenerant flow channel, (e) providing a regenerant solution reservoir, and (f) flowing the regenerant solution between the regenerant solution reservoir and the regenerant flow channel in a recycle loop independent of liquid flow through the detector.", "DETAILED DESCRIPTION OF THE INVENTION The present invention relates to various modes of recycling either (1) the regenerants such as water used in the operation of the electrolytically-regenerated suppressors when they are operated in the external water mode, or (2) acid or base regenerants used in the operation of chemically-regenerated suppressors.", "Referring to FIG. 1 , the invention will first be described in the recycled water mode used in the operation of the electrolytically-regenerated suppressors when they are operated in the external water mode.", "FIG. 1 illustrates the basic components of one of the preferred embodiments of ion chromatography system using recycled suppressor regenerant water.", "In this embodiment, an eluent generator 10 of the type illustrated in FIG. 1 of U.S. Pat. No. 6,682,701 is used with some modification as described below.", "Other eluent generators such as illustrated in the '701 patent can be used in combination with the ion chromatography system of the present invention.", "The principles of operation of the electrolytic eluent generator are fully described in U.S. Pat. No. 6,682,701.", "Other electrolytic eluent generators may be used such as ones which generate a carbonate salt such as potassium carbonate illustrated in PCT Application WO/2004/024302.", "In this instance, the ion chromatography system downstream from the eluent generator also is as illustrated in FIG. 1 .", "Other eluent generators can be used, e.g. as illustrated in U.S. Pat. Nos. 5,045,204 or 6,562,628.", "Although the eluent generators are illustrated for anion analysis and the generation of cations such as potassium ions, for cation analysis, the same system may be used for generating MSA or other anions for an acid eluent by appropriate reversal of the polarity of the membrane ion exchange resin and electrodes such as illustrated in U.S. Pat. No. 6,682,701.", "Referring specifically to the embodiment of FIG. 1 , illustrated for the analyses of anions, deionized water 12 from a source, not shown, is pumped under pressure supplied by pump 14 , through the high pressure base generation chamber 16 of electrolytic generator 10 .", "As illustrated, chamber 16 includes a cathode 18 in communication with a cation exchange bed.", "The high pressure base generation chamber is separated by a cation exchange connector 20 from a low pressure ion source reservoir 22 containing a source of eluent ion.", "As illustrated, the system is for anion analysis in which the ions to be supplied for the anion analyte are cations, potassium ion as illustrated, or sodium, lithium or other cations.", "The ion source reservoir may be in the form of a base or salt solution which can be replenished as illustrated in the '701 patent.", "The charged permselective membrane barrier or connector 20 substantially prevents bulk liquid flow while providing an ion transport bridge to transport the potassium ions into the base generation chamber.", "Suitable membranes, e.g. ones formed of Nafion®, are illustrated in the '701 patent.", "The ion source reservoir 22 of the embodiment shown in FIG. 1 also contains an ion reflux column 24 that has a fluid inlet port 24 a and a fluid outlet port 24 b .", "The ion reflux column 24 is packed with cation exchange resin in a bed 26 and preferably is predominantly in the hydronium form.", "Outlet 24 b is fitted with a flow-through Pt anode which is in direct physical contact with the cation exchange resin bed 26 .", "The inlet region of the column is fitted with cation exchange connector 28 that separates resin bed 26 from the potassium electrolyte solution in the ion source reservoir 22 .", "The charged permselective membrane barrier or connector 28 substantially prevents bulk liquid flow while providing an ion transport bridge to transport the potassium ions from the cation exchange resin bed 26 in the ion reflux column 24 into the ion source reservoir 22 .", "In the embodiment illustrated in FIG. 1 , electrolysis is performed to provide the reaction illustrated in the '701 patent so that the base, KOH, is generated in base generation chamber 16 .", "Under the applied electric field, the potassium ions migrate from the ion source reservoir 22 across the ion exchange connector 20 to combine with hydroxide ions generated at the cathode 18 to form a KOH eluent.", "The concentration of KOH solution formed is proportional to the applied current and inversely proportional to the flow rate of the deionized water carrier stream.", "Hydrogen gas is generated at cathode 18 which could interfere with analysis of the sample.", "Thus, it is preferable to use a degassing tubing device 30 typically using a porous membrane adjacent to flow to remove the hydrogen gas from the sample stream, also illustrated in the '701 patent.", "Sample is injected at sample injector 32 and carried by the eluent from the KOH generation chamber 16 to ion exchange chromatographic separation column 34 .", "For anion analysis, separation is performed using anion separation medium, typically a packed bed of ion exchange resin in the column.", "As illustrated in FIG. 1 , the effluent from the anion separation column flows to an electrolytic anion suppressor 36 and a conductivity detector 38 , although other detectors such as UV-Vis, electrochemical, and mass spectrometry detectors may be used.", "In the embodiment illustrated in FIG. 1 , the electrolytic anion suppressor is operated in the external water mode (i.e., an external source of water is used in the electrolytic generation of regenerant hydronium ions).", "The electrolytic anion suppressor used in this embodiment can be of the type of the electrolytically-regenerated membrane suppressors as described in U.S. Pat. Nos. 4,999,098, 5,248,426, 5,352,360, and 6,325,976 or other types.", "The principles of operation of electrolytically-regenerated membrane suppressors are described in details in those patents.", "As illustrated, suppressor 36 is a flat membrane suppressor which includes a sample stream flow channel 36 a , a regenerant flow channel 36 b , and a permselective ion exchange membrane 36 c separating the two channels.", "Referring to the embodiment of FIG. 1 , the regenerant water in a container or reservoir 40 is pumped by pump 41 through optional regenerant purification column 42 that is packed with anion exchange resin.", "This column is used to remove dissolved carbon dioxide and other anionic contaminants such as carbonate in the regenerant water.", "Column 42 may also contain a zone of cation exchange resin to remove cationic contaminants and a zone of appropriate chromatographic packing material to remove neutral contaminants in the regenerant water.", "The regenerant water leaving column 42 then flows into regenerant flow channel 36 b of the electrolytic suppressor 36 .", "The solution flowing out the regenerant flow channel 36 b contains a mixture of KOH solution and stoichiometrical amounts of hydrogen gas and oxygen gas formed through the oxidation and reduction of water at the anode (H 2 O−2e − →2H + +½O 2 ↑) and cathode (2H 2 O+2e − →2OH − +H 2 ↑) during the operation of the anion electrolytic suppressor.", "This suppressor regenerant effluent mixture is passed through optional catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described in U.S. patent application Ser.", "No. 11/065,335, filed Feb. 23, 2005, entitled “Ion Chromatography System Using Catalytic Gas Elimination.”", "The use of column 44 offers the benefits of eliminating hydrogen and oxygen gases and the generation of water for the regenerant solution.", "The KOH solution leaving column 44 is free of hydrogen and oxygen gas.", "This solution may then be passed though the low pressure chamber of degas tubing assembly 32 to remove hydrogen gas formed in the electrolytic generation of the KOH eluent in chamber 16 .", "The mixture of KOH and hydrogen is then directed to the inlet of the ion reflux column 24 .", "Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 located near the inlet region of column 24 into the potassium ion source reservoir 22 .", "The amount of potassium ions migrating into the potassium ion source reservoir 22 is equal to the amount of potassium ions migrating out of reservoir 22 into the KOH generation chamber 16 in the electrolytic generation of KOH eluent.", "Thus, the ion chromatography system illustrated in FIG. 1 utilizes a perpetual process of consuming and recycling of potassium source ions in ion chromatographic process.", "Perpetual process of consuming and recycling of potassium source ions has been described in U.S. Pat. No. 6,562,628.", "Since potassium ions are recycled back to the ion source reservoir 22 , the effluent leaving the outlet of ion reflux column 24 contains water and stoichiometric amount of hydrogen gas and oxygen gas.", "The effluent from column 24 can be then passed through another optional catalytic gas elimination column 46 where hydrogen and oxygen react catalytically to form water.", "The water leaving column 46 is then recycled back to the water regenerant reservoir 40 .", "Therefore, the ion chromatography system illustrated in FIG. 1 provides a novel approach to recycle the regenerant water used in the operation of an anion electrolytic suppressor 36 .", "The regenerant solution recycles through the ion chromatography system out of fluid communication with the sample stream exiting from the detector.", "FIG. 2 shows another embodiment of the present invention.", "Like parts in FIGS. 1 and 2 will be designated with like numbers.", "In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line.", "Sample is injected in injector 32 and carried by the eluent pumped by pump 14 from a source, not shown, to an ion exchange chromatographic separation column 34 .", "For anion analysis, separation is performed using anion exchange separation medium.", "As illustrated, the effluent from column 34 flows to an electrolytic anion suppressor 36 and detector 38 .", "In the embodiment illustrated in FIG. 2 , electrolytic anion suppressor 36 is operated in the external water mode.", "The regenerant water is pumped by pump 41 from reservoir 40 through a regenerant purification column 42 used to remove ionic and neutral contaminants in the regenerant water.", "The regenerant water leaving the regenerant purification column 42 then flows into the regenerant flow channel 36 b of electrolytic suppressor 36 .", "The solution flowing out the regenerant flow channel 36 b contains a mixture of KOH solution and stoichiometrical amounts of hydrogen gas and oxygen gas formed through the oxidation and reduction of water at the anode (H 2 O−2e − →2H + +½O 2 ↑) and cathode (2H 2 O+2e − →2OH − +H 2 ↑) during the operation of the anion electrolytic suppressor.", "This suppressor regenerant effluent mixture is passed through optional catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described above for the embodiment shown in FIG. 1 .", "The KOH solution leaving catalytic gas elimination column 44 is free of hydrogen and oxygen gas and is directed to the inlet of the ion reflux column 24 in the electrolytic regenerant recycle device 50 .", "Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 into the electrolyte reservoir 22 .", "In the meantime, water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of device 50 .", "Hydronium ions migrate into the resin bed 26 to replenish the hydronium ions consumed due to the neutralization reaction with the incoming hydroxide ions.", "Since potassium ions are removed into the electrolyte reservoir 22 , the ion reflux column effluent contains water and oxygen gas generated at the device anode and is directed to flow through the cathode compartment 16 which is connected to the electrolyte reservoir 22 through an anion exchange connector 20 .", "Under the applied electrical field, hydroxide ions formed from the reduction of water migrate across the anion exchange connector 20 into the electrolyte reservoir 22 to maintain the solution charge neutrality in the solution reservoir.", "In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 should be adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream.", "The effluent leaving the outlet of the cathode compartment 16 of the electrolytic regenerant recycle device 50 contains water and stoichiometric amount of hydrogen gas and oxygen gas.", "This effluent can be then passed through another catalytic gas elimination column 52 where hydrogen and oxygen react catalytically to form water.", "The water leaving the catalytic gas elimination column 46 is then recycled back to the water regenerant reservoir 40 .", "The ion chromatography system illustrated in FIG. 2 provides another approach according to the invention to recycle the regenerant water used in the operation of an anion electrolytic suppressor.", "In contrast to the embodiment shown in FIG. 1 , the embodiment illustrated in FIG. 2 allows the use of the eluent that is either prepared by conventional means off-line or generated electrolytically on-line.", "FIG. 3 shows another embodiment of the present invention.", "In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line.", "The ion chromatographic process is performed in this embodiment using the similar components described previously for the embodiment shown In FIG. 2 .", "Like parts with FIGS. 1 and 2 will be illustrated with like numbers.", "In the embodiment illustrated in FIG. 3 , the electrolytic anion suppressor 36 also is operated in the external water mode.", "The regenerant water from reservoir 40 is pumped through optional regenerant purification column 42 used to remove ionic and neutral contaminants in the regenerant water.", "This suppressor regenerant effluent mixture from regenerant channel 36 b is passed through a catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described previously.", "The KOH solution leaving the catalytic gas elimination column 44 is free of hydrogen and oxygen gas and is directed to the inlet of the ion reflux column 24 in the electrolytic regenerant recycle device 50 .", "The electrolytic regenerant recycle device in the embodiment shown in FIG. 3 is constructed such that the device cathode 54 is placed directly in the electrolyte reservoir.", "Under the applied electrical field, potassium ions migrate across the cation exchange connector 28 located near the inlet region of the ion reflux column into the electrolyte reservoir.", "Water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of ion reflux column.", "Hydronium ions migrate into the resin bed 26 to replenish the hydronium ions consumed due to the neutralization reaction with the incoming hydroxide ions.", "In the meantime, hydroxide ions are formed from the reduction of water at cathode 54 to maintain the solution charge neutrality in the electrolyte reservoir 22 .", "In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 preferably is adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream.", "In the embodiment shown in FIG. 3 , effluent from ion reflux column 24 contains water and oxygen gas generated at the device anode and is recycled back into the water regenerant reservoir 40 which is fitted with a vent port 40 a to allow the release of oxygen gas into the ambient.", "In this embodiment, there is a consumption of water due to the oxidation reaction at the anode of the ion reflux column 24 .", "The amount of water consumed is determined by the amount of current applied to device 50 and is rather minute under the typical ion chromatographic operating conditions.", "Therefore, the ion chromatography system illustrated in FIG. 3 provides another approach according to the invention to recycle the regenerant water used in the operation of an anion electrolytic suppressor.", "FIG. 4 illustrates another embodiment of ion chromatography systems in which the suppressor regenerant water is recycled in the operation of the electrolytically-regenerated suppressor operated in the external water mode.", "Like parts with those of FIGS. 1-3 will be designated with like numbers.", "In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line.", "The ion chromatographic process is performed in this embodiment using the similar components described previously.", "The regenerant solution from reservoir 40 is pumped by pump 41 through a regenerant purification column 42 used to remove anionic and neutral contaminants in the regenerant water.", "This suppressor regenerant effluent mixture is passed through a catalytic gas elimination column 44 where hydrogen and oxygen react catalytically to form water as described previously.", "The KOH solution leaving the catalytic gas elimination column 44 is free of hydrogen and oxygen gas and directed into the inlet of an electrolytic regenerant recycle device 56 .", "In the embodiment shown in FIG. 4 , the electrolytic regenerant recycle device may take the form of a column 58 packed with a cation ion exchange resin bed.", "The resin is suitably contained in the column by porous frits at the column inlet and outlet.", "The device is fitted with an anode compartment 60 near the outlet region of the cation exchange resin bed and a cathode compartment near the inlet region of the cation exchange resin bed.", "The anode and cathode compartments have inlet and outlet liquid connecting ports.", "Electrodes 60 a and 62 a in the anode and cathode compartments, respectively, are preferably separated from the resin bed by cation exchange connectors 60 b and 62 b , respectively, that prevent any significant liquid flow but permit the transport of ions only of the same charge as the charge of exchangeable ions on resin bed.", "Overall, the construction and operation of this embodiment of electrolytic regenerant recycle device is similar to the continuously regenerated packed bed suppressor described in FIG. 2 of U.S. Pat. No. 6,325,976.", "The electrolytic regenerant recycle device serves the function of electrolytically suppressing the KOH solution coming from the catalytic gas elimination column 44 .", "In this embodiment, the amount of current applied to the electrolytic regenerant recycle device should be adjusted to a level that is sufficient to ensure the complete removal of KOH in the regenerant stream.", "In the embodiment shown in FIG. 4 , the detector effluent may be directed to flow through the anode and cathode compartments 60 and 62 of the electrolytic regenerant recycle device as illustrated in U.S. Pat. No. 6,325,976.", "This flowing liquid stream carries the KOH out of the cathode compartment to waste.", "The suppressed effluent from the electrolytic regenerant recycle device is water and thus can be recycled back into the regenerant water reservoir.", "Therefore, the ion chromatography system illustrated in FIG. 4 provides another novel approach to recycling the regenerant water used in the operation of an anion electrolytic suppressor.", "In another embodiment, not shown, the effluent from cathode chamber 62 , which comprises an KOH solution may be cycled to injector 32 as a source of part or all of the eluent, thereby reducing or eliminating the external KOH source.", "Such recycle is illustrated in U.S. Pat. No. 6,027,643.", "The present invention is also applicable to the recycle of acid or base regenerants used in the operation of chemically-regenerated suppressors in ion chromatography systems.", "FIG. 5 illustrates one embodiment of ion chromatography systems in which sulfuric acid regenerant used in the operation of an anion membrane suppressor is recycled.", "Like parts with the embodiments of FIGS. 1-4 will be designated with like numbers.", "In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line.", "The ion chromatographic process is performed using similar components described previously, except that a chemically-regenerated membrane system suitably of the type described in FIG. 1 of U.S. Pat. No. 4,999,098, is used.", "In the embodiment illustrated in FIG. 5 herein, the sulfuric acid regenerant is delivered by a pump 41 from the regenerant reservoir 40 into the suppressor regeneration flow channel 36 b to supply hydronium ions used in the suppression of the KOH eluent.", "The effluent from regeneration flow channel 36 b contains a mixture of potassium sulfate and sulfuric acid.", "The used regenerant liquid stream is then directed to the inlet 24 a of the ion reflux column 24 in the electrolytic regenerant recycle device 50 .", "The construction and operation of the electrolytic regenerant recycle device of the embodiment illustrated in FIG. 5 is similar to the one used in the embodiment illustrated in FIG. 3 .", "Under the applied electrical field, potassium ions in the regenerant stream migrate across the cation exchange connector 28 located near the inlet region of the ion reflux column 24 into the electrolyte reservoir 22 .", "Water is oxidized to form hydronium ions and oxygen gas at the anode located in the outlet 24 b of ion reflux column.", "Hydronium ions combine with the incoming sulfate ions to form sulfuric acid.", "In the meantime, hydroxide ions formed from the reduction of water at the cathode 54 combine with potassium ions to maintain the solution charge neutrality in the electrolyte reservoir.", "In this embodiment, the amount of current applied to the electrolytic regenerant recycle device 50 should be adjusted to a level that is sufficient to ensure the complete removal of potassium ions in the regenerant stream to convert potassium sulfate to sulfuric acid.", "In the embodiment shown in FIG. 5 , the ion reflux column 24 effluent contains the sulfuric acid regenerant and oxygen gas generated at the device anode and is directed to recycled back to the sulfuric acid regenerant reservoir 40 which is fitted with a vent port (not shown) to allow the release of oxygen gas into the ambient.", "In this embodiment, there is a consumption of water due to the oxidation reaction at the anode of the electrolytic regenerant recycle device 50 .", "The amount of water consumed is determined by the amount of current applied to the electrolytic regenerant recycle device 50 and rather minute under the typical ion chromatographic operating conditions.", "Therefore, the ion chromatography system illustrated in FIG. 5 provides a novel approach to recycle the sulfuric acid regenerant used in the operation of the chemically-regenerated suppressor in an ion chromatography system.", "FIG. 6 illustrates another preferred embodiment of ion chromatography systems in which the sulfuric acid regenerant used in the operation of an anion membrane suppressor is recycled.", "In this embodiment, the eluent used in the ion chromatographic process can be prepared by conventional means off-line or generated electrolytically on-line.", "The ion chromatographic process is performed using similar components described previously, except that a chemically-regenerated membrane suppressor system, suitably of the type described in FIG. 1 of U.S. Pat. No. 4,999,098, is used.", "In the embodiment illustrated in FIG. 6 , the sulfuric acid regenerant is delivered by a pump 41 from the regenerant reservoir 40 into the suppressor regenerant channel 36 b to supply hydronium ions used in the suppression of ion chromatographic eluent (KOH).", "The effluent from channel 36 b contains a mixture of potassium sulfate and sulfuric acid.", "The used regenerant liquid stream is then directed to the inlet of the ion reflux column in the electrolytic regenerant recycle device.", "The construction of the electrolytic regenerant recycle device 56 of the embodiment illustrated in FIG. 6 is similar to the one used in the embodiment illustrated in FIG. 4 .", "Device 56 serves the function of converting potassium sulfate in the suppressor effluent to sulfuric acid.", "The operation of device 56 in this embodiment is described below.", "Under the applied electrical field, potassium ions in the incoming regenerant solution migrate across the cation exchange connector 62 b located near the inlet region of device 56 into the cathode compartment 62 and combine with hydroxide ions generated at the cathode 62 a to form a potassium hydroxide solution.", "In the meantime, water is oxidized to form hydronium ions at the anode compartment 60 located near the outlet of the electrolytic regenerant recycle device 56 .", "Hydronium ions migrate across the cation exchange connector 60 to the resin bed 26 of device 56 and combine with sulfate to form sulfuric acid.", "In this embodiment, the amount of current applied to device 56 should be adjusted to a level that is sufficient to ensure the complete removal of potassium ions in the regenerant stream to convert potassium sulfate to sulfuric acid.", "The sulfuric acid regenerant solution is then recycled back to the regenerant reservoir 40 .", "The ion chromatography system illustrated in FIG. 6 provides another approach according to the invention to recycle the sulfuric acid regenerant used in the operation of the chemically-regenerated suppressor in an ion chromatography system.", "It should be pointed out that, by using appropriate anion exchange materials, the various embodiments described above can also be implemented in forms that are suitable for suppressing acid eluents for determination of cationic analytes.", "The following examples illustrate the present invention in ion chromatographic separation of ionic analytes EXAMPLE 1 Ion Chromatography System Using Electrolytic Eluent Generation with Recycled Source Ions and Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an ion chromatography (IC) system using electrolytic eluent generation with recycled source ions and electrolytic suppression with recycled regenerant water in the separation of common anions.", "The IC system used in the experiment was constructed according to the scheme shown in FIG. 1 .", "A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min.", "To generate and recycle a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of the KOH eluent generation and recycle module.", "The KOH eluent generation and recycle module was prepared by modifying a Dionex EGC-KOH cartridge (P/N 058900) through the addition of an ion reflux column placed in the potassium ion electrolyte reservoir which was filled with 1.0 liter of 0.5 M KOH.", "The ion reflux column was prepared by using a cylindrical PEEK housing that has cylindrical internal cavity of 9-mm ID×150 mm length which was packed with cation exchange resin in the hydronium form (8% cross-linked and 20-μm sulfonated styrene divinylbenzene resin beads, Dionex Corporation).", "The outlet of the column was fitted a flow-through Pt anode which was in direct physical contact with the cation exchange resin bed.", "The inlet region of the column was fitted with cation exchange connector that separated the resin bed from the potassium electrolyte solution in the ion source reservoir.", "A Dionex EG40 eluent generator control module was used to supply DC currents to the KOH eluent generation and recycle module.", "The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process.", "A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples.", "The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter.", "A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used.", "Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing.", "In this example, an electrolytic capillary suppressor was prepared as described below.", "The capillary anion suppressor consisted of three PEEK chambers.", "The eluent chamber contained a cation exchange capillary tubing embedded tightly inside a bed (8 mm ID×10 mm in length) of cation exchange resin (8% cross-linked and 20-μm sulfonated styrene divinylbenzene resin beads, Dionex Corporation).", "Provisions were made provide separate fluid connections to the cation exchange capillary tubing in the resin bed.", "A 15-cm length of a proprietary grafted and sulfonated TFE capillary tubing of 0.004-inch ID×0.010-inch OD (Dionex Corporation) was used in the construction of the electrolytic capillary anion suppressor.", "The eluent chamber was physically separated from the cathodic regenerant chamber and anodic regenerant chamber using proprietary grafted and sulfonated TFE cation exchange ion exchange membranes (Dionex Corporation).", "The cathode chamber contained a perforated Pt cathode and the anode chamber contains a perforated Pt anode.", "Both electrode chambers had two liquid connecting ports (inlet and outlet).", "In this example, the suppressed eluent from the outlet of the conductivity cell was routed to waste.", "A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min.", "The regenerant water was routed through the resin bed in eluent chamber, then to the anodic regenerant chamber and the cathodic regenerant chamber of the electrolytic anion suppressor.", "A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor.", "The catalytic gas elimination columns where hydrogen and oxygen gases react catalytically to form water were prepared by packing small strips of Pt foil in PEEK columns of 4-mm ID×50-mm length.", "One catalytic gas elimination column was placed downstream from the outlet of cathode chamber of the electrolytic suppressor.", "The other catalytic gas elimination column was placed downstream from the outlet of the ion reflux column.", "In one set of experiments, the KOH eluent generation and recycle module was programmed to generate and recycle 35 mM KOH at 10 μL/min by applying 0.563 mA of DC current to the device.", "The regenerant reservoir was initially filled with 100 mL of deionized water.", "The regenerant flow rate was 0.10 mL/min.", "The system was used to perform separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) continuously for more than 240 hours.", "No noticeable loss of regenerant water in the reservoir was observed over the period of 240 hours.", "If the regenerant water was not recycled, the consumption of regenerant water would have been 1440 mL.", "FIG. 7 shows the separation of five common anions obtained using the system shown in FIG. 1 by operating the electrolytic suppressor in the external water mode either with fresh regenerant water or with the recycled regenerant water.", "FIGS. 8 and 9 show the analyte retention time and peak area response reproducibility data obtained during the experiments.", "The results show that essentially identical separations were achieved under the conditions with or without recycling the regenerant water.", "For example, the average sulfate retention time was 6.25 minutes with a relative standard deviation (RDS) of 0.17 percent (n=24) and sulfate peak area response was 0.5822 μS·minute with a RDS of 0.91 percent (n=24) using over a period of 24 hours when the electrolytic suppressor was operated in the external water mode with fresh regenerant water.", "When the electrolytic suppressor was operated in the external water mode with recycled regenerant water, the average sulfate retention time was 6.23 minutes with a RDS of 0.36 percent (n=100) and sulfate peak area response was 0.5850 μS·minute with a RDS of 0.29 percent (n=100) using over a period of 100 hours.", "Therefore, the above results demonstrate that the ion chromatography system using electrolytic eluent generation with recycled source ions and electrolytic suppression with recycled regenerant water can be used to provide reliable determination of target anionic analytes.", "EXAMPLE 2 Ion Chromatography System Using Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an IC system using electrolytic suppression with recycled regenerant water in the separation of common anions.", "The IC system used in the experiment was constructed according to the embodiment shown in FIG. 3 .", "A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min.", "To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH eluent generator cartridge (P/N 058900).", "The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process.", "A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples.", "The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter.", "The electrolytic suppressor described in Example 1 was used.", "The suppressed eluent from the conductivity cell was routed to waste.", "A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min.", "A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor.", "A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used.", "A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing.", "The electrolytic regenerant recycle device was constructed by immersing an ion reflux column in a 100-mL reservoir filled with 0.5 M KOH solution.", "A Pt cathode was placed in the electrolyte reservoir of the electrolytic regenerant recycle device.", "The ion reflux column was prepared by using a cylindrical PEEK housing that has cylindrical internal cavity of 9-mm ID×150 mm length which was packed with cation exchange resin in the hydronium form.", "The outlet of the column was fitted a flow-through Pt anode which was in direct physical contact with the cation exchange resin bed.", "The inlet region of the column was fitted with cation exchange connector that separated the resin bed from the potassium electrolyte solution in the ion source reservoir.", "A Dionex SC20 control module was used to supply 2.0 mA of DC current to the electrolytic regenerant recycle device.", "One catalytic gas elimination column (4-mm ID×50-mm length) prepared by packing small strips of Pt foil was placed downstream from the outlet of cathode chamber of the electrolytic suppressor to allow the reaction of hydrogen and oxygen catalytically to form water.", "In one set of experiments, the regenerant reservoir was initially filled with 100 mL of deionized water.", "The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for 45 hours.", "No noticeable loss of regenerant water was observed over the period of 45 hours.", "If the regenerant water was not recycled, the consumption of water would have been 270 mL.", "The results show that identical separations were achieved under the conditions with or without recycling the regenerant water.", "During the period of 45 hours, the percent RDS of analyte retention time were 0.34% for chloride and 0.58% for sulfate (n=45);", "the percent RDS of analyte peak height response were 0.70% for fluoride and 0.69% for sulfate (n=45).", "Therefore, the above results demonstrate that the ion chromatography system with the recycled regenerant water shown in FIG. 3 can be used to provide reliable determination of target anionic analytes.", "EXAMPLE 3 Ion Chromatography System Using Electrolytic Suppression with Recycled Regenerant Water This example demonstrates the use of an IC system using electrolytic suppression with recycled regenerant water in the separation of common anions.", "The IC system used in the experiment was constructed according to the embodiment shown in FIG. 4 .", "A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min.", "To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH eluent generator cartridge (P/N 058900).", "The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process.", "A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples.", "The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter.", "The electrolytic suppressor described in Example 1 was used.", "The suppressed eluent from the conductivity cell was routed to the anode and cathode compartments of the electrolytic regenerant device before going to waste.", "A Dionex GS 50 pump was used to deliver the stream of regenerant water through a Dionex ATC HC column packed with anion exchange resin in the hydroxide form at 0.10 mL/min.", "A Dionex RFC30 module was used to supply a DC current of 25 mA to the electrolytic anion suppressor.", "A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used.", "A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing.", "In this example, a Dionex anion Atlas electrolytic suppressor (P/N 056116) was used as the electrolytic regenerant recycle device.", "A Dionex SC20 module was used to supply 5 mA of DC current to the electrolytic regenerant recycle device.", "One catalytic gas elimination column (4-mm ID×50-mm length) prepared by packing small strips of Pt foil was placed downstream from the outlet of cathode chamber of the electrolytic suppressor to allow the reaction of hydrogen and oxygen catalytically to form water.", "The effluent from the outlet of the catalytic gas elimination column was directed to the ELUENT IN port of the anion Atlas electrolytic suppressor.", "The effluent from the ELUENT OUT port of the anion Atlas electrolytic suppressor was recycled back to the regenerant reservoir.", "In one set of experiments, the regenerant reservoir was initially filled with 100 mL of deionized water.", "The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for 95 hours.", "No noticeable loss of regenerant water was observed over the period of 95 hours.", "If the regenerant water was not recycled, the consumption of water would have been 570 mL.", "During the period of 95 hours, the percent RDS of analyte retention time were 0.11% for chloride and 0.17% for sulfate (n=95);", "the percent RDS of analyte peak area response were 0.71% for chloride and 0.74% for sulfate (n=95).", "Therefore, the above results demonstrate that the ion chromatography system with the recycled regenerant water shown in FIG. 4 can be used to provide reliable determination of target anionic analytes.", "EXAMPLE 4 Ion Chromatography System Using Chemically-Regenerated Suppressor with Recycled Sulfuric Acid Regenerant This example demonstrates the use of an IC system using chemically-regenerated suppressor with recycled sulfuric acid regenerant in the separation of common anions.", "The IC system used in the experiment was constructed according to the embodiment shown in FIG. 6 .", "A modified Dionex P680 pump (Dionex Corporation, Sunnyvale, Calif.) was used to deliver deionized water at 10 μL/min.", "To generate a KOH eluent, deionized water was first passed through Dionex ATC-HC and CTC-1 columns to remove ionic contaminants and then routed into the KOH generation chamber of a Dionex EGC-KOH cartridge (P/N 058900).", "The outlet of the KOH eluent generator was connected to a high-pressure degas unit to remove hydrogen gas generated during the electrolytic eluent generation process.", "A Rheodyne PEEK high-pressure injection valve (Cotati, Calif.) was used for injection of samples.", "The capillary anion separation column was prepared by packing a proprietary Dionex surface-functionalized anion exchange resin in a 1/16-inch OD PEEK tubing of 250 mm in length and 380 μm in internal diameter.", "In this example, the anion suppressor described in Example 1 was used in the chemical regeneration mode using sulfuric acid as the regenerant.", "A Dionex GS 50 pump was used to deliver the stream of 20 mM sulfuric acid to the resin bed in the eluent chamber of the suppressor at 0.10 mL/min.", "A Dionex ED50A conductivity detector equipped with a modified flow-through conductivity cell was used.", "A Dionex Chromeleon 6.6 chromatography data management computer workstation was used for instrument control, data collection, and processing.", "In this example, a Dionex anion Atlas electrolytic suppressor (P/N 056116) was used as the electrolytic regenerant recycle device.", "A Dionex RFC-30 control module was used to supply 5 mA of DC current to the electrolytic regenerant recycle device.", "The effluent from the outlet of anion suppressor was directed to the ELUENT IN port of the anion Atlas electrolytic suppressor.", "The effluent from the ELUENT OUT port of the anion Atlas electrolytic suppressor was recycled back to the regenerant reservoir.", "In one set of experiments, the regenerant reservoir was initially filled with 125 mL of 20 mM sulfuric acid.", "The system was used to perform the separation of five common anions (fluoride, chloride, nitrate, sulfate, and phosphate) using 35 mM KOH at 10 μL/min continuously for more than 170 hours.", "No noticeable loss of sulfuric acid regenerant was observed over the period of 170 hours.", "If the sulfuric acid regenerant was not recycled, the consumption of 20 mM sulfuric acid would have been 1020 mL.", "During the period of 170 hours, the percent RDS of analyte retention time were 0.10% for chloride and 0.17% for sulfate (n=170);", "the percent RDS of analyte peak area response were 1.18% for chloride and 1.72% for sulfate (n=170).", "Therefore, the above results demonstrate that the ion chromatography system with the recycled sulfuric acid regenerant shown in FIG. 6 can be used to provide reliable determination of target anionic analytes." ]
BACKGROUND OF THE INVENTION The present invention relates to high strength aluminum base alloys and particularly to wrought high strength aluminum base alloys produced in extruded or hot-rolled plate form, which are well adapted for welding operations in further fabrication steps, wherein the strength properties are retained at high values, even exceeding about 40 ksi for the yield strength of extruded products and 30 ksi for hot rolled plate, without any necessity for interposing special heat treatment steps. The alloy compositions in accordance with this invention have been shown to meet the specified requirements and have furthermore surprisingly provided excellent solutions to the problems and disadvantages consistently associated with previous attempts to use prior art alloy compositions for such purposes. Such attempts were accompanied by inordinate loss of strength properties on welding, and/or a requirement after welding for special heat treatment and artificial aging steps to recover at least part of the lost strength properties, and/or an excessive tendency to undergo weld failures, such as under-bead weld cracks, and/or susceptibility to various types of corrosion, such as stress corrosion or exfoliation corrosion, which might result in excessive failures in service. Thus, at least one of the foregoing disadvantages, and usually several of them is encountered in attempts to weld previously known high-strength aluminum base alloys which include magnesium, silicon and copper as essential components, as occurs in such attempted use of AA Alloys 6066 and 6351, and of alloy compositions as disclosed in U.S. Pat. Nos. 3,498,221 and 3,935,007 and in British Pat. No. 1,383,895, also described in Journal of Metals (September, 1976), pages 15-18, which in general were formulated to accomplish purposes differing from the present objectives. Accordingly, it has been a principal object of the present invention to provide improved high strength aluminum base alloy compositions characterized by the capability of being welded readily without undergoing an excessive decrease in strength properties. A further object has been the provision of such alloy compositions characterized by the capability of being formed by extrusion or by hot-rolling procedures. Another object has been the provision of such alloy compositions comprising a defined range of magnesium content in conjunction with other essential elements in proportions required to achieve the desired functional characteristics. A further object has been the provision of such alloys characterized by heat-treatability and natural aging characteristics. Another object has been to provide such alloy compositions readily suitable for conversion to wrought products. Further objects and advantages of the present invention will be apparent from the following detailed description. SUMMARY OF THE INVENTION In accordance with the present invention, it has now been found that the above objects can be advantageously obtained by the provision of alloy compositions consisting essentially of 0.9-1.5% magnesium, 0.4-0.8% silicon, and 0.9-1.5% copper, wherein the copper must not exceed the sum of magnesium and silicon, and the silicon must not exceed the sum of 0.58 × percent Mg + 0.25 × percent (Mn + Fe). One or more of the group Cr, Mn, and Fe, is usually present, particularly in extrusion alloys, at a content of about 0.05-0.4% and the balance, other than added elements and usual impurities, is essentially aluminum. The added elements may be one or more of the following at the stated weight percentage ranges: 0.01-0.2 zirconium, 0.01-0.2 titanium, 0.01-0.2 vanadium, 0.01-0.4 cobalt, and 0.01-3.5 nickel. As will be discussed later, such additional elements are beneficial in the strengthening and stabilization of the wrought structure induced by hot working, through the formation of fine dispersed intermetallic precipitates. Other elements may be present as impurities in percentages up to about 0.05% each and totalling less than 0.15%, without adversely affecting the desired properties. In a preferred embodiment, the alloys of the present invention may contain 1.0-1.5% Mg, 0.4-0.7% Si, 1.0-1.5% Cu, and 0.2-0.4% of one or more additive elements selected from the group consisting of Mn, Fe and Cr, and the balance essentially aluminum. Alloys in accordance with this invention have enabled the attainment in articles, after thermal treatments met in welding, of yield strengths of over 30 or 40 ksi, without requiring processing other than natural aging. This represents a major advance over prior art practices and accomplishments, for example as summarized in Aluminum, Volume 3, American Society for Metals 1967), Chapter 12, especially, pages 407-415. In contrast, temper-rolled sheets of Alloy 5456, the highest strength composition in the non-heat-treatable 5000 series of aluminum alloys display a loss in strength properties after welding to values of yield strength and tensile strength characteristic of annealed metal. While certain heat-treatable Al base alloys could be chosen which displayed better retention of high strength values after welding, these gave rise to other problems and disadvantages such as cracked or otherwise unsatisfactory welds, inadequate corrosion resistance, or the need for special heat treatment procedures. In order to facilitate a comprehensive study aimed at establishing improved alloy compositions for this purpose, a simulated welding test was developed which would accurately indicate the strength properties resulting on the application of the welding procedure. This was accomplished by forming a single pass edge weld on each face of two plate halves 0.25 inch thick of 6061-T6 aluminum alloy, recording time-temperature curves for measured times up to 90 seconds and at a series of distances on each side of the weld. Hardness, tensile strength and yield strength values, and microstructure were determined for these points. This study established that the effects of low energy (corresponding to single pass) MIG welding (by electric arc under inert gas, using filler wire of alloy 5356 at rates of 15 and 30 inches per minute) could be reproduced by immersing a plate of sample alloy, 0.060 inch thick, in molten salt at 750° F. for 10 seconds and cooling in still air, and high energy welding (corresponding to multi-pass or repair conditions) could be reproduced by treatment in molten salt at 750° F. for 20 seconds. The above simulated welding test was found to accomplish a loss in hardness and strength properties and a change in microstructure corresponding to the changes determined to occur within a zone about 0.3 to 0.4 inch from the weld bead centerline. Thus, the initial tensile strength decreased from about 50 ksi to about 30 in the 10 second treatment and to about 25 in 20 seconds; the yield strength was lowered from 45 to about 20 in 10 seconds and to about 15 in 20 seconds. The study of microstructure established that the above zone, within which the tensile fractures during strength evaluation tests occurred, was characteristic of an overaged region containing coarsened particles of precipitated Mg 2 Si. Neither the welded plates nor the samples treated in molten salt displayed any natural aging after storage, that being precluded by the completeness of the precipitation during the treatment. The availability of the above-described simulated welding test enabled the completion of a series of screening tests of varied aluminum alloy compositions, the results of which indicated that the desired objectives might well be attainable through the enhancement of aluminum-magnesium-silicon alloys by increasing their initial strength properties, while providing against undue loss of strength during welding, at the same time improving the resistance to over-aging, and through the simultaneous imparting of a natural aging response, which would occur after the welding operation. As substantiated in the following specific examples, the objectives were attained by the compositions specified herein, within the determined ranges of the stated proportions and with strict observance of the maximum permissible limit of silicon in proportion to the content of magnesium, iron and manganese, and providing a copper content not in excess of the sum of magnesium plus silicon. The stated composition limits, as established by a comprehensive series of experiments, basically are those which have been found to provide the desired high strength and other essential properties, including weldability without the undue loss of strength, and to display satisfactory resistance to stress corrosion and to corrosion by various environments which might be encountered during use. The effective range of magnesium content is such as to provide increased initial strength properties effected through the presence of finely dispersed Mg 2 Si particles, as well as adequate retention of such properties through the welding cycle. Such effects are not obtained below the specified minimum content of Mg, while amounts of Mg exceeding the maximum are disadvantageous in increasing the tendency toward overaging during the welding treatment, with consequent undue losses in strength properties. Furthermore, the use of over 1.5% Mg in the alloy is disadvantageous, tending to effect a decreased resistance to stress corrosion. However, an excess of Mg in relation to Si is preferred, as tending to inhibit over-aging and to promote the recovery of strength through natural aging. The useful range of copper was established as between 0.9 and 1.5% as these proportions provided substantial increases in the initial strength properties, particularly in yield strength and tensile strength, increased the retention of strength during the welding operation, and imparted gains in strength through natural aging following welding. These features were not displayed to any substantial extent by compositions containing less Cu than the minimum. At above the maximum of 1.5% Cu, the strength retention effect was less marked, and the tendency toward deteriorating effects due to environmental corrosion was generally increased. The above effects in the beneficial range appear to be brought about by the introduction of additional phases and the substantially uniform distribution of the fine hardening intermetallic precipitates throughout the metal. A synergistic effect thereof is the precipitation of Mg 2 Si as tiny needles or rods rather than as large plates or grains found to occur in compositions containing insufficient proportions of copper. The specified range for the optional added elements, particularly manganese, iron, and chromium likewise states the limits within which the most effective initial strength increase and strength retention during welding are obtained, as the use of less than minimal proportions presents no substantial benefit and the presence of proportions higher than the maximum are correspondingly less effective and may introduce disadvantageous tendencies toward decreased corrosion resistance and impaired natural aging benefits. Similar effects exist with respect to departures from the specified range of silicon content, where it is also critical to observe the limitation that the Si content must not be more than corresponds to the sum of 0.58 × Mg content + 0.25 × content of (Mn + Fe). This limitation corresponds to the provision of excess magnesium over that required to combine with silicon to form precipitated silicide, which has been indicated to produce the most advantageous combination of desired properties, particularly of high initial strength, retention of strength during welding, and increase in strength by natural aging following the welding procedure. The presence of excess Si has been found to be notably disadvantageous with respect to the latter two of the above features. In contrast, the effect of excess magnesium is most evident under high energy welding conditions, where subsequent natural aging results in the most significant recovery of strength properties. DETAILED DESCRIPTION Compositions in accordance with the invention and comparison alloys were melted, fluxed by treatment with chlorine gas for 5 minutes or with a nitrogen-dichlorodifluoromethane mixture for 10 minutes, and cast as 5 pound Durville ingots, using a pouring temperature of 1320° F. The ingots, after homogenization at 930° F. for 24 hours, were cut into 4 inch square sections, 0.75 inch in thickness. These sections were hot rolled at 930° F. in a single pass to a thickness of 0.15 inch and water quenched. Such sections, requiring no solution treatment before aging, could be used to estimate the press quench effect which might be expected in commercial scale extrusions. A portion of the hot rolled plate was cold rolled to a thickness of 0.060 inch, solution annealed, water quenched, and aged for 18 hours at 320° F. to develop peak aging properties, denoted as -T6 temper. Another portion of the above hot rolled plate was tested after being aged for 18 hours at 320° F., denoted as -T5 temper. Tests on Al alloyed with 0.36 to 1.0% Mg and 0.25 to 1.5% Si at -T6 temper, prepared as described above, resulted in measured values of yield strength (Y) -- tensile strength (T) -- elongation (E), respectively, of 12 ksi -- 18 ksi -- 13 initially for an alloy of 0.36% Mg, 0.25% Si, and balance Al, and 4 -- 13 -- 28 after immersion for 10 seconds at 750° F. (simulated welding test). The corresponding values for an alloy of 0.71 Mg, 1.5 Si, and balance Al were 40 -- 44 -- 6 and 14 -- 22 -- 14, respectively. Ternary alloys of these elements in proportions between the above limits yielded intermediate values, with losses after the welding test ranging from 8 to 26 ksi in yield strength and from 5 to 22 ksi in tensile strength. Similar values of strength losses also resulted with similar alloys, each containing a small addition of Sn, Cd, Mn, Co, V, or Cr. This series also included three comparison Al alloys containing Mg, Si, and Cu, in proportions not in accordance with the present invention, which yielded test results similar to the above, as shown in Table I. TABLE I______________________________________ After 10 Secs. Initial At 750° FAlloy Mg Si Cu Al Y T E Y T E______________________________________1 0.66% 0.44% 0.25% Bal. 35-39-12 15-21-132 0.71 0.45 1.5 Bal 42-52-13 25-34-123 0.75 0.47 3.1 Bal 49-58-0 30-43-10______________________________________ In contrast, the following examples will be seen to substantiate the attainment of the objectives of the present invention by the provision of alloy compositions in accordance therewith. EXAMPLE I Alloy A, containing 1.38% Mg, 0.67% Si, 1.41% Cu, 0.39% Mn, balance Al (all percentages being by weight, unless otherwise indicated), tested at -T5 temper, displayed the following tensile properties initially, after 10 seconds at 750° F., after 20 seconds at 750° F., and following natural aging for 2 weeks after each treatment, shown in Table II. TABLE II______________________________________ Y T E______________________________________Initial 41 56 15After 10 Seconds at 750° F 33 45 13Then, aged 2 weeks 37 48 14After 20 Seconds at 750° F 26 39 14Then, aged 2 weeks 33 45 14______________________________________ Thus, the simulated low energy welding test caused a substantially smaller loss in tensile properties than resulted in the previous tests. Furthermore, natural aging following the high energy test (20 seconds) resulted in restoring much of the lost strength. EXAMPLE II Comparison alloys having the following compositions not in accordance with the invention were subjected at -T5 temper to the same tests as used in the previous example. TABLE III (a)______________________________________Alloy Mg Si Cu Other Al______________________________________4 0.50% 1.03% 0.02% .38 Fe, 0.49 Mn, Bal. 0.007 Ti, 0.043 Zn5 1.35 0.68 1.53 0.41 Mn Bal.6 1.35 0.74 0.54 0.42 Mn Bal.______________________________________ Test results were as follows: TABLE III (b)______________________________________Tensile Properties (Y-T-E)Com- After 10 Secs. After 20 Secs.pari- at 750° F at 750° Fson Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________4 38-43-12 18-26-17 21-29-15 12-22-21 13-23-205 33-45-16 21-33-17 24-35-13 14-30-20 19-35-196 25-35-15 18-29-18 19-30-18 13-25-20 12-26-21______________________________________ EXAMPLE III In contrast, significantly improved test results were obtained with alloys in accordance with the invention, included in Table IV. TABLE IV (a)______________________________________Alloy Mg Si Cu Other Al______________________________________B 1.35% 0.64% 1.45% 0.42% Fe Bal.C 1.00 0.77 1.44 0.42 Fe, 0.38 Mn Bal.D 1.41 0.59 1.45 0.18 Cr Bal.E 1.01 0.67 1.47 0.41 Fe, 0.19 Cr Bal.F 1.35 0.74 1.47 0.39 Fe, 0.38 Mn, Bal. 0.19 CrG 0.96 0.76 1.41 0.78 Mn Bal.H 1.35 0.58 1.41 0.14 Zr Bal.______________________________________ TABLE IV (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs. After 20 Secs. at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________B 39-53-17 35-45-13 37-48-13 24-36-13 31-42-14C 48-58-13 37-47-12 36-47-11 27-39-13 28-40-12D 37-52-16 35-45-14 36-47-16 27-38-15 32-44-16E 46-57-13 37-47-12 38-47-12 28-38-13 28-40-13F 44-56-14 34-46-12 35-47-12 24-39-14 28-44-14G 48-58-13 34-45-12 38-49-13 23-38-14 26-41-14H 41-53-17 32-41-13 36-45-13 24-36-14 29-41-13______________________________________ EXAMPLE IV Three commercial alloys were selected for direct comparison with alloys in accordance with the invention, yielding test results, as listed in Table V. TABLE V (a)______________________________________Alloy Mg Si Cu Mn Cr Others Al______________________________________7 (6351) 0.5% 1.03% 0.02% 0.49% -- 0.38 Fe Bal.8 (7006) 2.40 -- -- 0.19 0.09 4.53 Zn Bal.9 (7039) 2.8 0.072 0.10 0.11 0.17 4.41 Zn Bal.______________________________________ TABLE V (b)__________________________________________________________________________ Tensile Properties (Y-T-E) After 10 Secs. at 750° F After 20 Secs. at 750° FAlloyInitial Immediate Aged 2 weeks Immediate Aged 2 weeks__________________________________________________________________________7 (6351)38-43-12 18-26-17 21-29-15 12-22-21 13-23-208 (7006)55-63-12 21-40-19 28-50-18 22-42-21 30-52-229 (7039)57-65-11 30-48-16 29-49-15 23-45-19 34-58-18__________________________________________________________________________ EXAMPLE V Parallel test results listed in Table VI for three alloys in accordance with the present invention substantiate their significantly superior results. TABLE VI (a)______________________________________Alloy Mg Si Cu Other Al______________________________________J 1.4% 0.64% 1.3% 0.41% Mn Bal.K 0.95 0.70 1.38 0.41 Mn, 0.21 Cr Bal.A 1.38 0.67 1.41 0.39 Mn Bal.______________________________________ TABLE VI (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs. After 20 Secs. at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________J 43-54-18 34-43- 35-44-15 24-37-14 30-44-15K 48-58-13 41-50-12 40-51-12 26-39-13 28-41-12A 41-56-15 33-45-13 37-48-14 26-39-14 33-45-14______________________________________ The comparisons afforded by the above two examples show that preferred alloys in accordance with this invention, after low energy welding and natural aging, are substantially superior to the commercial alloys. After high energy welding and natural aging, the present alloys display over twice the strength of 6351 and have tensile properties comparable to those of alloys 7006 and 7039, but without their operational disadvantages. EXAMPLE VI This example substantiates the disadvantageous effects which occur when the silicon is present in the alloy in an excess amount, such as to be greater than can be precipitated as a silicide of magnesium or other metal. The alloys listed in Table VII (a) were prepared as in the preceding examples and the test results are summarized in Table VII (b), the "Initial" values having been measured on samples prepared at T5 temper. TABLE VII (a)______________________________________Alloy Mg Si Cu Mn Al Excess Si______________________________________10 0.95% 0.56% 1.46% -- Bal. 0.01%11 0.95 0.69 1.4 0.42 Bal. 0.0412 1.00 1.00 1.45 0.44 Bal. 0.31______________________________________ TABLE VII (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs. After 20 Secs. at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________10 46-56-15 37-45-12 37-45-12 26-37-13 29-38-1211 50-58-13 38-45-10 36-45-12 27-38-12 27-39-1212 53-60-13 35-44-10 35-43-12 27-39-12 28-40-11______________________________________ Thus, the present invention provides aluminum base alloys of high strength, capable of retaining adequate strength after being subjected to operations at elevated temperatures, as in fusion welding processes, corresponding to retained yield strength of about 40 ksi or higher for extruded products or somewhat less for hot rolled plate. Strong crack-free welds are consistently and readily obtainable with the present alloys and they show excellent formability for conversion to products having good resistance to stress corrosion and other corrosive influences. Accordingly, these alloys are well adapted for use in varied commercial fields, as in automotive vehicle bodies and components, such as for tanks and containers. The above description and specific examples substantiate the attainment of the specified objectives of this invention in accordance with the alloy compositions and preferred treatment procedures set forth. It will be understood by those skilled in the art that various modifications may at times be employed advantageously in the illustrative examples, within the scope of the appended claims.
High strength extrudable and readily weldable aluminum base alloys are prepared comprising 0.9-1.5% magnesium, 0.4-0.8% silicon, and 0.9-1.5% copper, which may also include optional elements such as manganese, iron, and chromium, wherein the silicon content must not exceed the sum of 0.58 × magnesium content plus 0.25 × the manganese plus iron contents and the copper content must not exceed the sum of magnesium plus silicon contents. Such alloys display improved retention of strength properties after being subjected to welding conditions.
Provide a concise summary of the essential information conveyed in the context.
[ "BACKGROUND OF THE INVENTION The present invention relates to high strength aluminum base alloys and particularly to wrought high strength aluminum base alloys produced in extruded or hot-rolled plate form, which are well adapted for welding operations in further fabrication steps, wherein the strength properties are retained at high values, even exceeding about 40 ksi for the yield strength of extruded products and 30 ksi for hot rolled plate, without any necessity for interposing special heat treatment steps.", "The alloy compositions in accordance with this invention have been shown to meet the specified requirements and have furthermore surprisingly provided excellent solutions to the problems and disadvantages consistently associated with previous attempts to use prior art alloy compositions for such purposes.", "Such attempts were accompanied by inordinate loss of strength properties on welding, and/or a requirement after welding for special heat treatment and artificial aging steps to recover at least part of the lost strength properties, and/or an excessive tendency to undergo weld failures, such as under-bead weld cracks, and/or susceptibility to various types of corrosion, such as stress corrosion or exfoliation corrosion, which might result in excessive failures in service.", "Thus, at least one of the foregoing disadvantages, and usually several of them is encountered in attempts to weld previously known high-strength aluminum base alloys which include magnesium, silicon and copper as essential components, as occurs in such attempted use of AA Alloys 6066 and 6351, and of alloy compositions as disclosed in U.S. Pat. Nos. 3,498,221 and 3,935,007 and in British Pat. No. 1,383,895, also described in Journal of Metals (September, 1976), pages 15-18, which in general were formulated to accomplish purposes differing from the present objectives.", "Accordingly, it has been a principal object of the present invention to provide improved high strength aluminum base alloy compositions characterized by the capability of being welded readily without undergoing an excessive decrease in strength properties.", "A further object has been the provision of such alloy compositions characterized by the capability of being formed by extrusion or by hot-rolling procedures.", "Another object has been the provision of such alloy compositions comprising a defined range of magnesium content in conjunction with other essential elements in proportions required to achieve the desired functional characteristics.", "A further object has been the provision of such alloys characterized by heat-treatability and natural aging characteristics.", "Another object has been to provide such alloy compositions readily suitable for conversion to wrought products.", "Further objects and advantages of the present invention will be apparent from the following detailed description.", "SUMMARY OF THE INVENTION In accordance with the present invention, it has now been found that the above objects can be advantageously obtained by the provision of alloy compositions consisting essentially of 0.9-1.5% magnesium, 0.4-0.8% silicon, and 0.9-1.5% copper, wherein the copper must not exceed the sum of magnesium and silicon, and the silicon must not exceed the sum of 0.58 × percent Mg + 0.25 × percent (Mn + Fe).", "One or more of the group Cr, Mn, and Fe, is usually present, particularly in extrusion alloys, at a content of about 0.05-0.4% and the balance, other than added elements and usual impurities, is essentially aluminum.", "The added elements may be one or more of the following at the stated weight percentage ranges: 0.01-0.2 zirconium, 0.01-0.2 titanium, 0.01-0.2 vanadium, 0.01-0.4 cobalt, and 0.01-3.5 nickel.", "As will be discussed later, such additional elements are beneficial in the strengthening and stabilization of the wrought structure induced by hot working, through the formation of fine dispersed intermetallic precipitates.", "Other elements may be present as impurities in percentages up to about 0.05% each and totalling less than 0.15%, without adversely affecting the desired properties.", "In a preferred embodiment, the alloys of the present invention may contain 1.0-1.5% Mg, 0.4-0.7% Si, 1.0-1.5% Cu, and 0.2-0.4% of one or more additive elements selected from the group consisting of Mn, Fe and Cr, and the balance essentially aluminum.", "Alloys in accordance with this invention have enabled the attainment in articles, after thermal treatments met in welding, of yield strengths of over 30 or 40 ksi, without requiring processing other than natural aging.", "This represents a major advance over prior art practices and accomplishments, for example as summarized in Aluminum, Volume 3, American Society for Metals 1967), Chapter 12, especially, pages 407-415.", "In contrast, temper-rolled sheets of Alloy 5456, the highest strength composition in the non-heat-treatable 5000 series of aluminum alloys display a loss in strength properties after welding to values of yield strength and tensile strength characteristic of annealed metal.", "While certain heat-treatable Al base alloys could be chosen which displayed better retention of high strength values after welding, these gave rise to other problems and disadvantages such as cracked or otherwise unsatisfactory welds, inadequate corrosion resistance, or the need for special heat treatment procedures.", "In order to facilitate a comprehensive study aimed at establishing improved alloy compositions for this purpose, a simulated welding test was developed which would accurately indicate the strength properties resulting on the application of the welding procedure.", "This was accomplished by forming a single pass edge weld on each face of two plate halves 0.25 inch thick of 6061-T6 aluminum alloy, recording time-temperature curves for measured times up to 90 seconds and at a series of distances on each side of the weld.", "Hardness, tensile strength and yield strength values, and microstructure were determined for these points.", "This study established that the effects of low energy (corresponding to single pass) MIG welding (by electric arc under inert gas, using filler wire of alloy 5356 at rates of 15 and 30 inches per minute) could be reproduced by immersing a plate of sample alloy, 0.060 inch thick, in molten salt at 750° F. for 10 seconds and cooling in still air, and high energy welding (corresponding to multi-pass or repair conditions) could be reproduced by treatment in molten salt at 750° F. for 20 seconds.", "The above simulated welding test was found to accomplish a loss in hardness and strength properties and a change in microstructure corresponding to the changes determined to occur within a zone about 0.3 to 0.4 inch from the weld bead centerline.", "Thus, the initial tensile strength decreased from about 50 ksi to about 30 in the 10 second treatment and to about 25 in 20 seconds;", "the yield strength was lowered from 45 to about 20 in 10 seconds and to about 15 in 20 seconds.", "The study of microstructure established that the above zone, within which the tensile fractures during strength evaluation tests occurred, was characteristic of an overaged region containing coarsened particles of precipitated Mg 2 Si.", "Neither the welded plates nor the samples treated in molten salt displayed any natural aging after storage, that being precluded by the completeness of the precipitation during the treatment.", "The availability of the above-described simulated welding test enabled the completion of a series of screening tests of varied aluminum alloy compositions, the results of which indicated that the desired objectives might well be attainable through the enhancement of aluminum-magnesium-silicon alloys by increasing their initial strength properties, while providing against undue loss of strength during welding, at the same time improving the resistance to over-aging, and through the simultaneous imparting of a natural aging response, which would occur after the welding operation.", "As substantiated in the following specific examples, the objectives were attained by the compositions specified herein, within the determined ranges of the stated proportions and with strict observance of the maximum permissible limit of silicon in proportion to the content of magnesium, iron and manganese, and providing a copper content not in excess of the sum of magnesium plus silicon.", "The stated composition limits, as established by a comprehensive series of experiments, basically are those which have been found to provide the desired high strength and other essential properties, including weldability without the undue loss of strength, and to display satisfactory resistance to stress corrosion and to corrosion by various environments which might be encountered during use.", "The effective range of magnesium content is such as to provide increased initial strength properties effected through the presence of finely dispersed Mg 2 Si particles, as well as adequate retention of such properties through the welding cycle.", "Such effects are not obtained below the specified minimum content of Mg, while amounts of Mg exceeding the maximum are disadvantageous in increasing the tendency toward overaging during the welding treatment, with consequent undue losses in strength properties.", "Furthermore, the use of over 1.5% Mg in the alloy is disadvantageous, tending to effect a decreased resistance to stress corrosion.", "However, an excess of Mg in relation to Si is preferred, as tending to inhibit over-aging and to promote the recovery of strength through natural aging.", "The useful range of copper was established as between 0.9 and 1.5% as these proportions provided substantial increases in the initial strength properties, particularly in yield strength and tensile strength, increased the retention of strength during the welding operation, and imparted gains in strength through natural aging following welding.", "These features were not displayed to any substantial extent by compositions containing less Cu than the minimum.", "At above the maximum of 1.5% Cu, the strength retention effect was less marked, and the tendency toward deteriorating effects due to environmental corrosion was generally increased.", "The above effects in the beneficial range appear to be brought about by the introduction of additional phases and the substantially uniform distribution of the fine hardening intermetallic precipitates throughout the metal.", "A synergistic effect thereof is the precipitation of Mg 2 Si as tiny needles or rods rather than as large plates or grains found to occur in compositions containing insufficient proportions of copper.", "The specified range for the optional added elements, particularly manganese, iron, and chromium likewise states the limits within which the most effective initial strength increase and strength retention during welding are obtained, as the use of less than minimal proportions presents no substantial benefit and the presence of proportions higher than the maximum are correspondingly less effective and may introduce disadvantageous tendencies toward decreased corrosion resistance and impaired natural aging benefits.", "Similar effects exist with respect to departures from the specified range of silicon content, where it is also critical to observe the limitation that the Si content must not be more than corresponds to the sum of 0.58 × Mg content + 0.25 × content of (Mn + Fe).", "This limitation corresponds to the provision of excess magnesium over that required to combine with silicon to form precipitated silicide, which has been indicated to produce the most advantageous combination of desired properties, particularly of high initial strength, retention of strength during welding, and increase in strength by natural aging following the welding procedure.", "The presence of excess Si has been found to be notably disadvantageous with respect to the latter two of the above features.", "In contrast, the effect of excess magnesium is most evident under high energy welding conditions, where subsequent natural aging results in the most significant recovery of strength properties.", "DETAILED DESCRIPTION Compositions in accordance with the invention and comparison alloys were melted, fluxed by treatment with chlorine gas for 5 minutes or with a nitrogen-dichlorodifluoromethane mixture for 10 minutes, and cast as 5 pound Durville ingots, using a pouring temperature of 1320° F. The ingots, after homogenization at 930° F. for 24 hours, were cut into 4 inch square sections, 0.75 inch in thickness.", "These sections were hot rolled at 930° F. in a single pass to a thickness of 0.15 inch and water quenched.", "Such sections, requiring no solution treatment before aging, could be used to estimate the press quench effect which might be expected in commercial scale extrusions.", "A portion of the hot rolled plate was cold rolled to a thickness of 0.060 inch, solution annealed, water quenched, and aged for 18 hours at 320° F. to develop peak aging properties, denoted as -T6 temper.", "Another portion of the above hot rolled plate was tested after being aged for 18 hours at 320° F., denoted as -T5 temper.", "Tests on Al alloyed with 0.36 to 1.0% Mg and 0.25 to 1.5% Si at -T6 temper, prepared as described above, resulted in measured values of yield strength (Y) -- tensile strength (T) -- elongation (E), respectively, of 12 ksi -- 18 ksi -- 13 initially for an alloy of 0.36% Mg, 0.25% Si, and balance Al, and 4 -- 13 -- 28 after immersion for 10 seconds at 750° F. (simulated welding test).", "The corresponding values for an alloy of 0.71 Mg, 1.5 Si, and balance Al were 40 -- 44 -- 6 and 14 -- 22 -- 14, respectively.", "Ternary alloys of these elements in proportions between the above limits yielded intermediate values, with losses after the welding test ranging from 8 to 26 ksi in yield strength and from 5 to 22 ksi in tensile strength.", "Similar values of strength losses also resulted with similar alloys, each containing a small addition of Sn, Cd, Mn, Co, V, or Cr.", "This series also included three comparison Al alloys containing Mg, Si, and Cu, in proportions not in accordance with the present invention, which yielded test results similar to the above, as shown in Table I. TABLE I______________________________________ After 10 Secs.", "Initial At 750° FAlloy Mg Si Cu Al Y T E Y T E______________________________________1 0.66% 0.44% 0.25% Bal.", "35-39-12 15-21-132 0.71 0.45 1.5 Bal 42-52-13 25-34-123 0.75 0.47 3.1 Bal 49-58-0 30-43-10______________________________________ In contrast, the following examples will be seen to substantiate the attainment of the objectives of the present invention by the provision of alloy compositions in accordance therewith.", "EXAMPLE I Alloy A, containing 1.38% Mg, 0.67% Si, 1.41% Cu, 0.39% Mn, balance Al (all percentages being by weight, unless otherwise indicated), tested at -T5 temper, displayed the following tensile properties initially, after 10 seconds at 750° F., after 20 seconds at 750° F., and following natural aging for 2 weeks after each treatment, shown in Table II.", "TABLE II______________________________________ Y T E______________________________________Initial 41 56 15After 10 Seconds at 750° F 33 45 13Then, aged 2 weeks 37 48 14After 20 Seconds at 750° F 26 39 14Then, aged 2 weeks 33 45 14______________________________________ Thus, the simulated low energy welding test caused a substantially smaller loss in tensile properties than resulted in the previous tests.", "Furthermore, natural aging following the high energy test (20 seconds) resulted in restoring much of the lost strength.", "EXAMPLE II Comparison alloys having the following compositions not in accordance with the invention were subjected at -T5 temper to the same tests as used in the previous example.", "TABLE III (a)______________________________________Alloy Mg Si Cu Other Al______________________________________4 0.50% 1.03% 0.02% [.", "].38 Fe, 0.49 Mn, Bal.", "0.007 Ti, 0.043 Zn5 1.35 0.68 1.53 0.41 Mn Bal[.", "].6 1.35 0.74 0.54 0.42 Mn Bal.", "______________________________________ Test results were as follows: TABLE III (b)______________________________________Tensile Properties (Y-T-E)Com- After 10 Secs.", "After 20 Secs.", "pari- at 750° F at 750° Fson Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________4 38-43-12 18-26-17 21-29-15 12-22-21 13-23-205 33-45-16 21-33-17 24-35-13 14-30-20 19-35-196 25-35-15 18-29-18 19-30-18 13-25-20 12-26-21______________________________________ EXAMPLE III In contrast, significantly improved test results were obtained with alloys in accordance with the invention, included in Table IV.", "TABLE IV (a)______________________________________Alloy Mg Si Cu Other Al______________________________________B 1.35% 0.64% 1.45% 0.42% Fe Bal.", "C 1.00 0.77 1.44 0.42 Fe, 0.38 Mn Bal.", "D 1.41 0.59 1.45 0.18 Cr Bal.", "E 1.01 0.67 1.47 0.41 Fe, 0.19 Cr Bal.", "F 1.35 0.74 1.47 0.39 Fe, 0.38 Mn, Bal.", "0.19 CrG 0.96 0.76 1.41 0.78 Mn Bal.", "H 1.35 0.58 1.41 0.14 Zr Bal.", "______________________________________ TABLE IV (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs.", "After 20 Secs.", "at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________B 39-53-17 35-45-13 37-48-13 24-36-13 31-42-14C 48-58-13 37-47-12 36-47-11 27-39-13 28-40-12D 37-52-16 35-45-14 36-47-16 27-38-15 32-44-16E 46-57-13 37-47-12 38-47-12 28-38-13 28-40-13F 44-56-14 34-46-12 35-47-12 24-39-14 28-44-14G 48-58-13 34-45-12 38-49-13 23-38-14 26-41-14H 41-53-17 32-41-13 36-45-13 24-36-14 29-41-13______________________________________ EXAMPLE IV Three commercial alloys were selected for direct comparison with alloys in accordance with the invention, yielding test results, as listed in Table V. TABLE V (a)______________________________________Alloy Mg Si Cu Mn Cr Others Al______________________________________7 (6351) 0.5% 1.03% 0.02% 0.49% -- 0.38 Fe Bal[.", "].8 (7006) 2.40 -- -- 0.19 0.09 4.53 Zn Bal[.", "].9 (7039) 2.8 0.072 0.10 0.11 0.17 4.41 Zn Bal.", "______________________________________ TABLE V (b)__________________________________________________________________________ Tensile Properties (Y-T-E) After 10 Secs.", "at 750° F After 20 Secs.", "at 750° FAlloyInitial Immediate Aged 2 weeks Immediate Aged 2 weeks__________________________________________________________________________7 (6351)38-43-12 18-26-17 21-29-15 12-22-21 13-23-208 (7006)55-63-12 21-40-19 28-50-18 22-42-21 30-52-229 (7039)57-65-11 30-48-16 29-49-15 23-45-19 34-58-18__________________________________________________________________________ EXAMPLE V Parallel test results listed in Table VI for three alloys in accordance with the present invention substantiate their significantly superior results.", "TABLE VI (a)______________________________________Alloy Mg Si Cu Other Al______________________________________J 1.4% 0.64% 1.3% 0.41% Mn Bal.", "K 0.95 0.70 1.38 0.41 Mn, 0.21 Cr Bal.", "A 1.38 0.67 1.41 0.39 Mn Bal.", "______________________________________ TABLE VI (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs.", "After 20 Secs.", "at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________J 43-54-18 34-43- 35-44-15 24-37-14 30-44-15K 48-58-13 41-50-12 40-51-12 26-39-13 28-41-12A 41-56-15 33-45-13 37-48-14 26-39-14 33-45-14______________________________________ The comparisons afforded by the above two examples show that preferred alloys in accordance with this invention, after low energy welding and natural aging, are substantially superior to the commercial alloys.", "After high energy welding and natural aging, the present alloys display over twice the strength of 6351 and have tensile properties comparable to those of alloys 7006 and 7039, but without their operational disadvantages.", "EXAMPLE VI This example substantiates the disadvantageous effects which occur when the silicon is present in the alloy in an excess amount, such as to be greater than can be precipitated as a silicide of magnesium or other metal.", "The alloys listed in Table VII (a) were prepared as in the preceding examples and the test results are summarized in Table VII (b), the "Initial"", "values having been measured on samples prepared at T5 temper.", "TABLE VII (a)______________________________________Alloy Mg Si Cu Mn Al Excess Si______________________________________10 0.95% 0.56% 1.46% -- Bal.", "0.01%11 0.95 0.69 1.4 0.42 Bal.", "0.0412 1.00 1.00 1.45 0.44 Bal.", "0.31______________________________________ TABLE VII (b)______________________________________Tensile Properties (Y-T-E) After 10 Secs.", "After 20 Secs.", "at 750° F at 750° F Aged AgedAlloy Initial Immediate 2 weeks Immediate 2 weeks______________________________________10 46-56-15 37-45-12 37-45-12 26-37-13 29-38-1211 50-58-13 38-45-10 36-45-12 27-38-12 27-39-1212 53-60-13 35-44-10 35-43-12 27-39-12 28-40-11______________________________________ Thus, the present invention provides aluminum base alloys of high strength, capable of retaining adequate strength after being subjected to operations at elevated temperatures, as in fusion welding processes, corresponding to retained yield strength of about 40 ksi or higher for extruded products or somewhat less for hot rolled plate.", "Strong crack-free welds are consistently and readily obtainable with the present alloys and they show excellent formability for conversion to products having good resistance to stress corrosion and other corrosive influences.", "Accordingly, these alloys are well adapted for use in varied commercial fields, as in automotive vehicle bodies and components, such as for tanks and containers.", "The above description and specific examples substantiate the attainment of the specified objectives of this invention in accordance with the alloy compositions and preferred treatment procedures set forth.", "It will be understood by those skilled in the art that various modifications may at times be employed advantageously in the illustrative examples, within the scope of the appended claims." ]
BACKGROUND OF THE INVENTION This invention relates to new and useful improvements in electrochemical detection procedures for the determination of glucose in biological fluids. The determination of glucose in biological fluids is probably the most requested laboratory test. Glucose measurements are commonly performed on whole blood, serum, urine and cerebrospinal fluid samples. Carbohydrate production is affected in numerous physiological and pathological conditions. For example, elevations of blood glucose have been observed in pancreatic disease, severe thyrotoxicosis, diabetes Mellitus, Phaeochromocytoma, pituitary and adrenal disorders, etc. Similarly, decreases of blood glucose have been observed in pancreatic islet cell hyperplasia, insulin overdosage, adrenal cortical insufficiency, hypopituitarism, acute infections, liver disease, poisonings and the like. Colorimetric procedures employing 3,5-dinitrosalicyclic acid (3,5-DNSA) for the determination of glucose and other reducing substances are well documented throughout the chemical literature (see Refs. 1-20). Furthermore, specificity for glucose is claimed (Refs. 4,7,14) and attributed to the physiologic context in which the method is employed (Ref. 7). Modified colorimetric procedures have been developed for the analysis of reducing sugars in blood (Refs. 4, 15,16), urine (Refs. 7,14,16-19) and for a variety of nutrients (Refs. 5,6,11) e.g. beet pulp, oatmeal cereal, milk, strawberries, vegetables and the like. Automated procedures are described for routine blood (Ref. 4) and urine (Ref. 7) sugar analyses. Recently, saccharogenic detection systems have been adapted to determine serum (Refs. 2,8-10), and urine (Ref. 10) amylase. These saccharogenic amylase methods are reported to be superior to conventional iodometric procedures (Ref. 8). SUMMARY OF THE INVENTION The process described herein may be employed to determine the concentration of glucose in serum samples. Modified procedures employing the same principle may similarly be developed to measure glucose in other fluids or solids brought into solution. The process, with or without modification, may be adapted to polarographic and other electrochemical apparatus currently available, or specific analyzers may more economically be built to monitor the decrease of the functional nitro group or groups contained in the reagent employed e.g. 2,4-DNP, 3,5-DNSA, 3,5-DNBA, or other aromatic nitro containing compound. The quantitative detection procedure described herein for the electrochemical determination of glucose and other reducing substances is nitro reaction group specific and more sensitive than previously reported colorimetric procedures. Chromogenic and turbidimetric interferences are eliminated due to the nature of the detection system. In accordance with the invention there is provided a process for the electrochemical determination of the concentration of glucose in a sample of serum, other fluid or solid brought into solution; whereby, the sample is reacted at elevated temperatures in an alkaline medium containing an aromatic reagent with one or more attached nitro groups. The resulting chemical changes, which the reactive nitro group or groups have undergone, are monitored by electrodes in terms of current changes and the glucose concentration of the sample is established by conventional techniques such as calibration curves, standard addition process, and the like. In the analyses included herein by way of examples, the following chemicals were obtained from Fisher Scientific Co., Fair Lawn, N.J.: Fisher Certified anhydrous D-glucose, sodium hydroxide, sodium chloride, 3,5-dinitrobenzoic acid (3,5-DNBA) and reagent grade 2,4-dinitrophenol (2,4-DNP). Reagent grade 3,5-dinitrosalicylic acid was purchased from the Eastman Kodak Co., Rochester, N.Y. Triple distilled mercury was obtained from Engelhard Industries of Canada, Ltd., Toronto, Ontario. Certified quality nitrogen was supplied by Canadian Liquid Air, Ltd. However other sources of chemicals can of course be used. All analyses were performed in a 10-ml Heyrovsky polarographic cell. A dropping mercury electrode (DME) was the indicator electrode and a mercury pool served as the reference electrode. The characteristics of the capillary used were: m=0.596 mg s -1 , t=1s, m 2/3 t 1/6 =0.708 mg 2/3 x 1/2 for a drop time setting of 1 second, and m=0.566 mg s -1 , t=2 s, m 2/3 t 1/6 =0.767 mg 2/3 s 1/2 for a drop-time setting of 2 seconds. Polarographic analysis was performed with a Model 170 Electrochemistry System from the Princeton Applied Research Corporation, Princeton, N.J., U.S.A. The above data are for reference purposes only. With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of a typical embodiment of the principles of the present invention, in which: DESCRIPTION OF THE DRAWINGS FIG. 1 is a plot showing the diffusion current results of the reaction of glucose with 2,4-Dinitrophenol plotted versus the glucose: 2,4-DNP ratio. FIG. 2 is a plot of the difference in diffusion current of the effect of base concentration on the reactivity of glucose with 3,5-Dinitrosalicylic Acid, plotted versus the concentration of NaOH. FIG. 3 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrosalicylic acid in 0.25 N NaOH, plotted versus the glucose: 3,5-DNSA molar ratio. FIG. 4 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrosalicylic acid in 3.0 N NaOH, plotted versus the glucose: 3,5-DNSA molar ratio. FIG. 5 is a plot of the difference in diffusion current of the effect of base concentration of the reactivity of glucose with 3,5-Dinitrobenzoic acid, plotted versus the concentration of NaOH. FIG. 6 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrobenzoic acid in 0.75 N NaOH, plotted versus the glucose: 3,5-DNBA molar ratio. FIG. 7 is a plot of the total diffusion current for the nitro group reduction waves plotted versus the quantity of glucose added to glucose in serum. FIG. 8 is a plot of the total diffusion current for the nitro group reduction waves plotted versus the quantity of glucose added to glucose in urine. In the drawings like characters of reference indicate corresponding parts in the different figures. DETAILED DESCRIPTION Proceeding therefore to describe the invention in detail, the following methods were used in preparing the necessary standards: Reaction of Glucose with 2,4-Dinitrophenol Fourteen milligrams of 2,4-dinitrophenol and 25 milliliters of 1.0 N NaOH were added to a 50-ml volumetric flask which was brought to volume with distilled water. This produced a 1.5×10 -3 M 2,4-DNP stock standard. A 7.5×10 -2 M glucose solution was prepared by adding 1.3512 g of glucose to a 100-ml volumetric flask which was brought to volume with distilled water. Twenty microliters of the glucose solution and 2.5 milliliters of the 2,4-dinitrophenol stock were pipetted into a 10-ml volumetric flask using a Gilford automatic pipetter/diluter. This resulted in a glucose: 2,4-DNP molar ratio of 0.4. The solution was mixed, heated in a boiling water bath for 5 minutes, cooled, and brought to volume with distilled water. Five milliliters were transferred into a 10-ml volumetric flask. Two and a half milliliters of 1.0 N NaOH were added and the flask was mixed and brought to volume with distilled water. This working standard was transferred into a 10-ml Heyrovsky cell which contained a small pool of mercury on the floor of the cell to act as the anodic reference electrode. The Heyrovsky cell was placed under a dropping mercury electrode onto which a drop timer was attached. The mercury reservoir was raised to a height of 59.0 cm. Polarograms were recorded throughout the voltage range of -0.3 to -1.75 volts. A series of working standards was similarly prepared by increasing the glucose concentration to produce molar ratios between 0.4:1 and 2:1 in increments of 0.4. All working standards and appropriate reagent blanks were tested as described above. The total diffusion current for the first and second nitro group reduction waves was determined by measuring the vertical distance from the residual current to the limiting current. The diffusion current results were plotted versus the glucose: 2,4-DNP ratio (Table I and FIG. 1). TABLE I______________________________________Effect of Glucose Concentration on the Total DiffusionCurrent of the 2,4-DNP Reduction Waves Total Diffusion CurrentGlucose/2,4-DNP Ratio (μA)______________________________________0 6.570.4 6.140.8 5.871.2 5.541.6 4.922.0 4.57______________________________________ The Effect of Base Concentration on the Reactivity of Glucose with 3,5-Dinitrosalicylic Acid Five milliliters of a stock solution of 3,5-dinitrosalicylic acid, 8×10 -4 M 3,5-DNSA in 0.6 N NaOH, were transferred to a 10-ml volumetric flask. A volume of 0.1 ml of an aqueous 4×10 -2 M glucose standard was added and the solution was mixed. The flask was placed in a boiling water bath for five minutes, cooled, and brought to volume with distilled water. Polarographic analysis was performed as previously described. A blank test was similarly performed in the absence of glucose. The difference in the diffusion current (ΔI d ) was calculated from the blank and test results (Table II). The above testing process was similarly performed for solutions containing NaOH at the following final molar concentrations: 1.0, 1.5, 2.0, 2.5, and 3.0. The ΔI d results were plotted versus the concentration of NaOH (FIG. 2). TABLE II______________________________________Effect of Base Concentration on the DiffusionCurrent of the 3,5-DNSA-Glucose ReactionFinal NaOH Change inConcentration Diffusion Current(N) (ΔI.sub.d in μA)______________________________________0.3 0.551.0 1.281.5 1.502.0 1.422.5 1.593.0 1.79______________________________________ Reaction of Glucose with 3,5-Dinitrosalicylic acid in 0.25 N NaOH An 8.0×10 -4 M stock solution of 3,5-DNSA was prepared in aqueous 1.0 N NaOH. A stock solution of glucose was prepared by adding 3.6032 g to a 100-ml volumetric flask which was filled to volume with distilled water. Two and one-half milliliters of the 3,5-DNSA solution and 0.01 milliliters of the glucose solution were pipetted into a 10-ml volumetric flask and mixed. The flask was placed in a boiling water bath for 10 minutes, cooled, and filled to volume with distilled water. Polarographic analysis was performed as previously described. The above procedure was similarly performed with 3,5-DNSA blank solutions and also in the presence of larger volumes of glucose to evaluate glucose: 3,5-DNSA molar ratios ranging between 1:1 and 10:1. The ΔI d was calculated for each test solution (Table III). The ΔI d results were plotted versus the glucose: 3,5-DNSA molar ratio (FIG. 3). TABLE III______________________________________Effect of Glucose Concentration on the DiffusionCurrent of the 3,5-DNSA Reduction Wave Change in Diffusion CurrentGlucose/3,5-DNSA Ratio (ΔI.sub.d in μA)______________________________________0 01 0.622 1.273 1.844 2.155 2.426 2.647 2.878 2.9110 2.98______________________________________ Reaction of Glucose with 3,5-Dinitrosalicylic Acid in 3.0 N NaOH Five milliliters of a stock 3,5-dinitrosalicylic acid solution, 8×10 -4 M 3,5-DNSA in 0.6 N NaOH, and 4.5 ml of 6.0 N NaOH, were pipetted into a 10-ml volumetric flask. A volume of 0.01 milliliters of an aqueous 8×10 -2 M glucose standard was added and the flask was filled to the mark with distilled water. The solution was mixed and polarographic analysis was performed as previously described. Blank solutions and working standards were similarly prepared and analysed to evaluate glucose: 3,5-DNSA molar ratios between 0:1 and 2:1 in increments of 0.2. The ΔI d results were calculated and plotted versus the glucose: 3,5-DNSA molar ratio (Table IV and FIG. 4). TABLE IV______________________________________Effect of Glucose on the Diffusion Current ofthe 3,5-DNSA Reduction Wave Change in Diffusion CurrentGlucose/3,5-DNSA Ratio (ΔI.sub.d in μA)______________________________________0 00.2 0.240.4 0.550.6 0.670.8 1.101.0 1.241.2 1.731.4 2.171.6 2.402.0 2.99______________________________________ The Effect of Base Concentration on the Reactivity of Glucose with 3,5-Dinitrobenzoic Acid A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 17.0 mg of 3,5-DNBA and 16.7 mililiters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water. A stock solution of glucose was prepared by adding 762.7 mg to a 50-ml volumetric flask which was filled to volume with distilled water. A test solution was prepared by adding 5 milliliters of the 3,5-DNBA solution, 0.1 milliliters of the glucose solution, and 0.83 milliliters of 6 N NaOH to a 10-ml volumetric flask which was filled to volume with distilled water. The final NaOH concentration was 1.0 N. The test solution was mixed and placed into a boiling water bath for 5 minutes. The solution was cooled to room temperature and polarographic analysis was performed as previously described. The above procedure was similarly performed for test solutions containing final NaOH concentrations of 1.5, 2.0, 2.5, 3.0, and 3.5 N. Blank solutions were similarly prepared and tested for each base concentration studied. The difference in diffusion current (ΔI d ) was calculated for each of the corresponding blank and test results (Table V). The ΔI d results were plotted versus the concentration of NaOH (FIG. 5). TABLE V______________________________________Effect of Base Concentration on the DiffusionCurrent of the 3,5-DNBA-Glucose ReactionFinal NaOH Change inConcentration Diffusion Current(N) (ΔI.sub.d in μA)______________________________________1.0 0.671.5 1.102.0 1.202.5 2.083.0 2.643.5 3.21______________________________________ Reaction of Glucose with 3,5-Dinitrobenzoic Acid in 0.75 N NaOH An 8.0×10 -4 M stock solution of 3,5-dinitrobenzoic acid was prepared in aqueous 1.0 N NaOH. A test solution was prepared by adding 5.0 milliliters of 3,5-DNBA solution, 10 μl of a 0.2 M glucose solution, and 1.25 milliliters of 2.0 N NaOH to a 10-ml volumetric flask. The glucose: 3,5-DNBA molar ratio was 0.5:1. The solution was mixed, incubated in a boiling water bath for 5 minutes, cooled, and brought to volume with distilled water. Polarographic analysis was performed as previously described. A blank was similarly prepared and tested in the absence of glucose. The above procedure was similarly performed for glucose and 3,5-DNBA at molar ratios of 1:1 and 1.5:1. The diffusion current was calculated for each test solution and the results were plotted versus the Glucose: 3,5-DNBA molar ratio (Table Vi and FIG. 6). TABLE VI______________________________________Effect of Glucose on the Diffusion Currentof the 3,5-DNBA Reduction Waves Diffusion CurrentGlucose/3,5-DNBA (μA)______________________________________0 4.740.5 4.021.0 2.831.5 1.57______________________________________ Analysis of Glucose in Biological Fluids Glucose in Serum A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 8.5 mg of 3,5-DNBA and 10.0 milliliters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water. One milliliter of "normal" serum was deproteinized by adding 1.0 milliliter of trichloroacetic acid, mixing the solution vigorously, and centrifuging. Five milliliters of 3,5-DNBA solution, 0.1 milliliters of deproteinized serum, and 4.5 milliliters of 6 N NaOH were added to a 10-ml volumetric flask. The flask was filled to the mark with distilled water, mixed, and placed in a boiling water bath for 5 minutes. The test solution was brought to room temperature and polarographic analysis was performed as previously described. The above procedure was similarly performed for four aliquots for serum containing standard additions of glucose at 50, 100, 140, and 200 mg/100 ml of serum. The total diffusion current for the nitro group reduction waves was recorded for each test solution (Table VII). The I d results were plotted versus the quantity of glucose added (FIG. 7). TABLE VII______________________________________Effect of Deproteinized Serum and Glucose Standard Additionson the Diffusion Current of the 3,5-DNBA Composite WaveGlucose Addition Diffusion Current(mg/100 ml) (μA)______________________________________0 14.050 13.0100 11.5140 10.9200 9.5______________________________________ Glucose in Urine A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 8.5 mg of 3,5-DNBA and 10.0 milliliters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water. Five milliliters of the 3,5-DNBA solution, 50 μl of "normal" urine, and 4.5 milliliters of 6 N NaOH were added to a 10-ml volumetric flask. The flask was filled to the mark, mixed, and placed in a boiling water bath for 5 minutes. The test solution was brought to room temperature and polarographic analysis was performed as previously described. The above procedure was similarly performed for three aliquots of urine containing standard additions of glucose at 20, 50, and 100 mg/100 ml of urine. The total diffusion current for the nitro group reduction waves were recorded for each test solution (Table VIII). The I d results were plotted versus the quantity of glucose added (FIG. 8). TABLE VIII______________________________________Effect of Urine and Glucose Standard Additions onthe Total Diffusion Current of the 3,5-DNBA WavesGlucose Addition Diffusion Current(mg/100 ml) (μA)______________________________________ 0 1.4620 1.2050 0.75100 0.50______________________________________ The addition of sodium chloride to the test solution has improved the overall appearance of the nitro reduction waves. Optimal improvement is noted for aromatic compounds containing two or three nitro groups. The usually difficult to measure second and third nitro reduction waves are well defined and can easily be measured. REFERENCES 1. Meur, S. K., Rao, V. S., De, K. B., Spectrophotometric Estimation of Reducing Sugars by Variation of pH. Fresenius Z. Anal. Chem. 283, 195 (1977) 2. Gindler, E. M., Determination of Amylase. U.S. Pat. No. 3,953,297 (Apr. 1976). 3. Gindler, E. M., Determination of Amylase. U.S. Pat. No. 3,869,348 (Mar. 1975). 4. Van Bezeij, M., and Bosch, M. W., An Unequivocal Method for Blood Sugar Determination Using Dinitrosalicylic Acid as the Color Reagent. Pharm. Weekbl. 111,505 (1976) 5. Scholze, D., Rapid Method for the Analysis of Reducing Substances in Beet Pulp. Lebensm.-Ing. 21,255 (1974) 6. Bittman, R., Analysis of Reducing Sugars in Breakfast Cereal and Other Foods. J. of Chem. Educ. 51,46 (1974) 7. Amador, E., Automated Urinary Glucose Analyses. Am. J. Clin. Path. 59, 735 (1973) 8. Searcy, R. L., Hayashi, S., and Berk, J. E., A New Micro Saccharogenic Method for Serum Amylase Determination. Am. J. Clin. Path. 46, 582 (1966) 9. Fingerhut, B., Ferzola, R., Poock, A., and Marsh, W. H., A Rapid Saccharogenic Method for the Determination of Serum Amylase. Clin. Chem. 11, 862 (1965) 10. Henry, R. J., and Chiamori, N., Study of the Saccharogenic Method for the Determination of Serum and Urine Amylase. Clin. Chem. 5, 434 (1960) 11. Kozlov, V. V., and Khrustaleva, V. M., Colorimetric Method of Determination of Carbohydrates with Dinitrosalicylic Acid. Sbornik Nauch. Prabot. Moskov. Inst. Narod. Khoz. 10, 353 (1957) 12. Bell, D. J., Manners, D. J., and Palmer, A., Observations on the Reaction of Alkaline 3,5-Dinitrosalicylate by Certain Carbohydrates. J. Chem. Soc. London. 3760 (1952). 13. Hostettler, F., Borel, E., and Deuel, H., Uber die Reduktion 3,5-Dinitrosalicylsaure durch Zucker. Helv. Chim. Acta. 34, 2132 (1951) 14. Brodersen, R., and Ricketts, T., Evaluation of a Modified Sumner's Method (Dinitrosalicylic Acid) for Determination of Glucose in Urine. J. Lab. Clin. Med. 34, 1447 (1949). 15. Leech, R. S., and Woodford, N., A Simple Bedside Method for the Estimation of Blood Sugar. J. Lab. & Clin. Med. 33, 644 (1948) 16. Sumner, J. B., and Sisler, E. B., A Simple Method for Blood Sugar. Arch. Biochem. 4, 333 (1944) 17. Short, J. J., Note on the Sumner Method for Sugar in Urine. J. Lab. & Clin. 18, 641 (1933) 18. Sumner, J. B., A More Specific Reagent for the Determination of Sugar in Urine. J. Biol. Chem. 65, 393 (1925) 19. Sumner, J. B., The Estimation of Sugar in Diabetic Urine, Using Dinitrosalicylic Acid. J. Biol. Chem. 62, 287 (1924). 20. Sumner, J. B., Dinitrosalicylic Acid: A Reagent for the Estimation of Sugar in Normal and Diabetic Urine. J. Biol. Chem. 47, 5 (1921)
A method is disclosed for determining glucose whereby glucose is reacted with an aromatic reagent containing one or more nitro groups and the reaction is monitored at electrodes which measure the current produced by the reduction of one or more of the nitro groups.
Summarize the information, clearly outlining the challenges and proposed solutions.
[ "BACKGROUND OF THE INVENTION This invention relates to new and useful improvements in electrochemical detection procedures for the determination of glucose in biological fluids.", "The determination of glucose in biological fluids is probably the most requested laboratory test.", "Glucose measurements are commonly performed on whole blood, serum, urine and cerebrospinal fluid samples.", "Carbohydrate production is affected in numerous physiological and pathological conditions.", "For example, elevations of blood glucose have been observed in pancreatic disease, severe thyrotoxicosis, diabetes Mellitus, Phaeochromocytoma, pituitary and adrenal disorders, etc.", "Similarly, decreases of blood glucose have been observed in pancreatic islet cell hyperplasia, insulin overdosage, adrenal cortical insufficiency, hypopituitarism, acute infections, liver disease, poisonings and the like.", "Colorimetric procedures employing 3,5-dinitrosalicyclic acid (3,5-DNSA) for the determination of glucose and other reducing substances are well documented throughout the chemical literature (see Refs.", "1-20).", "Furthermore, specificity for glucose is claimed (Refs.", "4,7,14) and attributed to the physiologic context in which the method is employed (Ref.", "7).", "Modified colorimetric procedures have been developed for the analysis of reducing sugars in blood (Refs.", "4, 15,16), urine (Refs.", "7,14,16-19) and for a variety of nutrients (Refs.", "5,6,11) e.g. beet pulp, oatmeal cereal, milk, strawberries, vegetables and the like.", "Automated procedures are described for routine blood (Ref.", "4) and urine (Ref.", "7) sugar analyses.", "Recently, saccharogenic detection systems have been adapted to determine serum (Refs.", "2,8-10), and urine (Ref.", "10) amylase.", "These saccharogenic amylase methods are reported to be superior to conventional iodometric procedures (Ref.", "8).", "SUMMARY OF THE INVENTION The process described herein may be employed to determine the concentration of glucose in serum samples.", "Modified procedures employing the same principle may similarly be developed to measure glucose in other fluids or solids brought into solution.", "The process, with or without modification, may be adapted to polarographic and other electrochemical apparatus currently available, or specific analyzers may more economically be built to monitor the decrease of the functional nitro group or groups contained in the reagent employed e.g. 2,4-DNP, 3,5-DNSA, 3,5-DNBA, or other aromatic nitro containing compound.", "The quantitative detection procedure described herein for the electrochemical determination of glucose and other reducing substances is nitro reaction group specific and more sensitive than previously reported colorimetric procedures.", "Chromogenic and turbidimetric interferences are eliminated due to the nature of the detection system.", "In accordance with the invention there is provided a process for the electrochemical determination of the concentration of glucose in a sample of serum, other fluid or solid brought into solution;", "whereby, the sample is reacted at elevated temperatures in an alkaline medium containing an aromatic reagent with one or more attached nitro groups.", "The resulting chemical changes, which the reactive nitro group or groups have undergone, are monitored by electrodes in terms of current changes and the glucose concentration of the sample is established by conventional techniques such as calibration curves, standard addition process, and the like.", "In the analyses included herein by way of examples, the following chemicals were obtained from Fisher Scientific Co., Fair Lawn, N.J.: Fisher Certified anhydrous D-glucose, sodium hydroxide, sodium chloride, 3,5-dinitrobenzoic acid (3,5-DNBA) and reagent grade 2,4-dinitrophenol (2,4-DNP).", "Reagent grade 3,5-dinitrosalicylic acid was purchased from the Eastman Kodak Co., Rochester, N.Y. Triple distilled mercury was obtained from Engelhard Industries of Canada, Ltd., Toronto, Ontario.", "Certified quality nitrogen was supplied by Canadian Liquid Air, Ltd", "However other sources of chemicals can of course be used.", "All analyses were performed in a 10-ml Heyrovsky polarographic cell.", "A dropping mercury electrode (DME) was the indicator electrode and a mercury pool served as the reference electrode.", "The characteristics of the capillary used were: m=0.596 mg s -1 , t=1s, m 2/3 t 1/6 =0.708 mg 2/3 x 1/2 for a drop time setting of 1 second, and m=0.566 mg s -1 , t=2 s, m 2/3 t 1/6 =0.767 mg 2/3 s 1/2 for a drop-time setting of 2 seconds.", "Polarographic analysis was performed with a Model 170 Electrochemistry System from the Princeton Applied Research Corporation, Princeton, N.J., U.S.A. The above data are for reference purposes only.", "With the foregoing in view, and other advantages as will become apparent to those skilled in the art to which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of a typical embodiment of the principles of the present invention, in which: DESCRIPTION OF THE DRAWINGS FIG. 1 is a plot showing the diffusion current results of the reaction of glucose with 2,4-Dinitrophenol plotted versus the glucose: 2,4-DNP ratio.", "FIG. 2 is a plot of the difference in diffusion current of the effect of base concentration on the reactivity of glucose with 3,5-Dinitrosalicylic Acid, plotted versus the concentration of NaOH.", "FIG. 3 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrosalicylic acid in 0.25 N NaOH, plotted versus the glucose: 3,5-DNSA molar ratio.", "FIG. 4 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrosalicylic acid in 3.0 N NaOH, plotted versus the glucose: 3,5-DNSA molar ratio.", "FIG. 5 is a plot of the difference in diffusion current of the effect of base concentration of the reactivity of glucose with 3,5-Dinitrobenzoic acid, plotted versus the concentration of NaOH.", "FIG. 6 is a plot of the difference in diffusion current of the reaction of glucose with 3,5-Dinitrobenzoic acid in 0.75 N NaOH, plotted versus the glucose: 3,5-DNBA molar ratio.", "FIG. 7 is a plot of the total diffusion current for the nitro group reduction waves plotted versus the quantity of glucose added to glucose in serum.", "FIG. 8 is a plot of the total diffusion current for the nitro group reduction waves plotted versus the quantity of glucose added to glucose in urine.", "In the drawings like characters of reference indicate corresponding parts in the different figures.", "DETAILED DESCRIPTION Proceeding therefore to describe the invention in detail, the following methods were used in preparing the necessary standards: Reaction of Glucose with 2,4-Dinitrophenol Fourteen milligrams of 2,4-dinitrophenol and 25 milliliters of 1.0 N NaOH were added to a 50-ml volumetric flask which was brought to volume with distilled water.", "This produced a 1.5×10 -3 M 2,4-DNP stock standard.", "A 7.5×10 -2 M glucose solution was prepared by adding 1.3512 g of glucose to a 100-ml volumetric flask which was brought to volume with distilled water.", "Twenty microliters of the glucose solution and 2.5 milliliters of the 2,4-dinitrophenol stock were pipetted into a 10-ml volumetric flask using a Gilford automatic pipetter/diluter.", "This resulted in a glucose: 2,4-DNP molar ratio of 0.4.", "The solution was mixed, heated in a boiling water bath for 5 minutes, cooled, and brought to volume with distilled water.", "Five milliliters were transferred into a 10-ml volumetric flask.", "Two and a half milliliters of 1.0 N NaOH were added and the flask was mixed and brought to volume with distilled water.", "This working standard was transferred into a 10-ml Heyrovsky cell which contained a small pool of mercury on the floor of the cell to act as the anodic reference electrode.", "The Heyrovsky cell was placed under a dropping mercury electrode onto which a drop timer was attached.", "The mercury reservoir was raised to a height of 59.0 cm.", "Polarograms were recorded throughout the voltage range of -0.3 to -1.75 volts.", "A series of working standards was similarly prepared by increasing the glucose concentration to produce molar ratios between 0.4:1 and 2:1 in increments of 0.4.", "All working standards and appropriate reagent blanks were tested as described above.", "The total diffusion current for the first and second nitro group reduction waves was determined by measuring the vertical distance from the residual current to the limiting current.", "The diffusion current results were plotted versus the glucose: 2,4-DNP ratio (Table I and FIG. 1).", "TABLE I______________________________________Effect of Glucose Concentration on the Total DiffusionCurrent of the 2,4-DNP Reduction Waves Total Diffusion CurrentGlucose/2,4-DNP Ratio (μA)______________________________________0 6.570.4 6.140.8 5.871.2 5.541.6 4.922.0 4.57______________________________________ The Effect of Base Concentration on the Reactivity of Glucose with 3,5-Dinitrosalicylic Acid Five milliliters of a stock solution of 3,5-dinitrosalicylic acid, 8×10 -4 M 3,5-DNSA in 0.6 N NaOH, were transferred to a 10-ml volumetric flask.", "A volume of 0.1 ml of an aqueous 4×10 -2 M glucose standard was added and the solution was mixed.", "The flask was placed in a boiling water bath for five minutes, cooled, and brought to volume with distilled water.", "Polarographic analysis was performed as previously described.", "A blank test was similarly performed in the absence of glucose.", "The difference in the diffusion current (ΔI d ) was calculated from the blank and test results (Table II).", "The above testing process was similarly performed for solutions containing NaOH at the following final molar concentrations: 1.0, 1.5, 2.0, 2.5, and 3.0.", "The ΔI d results were plotted versus the concentration of NaOH (FIG.", "2).", "TABLE II______________________________________Effect of Base Concentration on the DiffusionCurrent of the 3,5-DNSA-Glucose ReactionFinal NaOH Change inConcentration Diffusion Current(N) (ΔI.", "sub.", "d in μA)______________________________________0.3 0.551.0 1.281.5 1.502.0 1.422.5 1.593.0 1.79______________________________________ Reaction of Glucose with 3,5-Dinitrosalicylic acid in 0.25 N NaOH An 8.0×10 -4 M stock solution of 3,5-DNSA was prepared in aqueous 1.0 N NaOH.", "A stock solution of glucose was prepared by adding 3.6032 g to a 100-ml volumetric flask which was filled to volume with distilled water.", "Two and one-half milliliters of the 3,5-DNSA solution and 0.01 milliliters of the glucose solution were pipetted into a 10-ml volumetric flask and mixed.", "The flask was placed in a boiling water bath for 10 minutes, cooled, and filled to volume with distilled water.", "Polarographic analysis was performed as previously described.", "The above procedure was similarly performed with 3,5-DNSA blank solutions and also in the presence of larger volumes of glucose to evaluate glucose: 3,5-DNSA molar ratios ranging between 1:1 and 10:1.", "The ΔI d was calculated for each test solution (Table III).", "The ΔI d results were plotted versus the glucose: 3,5-DNSA molar ratio (FIG.", "3).", "TABLE III______________________________________Effect of Glucose Concentration on the DiffusionCurrent of the 3,5-DNSA Reduction Wave Change in Diffusion CurrentGlucose/3,5-DNSA Ratio (ΔI.", "sub.", "d in μA)______________________________________0 01 0.622 1.273 1.844 2.155 2.426 2.647 2.878 2.9110 2.98______________________________________ Reaction of Glucose with 3,5-Dinitrosalicylic Acid in 3.0 N NaOH Five milliliters of a stock 3,5-dinitrosalicylic acid solution, 8×10 -4 M 3,5-DNSA in 0.6 N NaOH, and 4.5 ml of 6.0 N NaOH, were pipetted into a 10-ml volumetric flask.", "A volume of 0.01 milliliters of an aqueous 8×10 -2 M glucose standard was added and the flask was filled to the mark with distilled water.", "The solution was mixed and polarographic analysis was performed as previously described.", "Blank solutions and working standards were similarly prepared and analysed to evaluate glucose: 3,5-DNSA molar ratios between 0:1 and 2:1 in increments of 0.2.", "The ΔI d results were calculated and plotted versus the glucose: 3,5-DNSA molar ratio (Table IV and FIG. 4).", "TABLE IV______________________________________Effect of Glucose on the Diffusion Current ofthe 3,5-DNSA Reduction Wave Change in Diffusion CurrentGlucose/3,5-DNSA Ratio (ΔI.", "sub.", "d in μA)______________________________________0 00.2 0.240.4 0.550.6 0.670.8 1.101.0 1.241.2 1.731.4 2.171.6 2.402.0 2.99______________________________________ The Effect of Base Concentration on the Reactivity of Glucose with 3,5-Dinitrobenzoic Acid A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 17.0 mg of 3,5-DNBA and 16.7 mililiters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water.", "A stock solution of glucose was prepared by adding 762.7 mg to a 50-ml volumetric flask which was filled to volume with distilled water.", "A test solution was prepared by adding 5 milliliters of the 3,5-DNBA solution, 0.1 milliliters of the glucose solution, and 0.83 milliliters of 6 N NaOH to a 10-ml volumetric flask which was filled to volume with distilled water.", "The final NaOH concentration was 1.0 N. The test solution was mixed and placed into a boiling water bath for 5 minutes.", "The solution was cooled to room temperature and polarographic analysis was performed as previously described.", "The above procedure was similarly performed for test solutions containing final NaOH concentrations of 1.5, 2.0, 2.5, 3.0, and 3.5 N. Blank solutions were similarly prepared and tested for each base concentration studied.", "The difference in diffusion current (ΔI d ) was calculated for each of the corresponding blank and test results (Table V).", "The ΔI d results were plotted versus the concentration of NaOH (FIG.", "5).", "TABLE V______________________________________Effect of Base Concentration on the DiffusionCurrent of the 3,5-DNBA-Glucose ReactionFinal NaOH Change inConcentration Diffusion Current(N) (ΔI.", "sub.", "d in μA)______________________________________1.0 0.671.5 1.102.0 1.202.5 2.083.0 2.643.5 3.21______________________________________ Reaction of Glucose with 3,5-Dinitrobenzoic Acid in 0.75 N NaOH An 8.0×10 -4 M stock solution of 3,5-dinitrobenzoic acid was prepared in aqueous 1.0 N NaOH.", "A test solution was prepared by adding 5.0 milliliters of 3,5-DNBA solution, 10 μl of a 0.2 M glucose solution, and 1.25 milliliters of 2.0 N NaOH to a 10-ml volumetric flask.", "The glucose: 3,5-DNBA molar ratio was 0.5:1.", "The solution was mixed, incubated in a boiling water bath for 5 minutes, cooled, and brought to volume with distilled water.", "Polarographic analysis was performed as previously described.", "A blank was similarly prepared and tested in the absence of glucose.", "The above procedure was similarly performed for glucose and 3,5-DNBA at molar ratios of 1:1 and 1.5:1.", "The diffusion current was calculated for each test solution and the results were plotted versus the Glucose: 3,5-DNBA molar ratio (Table Vi and FIG. 6).", "TABLE VI______________________________________Effect of Glucose on the Diffusion Currentof the 3,5-DNBA Reduction Waves Diffusion CurrentGlucose/3,5-DNBA (μA)______________________________________0 4.740.5 4.021.0 2.831.5 1.57______________________________________ Analysis of Glucose in Biological Fluids Glucose in Serum A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 8.5 mg of 3,5-DNBA and 10.0 milliliters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water.", "One milliliter of "normal"", "serum was deproteinized by adding 1.0 milliliter of trichloroacetic acid, mixing the solution vigorously, and centrifuging.", "Five milliliters of 3,5-DNBA solution, 0.1 milliliters of deproteinized serum, and 4.5 milliliters of 6 N NaOH were added to a 10-ml volumetric flask.", "The flask was filled to the mark with distilled water, mixed, and placed in a boiling water bath for 5 minutes.", "The test solution was brought to room temperature and polarographic analysis was performed as previously described.", "The above procedure was similarly performed for four aliquots for serum containing standard additions of glucose at 50, 100, 140, and 200 mg/100 ml of serum.", "The total diffusion current for the nitro group reduction waves was recorded for each test solution (Table VII).", "The I d results were plotted versus the quantity of glucose added (FIG.", "7).", "TABLE VII______________________________________Effect of Deproteinized Serum and Glucose Standard Additionson the Diffusion Current of the 3,5-DNBA Composite WaveGlucose Addition Diffusion Current(mg/100 ml) (μA)______________________________________0 14.050 13.0100 11.5140 10.9200 9.5______________________________________ Glucose in Urine A stock solution of 3,5-dinitrobenzoic acid was prepared by adding 8.5 mg of 3,5-DNBA and 10.0 milliliters of 6 N NaOH to a 100-ml volumetric flask which was filled to the mark with distilled water.", "Five milliliters of the 3,5-DNBA solution, 50 μl of "normal"", "urine, and 4.5 milliliters of 6 N NaOH were added to a 10-ml volumetric flask.", "The flask was filled to the mark, mixed, and placed in a boiling water bath for 5 minutes.", "The test solution was brought to room temperature and polarographic analysis was performed as previously described.", "The above procedure was similarly performed for three aliquots of urine containing standard additions of glucose at 20, 50, and 100 mg/100 ml of urine.", "The total diffusion current for the nitro group reduction waves were recorded for each test solution (Table VIII).", "The I d results were plotted versus the quantity of glucose added (FIG.", "8).", "TABLE VIII______________________________________Effect of Urine and Glucose Standard Additions onthe Total Diffusion Current of the 3,5-DNBA WavesGlucose Addition Diffusion Current(mg/100 ml) (μA)______________________________________ 0 1.4620 1.2050 0.75100 0.50______________________________________ The addition of sodium chloride to the test solution has improved the overall appearance of the nitro reduction waves.", "Optimal improvement is noted for aromatic compounds containing two or three nitro groups.", "The usually difficult to measure second and third nitro reduction waves are well defined and can easily be measured.", "REFERENCES 1.", "Meur, S. K., Rao, V. S., De, K. B., Spectrophotometric Estimation of Reducing Sugars by Variation of pH.", "Fresenius Z. Anal.", "Chem.", "283, 195 (1977) 2.", "Gindler, E. M., Determination of Amylase.", "U.S. Pat. No. 3,953,297 (Apr. 1976).", "Gindler, E. M., Determination of Amylase.", "U.S. Pat. No. 3,869,348 (Mar. 1975).", "Van Bezeij, M., and Bosch, M. W., An Unequivocal Method for Blood Sugar Determination Using Dinitrosalicylic Acid as the Color Reagent.", "Pharm.", "Weekbl.", "111,505 (1976) 5.", "Scholze, D., Rapid Method for the Analysis of Reducing Substances in Beet Pulp.", "Lebensm.", "-Ing.", "21,255 (1974) 6.", "Bittman, R., Analysis of Reducing Sugars in Breakfast Cereal and Other Foods.", "J. of Chem.", "Educ.", "51,46 (1974) 7.", "Amador, E., Automated Urinary Glucose Analyses.", "Am.", "J. Clin.", "Path.", "59, 735 (1973) 8.", "Searcy, R. L., Hayashi, S., and Berk, J. E., A New Micro Saccharogenic Method for Serum Amylase Determination.", "Am.", "J. Clin.", "Path.", "46, 582 (1966) 9.", "Fingerhut, B., Ferzola, R., Poock, A., and Marsh, W. H., A Rapid Saccharogenic Method for the Determination of Serum Amylase.", "Clin.", "Chem.", "11, 862 (1965) 10.", "Henry, R. J., and Chiamori, N., Study of the Saccharogenic Method for the Determination of Serum and Urine Amylase.", "Clin.", "Chem.", "5, 434 (1960) 11.", "Kozlov, V. V., and Khrustaleva, V. M., Colorimetric Method of Determination of Carbohydrates with Dinitrosalicylic Acid.", "Sbornik Nauch.", "Prabot.", "Moskov.", "Inst.", "Narod.", "Khoz.", "10, 353 (1957) 12.", "Bell, D. J., Manners, D. J., and Palmer, A., Observations on the Reaction of Alkaline 3,5-Dinitrosalicylate by Certain Carbohydrates.", "J. Chem.", "Soc.", "London.", "3760 (1952).", "13.", "Hostettler, F., Borel, E., and Deuel, H., Uber die Reduktion 3,5-Dinitrosalicylsaure durch Zucker.", "Helv.", "Chim.", "Acta.", "34, 2132 (1951) 14.", "Brodersen, R., and Ricketts, T., Evaluation of a Modified Sumner's Method (Dinitrosalicylic Acid) for Determination of Glucose in Urine.", "J. Lab.", "Clin.", "Med.", "34, 1447 (1949).", "15.", "Leech, R. S., and Woodford, N., A Simple Bedside Method for the Estimation of Blood Sugar.", "J. Lab.", "&", "Clin.", "Med.", "33, 644 (1948) 16.", "Sumner, J. B., and Sisler, E. B., A Simple Method for Blood Sugar.", "Arch.", "Biochem.", "4, 333 (1944) 17.", "Short, J. J., Note on the Sumner Method for Sugar in Urine.", "J. Lab.", "&", "Clin.", "18, 641 (1933) 18.", "Sumner, J. B., A More Specific Reagent for the Determination of Sugar in Urine.", "J. Biol.", "Chem.", "65, 393 (1925) 19.", "Sumner, J. B., The Estimation of Sugar in Diabetic Urine, Using Dinitrosalicylic Acid.", "J. Biol.", "Chem.", "62, 287 (1924).", "20.", "Sumner, J. B., Dinitrosalicylic Acid: A Reagent for the Estimation of Sugar in Normal and Diabetic Urine.", "J. Biol.", "Chem.", "47, 5 (1921)" ]
BACKGROUND OF THE INVENTION This invention relates to an image forming apparatus such as a copying machine and a laser beam printer. The sensitivity characteristics of a photosensitive member vary with time or variations of environmental conditions such as temperature and humidity. To make up for such variations, it has been proposed to measure the sensitivity characteristic of photosensitive medium by the provision of a sensor, control the surface status of a photosensitive drum by varying the corona charger grid voltage or exposure energy at the time of exposure to image through comparison with the measured characteristic and control the output image density to be constant by varying image forming conditions in accordance with detected temperature or humidity by further adding temperature and/or humidity sensor means to the image forming apparatus. FIG. 36 shows a prior art example of setting the conditions for image forming through control of the corona charger grid voltage and setting optimum conditions through switching the amount of exposure to laser beam between two levels when a forming condition range exceeds a grid voltage range. This method is for controlling the photosensitive drum surface potential contrast as image forming condition. In this case, under a constant exposure amount condition, the grid bias is varied continuously, thus varying surface potential V D on the photosensitive medium to vary the grid bias for obtaining desired potential contrast V D -V L . However, where the desired potential contrast range is broad, a sufficiently broad variation range can not be obtained with a single exposure amount. For this reason, it is proposed to permit switching of the exposure amount between levels for high and low potential contrast ranges as shown in FIG. 37. More specifically, when the potential contrast exceeds point B, the exposure amount is switched from level Lo to level Hi. In this case of exposure amount switching, the potential contrast control is performed such that the grid bias is varied with the exposure amount to obtain the same potential contrast B and B', as shown in FIG. 36. With this method, the potential contrast is controlled from A through B and B' to C in a case where it is varied in the increasing direction, while it is controlled from C through B' and B to A when it is varied in the reducing direction. In this way, it is possible to control the potential contrast over a wide range. However, the sensitivity characteristic of photosensitive media varies with individual media. In addition, even with photosensitive medium having identical sensitivity charactetistic, there are liable to characteristic variations because of fluctuations of current characteristics of laser in exposure system and optical efficiency of optical system depending on the image forming apparatus. With the prior art example noted above, although it is possible to make up for variations with time, it is impossible to make up for initial fluctuations of the sensitivity characteristic of photosensitive medium. For example, the relation between surface potential and grid bias voltage shown in FIG. 36 corresponds to either V D1 and V L1 or V D2 and V L2 , as shown in FIG. 39, depending on the sensitivity characteristic of the photosensitive medium. If there is desired potential contrast D in this case, with a photosensitive medium having characteristics V D1 and V L1 the desired potential contrast can be obtained by setting grid bias voltage V G2 , but with photosensitive medium with characteristics V D1 and V D2 it can not be obtained with initial preset light amount L 0 (it being assumed that D<B). In such prior art example, even if the potential contrast is controlled to be equal at the time of switching of the exposure amount in a potential contrast range subject to the exposure amount switching, i.e., between B and B' in FIG. 36, the image quality, particularly the gradation, is subject to variations between points B and B' because of the influence of the V-E characteristic (i.e., relation between surface potential and exposure amount) accompanying the switching of the exposure amount. More specifically, FIG. 38A shows V-E characteristic of a typical photosensitive medium such as OPC (organic photo-semiconductor). As is seen, in this V-E characteristic the potential is not varied linearly with the exposure amount. Actual V-E characteristic is as shown in FIG. 38B depending on the maximum exposure amount in use. Therefore, in case if photosensitive medium control is carried out by the method noted above such as to obtain potential contrast at point B (B') in FIG. 36, there is a problem that the image quality of the output image is subject to variation when the exposure amount switching is effected with a change in the desired potential contrast due to a slight environmental variation. Heretofore, it has been in practice to effect correction of gradation at the time of such exposure amount switching. However, it has been difficult to stabilize the image quality with correction corresponding to the exposure amount change. Particularly, with a full-color image forming apparatus, in which importance is attached to the gradation, it is necessary to stabilize the gradation. SUMMARY OF THE INVENTION The present invention has been intended in the light of the foregoing, and it has an object of providing an improved image forming apparatus. Another object of the invention is to provide an image forming apparatus, which permits formation of adequate image at all time irrespective of environmental variations and fluctuations of individual apparatuses. A further object of the invention is to provide an image forming apparatus, which permits selection of the sensitivity characteristic of photosensitive medium to be in an optical exposure energy range. A still further object of the invention is to provide an image forming apparatus, which permits multi-level exposure energy switching in an exposure energy range selected according to sensitivity characteristic. A yet further object of the invention is to provide an image forming apparatus, with which a hysteresis characteristic is provided in a switching characteristic when switching the exposure amount according to the sensitivity characteristic of photosensitive medium. A yet another object of the invention is to provide an image forming apparatus, with which an image signal is corrected when switching the exposure amount. The above and other objects will become more apparent from the following description when the same is read with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an image forming apparatus embodying the invention; FIG. 2 is a block diagram showing an image processing unit in FIG. 1 in detail; FIG. 3 is a waveform chart showing signal waveforms appearing in various parts of the image processing unit shown in FIG. 2; FIG. 4 is a graph showing the relation between potential on and exposure amount of a photosensitive medium; FIG. 5 is a graph showing the relation between potential and image signal; FIGS. 6 and 7 are flow charts illustrating control routines according to the invention; FIG. 8 is a schematic representation of a color image forming apparatus as second embodiment of the invention; FIG. 9 is a detailed schematic representation of the color image forming apparatus shown in FIG. 8; FIG. 10 is a flow chart illustrating a control routine for selecting an exposure energy range according to a contrast potential; FIG. 11 is a graph showing an example of exposure energy ranges; FIG. 12 is a schematic representation of a color image forming apparatus as third embodiment of the invention; FIG. 13 is a graph showing the relation between surface potential on a photosensitive drum and grid bias potential of a corona charger; FIG. 14 is a graph showing the relation between exposure amount and necessary potential contrast on a photosensitive drum; FIGS. 15 and 16 are graphs showing the relation between exposure amount and necessary potential contrast on a photosensitive drum for illustrating control operation of the embodiment in case when permitting multi-level switching of the exposure amount; FIG. 17 is a graph showing the relation between exposure amount and necessary potential contrast; FIGS. 18A and 18B are graphs showing the relation between exposure amount and surface potential on photobetween sensitive drum; FIG. 19 is a graph showing the relation between exposure amount and necessary contrast potential in case where a hysteresis characteristic is provided for an exposure amount switching characteristic; FIGS. 20 and 22 are graphs showing the relation between exposure energy range and necessary potential contrast; FIG. 21 is a flow chart illustrating a control operation for selecting an exposure energy range according to a potential contrast; FIG. 23 is a flow chart illustrating a potential control routine; FIG. 24 is a graph showing the relation between surface potential and grid bias voltage of a charger; FIG. 25 is a graph showing the relation between light quantity of laser and pulse width; FIG. 26 is a view showing the relation between laser power and light waveform; FIG. 27 is a sectional view showing a color copier embodying the invention; FIG. 28 is a schematic representation of a laser drive system including a processing block of the same embodiment color copier; FIG. 29 is a block diagram showing a gradation control circuit. FIG. 30 is a block diagram showing a binary encoding circuit; FIGS. 31 and 34 are graphs showing the relation between laser light quantity and video data; FIGS. 32 and 35 are graphs showing contents of LUT in the embodiment; FIG. 33 is a circuit diagram showing a laser driver; and FIGS. 36, 37, 38A, 38B and 39 are graphs for explaining a prior art potential control system. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Now, one embodiment of the invention will be described with reference to the drawings. FIG. 1 is a schematic representation of an image forming apparatus (hereinafter referred to as laser printer) as one embodiment of the invention, FIG. 2 is a block diagram showing an image processing unit shown in FIG. 1, FIG. 3 is a waveform chart showing timings of various signals appearing in various parts of the image processing unit shown in FIG. 2, FIG. 4 is a graph showing a potential versus exposure amount characteristic of a photosensitive medium in the same embodiment, FIG. 5 is a graph showing a potential versus image signal characteristic of the same photosensitive medium, FIG. 6 is a flow chart illustrating a control operation of the same embodiment, and FIG. 7 is a flow chart illustrating a separate control operation of the same embodiment. In FIG. 1, parts like or corresponding to those in the prior art example are designated by like reference numerals and symbols, while omitting their description again. The individual components will first be described. Reference numeral 20 designates an image processing unit, which receives digital image data 22 and reference clock signal 23 and provides binary encoded image data obtained as a result of substantially continuous pulse width modulation according to image density (to be described later in detail). Binary encoded image data 21 is supplied to laser driving unit 24, which controls the laser beam intensity, thus driving laser 4 to produce a modulated laser beam. The laser beam from laser 4, as described before in connection with the prior art example, scans photosensitive medium 1 to form a two-dimensional electrostatic latent image thereon with rotation thereof in the direction of arrow 2. The electrostatic latent image is developed by developing unit 5 to be transferred to transfer sheet 7. Residual tonor without being transferred is collected by cleaner 10. After the transfer, transfer sheet 7 is separated from the photosensitive drum and fed past fixing unit 9 before being discharged. Reference numeral 25 designates a potential sensor, which is located in the proximity of the surface of photosensitive medium 1 at a position after a position of exposure of medium 1 to laser beam and detects the potential of electrostatic latent image on the photosensitive medium surface. The output of potential sensor 25 is supplied to potential measurement unit 26 for measurement of potential. The output of potential sensor 25 is an analog signal and is converted by A/D converter 27 into a digital signal which is supplied to control unit 28. Control unit 28 includes a microcomputer (hereinafter referred to as CPU), a ROM which stores control programs and data of the CPU, a RAM as word area of the CPU, as well as various I/O ports and A/D converters. It controls the entire laser printer and also provides command signals as analog signals to various controlled units to be described later. Reference numeral 29 designates a high voltage control unit for controlling charging current of charger 3, and 30 a high voltage control unit for controlling a grid bias voltage applied to charger 3. Reference numeral 31 designates a developing bias control unit for controlling a developing bias voltage applied to developing unit 5. The operation of the image processing unit shown in FIG. 1 will now be described with reference to FIGS. 2 and 3. FIG. 2 is a block diagram showing the detailed construction of image processing unit 20 shown in FIG. 1, and FIG. 3 shows timings of signals appearing in various parts shown in FIG. 2. Referring to the block diagram of FIG. 2, digital image data 22 is converted by D/A converter 202 into analog image signal 203 to be supplied to one input terminal of comparator 211. Timing signal generator 207 produces pixel clock 204 and screen clock 208 according to reference clock signal 23 supplied to timing signal generator 207 and provides screen clock 208 to pattern signal generator 209 and pixel clock 204 to D/A converter 202. Pattern signal generator 209 produces pattern signal 210 on the basis of screen clock 208, signal 210 being supplied to the other input terminal of comparator 211. Referring to the timing chart of FIG. 3, digital image data 22 is supplied in synchronism to pixel clock 204, and D/A converter 202 supplies analog image signal 203 to one input terminal of comparator 211 in synchronism to pixel clock 204. Screen clock 208 is a clock signal having an integral multiple of the cycle period of pixel clock 204 and defines the cycle period of pattern signal 210, which is, for instance, a triangular wave as shown. Analog image signal 203 and pattern signal 210 supplied to comparator 211 are compared in comparator 211. As a result, binary encoded image data 21 is produced, which is "0" of analog image signal 203 is greater and "1" otherwise. In the case of timings shown in FIG. 3, screen clock 208 has double the cycle period of pixel clock 204. In this case, binary encoded image data 21 has a pulse waveform obtained as a result of pulse modulation according to pattern signal 210 as digital image signal 22 is changes stepwise from 00 (white) to hexadecimal FF (black). Variation of the amplitude of pattern signal 210, which is a triangular wave for instance, permits variation of the relation between the input level of digital image data 22 and pulse width of binary encoded image data 21. Binary encoded image data 21 obtained as a result of pulse width modulation in the above way, is supplied to laser driving unit 24 and converted in unit 24 into a current waveform having a pulse width corresponding to the input data for driving semiconductor laser 4. It will be seen from the above description that the average exposure amount of the photosensitive medium is increased with increasing image signal toward FF (black) and hence increasing semiconductor laser "on" time per pixel. Further, current I on when semiconductor laser 4 shown in FIG. 1 is "on", can be varied according to a command signal from control unit 28. In other words, the laser beam intensity is increased by increasing current I on and is reduced by reducing I on . That is, the average exposure amount of the photosensitive medium is increased with increasing I on , and this means that a desired exposure amount can be obtained through control of the laser beam intensity. Now, the sensitivity of photosensitive medium and output image density characteristic will be described with reference to FIGS. 4 and 5. The relation between the potential or charge on and sensitivity or exposure amount of photosensitive medium 1 (FIG. 1) (i.e., V-E characteristic) varies with individual photosensitive media, and even with identical photosensitive media it varies depending on conditions and time of its use. Further, semiconductor laser drive current and apparent photosensitive medium sensitivity such as image data and photosensitive medium potential vary with variation of current-intensity characteristic of semiconductor laser 4 and transmittivity of focusing optical system. FIG. 4 shows the V-E characteristic of photosensitive medium. The ordinate is taken for the potential, and the abscissa for the exposure amount. Labeled Vd is a potential in the case of absence of exposure. This potential is equal to the initial charging potential by charger 3. With increasing exposure amount the charge is reduced, and hence the absolute value of potential is reduced. This relation is represented by curve Y. While curve Y is linear over a low exposure amount range, it shows saturation in a high exposure amount range. In FIG. 4, the average exposure amount of and potential of the photosensitive medium are respectively P FF and V FF when the digital image signal is FF (black) and are respectively P 00 and V 00 when the image signal is 00 (white). With exposure amount P FF at point A (FIG. 4), potential changes between V 00 and V FF for a corresponding image signal range between 00 (white) and FF (black) are as shown by curve a in FIG. 5. With exposure amount P FF at point B (FIG. 4), the potential versus image signal characteristic is represented by curve b in FIG. 5. As is seen from curves a and b, even if the output density at V 00 and V FF are constant irrespective of P FF , the density varies for intermediate image signals, and curve b has a higher γ value (i.e., tanθ or difference in the vertical direction divided by difference in the horizontal direction) and leads to cruch in a high density range. Further, even with the same exposure amount of P FF , sensitivity variation of individual photosensitive media leads to characteristic variation like that shown in FIG. 5. In this embodiment, the laser drive current is determined such that linearity is approached by variation of the photosensitive medium potential corresponding to exposure amount variation due to variation of the image signal. Now, light amount control will be described on the basis of the photosensitive medium sensitivity and output image density characteristic described above with reference to the flow charts of FIGS. 6 and 7. FIGS. 6 and 7 show flow charts of light amount control routine programs stored in ROM of control unit 28 (FIG. 1). Referring to FIG. 6, when the light amount control is started in step 6a, step 6b is executed, in which photosensitive medium is pre-rotated in the direction of arrow 2 for erasing residual potential. In subsequent step 6c, initial charging current of charger and initial laser drive current are set. In subsequent steps 6d to 6f, potential sensor 25 measures average potentials V FF , V 80 and V 00 of photosensitive medium corresponding to predetermined exposures FF (black), 80 (gray) and 00 (white) among pulse width modulation laser exposures according to binary encoded image data (FIG. 2) obtained in image processing unit 20 from the respective preset laser bean intensities noted above. In subsequent step 6g, shape coefficient K is calculated from measured values of V FF , V 80 and V 00 obtained in steps 6d to 6f. ##EQU1## The value of K represents the ratio of the potential drop for an intermediate image density and maximum potential drop between OO (white) and FF (black). With a usual photosensor, K approaches 0.5 if the potential-exposure characteristic is linear while it approaches unity if the characteristic is non-linear (FIG. 5). Desired value K 0 of the shape coefficient is set to 0.6 to 0.7. In this case, the lower limit is set in order to reduce shape coefficient K so as to obtain linearity while preventing the exposure amount from being set to be excessively small by excessively demanding the linearity. In subsequent steps 6n and 6i, the value of shape coefficient obtained in step 6g is compared to desired value K 0 , for instance 0.6 to 0.7. If the value of K calculated from the measurement is greater than the desired value range, the routine goes to step 6j to reduce the laser drive current to a predetermined extent so as to reduce the laser beam intensity and then goes back to step 6d. If coefficient K is less than the desired value range, the routine goes to step 6k to increase the laser drive current to a predetermined extent and then goes back to step 6d. If it is determined that coefficient K is in the desired value range (i.e., 0.6 to 0.7 in the instant case), it is determined that adequate linearity is obtained, and the routine goes to step 6l to bring an end to the exposure control operation. In the above case, the drive current is changed every time the measurement of V FF , V 80 and V 00 is effected. However, it is possible to obtain the same results through pulse width control. FIG. 7 shows a control flow chart in case of the pulse width control. Referring to FIG. 7, steps 7a to 7c are like respective steps 6a to 6c in FIG. 6. In steps 7d 1 to 7d 16 (i.e., a total of 16 steps), the pulse width for turn-on of laser 4 is changed in each step to effect exposure of photosensitive medium 1, and potential is measured in each step and stored in RAM of control unit 28. For example, in step 7d 1 the pulse width for turn-on of laser 4 is set to 0, and potential V 0 of zero exposure is measure and stored in RAM. Subsequently, the pulse width is increased to a predetermined extent, and in step 7d 2 potential V 16 is measured again. Then, the average exposure amount on the photosensor is set such that it is increased linearly according to the pulse width (FIG. 5). In this way, up to potential V 16 in step 7d 16 is measured and stored in RAM. In subsequent step 7e, the following calculation is performed with respect to potential data V 0 to V 16 stored in RAM. ##EQU2## where n=2, 3, . . . , 26 The value of n is obtained, with which the value of K n is a desired value, for instance 0.6 to 0.7, and preliminarily obtained laser drive current I n is set, with which exposure amount P with n-th pulse width in steps 7d 1 to 7d 16 is equal to maximum exposure amount P FF at the time of actual exposure to image (step 7f). The control operation is ended in step 7g. It is further possible to obtain voltage measurement without pulse width control but by changing the sole laser drive current. As has been shown, with this embodiment it is possible to obtain image output having stable gradation irrespective of photosensitive medium sensitivity changes by determining the potential-exposure characteristic and obtaining an exposure condition such as to approximate a linear characteristic. Now, a different embodiment of the invention will be described, which permits selection of an exposure energy range suited for the characteristic of photosensitive medium and selection of optimum liquid quantity in the selected range. FIG. 8 is a schematic representation of a color copier as this embodiment. Image data 111 provided from a leader unit (not shown) is supplied to gradation control circuit 121 of printer unit 200. Gradation control circuit 121 has a function of synchronizing image clocks of the reader unit and printer unit 200, these clocks having different rates, and also a function of providing for correspondence between image data and color reproduction density of printer unit 200. Output data from gradation control circuit 121 is supplied to laser driver 122 to drive semiconductor laser 123 for image formation. Control unit 125 of printer unit 200, which communicates with the reader unit via communication control line 124, includes control elements of unit 200. Reference numeral 126 designates a potential sensor for detecting charge on photosensitive medium 129, and 127 a potential measurement unit for converting the output from potential sensor 126 into a digital signal which is supplied to control unit 125. Potential data supplied to control unit 125 is read out by CPU 125-1 in control unit 125 to be used for control. A signal from sensor 128 for detecting an image end signal (ITOP) is supplied to control unit 125 for controlling the printing operation. Temperature and humidity sensors 199 and 198 are supplied through A/D converter 125-4 to control unit 125 for compensation for development characteristics. Relative humidity AH is the ratio of steam to saturated steam air at each temperature and is given as ΔH=f(T, H) where T represents the temperature, and H the relative humidity sensor value. The function f is usually expressed as a cubic equation. T and H are provided as outputs of temperature and relative humidity sensors 199 and 198, and these two outputs are A/D converted in A/D converter 125-4 of the control unit for calculation with resultant digital data to obtain the relative humidity. Control for determining the charger grid bias voltage is performed according to the relative humidity thus obtained. In ROM 125-3 operation programs are stored, and RAM 125-4 is used as working area in the operation of CPU 125-1. FIG. 9 shows the construction of FIG. 8 in greater detail. Reference numeral 129 designates an electrophotographic photosensitive drum rotated in the direction of arrow. Photosensitive medium 129 is first uniformly pre-charged by charger 130, and then it is exposed by being scanned with laser beam 131, which is obtained by on-off modulation according to a modulating signal, in a direction perpendicular to the direction of its rotation. As a result, an electrostatic latent image is formed on photosensitive medium 129, and it is then developed by developing unit 132 to obtain a visible image. Although not shown, this embodiment includes four developing units for respective colors Y, M, C and B K . The visible tonor image formed on photosensitive medium 129 is transferred by transfer charger 133 onto transfer medium 134 held on transfer drum 150, and then it is fixed by a fixing unit (not shown). Meanwhile, residual tonor remaining on photosensitive medium 129 after transfer is removed by cleaning unit 135. Subsequently, residual charge remaining on photosensitive medium 129 is removed by removal light from lamp 136. The above sequence of operations is repeated. Digital video signal that is supplied is latched by latch 201 and then supplied to D/A converter 202 for conversion to analog video signal AV which is supplied to one input terminal of comparator 204. To the other input terminal of comparator 204 is supplied triangular wave signal CIS provided from triangular wave generator 205. Comparator 204 compares analog video signal AV and triangular wave signal CIS and provides pulse width modulation signal E, which is supplied to laser driver 122. According to signal E, semiconductor laser 123 is driven to provide laser beam 31, which is produced through on-off modulation according to modulation signal E. Laser beam 131 provided from semiconductor laser 137 is scanned by scanner 138, which may be polygon mirror, galvano-mirror, etc. Reference numeral 139 designates a lens for focusing laser beam 131 as spot on photosensitive medium 129, and 140 a mirror for bending the optical path. Reference numeral 203 designates dynamic range regulation means for regulating the dynamic range of the analog video signal provided in a predetermined check mode from the D/A converter according to signal from CPU 125-1. Reference numeral 208 designates bias regulation means for regulating the triangular wave bias provided in a predetermined check mode from triangular wave generator 205 according to signal from CPU 125-1. Reference numeral 206 designates a selector for selecting signal supplied to D/A converter 202. More specifically, it selects either digital video signal latched in latch 201 or signal from pattern generator 207 according to signal from CPU 125-1. Pattern generator 207 generates data 00 and FF to be used in a laser power processing routine to be described later. A laser power selection process will now be described. FIG. 10 is a flow chart illustrating the control routine for the processing. In the processing, an input "A" selection signal is supplied to selector 206 to drive pattern generator 207 so as to provide a predetermined pattern for reading the surface potential on photosensitive medium 129, and optimum laser power is selected according to the read-out value. The program of this routine is stored in ROM 125-3. Now, the processing will be described with reference to the flow chart. In step S2, "A" input to selector 206 is selected to supply data from pattern generator 207 to D/A converter 202. In step S3, surface potential V 00 on photosensitive medium 129 due to the provided laser beam is read out through potential measurement unit 127 according to data, for instance 00 H , from pattern generator 207. In step S4, surface potential V FF corresponding to hexadecimal data FF H is similarly read out. In steps S3 and S4, equal primary high voltage is provided. In step S5, a check is done as to whether the difference between V 00 and V FF is a predetermined value. If the difference is the predetermined value, preset laser power level P is selected in step S7. If the former is greater than the latter, power level P 1 lower than P 0 is selected in step S8. If the former is less than the latter, power level P 2 higher than P 1 is selected in step S9. Laser power levels P 0 , P 1 , . . . , P n (n being an integer given as n≧0), and the selected power level can be obtained by varying the drive current of the laser driver. A predetermined value of V 00 -V FF is provided such that a desired potential contrast can be obtained by using level P 1 . With the characteristic of photosensitive medium selected in the laser power level selection processing as shown above and with laser power level P 1 selected to P 1 , the laser power level is changed such as P 1 -P 2 →P 3 as the necessary potential contrast is varied with environmental variation. With laser power level P 2 selected in the processing the power level is changed such as P 2 →P 3 →P 4 . . . to attain stabilization of the image density and gradation. FIG. 11 shows an example of power level switching according to the necessary potential contrast. In this instance, n is 7. If either one of power levels P 0 to P 3 is selected in the laser power level selection processing noted above, it means that it means that either one of ranges or areas I to IV is selected depending on the sensitivity characteristic of the pertaining photosensitive medium or optical efficiency of the exposure system or like factors. If the relation between P n and P n-1 is set such that the V-E characteristic (i.e., charging potential versus exposing energy characteristic) of the photosensitive medium is constant, it is possible to eliminate variation of the gradation due to power level switching. The above processing can be carried out when the photosensitive medium or exposure system is replaced or at a certain interval. As is shown, in this embodiment either one of preliminarily provided ranges or areas I to IV is selected in the laser power level selection processing (i.e., steps S5 to S9) depending on whether the value of V 00 -V FF V FF is the same or greater or less than a predetermined value. As an alternative to the above processing, it is possible to have the values of V 00 -V FF and primary high voltage predetermined and permit continuous laser power level such as to regulate V 00 -V FF to a predetermined value using APC (automatic power control), for instance. In this case, once initial P is set, the power level is varied according to the necessary potential contrast while drawing the same curve as the power level curves shown in FIG. 11. As has been shown above, by selecting an adequate exposure energy range for making up for fluctuations of the sensitivity characteristic of the photosensitive medium and optical efficiency of the exposure system it is possible to obtain the necessary potential contrast at all time for attaining image stabilization. Now, a further embodiment will be described, in which a switching characteristic when switching the exposure amount according to the necessary potential contrast is provided with a hysteresis characteristic. FIG. 12 is a schematic representation of a full-color image forming apparatus as embodiment of the invention. Laser control unit 201 produces a laser beam modulated according to an image input signal. Polygon mirror 202 having a plurality of rotary mirror surfaces is rotated at a constant speed by a scanner motor (not shown) for deflecting the incident laser beam. Reference numeral 203 is a focusing lens, which is an optical lens having a f/θ characteristic, and 204 a photosensitive drum as photosensitive medium, which is exposed to incident laser beam to form electrostatic latent image. Photosensitive drum 204 is rotated in the direction of arrow. Reference numeral 205 designates a discharging lamp for discharging the surface of photosensitive drum 204 to provide uniform potential thereon, 206 a corona charger for uniformly charging the surface of photosensitive drum 204, and 207 a grid electrode serving as control electrode when uniformly charging the surface of photosensitive drum 204. Developing means 208a to 206d develope electrostatic latent image formed on photosensitive drum 4 with respective developers (i.e., magenta, cyan, yellow and black developers) according to developing biases applied to respective developing sleeves Sa to Sd. Reference numeral 209 designates a transfer drum carrying a transfer sheet fed from transfer sheet cassette 210, 211 a transfer charger for transferring tonor image formed on photosensitive drum 204 onto the transfer sheet carried by transfer drum 209, 212 a separating pawl for separating transfer sheet after transfer of the individual color tonor images from transfer drum 209, 213 a fixing unit for fixing the tonor image transferred onto the transfer sheet, 214 a discharging tray, on which transfer sheets with fixed tonor images are stacked, 215 a cleaning unit for recovering residual tonor remaining on photosensitive drum 204, 216 a potential sensor provided in the proximity of photosensitive drum 4 at a position after the position of exposure to laser beam and serving to detect the latent image potential, 217 an A/D converter for converting analog output of potential sensor 216 into a digital output, and 218 voltage control unit consisting of a microcomputer including a RAM as data and control data memory means and a CPU as bias calculation means and control means. D/A converter 219 converts control data determined by voltage control unit 218 into analog data and provides control data to high voltage control unit 220a, which controls voltage applied to charger 206, and also to grid bias voltage control unit 220b, which controls grid bias voltage applied to grid electrode 7, and developing bias data to developing bias voltage control circuits 221a to 221d for controlling developing units 208a to 208d. Now, the operation of controlling the surface potential on photosensitive drum 204 will be described with reference to FIGS. 13 and 14. In this embodiment, as in the prior art example, the setting of conditions for image formation is effected through control of the voltage applied to grid electrode 207 of corona charger 206 according to data obtained from potential sensor 216. Further, when a grid voltage control range is exceeded by image formation condition range, i.e., necessary potential contrast V D -V L , the amount of exposure of photosensitive drum 204 to laser beam is switched to change potential V on bright portion of the drum surface (V L (Hi) ←→V L (Lo)), thus permitting a broader potential contrast range to be obtained. (FIG. 13). However, when the exposure amount is switched, the image quality, particularly gradation, is varied due to influence of the V-E characteristic of photosensitive drum 204. Therefore, it is desired to dispense with the exposure amount switching as much as possible. To solve this problem, in this embodiment, as shown in FIG. 14, the exposure amount switching is effected at different potential contrast in case when switching Lo over to Hi and in case when switching Hi over to Lo. More specifically, in this embodiment the switching of the exposure amount from the side of Lo over to the side of Hi is effected when necessary potential contrast V D -V L becomes predetermined value V C (C C'), but the switching from the side of Hi over to the side of Lo is not effected upon reaching of value V but is effected only when lower value V B is reached (B' B). In other words, a hysteresis characteristic is provided to the characteristic of switching of the exposure amount according to necessary potential contrast V D -V L . When obtaining the necessary potential contrast of V C through such control, after switching of the exposure amount from Lo over to Hi the exposure amount is not switched upon reaching of V C by the potential contrast again but is switched when and only when the potential contrast is reduced to V B which is lower than V C . Therefore, even when the potential contrast is varied slightly due to environmental variation, the exposure amount is not switched, thus permitting constant image quality to be maintained. In the above embodiment the exposure amount is switched between two levels, but this is by no means limitative, and the invention is applicable to an apparatus permits switching of more than two levels as well. FIG. 15 is a graph showing exposure amount variation in an apparatus, in which the exposure amount is subject to switching among six levels according to necessary potential contrast V D -V L . By permitting such frequent exposure amount switching, the exposure amount change at the time of switching is reduced to alleviate variation of the regulation property accompanying the V-E characteristic of photosensitive drum 204. On the demerit side, however, the points of switching are increased, and the exposure amount is switched frequently even with slight environmental variations, thus resulting in degradation of the image quality. However, by controlling the exposure amount in the above method such that a hysteresis characteristic is provided at each point of switching as shown in FIG. 16, once the exposure amount is switched, constant exposure amount can be maintained unless a great environmental variation takes place. Therefore, by applying the invention to such apparatus, with which the gradation is subject to less change when switching the exposure amount, it is possible to obtain very high image quality. The above switching of the exposure amount between two levels and among six levels is by no means limitative, and the invention is applicable to an apparatus, in which the exposure amount is switched among any number of different levels. Now, a further embodiment will be described, in which an adequate one of a plurality of exposure energy ranges is selected according to the necessary potential contrast, and the exposure amount is switched among a plurality of levels in the selected exposure energy range with a hysteresis characteristic provided to the switching characteristic. The construction of apparatus of this embodiment is the same as shown in FIG. 12. FIG. 17 is a graph showing exposure amount variation of an apparatus, in which the exposure amount is switched among five levels according to necessary potential contrast V D -V L . With such frequent switching of the exposure amount, the exposure amount change at the time of switching is reduced to alleviate variation of the gradation accompanying changes in the V-E characteristic of photosensitive drum 204 as noted above. The variation of the gradation can be alleviated by reducing the exposure amount change to 20% or below. FIGS. 18A and 18B show V-E characteristic changes in case where the exposure amount is switched among five levels with a change of about 20%. Doing so permits considerable alleviation of the variation of the gradation at the time of switching, as is seen from FIG. 18B. The variation of the gradation at the time of switching can be substantially ignored if the change in the exposure amount is set to 10% or below. While this embodiment has concerned switching of the exposure amount among five levels, this is by no means limitative, and sufficient effects are obtainable so long as the exposure amount can be switched among at least three levels. As shown above, with control of the exposure amount switching such as to provide a hysteresis at each point of switching the frequency of switching can be greatly reduced, and variation of the gradation at the time of switching can be extremely reduced by increasing the number of switching levels and setting the change at each switching to be 20% or below. From the above, if the exposure amount switching is controlled with a hysteresis provided at each point of switching, once the exposure amount is switched a constant exposure can be maintained unless great environmental variation takes place. By applying the invention to such apparatus, in which the gradation is subject to less variation at the time of switching of the exposure amount, therefore, it is possible to obtain very high image quality. Further, this embodiment seeks to attain stabilization of image by permitting selection of an adequate laser power level range for compensation for fluctuations of the sensitivity characteristic of photosensitive medium and the optical efficiency of exposure system. The photosensitive medium is subject to variations of its sensitivity characteristic due to difference among lots at the time of manufacture and variations of various parameters in long use, and also the optical system is subject to variations of its optical efficiency due to difference of individual machines and contamination. Accordingly, it is sought to permit selection of a laser power level area or region in use by carrying out measurement and check as to whether the optical efficiency of the exposure system of the apparatus is satisfactory or not at present, whether the sensitivity characteristic of the photosensitive medium is quick or slow and whether a desired potential contrast is obtainable. FIG. 20 shows an example of laser power level areas or ranges plotted against the necessary potential contrast. The basic form is the five-level switching as shown in FIG. 17 (P 0 to P 4 ). To these levels, three further levels (P 5 to P 7 ) are added, thus providing five switching power levels P 0 to P 4 multiplied by four areas or regions I to IV. More specifically, in case when the sensitivity characteristic of the photosensitive medium is quick or the optical efficiency of the exposure system is satisfactory, low power levels P 0 to P 4 in region I are used. In the converse case, high power levels P 3 to P 7 in region IV are used. In intermediate characteristic cases, either region II or III is used. FIG. 21 shows a method of selection of region for use through sensitivity characteristic measurement. First, maximum power level P 4 in region I is selected, and a check as to whether a maximum value of necessary potential contrast V 3 -V L (for instance 450 V) is obtainable with certain dark portion potential V D (for instance -700V) is done using P in the aforementioned usual potential control mode. If the maximum value is obtainable, the exposure amount is adequate, and thus the region for use is determined to be region I. Otherwise, the exposure amount is insufficient. In this case, maximum power level P 5 in region II is selected, and similar measurement is performed. In this way, the laser power level region for use is determined. FIG. 22 shows a combination of a determined laser power level region for use and exposure amount switching system shown in FIG. 19. In this example, region II is selected for use, and five power levels P 1 to P 5 are capable of selection. Now, a process from the laser power level switching to the photosensitive medium potential control and then image formation according to the invention will be described. This embodiment also features use of an image forming apparatus, which performs pulse width modulation (PWM) of laser beam according to image data for image formation. Input image data has intermediate tone data of 256 steps from 00 H to FF H (in hexadecimal expression) and permits continuous tone expression from bright area (corresponding to data 00 H ) to dark area (corresponding to FF H ). When this is combined with the invention, high tonality images can be formed more stably. Now, a process up to image formation in the image forming apparatus including the pulse width modulation unit as described above will be described with reference to FIGS. 23 and 24. FIG. 23 is a flow chart illustrating the routine of the process. After start of the potential control operation (step 1), the sensitivity characteristic of the photosensitive medium is performed as shown in FIG. 21 (step 2), and the laser power level area or region for use (regions I to III) is set (step 3). Then the potential contrast (V contrast) necessary for the photosensitive medium is calculated from the measurement of temperature and relative humidity inside and outside the apparatus (step 4). When the necessary potential contrast is calculated, the exposure amount is determined from the relation between power level and necessary potential contrast shown in FIG. 22 (either one of P 1 to P 5 in FIG. 22) (step 5). Using the determined power level, bright area potential corresponding to data 00 H ) and dark area potential (V FF , corresponding to data FF H ) are measured with the grid bias voltage set to three different values (V G-1 to V G-3 ) (step 6). Then, grid bias voltage V for obtaining the necessary potential contrast (V contrast) is calculated from the relation between grid bias voltage and photosensitive medium surface potential as shown in FIG. 16 (step 7). Actual image formation is started using the laser power level calculated in the above process and grid bias voltage V G (step 8). When a certain time is passed or when an environmental variation has taken place, the potential control is started from step 4. Steps 2 and 3 may be executed at necessary intervals for photosensitive medium sensitivity changes or the like will not be brought about in a short period of time. As has been shown, this embodiment permits selection of a laser beam power level area or region for use on the basis of measurement of the sensitivity characteristic of the photosensitive medium and multi-level power switching. Thus, variation of the image quality accompanying the switching of the exposure amount can be minimized to permit constant image quality to be maintained irrespective of any environmental variation. Particularly, with a full-color image forming apparatus in which the gradation is important, it is possible to form high quality image free from color shift at all time. Now, a further embodiment will be described, which permits further compensation of image signal supplied at the time of exposure amount switching. Where image is recorded on photosensitive medium by varying the laser beam intensity through pulse width modulation (PWM) of a laser drive signal according to an input image signal, the relation between the laser beam intensity and pulse width provided as laser drive signal is as shown in FIG. 25. In order to permit use of the linear portion of this characteristic curve as much as possible with levels 00 H (white area) to FF H (black area) (hexadecimal) of image data, minimum level 00 H is set to intensity, at which the curve turns to be linear, and maximum level FF H is set to intensity immediately before the point of deviation of the curve from the linearity. However, when laser power level switching is done, the laser starts light emission from a point of exceeding of a predetermined threshold current. Therefore, the laser beam intensity is varied with the same pulse due to variation of the laser current. Therefore, in the relation between the laser beam intensity and pulse width given to the laser driver at the time of the laser power level switching, different linear regions result as shown by curves 1 and 2 in FIG. 25. Curve 1 results when the laser power level is high, while curve 2 results when the level is low. In order to permit equal image density in correspondence to equal image data irrespective of laser power level changes, the pulse width has to be changed with laser power level switching. This means that it is necessary to provide pulse width modulation circuits corresponding in number to the number of laser power levels for switching. However, even if a modulation circuit for two-level switching between high and low power levels, there are problems of complication of regulating operation and excessive change in exposure amount at the time of switching in case of two-level switching, resulting in extreme image quality changes with changes in the V-E characteristic of the photosensitive medium at the time of switching. The previous second to third embodiments are adapted to provide an increased number of exposure amounts for switching to reduce change in the exposure amount and hence change in the image quality at each switching, thus permitting stable and wide-range control of the potential contrast of the photosensitive medium. In this embodiment, image signal supplied at the time of exposure amount switching is compensated to provide superiority to the previous embodiments in the aspects of cost and regulation characters. The embodiment will now be described in detail. FIG. 27 is a schematic view showing this embodiment of the invention applied to an image forming apparatus using a close contact type color CCD. Copier 80 comprises reader unit 100 and printer unit 200. Original scanning unit 83 is moved in the direction of arrow A for scanning and reading image of original 84 on original table with exposure lamps 85 held "on". Light reflected from the original is led to a converging rod lens array (not shown) to be incident on close contact type color CCD sensor 87. CCD sensor 87 consists of 5 chips arranged in a staggered fashion and each consisting 1,024 pixels each 62.5 microns (1/16 mm) in size. Each pixel is divided into three divisions each of 15.5 microns by 62.5 microns, and C, G and Y filters are applied to the respective divisions. The optical image incident on close contact type color CCD sensor 87 is converted into electric signal for each color. These electric signals are subjected to predetermined processing to be described later in image processing block 88 to obtain color-disassembly image electric signals, which are supplied to printer unit 200 for printing. Color image data from reader unit 100 is subjected to PWM processing to ultimately drive the laser. A laser beam having been modulated in correspondence to image data is scanned at high speed by polygon mirror 89 rotated at high speed and reflected by mirror 90 for dot exposure of the surface of photosensitive drum 91 in correspondence to image. One horizontal line of laser beam scanning corresponds to one horizontal scan line of image and, in this embodiment, has a width of 1/16 mm. Meanwhile, photosensitive drum 91 is rotated at constant speed in the direction of arrow, and thus it is progressively exposed to plan image with the aforementioned laser beam scanning in the main scanning direction and its constant speed rotation in the auxiliary scanning direction. Prior to the exposure, it is uniformly precharged by charger 97, and latent image is formed with the exposure of the pre-charged photosensitive drum. Latent images obtained with given color signals are developed by corresponding color developing units 92 to 95. Considering a first exposure scanning in color reader, for instance, a dot image of yellow component of the original image is formed as latent image on photosensitive drum 91 and developed by yellow developing unit 92. The resultant yellow tonor image is transferred by transfer charger 98 onto paper wound on transfer drum 96 at point of contact of photosensitive drum 91 and transfer drum 96 with each other. Like process is also performed for M (magenta), C (cyan) and Bk (black) colors, and the individual color images are overlapped over one another on paper, thus obtaining a four-color tonor image. FIG. 28 is a block diagram showing a laser driver system inclusive of image processing block 88 in detail. The illustrated structure is the same as the structure shown in FIG. 8 except for gradation control circuit 121'. FIG. 29 is a block diagram showing gradation control circuit 121'. Image data 111 provided as 8-bit data from image processing block 88 of reader unit 100 is supplied to buffer memory 330 in synchronism to synchronizing signal RHSYNC from a sync signal processing unit (not shown) and also with image clock RCLM. Image data stored in buffer memory 330 is read out from the same is synchronism with HSYNC and CLK signal 332 form sync signal control unit 331. In this way, synchronization shift and speed conversion between reader unit 100 and printer unit 200 are effected, and in this state image data is supplied to selector 333. When selection signal 334 from CPU 125-1 of control unit 125 selects input "A" of selector 333, image data is supplied to address of look-up table RAM (LUTRAM) 338. At this time, CPU 125-1 causes reading data from LUTRAM 338 according to control signal 336, and LUTRAM 338 thus provides data corresponding to address input. Data provided from LUTRAM 338 is supplied to selector 339 to be supplied to next selector 340 according to selection signal 334 noted above. When selection signal 342 of selector 340 is selecting input "A", image data from selector 340 is supplied to D/A converter 341 for conversion to analog signal 341-1. Image signal 341-1 having been converted to analog signal is subjected to binary encoding in binary encoding circuit 344. FIG. 30 shows a specific example of binary encoding circuit 344. Triangular wave generator 344-1 generates a triangular wave according to CLK signal 351 having a predetermined frequency provided from sync control unit 331, and the gain and off-set level of the triangular wave are adjusted with respective controls 344-3 and 344-5. Comparator 344-6 compares the adjusted triangular wave to analog image signal 341-1 to form a pulse width modulation (PWM) signal which is supplied to gate circuit 345. The relation between the laser beam intensity and this pulse width is as shown in FIG. 25. In order to permit use of the linear portion of this characteristic curve as mush as possible with levels 00 H to FF H (hexadecimal) of image data, the gain and off-set controls noted above are manually adjusted using optical energy measurement unit in optical path such that minimum power level 00 H of image data corresponds to a point of curve turning to be linear while minimum power level FF H of image data corresponds to a point of curve turning to get out of the linearity. However, when laser power level switching as will be described later is performed, the laser starts to emit laser beam upon exceeding of a predetermined threshold threshold current. Therefore, the laser beam intensity is varied with the same pulse as shown in FIG. 26 because the laser current is varied. Therefore, in the relation between laser beam intensity and pulse width given to laser driver 322 at the time of laser power level switching, different linear regions are formed like curves 1 and 2 as shown in FIG. 25. Curve 1 is formed when the laser power level is high, and curve 2 is formed when the level is low. Accordingly, for obtaining equal image density with the same image data regardless of laser beam intensity changes, it is necessary to vary the pulse width at the time of laser beam intensity switching. At this moment, it will be seen from FIG. 25 that it is mainly in the neighborhood of data 00 H corresponding to the start of laser beam emission that incluence of change in the linear region with respect to the pulse width appears at the time of laser beam intensity switching. The laser beam intensity and linearity of laser beam intensity versus pulse width characteristic in the neighborhood of 00 have great influence on the image quality of the output image. Particularly, where an inverse development system is used, this corresponds to a highlight area in image and can not be ignored as image quality change. In this embodiment, this problem is solved without provision of a plurality of binary encoding circuits as shown in FIG. 31 for respective laser beam intensity levels for switching but by correcting the pulse width of data. This embodiment will now be described with reference to FIG. 31. In this case, the abscissa, unlike the pulse width of laser driving in FIGS. 8 and 9, is taken for video data 00 H to FF H . At the time of actual image formation, only satisfactory linearity regions as shown in FIG. 31 are used. Referring to FIG. 31, with curve 1 for higher laser power, PWM regulation, i.e., setting of pulse width of 00 H and FF H light intensities, is effected using binary encoding circuit 344 shown in FIG. 30. It is seen that in case of lower laser power as represented by curve 2, by reducing the laser drive current to reduce laser power level the laser beam intensity is insufficient and linear region has not been reached yet in the neighborhood of data 00 H of curve 2. It is seen that with curve 2 in FIG. 31 linear region is reached in the neighborhood of data 10 H . Accordingly, in case when the laser power level is reduced in a state with PWM regulation (i.e., setting of pulse width of 00 H and FF H intensities) done with high laser power level, a linear region of 10 H to FF H may be used as video data. That is, in case of low laser power, video data 00 may be corrected to 10. In this embodiment, correction of input data is effected in LUTRAM 338 in gradation control circuit 121' shown in FIG. 29. The contents of the correction are shown in FIG. 32. In FIG. 32, LUT 1 is used in case when providing output image data without correction of input image data with high laser power level. LUT 2 is a table for correcting input image data such as to provide output image data 10 H with respect to input image data 00 H and provide output image data 10 H to FF H with respect to input image data 00 H to FF H . It is used in the case of low laser power as noted before. Thus, irrespective of change in laser power level the same gradation and image density can be obtained by providing corrected data with respect to the same image data. FIG. 33 shows laser driver 322 used in this embodiment in detail. Alteration of constant current supplied to laser 323 can be attained by changing the plus side input voltage to operational amplifier 322-5, and laser power level is switched. The above embodiment has concerned laser beam intensity switching to two levels, but the invention is applicable to cases where the laser beam intensity can be switched to greater numbers of levels as well. FIGS. 34 and 35 illustrate laser beam intensity versus image data characteristic and output image data versus input image data characteristic in case where four laser beam intensities are provided for switching, in conjunction with look-up tables LUT 1 to LUT 4. It will be understood that even when the number of laser beam intensity levels for switching is increased, it is possible to reproduce image with high quality without need of providing the corresponding number of binary encoding circuits but by providing the corresponding number of LUTs for correction. Further, instead of step-by-step switching of the laser beam intensity, it is possible to permit continuous variation of the laser beam intensity. In this embodiment, even when the laser beam intensity is changed, it is possible to provide an optimum pulse width drive signal by correcting an image signal to permit formation of high quality and stable image. The above embodiments of the invention are by no means limitative, and various changes and modifications are possible without departing from the scope of the invention as defined in the claims.
An image forming apparatus has exposure unit for emitting light modified in accordance with image information, the light quantity of said exposure unit being variable, image forming unit for forming image on a photosensitive medium in accordance with light emitted from the exposure unit, detector for detecting the surface state of the photosensitive medium, and controller for optimizing the light quantity of the exposure unit in accordance with the output of the detecting unit. The control unit obtains a potential versus image information variation characteristic of the photosensitive medium based on the output of the detecting unit and sets the light quantity of the exposure unit such that the characteristic approximate a straight line.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "BACKGROUND OF THE INVENTION This invention relates to an image forming apparatus such as a copying machine and a laser beam printer.", "The sensitivity characteristics of a photosensitive member vary with time or variations of environmental conditions such as temperature and humidity.", "To make up for such variations, it has been proposed to measure the sensitivity characteristic of photosensitive medium by the provision of a sensor, control the surface status of a photosensitive drum by varying the corona charger grid voltage or exposure energy at the time of exposure to image through comparison with the measured characteristic and control the output image density to be constant by varying image forming conditions in accordance with detected temperature or humidity by further adding temperature and/or humidity sensor means to the image forming apparatus.", "FIG. 36 shows a prior art example of setting the conditions for image forming through control of the corona charger grid voltage and setting optimum conditions through switching the amount of exposure to laser beam between two levels when a forming condition range exceeds a grid voltage range.", "This method is for controlling the photosensitive drum surface potential contrast as image forming condition.", "In this case, under a constant exposure amount condition, the grid bias is varied continuously, thus varying surface potential V D on the photosensitive medium to vary the grid bias for obtaining desired potential contrast V D -V L .", "However, where the desired potential contrast range is broad, a sufficiently broad variation range can not be obtained with a single exposure amount.", "For this reason, it is proposed to permit switching of the exposure amount between levels for high and low potential contrast ranges as shown in FIG. 37.", "More specifically, when the potential contrast exceeds point B, the exposure amount is switched from level Lo to level Hi.", "In this case of exposure amount switching, the potential contrast control is performed such that the grid bias is varied with the exposure amount to obtain the same potential contrast B and B', as shown in FIG. 36.", "With this method, the potential contrast is controlled from A through B and B'", "to C in a case where it is varied in the increasing direction, while it is controlled from C through B'", "and B to A when it is varied in the reducing direction.", "In this way, it is possible to control the potential contrast over a wide range.", "However, the sensitivity characteristic of photosensitive media varies with individual media.", "In addition, even with photosensitive medium having identical sensitivity charactetistic, there are liable to characteristic variations because of fluctuations of current characteristics of laser in exposure system and optical efficiency of optical system depending on the image forming apparatus.", "With the prior art example noted above, although it is possible to make up for variations with time, it is impossible to make up for initial fluctuations of the sensitivity characteristic of photosensitive medium.", "For example, the relation between surface potential and grid bias voltage shown in FIG. 36 corresponds to either V D1 and V L1 or V D2 and V L2 , as shown in FIG. 39, depending on the sensitivity characteristic of the photosensitive medium.", "If there is desired potential contrast D in this case, with a photosensitive medium having characteristics V D1 and V L1 the desired potential contrast can be obtained by setting grid bias voltage V G2 , but with photosensitive medium with characteristics V D1 and V D2 it can not be obtained with initial preset light amount L 0 (it being assumed that D<B).", "In such prior art example, even if the potential contrast is controlled to be equal at the time of switching of the exposure amount in a potential contrast range subject to the exposure amount switching, i.e., between B and B'", "in FIG. 36, the image quality, particularly the gradation, is subject to variations between points B and B'", "because of the influence of the V-E characteristic (i.e., relation between surface potential and exposure amount) accompanying the switching of the exposure amount.", "More specifically, FIG. 38A shows V-E characteristic of a typical photosensitive medium such as OPC (organic photo-semiconductor).", "As is seen, in this V-E characteristic the potential is not varied linearly with the exposure amount.", "Actual V-E characteristic is as shown in FIG. 38B depending on the maximum exposure amount in use.", "Therefore, in case if photosensitive medium control is carried out by the method noted above such as to obtain potential contrast at point B (B') in FIG. 36, there is a problem that the image quality of the output image is subject to variation when the exposure amount switching is effected with a change in the desired potential contrast due to a slight environmental variation.", "Heretofore, it has been in practice to effect correction of gradation at the time of such exposure amount switching.", "However, it has been difficult to stabilize the image quality with correction corresponding to the exposure amount change.", "Particularly, with a full-color image forming apparatus, in which importance is attached to the gradation, it is necessary to stabilize the gradation.", "SUMMARY OF THE INVENTION The present invention has been intended in the light of the foregoing, and it has an object of providing an improved image forming apparatus.", "Another object of the invention is to provide an image forming apparatus, which permits formation of adequate image at all time irrespective of environmental variations and fluctuations of individual apparatuses.", "A further object of the invention is to provide an image forming apparatus, which permits selection of the sensitivity characteristic of photosensitive medium to be in an optical exposure energy range.", "A still further object of the invention is to provide an image forming apparatus, which permits multi-level exposure energy switching in an exposure energy range selected according to sensitivity characteristic.", "A yet further object of the invention is to provide an image forming apparatus, with which a hysteresis characteristic is provided in a switching characteristic when switching the exposure amount according to the sensitivity characteristic of photosensitive medium.", "A yet another object of the invention is to provide an image forming apparatus, with which an image signal is corrected when switching the exposure amount.", "The above and other objects will become more apparent from the following description when the same is read with reference to the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an image forming apparatus embodying the invention;", "FIG. 2 is a block diagram showing an image processing unit in FIG. 1 in detail;", "FIG. 3 is a waveform chart showing signal waveforms appearing in various parts of the image processing unit shown in FIG. 2;", "FIG. 4 is a graph showing the relation between potential on and exposure amount of a photosensitive medium;", "FIG. 5 is a graph showing the relation between potential and image signal;", "FIGS. 6 and 7 are flow charts illustrating control routines according to the invention;", "FIG. 8 is a schematic representation of a color image forming apparatus as second embodiment of the invention;", "FIG. 9 is a detailed schematic representation of the color image forming apparatus shown in FIG. 8;", "FIG. 10 is a flow chart illustrating a control routine for selecting an exposure energy range according to a contrast potential;", "FIG. 11 is a graph showing an example of exposure energy ranges;", "FIG. 12 is a schematic representation of a color image forming apparatus as third embodiment of the invention;", "FIG. 13 is a graph showing the relation between surface potential on a photosensitive drum and grid bias potential of a corona charger;", "FIG. 14 is a graph showing the relation between exposure amount and necessary potential contrast on a photosensitive drum;", "FIGS. 15 and 16 are graphs showing the relation between exposure amount and necessary potential contrast on a photosensitive drum for illustrating control operation of the embodiment in case when permitting multi-level switching of the exposure amount;", "FIG. 17 is a graph showing the relation between exposure amount and necessary potential contrast;", "FIGS. 18A and 18B are graphs showing the relation between exposure amount and surface potential on photobetween sensitive drum;", "FIG. 19 is a graph showing the relation between exposure amount and necessary contrast potential in case where a hysteresis characteristic is provided for an exposure amount switching characteristic;", "FIGS. 20 and 22 are graphs showing the relation between exposure energy range and necessary potential contrast;", "FIG. 21 is a flow chart illustrating a control operation for selecting an exposure energy range according to a potential contrast;", "FIG. 23 is a flow chart illustrating a potential control routine;", "FIG. 24 is a graph showing the relation between surface potential and grid bias voltage of a charger;", "FIG. 25 is a graph showing the relation between light quantity of laser and pulse width;", "FIG. 26 is a view showing the relation between laser power and light waveform;", "FIG. 27 is a sectional view showing a color copier embodying the invention;", "FIG. 28 is a schematic representation of a laser drive system including a processing block of the same embodiment color copier;", "FIG. 29 is a block diagram showing a gradation control circuit.", "FIG. 30 is a block diagram showing a binary encoding circuit;", "FIGS. 31 and 34 are graphs showing the relation between laser light quantity and video data;", "FIGS. 32 and 35 are graphs showing contents of LUT in the embodiment;", "FIG. 33 is a circuit diagram showing a laser driver;", "and FIGS. 36, 37, 38A, 38B and 39 are graphs for explaining a prior art potential control system.", "DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Now, one embodiment of the invention will be described with reference to the drawings.", "FIG. 1 is a schematic representation of an image forming apparatus (hereinafter referred to as laser printer) as one embodiment of the invention, FIG. 2 is a block diagram showing an image processing unit shown in FIG. 1, FIG. 3 is a waveform chart showing timings of various signals appearing in various parts of the image processing unit shown in FIG. 2, FIG. 4 is a graph showing a potential versus exposure amount characteristic of a photosensitive medium in the same embodiment, FIG. 5 is a graph showing a potential versus image signal characteristic of the same photosensitive medium, FIG. 6 is a flow chart illustrating a control operation of the same embodiment, and FIG. 7 is a flow chart illustrating a separate control operation of the same embodiment.", "In FIG. 1, parts like or corresponding to those in the prior art example are designated by like reference numerals and symbols, while omitting their description again.", "The individual components will first be described.", "Reference numeral 20 designates an image processing unit, which receives digital image data 22 and reference clock signal 23 and provides binary encoded image data obtained as a result of substantially continuous pulse width modulation according to image density (to be described later in detail).", "Binary encoded image data 21 is supplied to laser driving unit 24, which controls the laser beam intensity, thus driving laser 4 to produce a modulated laser beam.", "The laser beam from laser 4, as described before in connection with the prior art example, scans photosensitive medium 1 to form a two-dimensional electrostatic latent image thereon with rotation thereof in the direction of arrow 2.", "The electrostatic latent image is developed by developing unit 5 to be transferred to transfer sheet 7.", "Residual tonor without being transferred is collected by cleaner 10.", "After the transfer, transfer sheet 7 is separated from the photosensitive drum and fed past fixing unit 9 before being discharged.", "Reference numeral 25 designates a potential sensor, which is located in the proximity of the surface of photosensitive medium 1 at a position after a position of exposure of medium 1 to laser beam and detects the potential of electrostatic latent image on the photosensitive medium surface.", "The output of potential sensor 25 is supplied to potential measurement unit 26 for measurement of potential.", "The output of potential sensor 25 is an analog signal and is converted by A/D converter 27 into a digital signal which is supplied to control unit 28.", "Control unit 28 includes a microcomputer (hereinafter referred to as CPU), a ROM which stores control programs and data of the CPU, a RAM as word area of the CPU, as well as various I/O ports and A/D converters.", "It controls the entire laser printer and also provides command signals as analog signals to various controlled units to be described later.", "Reference numeral 29 designates a high voltage control unit for controlling charging current of charger 3, and 30 a high voltage control unit for controlling a grid bias voltage applied to charger 3.", "Reference numeral 31 designates a developing bias control unit for controlling a developing bias voltage applied to developing unit 5.", "The operation of the image processing unit shown in FIG. 1 will now be described with reference to FIGS. 2 and 3.", "FIG. 2 is a block diagram showing the detailed construction of image processing unit 20 shown in FIG. 1, and FIG. 3 shows timings of signals appearing in various parts shown in FIG. 2. Referring to the block diagram of FIG. 2, digital image data 22 is converted by D/A converter 202 into analog image signal 203 to be supplied to one input terminal of comparator 211.", "Timing signal generator 207 produces pixel clock 204 and screen clock 208 according to reference clock signal 23 supplied to timing signal generator 207 and provides screen clock 208 to pattern signal generator 209 and pixel clock 204 to D/A converter 202.", "Pattern signal generator 209 produces pattern signal 210 on the basis of screen clock 208, signal 210 being supplied to the other input terminal of comparator 211.", "Referring to the timing chart of FIG. 3, digital image data 22 is supplied in synchronism to pixel clock 204, and D/A converter 202 supplies analog image signal 203 to one input terminal of comparator 211 in synchronism to pixel clock 204.", "Screen clock 208 is a clock signal having an integral multiple of the cycle period of pixel clock 204 and defines the cycle period of pattern signal 210, which is, for instance, a triangular wave as shown.", "Analog image signal 203 and pattern signal 210 supplied to comparator 211 are compared in comparator 211.", "As a result, binary encoded image data 21 is produced, which is "0"", "of analog image signal 203 is greater and "1"", "otherwise.", "In the case of timings shown in FIG. 3, screen clock 208 has double the cycle period of pixel clock 204.", "In this case, binary encoded image data 21 has a pulse waveform obtained as a result of pulse modulation according to pattern signal 210 as digital image signal 22 is changes stepwise from 00 (white) to hexadecimal FF (black).", "Variation of the amplitude of pattern signal 210, which is a triangular wave for instance, permits variation of the relation between the input level of digital image data 22 and pulse width of binary encoded image data 21.", "Binary encoded image data 21 obtained as a result of pulse width modulation in the above way, is supplied to laser driving unit 24 and converted in unit 24 into a current waveform having a pulse width corresponding to the input data for driving semiconductor laser 4.", "It will be seen from the above description that the average exposure amount of the photosensitive medium is increased with increasing image signal toward FF (black) and hence increasing semiconductor laser "on"", "time per pixel.", "Further, current I on when semiconductor laser 4 shown in FIG. 1 is "on", can be varied according to a command signal from control unit 28.", "In other words, the laser beam intensity is increased by increasing current I on and is reduced by reducing I on .", "That is, the average exposure amount of the photosensitive medium is increased with increasing I on , and this means that a desired exposure amount can be obtained through control of the laser beam intensity.", "Now, the sensitivity of photosensitive medium and output image density characteristic will be described with reference to FIGS. 4 and 5.", "The relation between the potential or charge on and sensitivity or exposure amount of photosensitive medium 1 (FIG.", "1) (i.e., V-E characteristic) varies with individual photosensitive media, and even with identical photosensitive media it varies depending on conditions and time of its use.", "Further, semiconductor laser drive current and apparent photosensitive medium sensitivity such as image data and photosensitive medium potential vary with variation of current-intensity characteristic of semiconductor laser 4 and transmittivity of focusing optical system.", "FIG. 4 shows the V-E characteristic of photosensitive medium.", "The ordinate is taken for the potential, and the abscissa for the exposure amount.", "Labeled Vd is a potential in the case of absence of exposure.", "This potential is equal to the initial charging potential by charger 3.", "With increasing exposure amount the charge is reduced, and hence the absolute value of potential is reduced.", "This relation is represented by curve Y. While curve Y is linear over a low exposure amount range, it shows saturation in a high exposure amount range.", "In FIG. 4, the average exposure amount of and potential of the photosensitive medium are respectively P FF and V FF when the digital image signal is FF (black) and are respectively P 00 and V 00 when the image signal is 00 (white).", "With exposure amount P FF at point A (FIG.", "4), potential changes between V 00 and V FF for a corresponding image signal range between 00 (white) and FF (black) are as shown by curve a in FIG. 5. With exposure amount P FF at point B (FIG.", "4), the potential versus image signal characteristic is represented by curve b in FIG. 5. As is seen from curves a and b, even if the output density at V 00 and V FF are constant irrespective of P FF , the density varies for intermediate image signals, and curve b has a higher γ value (i.e., tanθ or difference in the vertical direction divided by difference in the horizontal direction) and leads to cruch in a high density range.", "Further, even with the same exposure amount of P FF , sensitivity variation of individual photosensitive media leads to characteristic variation like that shown in FIG. 5. In this embodiment, the laser drive current is determined such that linearity is approached by variation of the photosensitive medium potential corresponding to exposure amount variation due to variation of the image signal.", "Now, light amount control will be described on the basis of the photosensitive medium sensitivity and output image density characteristic described above with reference to the flow charts of FIGS. 6 and 7.", "FIGS. 6 and 7 show flow charts of light amount control routine programs stored in ROM of control unit 28 (FIG.", "1).", "Referring to FIG. 6, when the light amount control is started in step 6a, step 6b is executed, in which photosensitive medium is pre-rotated in the direction of arrow 2 for erasing residual potential.", "In subsequent step 6c, initial charging current of charger and initial laser drive current are set.", "In subsequent steps 6d to 6f, potential sensor 25 measures average potentials V FF , V 80 and V 00 of photosensitive medium corresponding to predetermined exposures FF (black), 80 (gray) and 00 (white) among pulse width modulation laser exposures according to binary encoded image data (FIG.", "2) obtained in image processing unit 20 from the respective preset laser bean intensities noted above.", "In subsequent step 6g, shape coefficient K is calculated from measured values of V FF , V 80 and V 00 obtained in steps 6d to 6f.", "##EQU1## The value of K represents the ratio of the potential drop for an intermediate image density and maximum potential drop between OO (white) and FF (black).", "With a usual photosensor, K approaches 0.5 if the potential-exposure characteristic is linear while it approaches unity if the characteristic is non-linear (FIG.", "5).", "Desired value K 0 of the shape coefficient is set to 0.6 to 0.7.", "In this case, the lower limit is set in order to reduce shape coefficient K so as to obtain linearity while preventing the exposure amount from being set to be excessively small by excessively demanding the linearity.", "In subsequent steps 6n and 6i, the value of shape coefficient obtained in step 6g is compared to desired value K 0 , for instance 0.6 to 0.7.", "If the value of K calculated from the measurement is greater than the desired value range, the routine goes to step 6j to reduce the laser drive current to a predetermined extent so as to reduce the laser beam intensity and then goes back to step 6d.", "If coefficient K is less than the desired value range, the routine goes to step 6k to increase the laser drive current to a predetermined extent and then goes back to step 6d.", "If it is determined that coefficient K is in the desired value range (i.e., 0.6 to 0.7 in the instant case), it is determined that adequate linearity is obtained, and the routine goes to step 6l to bring an end to the exposure control operation.", "In the above case, the drive current is changed every time the measurement of V FF , V 80 and V 00 is effected.", "However, it is possible to obtain the same results through pulse width control.", "FIG. 7 shows a control flow chart in case of the pulse width control.", "Referring to FIG. 7, steps 7a to 7c are like respective steps 6a to 6c in FIG. 6. In steps 7d 1 to 7d 16 (i.e., a total of 16 steps), the pulse width for turn-on of laser 4 is changed in each step to effect exposure of photosensitive medium 1, and potential is measured in each step and stored in RAM of control unit 28.", "For example, in step 7d 1 the pulse width for turn-on of laser 4 is set to 0, and potential V 0 of zero exposure is measure and stored in RAM.", "Subsequently, the pulse width is increased to a predetermined extent, and in step 7d 2 potential V 16 is measured again.", "Then, the average exposure amount on the photosensor is set such that it is increased linearly according to the pulse width (FIG.", "5).", "In this way, up to potential V 16 in step 7d 16 is measured and stored in RAM.", "In subsequent step 7e, the following calculation is performed with respect to potential data V 0 to V 16 stored in RAM.", "##EQU2## where n=2, 3, .", ", 26 The value of n is obtained, with which the value of K n is a desired value, for instance 0.6 to 0.7, and preliminarily obtained laser drive current I n is set, with which exposure amount P with n-th pulse width in steps 7d 1 to 7d 16 is equal to maximum exposure amount P FF at the time of actual exposure to image (step 7f).", "The control operation is ended in step 7g.", "It is further possible to obtain voltage measurement without pulse width control but by changing the sole laser drive current.", "As has been shown, with this embodiment it is possible to obtain image output having stable gradation irrespective of photosensitive medium sensitivity changes by determining the potential-exposure characteristic and obtaining an exposure condition such as to approximate a linear characteristic.", "Now, a different embodiment of the invention will be described, which permits selection of an exposure energy range suited for the characteristic of photosensitive medium and selection of optimum liquid quantity in the selected range.", "FIG. 8 is a schematic representation of a color copier as this embodiment.", "Image data 111 provided from a leader unit (not shown) is supplied to gradation control circuit 121 of printer unit 200.", "Gradation control circuit 121 has a function of synchronizing image clocks of the reader unit and printer unit 200, these clocks having different rates, and also a function of providing for correspondence between image data and color reproduction density of printer unit 200.", "Output data from gradation control circuit 121 is supplied to laser driver 122 to drive semiconductor laser 123 for image formation.", "Control unit 125 of printer unit 200, which communicates with the reader unit via communication control line 124, includes control elements of unit 200.", "Reference numeral 126 designates a potential sensor for detecting charge on photosensitive medium 129, and 127 a potential measurement unit for converting the output from potential sensor 126 into a digital signal which is supplied to control unit 125.", "Potential data supplied to control unit 125 is read out by CPU 125-1 in control unit 125 to be used for control.", "A signal from sensor 128 for detecting an image end signal (ITOP) is supplied to control unit 125 for controlling the printing operation.", "Temperature and humidity sensors 199 and 198 are supplied through A/D converter 125-4 to control unit 125 for compensation for development characteristics.", "Relative humidity AH is the ratio of steam to saturated steam air at each temperature and is given as ΔH=f(T, H) where T represents the temperature, and H the relative humidity sensor value.", "The function f is usually expressed as a cubic equation.", "T and H are provided as outputs of temperature and relative humidity sensors 199 and 198, and these two outputs are A/D converted in A/D converter 125-4 of the control unit for calculation with resultant digital data to obtain the relative humidity.", "Control for determining the charger grid bias voltage is performed according to the relative humidity thus obtained.", "In ROM 125-3 operation programs are stored, and RAM 125-4 is used as working area in the operation of CPU 125-1.", "FIG. 9 shows the construction of FIG. 8 in greater detail.", "Reference numeral 129 designates an electrophotographic photosensitive drum rotated in the direction of arrow.", "Photosensitive medium 129 is first uniformly pre-charged by charger 130, and then it is exposed by being scanned with laser beam 131, which is obtained by on-off modulation according to a modulating signal, in a direction perpendicular to the direction of its rotation.", "As a result, an electrostatic latent image is formed on photosensitive medium 129, and it is then developed by developing unit 132 to obtain a visible image.", "Although not shown, this embodiment includes four developing units for respective colors Y, M, C and B K .", "The visible tonor image formed on photosensitive medium 129 is transferred by transfer charger 133 onto transfer medium 134 held on transfer drum 150, and then it is fixed by a fixing unit (not shown).", "Meanwhile, residual tonor remaining on photosensitive medium 129 after transfer is removed by cleaning unit 135.", "Subsequently, residual charge remaining on photosensitive medium 129 is removed by removal light from lamp 136.", "The above sequence of operations is repeated.", "Digital video signal that is supplied is latched by latch 201 and then supplied to D/A converter 202 for conversion to analog video signal AV which is supplied to one input terminal of comparator 204.", "To the other input terminal of comparator 204 is supplied triangular wave signal CIS provided from triangular wave generator 205.", "Comparator 204 compares analog video signal AV and triangular wave signal CIS and provides pulse width modulation signal E, which is supplied to laser driver 122.", "According to signal E, semiconductor laser 123 is driven to provide laser beam 31, which is produced through on-off modulation according to modulation signal E. Laser beam 131 provided from semiconductor laser 137 is scanned by scanner 138, which may be polygon mirror, galvano-mirror, etc.", "Reference numeral 139 designates a lens for focusing laser beam 131 as spot on photosensitive medium 129, and 140 a mirror for bending the optical path.", "Reference numeral 203 designates dynamic range regulation means for regulating the dynamic range of the analog video signal provided in a predetermined check mode from the D/A converter according to signal from CPU 125-1.", "Reference numeral 208 designates bias regulation means for regulating the triangular wave bias provided in a predetermined check mode from triangular wave generator 205 according to signal from CPU 125-1.", "Reference numeral 206 designates a selector for selecting signal supplied to D/A converter 202.", "More specifically, it selects either digital video signal latched in latch 201 or signal from pattern generator 207 according to signal from CPU 125-1.", "Pattern generator 207 generates data 00 and FF to be used in a laser power processing routine to be described later.", "A laser power selection process will now be described.", "FIG. 10 is a flow chart illustrating the control routine for the processing.", "In the processing, an input "A"", "selection signal is supplied to selector 206 to drive pattern generator 207 so as to provide a predetermined pattern for reading the surface potential on photosensitive medium 129, and optimum laser power is selected according to the read-out value.", "The program of this routine is stored in ROM 125-3.", "Now, the processing will be described with reference to the flow chart.", "In step S2, "A"", "input to selector 206 is selected to supply data from pattern generator 207 to D/A converter 202.", "In step S3, surface potential V 00 on photosensitive medium 129 due to the provided laser beam is read out through potential measurement unit 127 according to data, for instance 00 H , from pattern generator 207.", "In step S4, surface potential V FF corresponding to hexadecimal data FF H is similarly read out.", "In steps S3 and S4, equal primary high voltage is provided.", "In step S5, a check is done as to whether the difference between V 00 and V FF is a predetermined value.", "If the difference is the predetermined value, preset laser power level P is selected in step S7.", "If the former is greater than the latter, power level P 1 lower than P 0 is selected in step S8.", "If the former is less than the latter, power level P 2 higher than P 1 is selected in step S9.", "Laser power levels P 0 , P 1 , .", ", P n (n being an integer given as n≧0), and the selected power level can be obtained by varying the drive current of the laser driver.", "A predetermined value of V 00 -V FF is provided such that a desired potential contrast can be obtained by using level P 1 .", "With the characteristic of photosensitive medium selected in the laser power level selection processing as shown above and with laser power level P 1 selected to P 1 , the laser power level is changed such as P 1 -P 2 →P 3 as the necessary potential contrast is varied with environmental variation.", "With laser power level P 2 selected in the processing the power level is changed such as P 2 →P 3 →P 4 .", "to attain stabilization of the image density and gradation.", "FIG. 11 shows an example of power level switching according to the necessary potential contrast.", "In this instance, n is 7.", "If either one of power levels P 0 to P 3 is selected in the laser power level selection processing noted above, it means that it means that either one of ranges or areas I to IV is selected depending on the sensitivity characteristic of the pertaining photosensitive medium or optical efficiency of the exposure system or like factors.", "If the relation between P n and P n-1 is set such that the V-E characteristic (i.e., charging potential versus exposing energy characteristic) of the photosensitive medium is constant, it is possible to eliminate variation of the gradation due to power level switching.", "The above processing can be carried out when the photosensitive medium or exposure system is replaced or at a certain interval.", "As is shown, in this embodiment either one of preliminarily provided ranges or areas I to IV is selected in the laser power level selection processing (i.e., steps S5 to S9) depending on whether the value of V 00 -V FF V FF is the same or greater or less than a predetermined value.", "As an alternative to the above processing, it is possible to have the values of V 00 -V FF and primary high voltage predetermined and permit continuous laser power level such as to regulate V 00 -V FF to a predetermined value using APC (automatic power control), for instance.", "In this case, once initial P is set, the power level is varied according to the necessary potential contrast while drawing the same curve as the power level curves shown in FIG. 11.", "As has been shown above, by selecting an adequate exposure energy range for making up for fluctuations of the sensitivity characteristic of the photosensitive medium and optical efficiency of the exposure system it is possible to obtain the necessary potential contrast at all time for attaining image stabilization.", "Now, a further embodiment will be described, in which a switching characteristic when switching the exposure amount according to the necessary potential contrast is provided with a hysteresis characteristic.", "FIG. 12 is a schematic representation of a full-color image forming apparatus as embodiment of the invention.", "Laser control unit 201 produces a laser beam modulated according to an image input signal.", "Polygon mirror 202 having a plurality of rotary mirror surfaces is rotated at a constant speed by a scanner motor (not shown) for deflecting the incident laser beam.", "Reference numeral 203 is a focusing lens, which is an optical lens having a f/θ characteristic, and 204 a photosensitive drum as photosensitive medium, which is exposed to incident laser beam to form electrostatic latent image.", "Photosensitive drum 204 is rotated in the direction of arrow.", "Reference numeral 205 designates a discharging lamp for discharging the surface of photosensitive drum 204 to provide uniform potential thereon, 206 a corona charger for uniformly charging the surface of photosensitive drum 204, and 207 a grid electrode serving as control electrode when uniformly charging the surface of photosensitive drum 204.", "Developing means 208a to 206d develope electrostatic latent image formed on photosensitive drum 4 with respective developers (i.e., magenta, cyan, yellow and black developers) according to developing biases applied to respective developing sleeves Sa to Sd.", "Reference numeral 209 designates a transfer drum carrying a transfer sheet fed from transfer sheet cassette 210, 211 a transfer charger for transferring tonor image formed on photosensitive drum 204 onto the transfer sheet carried by transfer drum 209, 212 a separating pawl for separating transfer sheet after transfer of the individual color tonor images from transfer drum 209, 213 a fixing unit for fixing the tonor image transferred onto the transfer sheet, 214 a discharging tray, on which transfer sheets with fixed tonor images are stacked, 215 a cleaning unit for recovering residual tonor remaining on photosensitive drum 204, 216 a potential sensor provided in the proximity of photosensitive drum 4 at a position after the position of exposure to laser beam and serving to detect the latent image potential, 217 an A/D converter for converting analog output of potential sensor 216 into a digital output, and 218 voltage control unit consisting of a microcomputer including a RAM as data and control data memory means and a CPU as bias calculation means and control means.", "D/A converter 219 converts control data determined by voltage control unit 218 into analog data and provides control data to high voltage control unit 220a, which controls voltage applied to charger 206, and also to grid bias voltage control unit 220b, which controls grid bias voltage applied to grid electrode 7, and developing bias data to developing bias voltage control circuits 221a to 221d for controlling developing units 208a to 208d.", "Now, the operation of controlling the surface potential on photosensitive drum 204 will be described with reference to FIGS. 13 and 14.", "In this embodiment, as in the prior art example, the setting of conditions for image formation is effected through control of the voltage applied to grid electrode 207 of corona charger 206 according to data obtained from potential sensor 216.", "Further, when a grid voltage control range is exceeded by image formation condition range, i.e., necessary potential contrast V D -V L , the amount of exposure of photosensitive drum 204 to laser beam is switched to change potential V on bright portion of the drum surface (V L (Hi) ←→V L (Lo)), thus permitting a broader potential contrast range to be obtained.", "(FIG.", "13).", "However, when the exposure amount is switched, the image quality, particularly gradation, is varied due to influence of the V-E characteristic of photosensitive drum 204.", "Therefore, it is desired to dispense with the exposure amount switching as much as possible.", "To solve this problem, in this embodiment, as shown in FIG. 14, the exposure amount switching is effected at different potential contrast in case when switching Lo over to Hi and in case when switching Hi over to Lo.", "More specifically, in this embodiment the switching of the exposure amount from the side of Lo over to the side of Hi is effected when necessary potential contrast V D -V L becomes predetermined value V C (C C'), but the switching from the side of Hi over to the side of Lo is not effected upon reaching of value V but is effected only when lower value V B is reached (B'", "B).", "In other words, a hysteresis characteristic is provided to the characteristic of switching of the exposure amount according to necessary potential contrast V D -V L .", "When obtaining the necessary potential contrast of V C through such control, after switching of the exposure amount from Lo over to Hi the exposure amount is not switched upon reaching of V C by the potential contrast again but is switched when and only when the potential contrast is reduced to V B which is lower than V C .", "Therefore, even when the potential contrast is varied slightly due to environmental variation, the exposure amount is not switched, thus permitting constant image quality to be maintained.", "In the above embodiment the exposure amount is switched between two levels, but this is by no means limitative, and the invention is applicable to an apparatus permits switching of more than two levels as well.", "FIG. 15 is a graph showing exposure amount variation in an apparatus, in which the exposure amount is subject to switching among six levels according to necessary potential contrast V D -V L .", "By permitting such frequent exposure amount switching, the exposure amount change at the time of switching is reduced to alleviate variation of the regulation property accompanying the V-E characteristic of photosensitive drum 204.", "On the demerit side, however, the points of switching are increased, and the exposure amount is switched frequently even with slight environmental variations, thus resulting in degradation of the image quality.", "However, by controlling the exposure amount in the above method such that a hysteresis characteristic is provided at each point of switching as shown in FIG. 16, once the exposure amount is switched, constant exposure amount can be maintained unless a great environmental variation takes place.", "Therefore, by applying the invention to such apparatus, with which the gradation is subject to less change when switching the exposure amount, it is possible to obtain very high image quality.", "The above switching of the exposure amount between two levels and among six levels is by no means limitative, and the invention is applicable to an apparatus, in which the exposure amount is switched among any number of different levels.", "Now, a further embodiment will be described, in which an adequate one of a plurality of exposure energy ranges is selected according to the necessary potential contrast, and the exposure amount is switched among a plurality of levels in the selected exposure energy range with a hysteresis characteristic provided to the switching characteristic.", "The construction of apparatus of this embodiment is the same as shown in FIG. 12.", "FIG. 17 is a graph showing exposure amount variation of an apparatus, in which the exposure amount is switched among five levels according to necessary potential contrast V D -V L .", "With such frequent switching of the exposure amount, the exposure amount change at the time of switching is reduced to alleviate variation of the gradation accompanying changes in the V-E characteristic of photosensitive drum 204 as noted above.", "The variation of the gradation can be alleviated by reducing the exposure amount change to 20% or below.", "FIGS. 18A and 18B show V-E characteristic changes in case where the exposure amount is switched among five levels with a change of about 20%.", "Doing so permits considerable alleviation of the variation of the gradation at the time of switching, as is seen from FIG. 18B.", "The variation of the gradation at the time of switching can be substantially ignored if the change in the exposure amount is set to 10% or below.", "While this embodiment has concerned switching of the exposure amount among five levels, this is by no means limitative, and sufficient effects are obtainable so long as the exposure amount can be switched among at least three levels.", "As shown above, with control of the exposure amount switching such as to provide a hysteresis at each point of switching the frequency of switching can be greatly reduced, and variation of the gradation at the time of switching can be extremely reduced by increasing the number of switching levels and setting the change at each switching to be 20% or below.", "From the above, if the exposure amount switching is controlled with a hysteresis provided at each point of switching, once the exposure amount is switched a constant exposure can be maintained unless great environmental variation takes place.", "By applying the invention to such apparatus, in which the gradation is subject to less variation at the time of switching of the exposure amount, therefore, it is possible to obtain very high image quality.", "Further, this embodiment seeks to attain stabilization of image by permitting selection of an adequate laser power level range for compensation for fluctuations of the sensitivity characteristic of photosensitive medium and the optical efficiency of exposure system.", "The photosensitive medium is subject to variations of its sensitivity characteristic due to difference among lots at the time of manufacture and variations of various parameters in long use, and also the optical system is subject to variations of its optical efficiency due to difference of individual machines and contamination.", "Accordingly, it is sought to permit selection of a laser power level area or region in use by carrying out measurement and check as to whether the optical efficiency of the exposure system of the apparatus is satisfactory or not at present, whether the sensitivity characteristic of the photosensitive medium is quick or slow and whether a desired potential contrast is obtainable.", "FIG. 20 shows an example of laser power level areas or ranges plotted against the necessary potential contrast.", "The basic form is the five-level switching as shown in FIG. 17 (P 0 to P 4 ).", "To these levels, three further levels (P 5 to P 7 ) are added, thus providing five switching power levels P 0 to P 4 multiplied by four areas or regions I to IV.", "More specifically, in case when the sensitivity characteristic of the photosensitive medium is quick or the optical efficiency of the exposure system is satisfactory, low power levels P 0 to P 4 in region I are used.", "In the converse case, high power levels P 3 to P 7 in region IV are used.", "In intermediate characteristic cases, either region II or III is used.", "FIG. 21 shows a method of selection of region for use through sensitivity characteristic measurement.", "First, maximum power level P 4 in region I is selected, and a check as to whether a maximum value of necessary potential contrast V 3 -V L (for instance 450 V) is obtainable with certain dark portion potential V D (for instance -700V) is done using P in the aforementioned usual potential control mode.", "If the maximum value is obtainable, the exposure amount is adequate, and thus the region for use is determined to be region I. Otherwise, the exposure amount is insufficient.", "In this case, maximum power level P 5 in region II is selected, and similar measurement is performed.", "In this way, the laser power level region for use is determined.", "FIG. 22 shows a combination of a determined laser power level region for use and exposure amount switching system shown in FIG. 19.", "In this example, region II is selected for use, and five power levels P 1 to P 5 are capable of selection.", "Now, a process from the laser power level switching to the photosensitive medium potential control and then image formation according to the invention will be described.", "This embodiment also features use of an image forming apparatus, which performs pulse width modulation (PWM) of laser beam according to image data for image formation.", "Input image data has intermediate tone data of 256 steps from 00 H to FF H (in hexadecimal expression) and permits continuous tone expression from bright area (corresponding to data 00 H ) to dark area (corresponding to FF H ).", "When this is combined with the invention, high tonality images can be formed more stably.", "Now, a process up to image formation in the image forming apparatus including the pulse width modulation unit as described above will be described with reference to FIGS. 23 and 24.", "FIG. 23 is a flow chart illustrating the routine of the process.", "After start of the potential control operation (step 1), the sensitivity characteristic of the photosensitive medium is performed as shown in FIG. 21 (step 2), and the laser power level area or region for use (regions I to III) is set (step 3).", "Then the potential contrast (V contrast) necessary for the photosensitive medium is calculated from the measurement of temperature and relative humidity inside and outside the apparatus (step 4).", "When the necessary potential contrast is calculated, the exposure amount is determined from the relation between power level and necessary potential contrast shown in FIG. 22 (either one of P 1 to P 5 in FIG. 22) (step 5).", "Using the determined power level, bright area potential corresponding to data 00 H ) and dark area potential (V FF , corresponding to data FF H ) are measured with the grid bias voltage set to three different values (V G-1 to V G-3 ) (step 6).", "Then, grid bias voltage V for obtaining the necessary potential contrast (V contrast) is calculated from the relation between grid bias voltage and photosensitive medium surface potential as shown in FIG. 16 (step 7).", "Actual image formation is started using the laser power level calculated in the above process and grid bias voltage V G (step 8).", "When a certain time is passed or when an environmental variation has taken place, the potential control is started from step 4.", "Steps 2 and 3 may be executed at necessary intervals for photosensitive medium sensitivity changes or the like will not be brought about in a short period of time.", "As has been shown, this embodiment permits selection of a laser beam power level area or region for use on the basis of measurement of the sensitivity characteristic of the photosensitive medium and multi-level power switching.", "Thus, variation of the image quality accompanying the switching of the exposure amount can be minimized to permit constant image quality to be maintained irrespective of any environmental variation.", "Particularly, with a full-color image forming apparatus in which the gradation is important, it is possible to form high quality image free from color shift at all time.", "Now, a further embodiment will be described, which permits further compensation of image signal supplied at the time of exposure amount switching.", "Where image is recorded on photosensitive medium by varying the laser beam intensity through pulse width modulation (PWM) of a laser drive signal according to an input image signal, the relation between the laser beam intensity and pulse width provided as laser drive signal is as shown in FIG. 25.", "In order to permit use of the linear portion of this characteristic curve as much as possible with levels 00 H (white area) to FF H (black area) (hexadecimal) of image data, minimum level 00 H is set to intensity, at which the curve turns to be linear, and maximum level FF H is set to intensity immediately before the point of deviation of the curve from the linearity.", "However, when laser power level switching is done, the laser starts light emission from a point of exceeding of a predetermined threshold current.", "Therefore, the laser beam intensity is varied with the same pulse due to variation of the laser current.", "Therefore, in the relation between the laser beam intensity and pulse width given to the laser driver at the time of the laser power level switching, different linear regions result as shown by curves 1 and 2 in FIG. 25.", "Curve 1 results when the laser power level is high, while curve 2 results when the level is low.", "In order to permit equal image density in correspondence to equal image data irrespective of laser power level changes, the pulse width has to be changed with laser power level switching.", "This means that it is necessary to provide pulse width modulation circuits corresponding in number to the number of laser power levels for switching.", "However, even if a modulation circuit for two-level switching between high and low power levels, there are problems of complication of regulating operation and excessive change in exposure amount at the time of switching in case of two-level switching, resulting in extreme image quality changes with changes in the V-E characteristic of the photosensitive medium at the time of switching.", "The previous second to third embodiments are adapted to provide an increased number of exposure amounts for switching to reduce change in the exposure amount and hence change in the image quality at each switching, thus permitting stable and wide-range control of the potential contrast of the photosensitive medium.", "In this embodiment, image signal supplied at the time of exposure amount switching is compensated to provide superiority to the previous embodiments in the aspects of cost and regulation characters.", "The embodiment will now be described in detail.", "FIG. 27 is a schematic view showing this embodiment of the invention applied to an image forming apparatus using a close contact type color CCD.", "Copier 80 comprises reader unit 100 and printer unit 200.", "Original scanning unit 83 is moved in the direction of arrow A for scanning and reading image of original 84 on original table with exposure lamps 85 held "on".", "Light reflected from the original is led to a converging rod lens array (not shown) to be incident on close contact type color CCD sensor 87.", "CCD sensor 87 consists of 5 chips arranged in a staggered fashion and each consisting 1,024 pixels each 62.5 microns (1/16 mm) in size.", "Each pixel is divided into three divisions each of 15.5 microns by 62.5 microns, and C, G and Y filters are applied to the respective divisions.", "The optical image incident on close contact type color CCD sensor 87 is converted into electric signal for each color.", "These electric signals are subjected to predetermined processing to be described later in image processing block 88 to obtain color-disassembly image electric signals, which are supplied to printer unit 200 for printing.", "Color image data from reader unit 100 is subjected to PWM processing to ultimately drive the laser.", "A laser beam having been modulated in correspondence to image data is scanned at high speed by polygon mirror 89 rotated at high speed and reflected by mirror 90 for dot exposure of the surface of photosensitive drum 91 in correspondence to image.", "One horizontal line of laser beam scanning corresponds to one horizontal scan line of image and, in this embodiment, has a width of 1/16 mm.", "Meanwhile, photosensitive drum 91 is rotated at constant speed in the direction of arrow, and thus it is progressively exposed to plan image with the aforementioned laser beam scanning in the main scanning direction and its constant speed rotation in the auxiliary scanning direction.", "Prior to the exposure, it is uniformly precharged by charger 97, and latent image is formed with the exposure of the pre-charged photosensitive drum.", "Latent images obtained with given color signals are developed by corresponding color developing units 92 to 95.", "Considering a first exposure scanning in color reader, for instance, a dot image of yellow component of the original image is formed as latent image on photosensitive drum 91 and developed by yellow developing unit 92.", "The resultant yellow tonor image is transferred by transfer charger 98 onto paper wound on transfer drum 96 at point of contact of photosensitive drum 91 and transfer drum 96 with each other.", "Like process is also performed for M (magenta), C (cyan) and Bk (black) colors, and the individual color images are overlapped over one another on paper, thus obtaining a four-color tonor image.", "FIG. 28 is a block diagram showing a laser driver system inclusive of image processing block 88 in detail.", "The illustrated structure is the same as the structure shown in FIG. 8 except for gradation control circuit 121'.", "FIG. 29 is a block diagram showing gradation control circuit 121'.", "Image data 111 provided as 8-bit data from image processing block 88 of reader unit 100 is supplied to buffer memory 330 in synchronism to synchronizing signal RHSYNC from a sync signal processing unit (not shown) and also with image clock RCLM.", "Image data stored in buffer memory 330 is read out from the same is synchronism with HSYNC and CLK signal 332 form sync signal control unit 331.", "In this way, synchronization shift and speed conversion between reader unit 100 and printer unit 200 are effected, and in this state image data is supplied to selector 333.", "When selection signal 334 from CPU 125-1 of control unit 125 selects input "A"", "of selector 333, image data is supplied to address of look-up table RAM (LUTRAM) 338.", "At this time, CPU 125-1 causes reading data from LUTRAM 338 according to control signal 336, and LUTRAM 338 thus provides data corresponding to address input.", "Data provided from LUTRAM 338 is supplied to selector 339 to be supplied to next selector 340 according to selection signal 334 noted above.", "When selection signal 342 of selector 340 is selecting input "A", image data from selector 340 is supplied to D/A converter 341 for conversion to analog signal 341-1.", "Image signal 341-1 having been converted to analog signal is subjected to binary encoding in binary encoding circuit 344.", "FIG. 30 shows a specific example of binary encoding circuit 344.", "Triangular wave generator 344-1 generates a triangular wave according to CLK signal 351 having a predetermined frequency provided from sync control unit 331, and the gain and off-set level of the triangular wave are adjusted with respective controls 344-3 and 344-5.", "Comparator 344-6 compares the adjusted triangular wave to analog image signal 341-1 to form a pulse width modulation (PWM) signal which is supplied to gate circuit 345.", "The relation between the laser beam intensity and this pulse width is as shown in FIG. 25.", "In order to permit use of the linear portion of this characteristic curve as mush as possible with levels 00 H to FF H (hexadecimal) of image data, the gain and off-set controls noted above are manually adjusted using optical energy measurement unit in optical path such that minimum power level 00 H of image data corresponds to a point of curve turning to be linear while minimum power level FF H of image data corresponds to a point of curve turning to get out of the linearity.", "However, when laser power level switching as will be described later is performed, the laser starts to emit laser beam upon exceeding of a predetermined threshold threshold current.", "Therefore, the laser beam intensity is varied with the same pulse as shown in FIG. 26 because the laser current is varied.", "Therefore, in the relation between laser beam intensity and pulse width given to laser driver 322 at the time of laser power level switching, different linear regions are formed like curves 1 and 2 as shown in FIG. 25.", "Curve 1 is formed when the laser power level is high, and curve 2 is formed when the level is low.", "Accordingly, for obtaining equal image density with the same image data regardless of laser beam intensity changes, it is necessary to vary the pulse width at the time of laser beam intensity switching.", "At this moment, it will be seen from FIG. 25 that it is mainly in the neighborhood of data 00 H corresponding to the start of laser beam emission that incluence of change in the linear region with respect to the pulse width appears at the time of laser beam intensity switching.", "The laser beam intensity and linearity of laser beam intensity versus pulse width characteristic in the neighborhood of 00 have great influence on the image quality of the output image.", "Particularly, where an inverse development system is used, this corresponds to a highlight area in image and can not be ignored as image quality change.", "In this embodiment, this problem is solved without provision of a plurality of binary encoding circuits as shown in FIG. 31 for respective laser beam intensity levels for switching but by correcting the pulse width of data.", "This embodiment will now be described with reference to FIG. 31.", "In this case, the abscissa, unlike the pulse width of laser driving in FIGS. 8 and 9, is taken for video data 00 H to FF H .", "At the time of actual image formation, only satisfactory linearity regions as shown in FIG. 31 are used.", "Referring to FIG. 31, with curve 1 for higher laser power, PWM regulation, i.e., setting of pulse width of 00 H and FF H light intensities, is effected using binary encoding circuit 344 shown in FIG. 30.", "It is seen that in case of lower laser power as represented by curve 2, by reducing the laser drive current to reduce laser power level the laser beam intensity is insufficient and linear region has not been reached yet in the neighborhood of data 00 H of curve 2.", "It is seen that with curve 2 in FIG. 31 linear region is reached in the neighborhood of data 10 H .", "Accordingly, in case when the laser power level is reduced in a state with PWM regulation (i.e., setting of pulse width of 00 H and FF H intensities) done with high laser power level, a linear region of 10 H to FF H may be used as video data.", "That is, in case of low laser power, video data 00 may be corrected to 10.", "In this embodiment, correction of input data is effected in LUTRAM 338 in gradation control circuit 121'", "shown in FIG. 29.", "The contents of the correction are shown in FIG. 32.", "In FIG. 32, LUT 1 is used in case when providing output image data without correction of input image data with high laser power level.", "LUT 2 is a table for correcting input image data such as to provide output image data 10 H with respect to input image data 00 H and provide output image data 10 H to FF H with respect to input image data 00 H to FF H .", "It is used in the case of low laser power as noted before.", "Thus, irrespective of change in laser power level the same gradation and image density can be obtained by providing corrected data with respect to the same image data.", "FIG. 33 shows laser driver 322 used in this embodiment in detail.", "Alteration of constant current supplied to laser 323 can be attained by changing the plus side input voltage to operational amplifier 322-5, and laser power level is switched.", "The above embodiment has concerned laser beam intensity switching to two levels, but the invention is applicable to cases where the laser beam intensity can be switched to greater numbers of levels as well.", "FIGS. 34 and 35 illustrate laser beam intensity versus image data characteristic and output image data versus input image data characteristic in case where four laser beam intensities are provided for switching, in conjunction with look-up tables LUT 1 to LUT 4.", "It will be understood that even when the number of laser beam intensity levels for switching is increased, it is possible to reproduce image with high quality without need of providing the corresponding number of binary encoding circuits but by providing the corresponding number of LUTs for correction.", "Further, instead of step-by-step switching of the laser beam intensity, it is possible to permit continuous variation of the laser beam intensity.", "In this embodiment, even when the laser beam intensity is changed, it is possible to provide an optimum pulse width drive signal by correcting an image signal to permit formation of high quality and stable image.", "The above embodiments of the invention are by no means limitative, and various changes and modifications are possible without departing from the scope of the invention as defined in the claims." ]
RELATED APPLICATIONS [0001] This application claims priority to Eurasian Patent Application No. EA201101158, filed Sep. 1, 2011, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0002] The present method refers to digital image processing namely, to systems processing images obtained with the use of TV camera and intended for image noise reduction. BACKGROUND OF THE INVENTION [0003] Quality of images obtained with the use of TV camera can deteriorate due to noise. This noise is required to be reduced what will result in image quality improving. [0004] The method of noise reduction in an image obtained with the use of TV camera is known from the patent US2009154825, published on 18 Jun. 2009, comprising a generation of an output frame out of the frame video flow, having timing interdependency; averaging closely adjacent values of frame elements in one group of frames; and the use of average values considering weight coefficients to form an output frame. [0005] The method of noise reduction in an image is known from the patent EP 0289152, comprising a generation of an image out of the frame video flow. Each video frame is formed from the frame video flow by the following way. A comparison of each frame under processing including appropriate elements of previous frames is performed. The comparison results in defining relations used, considering weight coefficients, to form averaged elements of output frames. SUMMARY OF THE INVENTION [0006] The present invention resulted in noise reduction in an image obtained with the use of TV camera. [0007] The technical result in the method of noise reduction in an image obtained with the use of TV camera comprising in a video channel a generation of a video flow consisting of groups of frames, having timing interdependency; generation video image from a sequence of output frames obtained by processing the said frame groups by averaging closely adjacent values of appropriate pixels at least in one group of pixels; and the use of averaged values considering weight coefficients to form an output frame is achieved by processing groups of frames comprising odd number, that is 2N+1, where N≧1 frames being time—symmetrically juxtaposed against frame under processing with the numbers from -N to N inclusive, where 0 is the number of the frame under processing, in which the noise is being reduced, 1 is the number of the following frame, -N is the number of the oldest frame and N is the number of the newest frame; by defining values of frame pixels time -symmetrically juxtaposed against the frame under processing, and their average values; by calculating the modulus of the said difference with the pixel value of the frame under processing, as a pixel value of the frame under processing are selected considering weight coefficients such pixel values that correspond to the minimal modulus of the difference. [0008] The method of noise reduction in an image obtained with the use of TV camera comprising a generation of a frame video flow out of frame groups, having timing interdependency; a generation of an image out of output frame series obtained by means of processing of the said frame groups by the use of averaging closely adjacent pixel values in at least one group of frames; and the use of average values considering weight coefficients to form an output frame. [0009] For noise reduction the frames are used that time—symmetrically juxtaposed against the frame under processing forth and back in time. It is understood that for calculation of averaged value of any pixel either appropriate pixel values of one frame or other one, or an averaged pixel value of both these frames is used. To select one out of three values the modulus of the differences of these values with the meaning of frame under processing are calculated, then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging. While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing. The amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction. [0010] The method provides noise reduction in an image obtained with the use of TV camera. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 shows a processing block diagram; and [0012] FIG. 2 shows a block diagram of the group processing module. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] Since noise in a channel can cause errors in a modulus of the difference calculation and therefore, incorrect operation of the noise reducer so the differences are calculated over three in one row adjacent pixels for a noisy video channel. For that purpose a modulus of the difference for the frame under processing and two adjacent pixels are calculated then, a value for further processing by means of a median filter is selected. [0014] The claimed method is realized in software as media data provided with a guide to execute the said method. [0015] FIG. 1 shows a processing block diagram for N=3, where: [0016] 1 is a group processing module, 2 is a multiplier, 3 is an adder, 4 is a divisor. [0017] Frame pixels −3÷3 are divided into three groups each of which incorporates a frame under processing and two time-symmetrically juxtaposed against it. Video—flows from every group are transferred to the module 1 (group processing modules). To every module are also transferred weight coefficients K 1 -K 3 correspondingly. Besides, pixels of the frame under processing and coefficient KO are transferred to the multiplier 2 . From the outputs of the module 1 pixel and coefficients values which are used to calculate the said pixel values are transferred to the adders 3 . Pixel values are transferred to one adder and, those of coefficients to another one. From the outputs of adders 3 total pixel value and total coefficient value are transferred to the divisor 4 . Resulting value of noise reduction is read from the output of the divisor 4 . [0018] FIG. 2 shows a block diagram of the group processing module 1 where: 5 —arithmetical average computer, 6 —modulus of the difference computer, 7 —half a modulus of the difference computer, 8 —modulus of the difference minimal selection unit. [0019] Four values are transferred to the group processing module: pixel values of the frame under processing, pixel values time-symmetrically juxtaposed against a frame and coefficient by which pixel values of this group are multiplied. Pixel values of symmetrical frames are transferred to the arithmetical average computer 5 . Obtained average value and pixel value of the frame under processing are transferred to the half a modulus of the difference computer 7 . To modulus of the difference computer 6 are transferred pixel values of symmetrical frames. Three obtained modulus of the differences are transferred to the modulus of the difference minimal selection unit 8 . Depending on what modulus of the difference turns out minimal to the 8 unit output is transferred either pixel value of one of the symmetrical frames or average value of both these frames. In addition, if an average value is selected in the unit 8 , the coefficient K is multiplied by 2. [0020] In specific embodiment versions of the claimed method: [0021] weight coefficient values can be selected in correlation with frame pair remoteness from the frame under processing; [0022] weight coefficient values can be calculated considering one parameter equal to a width of a bell-shaped curve as a function of coefficient via frame number, that width defines the extent of noise reduction; [0023] amount of frames employed for processing as a parameter of noise reduction; [0024] amount of frames employed for processing is selected to be double width of a bell-shaped curve; [0025] modulus of the difference is calculated for a processed pixel and two adjacent pixels in a row and as a resulted value is selected one of three values employing a median filter. [0026] A distinctive characteristic of the claimed method is that for noise reduction time-symmetrically juxtaposed against the frame under processing forth and back in time frames are used. It is understood that for calculation of averaged value of any pixel either appropriate pixel values of one frame or other one, or an averaged pixel value of both these frames is used. To select one out of three values the modulus of the differences of these values with the meaning of the frame under processing are calculated, then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging. While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing. Amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction. [0027] To select one out of three values the modulus of the differences of these values with the meaning of the frame under processing are calculated then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging. While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing. Amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction. [0028] The following precedence rule is executed in the method. [0029] A sequence comprising N frames is obtained, where N is the frame number. Then the odd number of frames are processed simultaneously, that is N+1 frames being time—symmetrically juxtaposed against the frame under processing with the numbers from -N to N inclusive, where 0 is the number of the current frame, in which the noise is being reduced, −1 is the number of the previous frame, 1 is the number of the next frame—N is the number of the oldest frame and N is the number of the newest frame. [0030] For each pixel of the frame under processing a new value is calculated in the following way. [0031] With the aim of clarification let us introduce the following notations: [0032] P-N(x,y) is a pixel value of the oldest frame, [0033] P-N+1(x,y) is a pixel value of the next frame, [0034] P 0 (x,y) is a pixel value of the frame under processing, [0035] PN(x,y) is a pixel value of the newest frame. [0036] Here: [0037] y is an image row number, [0038] x is a pixel position in the image row. [0039] The following algorithm is used to calculate an output frame. [0040] Coefficients for frame pair KM are calculated where M is a number of a frame pair time—symmetrically juxtaposed against the frame under processing, correspondingly M varies from 1 to N, the sum of productions of a pixel value and coefficient ΣPK equate with 0, the sum of coefficients ΣK equate with 0, the P 0 (x,y) value of the pixel under processing is multiplied by the coefficient K 0 and added to ΣPK, K 0 is added to ΣK for all frame pairs time—symmetrically juxtaposed against the frame under processing that is for all M values from 1 to N, the following operations are implemented: [0041] a modulus of the differences of pixel values firstly, with the frame numbers 0 and -M then 0 and M; 0 and an average pixel value for frame numbers -M and M are calculated. [0000] D−M=|P 0( x,y )− P−M ( x,y )| [0000] DM=|P 0( x,y )− PM ( x,y )| [0000] DA=|P 0( x,y )−( P−M ( x,y )+ PM ( x,y ))/21/2 [0042] the minimal values of D-M, DM, DA are determined [0043] if a minimal value turned out to be D-M, ΣPK is added to P-M(x,y) * KM, and to ΣK is added KM. If a minimal value turned out to be DM, so to ΣPK is added PM(x,y) * KM, and to ΣK is also added KM. If a minimal value turned out to be DA, so to ΣPK is added (P-M(x,y)+PM(x,y)) * KM, and to ΣK is added 2* KM. [0044] After processing of all M frame pairs the resulted pixel value can be computed in the following way [0000] P out (x,y)=Σ PK/ΣK. [0045] A required extent of noise reduction determines KM coefficient selection. [0046] There are two special coefficient sets. The first set corresponds to maximal extent of noise reduction with all coefficients being equal to 1. The second set corresponds to the complete absence of noise reduction with all coefficients equal to 0, except of KO that is equal to 1. For noise reduction intermediate values the coefficients are calculated so that the coefficients for the frames juxtaposed to the current frame (frame “0”) be close to K 0 in their value and decrease at moving off. Other variants can be developed in different ways. [0047] One of the method embodiment versions is that the coefficient value via frame number dependence is given by a bell-shaped curve; the width of the bell-shaped curve will determine the noise reduction extent. The example of such a function: [0000] For i<R [0000] Ki =(cos( i·π/R )+1.0) [0000] For i>R [0000] Ki=0. [0048] Here R is a parameter determining noise reduction extent. At R>>N all coefficients are equal and noise reduction extent is minimal. At R<1 all values except the average are equal to “0”, a noise reducer will be practically OFF. R=2 means that the average frame will be ON with the coefficient of 0.5, and two adjacent ones—with 0.25, that is the width of the bell will be 2. [0049] The method assumes that there is a delay N in image output. Therefore, when selecting a cell number a compromise between desired maximal noise reduction extent and minimal delay in image output shall be taken into consideration. [0050] In the claimed method such artifacts as brightness jump tailing are decreased significantly due to their average frame—symmetrically juxtaposition that is the artifact is divided by two sides and its visibility diminishes sharply. In addition, at gradual brightness variation due to filtering of frames having average frame—symmetrically juxtaposition noise reduction extent increases significantly even at image change. Besides, if the image stops changing either against an average one or does not change up to the current frame the noise reduction extent keeps remaining high. Moreover, in the claimed version settling time is limited by a selected cell number. [0051] The claimed method can be realized with the use of known hardware. An example of method embodiment is shown in FIGS. 1 and 2 .
A method of noise reduction in an image obtained with the use of TV camera comprising a generation of a frame video flow out of frame groups, having timing interdependency; a generation of an image out of output frame series obtained by means of processing of the said frame groups by the use of averaging closely adjacent pixel values in at least one group of frames; and the use of average values considering weight coefficients to form an output frame.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "RELATED APPLICATIONS [0001] This application claims priority to Eurasian Patent Application No. EA201101158, filed Sep. 1, 2011, which is incorporated herein by reference in its entirety.", "FIELD OF THE INVENTION [0002] The present method refers to digital image processing namely, to systems processing images obtained with the use of TV camera and intended for image noise reduction.", "BACKGROUND OF THE INVENTION [0003] Quality of images obtained with the use of TV camera can deteriorate due to noise.", "This noise is required to be reduced what will result in image quality improving.", "[0004] The method of noise reduction in an image obtained with the use of TV camera is known from the patent US2009154825, published on 18 Jun. 2009, comprising a generation of an output frame out of the frame video flow, having timing interdependency;", "averaging closely adjacent values of frame elements in one group of frames;", "and the use of average values considering weight coefficients to form an output frame.", "[0005] The method of noise reduction in an image is known from the patent EP 0289152, comprising a generation of an image out of the frame video flow.", "Each video frame is formed from the frame video flow by the following way.", "A comparison of each frame under processing including appropriate elements of previous frames is performed.", "The comparison results in defining relations used, considering weight coefficients, to form averaged elements of output frames.", "SUMMARY OF THE INVENTION [0006] The present invention resulted in noise reduction in an image obtained with the use of TV camera.", "[0007] The technical result in the method of noise reduction in an image obtained with the use of TV camera comprising in a video channel a generation of a video flow consisting of groups of frames, having timing interdependency;", "generation video image from a sequence of output frames obtained by processing the said frame groups by averaging closely adjacent values of appropriate pixels at least in one group of pixels;", "and the use of averaged values considering weight coefficients to form an output frame is achieved by processing groups of frames comprising odd number, that is 2N+1, where N≧1 frames being time—symmetrically juxtaposed against frame under processing with the numbers from -N to N inclusive, where 0 is the number of the frame under processing, in which the noise is being reduced, 1 is the number of the following frame, -N is the number of the oldest frame and N is the number of the newest frame;", "by defining values of frame pixels time -symmetrically juxtaposed against the frame under processing, and their average values;", "by calculating the modulus of the said difference with the pixel value of the frame under processing, as a pixel value of the frame under processing are selected considering weight coefficients such pixel values that correspond to the minimal modulus of the difference.", "[0008] The method of noise reduction in an image obtained with the use of TV camera comprising a generation of a frame video flow out of frame groups, having timing interdependency;", "a generation of an image out of output frame series obtained by means of processing of the said frame groups by the use of averaging closely adjacent pixel values in at least one group of frames;", "and the use of average values considering weight coefficients to form an output frame.", "[0009] For noise reduction the frames are used that time—symmetrically juxtaposed against the frame under processing forth and back in time.", "It is understood that for calculation of averaged value of any pixel either appropriate pixel values of one frame or other one, or an averaged pixel value of both these frames is used.", "To select one out of three values the modulus of the differences of these values with the meaning of frame under processing are calculated, then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging.", "While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing.", "The amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction.", "[0010] The method provides noise reduction in an image obtained with the use of TV camera.", "BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 shows a processing block diagram;", "and [0012] FIG. 2 shows a block diagram of the group processing module.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] Since noise in a channel can cause errors in a modulus of the difference calculation and therefore, incorrect operation of the noise reducer so the differences are calculated over three in one row adjacent pixels for a noisy video channel.", "For that purpose a modulus of the difference for the frame under processing and two adjacent pixels are calculated then, a value for further processing by means of a median filter is selected.", "[0014] The claimed method is realized in software as media data provided with a guide to execute the said method.", "[0015] FIG. 1 shows a processing block diagram for N=3, where: [0016] 1 is a group processing module, 2 is a multiplier, 3 is an adder, 4 is a divisor.", "[0017] Frame pixels −3÷3 are divided into three groups each of which incorporates a frame under processing and two time-symmetrically juxtaposed against it.", "Video—flows from every group are transferred to the module 1 (group processing modules).", "To every module are also transferred weight coefficients K 1 -K 3 correspondingly.", "Besides, pixels of the frame under processing and coefficient KO are transferred to the multiplier 2 .", "From the outputs of the module 1 pixel and coefficients values which are used to calculate the said pixel values are transferred to the adders 3 .", "Pixel values are transferred to one adder and, those of coefficients to another one.", "From the outputs of adders 3 total pixel value and total coefficient value are transferred to the divisor 4 .", "Resulting value of noise reduction is read from the output of the divisor 4 .", "[0018] FIG. 2 shows a block diagram of the group processing module 1 where: 5 —arithmetical average computer, 6 —modulus of the difference computer, 7 —half a modulus of the difference computer, 8 —modulus of the difference minimal selection unit.", "[0019] Four values are transferred to the group processing module: pixel values of the frame under processing, pixel values time-symmetrically juxtaposed against a frame and coefficient by which pixel values of this group are multiplied.", "Pixel values of symmetrical frames are transferred to the arithmetical average computer 5 .", "Obtained average value and pixel value of the frame under processing are transferred to the half a modulus of the difference computer 7 .", "To modulus of the difference computer 6 are transferred pixel values of symmetrical frames.", "Three obtained modulus of the differences are transferred to the modulus of the difference minimal selection unit 8 .", "Depending on what modulus of the difference turns out minimal to the 8 unit output is transferred either pixel value of one of the symmetrical frames or average value of both these frames.", "In addition, if an average value is selected in the unit 8 , the coefficient K is multiplied by 2.", "[0020] In specific embodiment versions of the claimed method: [0021] weight coefficient values can be selected in correlation with frame pair remoteness from the frame under processing;", "[0022] weight coefficient values can be calculated considering one parameter equal to a width of a bell-shaped curve as a function of coefficient via frame number, that width defines the extent of noise reduction;", "[0023] amount of frames employed for processing as a parameter of noise reduction;", "[0024] amount of frames employed for processing is selected to be double width of a bell-shaped curve;", "[0025] modulus of the difference is calculated for a processed pixel and two adjacent pixels in a row and as a resulted value is selected one of three values employing a median filter.", "[0026] A distinctive characteristic of the claimed method is that for noise reduction time-symmetrically juxtaposed against the frame under processing forth and back in time frames are used.", "It is understood that for calculation of averaged value of any pixel either appropriate pixel values of one frame or other one, or an averaged pixel value of both these frames is used.", "To select one out of three values the modulus of the differences of these values with the meaning of the frame under processing are calculated, then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging.", "While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing.", "Amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction.", "[0027] To select one out of three values the modulus of the differences of these values with the meaning of the frame under processing are calculated then the minimal modulus of the difference is defined and appropriate pixel value is used for averaging.", "While averaging selected pixel values are multiplied by coefficients that depend on remoteness extent from the frame under processing.", "Amount of frames employed in the method and functional coefficient dependence on remoteness extent from the frame under processing define parameters for noise reduction.", "[0028] The following precedence rule is executed in the method.", "[0029] A sequence comprising N frames is obtained, where N is the frame number.", "Then the odd number of frames are processed simultaneously, that is N+1 frames being time—symmetrically juxtaposed against the frame under processing with the numbers from -N to N inclusive, where 0 is the number of the current frame, in which the noise is being reduced, −1 is the number of the previous frame, 1 is the number of the next frame—N is the number of the oldest frame and N is the number of the newest frame.", "[0030] For each pixel of the frame under processing a new value is calculated in the following way.", "[0031] With the aim of clarification let us introduce the following notations: [0032] P-N(x,y) is a pixel value of the oldest frame, [0033] P-N+1(x,y) is a pixel value of the next frame, [0034] P 0 (x,y) is a pixel value of the frame under processing, [0035] PN(x,y) is a pixel value of the newest frame.", "[0036] Here: [0037] y is an image row number, [0038] x is a pixel position in the image row.", "[0039] The following algorithm is used to calculate an output frame.", "[0040] Coefficients for frame pair KM are calculated where M is a number of a frame pair time—symmetrically juxtaposed against the frame under processing, correspondingly M varies from 1 to N, the sum of productions of a pixel value and coefficient ΣPK equate with 0, the sum of coefficients ΣK equate with 0, the P 0 (x,y) value of the pixel under processing is multiplied by the coefficient K 0 and added to ΣPK, K 0 is added to ΣK for all frame pairs time—symmetrically juxtaposed against the frame under processing that is for all M values from 1 to N, the following operations are implemented: [0041] a modulus of the differences of pixel values firstly, with the frame numbers 0 and -M then 0 and M;", "0 and an average pixel value for frame numbers -M and M are calculated.", "[0000] D−M=|P 0( x,y )− P−M ( x,y )| [0000] DM=|P 0( x,y )− PM ( x,y )| [0000] DA=|P 0( x,y )−( P−M ( x,y )+ PM ( x,y ))/21/2 [0042] the minimal values of D-M, DM, DA are determined [0043] if a minimal value turned out to be D-M, ΣPK is added to P-M(x,y) * KM, and to ΣK is added KM.", "If a minimal value turned out to be DM, so to ΣPK is added PM(x,y) * KM, and to ΣK is also added KM.", "If a minimal value turned out to be DA, so to ΣPK is added (P-M(x,y)+PM(x,y)) * KM, and to ΣK is added 2* KM.", "[0044] After processing of all M frame pairs the resulted pixel value can be computed in the following way [0000] P out (x,y)=Σ PK/ΣK.", "[0045] A required extent of noise reduction determines KM coefficient selection.", "[0046] There are two special coefficient sets.", "The first set corresponds to maximal extent of noise reduction with all coefficients being equal to 1.", "The second set corresponds to the complete absence of noise reduction with all coefficients equal to 0, except of KO that is equal to 1.", "For noise reduction intermediate values the coefficients are calculated so that the coefficients for the frames juxtaposed to the current frame (frame “0”) be close to K 0 in their value and decrease at moving off.", "Other variants can be developed in different ways.", "[0047] One of the method embodiment versions is that the coefficient value via frame number dependence is given by a bell-shaped curve;", "the width of the bell-shaped curve will determine the noise reduction extent.", "The example of such a function: [0000] For i<R [0000] Ki =(cos( i·π/R )+1.0) [0000] For i>R [0000] Ki=0.", "[0048] Here R is a parameter determining noise reduction extent.", "At R>>N all coefficients are equal and noise reduction extent is minimal.", "At R<1 all values except the average are equal to “0”, a noise reducer will be practically OFF.", "R=2 means that the average frame will be ON with the coefficient of 0.5, and two adjacent ones—with 0.25, that is the width of the bell will be 2.", "[0049] The method assumes that there is a delay N in image output.", "Therefore, when selecting a cell number a compromise between desired maximal noise reduction extent and minimal delay in image output shall be taken into consideration.", "[0050] In the claimed method such artifacts as brightness jump tailing are decreased significantly due to their average frame—symmetrically juxtaposition that is the artifact is divided by two sides and its visibility diminishes sharply.", "In addition, at gradual brightness variation due to filtering of frames having average frame—symmetrically juxtaposition noise reduction extent increases significantly even at image change.", "Besides, if the image stops changing either against an average one or does not change up to the current frame the noise reduction extent keeps remaining high.", "Moreover, in the claimed version settling time is limited by a selected cell number.", "[0051] The claimed method can be realized with the use of known hardware.", "An example of method embodiment is shown in FIGS. 1 and 2 ." ]
BACKGROUND OF THE INVENTION [0001] The present invention relates to a semiconductor laser device and a fabrication method therefor, and, more particularly, to a semiconductor laser device which can be used preferably as a light source for an optical disk apparatus or the like and a fabrication method therefor. [0002] In a semiconductor laser device, particularly in an AlGaInP semiconductor laser device in which the heterojunction between an active layer and a clad layer cannot have a sufficiently high barrier, a technology for controlling impurity doping has an important influence on the characteristics of the device. [0003] Specifically, there has been conventionally known an AlGaInP semiconductor laser device wherein the clad layer adjacent to the active layer is left undoped by controlling the position at which impurity doping is performed during the fabrication thereof. The conventional AlGaInP semiconductor laser having such a structure is advantageous in that the diffusion of the impurity from the clad layer into the active layer can be prevented. [0004] However, the conventional AlGaInP semiconductor laser device described above has the problem that, when the position at which impurity is performed is further away from the active layer, the efficiency of conversion from an injected current to light deteriorates so that the operating current thereof increases. Conversely, when the position at which impurity doping is performed is closer to the active layer, the problem occurs that the diffusion of the impurity reaches the interior of the active layer due to a thermal process or the like and the deterioration of the device occurs within a short time of about several hours to reduce the lifetime of the device and consequently degrade the reliability of the device. [0005] Thus, in the conventional AlGaInP semiconductor laser, it has been necessary to control impurity doping with high accuracy so that considerable difficulty has been encountered in the fabrication thereof. [0006] To reduce the difficulty, Japanese Laid-Open Patent Publication No. HEI 11-87831 proposes a semiconductor laser device having a structure which can not only prevent the diffusion of an impurity into the active layer but also improve light emission efficiency, reduce the operating current, and suppress the reliability degradation of the device by controlling the lattice mismatch of the clad layer with respect to a semiconductor substrate. [0007] However, the semiconductor laser device having the structure which controls the lattice mismatch of the clad layer with respect to the semiconductor substrate described above has had the problem that a crystal defect occurs in the active layer and the long term reliability of the device cannot be guaranteed, though the impurity diffusion into the active layer can be prevented. In addition, the semiconductor laser device also has had the problem that the setting of process conditions in forming a ridge waveguide is difficult and the production yield thereof is low. SUMMARY OF THE INVENTION [0008] In view of the foregoing, it is therefore an object of the present invention to provide a semiconductor laser device having a structure which allows an improvement in the reliability of the device and a fabrication method therefor. Another object of the present invention is to provide a laser device having a structure which allows easy formation of a ridge waveguide and a fabrication method for a laser device in which a ridge waveguide can be easily formed. [0009] As a result of conducting intensive studies, the present inventors have found that, when a clad layer has a unidirectional distortion, which is either a compressive distortion or a tensile distortion, with respect to a semiconductor substrate, a crystal defect occurs in an active layer and degrades the reliability of a device. The present invention has been achieved in view of the foregoing findings and provides a semiconductor laser device comprising a clad layer having both of the compressive distortion and the tensile distortion. [0010] Specifically, a semiconductor laser device according to a first aspect of the present invention is a semiconductor laser device having a multilayer structure comprising a first clad layer, an active layer, and a second clad layer stacked successively on a semiconductor substrate in order of increasing distance from the semiconductor substrate, wherein at least one of the first clad layer and the second clad layer has a compressive distortion with respect to the semiconductor substrate and at least one of the first clad layer and the second clad layer includes a semiconductor layer having a tensile distortion with respect to the semiconductor substrate. [0011] In the semiconductor laser device according to the first aspect of the present invention, at least one of the first and second clad layers has the compressive distortion with respect to the semiconductor substrate so that the lattice spacing of a crystal is reduced. As a result, it is possible to effectively prevent the diffusion of an impurity into the active layer. In addition, at least one of the first and second clad layers having the compressive distortion includes therein the semiconductor layer having the tensile distortion with respect to the semiconductor substrate so that the compressive distortion and the tensile distortion each with respect to the semiconductor substrate cancel out each other. This suppresses the occurrence of a crystal defect in the active layer and improves the reliability of the semiconductor laser device. [0012] The compressive distortion with respect to the semiconductor substrate indicates herein that the magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is positive. The tensile distortion with respect to the semiconductor substrate indicates herein that the magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is negative. The magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is given by Δa/a=(a 2 −a 1 )/a 1 wherein a 1 represents the lattice constant of the semiconductor substrate and a 2 represents the lattice constant of the semiconductor layer. [0013] Preferably, in the semiconductor laser device according to the first aspect of the present invention, at least one of the first clad layer and the second clad layer having the compressive distortion has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate and the semiconductor layer having the tensile distortion has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate. According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented. [0014] Preferably, in the semiconductor laser device according to the first aspect of the present invention, the second clad layer has the semiconductor layer having the tensile distortion and the semiconductor layer having the tensile distortion functions as an etching stop layer when a ridge portion is formed in the second clad layer by etching. [0015] According to the preferred embodiment, it becomes possible to easily form the ridge portion in the second clad layer by using the semiconductor layer functioning as the etching stop layer. As a result, the production yield of the device of which the long term reliability is guaranteed is improved. [0016] A semiconductor laser device according to a second aspect of the present invention is a semiconductor laser device having a multilayer structure comprising a first clad layer, an active layer, and a second clad layer stacked successively on a semiconductor substrate in order of increasing distance from the semiconductor substrate, wherein at least one of the first clad layer and the second clad layer has a compressive distortion with respect to the semiconductor substrate and at least one of the first clad layer and the second clad layer has a heavily doped impurity region containing an impurity at a relatively high concentration and a lightly doped impurity region containing an impurity at a relatively low concentration. [0017] In the semiconductor laser device according to the second aspect of the present invention, at least one of the first and second clad layers has the compressive distortion with respect to the semiconductor substrate so that the lattice spacing of a crystal is reduced. As a result, it is possible to effectively prevent the diffusion of an impurity into the active layer. In addition, at least one of the first and second clad layers has an impurity concentration difference therein so that the occurrence of a crystal defect in the active layer is suppressed and the reliability of the semiconductor laser device is improved. [0018] Preferably, in the semiconductor laser device according to the second aspect of the present invention, the heavily doped impurity region is formed at a position further away from the active layer than a position at which the lightly doped impurity region is formed and the lightly doped impurity region is formed at a position closer to the active layer than at the position at which the heavily doped impurity region is formed. According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented. [0019] Preferably, in the semiconductor laser device according to the second aspect of the present invention, at least one of the first clad layer and the second clad layer includes a semiconductor layer having a tensile distortion with respect to the semiconductor substrate. According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented. [0020] Preferably, in the semiconductor laser device according to the second aspect of the present invention, at least one of the first clad layer and the second clad layer having the compressive distortion has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate. According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented. [0021] Preferably, in the semiconductor laser device according to the second aspect of the present invention, the semiconductor layer having the tensile distortion has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate. According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented. [0022] Preferably, in the semiconductor laser device according to the second aspect of the present invention, a well layer composing the active layer has the compressive distortion with respect to the semiconductor substrate and a film thickness of not less than 20 nm. The preferred embodiment is effective in improving the reliability of the device. [0023] Even when the semiconductor laser device according to the second aspect of the present invention has a self-sustained pulsation characteristic which increases the operating current in high temperature condition, the reliability of the device is improved. [0024] A method for fabricating a semiconductor laser device according to an aspect of the present invention comprises the steps of: forming, on a semiconductor substrate, a first clad layer having a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate; forming an active layer on the first clad layer; forming, on the active layer, a second clad layer having a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate and including therein a semiconductor layer having a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate; and etching the second clad layer using the semiconductor layer as an etching stop layer to form a ridge portion therein. [0025] In accordance with the method for fabricating a semiconductor laser device according to the aspect of the present invention, it is possible to suppress the occurrence of a crystal defect in the active layer, easily fabricate the device of which the long term reliability is guaranteed, and improve the production yield thereof by using the etching stop layer. [0026] According to the present invention, a semiconductor laser device having a structure with excellent reliability and a fabrication therefor can be provided. BRIEF DESCRIPTION OF THE DRAWINGS [0027] FIG. 1 is a cross-sectional view showing a structure of a semiconductor laser device according to a first embodiment of the present invention; [0028] FIGS. 2A to 2C are cross-sectional views illustrating a method for fabricating the semiconductor laser device according to the first embodiment in the order in which the process steps thereof are performed; [0029] FIG. 3 is a graph showing the relationship between an aging time and a current degradation rate when an aging test is performed on the semiconductor laser device according to the first embodiment; [0030] FIG. 4 is a graph showing the relationship between the lattice mismatch of clad layers and reliability in the semiconductor laser device according to the first embodiment; [0031] FIG. 5 is a list of the results of an experiment performed under combined conditions for the reliability evaluation of semiconductor laser devices having different structures in the first embodiment; and [0032] FIG. 6 is a cross-sectional view showing a structure of a semiconductor laser device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0033] Referring now to the drawings, the individual embodiments of the present invention will be described herein below. Embodiment 1 [0034] FIG. 1 is a cross-sectional view of a semiconductor laser device according to the first embodiment of the present invention. [0035] As shown in FIG. 1 , a buffer layer 102 made of n-type GaAs having a thickness of 500 nm, a lower clad layer 103 made of n-type AlGaInP having a thickness of 1200 nm, an active layer 104 having a quantum well structure made of GaInP, a first upper clad layer 105 a made of p-type AlGaInP having a thickness of 400 nm, an etching stop layer 106 made of p-type GaInP having a thickness of 6 nm, a second upper clad layer 105 b made of p-type AlGaInP having a thickness of 600 nm, an intermediate layer 107 made of p-type GaInP having a thickness of 50 nm, and a contact layer 108 made of p-type GaAs having a thickness of 200 nm are formed successively in an ascending order on a substrate 101 made of n-type GaAs. The second upper clad layer 105 b , the intermediate layer 107 , and the contact layer 108 constitute a striped ridge waveguide. A current block layer 109 made of n-type GaAs having a thickness of 400 nm is further formed over the side surfaces of the striped ridge waveguide and the upper surface of the etching stop layer 106 . A p-type electrode 110 is formed over the contact layer 108 and the current block layer 109 , while an n-type electrode 111 is formed on the back surface of the substrate 101 . [0036] A description will be given herein below to a specific method for fabricating the semiconductor layer according to the first embodiment thus constructed. [0037] FIGS. 2A to 2C are cross-sectional views for illustrating the process steps of the method for fabricating the semiconductor laser device according to the first embodiment. [0038] First, as shown in FIG. 2A , the buffer layer 102 made of n-type GaAs having a thickness of 500 nm, the lower clad layer 103 made of n-type AlGaInP having a thickness of 1200 nm, the active layer 104 having the quantum well structure made of GaInP, the first upper clad layer 105 a made of p-type AlGaInP having a thickness of 400 nm, the etching stop layer 106 made of p-type GaInP having a thickness of 6 nm, the second upper clad layer 105 b made of p-type AlGaInP having a thickness of 600 nm, the intermediate layer 107 made of p-type GaInP having a thickness of 50 nm, and the contact layer 108 made of p-type GaAs having a thickness of 200 nm are stacked successively in an ascending order on the substrate 101 made of n-type GaAs by metal organic vapor phase epitaxy. [0039] Upper clad layers 105 composed of the first upper clad layer 105 a and the second upper clad layer 105 b have a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 101 . The etching stop layer 106 has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 set with respect to the substrate 101 . The impurity concentrations of the lower clad layer 103 and the upper clad layers 105 are set to values in the range of about 3×10 17 cm −3 to 1.5×10 18 cm −3 . [0040] Although the conductivity type of the upper clad layers 105 having the lattice mismatch is limited to the p-type in the case described herein above, the conductivity type of the upper clad layers 105 having the lattice mismatch may also be limited to the n-type. It is also possible to adopt a structure in which not only the upper clad layers 105 but also the lower clad layer 103 has a lattice mismatch. When each of the upper clad layers 105 and the lower clad layer 103 has a lattice mismatch, even though the conductivity type is either the n-type or the p-type, the lattice mismatch may either be substantially uniform or vary within the layer. [0041] The active layer 104 is formed by alternately stacking five well layers each made of GaInP having a thickness of 5 nm and five barrier layers each made of AlGaInP having a thickness of 5 nm. [0042] Although the present embodiment has described the case where the active layer 104 has the quantum well structure, it is also possible to construct the active layer 104 by using a bulk. The active layer 104 may have either the n-type conductivity or the p-type conductivity or may also be undoped, though the conductivity type thereof is not particularly shown. [0043] The etching stop layer 106 may have the n-type conductivity or may be undoped. Although the etching stop layer 106 is formed between the upper clad layers 105 (the first upper clad layer 105 a and the second upper clad layer 105 b ) in the description given herein above, the etching stop layer 106 may also be formed within the lower clad layer 103 and at any position provided that the etching stop layer 106 is formed in the upper clad layers 105 or in the lower clad layer 103 . The etching stop layer 106 is not limited to the single layer. A plurality of the etching stop layers 106 may also be provided. [0044] Next, as shown in FIG. 2B , a striped resist mask (not shown) having a width w (e.g., 3 μm) is formed and then etching is performed by a wet or dry etching method till the etching stop layer 106 is reached, thereby forming the striped ridge waveguide. The cross-sectional view shown in FIG. 2B is taken in a direction orthogonal to the direction in which the stripe extends. [0045] In the step illustrated in FIG. 2B , the etching stop layer 106 is formed in the upper clad layers 105 so that it is possible to strictly control etching conditions in forming the ridge waveguide by using a selective etching method. Specifically, the etching stop layer 106 has a negative lattice mismatch, as described above. That is, the proportion of Ga atoms to all the group III atoms is adjusted to be higher than that of In atoms (producing a Ga-rich state), whereby selectivity during the etching is improved. The selectivity during the etching is thus improved by the same mechanism according to which the GaAs layer having a lattice mismatch more negative than that of the AlGaAs layer is used as the etching stop layer because, of the GaAs layer and the AlGaAs layer each made of an AlGaAs material, the GaAs layer is lower in etching rate than the AlGaAs layer containing Al. Thus, in the step shown in FIG. 2B , the striped ridge waveguide is formed by performing selective etching using the etching stop layer 106 made of GaInP so that the management of the fabrication process is facilitated. This allows easy control of an equivalent refractivity difference and the achievement of a high production yield. [0046] Next, as shown in FIG. 2C , the current block layer 109 made of n-type GaAs having a thickness of 400 nm is formed over the upper surface of the etching stop layer 106 and the respective side surfaces of the second upper clad layer 105 b , the intermediate layer 107 , and the contact layer 108 . Subsequently, the p-type electrode 110 made of, e.g., Ti, Pt, and Au stacked in successive layers in an ascending order is formed over the contact layer 108 and the current block layer 109 . On the other hand, the n-type electrode 111 made of, e.g., AuGe, Ni, and Au stacked in successive layers in an ascending order is formed on the back surface of the substrate 101 . In this manner, the semiconductor laser device according to the first embodiment is formed. [0047] Referring to FIG. 3 , a description will be given herein below to the effect of the lattice mismatch of the etching stop layer 106 formed in the upper clad layers 105 (between the first upper clad layer 105 a and the second upper clad layer 105 b ). [0048] FIG. 3 shows the relationship between an aging time (hours) and a current degradation rate (%) in each of the following cases 3 a to 3 c where devices were fabricated differently in lots on a case-by-case basis and an aging test was performed on the fabricated devices at a temperature of 90° C. with the application of a current of 5 mW. Depending on the cases 3 a to 3 c , the upper clad layers 105 of the fabricated devices have the different lattices mismatches shown below and the etching stop layers 106 thereof have or do not have the lattice mismatch shown below. In the aging test, the devices which exhibited small increases in operating current were determined to be acceptable on a per lot basis. [0049] When a 1 represents the lattice constant of the semiconductor substrate and a 2 represents the lattice constant of the semiconductor layer as described above, the magnitude Δa/a of the lattice mismatch is given by Δa/a=(a 2 −a 1 )/a 1 . In the case 3 a , the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 with respect to the substrate 101 satisfies the relationship given by Δa/a=0. In the case 3 b , the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 satisfies the relationship given by Δa/a=5.0×10 −4 (i.e., the upper clad layers 105 have a lattice mismatch of 5.0×10 −4 ). By contrast, the case 3 c corresponds to the present embodiment in which the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 satisfies the relationship given by Δa/a=5.0×10 −4 (i.e., the upper clad layers 105 have a lattice mismatch of 5.0×10 −4 ) and the magnitude Δa/a of the lattice mismatch of the etching stop layer 106 satisfies the relationship given by Δa/a=−3.0×10 −4 (i.e., the etching stop layer 106 has a lattice mismatch of −3.0×10 −4 ). [0050] As shown in FIG. 3 , in the case 3 a , the operating current values increased within several tens of hours in the majority of the devices so that the passing rate of the test was approximately 0%. In the case 3 b , there were some devices in which the operating current values increased within several hundreds of hours so that the passing rate of the test was about 70%. By contrast, in the case 3 c corresponding to the present embodiment, the operating current values did not increase over a period of several thousands of hours or more in all the devices so that the passing rate of the test was about 100%. [0051] The reason for such experimental results is that, because the upper clad layers 105 have the positive lattice mismatch with respect to the substrate 101 , the lattice spacing of a crystal is reduced so that the diffusion of an impurity into the active layer 104 is prevented and, because the etching stop layer 106 has the negative lattice mismatch with respect to the substrate 101 , which is opposite to the positive lattice mismatch of the upper clad layers 105 , the distortions to the substrate 101 cancel out each other (i.e., the distortion resulting from the positive lattice mismatch and the distortion resulting from the negative lattice mismatch cancel out each other) and, therefore, the occurrence of a crystal defect is suppressed. [0052] FIG. 4 shows the result of reliability evaluation of each of devices fabricated by varying the lattice mismatch of the upper clad layers 105 and the lattice mismatch of the etching stop layer 104 . The reliability of each of the devices was evaluated at a temperature of 90° C. with the application of a current of 5 mW. [0053] From FIG. 4 , it will be understood that, in the case (the case 4 e shown in the upper part of FIG. 4 ) where the upper clad layers 105 have a positive lattice mismatch and the etching stop layer 106 has no lattice mismatch (or when no etching stop layer is provided), the reliability increases but, when the lattice mismatch is over or under a proper range, the diffusion of an impurity into the active layer 104 occurs to cause a crystal defect in the active layer 104 and degrade the reliability. By contrast, it will be understood that, when the upper clad layers 105 have a positive lattice mismatch and the etching stop layer 106 has a negative lattice mismatch (the cases 4 a to 4 d in the upper part of FIG. 4 ), the reliability greatly improves when each of the lattice mismatches is within a proper range. [0054] The present inventors have examined the proper ranges of the respective lattice mismatches of the upper clad layers 105 and the etching stop layer 106 by assuming that the average lifetime of the devices is represented by MTTF and a period of 5000 hours or more is a passing standard and found that the proper range of the lattice mismatch of the upper clad layers 105 is not less than 2.0×10 −4 and not more than 3.0×10 −3 and the proper range of the lattice mismatch of the etching stop layer 106 is not less than −2.0×10 −3 and not more than −2.0×10 −4 . [0055] A description will be given herein below to the impurity concentration of the upper clad layers 105 . [0056] In the present embodiment, the impurity concentration of the upper clad layers 105 is preferably not less than 3×10 17 cm −3 . [0057] By thus adjusting the impurity concentration of the upper clad layers 105 , it is possible to suppress the occurrence of a crystal defect in the active layer 104 and maintain an excellent temperature characteristic even in high-temperature condition at a temperature of not less than 90° C. As a result, the long term reliability can be guaranteed. [0058] So far, the present inventors have implemented an excellent temperature characteristic and excellent reliability in condition under a temperature of less than 75° C. However, when consideration is given to an application of an AlGaInP semiconductor laser device in higher-temperature condition (at a temperature of not less than 85° C.), such as an on-vehicle application, it is necessary to further improve the temperature characteristic. Although it has been found that the temperature characteristic can be improved by setting the impurity concentration to a value of not less than 3×10 17 cm −3 , reliability has had a problem because, at the stage at which only the upper clad layers 105 are allowed to have the lattice mismatch, a crystal defect occurs in the active layer 104 as shown in the foregoing cases 3 b and 4 e of FIGS. 3 and 4 . To solve the problem, the present inventors have formed the etching stop layer 106 having the negative lattice mismatch in the upper clad layers 105 , as described above, and thereby suppressed the occurrence of a crystal defect in the active layer. In addition, the present inventors have found that, by setting the impurity concentration of the upper clad layers 105 to a value of not less than 3×10 17 cm −3 , it is possible to guarantee the long term reliability, while maintaining an excellent temperature characteristic, even in high-temperature condition at a temperature of not less than 90° C. [0059] By thus fabricating the device such that the upper clad layers 105 have a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate 101 and the etching stop layer 106 has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate 101 , it is possible to suppress the occurrence of a crystal defect in the active layer 104 by preventing the diffusion of an impurity into the lower clad layer 103 and into the upper clad layers 105 and also maintain an excellent temperature characteristic even in high-temperature condition at a temperature of not less than 90° C. Accordingly, the reliability of the device can be improved. [0060] As a result, the semiconductor laser device according to the present embodiment allows easy control of impurity doping during the fabrication thereof and, even when impurity doping is performed at a position extremely close to the active layer 104 , the diffusion of the implanted impurity into the active layer 104 can be effectively prevented. This makes it possible to achieve a reduction in operating current by improving the light emission efficiency of the semiconductor laser device and improve the reliability of the device. [0061] Although the semiconductor layer having the negative lattice mismatch is only the etching stop layer 106 in the case described herein above, the same effects as described above are obtainable even when a semiconductor layer other than the etching stop layer 106 has a negative lattice mismatch. FIG. 5 shows the results of an experiment performed under combined conditions for the reliability evaluation of semiconductor laser devices fabricated to have clad layers with a positive lattice mismatch, wherein the average lifetime of the devices is represented by MTTF and a period of 5000 hours or more is a passing standard. In some of the fabricated devices, the etching stop layers 106 had a negative lattice mismatch. In the others, semiconductor layers other than the etching stoppers 106 had a negative lattice mismatch. As is obvious from FIG. 5 , the reliability of each of the devices improved beyond the passing standard when at least one semiconductor layer having a negative lattice mismatch was included in the clad layers having a positive lattice mismatch. Although the same reliability experiment was performed on the device in which the etching stop layer having a positive lattice mismatch was formed within the clad layer having a positive lattice mismatch, it was proved that the reliability of the device did not improve. Therefore, it is evident that the formation of the semiconductor layer having a negative lattice mismatch in the clad layer having a positive lattice mismatch is preferable. Variation of Embodiment 1 [0062] A semiconductor laser device according to a variation of the first embodiment is different from the semiconductor laser device according to the first embodiment described above only in the structure of the active layer 104 and is the same in the other respects. [0063] Specifically, the semiconductor laser device according to the present variation is the same as in the first embodiment in that the active layer 104 is formed by alternately stacking the five well layers each made of GaInP having a thickness of 5 nm and the five barrier layers made of AlGaInP having a thickness of 5 nm. The semiconductor laser device according to present the variation is characterized in that the active layer 104 has a self-sustained pulsation characteristic, the well layers made of GaInP composing the active layer 104 have a positive lattice mismatch of not less than 3.0×10 −4 and not more than 5.0×10 −3 , and the barrier layer made of AlGaInP is lattice-matched to the substrate 101 . [0064] In the semiconductor laser device according to the present variation, the total number of the well layers made of GaInP is large and therefore, even in the semiconductor laser device having the self-sustained pulsation characteristic which increases the operating current in high-temperature condition, the same effects as obtained in the first embodiment are obtainable. In particular, when the total combined film thickness of the well layers is not less than 20 nm, the arrangement was proved to be effective in improving the reliability. Embodiment 2 [0065] FIG. 6 is a cross-sectional view of a semiconductor laser device according to the second embodiment of the present invention. [0066] As shown in FIG. 6 , a buffer layer 502 made of n-type GaAs having a thickness of 500 nm, a lower clad layer 503 made of n-type AlGaInP having a thickness of 1200 nm, an active layer 504 having a quantum well structure made of GaInP, a lightly doped upper clad layer 505 made of p-type AlGaInP having a thickness of 50 nm, a first heavily doped upper clad layer 506 a made of p-type AlGaInP having a thickness of 350 nm, an etching stop layer 507 made of p-type GaInP having a thickness of 6 nm, a second heavily doped upper clad layer 506 b made of p-type AlGaInP having a thickness of 600 nm, an intermediate layer 508 made of p-type GaInP having a thickness of 50 nm, and a contact layer 509 made of p-type GaAs having a thickness of 200 nm are formed successively in an ascending order on a substrate 501 made of n-type GaAs. The second heavily doped upper clad layer 506 b , the intermediate layer 508 , and the contact layer 509 constitute a striped ridge waveguide in the same manner as in the first embodiment and is formed by using the etching selectivity of the etching stop layer 507 . A current block layer 510 made of n-type GaAs having a thickness of 400 nm is further formed over the side surfaces of the striped ridge waveguide and the upper surface of the etching stop layer 507 . A p-type electrode 511 is formed over the contact layer 509 and the current block layer 510 , while an n-type electrode 512 is formed on the back surface of the substrate 501 . [0067] Each of the lightly doped upper clad layer 505 and heavily doped upper clad layers 506 composed of the first and second heavily doped upper clad layers 506 a and 506 b has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 501 . The etching stop layer 507 is lattice-matched to the substrate 501 . The impurity concentrations of the lower clad layer 503 , the lightly doped upper clad layer 505 , and the heavily doped upper clad layers 506 are adjusted to values in the respective ranges of about 3×10 17 cm −3 to 1.5×10 18 cm −3 , about 1×10 17 cm −3 to 3×10 17 cm −3 , and about 4×10 17 cm −3 to 1.5×10 18 cm −3 . [0068] Although the present embodiment has described the case where the conductivity type of each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 is limited to the p-type, the conductivity type of each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 may also be limited to the n-type. It is also possible to adopt a structure in which not only the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 but also the lower clad layer 503 has a lattice mismatch. When each of the lightly doped upper clad layer 505 , the heavily doped upper clad layers 506 , and the lower clad layer 503 has a lattice mismatch, the lattice mismatch may either be substantially uniform or vary within the layer. [0069] The etching stop layer 507 may also be undoped. [0070] In the semiconductor laser device according to the present embodiment thus constructed, each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 501 and, in addition, the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 have an impurity concentration difference therebetween. As a result, the same effects as obtained in the first embodiment are obtainable without forming a semiconductor layer having a negative lattice mismatch in the upper clad layers ( 505 and 506 ). However, it is also possible to obtain the same effects as obtained in the first embodiment even when the semiconductor layer having the negative lattice mismatch is formed in the upper clad layers ( 505 and 506 ). [0071] Although the specific description has been given to the first and second embodiments of the present invention, the present invention is not limited to the embodiments described above and various modifications can be made based on the technical idea of the present invention. For example, the values, the device structure, the substrate, the process, the growth method, and the like mentioned in each of the embodiments described above are only exemplary. It is also possible to use values, a device structure, a process, a growth method, and the like which are different from those used in the embodiment. Specifically, although metal organic vapor phase epitaxy has been used in the embodiments described above, it is also possible to use another epitaxial growth method such as, e.g., molecular beam epitaxy. Although each of the foregoing embodiments has described only the case where a red semiconductor laser device is an embodiment of the semiconductor laser device according to the present invention, the present invention is also applicable to a blue semiconductor laser device, a red/infrared dual-wavelength semiconductor laser device, or the like. The present invention is also applicable to an AlGaAs semiconductor light emitting device, a semiconductor light emitting device using a group II-VI compound semiconductor, a light emitting device using a nitride group III-V compound semiconductor, or the like. [0072] The semiconductor laser device and the fabrication therefor according to the present invention allow an improvement in the reliability of the device. In addition, because the semiconductor laser device has a structure easy to fabricate, the industrial applicability thereof is high in terms of allowing an improvement in the production yield of the device. In particular, the semiconductor laser device and the fabrication method therefor according to the present invention are highly usable to a laser of which high reliability is required in high-temperature condition, such as in an on-vehicle application.
A semiconductor laser device has a multilayer structure including a first clad layer, an active layer, and a second clad layer stacked successively on a semiconductor substrate in order of increasing distance from the semiconductor substrate. At least one of the first clad layer and the second clad layer has a compressive distortion with respect to the semiconductor substrate. At least one of the first clad layer and the second clad layer includes a semiconductor layer having a tensile distortion with respect to the semiconductor substrate.
Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function.
[ "BACKGROUND OF THE INVENTION [0001] The present invention relates to a semiconductor laser device and a fabrication method therefor, and, more particularly, to a semiconductor laser device which can be used preferably as a light source for an optical disk apparatus or the like and a fabrication method therefor.", "[0002] In a semiconductor laser device, particularly in an AlGaInP semiconductor laser device in which the heterojunction between an active layer and a clad layer cannot have a sufficiently high barrier, a technology for controlling impurity doping has an important influence on the characteristics of the device.", "[0003] Specifically, there has been conventionally known an AlGaInP semiconductor laser device wherein the clad layer adjacent to the active layer is left undoped by controlling the position at which impurity doping is performed during the fabrication thereof.", "The conventional AlGaInP semiconductor laser having such a structure is advantageous in that the diffusion of the impurity from the clad layer into the active layer can be prevented.", "[0004] However, the conventional AlGaInP semiconductor laser device described above has the problem that, when the position at which impurity is performed is further away from the active layer, the efficiency of conversion from an injected current to light deteriorates so that the operating current thereof increases.", "Conversely, when the position at which impurity doping is performed is closer to the active layer, the problem occurs that the diffusion of the impurity reaches the interior of the active layer due to a thermal process or the like and the deterioration of the device occurs within a short time of about several hours to reduce the lifetime of the device and consequently degrade the reliability of the device.", "[0005] Thus, in the conventional AlGaInP semiconductor laser, it has been necessary to control impurity doping with high accuracy so that considerable difficulty has been encountered in the fabrication thereof.", "[0006] To reduce the difficulty, Japanese Laid-Open Patent Publication No. HEI 11-87831 proposes a semiconductor laser device having a structure which can not only prevent the diffusion of an impurity into the active layer but also improve light emission efficiency, reduce the operating current, and suppress the reliability degradation of the device by controlling the lattice mismatch of the clad layer with respect to a semiconductor substrate.", "[0007] However, the semiconductor laser device having the structure which controls the lattice mismatch of the clad layer with respect to the semiconductor substrate described above has had the problem that a crystal defect occurs in the active layer and the long term reliability of the device cannot be guaranteed, though the impurity diffusion into the active layer can be prevented.", "In addition, the semiconductor laser device also has had the problem that the setting of process conditions in forming a ridge waveguide is difficult and the production yield thereof is low.", "SUMMARY OF THE INVENTION [0008] In view of the foregoing, it is therefore an object of the present invention to provide a semiconductor laser device having a structure which allows an improvement in the reliability of the device and a fabrication method therefor.", "Another object of the present invention is to provide a laser device having a structure which allows easy formation of a ridge waveguide and a fabrication method for a laser device in which a ridge waveguide can be easily formed.", "[0009] As a result of conducting intensive studies, the present inventors have found that, when a clad layer has a unidirectional distortion, which is either a compressive distortion or a tensile distortion, with respect to a semiconductor substrate, a crystal defect occurs in an active layer and degrades the reliability of a device.", "The present invention has been achieved in view of the foregoing findings and provides a semiconductor laser device comprising a clad layer having both of the compressive distortion and the tensile distortion.", "[0010] Specifically, a semiconductor laser device according to a first aspect of the present invention is a semiconductor laser device having a multilayer structure comprising a first clad layer, an active layer, and a second clad layer stacked successively on a semiconductor substrate in order of increasing distance from the semiconductor substrate, wherein at least one of the first clad layer and the second clad layer has a compressive distortion with respect to the semiconductor substrate and at least one of the first clad layer and the second clad layer includes a semiconductor layer having a tensile distortion with respect to the semiconductor substrate.", "[0011] In the semiconductor laser device according to the first aspect of the present invention, at least one of the first and second clad layers has the compressive distortion with respect to the semiconductor substrate so that the lattice spacing of a crystal is reduced.", "As a result, it is possible to effectively prevent the diffusion of an impurity into the active layer.", "In addition, at least one of the first and second clad layers having the compressive distortion includes therein the semiconductor layer having the tensile distortion with respect to the semiconductor substrate so that the compressive distortion and the tensile distortion each with respect to the semiconductor substrate cancel out each other.", "This suppresses the occurrence of a crystal defect in the active layer and improves the reliability of the semiconductor laser device.", "[0012] The compressive distortion with respect to the semiconductor substrate indicates herein that the magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is positive.", "The tensile distortion with respect to the semiconductor substrate indicates herein that the magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is negative.", "The magnitude Δa/a of the lattice mismatch of the semiconductor layer with respect to the semiconductor substrate is given by Δa/a=(a 2 −a 1 )/a 1 wherein a 1 represents the lattice constant of the semiconductor substrate and a 2 represents the lattice constant of the semiconductor layer.", "[0013] Preferably, in the semiconductor laser device according to the first aspect of the present invention, at least one of the first clad layer and the second clad layer having the compressive distortion has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate and the semiconductor layer having the tensile distortion has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate.", "According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented.", "[0014] Preferably, in the semiconductor laser device according to the first aspect of the present invention, the second clad layer has the semiconductor layer having the tensile distortion and the semiconductor layer having the tensile distortion functions as an etching stop layer when a ridge portion is formed in the second clad layer by etching.", "[0015] According to the preferred embodiment, it becomes possible to easily form the ridge portion in the second clad layer by using the semiconductor layer functioning as the etching stop layer.", "As a result, the production yield of the device of which the long term reliability is guaranteed is improved.", "[0016] A semiconductor laser device according to a second aspect of the present invention is a semiconductor laser device having a multilayer structure comprising a first clad layer, an active layer, and a second clad layer stacked successively on a semiconductor substrate in order of increasing distance from the semiconductor substrate, wherein at least one of the first clad layer and the second clad layer has a compressive distortion with respect to the semiconductor substrate and at least one of the first clad layer and the second clad layer has a heavily doped impurity region containing an impurity at a relatively high concentration and a lightly doped impurity region containing an impurity at a relatively low concentration.", "[0017] In the semiconductor laser device according to the second aspect of the present invention, at least one of the first and second clad layers has the compressive distortion with respect to the semiconductor substrate so that the lattice spacing of a crystal is reduced.", "As a result, it is possible to effectively prevent the diffusion of an impurity into the active layer.", "In addition, at least one of the first and second clad layers has an impurity concentration difference therein so that the occurrence of a crystal defect in the active layer is suppressed and the reliability of the semiconductor laser device is improved.", "[0018] Preferably, in the semiconductor laser device according to the second aspect of the present invention, the heavily doped impurity region is formed at a position further away from the active layer than a position at which the lightly doped impurity region is formed and the lightly doped impurity region is formed at a position closer to the active layer than at the position at which the heavily doped impurity region is formed.", "According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented.", "[0019] Preferably, in the semiconductor laser device according to the second aspect of the present invention, at least one of the first clad layer and the second clad layer includes a semiconductor layer having a tensile distortion with respect to the semiconductor substrate.", "According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented.", "[0020] Preferably, in the semiconductor laser device according to the second aspect of the present invention, at least one of the first clad layer and the second clad layer having the compressive distortion has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate.", "According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented.", "[0021] Preferably, in the semiconductor laser device according to the second aspect of the present invention, the semiconductor layer having the tensile distortion has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate.", "According to the preferred embodiment, the diffusion of an impurity into the active layer can be reliably prevented.", "[0022] Preferably, in the semiconductor laser device according to the second aspect of the present invention, a well layer composing the active layer has the compressive distortion with respect to the semiconductor substrate and a film thickness of not less than 20 nm.", "The preferred embodiment is effective in improving the reliability of the device.", "[0023] Even when the semiconductor laser device according to the second aspect of the present invention has a self-sustained pulsation characteristic which increases the operating current in high temperature condition, the reliability of the device is improved.", "[0024] A method for fabricating a semiconductor laser device according to an aspect of the present invention comprises the steps of: forming, on a semiconductor substrate, a first clad layer having a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate;", "forming an active layer on the first clad layer;", "forming, on the active layer, a second clad layer having a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate and including therein a semiconductor layer having a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate;", "and etching the second clad layer using the semiconductor layer as an etching stop layer to form a ridge portion therein.", "[0025] In accordance with the method for fabricating a semiconductor laser device according to the aspect of the present invention, it is possible to suppress the occurrence of a crystal defect in the active layer, easily fabricate the device of which the long term reliability is guaranteed, and improve the production yield thereof by using the etching stop layer.", "[0026] According to the present invention, a semiconductor laser device having a structure with excellent reliability and a fabrication therefor can be provided.", "BRIEF DESCRIPTION OF THE DRAWINGS [0027] FIG. 1 is a cross-sectional view showing a structure of a semiconductor laser device according to a first embodiment of the present invention;", "[0028] FIGS. 2A to 2C are cross-sectional views illustrating a method for fabricating the semiconductor laser device according to the first embodiment in the order in which the process steps thereof are performed;", "[0029] FIG. 3 is a graph showing the relationship between an aging time and a current degradation rate when an aging test is performed on the semiconductor laser device according to the first embodiment;", "[0030] FIG. 4 is a graph showing the relationship between the lattice mismatch of clad layers and reliability in the semiconductor laser device according to the first embodiment;", "[0031] FIG. 5 is a list of the results of an experiment performed under combined conditions for the reliability evaluation of semiconductor laser devices having different structures in the first embodiment;", "and [0032] FIG. 6 is a cross-sectional view showing a structure of a semiconductor laser device according to a second embodiment of the present invention.", "DETAILED DESCRIPTION OF THE INVENTION [0033] Referring now to the drawings, the individual embodiments of the present invention will be described herein below.", "Embodiment 1 [0034] FIG. 1 is a cross-sectional view of a semiconductor laser device according to the first embodiment of the present invention.", "[0035] As shown in FIG. 1 , a buffer layer 102 made of n-type GaAs having a thickness of 500 nm, a lower clad layer 103 made of n-type AlGaInP having a thickness of 1200 nm, an active layer 104 having a quantum well structure made of GaInP, a first upper clad layer 105 a made of p-type AlGaInP having a thickness of 400 nm, an etching stop layer 106 made of p-type GaInP having a thickness of 6 nm, a second upper clad layer 105 b made of p-type AlGaInP having a thickness of 600 nm, an intermediate layer 107 made of p-type GaInP having a thickness of 50 nm, and a contact layer 108 made of p-type GaAs having a thickness of 200 nm are formed successively in an ascending order on a substrate 101 made of n-type GaAs.", "The second upper clad layer 105 b , the intermediate layer 107 , and the contact layer 108 constitute a striped ridge waveguide.", "A current block layer 109 made of n-type GaAs having a thickness of 400 nm is further formed over the side surfaces of the striped ridge waveguide and the upper surface of the etching stop layer 106 .", "A p-type electrode 110 is formed over the contact layer 108 and the current block layer 109 , while an n-type electrode 111 is formed on the back surface of the substrate 101 .", "[0036] A description will be given herein below to a specific method for fabricating the semiconductor layer according to the first embodiment thus constructed.", "[0037] FIGS. 2A to 2C are cross-sectional views for illustrating the process steps of the method for fabricating the semiconductor laser device according to the first embodiment.", "[0038] First, as shown in FIG. 2A , the buffer layer 102 made of n-type GaAs having a thickness of 500 nm, the lower clad layer 103 made of n-type AlGaInP having a thickness of 1200 nm, the active layer 104 having the quantum well structure made of GaInP, the first upper clad layer 105 a made of p-type AlGaInP having a thickness of 400 nm, the etching stop layer 106 made of p-type GaInP having a thickness of 6 nm, the second upper clad layer 105 b made of p-type AlGaInP having a thickness of 600 nm, the intermediate layer 107 made of p-type GaInP having a thickness of 50 nm, and the contact layer 108 made of p-type GaAs having a thickness of 200 nm are stacked successively in an ascending order on the substrate 101 made of n-type GaAs by metal organic vapor phase epitaxy.", "[0039] Upper clad layers 105 composed of the first upper clad layer 105 a and the second upper clad layer 105 b have a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 101 .", "The etching stop layer 106 has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 set with respect to the substrate 101 .", "The impurity concentrations of the lower clad layer 103 and the upper clad layers 105 are set to values in the range of about 3×10 17 cm −3 to 1.5×10 18 cm −3 .", "[0040] Although the conductivity type of the upper clad layers 105 having the lattice mismatch is limited to the p-type in the case described herein above, the conductivity type of the upper clad layers 105 having the lattice mismatch may also be limited to the n-type.", "It is also possible to adopt a structure in which not only the upper clad layers 105 but also the lower clad layer 103 has a lattice mismatch.", "When each of the upper clad layers 105 and the lower clad layer 103 has a lattice mismatch, even though the conductivity type is either the n-type or the p-type, the lattice mismatch may either be substantially uniform or vary within the layer.", "[0041] The active layer 104 is formed by alternately stacking five well layers each made of GaInP having a thickness of 5 nm and five barrier layers each made of AlGaInP having a thickness of 5 nm.", "[0042] Although the present embodiment has described the case where the active layer 104 has the quantum well structure, it is also possible to construct the active layer 104 by using a bulk.", "The active layer 104 may have either the n-type conductivity or the p-type conductivity or may also be undoped, though the conductivity type thereof is not particularly shown.", "[0043] The etching stop layer 106 may have the n-type conductivity or may be undoped.", "Although the etching stop layer 106 is formed between the upper clad layers 105 (the first upper clad layer 105 a and the second upper clad layer 105 b ) in the description given herein above, the etching stop layer 106 may also be formed within the lower clad layer 103 and at any position provided that the etching stop layer 106 is formed in the upper clad layers 105 or in the lower clad layer 103 .", "The etching stop layer 106 is not limited to the single layer.", "A plurality of the etching stop layers 106 may also be provided.", "[0044] Next, as shown in FIG. 2B , a striped resist mask (not shown) having a width w (e.g., 3 μm) is formed and then etching is performed by a wet or dry etching method till the etching stop layer 106 is reached, thereby forming the striped ridge waveguide.", "The cross-sectional view shown in FIG. 2B is taken in a direction orthogonal to the direction in which the stripe extends.", "[0045] In the step illustrated in FIG. 2B , the etching stop layer 106 is formed in the upper clad layers 105 so that it is possible to strictly control etching conditions in forming the ridge waveguide by using a selective etching method.", "Specifically, the etching stop layer 106 has a negative lattice mismatch, as described above.", "That is, the proportion of Ga atoms to all the group III atoms is adjusted to be higher than that of In atoms (producing a Ga-rich state), whereby selectivity during the etching is improved.", "The selectivity during the etching is thus improved by the same mechanism according to which the GaAs layer having a lattice mismatch more negative than that of the AlGaAs layer is used as the etching stop layer because, of the GaAs layer and the AlGaAs layer each made of an AlGaAs material, the GaAs layer is lower in etching rate than the AlGaAs layer containing Al.", "Thus, in the step shown in FIG. 2B , the striped ridge waveguide is formed by performing selective etching using the etching stop layer 106 made of GaInP so that the management of the fabrication process is facilitated.", "This allows easy control of an equivalent refractivity difference and the achievement of a high production yield.", "[0046] Next, as shown in FIG. 2C , the current block layer 109 made of n-type GaAs having a thickness of 400 nm is formed over the upper surface of the etching stop layer 106 and the respective side surfaces of the second upper clad layer 105 b , the intermediate layer 107 , and the contact layer 108 .", "Subsequently, the p-type electrode 110 made of, e.g., Ti, Pt, and Au stacked in successive layers in an ascending order is formed over the contact layer 108 and the current block layer 109 .", "On the other hand, the n-type electrode 111 made of, e.g., AuGe, Ni, and Au stacked in successive layers in an ascending order is formed on the back surface of the substrate 101 .", "In this manner, the semiconductor laser device according to the first embodiment is formed.", "[0047] Referring to FIG. 3 , a description will be given herein below to the effect of the lattice mismatch of the etching stop layer 106 formed in the upper clad layers 105 (between the first upper clad layer 105 a and the second upper clad layer 105 b ).", "[0048] FIG. 3 shows the relationship between an aging time (hours) and a current degradation rate (%) in each of the following cases 3 a to 3 c where devices were fabricated differently in lots on a case-by-case basis and an aging test was performed on the fabricated devices at a temperature of 90° C. with the application of a current of 5 mW.", "Depending on the cases 3 a to 3 c , the upper clad layers 105 of the fabricated devices have the different lattices mismatches shown below and the etching stop layers 106 thereof have or do not have the lattice mismatch shown below.", "In the aging test, the devices which exhibited small increases in operating current were determined to be acceptable on a per lot basis.", "[0049] When a 1 represents the lattice constant of the semiconductor substrate and a 2 represents the lattice constant of the semiconductor layer as described above, the magnitude Δa/a of the lattice mismatch is given by Δa/a=(a 2 −a 1 )/a 1 .", "In the case 3 a , the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 with respect to the substrate 101 satisfies the relationship given by Δa/a=0.", "In the case 3 b , the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 satisfies the relationship given by Δa/a=5.0×10 −4 (i.e., the upper clad layers 105 have a lattice mismatch of 5.0×10 −4 ).", "By contrast, the case 3 c corresponds to the present embodiment in which the magnitude Δa/a of the lattice mismatch of the upper clad layers 105 satisfies the relationship given by Δa/a=5.0×10 −4 (i.e., the upper clad layers 105 have a lattice mismatch of 5.0×10 −4 ) and the magnitude Δa/a of the lattice mismatch of the etching stop layer 106 satisfies the relationship given by Δa/a=−3.0×10 −4 (i.e., the etching stop layer 106 has a lattice mismatch of −3.0×10 −4 ).", "[0050] As shown in FIG. 3 , in the case 3 a , the operating current values increased within several tens of hours in the majority of the devices so that the passing rate of the test was approximately 0%.", "In the case 3 b , there were some devices in which the operating current values increased within several hundreds of hours so that the passing rate of the test was about 70%.", "By contrast, in the case 3 c corresponding to the present embodiment, the operating current values did not increase over a period of several thousands of hours or more in all the devices so that the passing rate of the test was about 100%.", "[0051] The reason for such experimental results is that, because the upper clad layers 105 have the positive lattice mismatch with respect to the substrate 101 , the lattice spacing of a crystal is reduced so that the diffusion of an impurity into the active layer 104 is prevented and, because the etching stop layer 106 has the negative lattice mismatch with respect to the substrate 101 , which is opposite to the positive lattice mismatch of the upper clad layers 105 , the distortions to the substrate 101 cancel out each other (i.e., the distortion resulting from the positive lattice mismatch and the distortion resulting from the negative lattice mismatch cancel out each other) and, therefore, the occurrence of a crystal defect is suppressed.", "[0052] FIG. 4 shows the result of reliability evaluation of each of devices fabricated by varying the lattice mismatch of the upper clad layers 105 and the lattice mismatch of the etching stop layer 104 .", "The reliability of each of the devices was evaluated at a temperature of 90° C. with the application of a current of 5 mW.", "[0053] From FIG. 4 , it will be understood that, in the case (the case 4 e shown in the upper part of FIG. 4 ) where the upper clad layers 105 have a positive lattice mismatch and the etching stop layer 106 has no lattice mismatch (or when no etching stop layer is provided), the reliability increases but, when the lattice mismatch is over or under a proper range, the diffusion of an impurity into the active layer 104 occurs to cause a crystal defect in the active layer 104 and degrade the reliability.", "By contrast, it will be understood that, when the upper clad layers 105 have a positive lattice mismatch and the etching stop layer 106 has a negative lattice mismatch (the cases 4 a to 4 d in the upper part of FIG. 4 ), the reliability greatly improves when each of the lattice mismatches is within a proper range.", "[0054] The present inventors have examined the proper ranges of the respective lattice mismatches of the upper clad layers 105 and the etching stop layer 106 by assuming that the average lifetime of the devices is represented by MTTF and a period of 5000 hours or more is a passing standard and found that the proper range of the lattice mismatch of the upper clad layers 105 is not less than 2.0×10 −4 and not more than 3.0×10 −3 and the proper range of the lattice mismatch of the etching stop layer 106 is not less than −2.0×10 −3 and not more than −2.0×10 −4 .", "[0055] A description will be given herein below to the impurity concentration of the upper clad layers 105 .", "[0056] In the present embodiment, the impurity concentration of the upper clad layers 105 is preferably not less than 3×10 17 cm −3 .", "[0057] By thus adjusting the impurity concentration of the upper clad layers 105 , it is possible to suppress the occurrence of a crystal defect in the active layer 104 and maintain an excellent temperature characteristic even in high-temperature condition at a temperature of not less than 90° C. As a result, the long term reliability can be guaranteed.", "[0058] So far, the present inventors have implemented an excellent temperature characteristic and excellent reliability in condition under a temperature of less than 75° C. However, when consideration is given to an application of an AlGaInP semiconductor laser device in higher-temperature condition (at a temperature of not less than 85° C.), such as an on-vehicle application, it is necessary to further improve the temperature characteristic.", "Although it has been found that the temperature characteristic can be improved by setting the impurity concentration to a value of not less than 3×10 17 cm −3 , reliability has had a problem because, at the stage at which only the upper clad layers 105 are allowed to have the lattice mismatch, a crystal defect occurs in the active layer 104 as shown in the foregoing cases 3 b and 4 e of FIGS. 3 and 4 .", "To solve the problem, the present inventors have formed the etching stop layer 106 having the negative lattice mismatch in the upper clad layers 105 , as described above, and thereby suppressed the occurrence of a crystal defect in the active layer.", "In addition, the present inventors have found that, by setting the impurity concentration of the upper clad layers 105 to a value of not less than 3×10 17 cm −3 , it is possible to guarantee the long term reliability, while maintaining an excellent temperature characteristic, even in high-temperature condition at a temperature of not less than 90° C. [0059] By thus fabricating the device such that the upper clad layers 105 have a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 with respect to the semiconductor substrate 101 and the etching stop layer 106 has a lattice mismatch of not less than −2.0×10 −3 and not more than −2.0×10 −4 with respect to the semiconductor substrate 101 , it is possible to suppress the occurrence of a crystal defect in the active layer 104 by preventing the diffusion of an impurity into the lower clad layer 103 and into the upper clad layers 105 and also maintain an excellent temperature characteristic even in high-temperature condition at a temperature of not less than 90° C. Accordingly, the reliability of the device can be improved.", "[0060] As a result, the semiconductor laser device according to the present embodiment allows easy control of impurity doping during the fabrication thereof and, even when impurity doping is performed at a position extremely close to the active layer 104 , the diffusion of the implanted impurity into the active layer 104 can be effectively prevented.", "This makes it possible to achieve a reduction in operating current by improving the light emission efficiency of the semiconductor laser device and improve the reliability of the device.", "[0061] Although the semiconductor layer having the negative lattice mismatch is only the etching stop layer 106 in the case described herein above, the same effects as described above are obtainable even when a semiconductor layer other than the etching stop layer 106 has a negative lattice mismatch.", "FIG. 5 shows the results of an experiment performed under combined conditions for the reliability evaluation of semiconductor laser devices fabricated to have clad layers with a positive lattice mismatch, wherein the average lifetime of the devices is represented by MTTF and a period of 5000 hours or more is a passing standard.", "In some of the fabricated devices, the etching stop layers 106 had a negative lattice mismatch.", "In the others, semiconductor layers other than the etching stoppers 106 had a negative lattice mismatch.", "As is obvious from FIG. 5 , the reliability of each of the devices improved beyond the passing standard when at least one semiconductor layer having a negative lattice mismatch was included in the clad layers having a positive lattice mismatch.", "Although the same reliability experiment was performed on the device in which the etching stop layer having a positive lattice mismatch was formed within the clad layer having a positive lattice mismatch, it was proved that the reliability of the device did not improve.", "Therefore, it is evident that the formation of the semiconductor layer having a negative lattice mismatch in the clad layer having a positive lattice mismatch is preferable.", "Variation of Embodiment 1 [0062] A semiconductor laser device according to a variation of the first embodiment is different from the semiconductor laser device according to the first embodiment described above only in the structure of the active layer 104 and is the same in the other respects.", "[0063] Specifically, the semiconductor laser device according to the present variation is the same as in the first embodiment in that the active layer 104 is formed by alternately stacking the five well layers each made of GaInP having a thickness of 5 nm and the five barrier layers made of AlGaInP having a thickness of 5 nm.", "The semiconductor laser device according to present the variation is characterized in that the active layer 104 has a self-sustained pulsation characteristic, the well layers made of GaInP composing the active layer 104 have a positive lattice mismatch of not less than 3.0×10 −4 and not more than 5.0×10 −3 , and the barrier layer made of AlGaInP is lattice-matched to the substrate 101 .", "[0064] In the semiconductor laser device according to the present variation, the total number of the well layers made of GaInP is large and therefore, even in the semiconductor laser device having the self-sustained pulsation characteristic which increases the operating current in high-temperature condition, the same effects as obtained in the first embodiment are obtainable.", "In particular, when the total combined film thickness of the well layers is not less than 20 nm, the arrangement was proved to be effective in improving the reliability.", "Embodiment 2 [0065] FIG. 6 is a cross-sectional view of a semiconductor laser device according to the second embodiment of the present invention.", "[0066] As shown in FIG. 6 , a buffer layer 502 made of n-type GaAs having a thickness of 500 nm, a lower clad layer 503 made of n-type AlGaInP having a thickness of 1200 nm, an active layer 504 having a quantum well structure made of GaInP, a lightly doped upper clad layer 505 made of p-type AlGaInP having a thickness of 50 nm, a first heavily doped upper clad layer 506 a made of p-type AlGaInP having a thickness of 350 nm, an etching stop layer 507 made of p-type GaInP having a thickness of 6 nm, a second heavily doped upper clad layer 506 b made of p-type AlGaInP having a thickness of 600 nm, an intermediate layer 508 made of p-type GaInP having a thickness of 50 nm, and a contact layer 509 made of p-type GaAs having a thickness of 200 nm are formed successively in an ascending order on a substrate 501 made of n-type GaAs.", "The second heavily doped upper clad layer 506 b , the intermediate layer 508 , and the contact layer 509 constitute a striped ridge waveguide in the same manner as in the first embodiment and is formed by using the etching selectivity of the etching stop layer 507 .", "A current block layer 510 made of n-type GaAs having a thickness of 400 nm is further formed over the side surfaces of the striped ridge waveguide and the upper surface of the etching stop layer 507 .", "A p-type electrode 511 is formed over the contact layer 509 and the current block layer 510 , while an n-type electrode 512 is formed on the back surface of the substrate 501 .", "[0067] Each of the lightly doped upper clad layer 505 and heavily doped upper clad layers 506 composed of the first and second heavily doped upper clad layers 506 a and 506 b has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 501 .", "The etching stop layer 507 is lattice-matched to the substrate 501 .", "The impurity concentrations of the lower clad layer 503 , the lightly doped upper clad layer 505 , and the heavily doped upper clad layers 506 are adjusted to values in the respective ranges of about 3×10 17 cm −3 to 1.5×10 18 cm −3 , about 1×10 17 cm −3 to 3×10 17 cm −3 , and about 4×10 17 cm −3 to 1.5×10 18 cm −3 .", "[0068] Although the present embodiment has described the case where the conductivity type of each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 is limited to the p-type, the conductivity type of each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 may also be limited to the n-type.", "It is also possible to adopt a structure in which not only the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 but also the lower clad layer 503 has a lattice mismatch.", "When each of the lightly doped upper clad layer 505 , the heavily doped upper clad layers 506 , and the lower clad layer 503 has a lattice mismatch, the lattice mismatch may either be substantially uniform or vary within the layer.", "[0069] The etching stop layer 507 may also be undoped.", "[0070] In the semiconductor laser device according to the present embodiment thus constructed, each of the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 has a lattice mismatch of not less than 2.0×10 −4 and not more than 3.0×10 −3 set with respect to the substrate 501 and, in addition, the lightly doped upper clad layer 505 and the heavily doped upper clad layers 506 have an impurity concentration difference therebetween.", "As a result, the same effects as obtained in the first embodiment are obtainable without forming a semiconductor layer having a negative lattice mismatch in the upper clad layers ( 505 and 506 ).", "However, it is also possible to obtain the same effects as obtained in the first embodiment even when the semiconductor layer having the negative lattice mismatch is formed in the upper clad layers ( 505 and 506 ).", "[0071] Although the specific description has been given to the first and second embodiments of the present invention, the present invention is not limited to the embodiments described above and various modifications can be made based on the technical idea of the present invention.", "For example, the values, the device structure, the substrate, the process, the growth method, and the like mentioned in each of the embodiments described above are only exemplary.", "It is also possible to use values, a device structure, a process, a growth method, and the like which are different from those used in the embodiment.", "Specifically, although metal organic vapor phase epitaxy has been used in the embodiments described above, it is also possible to use another epitaxial growth method such as, e.g., molecular beam epitaxy.", "Although each of the foregoing embodiments has described only the case where a red semiconductor laser device is an embodiment of the semiconductor laser device according to the present invention, the present invention is also applicable to a blue semiconductor laser device, a red/infrared dual-wavelength semiconductor laser device, or the like.", "The present invention is also applicable to an AlGaAs semiconductor light emitting device, a semiconductor light emitting device using a group II-VI compound semiconductor, a light emitting device using a nitride group III-V compound semiconductor, or the like.", "[0072] The semiconductor laser device and the fabrication therefor according to the present invention allow an improvement in the reliability of the device.", "In addition, because the semiconductor laser device has a structure easy to fabricate, the industrial applicability thereof is high in terms of allowing an improvement in the production yield of the device.", "In particular, the semiconductor laser device and the fabrication method therefor according to the present invention are highly usable to a laser of which high reliability is required in high-temperature condition, such as in an on-vehicle application." ]
BACKGROUND OF THE INVENTION This invention relates to an insulating protective material effective for protecting electronic and electrical components such as electronic elements and the like. More particularly it relates to protective material used for protecting elements, contacts, etc. of IC packages and electronic devices including the IC packages used as electronic materials or electronic and electrical components such as electronic elements, e.g., indicator tubes. According to this invention there is provided an insulating protective material which can maintain stable and excellent performances with no elution of ionic substances (referred to as "ionic impurity" hereinafter) present therein by capturing and fixing the ionic impurity by adding a specific hydrous oxide. Insulating protective materials used for protection of elements or contacts of electronic elements utilizing various functions such as semiconducting functions, dielectric functions, magnetic functions, insulating functions, coloring and decoloring function (e.g., diode, transistor, condenser, liquid crystal, thermistor, IC, LSI, etc) and electronic devices having these elements or indicator tubes are called sealers, casting materials, potting materials, interlaminer maintaining materials, junction coating materials, passivation materials, dipping materials, sealing materials, roller coating materials, drip coating materials and the like depending on their application purposes, devices, positions, means, etc. As components of these insulating protective materials (referred to as "protective material" hereinafter) there are known such fusion bonding materials as ceramic materials such as low-melting glasses and high-molecular weight materials such as epoxy resin, epoxysilicone resin, silicone resin, phenolic resin. In general, high-molecular weight materials are often used because of their good moldability, their mass-producibility, and because they are inexpensive. These are seldom used alone and are ordinarily used together with fillers. Typically useful inorganic fillers include lead titanate, fused silica, β-eucryptite, titanium oxide, glass fibers, glass beads and the like. Properties required for these protective materials are low-temperature and short-time fusibility and hardenability, low expansion or negative expansion against temperature rise, formation of strong sealing power and high insulation property. The insulation property is especially important. It has been said that various inhibition factors such as migration of ionic impurity in protective materials, moisture absorption of protective materials, charge density at the solid surface of protective materials, etc. are related in a complex manner to the insulation property resulting in bad effects thereon. Furthermore, halogen ions are considered to cause corrosion of electronic elements such as IC elements or lead wires. Many countermeasures for removing these effects have been proposed. Generally, the above effects on protective materials as final products are prevented by selection of raw materials and prevention of contamination in purification and production processes. Particularly, effects of alkali metal ions (Li + , Na + K + , etc) and halogen ions (F - , Cl - , Br - , etc) which are ionic impurities cannot be disregarded. Presence of these ions even in an amount of a few ppm is considered to cause reduction of insulation. These ionic impurities are desirably completely eliminated in the process of production of protective materials, but practically it is very severe burden from processing and economic viewpoints to eliminate even the slight amount of the ionic impurities. The alkali metal ions and halogen ions come from the impurities in inorganic fillers which are a constitutional component of the protective materials such as fused silica, titanium oxide, β-eucryptite, glass fibers, glass beads, etc., but some come from raw materials for organic high molecular weight materials which are another component of the protective materials. For example, an epoxy resin is most commonly used as a component of protective materials. It is synthesized from epichlororhydrin ##STR1## According to this synthesis reaction dehydrochlorination is carried out with a catalyst such as an alkali hydroxide and sodium chloride is produced as a reaction product. The synthesis is performed using excess epichlorohydrin and so there remains unreacted epichlorohydrin in the epoxy resin provided as a component of protective materials. In this case the halogen present as a functional group does not have effect on insulation in chemically bonded state, but the remaining unreacted epichlorohydrin often decomposes under some condition and behaves as an ionic impurity. Furthermore, sulfur-containing organic high molecular weight compounds such as polyether sulfone ##STR2## polyphenylene sulfide ##STR3## polysulfone sulfide ##STR4## etc. are expected to displace epoxy resins. However, as with epoxy resins, production of these compounds requires organic halogen compounds, e.g., 1,4-dichlorobenzene ##STR5## and dichlorodiphenyl sulfone ##STR6## as starting materials and the synthesis reactions all comprise sodium chloride elimination reaction. In these cases, the produced polyether sulfone, polyphenylene sulfide and polysulfone sulfide, usually contain unreacted halogen compounds, which are decomposed by heat, moisture and the like to produce halogens. For this reason these compounds, though they are effective as a components of protective materials, have not yet been practically used. On the other hand, some of the fillers which constitute the protective material contain an alkali metal ion as a principal component and such component is known to play a part of the performance of the protective material. For example, β-eucryptite (LiO 2 ·Al 2 O 3 ·nSiO 2 ) has a negative expansion property against increasing temperature. Owing to this property attempts have been made to utilize this substance as a filler for protective materials. However, β-eucryptite is also a conductor of lithium ion and lithium ions move in an electric field. From the viewpoint of insulation property of protective materials β-eucryptite must be regarded as an ionic impurity which cause undesirable results. Since ions present in protective materials move with electrical charge to give electrical conductivity, it is necessary for improving insulation to provide conditions to prevent the migration of ions. SUMMARY OF THE INVENTION This invention provides an excellent insulating protective material in which ions remaining in the protective material as impurities or ions in the principal component such as lithium ion in βeucryptite are all captured and fixed as ionic impurities without allowing migration. The above object has been achieved by an insulating protective material which contains at least one hydrous oxide of a metal which has ion exchange properties. It is disclosed in Japanese Patent Unexamined Publications (Kokai) No. 176237/83 and No. 174435/83 to add to a sealing material a substance having ion exchange property, e.g., ion exchange resin, zeolite, zirconium phosphate, etc. However, it is not known that a hydrous oxide of a metal which has ion exchange properties captures and fixes simultaneously and efficiently alkali metal ions such as sodium, potassium, lithium, etc. and halogen ions such as chlorine, etc. This remarkable effect has been found by the inventors. DETAILED DESCRIPTION OF THE INVENTION The hydrous oxides of metals which have ion exchange properties used in the insulating protective materials according to this invention include those which have cation exchange properties, especially for alkali metal ions, those which have anion exchange properties, especially for halogen ions and those which have both anion and cation exchange properties. Typical examples of those which have alkali metal ion exchange properties are polyvalent metal hydrous oxides such as antimonic acid, tantalic acid, niobic acid, etc. and salts thereof. These hydrous oxides all have --O - H + bond which exhibits ion exchange property and in which H + is exchangeable with an alkali metal ion. As typical examples of hydrous oxides having halogen ion exchange properties, mention may be made of those which have -OH bond as above mentioned such as hydrotalcite (Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O), hydrous iron oxide, hydrous zirconium oxide, hydrous titanium oxide, hydrous tin oxide, hydrous manganese oxide, hydrous bismuth oxide, etc. These are preferably used in combination with said oxides having alkali metal ion exchange properties. Typical examples of those which have both the anion and cation exchange properties are composite salts such as manganese antimonate, bismuth antimonate, tin antimonate, titanium antimonate, zirconium antimonate, etc. These may be used properly depending on uses. Of these hydrous oxides of various metals, especially useful are antimonic acid and salts thereof, hydrous bismuth oxide, hydrous manganese oxide, hydrous tin oxide, hydrous titanium oxide, hydrous zirconium oxide, etc. The method of using these hydrous oxides depends on kind and amount of ions to be captured in protective materials and balance of other properties as protective materials. The amount of the hydrous oxides added is preferably 40% by weight or less, especially 1.5-25% by weight per total weight of the protective material. When the amount is too small, the ionic impurities cannot be captured and fixed and too large amount adversely influences the inherent sealing effect of the protective material and moreover is economically unsound. The ionic form of the hydrous oxides having cation exchange properties is preferably the H form, but it may be a salt form which has other metal ion partially replaced. This is because inorganic fillers are considered to contain alkaline ionic impurities and unnecessary metal ion impurities should not be increased. When the hydrous oxide having cation exchange properties is in monobasic acid form MO - H + , this oxide reacts with an alkaline ionic impurity A + OH - as follows: MO.sup.- H.sup.+ +A.sup.+ OH→MO.sup.- A.sup.+ +H.sub.2 O Water is liberated in this reaction. This water is removed from the system by heat treatment when IC packages, electronics elements, etc. are insulation protected with the protective material, resulting in improvement of insulation properties. The compounds having anion exchange properties have an ion form which is preferably the OH form, but this may be partially replaced with other anion. When the hydrous oxide having anion exchange properties has a monoacidic base form of N + OH - , this reacts with anionic impurity H + X - (example of halogenous acids) as shown below to liberate water. N.sup.+ OH.sup.- +H.sup.+ X.sup.- →N.sup.+ X.sup.- +H.sub.2 O Similarly, joint use of said cation exchange compound MO - H + and said anion exchange compound N + OH - for neutral form impurity A + X - results in water as follows: MO.sup.- H.sup.+ +A.sup.+ →MO.sup.- A.sup.+ +H.sup.+ N.sup.+ OH.sup.- +X.sup.- →N.sup.+ X.sup.- +OH.sup.- H.sup.+ +OH.sup.- →H.sub.2 O The product water is removed from the system by heat treatment and so does not damage the insulation properties. In this invention there may be used hydrous oxides of metals which have cation exchange properties, those having anion exchange properties and those having both the anion and cation exchange properties. However, considering the efficiency of capturing and fixing halogen ions and alkali ions, it is preferred to use those having both the anion and cation exchange properties or to use mixtures of those having cation exchange properties with those having anion exchange properties. The hydrous oxides of metals which have only cation exchange properties or only anion exchange properties are not completely satisfactory for capturing and fixing impurity ions. Even if pH of the protective material is changed in an attempt to improve the efficiency, halogen ions may be captured, but alkali ions may not be captured or conversely, alkali ions may be captured, but halogen ions may not be captured. These problems can be removed by joint use of both the cation exchange oxides and anion exchange oxides. According to this invention the hydrous oxide may be used as a uniform mixture in a protective composition or used so that it covers the surface of an inorganic filler. As aforementioned, known materials such as low-melting glass, epoxy resin, phenolic resin and silicone resin for fusion bonding and fused silica, β-eucryptite glass fibers and glass beads are selected as fillers and used in combination with the others components of the protective materials of this invention. It is one of the superior effects of this invention that is possible to use as additional components in the insulating protective materials of this invention, sulfur-containing organic high molecular weight compounds such as polyether sulfone, polyphenylene sulfide, polysulfone sulfide, etc. which are produced using organic compounds having halogen atom. It has heretofor been difficult to use these materials in this field. The following non-limiting examples and comparative examples illustrate this invention. EXAMPLE 1 AND COMPARATIVE EXAMPLE 1 Antimony pentachloride and tin tetrachloride in a molar ratio of 3:1 were dissolved in 6N aqueous HCl solution. The resultant solution was diluted with water to an acid concentration of 2N to hydrolyze the antimony pentachloride and antimony tetrachloride. The mixture was then digested at 60° C. for 6 hours. Then, the product was filtered out with a filter of 0.4μ to obtain a mixture containing antimonic acid and stannic acid (referred to as "tin antimonate (molar ratio of Sb:Sn is 3:1)" hereinafter). The resultant tin antimonate (3:1) was washed with water and then calcined at 200° C. to remove water and hydrochloric acid. 0.5 g of thus prepared tin antimonate (3:1), 4.0 g of β-eucryptite, 2.1 g of O-cresol novolak type epoxy resin and 0.1 g of an imidazole curing agent were well mixed and the mixture was hardened and molded into a plate of 55 mm long×55 mm wide×2 mm thick in a press under the conditions of 175° C., 100 kg/cm 2 and 30 minutes. Then, square plates of 1 cm×1 cm were cut out from said hardened plate by a knife and employed as sample plates. A number of these samples weighing totally about 2 g were placed in a pyrex vessel, into which 20 ml of water was poured. This pyrex vessel was placed in an autoclave and heated at 100°-120° C. and a gauge pressure of 1 kg/cm 2 to elute alkali metal ions. After cooling, the vessel was taken out and sodium ion and chlorine ion eluted into water were analyzed (Example 1). Similarly, a blank test was conducted in the absence of tin antimonate (3:1) (Comparative Example 1). The results are shown in Table 1. As is recognized therefrom elution of the ions in the presence of tin antimonate (3:1) was less than 1/10 of elution in the absence of tin antimonate (3:1) and the ions were fixed in the hardened plate in the former case. TABLE 1______________________________________ Tin antimonate (3:1) Eluted Na Eluted Cl______________________________________Example 1 Present 9.0 ppm 3 ppmComparative Absent 122 ppm 60 ppmExample 1 (Blank)______________________________________ EXAMPLES 2 AND 3 In accordance with the manner of preparation of tin antimonate (3:1) in Example 1, antimony pentachloride and bismuth nitrate in the molar ratio of 1:1 and antimony pentachloride and metallic manganese in the molar ratio of 1:1 were hydrolyzed under the acid concentration of Example 1 to obtain a mixed acid of antimonic acid and bismuthic acid (referred to as "bismuth antimonate (molar ratio of Sb:Bi is 1:1)" hereinafter) and a mixture containing antimonic acid and manganic acid (referred to as "manganese antimonate (molar ratio of Sb:Mn is 1:1)" hereinafter). These were washed with water and calcined as in Example 1. In the same manner as in Example 1 each of 0.5 g of thus obtained hydrous oxides was mixed with the β-eucryptite, the epoxy resin and the curing agent to obtain a hardened plate, respectively. These were subjected to the same test as in Example 1 to examine elution of ions (Examples 2 and 3). The results are shown in Table 2. Elution of ions was markedly prevented as compared with the blank test of Comparative Example 1 and the ions were fixed in the hardened plates. TABLE 2______________________________________ Hydrous oxide Eluted Na Eluted Cl______________________________________Example 2 Bismuth 5 ppm 1 ppm antimonate (1:1)Example 3 Manganese <1 ppm 4 ppm antimonate (1:1)______________________________________ COMPARATIVE EXAMPLE 2 Zirconium oxychloride and concentrated phosphoric acid were allowed to react with heating in the presence of excess phosphoric acid followed by filtration and washing with water to produce zirconium phospate. This zirconium phosphate was half-neutralized with NaOH to obtain a neutral form of zirconium phosphate. This compound was thoroughly washed with water and then calcined at 200° C. The resultant zirconium phosphate of neutral form was indicated by ZrNaH(PO 4 ) 2 . In the same manner as in Example 1, a hardened plate was prepared using 0.5 g of ZrNaH(PO 4 ) 2 and subjected to the hot water elution test. Analysis was effected for sodium, potassium and chlorine ions. The results are shown in Table 3 in comparison with the results on the blank test piece of Comparative Example 1. As is clear therefrom the zirconium phosphate had some effects on sodium and potassium ions, but utterly no effects on chlorine ion. TABLE 3______________________________________Additives Eluted Na Eluted K Eluted Cl______________________________________Compar- ZrNaH(PO.sub.4).sub.2 23 ppm <1 ppm 58 ppmativeExample 2Compar- -- (Blank) 122 ppm 7 ppm 60 ppmativeExample 1______________________________________ COMPARATIVE EXAMPLE 3 In the same manner as preparation of zirconium phosphate in Comparative Example 2, cerium phosphate, tin phosphate and titanium phosphate all in neutral form were prepared using cerium sulfate, tin tetrachloride and titanium tetrachloride. Using these compounds as hydrous oxides, hardened plates with the same constitution as those of Example 1 were made and subjected to the test for elution of alkali metal ions to obtain nearly the same results as in Comparative Example 2. EXAMPLE 4 Potassium pyroantimonate and tin tetrachloride were mixed so that molar ratio of antimony and tin was 1:2 and sufficient hydrochloric acid was added so that acid the concentration of the aqueous solution was 2N. In accordance with the procedure of Example 1 there was obtained a composite acid tin antimonate (1:1.8) containing antimonic acid and stannic acid in a molar ratio of 1:1.8. 0.5 g of thus obtained tin antimonate (1:1.8) was homogeneously mixed with 4.0 g of β-eucryptite, 2.1 g of a novolak type epoxy resin and 0.5 g of an imidazole curing agent and the mixture was hardened under heat by the method of Example 1. The resulting plates were subjected to the hot water elution test. The results obtained on sodium, lithium and chlorine ions are shown in Table 4 together with the results of the blank test (Comparative Example 1). It is recognized that they have effect on Li + ion, too. TABLE 4______________________________________ Hydrous oxide Eluted Na Eluted Li Eluted Cl______________________________________Example 4 Tin 7.1 ppm 5 ppm 6 ppm antimonate (1:1.8)Comparative -- 122 ppm 80 ppm 60 ppmExample 1 (Blank)______________________________________ EXAMPLES 5-6 AND COMPARATIVE EXAMPLE 4 Titanium antimonate (1:1) and zirconium antimonate (1:1) were prepared from antimony pentachloride and titanium tetrachloride in a molar ratio of 1:1 and from antimony pentachloride and zirconium oxychloride in a molar ratio of 1:1, respectively, in the same manner as in Example 1. 0.5 g of each thus obtained hydrous oxides, 4.5 g of fused silica, 2.1 g of O-cresol novolak type epoxy resin and 0.1 g of imidazole type curing agent were homogeneously mixed and the mixtures were hardened in the manner of Example 1 (Examples 5-6). These products were subjected to the same hot water elution test as of Example 1 and the results are shown in Table 5 in comparison with the results of the blank test (Comparative Example 4). TABLE 5______________________________________ Hydrous Oxide Eluted Na Eluted Cl______________________________________Example 5 Titanium <1 ppm <1 ppm antimonate (1:1)Example 6 Zirconium <1 ppm 2 ppm antimonate (1:1)Comparative -- (Blank) 10 ppm 18 ppmExample 4______________________________________ EXAMPLES 7-8 AND COMPARATIVE EXAMPLE 5 Antimony trioxide and bismuth trioxide in an atomic ratio of antimony and bismuth of 3:1 were dissolved in aqua regia of 4:1 (HCl:HNO 3 ) followed by hydrolysis so that the acid concentration was 2N-3N. The mixture was digested under heat at 75° C. for 8 hours. Thereafter, the product was filtered with a precision filter of 0.4μ and thoroughly washed with water to obtain acid mixture containing antimonic acid and bismuthic acid (which was called "bismuth antimonate (molar ratio of Sb:Bi is 3:1)" hereinafter). The bismuth antimonate (3:1) was calcined at 230° C. to remove the remaining water and acid. 0.4 g of thus obtained bismuth antimonate (3:1) was well mixed with 4.0 g of β-eucryptite, 1.9 g of O-cresol novolak type resin and 0.6 g of an imidazole type curing agent in a ball mill. The mixture was hardened and molded in a mold press into a 60 mm×60 mm×2 mm plate under the conditions of 175° C., 100 kg/cm 2 and 45 minutes. In the manner of Example 1 sodium, potassium and chlorine ions eluted from the hardened plate into water were analyzed (Example 7). Similarly, a composite acid of antimonic acid and manganic acid in an atomic ratio of metals of 3:2 (which was called "manganese antimonate (molar ratio of Sn:Mn is 3:2)" hereinafter) was prepared and subjected to the similar test (Example 8). Separately, a blank test was conducted in the absence of the hydrous oxide (Comparative Example 5). The results of Examples 7-8 and Comparative Example 5 are shown in Table 6. It is clear therefrom that in Examples 7-8 sodium, potassium and chlorine ions were captured and fixed in the hardened plate and prevented from election therefrom as compared with in the blank test of Comparative Example 5. TABLE 6______________________________________ Hydrous oxide Eluted Na Eluted K Eluted Cl______________________________________Example 7 Bismuth 3.5 ppm <1 ppm <1 ppm antimonate (3:1)Example 8 Manganese <1 ppm <1 ppm 4 ppm antimonate (3:2)Comparative -- (Blank) 130 ppm 9 ppm 65 ppmExample 5______________________________________ EXAMPLE 9 AND COMPARATIVE EXAMPLE 6 Potassium pyroantimonate and tin tetrachloride were mixed so that the molar ratio of antimony and tin became 1:2.5 and from the mixture was prepared a composite acid of antimonic acid and stannic acid in a molar ratio of 1:2.3, namely, tin antimonate (1:2.3). In accordance with the manner of Example 4 except that the antimonic acid and stannic acid molar ratio was 1:2.3, a hot water elution test was effected using said tin antimonate (1:2.3). The results are shown in Table 7 together with the results of the blank test for sodium and lithium ions (Comparative Example 6), from which it is recognized that the hydrous oxide used displayed effects also for Li + ion. TABLE 7______________________________________ Hydrous oxide Eluted Na Eluted Li______________________________________Example 9 Tin antimonate 11 ppm 3 ppm (1:2.3)Comparative -- (Blank) 130 ppm 65 ppmExample 6______________________________________ EXAMPLES 10-11 AND COMPARATIVE EXAMPLE 7 In the same manner as in Example 7 titanium antimonate (3:2) and zirconium antimonate (3:2) were prepared from antimony pentachloride and titanium tetrachloride in a molar ratio of 3:2 and antimony pentachloride and zirconium oxychloride in a molar ratio of 3:2, respectively. In accordance with the procedure of Example 5 utilizing the same amounts of fused silica, o-cresol novolak type epoxy resins and imidazole type curing agent, the hot water elution test was carried out for said hydrous oxides. The results are shown in Table 8 in comparison with the results of blank test (Comparative Example 6). TABLE 8______________________________________ Hydrous oxide Eluted Na Eluted Cl______________________________________Example 10 Titanium <1 ppm <1 ppm antimonate (3:2)Example 11 Zirconium <1 ppm <1 ppm antimonate (3:2)Comparative -- (Blank) 10 ppm 18 ppmExample 7______________________________________ EXAMPLE 12 AND COMPARATIVE EXAMPLE 8 0.6 g of tin antimonate (2:1) obtained in accordance with the procedure of Example 7, 5.4 g of fused silica and 4.0 g of polyphenylene sulfide were well mixed by a powder mixer and placed in a mold and calcined at 350° C. to mold into a plate of 2 mm thick. In the same manner as in Example 7 sodium ion eluted from this molded product into water was analyzed (Example 12). Separately, a blank test was effected in the absence of the tin antimonate (2:1) (Comparative Example 8). As shown in Table 9, elution of sodium ion in the presence of tin antimonate (2:1) was less than 1/10 of that of sodium ion in the absence of tin antimonate (2:1). Thus, it is clear that sodium ion was captured and fixed in the hardened plate. TABLE 9______________________________________ Tin antimonate (2:1) Eluted Na______________________________________Example 12 Present 11 ppmComparative Absent (Blank) 145 ppmExample 8______________________________________ EXAMPLES 13-14 AND COMPARATIVE EXAMPLE 9 0.6 g of bismuth antimonate (3:1) obtained according to the method of Example 7, 5.4 g of fused silica and 5.0 g of polyether sulfone were well mixed by a powder mixer and calcined and molded at 350° C. in a mold to obtain a molded plate similar to that of Example 12. In the same manner as in Example 7 the plate was subjected to the hot water elution test to examine elution of sodium, potassium and chlorine ions into hot water (Example 13). The same test utilizing the same amounts of fused silica and polyether sulfone was conducted for manganese antimonate (3:2) obtained by the method of Example 7 (Example 14). Similarly, a blank test was carried out in the absence of bismuth antimonate (3:1) and manganese antimonate (3:2) in Examples 13 and 14 (Comparative Example 9). The results of Example 13, Example 14 and Comparative Example 9 are shown in Table 10. Sodium ion and potassium ion were captured and fixed in the hardened plate and elution of these ions was remarkably prevented as compared with in the blank test of Comparative Example 9. TABLE 10______________________________________ Eluted ions Hydrous oxide Na.sup.+ K.sup.+ Cl.sup.-______________________________________Example 13 Bismuth 5 ppm <1 ppm 3.5 ppm antimonate (3:1)Example 14 Manganese <1 ppm <1 ppm 70 ppm antimonate (3:2)Comparative -- (Blank) 70 ppm 5.0 ppm 110 ppmExample 9______________________________________ EXAMPLE 15 AND COMPARATIVE EXAMPLE 10 10 g of bismuth nitrate pentahydrate and 8 g of mannitol were mixed for 15 minutes. The mixture was dissolved in 50 g of water. The solution was poured into 50 g of 20% aqueous sodium hydroxide solution and the total amount was made 550 ml with water. Thereafter, pH was made 10 by addition of 4N sulfuric acid. The resultant precipitate was left to stand to room temperature for 24 hours, digested, filtered out and then washed with water until no sodium ion was detected. Thereafter, the product was calcined at 350° C. for 1 hour to obtain hydrous bismuth oxide. 0.3 g of thus obtained hydrous bismuth oxide, 0.3 g of manganese antimonate obtained in Example 14, 4 g of polyphenylene sulfide and 4 g of fused silica were mixed by a powder mixer. The mixture was molded in the same manner as in Example 12. The molded product was subjected to the same hot water elution test as in Example 12 to analyze sodium ion and chlorine ion (Example 15). Similarly, a blank test was effected in the absence of the hydrous bismuth oxide and the manganese antimonate (Comparative Example 10). The results are shown in Table 11. TABLE 11______________________________________ Eluted ion Hydrous oxide Na Cl______________________________________Example 15 Hydrous bismuth 2.1 ppm 2.6 ppm oxide + manganese antimonateComparative -- (Blank) 135 ppm 171 ppmExample 10______________________________________
This invention provides an insulating protective material effective for protection of electronic and electric devices such as electronics elements. This insulating protective material contains at least one hydrous oxide of a metal which has ion exchange properties together with a fusion bonding component such as low-melting glass, epoxy resin, phenolic resin, silicone resin, etc. and a filler such as fused silica, β-eucryptite, glass fiber, glass beads, etc. Said specific hydrous oxide can be used together with a sulfur-containing organic high molecular weight compound. The hydrous oxides used in protective materials as a sealing material for electronic and electric devices can capture an ionic impurity eluted from the components of the protective material and fix it therein thereby to provide stable electronic materials excellent in performance.
Briefly outline the background technology and the problem the invention aims to solve.
[ "BACKGROUND OF THE INVENTION This invention relates to an insulating protective material effective for protecting electronic and electrical components such as electronic elements and the like.", "More particularly it relates to protective material used for protecting elements, contacts, etc.", "of IC packages and electronic devices including the IC packages used as electronic materials or electronic and electrical components such as electronic elements, e.g., indicator tubes.", "According to this invention there is provided an insulating protective material which can maintain stable and excellent performances with no elution of ionic substances (referred to as "ionic impurity"", "hereinafter) present therein by capturing and fixing the ionic impurity by adding a specific hydrous oxide.", "Insulating protective materials used for protection of elements or contacts of electronic elements utilizing various functions such as semiconducting functions, dielectric functions, magnetic functions, insulating functions, coloring and decoloring function (e.g., diode, transistor, condenser, liquid crystal, thermistor, IC, LSI, etc) and electronic devices having these elements or indicator tubes are called sealers, casting materials, potting materials, interlaminer maintaining materials, junction coating materials, passivation materials, dipping materials, sealing materials, roller coating materials, drip coating materials and the like depending on their application purposes, devices, positions, means, etc.", "As components of these insulating protective materials (referred to as "protective material"", "hereinafter) there are known such fusion bonding materials as ceramic materials such as low-melting glasses and high-molecular weight materials such as epoxy resin, epoxysilicone resin, silicone resin, phenolic resin.", "In general, high-molecular weight materials are often used because of their good moldability, their mass-producibility, and because they are inexpensive.", "These are seldom used alone and are ordinarily used together with fillers.", "Typically useful inorganic fillers include lead titanate, fused silica, β-eucryptite, titanium oxide, glass fibers, glass beads and the like.", "Properties required for these protective materials are low-temperature and short-time fusibility and hardenability, low expansion or negative expansion against temperature rise, formation of strong sealing power and high insulation property.", "The insulation property is especially important.", "It has been said that various inhibition factors such as migration of ionic impurity in protective materials, moisture absorption of protective materials, charge density at the solid surface of protective materials, etc.", "are related in a complex manner to the insulation property resulting in bad effects thereon.", "Furthermore, halogen ions are considered to cause corrosion of electronic elements such as IC elements or lead wires.", "Many countermeasures for removing these effects have been proposed.", "Generally, the above effects on protective materials as final products are prevented by selection of raw materials and prevention of contamination in purification and production processes.", "Particularly, effects of alkali metal ions (Li + , Na + K + , etc) and halogen ions (F - , Cl - , Br - , etc) which are ionic impurities cannot be disregarded.", "Presence of these ions even in an amount of a few ppm is considered to cause reduction of insulation.", "These ionic impurities are desirably completely eliminated in the process of production of protective materials, but practically it is very severe burden from processing and economic viewpoints to eliminate even the slight amount of the ionic impurities.", "The alkali metal ions and halogen ions come from the impurities in inorganic fillers which are a constitutional component of the protective materials such as fused silica, titanium oxide, β-eucryptite, glass fibers, glass beads, etc.", ", but some come from raw materials for organic high molecular weight materials which are another component of the protective materials.", "For example, an epoxy resin is most commonly used as a component of protective materials.", "It is synthesized from epichlororhydrin ##STR1## According to this synthesis reaction dehydrochlorination is carried out with a catalyst such as an alkali hydroxide and sodium chloride is produced as a reaction product.", "The synthesis is performed using excess epichlorohydrin and so there remains unreacted epichlorohydrin in the epoxy resin provided as a component of protective materials.", "In this case the halogen present as a functional group does not have effect on insulation in chemically bonded state, but the remaining unreacted epichlorohydrin often decomposes under some condition and behaves as an ionic impurity.", "Furthermore, sulfur-containing organic high molecular weight compounds such as polyether sulfone ##STR2## polyphenylene sulfide ##STR3## polysulfone sulfide ##STR4## etc.", "are expected to displace epoxy resins.", "However, as with epoxy resins, production of these compounds requires organic halogen compounds, e.g., 1,4-dichlorobenzene ##STR5## and dichlorodiphenyl sulfone ##STR6## as starting materials and the synthesis reactions all comprise sodium chloride elimination reaction.", "In these cases, the produced polyether sulfone, polyphenylene sulfide and polysulfone sulfide, usually contain unreacted halogen compounds, which are decomposed by heat, moisture and the like to produce halogens.", "For this reason these compounds, though they are effective as a components of protective materials, have not yet been practically used.", "On the other hand, some of the fillers which constitute the protective material contain an alkali metal ion as a principal component and such component is known to play a part of the performance of the protective material.", "For example, β-eucryptite (LiO 2 ·Al 2 O 3 ·nSiO 2 ) has a negative expansion property against increasing temperature.", "Owing to this property attempts have been made to utilize this substance as a filler for protective materials.", "However, β-eucryptite is also a conductor of lithium ion and lithium ions move in an electric field.", "From the viewpoint of insulation property of protective materials β-eucryptite must be regarded as an ionic impurity which cause undesirable results.", "Since ions present in protective materials move with electrical charge to give electrical conductivity, it is necessary for improving insulation to provide conditions to prevent the migration of ions.", "SUMMARY OF THE INVENTION This invention provides an excellent insulating protective material in which ions remaining in the protective material as impurities or ions in the principal component such as lithium ion in βeucryptite are all captured and fixed as ionic impurities without allowing migration.", "The above object has been achieved by an insulating protective material which contains at least one hydrous oxide of a metal which has ion exchange properties.", "It is disclosed in Japanese Patent Unexamined Publications (Kokai) No. 176237/83 and No. 174435/83 to add to a sealing material a substance having ion exchange property, e.g., ion exchange resin, zeolite, zirconium phosphate, etc.", "However, it is not known that a hydrous oxide of a metal which has ion exchange properties captures and fixes simultaneously and efficiently alkali metal ions such as sodium, potassium, lithium, etc.", "and halogen ions such as chlorine, etc.", "This remarkable effect has been found by the inventors.", "DETAILED DESCRIPTION OF THE INVENTION The hydrous oxides of metals which have ion exchange properties used in the insulating protective materials according to this invention include those which have cation exchange properties, especially for alkali metal ions, those which have anion exchange properties, especially for halogen ions and those which have both anion and cation exchange properties.", "Typical examples of those which have alkali metal ion exchange properties are polyvalent metal hydrous oxides such as antimonic acid, tantalic acid, niobic acid, etc.", "and salts thereof.", "These hydrous oxides all have --O - H + bond which exhibits ion exchange property and in which H + is exchangeable with an alkali metal ion.", "As typical examples of hydrous oxides having halogen ion exchange properties, mention may be made of those which have -OH bond as above mentioned such as hydrotalcite (Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O), hydrous iron oxide, hydrous zirconium oxide, hydrous titanium oxide, hydrous tin oxide, hydrous manganese oxide, hydrous bismuth oxide, etc.", "These are preferably used in combination with said oxides having alkali metal ion exchange properties.", "Typical examples of those which have both the anion and cation exchange properties are composite salts such as manganese antimonate, bismuth antimonate, tin antimonate, titanium antimonate, zirconium antimonate, etc.", "These may be used properly depending on uses.", "Of these hydrous oxides of various metals, especially useful are antimonic acid and salts thereof, hydrous bismuth oxide, hydrous manganese oxide, hydrous tin oxide, hydrous titanium oxide, hydrous zirconium oxide, etc.", "The method of using these hydrous oxides depends on kind and amount of ions to be captured in protective materials and balance of other properties as protective materials.", "The amount of the hydrous oxides added is preferably 40% by weight or less, especially 1.5-25% by weight per total weight of the protective material.", "When the amount is too small, the ionic impurities cannot be captured and fixed and too large amount adversely influences the inherent sealing effect of the protective material and moreover is economically unsound.", "The ionic form of the hydrous oxides having cation exchange properties is preferably the H form, but it may be a salt form which has other metal ion partially replaced.", "This is because inorganic fillers are considered to contain alkaline ionic impurities and unnecessary metal ion impurities should not be increased.", "When the hydrous oxide having cation exchange properties is in monobasic acid form MO - H + , this oxide reacts with an alkaline ionic impurity A + OH - as follows: MO.", "sup.", "- H.sup.", "+ +A.", "sup.", "+ OH→MO.", "sup.", "- A.sup.", "+ +H.", "sub[.", "].2 O Water is liberated in this reaction.", "This water is removed from the system by heat treatment when IC packages, electronics elements, etc.", "are insulation protected with the protective material, resulting in improvement of insulation properties.", "The compounds having anion exchange properties have an ion form which is preferably the OH form, but this may be partially replaced with other anion.", "When the hydrous oxide having anion exchange properties has a monoacidic base form of N + OH - , this reacts with anionic impurity H + X - (example of halogenous acids) as shown below to liberate water.", "N.sup.", "+ OH.", "sup.", "- +H.", "sup.", "+ X.sup.", "- →N.", "sup.", "+ X.sup.", "- +H.", "sub[.", "].2 O Similarly, joint use of said cation exchange compound MO - H + and said anion exchange compound N + OH - for neutral form impurity A + X - results in water as follows: MO.", "sup.", "- H.sup.", "+ +A.", "sup.", "+ →MO.", "sup.", "- A.sup.", "+ +H.", "sup.", "+ N.sup.", "+ OH.", "sup.", "- +X.", "sup.", "- →N.", "sup.", "+ X.sup.", "- +OH.", "sup.", "- H.sup.", "+ +OH.", "sup.", "- →H.", "sub[.", "].2 O The product water is removed from the system by heat treatment and so does not damage the insulation properties.", "In this invention there may be used hydrous oxides of metals which have cation exchange properties, those having anion exchange properties and those having both the anion and cation exchange properties.", "However, considering the efficiency of capturing and fixing halogen ions and alkali ions, it is preferred to use those having both the anion and cation exchange properties or to use mixtures of those having cation exchange properties with those having anion exchange properties.", "The hydrous oxides of metals which have only cation exchange properties or only anion exchange properties are not completely satisfactory for capturing and fixing impurity ions.", "Even if pH of the protective material is changed in an attempt to improve the efficiency, halogen ions may be captured, but alkali ions may not be captured or conversely, alkali ions may be captured, but halogen ions may not be captured.", "These problems can be removed by joint use of both the cation exchange oxides and anion exchange oxides.", "According to this invention the hydrous oxide may be used as a uniform mixture in a protective composition or used so that it covers the surface of an inorganic filler.", "As aforementioned, known materials such as low-melting glass, epoxy resin, phenolic resin and silicone resin for fusion bonding and fused silica, β-eucryptite glass fibers and glass beads are selected as fillers and used in combination with the others components of the protective materials of this invention.", "It is one of the superior effects of this invention that is possible to use as additional components in the insulating protective materials of this invention, sulfur-containing organic high molecular weight compounds such as polyether sulfone, polyphenylene sulfide, polysulfone sulfide, etc.", "which are produced using organic compounds having halogen atom.", "It has heretofor been difficult to use these materials in this field.", "The following non-limiting examples and comparative examples illustrate this invention.", "EXAMPLE 1 AND COMPARATIVE EXAMPLE 1 Antimony pentachloride and tin tetrachloride in a molar ratio of 3:1 were dissolved in 6N aqueous HCl solution.", "The resultant solution was diluted with water to an acid concentration of 2N to hydrolyze the antimony pentachloride and antimony tetrachloride.", "The mixture was then digested at 60° C. for 6 hours.", "Then, the product was filtered out with a filter of 0.4μ to obtain a mixture containing antimonic acid and stannic acid (referred to as "tin antimonate (molar ratio of Sb:Sn is 3:1)"", "hereinafter).", "The resultant tin antimonate (3:1) was washed with water and then calcined at 200° C. to remove water and hydrochloric acid.", "0.5 g of thus prepared tin antimonate (3:1), 4.0 g of β-eucryptite, 2.1 g of O-cresol novolak type epoxy resin and 0.1 g of an imidazole curing agent were well mixed and the mixture was hardened and molded into a plate of 55 mm long×55 mm wide×2 mm thick in a press under the conditions of 175° C., 100 kg/cm 2 and 30 minutes.", "Then, square plates of 1 cm×1 cm were cut out from said hardened plate by a knife and employed as sample plates.", "A number of these samples weighing totally about 2 g were placed in a pyrex vessel, into which 20 ml of water was poured.", "This pyrex vessel was placed in an autoclave and heated at 100°-120° C. and a gauge pressure of 1 kg/cm 2 to elute alkali metal ions.", "After cooling, the vessel was taken out and sodium ion and chlorine ion eluted into water were analyzed (Example 1).", "Similarly, a blank test was conducted in the absence of tin antimonate (3:1) (Comparative Example 1).", "The results are shown in Table 1.", "As is recognized therefrom elution of the ions in the presence of tin antimonate (3:1) was less than 1/10 of elution in the absence of tin antimonate (3:1) and the ions were fixed in the hardened plate in the former case.", "TABLE 1______________________________________ Tin antimonate (3:1) Eluted Na Eluted Cl______________________________________Example 1 Present 9.0 ppm 3 ppmComparative Absent 122 ppm 60 ppmExample 1 (Blank)______________________________________ EXAMPLES 2 AND 3 In accordance with the manner of preparation of tin antimonate (3:1) in Example 1, antimony pentachloride and bismuth nitrate in the molar ratio of 1:1 and antimony pentachloride and metallic manganese in the molar ratio of 1:1 were hydrolyzed under the acid concentration of Example 1 to obtain a mixed acid of antimonic acid and bismuthic acid (referred to as "bismuth antimonate (molar ratio of Sb:Bi is 1:1)"", "hereinafter) and a mixture containing antimonic acid and manganic acid (referred to as "manganese antimonate (molar ratio of Sb:Mn is 1:1)"", "hereinafter).", "These were washed with water and calcined as in Example 1.", "In the same manner as in Example 1 each of 0.5 g of thus obtained hydrous oxides was mixed with the β-eucryptite, the epoxy resin and the curing agent to obtain a hardened plate, respectively.", "These were subjected to the same test as in Example 1 to examine elution of ions (Examples 2 and 3).", "The results are shown in Table 2.", "Elution of ions was markedly prevented as compared with the blank test of Comparative Example 1 and the ions were fixed in the hardened plates.", "TABLE 2______________________________________ Hydrous oxide Eluted Na Eluted Cl______________________________________Example 2 Bismuth 5 ppm 1 ppm antimonate (1:1)Example 3 Manganese <1 ppm 4 ppm antimonate (1:1)______________________________________ COMPARATIVE EXAMPLE 2 Zirconium oxychloride and concentrated phosphoric acid were allowed to react with heating in the presence of excess phosphoric acid followed by filtration and washing with water to produce zirconium phospate.", "This zirconium phosphate was half-neutralized with NaOH to obtain a neutral form of zirconium phosphate.", "This compound was thoroughly washed with water and then calcined at 200° C. The resultant zirconium phosphate of neutral form was indicated by ZrNaH(PO 4 ) 2 .", "In the same manner as in Example 1, a hardened plate was prepared using 0.5 g of ZrNaH(PO 4 ) 2 and subjected to the hot water elution test.", "Analysis was effected for sodium, potassium and chlorine ions.", "The results are shown in Table 3 in comparison with the results on the blank test piece of Comparative Example 1.", "As is clear therefrom the zirconium phosphate had some effects on sodium and potassium ions, but utterly no effects on chlorine ion.", "TABLE 3______________________________________Additives Eluted Na Eluted K Eluted Cl______________________________________Compar- ZrNaH(PO.", "sub[.", "].4).", "sub[.", "].2 23 ppm <1 ppm 58 ppmativeExample 2Compar- -- (Blank) 122 ppm 7 ppm 60 ppmativeExample 1______________________________________ COMPARATIVE EXAMPLE 3 In the same manner as preparation of zirconium phosphate in Comparative Example 2, cerium phosphate, tin phosphate and titanium phosphate all in neutral form were prepared using cerium sulfate, tin tetrachloride and titanium tetrachloride.", "Using these compounds as hydrous oxides, hardened plates with the same constitution as those of Example 1 were made and subjected to the test for elution of alkali metal ions to obtain nearly the same results as in Comparative Example 2.", "EXAMPLE 4 Potassium pyroantimonate and tin tetrachloride were mixed so that molar ratio of antimony and tin was 1:2 and sufficient hydrochloric acid was added so that acid the concentration of the aqueous solution was 2N.", "In accordance with the procedure of Example 1 there was obtained a composite acid tin antimonate (1:1.8) containing antimonic acid and stannic acid in a molar ratio of 1:1.8.", "0.5 g of thus obtained tin antimonate (1:1.8) was homogeneously mixed with 4.0 g of β-eucryptite, 2.1 g of a novolak type epoxy resin and 0.5 g of an imidazole curing agent and the mixture was hardened under heat by the method of Example 1.", "The resulting plates were subjected to the hot water elution test.", "The results obtained on sodium, lithium and chlorine ions are shown in Table 4 together with the results of the blank test (Comparative Example 1).", "It is recognized that they have effect on Li + ion, too.", "TABLE 4______________________________________ Hydrous oxide Eluted Na Eluted Li Eluted Cl______________________________________Example 4 Tin 7.1 ppm 5 ppm 6 ppm antimonate (1:1.8)Comparative -- 122 ppm 80 ppm 60 ppmExample 1 (Blank)______________________________________ EXAMPLES 5-6 AND COMPARATIVE EXAMPLE 4 Titanium antimonate (1:1) and zirconium antimonate (1:1) were prepared from antimony pentachloride and titanium tetrachloride in a molar ratio of 1:1 and from antimony pentachloride and zirconium oxychloride in a molar ratio of 1:1, respectively, in the same manner as in Example 1.", "0.5 g of each thus obtained hydrous oxides, 4.5 g of fused silica, 2.1 g of O-cresol novolak type epoxy resin and 0.1 g of imidazole type curing agent were homogeneously mixed and the mixtures were hardened in the manner of Example 1 (Examples 5-6).", "These products were subjected to the same hot water elution test as of Example 1 and the results are shown in Table 5 in comparison with the results of the blank test (Comparative Example 4).", "TABLE 5______________________________________ Hydrous Oxide Eluted Na Eluted Cl______________________________________Example 5 Titanium <1 ppm <1 ppm antimonate (1:1)Example 6 Zirconium <1 ppm 2 ppm antimonate (1:1)Comparative -- (Blank) 10 ppm 18 ppmExample 4______________________________________ EXAMPLES 7-8 AND COMPARATIVE EXAMPLE 5 Antimony trioxide and bismuth trioxide in an atomic ratio of antimony and bismuth of 3:1 were dissolved in aqua regia of 4:1 (HCl:HNO 3 ) followed by hydrolysis so that the acid concentration was 2N-3N.", "The mixture was digested under heat at 75° C. for 8 hours.", "Thereafter, the product was filtered with a precision filter of 0.4μ and thoroughly washed with water to obtain acid mixture containing antimonic acid and bismuthic acid (which was called "bismuth antimonate (molar ratio of Sb:Bi is 3:1)"", "hereinafter).", "The bismuth antimonate (3:1) was calcined at 230° C. to remove the remaining water and acid.", "0.4 g of thus obtained bismuth antimonate (3:1) was well mixed with 4.0 g of β-eucryptite, 1.9 g of O-cresol novolak type resin and 0.6 g of an imidazole type curing agent in a ball mill.", "The mixture was hardened and molded in a mold press into a 60 mm×60 mm×2 mm plate under the conditions of 175° C., 100 kg/cm 2 and 45 minutes.", "In the manner of Example 1 sodium, potassium and chlorine ions eluted from the hardened plate into water were analyzed (Example 7).", "Similarly, a composite acid of antimonic acid and manganic acid in an atomic ratio of metals of 3:2 (which was called "manganese antimonate (molar ratio of Sn:Mn is 3:2)"", "hereinafter) was prepared and subjected to the similar test (Example 8).", "Separately, a blank test was conducted in the absence of the hydrous oxide (Comparative Example 5).", "The results of Examples 7-8 and Comparative Example 5 are shown in Table 6.", "It is clear therefrom that in Examples 7-8 sodium, potassium and chlorine ions were captured and fixed in the hardened plate and prevented from election therefrom as compared with in the blank test of Comparative Example 5.", "TABLE 6______________________________________ Hydrous oxide Eluted Na Eluted K Eluted Cl______________________________________Example 7 Bismuth 3.5 ppm <1 ppm <1 ppm antimonate (3:1)Example 8 Manganese <1 ppm <1 ppm 4 ppm antimonate (3:2)Comparative -- (Blank) 130 ppm 9 ppm 65 ppmExample 5______________________________________ EXAMPLE 9 AND COMPARATIVE EXAMPLE 6 Potassium pyroantimonate and tin tetrachloride were mixed so that the molar ratio of antimony and tin became 1:2.5 and from the mixture was prepared a composite acid of antimonic acid and stannic acid in a molar ratio of 1:2.3, namely, tin antimonate (1:2.3).", "In accordance with the manner of Example 4 except that the antimonic acid and stannic acid molar ratio was 1:2.3, a hot water elution test was effected using said tin antimonate (1:2.3).", "The results are shown in Table 7 together with the results of the blank test for sodium and lithium ions (Comparative Example 6), from which it is recognized that the hydrous oxide used displayed effects also for Li + ion.", "TABLE 7______________________________________ Hydrous oxide Eluted Na Eluted Li______________________________________Example 9 Tin antimonate 11 ppm 3 ppm (1:2.3)Comparative -- (Blank) 130 ppm 65 ppmExample 6______________________________________ EXAMPLES 10-11 AND COMPARATIVE EXAMPLE 7 In the same manner as in Example 7 titanium antimonate (3:2) and zirconium antimonate (3:2) were prepared from antimony pentachloride and titanium tetrachloride in a molar ratio of 3:2 and antimony pentachloride and zirconium oxychloride in a molar ratio of 3:2, respectively.", "In accordance with the procedure of Example 5 utilizing the same amounts of fused silica, o-cresol novolak type epoxy resins and imidazole type curing agent, the hot water elution test was carried out for said hydrous oxides.", "The results are shown in Table 8 in comparison with the results of blank test (Comparative Example 6).", "TABLE 8______________________________________ Hydrous oxide Eluted Na Eluted Cl______________________________________Example 10 Titanium <1 ppm <1 ppm antimonate (3:2)Example 11 Zirconium <1 ppm <1 ppm antimonate (3:2)Comparative -- (Blank) 10 ppm 18 ppmExample 7______________________________________ EXAMPLE 12 AND COMPARATIVE EXAMPLE 8 0.6 g of tin antimonate (2:1) obtained in accordance with the procedure of Example 7, 5.4 g of fused silica and 4.0 g of polyphenylene sulfide were well mixed by a powder mixer and placed in a mold and calcined at 350° C. to mold into a plate of 2 mm thick.", "In the same manner as in Example 7 sodium ion eluted from this molded product into water was analyzed (Example 12).", "Separately, a blank test was effected in the absence of the tin antimonate (2:1) (Comparative Example 8).", "As shown in Table 9, elution of sodium ion in the presence of tin antimonate (2:1) was less than 1/10 of that of sodium ion in the absence of tin antimonate (2:1).", "Thus, it is clear that sodium ion was captured and fixed in the hardened plate.", "TABLE 9______________________________________ Tin antimonate (2:1) Eluted Na______________________________________Example 12 Present 11 ppmComparative Absent (Blank) 145 ppmExample 8______________________________________ EXAMPLES 13-14 AND COMPARATIVE EXAMPLE 9 0.6 g of bismuth antimonate (3:1) obtained according to the method of Example 7, 5.4 g of fused silica and 5.0 g of polyether sulfone were well mixed by a powder mixer and calcined and molded at 350° C. in a mold to obtain a molded plate similar to that of Example 12.", "In the same manner as in Example 7 the plate was subjected to the hot water elution test to examine elution of sodium, potassium and chlorine ions into hot water (Example 13).", "The same test utilizing the same amounts of fused silica and polyether sulfone was conducted for manganese antimonate (3:2) obtained by the method of Example 7 (Example 14).", "Similarly, a blank test was carried out in the absence of bismuth antimonate (3:1) and manganese antimonate (3:2) in Examples 13 and 14 (Comparative Example 9).", "The results of Example 13, Example 14 and Comparative Example 9 are shown in Table 10.", "Sodium ion and potassium ion were captured and fixed in the hardened plate and elution of these ions was remarkably prevented as compared with in the blank test of Comparative Example 9.", "TABLE 10______________________________________ Eluted ions Hydrous oxide Na.", "sup.", "+ K.sup.", "+ Cl.", "sup.", "-______________________________________Example 13 Bismuth 5 ppm <1 ppm 3.5 ppm antimonate (3:1)Example 14 Manganese <1 ppm <1 ppm 70 ppm antimonate (3:2)Comparative -- (Blank) 70 ppm 5.0 ppm 110 ppmExample 9______________________________________ EXAMPLE 15 AND COMPARATIVE EXAMPLE 10 10 g of bismuth nitrate pentahydrate and 8 g of mannitol were mixed for 15 minutes.", "The mixture was dissolved in 50 g of water.", "The solution was poured into 50 g of 20% aqueous sodium hydroxide solution and the total amount was made 550 ml with water.", "Thereafter, pH was made 10 by addition of 4N sulfuric acid.", "The resultant precipitate was left to stand to room temperature for 24 hours, digested, filtered out and then washed with water until no sodium ion was detected.", "Thereafter, the product was calcined at 350° C. for 1 hour to obtain hydrous bismuth oxide.", "0.3 g of thus obtained hydrous bismuth oxide, 0.3 g of manganese antimonate obtained in Example 14, 4 g of polyphenylene sulfide and 4 g of fused silica were mixed by a powder mixer.", "The mixture was molded in the same manner as in Example 12.", "The molded product was subjected to the same hot water elution test as in Example 12 to analyze sodium ion and chlorine ion (Example 15).", "Similarly, a blank test was effected in the absence of the hydrous bismuth oxide and the manganese antimonate (Comparative Example 10).", "The results are shown in Table 11.", "TABLE 11______________________________________ Eluted ion Hydrous oxide Na Cl______________________________________Example 15 Hydrous bismuth 2.1 ppm 2.6 ppm oxide + manganese antimonateComparative -- (Blank) 135 ppm 171 ppmExample 10______________________________________" ]
TECHNICAL FIELD This invention relates to an apparatus for use in the field of cardiac electrophysiology. More specifically, an apparatus is disclosed for assessing ventricular tachyarrhythmias and determining defibrillation thresholds during implantable defibrillator procedures. BACKGROUND OF THE INVENTION In the United States, heart disease is a major health problem. Of the 1.5 million people per year who suffer a myocardial infarction, about 680,000 survive that have ischemia (dead heart tissue) which is the basis for cardiac arrhythmias. Approximately 400,000 people a year die from the most serious types of cardiac arrhythmias. Arrhythmias can be classified into three broad types. Bradycardia is an abnormally slow heart rhythm. This problem has been successfully treated for a number of years with implantable pacemakers which induce the heart to beat at a faster, normal rhythm. The remaining types of arrhythmias are more difficult to control. Tachycardia is a rapid cardiac rhythm generally defined as a heart rate greater than 100 beats per minute. There are normal physiologic tachycardias due to exertion or emotion as well as abnormal nonphysiologic tachycardias in which a high rate results in loss of blood pressure. Sustained ventricular tachycardia can result in severe loss of blood pressure, loss of consciousness and can deteriorate into ventricular fibrillation which is fatal if not quickly interrupted. Fibrillation, unlike tachycardia, is a disorganized cardiac rhythm wherein the heart quivers rather than beats. This quivering is a result of multiple waves of cardiac depolarization spreading and colliding throughout the ventricular tissue. Ventricular fibrillation results in a precipitous decrease in blood pressure followed quickly by brain damage and death. Arrhythmias are treated using either medication, surgery or implantation of a medical device. Drug therapy is employed initially in the majority of cases and involves the use of various medications to prevent an arrhythmia from starting or being sustained. The main advantage of drug therapy is that no surgical intervention is required. The major drawback to the exclusive use of therapy is the lack of backup therapy to terminate a potentially lethal arrhythmia should the drug eventually fail to prevent the arrhythmia from recurring. Additionally, in attempting to achieve adequate tachycardia prevention, drug related side effects often preclude using an adequate dose of medication. Surgery involves locating the cause of the arrhythmia and removing or isolating it from the healthy cardiac tissue. The advantage of surgical therapy is that the procedure is curative when successful. The disadvantage of surgical therapy is the morbidity and mortality associated with open heart surgery and the technical difficulty and high cost of the procedure. These factors have restricted the practice of antiarrhythmia surgery. In 1980, the first implantable defibrillator was implanted in a human patient. Implantable defibrillators sense fibrillation and automatically deliver a high energy pulse. Subsequent studies have indicated that these devices are effective in preventing sudden death from fibrillation. Presently, no single implantable device has been developed to control all three types of arrhythmias. The analysis of patients who have arrhythmias often requires invasive testing in an electrophysiology lab. This invasive testing is carried out in a variety of situations. For example, invasive testing is common during a selection process used to determine which patients might be candidates for implantable defibrillators. Invasive testing is also utilized in trying to assess and characterize tachycardia which is then treated with drugs. In any case, in the testing process, catheters are inserted into the heart and the patient's arrhythmia is provoked with programmed electrical stimulation. When the arrhythmia manifests itself, the physician attempts to terminate it with antitachycardia pacing. Antitachycardia pacing is described in the literature and consists of a series of low voltage pulses designed to reset the normal heartbeat. If pacing fails, the patient is either cardioverted with a substantially higher voltage shock or defibrillated with a very high voltage energy pulse. Low energy cardioversion utilizes pulses with energy levels far greater than pacing pulses but lower than high energy defibrillation pulses. With energies of less than 5 joules, this mode of therapy is based on the theory of interrupting the arrhythmia by stimulating the tissue, rendering it nonexcitable. Low energy cardioversion has been clinically demonstrated as effective. Its drawbacks include patient discomfort and the fact that improperly timed pulses can accelerate tachycardias and occasionally induce fibrillation. In contrast, high energy defibrillation uses pulses with energy levels tens of thousands of times greater than pacemaker pulses. High energy defibrillation is accomplished by stimulating a large portion of the ventricular tissues simultaneously and rendering it nonexcitable, thereby terminating the arrhythmia. If a patient is found suitable, an internal defibrillator can be implanted to control the arrhythmia. During the operation, the patient's defibrillation threshold must be determined. First, the patient is fibrillated using a programmable stimulator, then a special defibrillator is used to determine the energy required to defibrillate the patient. The invention described herein facilitates the assessment of arrhythmias and defibrillation thresholds resulting in improved patient care and substantially decreased patient risk. In the prior art, there existed both programmable stimulators and cardioversion/defibrillator devices. The programmable stimulator includes a means to pace the patient's heart with critically timed stimuli to provoke the cardiac arrhythmia. These devices are then used to terminate the arrhythmia using antitachycardia pacing. If the pacing accelerates the arrhythmia or fails to terminate it, then a standby defibrillator device must be set up and the patient cardioverted or defibrillated. Frequently, the patient is cardioverted or defibrillated externally. More recently, internal catheters have been provided to deliver the defibrillation shock. As noted above, an external cardioverter/defibrillator is used during implantable defibrillator procedures to assess the patient's cardioversion/defibrillation threshold. When the patient is fibrillated using a programmable stimulator, the unit must be disconnected before a test defibrillation pulse can be applied. Frequently, the test pulse fails to defibrillate the patient. Once the physician recognizes the failure to defibrillate, he must program a new, higher voltage rescue shock into the defibrillator. The unit must then recharge prior to delivery of the rescue shock. This procedure takes considerable time and there is ample opportunity for operator error. Any delay in defibrillating the patient is a serious health risk and improving the response time to the delivery of the rescue shock substantially reduces patient risk. Accordingly, it would be desirable to eliminate any unnecessary time between delivery of the test shock and rescue shock. In the above described procedures, it is also clear that in the electrophysiology lab, it is frequently necessary to use both a programmable stimulator and a cardioverter/defibrillator. Present day equipment requires the operator to switch leads and move back and forth between two pieces of equipment. During this procedure, care must be taken to prevent any of the high voltage charge delivered by the defibrillator from reaching the output leads of the programmable stimulator to avoid damaging the latter. Accordingly, it would be desirable to provide a single combination test unit wherein leads would not have to be changed and automatic protection of programmable stimulator would be provided. Another drawback of the defibrillation devices available in the prior art relates to the fact that little or no measurement and visual feedback is given to the surgeon regarding the defibrillation pulse. More specifically, the surgeon typically sets a pulse width and a voltage level for a test shock. If this test shock fails, the surgeon cannot be sure whether it was the result of shorted leads, an unexpectedly high resistance in the heart or whether the voltage was just too low to stop the defibrillation. There presently exists some low voltage pacing devices which have been designed to provide additional information to the surgeon regarding patient resistance and energy delivered. However, to date, no systems have been provided to calculate and display this information in a defibrillation setting. In a life-threatening situation, such as cardiac fibrillation, such information is extremely important and can aid the surgeon in assessing the type of rescue shock necessary to end the fibrillation. The energy delivered to the heart of a patient is generally measured in joules. The energy level of the shock is analogous to a dosage in therapy. In prior art devices, as in the subject invention, the surgeon sets the defibrillation shock by adjusting a voltage level and the pulse width. However, in the prior art devices, no information is given to the physician as to the energy which will be received by the patient if a shock with those set parameters were delivered. Therefore, it would be desirable to provide a device which displays the estimated energy based on the set voltage level and pulse width. Accordingly, it is an object of the subject invention to provide a new and improved apparatus for electrophysiology testing in patients suffering from severe ventricular arrhythmias. It is another object of the subject invention to provide a new and improved apparatus which advantageously combines a programmable stimulator and an internal cardioversion/defibrillation device. It is a further object of the subject invention to provide a combination stimulator/defibrillator apparatus with automatic circuit protection for the stimulator. It is a still another object of the subject invention to provide a new and improved defibrillator which includes a pair of capacitor banks permitting the simultaneous storage of both a test shock and a rescue shock. It is still a further object of the subject invention to provide a new and improved defibrillator apparatus which includes automatic recharge circuitry to reduce the time necessary to deliver a rescue shock during an emergency procedure. It is still another object of the subject invention to provide a new and improved apparatus which allows multiple, independent entries of data which are stored for later recall during testing procedures. It is still a further object of the subject invention to provide a new and improved defibrillator apparatus which will display measurement of resistance and energy delivered during a defibrillation shock. It is still a another object of the subject invention to provide a new and improved defibrillator apparatus which will display the energy which is estimated to be delivered if a shock of a given voltage and pulse width is to be delivered. SUMMARY OF THE INVENTION In accordance with these and many other objects, the subject invention provides a single device that can be used in electrophysiology labs during ventricular tachycardia procedures. The invention integrates an innovative two-channel defibrillator with a programmable stimulator in a manner that enhances response time to the patient and provides more information to the surgeon. A number of new features have been included which address unique problems encountered when treating severe arrhythmia. In use, an indwelling defibrillating catheter with pacing capabilities is inserted into the heart. In this manner, the arrhythmia can be induced by the subject apparatus and, if necessary, the patient can be defibrillated within seconds of the initiation of the arrhythmia. In accordance with the subject invention an automatic interrupt means is provided to protect the delicate circuits of the stimulator from the high voltage discharge delivered by the defibrillator without shunting current to the patient. Another advantage of the unique combination found in the subject invention is that the time necessary to initiate defibrillation is much shorter than is currently possible, resulting in decreased patient risk. To enhance the rapidity of defibrillation, the unit always remains charged to the programmed defibrillating voltages. Devices which exist in the prior art all have a charge button that must be pressed to initiate the charging of the storage capacitors. This feature was generally provided because the devices were subject to false triggering wherein the high voltage would be released inadvertently. In recent years, more reliable equipment has been developed which is not subject to false triggering. Nonetheless, the prior art devices still incorporate both a charge button (which is depressed to load the capacitor ) and a separate switch, which must be subsequently depressed, to the deliver the shock after the capacitor has been charged. In the emergency situation of a patient fibrillation event, the additional step of having to press a charge button can be delayed or overlooked. Even if the charge button is properly pressed, time will elapse before the capacitor bank is raised to the level of the desired shock. In the subject invention, the charge button is eliminated and an automatic circuit is provided to maintain the capacitor banks at the set voltage level. The defibrillation circuitry of the subject apparatus includes two independent channels. Each channel includes its own storage capacitors which can be independently programmed. Prior to a surgical procedure, the surgeon can program one channel with a test shock and the other channel with a much stronger, rescue shock. The independent capacitor arrays will automatically be charged to these two independent levels. In the lab, the test shock can be used to attempt defibrillation. If this test shock does not revert the fibrillation, the rescue shock can be delivered immediately. This is in sharp contrast to any existing device where 20 or 30 seconds might elapse before a rescue shock can be applied. A memory capability is also provided to instantly change the program settings of the two defibrillation channels to previously selected values. Since the charging of the high voltage capacitors is automatic, this provides an effective way to quickly change to a maximum energy setting if the initial two shocks fail to defibrillate the patient. A similar memory capability is included in the programmable stimulator. By this arrangement, when the electrophysiologist induces the patient's arrhythmia he can instantly go to a previously selected set of antitachycardia pacing parameters and thereby attempt to terminate the arrhythmia without the delay of further programming. As noted above with the prior art devices, if a test shock fails to defibrillate the patient, there is no information presented to the physician to help him alleviate the problem. The subject invention provides a means to calculate and display such information. More specifically, in conjunction with each defibrillation shock, the unit will display to the physician the actual energy, measured in joules, delivered to the patient, as well as the patient's electrical resistance. If the resistance is abnormal, this could indicate a problem with the electrode system. Without the displayed information, a physician might not be alerted to the problem thereby compromising patient's safety. In a preferred embodiment, the residual charge of the capacitor is measured and is used to calculate the energy delivered and patient resistance. As another aid to the physician, the subject invention also provides a means for calculating and displaying the energy which is estimated to be delivered during a defibrillation shock. The energy delivered will vary based on a variety of parameters, such as the voltage level, pulse width and patient resistance. All of these parameters are used by the apparatus to calculate the expected energy to be delivered. By this arrangement, the physician can best gauge the proper voltage and pulse width settings needed to deliver the desired energy level shock. Further objects and advantages of the subject invention can be appreciated by referring to the following detailed description taken in conjunction with the drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system block diagram of the apparatus of the subject invention. FIG. 2 is a diagram of the layout of the front panel of the apparatus, illustrating the various input systems and displays. FIG. 3 is a diagram of the rear panel of the apparatus of the subject invention. FIG. 4 is a flow chart illustrating the steps of delivering high voltage defibrillation shocks. FIG. 5 is a flow chart illustrating the automatic charging feature of the subject invention. FIG. 6 is a schematic diagram illustrating the high voltage regulator used to control and measure the energy in the storage capacitors. FIG. 7 is a flow chart illustrating the ability to display alternate parameters which are stored in memory. FIG. 8 is a flow chart illustrating the steps used to calculate and display energy and resistance. FIG. 9 is a flow chart illustrating the steps used to calculate and display of estimated energy. FIG. 10 is a schematic diagram of the high voltage protection circuit. FIG. 11 is a schematic diagram of the high voltage output circuit. FIG. 12 is a schematic diagram of the programmable stimulator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is illustrated a system block diagram of the apparatus 10 of the subject invention. The apparatus 10 is microprocessor controlled. In the preferred embodiment, 68HCII microprocessor, manufactured by Motorola, is used. A microprocessor board 20 includes standard components, such as a program ROM, RAM, bus drivers and latches. The front panel 22, which will be discussed in greater detail below, interfaces with the microprocessor board 20 through a support board 24. Support board 24 includes display drivers, switch decoders, an optical encoder, and other standard interface circuits. The microprocessor writes information to the display drivers and receives information through the optical encoder and switch matrix interfaces. The elements in boards 20 and 24 are standard and any suitable alternatives can be utilized. The subject apparatus includes six other principal boards which communicate with the microprocessor. A pair of high voltage regulator boards 30 and 32 are programmed by the microprocessor to charge the high voltage capacitors 34 and 36 to the voltage entered on the front panel 22 by the physician. Details of the high voltage regulators will be discussed below with reference to FIGS. 5 and 6. After defibrillation, data is read back from the regulator boards that contain information on energy delivered and the patient's electrical resistance. This function will be discussed below with reference to FIG. 8. Output boards 40 and 42 include high voltage electrical switches to connect patients to the high voltage energy storage capacitors through the rear panel 43 for the duration selected on the front panel 22 by the physician. The output boards will be discussed in greater detail in conjunction with FIG. 11. The subject apparatus further includes a programmable stimulator board 44. The programmable stimulator board also interfaces with the microprocessor 20 to generate the pulses that are programmed into the front panel by the physician. A more detailed description of the programmable stimulator board will be made with reference to FIG. 12. During a defibrillation attempt, the output from the programmable stimulator is protected through a circuit on board 46. If this protection were not available, the output of the stimulator 44 could be easily damaged. A more detailed description of the protection circuit will be made with reference to FIG. 10. The apparatus 10 is powered by a 12 volt rechargeable battery 50 connected to a power supply regulator board 52. Board 52 regulates the system power supply and provides a signal to the microprocessor board when the batteries need recharging. The operation of the subject apparatus 10 will be described now with reference to the front panel inputs shown in FIG. 2 along with various accompanying flow charts where necessary. In the preferred embodiment, the front panel includes an array of LCD displays, push-button switches and an optical encoder 60. The basic operation calls for the physician to depress the switch next to the parameter he wants to adjust. The selected switch lights up indicating that the optical encoder 60, labelled "parameter adjust", will control the associated parameter. By rotating the knob 60, the parameter next to the lighted switch will be varied. As can be seen from FIG. 2, the left portion of the front panel controls the defibrillator operation, while the right portion controls the programmable stimulator. All electrical hookups are routed to the rear panel 43 as shown in FIG. 3. The two channels of the programmable stimulator terminate in standard BNC connectors 62A and 62B (labelled CH1 and CH2). Used separately, pacing pulses can be delivered to different parts of the heart, although the outputs may be ganged together. The high voltage outputs 64A and 64B, (labelled P1 and P2) are high voltage connectors which can be left separate or can be shorted together using a toggle switch 66. When the outputs are shorted together, the output from both channels is delivered through the P1 output. FIG. 3 also shows an input 67 to receive a charge line to recharge the storage batteries. The charger is controlled by switch 68. In order to deliver the P1 shock, the physician refers to the LCD display block 69, labelled "OUTPUT" on the front panel. As illustrated in FIG. 2, P1 has been selected and is displayed in block 69. If P2 is displayed and the physician wants P1, he can press the output switch to toggle to P1. The "parameter select" switch below the output switch will be discussed in greater detail below. After the P1 shock has been selected, the electrophysiologist can verify that the voltage and pulse width are correct. This information is displayed in the top display block 70 of FIG. 2. As discussed above, these parameters can be adjusted by depressing the associated switch and rotating the encoder knob 60. If the parameters are changed, an automatic charging circuit discussed below will adjust the voltage in the capacitor bank to the proper level. When charging is complete, a ready light 72 will be illuminated, indicating that the charge can be delivered. In accordance with the subject invention, prior to initializing a test procedure, a second, rescue shock can also be programmed. In this case, the surgeon would also adjust the parameters for the P2 shock. In the illustrated embodiment, the parameters are shown in display block 74. In a typical situation, as illustrated herein, the second rescue shock will have significantly greater voltage and a longer pulse width since it would be assumed that the first defibrillation shock failed to revert the fibrillation. In use, the patient can be defibrillated by pressing the deliver switch 76 which will deliver the voltage stored in the Pl capacitor 34. If this shock fails to defibrillate the patient, the "OUTPUT" button is depressed causing the associated display to toggle to P2. The deliver button is then depressed and the energy in capacitor 36 will be immediately delivered. FIG. 4 is a flow diagram that describes the software in the microprocessor used to deliver the P1 and P2 charges. As shown therein, the front panel switches are continually scanned in steps 100 and 102. If any switch is pressed, priority is given to the deliver switch in step 104. If the deliver switch has not been depressed, the other switches will be serviced in step 105. If the deliver switch 76 is depressed, the outputs of the programmable stimulator will be protected via the disconnection step 106. The circuit 46 for disconnecting and protecting the programmable stimulator is shown in FIG. 10. Any signals from the stimulator must pass through this circuit before reaching the rear panel. Normally, the microprocessor leaves this circuit on by setting the ON/OFF line 140 to the RF oscillator 141 high. The RF oscillator 141 couples energy to the gates of the high voltage switches 142 (Motorola MTM5N100 MOSFETs) through a small pulse transformer 144. To turn the switches 142 off, the microprocessor sets the ON/OFF 140 line low, disabling the RF oscillator. The source-to-source connection of the MOSFETs along with the transformer isolation of the gate drives 146 results in a symmetric (+,-) 1000 volt protection. In this arrangement, the high voltage from the defibrillator pulse is not shunted back to the patient through the pacing leads since the disabled MOSFETs define an open circuit. This approach is therefore superior to a more simple shunt circuit, such as a Zener diode placed across the pacing leads. In the latter circuit, the stimulator would be protected, but the high voltage would be shunted to the pacing leads such that the characteristics of the defibrillation shock delivered would change, which can reduce efficiency and could damage heart tissue. The ground line from the programmable stimulator also goes through a set of protection switches to avoid defibrillation current shunting during high voltage output, as shown in FIG. 12. After the programmable stimulator is disconnected, the front panel parameters are checked in step 108 and the proper pulse width for the associated pulse is selected in steps 110A or 110B of FIG. 4. The microprocessor then commands the appropriate output board to connect the patient to the previously charged high voltage capacitor in step 112A or 112B. FIG. 11 is a block diagram of the output board 40 for capacitor Pl. To deliver a defibrillation pulse the microprocessor turns on the RF oscillator 150 for the programmed duration. The series-paralleled IGFETs 152 (Motorola MTP20N50) provide a 50 amp drive capability with low output leakage. While the RF oscillator 150 is on, the transformer 154 couples a square wave of voltage from its primary to its secondary. This voltage is rectified, and held by the gate capacitance of the IGFETs. When the RF oscillator is turned off, a pull down resistor 156 discharges the gate capacitance turning off the IGFETs. When the IGFETs are on, the ground connection is made to the patient through lead 158, and the high voltage capacitor is connected through the other lead 160. The current is led through high voltage diodes 162 in series with the patient. The diodes provide reverse voltage protection for the IGFETs. After the charge has been delivered and prior to the automatic recharging of the capacitor 36, the residual voltage on the capacitor is measured in step 130A or 130B. In the preferred embodiment, residual voltage is measured to permit the calculation of resistance and energy delivered to the patient as discussed in greater detail below. After the residual voltage has been measured, the capacitor is automatically recharged in step 132 shown in FIGS. 4 and 5. As can be appreciated, by having two independent programmable capacitor arrays, a test shock and a rescue shock of different voltages can be delivered with virtually no time delay therebetween. In use, the physician will observe whether the test shock has succeeded in defibrillating the patient and if that has failed, a second, higher voltage rescue shock will be delivered. Another unique aspect of the subject invention which reduces the time necessary to respond to a critical situation concerns the automatic recharging of the capacitors. As noted above, all prior art devices required that the voltage be set and thereafter a charge button be pressed to raise the capacitor bank to the desired level to avoid false triggering problems. In applicant's invention, as soon as the parameters are entered into the device, both the capacitor banks 34, 36 will be charged to their set levels. In addition, as soon as a shock is delivered, and after the residual voltage has been read, the capacitors will begin to immediately recharge. The steps taken by the microprocessor to carry out this automatic charging are shown in FIG. 5 and the regulator circuit itself is shown in FIG. 6. As shown in FIG. 5, the front panel parameters are continuously scanned in steps 200 and 202. If any parameters have been changed, the microprocessor will determine if the high voltage (P1 or P2) parameter has changed as shown in step 204. A change in the high voltage parameter could result from data entered via the optical encoder 60. The setting could also be changed as a result of pressing the parameter select switch 80A and will be discussed below. In any event, if the high voltage parameter has not changed, the other switches will be serviced as shown in step 206. If the high voltage parameter has changed, the processor will determine if it has increased in step 210. If the high voltage parameter has increased, the capacitor will be charged, while if the parameter has been decreased, the capacitor will be discharged. As shown in FIG. 5, if the capacitor has been discharged by delivering its energy to the patient, the processor will instruct the regulator board to charge the capacitor as indicated by the input 132, also shown in FIG. 4. If the capacitor is to be charged, charge line 260 on the regulator board shown in FIG. 6 will be set high. If the capacitor is to be discharged, discharge line 262 will be set high. In conjunction with setting the charge or discharge lines, the microprocessor will also load the voltage read from the selected switch (P1 or P2) into the digital to analog converter (DAC) 264 in step 216. A comparator 266 compares the high voltage from the storage capacitor (P1 or P2) to the output of the DAC 266. Note that the output from the capacitor bank is divided down through a resistor array 268 prior to entering the comparator. The output of comparator 266 is fed back to the microprocessor which detects when the output of the capacitor matches the output of the DAC 266 in step 218. The charging or discharging is then halted. As seen in the circuit diagram of FIG. 6, where the capacitor is being charged, low voltage from battery V BATT is supplied to a low to high voltage DC to DC converter 270 to charge the storage capacitor. As pointed out above, another unique advantage of the subject invention is the ability of the microprocessor to store a number of preset parameters. In this manner, the physician can program all the necessary parameters prior to initiating the surgical procedure. This ability is provided in both the programmable stimulator and defibrillator sections of the apparatus. As illustrated in the front panel in FIG. 2, both sides of the display include "SELECT" buttons 80A and 80B. By pressing either button, the display and electronics toggle between parameter set A and parameter set B. Each parameter set is independently adjustable and all the information is retained in the RAM on the microprocessor board 20. The steps taken by the microprocessor in relation to this selection process are shown in FIG. 7. More particularly, the front panel switches are scanned in steps 300 and 302. If a switch other than the select switch 80 is pressed, as determined in step 304, the other switches will be serviced as shown in step 305. If a select switch 80 has been pressed, the microprocessor determines what is currently being displayed in step 306. This current display is then changed in step 308A or 308B to the alternate set of parameters. The microprocessor also functions to reprogram the hardware in step 310. Thus, for example, in the defibrillator section, the voltages in the capacitors will be reprogrammed to the new P1 and P2 voltage levels. The recharging will be automatic, enabling the physician to respond quicker to a particular situation. It should be noted that the combination of the multiple storage parameters as well as the automatic charging feature and two channel capacitor array interact to improve patient care. More particularly, if a patient has gone into fibrillation, the physician can deliver a Pl pulse from parameter set A as a test shock. As soon as that shock has been delivered, the P1 capacitor begins recharging. If a surgeon determines that the first shock was insufficient to revert the fibrillation, the P2 shock from parameter set A can be given. If the P2 shock is also insufficient to revert the fibrillation, the physician can then select parameter set B. As noted above, prior to this selection the capacitors would already be recharging. The device would then have to merely complete the automatic recharging of the capacitors to the new levels of parameter set B and then the ready light will illuminate, permitting the physician to deliver a third shock. In the prior art devices, 20 or 30 seconds elapsed between each successive shock, whereas in the subject invention, this time period can be significantly reduced. The ability to enter and store two sets of parameters is also advantageous when using the programmable stimulator. As illustrated in block 84 of FIG. 2, a series of pulses have been programmed as parameter set A. As seen in block 85 all the pulses are programmed to have a 4.8 volt amplitude and a 0.45 millisecond pulse width. The parameter set A pulse series includes 8 pulses, each spaced 500 milliseconds apart (S1) followed by another pulse in 450 milliseconds (S2). The channel 2 pulses (which may be sent along the channel 1 line to the same spot in the heart) provide two more pulses each spaced apart at 400 and 350 milliseconds, respectively. This sequence is a typical of one intended to induce a tachycardia episode. Parameter set B can be programmed to have a series of pulses designed to revert the tachycardia. For example, a group of eight, similar pulses, spaced apart 300 milliseconds can be used to try to revert the tachycardia. The exact pulse train which is used to revert the tachycardia will vary based upon the patient. It should be noted, however, that the subject invention allows the physician great flexibility in programming the pulses. Furthermore, if the intended reversion pulses fail, the surgeon can immediately deliver a defibrillation pulse from the same device along the same leads. As noted above, in this case, the programmable stimulator leads will be automatically disconnected, preventing damage. The subject apparatus is also provided with a "PAUSE" switch 82 shown on the front panel in FIG. 2. When this switch is off, the series of pulses in block 84 will be delivered once, each time the start button 86 is depressed. If the pause switch is on, the series will be delivered repeatedly, every 10 seconds, giving time for the physician to alter the parameters in block 84 between each delivery. In this way, small changes can be made until a tachycardia is induced. Switch 87, labeled "S1", is used to set the number of S1 pulses which will be delivered. FIG. 12 is a simplified block diagram of the programmable stimulator. In operation, the microprocessor writes the desired pacing voltage to a DAC 320 in HEX format. The output of the DAC is buffered with an op-amp follower circuit 322 to increase its output current drive capability. When the START button 86 is pressed, the microprocessor paces the heart by sending a pulse of the programmed width (as selected on the front panel) to the PACE line 324. The pulse width is timed using the timer built into the 68HC11 microprocessor. After timing the first pulse, the microprocessor times the programmed pulse-to-pulse interval (500 msec for S1, as shown on the front panel; 450 msec for S2; etc.). After each pulse-to-pulse interval, the microprocessor stimulates the heart by activating the PACE line for the programmed pulse width. As described above, when defibrillating a patient, it is advantageous to provide the physician with information regarding the patient's resistance and the energy delivered by the pulse. This information is displayed in the front panel shown in FIG. 2 in blocks 88 and 90. This information could be derived, for example, by measuring the current delivered during defibrillation and then calculating the energy and resistance. In the preferred embodiment, energy and resistance are calculated by measuring the residual voltage on the discharge capacitor, as noted in step 130 of FIG. 4. Referring to FIG. 8, the steps taken by the microprocessor for calculating and displaying energy and resistance are illustrated. More specifically, after the high voltage is delivered in step 400, the residual voltage on the capacitor is measured. The residual voltage on the capacitor is measured by setting to low both the charge and discharge lines 260, 262 on the regulator board shown in FIG. 6. The residual voltage of the capacitor will be supplied to the positive lead on the comparator 266. The microprocessor then varies the output of the DAC 264 in a successive approximation fashion. More specifically, if the voltage output from DAC 264 is higher than the input from the capacitor, the comparator output will be low and the microprocessor will drop the voltage output of the DAC. If the new output from the DAC is not low enough to change the output from the comparator, further reductions in the output will be made until the comparator output toggles to high. Then the voltage from the DAC will be increased until the comparator output toggles back to low. This procedure will continue until a change in the least significant bit of the code to the DAC is enough to toggle the output of the comparator. At this point the code in the DAC represents the residual voltage on the capacitor voltage. After the residual voltage on the capacitor is measured, the microprocessor begins the recharging procedure 404 as discussed in detail with regard to FIGS. 5 and 6. The microprocessor will also calculate the energy and resistance delivered in step 406. The energy delivered in the shock can be calculated using the following equation: J=0.5C(Vi.sup.2 -Vf.sup.2) (1) where Vi equals the initial voltage, Vf the residual voltage, C the capacitance of the high voltage capacitor, ad J the energy delivered in joules. Resistance R can be calculated by the following equation: R=-PW/[(C) ln(Vf/Vi)] (2) when PW is the pulse width of the defibrillating shock. The energy and resistance are then displayed on the front panel as shown in step 408 and illustrated in FIG. 2 in blocks 88 and 90. By supplying the physician with the measured resistance and energy, intelligent decision making can be carried out regarding subsequent energy pulses. Clearly, if the resistance is much less than expected, it would indicate a short in the leads. In addition, a physician can note the actual energy delivered when preparing to deliver another shock at this or a subsequent point in time. As seen from FIG. 2, the front panel also includes a display block 92 for illustrating the estimated energy. This display is intended to supply the physician with information about the expected energy to be delivered if the pulse that is presently selected on the LCD output of the panel were to be delivered. In order to make this calculation, the physician must enter the expected resistance of the patient. Prior to any testing, this resistance will be set to a standard level. After some initial testing, the physician may be able to provide a more accurate number for this resistance. FIG. 9 illustrates the steps taken by the microprocessor to carry out this function. As in the previous flow diagrams, the microprocessor will scan the front panel parameters in steps 500 and 502. If none of the defibrillator panel switches have been changed, the other parameters switches can be serviced in step 504. However, if any of the defibrillator panel switches have been changed, a new estimated energy must be calculated. Note that any change entered by the physician to the expected resistance, pulse width or voltage level will initiate the calculation of a new estimated energy. The calculation of the estimated energy takes place in step 508. The estimated energy can be calculated by using Equation (1) above where Vf (which was previously the residual voltage measured on the capacitor) is now approximately Vf=(Vi)exp[-PW/RC] (3) The variables listed above are the same as those discussed with relation to the display of actual resistance and energy. The resulting energy in joules is then displayed on the front panel as shown in step 510. In summary, there has been provided a new and improved apparatus for assessing lethal ventricular tachyarrhythmia and in determining defibrillation thresholds. The subject invention advantageously combines a programmable stimulator with a defibrillator. The apparatus is provided with a number of features intended to improve operation, facilitating use by the physician and decreasing patient risk. Included in these improvements is an automatic charging circuit coupled with a dual channel capacitor defibrillator to substantially reduce the time to deliver a rescue shock if a test shock has failed. The subject system further includes ability to store multiple parameters enabling the unit to be preprogrammed prior to initiation of cardiac procedure. The unit also displays the energy and resistance present in a defibrillation shock. Finally, a display feature is also provided which gives information to the physician regarding the estimated energy of a pulse to be delivered having a specific voltage and pulse width. While the above apparatus has been described with reference to a preferred embodiment, it should be apparent that various changes and modifications could be made therein by one skilled in the art without varying from the scope and spirit of the subject invention as defined by the appended claims.
A combination two-channel defibrillator and programmable pacing stimulator for assesses lethal ventricular tachyarrhythmias and determine defibrillation thresholds during implantable defibrillator procedures. A pair of switching transistors are provided to protect the pacing circuit when a defibrillation shock is delivered. These switching transistors provide symmetric voltage protection and prevent the defibrillation energy from being shunted back to the patient through the pacing leads.
Summarize the patent document, focusing on the invention's functionality and advantages.
[ "TECHNICAL FIELD This invention relates to an apparatus for use in the field of cardiac electrophysiology.", "More specifically, an apparatus is disclosed for assessing ventricular tachyarrhythmias and determining defibrillation thresholds during implantable defibrillator procedures.", "BACKGROUND OF THE INVENTION In the United States, heart disease is a major health problem.", "Of the 1.5 million people per year who suffer a myocardial infarction, about 680,000 survive that have ischemia (dead heart tissue) which is the basis for cardiac arrhythmias.", "Approximately 400,000 people a year die from the most serious types of cardiac arrhythmias.", "Arrhythmias can be classified into three broad types.", "Bradycardia is an abnormally slow heart rhythm.", "This problem has been successfully treated for a number of years with implantable pacemakers which induce the heart to beat at a faster, normal rhythm.", "The remaining types of arrhythmias are more difficult to control.", "Tachycardia is a rapid cardiac rhythm generally defined as a heart rate greater than 100 beats per minute.", "There are normal physiologic tachycardias due to exertion or emotion as well as abnormal nonphysiologic tachycardias in which a high rate results in loss of blood pressure.", "Sustained ventricular tachycardia can result in severe loss of blood pressure, loss of consciousness and can deteriorate into ventricular fibrillation which is fatal if not quickly interrupted.", "Fibrillation, unlike tachycardia, is a disorganized cardiac rhythm wherein the heart quivers rather than beats.", "This quivering is a result of multiple waves of cardiac depolarization spreading and colliding throughout the ventricular tissue.", "Ventricular fibrillation results in a precipitous decrease in blood pressure followed quickly by brain damage and death.", "Arrhythmias are treated using either medication, surgery or implantation of a medical device.", "Drug therapy is employed initially in the majority of cases and involves the use of various medications to prevent an arrhythmia from starting or being sustained.", "The main advantage of drug therapy is that no surgical intervention is required.", "The major drawback to the exclusive use of therapy is the lack of backup therapy to terminate a potentially lethal arrhythmia should the drug eventually fail to prevent the arrhythmia from recurring.", "Additionally, in attempting to achieve adequate tachycardia prevention, drug related side effects often preclude using an adequate dose of medication.", "Surgery involves locating the cause of the arrhythmia and removing or isolating it from the healthy cardiac tissue.", "The advantage of surgical therapy is that the procedure is curative when successful.", "The disadvantage of surgical therapy is the morbidity and mortality associated with open heart surgery and the technical difficulty and high cost of the procedure.", "These factors have restricted the practice of antiarrhythmia surgery.", "In 1980, the first implantable defibrillator was implanted in a human patient.", "Implantable defibrillators sense fibrillation and automatically deliver a high energy pulse.", "Subsequent studies have indicated that these devices are effective in preventing sudden death from fibrillation.", "Presently, no single implantable device has been developed to control all three types of arrhythmias.", "The analysis of patients who have arrhythmias often requires invasive testing in an electrophysiology lab.", "This invasive testing is carried out in a variety of situations.", "For example, invasive testing is common during a selection process used to determine which patients might be candidates for implantable defibrillators.", "Invasive testing is also utilized in trying to assess and characterize tachycardia which is then treated with drugs.", "In any case, in the testing process, catheters are inserted into the heart and the patient's arrhythmia is provoked with programmed electrical stimulation.", "When the arrhythmia manifests itself, the physician attempts to terminate it with antitachycardia pacing.", "Antitachycardia pacing is described in the literature and consists of a series of low voltage pulses designed to reset the normal heartbeat.", "If pacing fails, the patient is either cardioverted with a substantially higher voltage shock or defibrillated with a very high voltage energy pulse.", "Low energy cardioversion utilizes pulses with energy levels far greater than pacing pulses but lower than high energy defibrillation pulses.", "With energies of less than 5 joules, this mode of therapy is based on the theory of interrupting the arrhythmia by stimulating the tissue, rendering it nonexcitable.", "Low energy cardioversion has been clinically demonstrated as effective.", "Its drawbacks include patient discomfort and the fact that improperly timed pulses can accelerate tachycardias and occasionally induce fibrillation.", "In contrast, high energy defibrillation uses pulses with energy levels tens of thousands of times greater than pacemaker pulses.", "High energy defibrillation is accomplished by stimulating a large portion of the ventricular tissues simultaneously and rendering it nonexcitable, thereby terminating the arrhythmia.", "If a patient is found suitable, an internal defibrillator can be implanted to control the arrhythmia.", "During the operation, the patient's defibrillation threshold must be determined.", "First, the patient is fibrillated using a programmable stimulator, then a special defibrillator is used to determine the energy required to defibrillate the patient.", "The invention described herein facilitates the assessment of arrhythmias and defibrillation thresholds resulting in improved patient care and substantially decreased patient risk.", "In the prior art, there existed both programmable stimulators and cardioversion/defibrillator devices.", "The programmable stimulator includes a means to pace the patient's heart with critically timed stimuli to provoke the cardiac arrhythmia.", "These devices are then used to terminate the arrhythmia using antitachycardia pacing.", "If the pacing accelerates the arrhythmia or fails to terminate it, then a standby defibrillator device must be set up and the patient cardioverted or defibrillated.", "Frequently, the patient is cardioverted or defibrillated externally.", "More recently, internal catheters have been provided to deliver the defibrillation shock.", "As noted above, an external cardioverter/defibrillator is used during implantable defibrillator procedures to assess the patient's cardioversion/defibrillation threshold.", "When the patient is fibrillated using a programmable stimulator, the unit must be disconnected before a test defibrillation pulse can be applied.", "Frequently, the test pulse fails to defibrillate the patient.", "Once the physician recognizes the failure to defibrillate, he must program a new, higher voltage rescue shock into the defibrillator.", "The unit must then recharge prior to delivery of the rescue shock.", "This procedure takes considerable time and there is ample opportunity for operator error.", "Any delay in defibrillating the patient is a serious health risk and improving the response time to the delivery of the rescue shock substantially reduces patient risk.", "Accordingly, it would be desirable to eliminate any unnecessary time between delivery of the test shock and rescue shock.", "In the above described procedures, it is also clear that in the electrophysiology lab, it is frequently necessary to use both a programmable stimulator and a cardioverter/defibrillator.", "Present day equipment requires the operator to switch leads and move back and forth between two pieces of equipment.", "During this procedure, care must be taken to prevent any of the high voltage charge delivered by the defibrillator from reaching the output leads of the programmable stimulator to avoid damaging the latter.", "Accordingly, it would be desirable to provide a single combination test unit wherein leads would not have to be changed and automatic protection of programmable stimulator would be provided.", "Another drawback of the defibrillation devices available in the prior art relates to the fact that little or no measurement and visual feedback is given to the surgeon regarding the defibrillation pulse.", "More specifically, the surgeon typically sets a pulse width and a voltage level for a test shock.", "If this test shock fails, the surgeon cannot be sure whether it was the result of shorted leads, an unexpectedly high resistance in the heart or whether the voltage was just too low to stop the defibrillation.", "There presently exists some low voltage pacing devices which have been designed to provide additional information to the surgeon regarding patient resistance and energy delivered.", "However, to date, no systems have been provided to calculate and display this information in a defibrillation setting.", "In a life-threatening situation, such as cardiac fibrillation, such information is extremely important and can aid the surgeon in assessing the type of rescue shock necessary to end the fibrillation.", "The energy delivered to the heart of a patient is generally measured in joules.", "The energy level of the shock is analogous to a dosage in therapy.", "In prior art devices, as in the subject invention, the surgeon sets the defibrillation shock by adjusting a voltage level and the pulse width.", "However, in the prior art devices, no information is given to the physician as to the energy which will be received by the patient if a shock with those set parameters were delivered.", "Therefore, it would be desirable to provide a device which displays the estimated energy based on the set voltage level and pulse width.", "Accordingly, it is an object of the subject invention to provide a new and improved apparatus for electrophysiology testing in patients suffering from severe ventricular arrhythmias.", "It is another object of the subject invention to provide a new and improved apparatus which advantageously combines a programmable stimulator and an internal cardioversion/defibrillation device.", "It is a further object of the subject invention to provide a combination stimulator/defibrillator apparatus with automatic circuit protection for the stimulator.", "It is a still another object of the subject invention to provide a new and improved defibrillator which includes a pair of capacitor banks permitting the simultaneous storage of both a test shock and a rescue shock.", "It is still a further object of the subject invention to provide a new and improved defibrillator apparatus which includes automatic recharge circuitry to reduce the time necessary to deliver a rescue shock during an emergency procedure.", "It is still another object of the subject invention to provide a new and improved apparatus which allows multiple, independent entries of data which are stored for later recall during testing procedures.", "It is still a further object of the subject invention to provide a new and improved defibrillator apparatus which will display measurement of resistance and energy delivered during a defibrillation shock.", "It is still a another object of the subject invention to provide a new and improved defibrillator apparatus which will display the energy which is estimated to be delivered if a shock of a given voltage and pulse width is to be delivered.", "SUMMARY OF THE INVENTION In accordance with these and many other objects, the subject invention provides a single device that can be used in electrophysiology labs during ventricular tachycardia procedures.", "The invention integrates an innovative two-channel defibrillator with a programmable stimulator in a manner that enhances response time to the patient and provides more information to the surgeon.", "A number of new features have been included which address unique problems encountered when treating severe arrhythmia.", "In use, an indwelling defibrillating catheter with pacing capabilities is inserted into the heart.", "In this manner, the arrhythmia can be induced by the subject apparatus and, if necessary, the patient can be defibrillated within seconds of the initiation of the arrhythmia.", "In accordance with the subject invention an automatic interrupt means is provided to protect the delicate circuits of the stimulator from the high voltage discharge delivered by the defibrillator without shunting current to the patient.", "Another advantage of the unique combination found in the subject invention is that the time necessary to initiate defibrillation is much shorter than is currently possible, resulting in decreased patient risk.", "To enhance the rapidity of defibrillation, the unit always remains charged to the programmed defibrillating voltages.", "Devices which exist in the prior art all have a charge button that must be pressed to initiate the charging of the storage capacitors.", "This feature was generally provided because the devices were subject to false triggering wherein the high voltage would be released inadvertently.", "In recent years, more reliable equipment has been developed which is not subject to false triggering.", "Nonetheless, the prior art devices still incorporate both a charge button (which is depressed to load the capacitor ) and a separate switch, which must be subsequently depressed, to the deliver the shock after the capacitor has been charged.", "In the emergency situation of a patient fibrillation event, the additional step of having to press a charge button can be delayed or overlooked.", "Even if the charge button is properly pressed, time will elapse before the capacitor bank is raised to the level of the desired shock.", "In the subject invention, the charge button is eliminated and an automatic circuit is provided to maintain the capacitor banks at the set voltage level.", "The defibrillation circuitry of the subject apparatus includes two independent channels.", "Each channel includes its own storage capacitors which can be independently programmed.", "Prior to a surgical procedure, the surgeon can program one channel with a test shock and the other channel with a much stronger, rescue shock.", "The independent capacitor arrays will automatically be charged to these two independent levels.", "In the lab, the test shock can be used to attempt defibrillation.", "If this test shock does not revert the fibrillation, the rescue shock can be delivered immediately.", "This is in sharp contrast to any existing device where 20 or 30 seconds might elapse before a rescue shock can be applied.", "A memory capability is also provided to instantly change the program settings of the two defibrillation channels to previously selected values.", "Since the charging of the high voltage capacitors is automatic, this provides an effective way to quickly change to a maximum energy setting if the initial two shocks fail to defibrillate the patient.", "A similar memory capability is included in the programmable stimulator.", "By this arrangement, when the electrophysiologist induces the patient's arrhythmia he can instantly go to a previously selected set of antitachycardia pacing parameters and thereby attempt to terminate the arrhythmia without the delay of further programming.", "As noted above with the prior art devices, if a test shock fails to defibrillate the patient, there is no information presented to the physician to help him alleviate the problem.", "The subject invention provides a means to calculate and display such information.", "More specifically, in conjunction with each defibrillation shock, the unit will display to the physician the actual energy, measured in joules, delivered to the patient, as well as the patient's electrical resistance.", "If the resistance is abnormal, this could indicate a problem with the electrode system.", "Without the displayed information, a physician might not be alerted to the problem thereby compromising patient's safety.", "In a preferred embodiment, the residual charge of the capacitor is measured and is used to calculate the energy delivered and patient resistance.", "As another aid to the physician, the subject invention also provides a means for calculating and displaying the energy which is estimated to be delivered during a defibrillation shock.", "The energy delivered will vary based on a variety of parameters, such as the voltage level, pulse width and patient resistance.", "All of these parameters are used by the apparatus to calculate the expected energy to be delivered.", "By this arrangement, the physician can best gauge the proper voltage and pulse width settings needed to deliver the desired energy level shock.", "Further objects and advantages of the subject invention can be appreciated by referring to the following detailed description taken in conjunction with the drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system block diagram of the apparatus of the subject invention.", "FIG. 2 is a diagram of the layout of the front panel of the apparatus, illustrating the various input systems and displays.", "FIG. 3 is a diagram of the rear panel of the apparatus of the subject invention.", "FIG. 4 is a flow chart illustrating the steps of delivering high voltage defibrillation shocks.", "FIG. 5 is a flow chart illustrating the automatic charging feature of the subject invention.", "FIG. 6 is a schematic diagram illustrating the high voltage regulator used to control and measure the energy in the storage capacitors.", "FIG. 7 is a flow chart illustrating the ability to display alternate parameters which are stored in memory.", "FIG. 8 is a flow chart illustrating the steps used to calculate and display energy and resistance.", "FIG. 9 is a flow chart illustrating the steps used to calculate and display of estimated energy.", "FIG. 10 is a schematic diagram of the high voltage protection circuit.", "FIG. 11 is a schematic diagram of the high voltage output circuit.", "FIG. 12 is a schematic diagram of the programmable stimulator.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is illustrated a system block diagram of the apparatus 10 of the subject invention.", "The apparatus 10 is microprocessor controlled.", "In the preferred embodiment, 68HCII microprocessor, manufactured by Motorola, is used.", "A microprocessor board 20 includes standard components, such as a program ROM, RAM, bus drivers and latches.", "The front panel 22, which will be discussed in greater detail below, interfaces with the microprocessor board 20 through a support board 24.", "Support board 24 includes display drivers, switch decoders, an optical encoder, and other standard interface circuits.", "The microprocessor writes information to the display drivers and receives information through the optical encoder and switch matrix interfaces.", "The elements in boards 20 and 24 are standard and any suitable alternatives can be utilized.", "The subject apparatus includes six other principal boards which communicate with the microprocessor.", "A pair of high voltage regulator boards 30 and 32 are programmed by the microprocessor to charge the high voltage capacitors 34 and 36 to the voltage entered on the front panel 22 by the physician.", "Details of the high voltage regulators will be discussed below with reference to FIGS. 5 and 6.", "After defibrillation, data is read back from the regulator boards that contain information on energy delivered and the patient's electrical resistance.", "This function will be discussed below with reference to FIG. 8. Output boards 40 and 42 include high voltage electrical switches to connect patients to the high voltage energy storage capacitors through the rear panel 43 for the duration selected on the front panel 22 by the physician.", "The output boards will be discussed in greater detail in conjunction with FIG. 11.", "The subject apparatus further includes a programmable stimulator board 44.", "The programmable stimulator board also interfaces with the microprocessor 20 to generate the pulses that are programmed into the front panel by the physician.", "A more detailed description of the programmable stimulator board will be made with reference to FIG. 12.", "During a defibrillation attempt, the output from the programmable stimulator is protected through a circuit on board 46.", "If this protection were not available, the output of the stimulator 44 could be easily damaged.", "A more detailed description of the protection circuit will be made with reference to FIG. 10.", "The apparatus 10 is powered by a 12 volt rechargeable battery 50 connected to a power supply regulator board 52.", "Board 52 regulates the system power supply and provides a signal to the microprocessor board when the batteries need recharging.", "The operation of the subject apparatus 10 will be described now with reference to the front panel inputs shown in FIG. 2 along with various accompanying flow charts where necessary.", "In the preferred embodiment, the front panel includes an array of LCD displays, push-button switches and an optical encoder 60.", "The basic operation calls for the physician to depress the switch next to the parameter he wants to adjust.", "The selected switch lights up indicating that the optical encoder 60, labelled "parameter adjust", will control the associated parameter.", "By rotating the knob 60, the parameter next to the lighted switch will be varied.", "As can be seen from FIG. 2, the left portion of the front panel controls the defibrillator operation, while the right portion controls the programmable stimulator.", "All electrical hookups are routed to the rear panel 43 as shown in FIG. 3. The two channels of the programmable stimulator terminate in standard BNC connectors 62A and 62B (labelled CH1 and CH2).", "Used separately, pacing pulses can be delivered to different parts of the heart, although the outputs may be ganged together.", "The high voltage outputs 64A and 64B, (labelled P1 and P2) are high voltage connectors which can be left separate or can be shorted together using a toggle switch 66.", "When the outputs are shorted together, the output from both channels is delivered through the P1 output.", "FIG. 3 also shows an input 67 to receive a charge line to recharge the storage batteries.", "The charger is controlled by switch 68.", "In order to deliver the P1 shock, the physician refers to the LCD display block 69, labelled "OUTPUT"", "on the front panel.", "As illustrated in FIG. 2, P1 has been selected and is displayed in block 69.", "If P2 is displayed and the physician wants P1, he can press the output switch to toggle to P1.", "The "parameter select"", "switch below the output switch will be discussed in greater detail below.", "After the P1 shock has been selected, the electrophysiologist can verify that the voltage and pulse width are correct.", "This information is displayed in the top display block 70 of FIG. 2. As discussed above, these parameters can be adjusted by depressing the associated switch and rotating the encoder knob 60.", "If the parameters are changed, an automatic charging circuit discussed below will adjust the voltage in the capacitor bank to the proper level.", "When charging is complete, a ready light 72 will be illuminated, indicating that the charge can be delivered.", "In accordance with the subject invention, prior to initializing a test procedure, a second, rescue shock can also be programmed.", "In this case, the surgeon would also adjust the parameters for the P2 shock.", "In the illustrated embodiment, the parameters are shown in display block 74.", "In a typical situation, as illustrated herein, the second rescue shock will have significantly greater voltage and a longer pulse width since it would be assumed that the first defibrillation shock failed to revert the fibrillation.", "In use, the patient can be defibrillated by pressing the deliver switch 76 which will deliver the voltage stored in the Pl capacitor 34.", "If this shock fails to defibrillate the patient, the "OUTPUT"", "button is depressed causing the associated display to toggle to P2.", "The deliver button is then depressed and the energy in capacitor 36 will be immediately delivered.", "FIG. 4 is a flow diagram that describes the software in the microprocessor used to deliver the P1 and P2 charges.", "As shown therein, the front panel switches are continually scanned in steps 100 and 102.", "If any switch is pressed, priority is given to the deliver switch in step 104.", "If the deliver switch has not been depressed, the other switches will be serviced in step 105.", "If the deliver switch 76 is depressed, the outputs of the programmable stimulator will be protected via the disconnection step 106.", "The circuit 46 for disconnecting and protecting the programmable stimulator is shown in FIG. 10.", "Any signals from the stimulator must pass through this circuit before reaching the rear panel.", "Normally, the microprocessor leaves this circuit on by setting the ON/OFF line 140 to the RF oscillator 141 high.", "The RF oscillator 141 couples energy to the gates of the high voltage switches 142 (Motorola MTM5N100 MOSFETs) through a small pulse transformer 144.", "To turn the switches 142 off, the microprocessor sets the ON/OFF 140 line low, disabling the RF oscillator.", "The source-to-source connection of the MOSFETs along with the transformer isolation of the gate drives 146 results in a symmetric (+,-) 1000 volt protection.", "In this arrangement, the high voltage from the defibrillator pulse is not shunted back to the patient through the pacing leads since the disabled MOSFETs define an open circuit.", "This approach is therefore superior to a more simple shunt circuit, such as a Zener diode placed across the pacing leads.", "In the latter circuit, the stimulator would be protected, but the high voltage would be shunted to the pacing leads such that the characteristics of the defibrillation shock delivered would change, which can reduce efficiency and could damage heart tissue.", "The ground line from the programmable stimulator also goes through a set of protection switches to avoid defibrillation current shunting during high voltage output, as shown in FIG. 12.", "After the programmable stimulator is disconnected, the front panel parameters are checked in step 108 and the proper pulse width for the associated pulse is selected in steps 110A or 110B of FIG. 4. The microprocessor then commands the appropriate output board to connect the patient to the previously charged high voltage capacitor in step 112A or 112B.", "FIG. 11 is a block diagram of the output board 40 for capacitor Pl.", "To deliver a defibrillation pulse the microprocessor turns on the RF oscillator 150 for the programmed duration.", "The series-paralleled IGFETs 152 (Motorola MTP20N50) provide a 50 amp drive capability with low output leakage.", "While the RF oscillator 150 is on, the transformer 154 couples a square wave of voltage from its primary to its secondary.", "This voltage is rectified, and held by the gate capacitance of the IGFETs.", "When the RF oscillator is turned off, a pull down resistor 156 discharges the gate capacitance turning off the IGFETs.", "When the IGFETs are on, the ground connection is made to the patient through lead 158, and the high voltage capacitor is connected through the other lead 160.", "The current is led through high voltage diodes 162 in series with the patient.", "The diodes provide reverse voltage protection for the IGFETs.", "After the charge has been delivered and prior to the automatic recharging of the capacitor 36, the residual voltage on the capacitor is measured in step 130A or 130B.", "In the preferred embodiment, residual voltage is measured to permit the calculation of resistance and energy delivered to the patient as discussed in greater detail below.", "After the residual voltage has been measured, the capacitor is automatically recharged in step 132 shown in FIGS. 4 and 5.", "As can be appreciated, by having two independent programmable capacitor arrays, a test shock and a rescue shock of different voltages can be delivered with virtually no time delay therebetween.", "In use, the physician will observe whether the test shock has succeeded in defibrillating the patient and if that has failed, a second, higher voltage rescue shock will be delivered.", "Another unique aspect of the subject invention which reduces the time necessary to respond to a critical situation concerns the automatic recharging of the capacitors.", "As noted above, all prior art devices required that the voltage be set and thereafter a charge button be pressed to raise the capacitor bank to the desired level to avoid false triggering problems.", "In applicant's invention, as soon as the parameters are entered into the device, both the capacitor banks 34, 36 will be charged to their set levels.", "In addition, as soon as a shock is delivered, and after the residual voltage has been read, the capacitors will begin to immediately recharge.", "The steps taken by the microprocessor to carry out this automatic charging are shown in FIG. 5 and the regulator circuit itself is shown in FIG. 6. As shown in FIG. 5, the front panel parameters are continuously scanned in steps 200 and 202.", "If any parameters have been changed, the microprocessor will determine if the high voltage (P1 or P2) parameter has changed as shown in step 204.", "A change in the high voltage parameter could result from data entered via the optical encoder 60.", "The setting could also be changed as a result of pressing the parameter select switch 80A and will be discussed below.", "In any event, if the high voltage parameter has not changed, the other switches will be serviced as shown in step 206.", "If the high voltage parameter has changed, the processor will determine if it has increased in step 210.", "If the high voltage parameter has increased, the capacitor will be charged, while if the parameter has been decreased, the capacitor will be discharged.", "As shown in FIG. 5, if the capacitor has been discharged by delivering its energy to the patient, the processor will instruct the regulator board to charge the capacitor as indicated by the input 132, also shown in FIG. 4. If the capacitor is to be charged, charge line 260 on the regulator board shown in FIG. 6 will be set high.", "If the capacitor is to be discharged, discharge line 262 will be set high.", "In conjunction with setting the charge or discharge lines, the microprocessor will also load the voltage read from the selected switch (P1 or P2) into the digital to analog converter (DAC) 264 in step 216.", "A comparator 266 compares the high voltage from the storage capacitor (P1 or P2) to the output of the DAC 266.", "Note that the output from the capacitor bank is divided down through a resistor array 268 prior to entering the comparator.", "The output of comparator 266 is fed back to the microprocessor which detects when the output of the capacitor matches the output of the DAC 266 in step 218.", "The charging or discharging is then halted.", "As seen in the circuit diagram of FIG. 6, where the capacitor is being charged, low voltage from battery V BATT is supplied to a low to high voltage DC to DC converter 270 to charge the storage capacitor.", "As pointed out above, another unique advantage of the subject invention is the ability of the microprocessor to store a number of preset parameters.", "In this manner, the physician can program all the necessary parameters prior to initiating the surgical procedure.", "This ability is provided in both the programmable stimulator and defibrillator sections of the apparatus.", "As illustrated in the front panel in FIG. 2, both sides of the display include "SELECT"", "buttons 80A and 80B.", "By pressing either button, the display and electronics toggle between parameter set A and parameter set B. Each parameter set is independently adjustable and all the information is retained in the RAM on the microprocessor board 20.", "The steps taken by the microprocessor in relation to this selection process are shown in FIG. 7. More particularly, the front panel switches are scanned in steps 300 and 302.", "If a switch other than the select switch 80 is pressed, as determined in step 304, the other switches will be serviced as shown in step 305.", "If a select switch 80 has been pressed, the microprocessor determines what is currently being displayed in step 306.", "This current display is then changed in step 308A or 308B to the alternate set of parameters.", "The microprocessor also functions to reprogram the hardware in step 310.", "Thus, for example, in the defibrillator section, the voltages in the capacitors will be reprogrammed to the new P1 and P2 voltage levels.", "The recharging will be automatic, enabling the physician to respond quicker to a particular situation.", "It should be noted that the combination of the multiple storage parameters as well as the automatic charging feature and two channel capacitor array interact to improve patient care.", "More particularly, if a patient has gone into fibrillation, the physician can deliver a Pl pulse from parameter set A as a test shock.", "As soon as that shock has been delivered, the P1 capacitor begins recharging.", "If a surgeon determines that the first shock was insufficient to revert the fibrillation, the P2 shock from parameter set A can be given.", "If the P2 shock is also insufficient to revert the fibrillation, the physician can then select parameter set B. As noted above, prior to this selection the capacitors would already be recharging.", "The device would then have to merely complete the automatic recharging of the capacitors to the new levels of parameter set B and then the ready light will illuminate, permitting the physician to deliver a third shock.", "In the prior art devices, 20 or 30 seconds elapsed between each successive shock, whereas in the subject invention, this time period can be significantly reduced.", "The ability to enter and store two sets of parameters is also advantageous when using the programmable stimulator.", "As illustrated in block 84 of FIG. 2, a series of pulses have been programmed as parameter set A. As seen in block 85 all the pulses are programmed to have a 4.8 volt amplitude and a 0.45 millisecond pulse width.", "The parameter set A pulse series includes 8 pulses, each spaced 500 milliseconds apart (S1) followed by another pulse in 450 milliseconds (S2).", "The channel 2 pulses (which may be sent along the channel 1 line to the same spot in the heart) provide two more pulses each spaced apart at 400 and 350 milliseconds, respectively.", "This sequence is a typical of one intended to induce a tachycardia episode.", "Parameter set B can be programmed to have a series of pulses designed to revert the tachycardia.", "For example, a group of eight, similar pulses, spaced apart 300 milliseconds can be used to try to revert the tachycardia.", "The exact pulse train which is used to revert the tachycardia will vary based upon the patient.", "It should be noted, however, that the subject invention allows the physician great flexibility in programming the pulses.", "Furthermore, if the intended reversion pulses fail, the surgeon can immediately deliver a defibrillation pulse from the same device along the same leads.", "As noted above, in this case, the programmable stimulator leads will be automatically disconnected, preventing damage.", "The subject apparatus is also provided with a "PAUSE"", "switch 82 shown on the front panel in FIG. 2. When this switch is off, the series of pulses in block 84 will be delivered once, each time the start button 86 is depressed.", "If the pause switch is on, the series will be delivered repeatedly, every 10 seconds, giving time for the physician to alter the parameters in block 84 between each delivery.", "In this way, small changes can be made until a tachycardia is induced.", "Switch 87, labeled "S1", is used to set the number of S1 pulses which will be delivered.", "FIG. 12 is a simplified block diagram of the programmable stimulator.", "In operation, the microprocessor writes the desired pacing voltage to a DAC 320 in HEX format.", "The output of the DAC is buffered with an op-amp follower circuit 322 to increase its output current drive capability.", "When the START button 86 is pressed, the microprocessor paces the heart by sending a pulse of the programmed width (as selected on the front panel) to the PACE line 324.", "The pulse width is timed using the timer built into the 68HC11 microprocessor.", "After timing the first pulse, the microprocessor times the programmed pulse-to-pulse interval (500 msec for S1, as shown on the front panel;", "450 msec for S2;", "etc.).", "After each pulse-to-pulse interval, the microprocessor stimulates the heart by activating the PACE line for the programmed pulse width.", "As described above, when defibrillating a patient, it is advantageous to provide the physician with information regarding the patient's resistance and the energy delivered by the pulse.", "This information is displayed in the front panel shown in FIG. 2 in blocks 88 and 90.", "This information could be derived, for example, by measuring the current delivered during defibrillation and then calculating the energy and resistance.", "In the preferred embodiment, energy and resistance are calculated by measuring the residual voltage on the discharge capacitor, as noted in step 130 of FIG. 4. Referring to FIG. 8, the steps taken by the microprocessor for calculating and displaying energy and resistance are illustrated.", "More specifically, after the high voltage is delivered in step 400, the residual voltage on the capacitor is measured.", "The residual voltage on the capacitor is measured by setting to low both the charge and discharge lines 260, 262 on the regulator board shown in FIG. 6. The residual voltage of the capacitor will be supplied to the positive lead on the comparator 266.", "The microprocessor then varies the output of the DAC 264 in a successive approximation fashion.", "More specifically, if the voltage output from DAC 264 is higher than the input from the capacitor, the comparator output will be low and the microprocessor will drop the voltage output of the DAC.", "If the new output from the DAC is not low enough to change the output from the comparator, further reductions in the output will be made until the comparator output toggles to high.", "Then the voltage from the DAC will be increased until the comparator output toggles back to low.", "This procedure will continue until a change in the least significant bit of the code to the DAC is enough to toggle the output of the comparator.", "At this point the code in the DAC represents the residual voltage on the capacitor voltage.", "After the residual voltage on the capacitor is measured, the microprocessor begins the recharging procedure 404 as discussed in detail with regard to FIGS. 5 and 6.", "The microprocessor will also calculate the energy and resistance delivered in step 406.", "The energy delivered in the shock can be calculated using the following equation: J=0.5C(Vi.", "sup[.", "].2 -Vf.", "sup[.", "].2) (1) where Vi equals the initial voltage, Vf the residual voltage, C the capacitance of the high voltage capacitor, ad J the energy delivered in joules.", "Resistance R can be calculated by the following equation: R=-PW/[(C) ln(Vf/Vi)] (2) when PW is the pulse width of the defibrillating shock.", "The energy and resistance are then displayed on the front panel as shown in step 408 and illustrated in FIG. 2 in blocks 88 and 90.", "By supplying the physician with the measured resistance and energy, intelligent decision making can be carried out regarding subsequent energy pulses.", "Clearly, if the resistance is much less than expected, it would indicate a short in the leads.", "In addition, a physician can note the actual energy delivered when preparing to deliver another shock at this or a subsequent point in time.", "As seen from FIG. 2, the front panel also includes a display block 92 for illustrating the estimated energy.", "This display is intended to supply the physician with information about the expected energy to be delivered if the pulse that is presently selected on the LCD output of the panel were to be delivered.", "In order to make this calculation, the physician must enter the expected resistance of the patient.", "Prior to any testing, this resistance will be set to a standard level.", "After some initial testing, the physician may be able to provide a more accurate number for this resistance.", "FIG. 9 illustrates the steps taken by the microprocessor to carry out this function.", "As in the previous flow diagrams, the microprocessor will scan the front panel parameters in steps 500 and 502.", "If none of the defibrillator panel switches have been changed, the other parameters switches can be serviced in step 504.", "However, if any of the defibrillator panel switches have been changed, a new estimated energy must be calculated.", "Note that any change entered by the physician to the expected resistance, pulse width or voltage level will initiate the calculation of a new estimated energy.", "The calculation of the estimated energy takes place in step 508.", "The estimated energy can be calculated by using Equation (1) above where Vf (which was previously the residual voltage measured on the capacitor) is now approximately Vf=(Vi)exp[-PW/RC] (3) The variables listed above are the same as those discussed with relation to the display of actual resistance and energy.", "The resulting energy in joules is then displayed on the front panel as shown in step 510.", "In summary, there has been provided a new and improved apparatus for assessing lethal ventricular tachyarrhythmia and in determining defibrillation thresholds.", "The subject invention advantageously combines a programmable stimulator with a defibrillator.", "The apparatus is provided with a number of features intended to improve operation, facilitating use by the physician and decreasing patient risk.", "Included in these improvements is an automatic charging circuit coupled with a dual channel capacitor defibrillator to substantially reduce the time to deliver a rescue shock if a test shock has failed.", "The subject system further includes ability to store multiple parameters enabling the unit to be preprogrammed prior to initiation of cardiac procedure.", "The unit also displays the energy and resistance present in a defibrillation shock.", "Finally, a display feature is also provided which gives information to the physician regarding the estimated energy of a pulse to be delivered having a specific voltage and pulse width.", "While the above apparatus has been described with reference to a preferred embodiment, it should be apparent that various changes and modifications could be made therein by one skilled in the art without varying from the scope and spirit of the subject invention as defined by the appended claims." ]
CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation-in-part of U.S. application Ser. No. 09/531,265, filed on Mar. 20, 2000, the contents of which are incorporated by reference herein in their entirety. FIELD OF THE INVENTION [0002] The invention relates to a process for the fermentative preparation of L-amino acids, in particular L-lysine, L-threonine, L-isoleucine and L-tryptophan, using coryneform bacteria in which at least the enzyme 6-phosphogluconate dehydrogenase encoded by the gnd gene is amplified. BACKGROUND [0003] L-Amino acids are used in animal nutrition, in human medicine and in the pharmaceuticals industry and are prepared by fermentation from strains of coryneform bacteria, in particular Corynebacterium glutamicum . Because of their great importance, work is constantly being undertaken to improve the preparation processes. Improvements may relate to fermentation measures, e.g., stirring and supply of oxygen; the composition of the nutrient media, e.g., the sugar concentration during the fermentation; the working up to the product form, e.g., by ion exchange chromatography; or the intrinsic output properties of the microorganism itself. [0004] Methods of mutagenesis, selection and mutant selection are used to improve the output properties of these microorganisms. Strains which are resistant to antimetabolites (e.g., the threonine analogue α-amino-β-hydroxyvaleric acid (AHV), and the lysine analogue S-(2-aminoethyl)-L-cystein (AEC)) or which are auxotrophic for metabolites of regulatory importance and produce L-amino acids such as threonine `or lysine are obtained in this manner. [0005] Methods utilizing recombinant DNA techniques have also been employed for some years for improving Corynebacterium glutamicum strains which produce L-amino acids. SUMMARY OF THE INVENTION [0006] L-Amino acids are used in human medicine and in the pharmaceuticals industry, in the foodstuffs industry and especially in animal nutrition. There is therefore a general interest in providing improved processes for their preparation. [0007] In general, the present invention is directed to improved processes for the fermentative preparation of L-amino acids by coryneform bacteria. More specifically, the invention provides a process for the fermentative preparation of L-amino acids (particularly L-lysine, L-threonine, L-isoleucine and L-tryptophan) using coryneform bacteria in which the nucleotide sequence which codes for the enzyme 6-phosphogluconate dehydrogenase (EC number 1.1.1.44) (gnd gene) is amplified, in particular over-expressed. BRIEF DESCRIPTION OF THE FIGURES [0008] Embodiments of the present invention will be described with reference to the following Figures, in which: [0009] [0009]FIG. 1 is a map of the plasmid pEC-T18mob2; [0010] [0010]FIG. 2 is a map of the plasmid pECgnd; [0011] [0011]FIG. 3 is a map of the plasmid pBGNA; and [0012] [0012]FIG. 4 is a map of the plasmid pCR2.1poxBint. DETAILED DESCRIPTION OF THE INVENTION [0013] The strains of bacteria employed in the present processes preferably already produce L-amino acids before amplification of the gnd gene. The term `“amplification” as used herein describes the increase in the intracellular activity of one or more enzymes or proteins in a microorganism which are encoded by the corresponding DNA. This may be accomplished, for example, by increasing the number of copies of the gene or genes, using a potent promoter or using a gene which codes for a corresponding enzyme having a high activity, or by combining these measures. [0014] By amplification measures, in particular over-expression, the activity or concentration of the corresponding enzyme or protein is in general increased by at least 10%, 25%, 50%, 75%, 100%, 150%, 200%, 300%, 400% or 500%, up to a maximum of 1000% or 2000%, compared to that of the wild-type enzyme or the activity or concentration of the enzyme in the starting microorganism. [0015] The microorganisms which the present invention provide can prepare L-amino acids from glucose, sucrose, lactose, fructose, maltose, molasses, starch, cellulose or from glycerol and ethanol. They are representatives of coryneform bacteria, in particular of the genus Corynebacterium. Of the genus Corynebacterium, the most preferred species is Corynebacterium glutamicum , which is known among experts for its ability to produce L-amino acids. Suitable strains include the wild-type strains: [0016] [0016] Corynebacterium glutamicum ATCC13032; [0017] [0017] Corynebacterium acetoglutamicum ATCC 15806; [0018] [0018] Corynebacterium acetoacidophilum ATCC13870; [0019] [0019] Corynebacterium thermoaminogenes FERM BP-1539; [0020] [0020] Brevibacterium flavum ATCC14067; [0021] [0021] Brevibacterium lactofermentum ATCC13869; [0022] Brevibacterium divaricatum ATCC14020; [0023] L-amino acid-producing mutants prepared from the strains above may also be used. Such strains include: the L-threonine-producing strains: [0024] [0024] Corynebacterium glutamicum ATCC21649; [0025] [0025] Brevibacterium flavum BB69; [0026] [0026] Brevibacterium flavum DSM5399; [0027] [0027] Brevibacterium lactofermentum FERM-BP 269; [0028] [0028] Brevibacterium lactofermentum TBB- 10; ` [0029] the L-isoleucine-producing strains: [0030] [0030] Corynebacterium glutamicum ATCC 14309; [0031] [0031] Corynebacterium glutamicum ATCC 14310; [0032] [0032] Corynebacterium glutamicum ATCC 14311; [0033] [0033] Corynebacterium glutamicum ATCC 15168; [0034] [0034] Corynebacterium ammoniagenes ATCC 6871; [0035] the L-tryptophan-producing strains: [0036] [0036] Corynebacterium glutamicum ATCC21850; [0037] [0037] Corynebacterium glutamicum KY9218(pKW9901); [0038] and the L-lysine-producing strains: [0039] [0039] Corynebacterium glutamicum FERM-P 1709; [0040] [0040] Brevibacterium flavum FERM-P 1708; [0041] [0041] Brevibacterium lactofermentum FERM-P 1712; [0042] [0042] Corynebacterium glutamicum FERM-P 6463; [0043] [0043] Corynebacterium glutamicum FERM-P 6464; [0044] [0044] Corynebacterium glutamicum DSM5715; [0045] [0045] Corynebacterium glutamicum DM58-1; and [0046] [0046] Corynebacterium glutamicum DSM12866. [0047] It has been found that coryneform bacteria produce L-amino acids, in particular L-lysine, L-threonine, L-isoleucine and L-tryptophan, in an improved manner after over-expression of the gnd gene. The gnd gene codes for the enzyme 6-phosphogluconate dehydrogenase (EC number 1.1.1.44) which catalyses the oxidative decarboxylation of 6-phosphogluconic acid to ribulose 5-phosphate. The nucleotide sequence of the gnd gene is disclosed in JP-A-9-224662. Alleles of the gnd gene which result from the degeneracy of the genetic code or which are due to sense mutations of neutral function can furthermore be used. Genes encoding proteins with 6-phosphogluconate dehydrogenase activity from Gram-negative bacteria, e.g. Escherichia coli , or other Gram-positive bacteria, e.g., Streptomyces or Bacillus, may optionally be used. [0048] The use of endogenous, genes in particular endogenous genes from `coryneform bacteria, is preferred. The terms “endogenous genes” or “endogenous nucleotide sequences” refer to genes or nucleotide sequences which are available in the population of a species. [0049] To achieve an amplification (e.g., over-expression) of a protein, the number of copies of the corresponding gene is increased, or the promoter and regulation region or the ribosome binding site upstream of the structural gene are mutated. Expression cassettes which are incorporated upstream of the structural gene act in the same way. Using inducible promoters, it is additionally possible to increase the expression in the course of fermentative L-amino acid formation. Expression may also be improved by measures to prolong the life of the m-RNA. Enzyme activity may be increased by preventing the degradation of the enzyme protein. [0050] Genes or gene constructs may either be provided in plasmids with a varying number of copies, or may be integrated and amplified in the chromosome. Alternatively, an over-expression of the genes in question can be achieved by changing the composition of the media and the culture procedure. Instructions in this context can be found by the expert, inter alia, in Martin et al. (Bio/Technology 5, 137-146 (1987)), in Guerrero et al. (Gene 138, 35-41 (1994)), Tsuchiya and Morinaga (Bio/Technology 6, 428-430 (1988)), in Eikmanns et al. (Gene 102, 93-98 (1991)), in European Patent Specification EPS 0 472 869, in U.S. Pat. No. 4,601,893, in Schwarzer and Pühler (Bio/Technology 9, 84-87 (1991), in Reinscheid et al. (Applied and Environmental Microbiology 60, 126-132 (1994)), in LaBarre et al. (Journal of Bacteriology 175, 1001-1007 (1993)), in Patent Application WO 96/15246, in Malumbres et al. (Gene 134, 15-24 (1993)), in Japanese Laid-Open Specification JP-A-10-229891, in Jensen and Hammer (Biotechnology and Bioengineering 58, 191-195 (1998)) and in known textbooks of genetics and molecular biology. [0051] By way of example, 6-phosphogluconate dehydrogenase was over-expressed with the aid of a plasmid. The E. coli - C. glutamicum shuttle vector pEC-T18mob2 shown in FIG. 1 was used for this. After incorporation of the gnd gene into the EcoRI cleavage site of pEC-T18mob2, the plasmid pECgnd shown in FIG. 2 was `formed. Other plasmid vectors which are capable of replication in C. glutamicum , such as pEKEx1 (Eikmanns et al., Gene 102:93-98 (1991)) or pZ8-1 (EP-B-0 375 889), can be used in the same way. [0052] In addition, it may be advantageous for the production of L-amino acids to amplify one or more enzymes of the relevant biosynthesis pathway, of glycolysis, of anaplerosis, of the pentose phosphate pathway or of amino acid export, in addition to amplification of the gnd gene. For example, for the preparation of L-threonine, one or more of the following genes can be amplified (over-expressed): [0053] the hom gene which codes for homoserine dehydrogenase (Peoples et al., Molecular Microbiology 2, 63-72 (1988)) or the hom dr allele which codes for a “feed back resistant” homoserine dehydrogenase (Archer et al., Gene 107, 53-59 (1991), [0054] the gap gene which codes for glyceraldehyde 3-phosphate dehydrogenase (Eikmanns et al., Journal of Bacteriology 174: 6076-6086 (1992)), [0055] the pyc gene which codes for pyruvate carboxylase (Peters-Wendisch et al., Microbiology 144: 915-927 (1998)), [0056] the mqo gene which codes for malate:quinone oxidoreductase (Molenaar et al., European Journal of Biochemistry 254, 395-403 (1998)), [0057] the tkt gene which codes for transketolase (accession number AB023377 of the databank of European Molecular Biology Laboratories (EMBL, Heidelberg, Germany)), [0058] the zwf gene which codes for glucose 6-phosphate dehydrogenase (JP-A-09224661), [0059] the thrE gene which codes for threonine export (DE 199 41 478.5; DSM 12840), [0060] the zwa1 gene (DE 199 59 328.0; DSM 13115), [0061] the eno gene which codes for enolase (DE: 199 41 478.5). [0062] For the preparation of L-lysine, one or more of the following genes can be amplified, in particular over-expressed, at the same time as gnd. [0063] the dapA gene which codes for dihydrodipicolinate synthase (EP-B 0 197 335), [0064] a lysC gene which codes for a feed back resistant aspartate kinase (Kalinowski et al. (1990), Molecular and General Genetics 224: 317-324), [0065] the gap gene which codes for glyceraldehyde 3-phosphate dehydrogenase (Eikmanns `(1992), Journal of Bacteriology 174:6076-6086), [0066] the pyc gene which codes for pyruvate carboxylase (Eikmanns (1992), Journal of Bacteriology 174:6076-6086), [0067] the mqo gene which codes for malate-quinone oxidoreductase (Molenaar et al., European Journal of Biochemistry 254, 395-403 (1998)), [0068] the tkt gene which codes for transketolase (accession number AB023377 of the databank of European Molecular Biologies Laboratories (EMBL, Heidelberg, Germany)), [0069] the zwf gene which codes for glucose 6-phosphate dehydrogenase (JP-A-09224661), [0070] the lysE gene which codes for lysine export [0071]  (DE-A-195 48 222), [0072] the zwa1 gene (DE 199 59 328.0; DSM 13115), [0073] the eno gene which codes for enolase (DE 199 47 791.4). [0074] The use of endogenous genes is preferred. [0075] It may furthermore be advantageous for the production of L-amino acids to attenuate one or more of the following genes while at the same time amplifying gnd: [0076] the pck gene which codes for phosphoenol pyruvate carboxykinase (DE 199 50 409.1; DSM 13047), [0077] the pgi gene which codes for glucose 6-phosphate isomerase (U.S. Ser. No. 09/396,478, DSM 12969), [0078] the poxB gene which codes for pyruvate oxidase [0079]  (DE 199 51 975.7; DSM 13114), [0080] the zwa2 gene (DE: 199 59 327.2; DSM 13113). [0081] In this connection, the term “attenuation” means reducing or suppressing the intracellular activity or concentration of one or more enzymes or proteins in a microorganism. This may be accomplished using the genes which encode the proteins, for example by using a weak promoter or a gene or allele which codes for a corresponding protein which has a low activity or inactivates the corresponding enzyme and optionally by combining these measures. By attenuation measures, the activity or concentration of the corresponding enzyme or protein is in general reduced to 0 to 75%, `0 to 50%, 0 to 25%, 0 to 10% or 0 to 5% of the activity or concentration of the wild-type enzyme or of the activity or concentration of the enzyme in the starting microorganism. [0082] In addition to over-expression of 6-phosphogluconate dehydrogenase, it may furthermore be advantageous for the production of L-amino acids to eliminate undesirable side reactions (see, Nakayama: “Breeding of Amino Acid Producing Microorganisms,” in: Overproduction of Microbial Products, Krumphanzl, Sikyta, Vanek (eds.), Academic Press, London, UK, 1982). [0083] The microorganisms prepared according to the invention can be cultured continuously or discontinuously in a batch process (batch culture) or in a fed batch (feed process) or repeated fed batch process (repetitive feed process) for the purpose of L-amino acid production. A summary of known culture methods is described in the textbook by Chmiel (Bioprozesstechnik 1. Einführung in die Bioverfahrenstechnik [Bioprocess Technology 1. Introduction to Bioprocess Technology (Gustav Fischer Verlag, Stuttgart, 1991)) or in the textbook by Storhas (Bioreaktoren und periphere Einrichtungen [Bioreactors and Peripheral Equipment] (Vieweg Verlag, Braunschweig/Wiesbaden, 1994)). The culture medium to be used must meet the requirements of the particular microorganisms in a suitable manner. Descriptions of culture media for various microorganisms are contained in the handbook “Manual of Methods for General Bacteriology” of the American Society for Bacteriology (Washington D.C., USA, 1981). Sugars and carbohydrates, such as e.g. glucose, sucrose, lactose, fructose, maltose, molasses, starch and cellulose, oils and fats, such as e.g. soya oil, sunflower oil, groundnut oil and coconut fat, fatty acids, such as e.g. palmitic acid, stearic acid and linoleic acid, alcohols, such as e.g. glycerol and ethanol, and organic acids, such as e.g. acetic acid, can be used as the source of carbon. These substances can be used individually or as a mixture. Organic nitrogen-containing compounds, such as peptones, yeast extract, meat extract, malt extract, corn steep liquor, soya bean flour and urea, or inorganic compounds, such as ammonium sulfate, ammonium chloride, ammonium phosphate, ammonium carbonate and ammonium nitrate, can be used as the source of nitrogen. The sources of nitrogen can be used individually or as a mixture. Potassium dihydrogen phosphate or dipotassium hydrogen `phosphate or the corresponding sodium-containing salts can be used as the source of phosphorus. The culture medium must furthermore comprise salts of metals, such as e.g. magnesium sulfate or iron sulfate, which are necessary for growth. Finally, essential growth substances, such as amino acids and vitamins, can be employed in addition to the above-mentioned substances. Suitable precursors can moreover be added to the culture medium. The starting substances mentioned can be added to the culture in the form of a single batch, or can be fed in during the culture in a suitable manner. [0084] Basic compounds, such as sodium hydroxide, potassium hydroxide, ammonia, or acid compounds, such as phosphoric acid or sulfuric acid, can be employed in a suitable manner to control the pH. Antifoams, such as fatty acid polyglycol esters, can be employed to control the development of foam. Suitable substances having a selective action, e.g. antibiotics, can be added to the medium to maintain the stability of plasmids. To maintain aerobic conditions, oxygen or oxygen-containing gas mixtures, such as e.g. air, are introduced into the culture. The temperature of the culture is usually 20° C. to 45° C., and preferably 25° C. to 40° C. Culturing is continued until a maximum of L-amino acid has formed. This target is usually reached within 10 hours to 160 hours. [0085] The analysis of L-amino acids can be carried out by anion exchange chromatography with subsequent ninhydrin derivation, as described by Spackman et al. (Analytical Chemistry, 30, (1958), 1190), or it can take place by reversed phase HPLC as described by Lindroth et al. (Analytical Chemistry (1979) 51:. 1167-1174). [0086] The following microorganism has been deposited at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) in accordance with the Budapest Treaty: Escherichia coli K-12 DH5α/pEC-T18mob2 as DSM 13244. [0087] In the accompanying Figures, the base pair numbers stated are approx. values obtained in the context of reproducibility. The abbreviations used in the Figures have the following meaning: ` In FIG. 1: Tet: Resistance gene for tetracycline oriV: Plasmid-coded replication origin of E. coli RP4mob: mob region for mobilizing the plasmid rep: Plasmid-coded replication origin from C. glutamicum plasmid pGA1 per: Gene for controlling the number of copies from pGA1 lacZ-alpha: lacZα gene fragment (N-terminus) of the β-Galactosidase gene. In FIG. 2: Tet: Resistance gene for tetracycline rep: Plasmid-coded replication origin from C. glutamicum plasmid pGA1 per: Gene for controlling the number of copies from PGA1 lacZ Cloning relict of the lacZα gene fragment from pEC-T18mob2 gnd: 6-Phosphogluconate dehydrogenase gene. In FIG. 3: LacP: Promoter of the E. coli lactose operon CMV: Promoter of cytomegalovirus ColE1: Replication origin of the plasmid ColE1 TkpolyA: Polyadenylation site Kan r: Kanamycin resistance gene SV40ori: Replication origin of Simian virus 40 gnd: 6-Phosphogluconate dehydrogenase gene. In FIG. 4: ColE1 ori: Replication origin of the plasmid ColE1 lacZ: Cloning relict of the lacZα gene fragment fl ori: Replication origin of phage f1 KmR: Kanamycin resistance ApR: Ampicillin resistance poxBint: internal fragment of the poxB gene [0088] The following abbreviations have also been used herein: AccI: Cleavage site of the restriction enzyme AccI BamHI: Cleavage site of the restriction enzyme BamHI EcoRI: Cleavage site of the restriction enzyme EcoRI HindIII: Cleavage site of the restriction enzyme HindIII KpnI: Cleavage site of the restriction enzyme KpnI PstI: Cleavage site of the restriction enzyme PstI PvuI: Cleavage site of the restriction enzyme PvuI SalI: Cleavage site of the restriction enzyme SalI SacI: Cleavage site of the restriction enzyme SacI SmaI: Cleavage site of the restriction enzyme SmaI SphI: Cleavage site of the restriction enzyme SphI XbaI: Cleavage site of the restriction enzyme XbaI XhoI: Cleavage site of the restriction enzyme XhoI [0089] The following examples will further illustrate this invention. The molecular biology techniques, e.g. plasmid DNA isolation, restriction enzyme treatment, ligations, standard transformations of Escherichia coli etc. used are, (unless stated otherwise), are described by Sambrook et al., (Molecular Cloning. A Laboratory Manual (1989) Cold Spring Harbor Laboratories, USA). EXAMPLE 1 Construction of a Gene Library of Corynebacterium glutamicum Strain AS019 [0090] A DNA library of Corynebacterium glutamicum strain AS019 (Yoshihama et al., Journal of Bacteriology 162, 591-597 (1985)) was constructed using λ Zap Express™ system, (Short et al., (1988) Nucleic Acids Research 16: 7583-7600), as described by O'Donohue (O'Donohue, M. (1997). The Cloning and Molecular Analysis of Four Common Aromatic Amino Acid Biosynthetic Genes from Corynebacterium glutamicum. Ph.D. Thesis, National University of Ireland, Galway). λ Zap Express™ kit was purchased from Stratagene (Stratagene, 11011 North Torrey Pines Rd., La Jolla, Calif. 92037) and used according to the manufacturer's instructions. AS019-DNA was digested with restriction enzyme Sau3A and ligated to `BamHI treated and dephosphorylated λ Zap Express™ arms. EXAMPLE 2 Cloning and Sequencing of the gnd Gene [0091] 2.1 Construction of a gnd Probe [0092] A radio-labeled oligonucleotide, internal to the gnd gene, was used to probe the AS019 λ Zap Express™ library described above. The oligonucleotide was produced using degenerate PCR primers internal to the gnd gene. The degenerate nucleotide primers designed for the PCR amplification of gnd DNA fragments were as follows: [0093] gnd1: 5′ ATG GTK CAC ACY GGY ATY GAR TA 3′ (SEQ ID NO 7) [0094] gnd2: 5′ RGT CCA YTT RCC RGT RCC YTT 3′ (SEQ ID NO 8) [0095] with R=A+G; Y=C+T; K=T+G. [0096] The estimated size of the resulting PCR product was 252 bp approximately. Optimal PCR conditions were determined to be as follows: [0097] 35 cycles [0098] 94° C. for 1 minute [0099] 55° C. for 1 minute [0100] 72° C. for 30 seconds [0101] 2.5-3.5 mM MgCl 2 [0102] 100-150 ng AS019 genomic DNA. [0103] Sequence analysis of the resulting PCR product confirmed the product to be an internal portion of a gnd gene. Sequence analysis was carried out using the universal forward and reverse primers, and T7 sequencing kit from Pharmacia Biotech, (St. Albans, Herts, UK). The sequence of the PCR product is shown in SEQ ID No. 1. [0104] [0104] 2 . 2 Cloning [0105] Screening of the AS019 λ Zap Express™ library was carried out according to the λ Zap Express™ system protocol, (Stratagene, 11011 North Torrey Pines Rd., La Jolla, Calif. 92037). Southern Blot analysis was then carried out on isolated clones. Southern transfer of DNA was as described in the Schleicher and Schuell protocols manual employing Nytran™ as membrane (,,Nytran, Modified Nylon `66 Membrane Filters” (March 1987), Schleicher and Schuell, Dassel, Germany). Double stranded DNA fragments, generated using the same primers and optimal PCR conditions as described above, were radio-labeled with α- 32 P-dCTP using the Multiprime™ DNA labeling kit from Amersham Life Science (Amersham Pharmacia Biotech UK Limited, Little Chalfont, Buckinghamshire, UK) according to the manufacturers instructions. Prehybridization, hybridization and washing conditions were as described in the Schleicher and Schuell protocols manual. Autoradiography was carried out according to the procedure outlined in the handbook of Sambrook et al. using AgFa Curix RPIL film. Thus several gnd clones were identified. Plasmid DNA was isolated from one of the clones, designated pBGNA (FIG. 3) and chosen for further analysis. [0106] 2.3 Sequencing [0107] The Sanger Dideoxy chain termination method of Sanger et al. (Proceedings of the National Academy of Sciences USA 74, 5463-5467 (1977)) was used to sequence the cloned insert of pBGNA. The method was applied using the T7 sequencing kit and α- 35 S-dCTP from Pharmacia Biotech (St. Albans, Herts, UK). Samples were electrophoresed for 3-8 hours on 6% polyacrylamide/urea gels in TBE buffer at a constant current of 50 mA, according to the Pharmacia cloning and sequencing instructions manual (,, T7 Sequencing™ Kit”,ref.XY-010-00-19, Pharmacia Biotech, 1994). Sequence analysis was carried out using internal primers designed from the sequence known of the internal gnd PCR product (SEQ ID NO 1) allowing the entire gnd gene sequence to be deduced. The sequences of the internal primers were as follows: Internal primer 1: 5′ GGT GGA TGC TGA AAC CG 3′ (SEQ ID NO 9) Internal primer 2: 5′ GCT GCA TGC CTG CTG CG 3′ (SEQ ID NO 10) Internal primer 3: 5′ TTG TTG CTT ACG CAC AG 3′ (SEQ ID NO 11) Internal primer 4: 5′ TCG TAG GAC TTT GCT GG 3′ (SEQ ID NO 12) [0108] Sequences obtained were analyzed using the DNA Strider program, (Marck (1988), Nucleic Acids Research 16: 1829-1836), version 1.0 on an Apple Macintosh computer. This program allowed for analyses such as restriction site usage, open reading frame analysis and codon usage determination. Searches between DNA sequences obtained and those in EMBL and Genbank databases were performed using the BLAST program (Altschul et al., (1997), Nucleic Acids Research 25: 3389-3402). DNA and protein sequences were aligned using the Clustal V and Clustal W programs (Higgins and Sharp, 1988 Gene 73: 237-244). [0109] The sequence thus obtained is shown in SEQ ID NO 2. The analysis of the nucleotide sequence obtained revealed an open reading frame of 1377 base pairs which was designated as gnd gene. It codes for a protein of 459 amino acids shown in SEQ ID NO 3. EXAMPLE 3 Preparation of the Shuttle Vector pEC-T18mob2 [0110] The E. coli - C. glutamicum shuttle vector pEC-T18mob2 was constructed according to the prior art. The vector contains the replication region, rep, of the plasmid pGA1 including the replication effector, per (U.S. Pat. No. 5,175,108; Nesvera et al., Journal of Bacteriology 179, 1525-1532 (1997)), the tetracycline resistance-imparting tetA(Z) gene of the plasmid, pAG1 (U.S. Pat. No. 5,158,891; gene library entry at the National Center for Biotechnology Information (NCBI, Bethesda, Md., USA) with accession number AF121000), the replication region, oriV, of the plasmid pMB1 (Sutcliffe, Cold Spring Harbor Symposium on Quantitative Biology 43, 77-90 (1979)), the lacZ gene fragment including the lac promoter and a multiple cloning site (mcs) (Norrander et al. Gene 26, 101-106 (1983)) and the mob region of the plasmid RP4 (Simon et al.,(1983) Bio/Technology 1:784-791). [0111] The vector constructed was transformed in the E. coli strain DH5α (Hanahan, In: DNA cloning. A practical approach. Vol. I. IRL-Press, Oxford, Washington D.C., USA, 1985). Selection for plasmid-carrying cells was made by plating out the transformation batch on LB agar (Sambrook et al., Molecular cloning: a laboratory manual. 2 nd Ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., USA, 1989), which had been supplemented with 5 mg/l tetracycline. Plasmid DNA was isolated from a transformant with the aid of the QIAprep Spin Miniprep Kit from Qiagen and checked by restriction with the restriction enzyme EcoRI and HindIII subsequent agarose gel electrophoresis (0.8%). The plasmid was called pEC-T18mob2 and is shown in FIG. 1. It is deposited in the form of the strain Escherichia coli K-12 strain DH5α/pEC-T18mob2 at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) as DSM 13244. EXAMPLE 4 Cloning of the gnd Gene into the E. coli - C. glutamicum Shuttle Vector pEC-T18mob2 [0112] PCR was used to amplify DNA fragments containing the entire gnd gene of C. glutamicum and flanking upstream and downstream regions using pBGNA as template. PCR reactions were carried out using oligonucleotide primers designed from SEQ ID NO 2. The primers used were: gnd fwd. primer: 5′ ACT CTA GTC GGC CTA AAA TGG 3′ (SEQ ID NO 13) gnd rev. primer: 5′ CAC ACA GGA AAC AGA TAT GAC 3′. (SEQ ID NO 14) [0113] PCR parameters were as follows: [0114] 35 cycles [0115] 95° C. for 6 minutes [0116] 94° C. for 1 minute [0117] 50° C. for 1 minute [0118] 72° C. for 45 seconds [0119] 1 mM MgCl 2 [0120] approx. 150-200 ng pBGNA-DNA as template. [0121] The PCR product obtained was cloned into the commercially available pGEM-T vector purchased from Promega Corp. (pGEM-T Easy Vector System 1, cat. no. A1360, Promega UK, Southampton) using E. coli strain JM109 (Yanisch-Perron et al. Gene, 33: 103-119 (1985)) as a host. The entire gnd gene was subsequently isolated from the pGEM T-vector on an EcoRI fragment and cloned into the lacZ EcoRI site of the E. coli - C. glutamicum shuttle vector pEC-T18mob2 (FIG. 1), and designated pECgnd (FIG. 2). Restriction enzyme analysis with AccI (Boehringer Mannheim GmbH, Germany) revealed the correct orientation (i.e., downstream the lac-Promotor) of the gnd gene in the lacZα gene of pEC-T18mob2. EXAMPLE 5 Preparation of Amino Acid Producers with Amplified 6-phosphogluconate Dehydrogenase [0122] Plasmid pECgnd from Example 3 was electroporated by the electroporation method of Tauch et al. (FEMS Microbiological Letters, 123:343-347 (1994)) in the strains Corynebacterium glutamicum DSM 5399 and DSM 5714. The strain DSM 5399 is a threonine producer described in EP-B-0358940. The strain DSM 5714 is a lysine producer described in EP-B-0435132. Selection of transformants was carried out by plating out the electroporation batch on LB agar (Sambrook et al., Molecular cloning: a laboratory manual. 2 nd Ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989), which had been supplemented with 25 mg/l kanamycin. The strains DSM5399/pECgnd and DSM5714/pECgnd were formed in this manner. EXAMPLE 6 Preparation of Threonine [0123] The C. glutamicum strain DSM5399/pECgnd obtained in Example 5 was cultured in a nutrient medium suitable for the production of threonine and the threonine content in the culture supernatant was determined. For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l)) for 24 hours at 33° C. Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask). Brain-heart broth (Merck, Darmstadt, Germany) was used as the medium for the preculture. Tetracycline (5 mg/l) was added to this medium. The preculture was incubated for 24 hours at 33° C. at 240 rpm on a shaking machine. A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.1. The medium MM-threonine was used for the main culture. Medium MM-threonine CSL 5 g/l MOPS 20 g/l Glucose(autoclaved separately) 50 g/l Salts: (NH 4 ) 2 SO 4 25 g/l KH 2 PO 4 0.1 g/l MgSO 4 * 7 H 2 O 1.0 g/l CaCl 2 * 2 H 2 O 10 mg/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 5.0 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l CaCO 3 25 g/l [0124] The CSL (corn steep liquor), MOPS (morpholinopropanesulfonic acid) and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved. The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state. Culturing is carried out in a 10 ml volume in a 100 ml conical flask with baffles. Tetracycline (5 mg/l) was added. Culturing was carried out at 33° C. and 80% atmospheric humidity. After 48 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, Munich). The concentration of threonine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivation with ninhydrin detection. The result of the experiment is shown in Table 1. TABLE 1 OD L-Threonin Strain (660 nm) g/l DSM5399/pECgnd 11.9 1.29 DSM5399 11.8 0.33 EXAMPLE 7 Preparation of Lysine [0125] The C. glutamicum strain DSM5714/pECgnd obtained in Example 5 was cultured in a nutrient medium suitable for the production of lysine and the lysine content in the culture supernatant was determined. For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l)) for 24 hours at 33° C. Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask). The complete medium Cg III was used as the medium for the preculture. Medium Cg III NaCl 2.5 g/l Bacto-Peptone 10 g/l Bacto-Yeast extract 10 g/l Glucose (autoclaved separately) 2% (w/v) [0126] Tetracycline (5 mg/l) was added to this medium. The preculture was incubated for 24 hours at 33° C. at 240 rpm on a shaking machine. A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.05. Medium MM was used for the main culture. Medium MM CSL (corn steep liquor) 5 g/l MOPS (morpholinopropanesulfonic acid) 20 g/l Glucose (autoclaved separately) 50 g/l (NH 4 ) 2 SO 4 KH 2 PO 4 25 g/l MgSO 4 * 7 H 2 O 0.1 g/l CaCl 2 * 2 H 2 O 1.0 g/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 10 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l L-Leucine (sterile-filtered) 0.1 g/l CaCO 3 25 g/l [0127] The CSL, MOPS and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved. The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state. Culturing was carried out in a 10 ml volume in a 100 ml conical flask with baffles. Tetracycline (5 mg/l) was added. Culturing was carried out at 33° C. and 80% atmospheric humidity. [0128] After 48 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, München). The amount of lysine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivation with ninhydrin detection. The result of the experiment is shown in Table 2. TABLE 2 OD Lysine HCl Strain (660 nm) g/l DSM5715/pECgnd 7.7 14.7 DSM5715 7.1 13.7 EXAMPLE 8 Preparation of a Genomic Cosmid Gene Library from Corynebacterium glutamicum ATCC 13032 [0129] Chromosomal DNA from Corynebacterium glutamicum ATCC 13032 was isolated as described by Tauch et al., (1995, Plasmid 33:168-179), and partly cleaved with the restriction enzyme Sau3AI (Amersham Pharmacia, Freiburg, Germany, Product Description Sau3AI, Code no. 27-0913-O 2 ). The DNA fragments were dephosphorylated with shrimp alkaline phosphatase (Roche Molecular Biochemicals, Mannheim, Germany, Product Description SAP, Code no. 1758250). The DNA of the cosmid vector SuperCos1 (Wahl et al. (1987) Proceedings of the National Academy of Sciences USA 84:2160-2164), obtained from Stratagene (La Jolla, USA, Product Description SuperCos1 Cosmid Vektor Kit, Code no. 251301) was cleaved with the restriction enzyme XbaI (Amersham Pharmacia, Freiburg, Germany, Product Description XbaI, Code no. 27-0948-O 2 ) and likewise dephosphorylated with shrimp alkaline phosphatase. [0130] The cosmid DNA was then cleaved with the restriction enzyme BamHI (Amersham Pharmacia, Freiburg, Germany, Product Description BamHI, Code no. 27-0868-04). The cosmid DNA treated in this manner was mixed with the treated ATCC13032 DNA and the batch was treated with T4 DNA ligase (Amersham Pharmacia, Freiburg, Germany, Product Description T4-DNA-Ligase, Code no.27-0870-04). The ligation mixture was then packed in phages with the aid of Gigapack II XL Packing Extracts (Stratagene, La Jolla, USA, Product Description Gigapack II XL Packing Extract, Code no. 200217). For infection of the E. coli strain NM554 (Raleigh et al. 1988, Nucleic Acid Research 16:1563-1575) the cells were taken up in 10 mM MgSO 4 and mixed with an aliquot of the phage suspension. The infection and titering of the cosmid library were carried out as described by Sambrook et al. (1989, Molecular Cloning: A laboratory Manual, Cold Spring Harbor), the cells being plated out on LB agar (Lennox, 1955, Virology 1:190)+100 μg/ml ampicillin. After incubation overnight at 37° C., recombinant individual clones were selected. EXAMPLE 9 Isolation and Sequencing of the poxB Gene [0131] The cosmid DNA of an individual colony (Example 8) was isolated with the Qiaprep Spin Miniprep Kit (Product No. 27106, Qiagen, Hilden, Germany) in accordance with the manufacturer's instructions and partly cleaved with the restriction enzyme Sau3AI (Amersham Pharmacia, Freiburg, Germany, Product Description Sau3AI, Product No. 27-0913-O 2 ). The DNA fragments were dephosphorylated with shrimp alkaline phosphatase (Roche Molecular Biochemicals, Mannheim, Germany, Product Description SAP, Product No. 1758250). After separation by gel electrophoresis, the cosmid fragments in the size range of 1500 to 2000 bp were isolated with the QiaExII Gel Extraction Kit (Product No. 20021, Qiagen, Hilden, Germany). The DNA of the sequencing vector pZero-1, obtained from Invitrogen (Groningen, Holland, Product Description Zero Background Cloning Kit, Product No. K2500-01) was cleaved with the restriction enzyme BamHI (Amersham Pharmacia, Freiburg, Germany, Product Description BamHI, Product No. 27-0868-04). [0132] The ligation of the cosmid fragments in the sequencing vector pZero-1 was carried out as described by Sambrook et al. (1989, Molecular Cloning: A laboratory Manual, Cold Spring Harbor), the DNA mixture being incubated overnight with T4 ligase (Pharmacia Biotech, Freiburg, Germany). This ligation mixture was then electroporated (Tauch et al. 1994, FEMS Microbiol Letters, 123:343-7) into the E. coli strain DH5αMCR (Grant, 1990, Proceedings of the National Academy of Sciences U.S.A., 87:4645-4649) and plated out on LB agar (Lennox, 1955, Virology, 1:190) with 50 μg/ml zeocin. The plasmid preparation of the recombinant clones was carried out with Biorobot 9600 (Product No. 900200, Qiagen, Hilden, Germany). The sequencing was carried out by the dideoxy chain-stopping method of Sanger et al. (1977, Proceedings of the National Academies of Sciences U.S.A., 74:5463-5467) with modifications according to Zimmermann et al. (1990, Nucleic Acids Research, 18:1067). The “RR dRhodamin Terminator Cycle Sequencing Kit” from PE Applied Biosystems(Product No. 403044, Weiterstadt, Germany) was used. The separation by gel electrophoresis and analysis of the sequencing reaction were carried out in a “Rotiphoresis NF Acrylamide/Bisacrylamide” Gel (29:1) (Product No. A124.1, Roth, Karlsruhe, Germany) with the “ABI Prism 377” sequencer from PE Applied Biosystems (Weiterstadt, Germany). [0133] The raw sequence data obtained were then processed using the Staden program package (1986, Nucleic Acids Research, 14:217-231) version 97-0. The individual sequences of the pZero1 derivatives were assembled to a continuous contig. The computer-assisted coding region analysis were prepared with the XNIP program (Staden, 1986, Nucleic Acids Research 14:217-231). Further analyses were carried out with the “BLAST search program” (Altschul et al., 1997, Nucleic Acids Research 25:3389-3402), against the non-redundant databank of the “National Center for Biotechnology Information” (NCBI, Bethesda, Md., USA). [0134] The resulting nucleotide sequence is shown in SEQ ID No. 4. Analysis of the nucleotide sequence showed an open reading frame of 1737 base pairs, which was called the poxB gene. The poxB gene codes for a polypeptide of 579 amino acids (SEQ ID NO. 5). EXAMPLE 10 Preparation of an Integration Vector for Integration Mutagenesis of the poxB Gene [0135] From the strain ATCC 13032, chromosomal DNA was isolated by the method of Eikmanns et al. (Microbiology 140: 1817-1828 (1994)). On the basis of the sequence of the poxB gene known for C. glutamicum from Example 9, the following oligonucleotides were chosen for the polymerase chain reaction: poxBint1: 5′ TGC GAG ATG GTG AAT GGT GG 3′ (SEQ ID NO 15) poxBint2: 5′ GCA TGA GGC AAC GCA TTA GC 3′ (SEQ ID NO 16) [0136] The primers shown were synthesized by MWG Biotech (Ebersberg, Germany) and the PCR reaction was carried out by the standard PCR method of Innis et al. (PCR protocols. A guide to methods and applications, 1990, Academic Press) with Pwo-Polymerase from Boehringer. With the aid of the polymerase chain reaction, a DNA fragment approx. 0.9 kb in size was isolated, this carrying an internal fragment of the poxB gene and being shown in SEQ ID No:6. [0137] The amplified DNA fragment was ligated with the TOPO TA Cloning Kit from Invitrogen Corporation (Carlsbad, Calif., USA; Catalogue Number K4500-01) in the vector pCR2.1-TOPO (Mead at al. (1991) Bio/Technology 9:657-663). The E. coli Stamm DH5α was then electroporated with the ligation batch (Hanahan, In: DNA cloning. A practical approach. Vol. 1. IRL-Press, Oxford, Washington D.C., USA, 1985). Selection for plasmid-carrying cells was made by plating out the transformation batch on LB agar (Sambrook et al., Molecular cloning: a laboratory manual. 2 nd Ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989), which had been supplemented with 25 mg/l kanamycin. Plasmid DNA was isolated from a transformant with the aid of the QIAprep Spin Miniprep Kit from Qiagen and checked by restriction with the restriction enzyme EcoRI and subsequent agarose gel electrophoresis (0.8%). The plasmid was called pCR2.1poxBint (FIG. 4). [0138] Plasmid pCR2.1poxBint has been deposited in the form of the strain Escherichia coli DH5α/pCR2.1poxBint as DSM 13114 at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) in accordance with the Budapest Treaty. EXAMPLE 11 Integration Mutagenesis of the poxB Gene in the Lysine Producer DSM 5715 [0139] The vector pCR2.1poxBint mentioned in Example 10 was electroporated by the electroporation method of Tauch et al.(FEMS Microbiological Letters, 123:343-347 (1994)) in Corynebacterium glutamicum DSM 5715. Strain DSM 5715 is an AEC-resistant lysine producer. The vector pCR2.1poxBint cannot replicate independently in DSM5715 and is retained only if it has integrated into the cell's chromosome. Selection of clones with pCR2.1poxBint integrated into the chromosome was carried out by plating out the electroporation batch on LB agar (Sambrook et al., Molecular Cloning: A Laboratory Manual. 2 nd ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.), which had been supplemented with 15 mg/l kanamycin. For detection of the integration, the poxBint fragment was labeled with the Dig hybridization kit from Boehringer by the method of “The DIG System Users Guide for Filter Hybridization” of Boehringer Mannheim GmbH (Mannheim, Germany, 1993). Chromosomal DNA of a potential integrant was isolated by the method of Eikmanns et al. (Microbiology 140: 1817-1828 (1994)) and in each case cleaved with the restriction enzymes SalI, SacI and HindIII. The fragments formed were separated by agarose gel electrophoresis and hybridized at 68° C. with the Dig hybridization kit from Boehringer. The plasmid pCR2.1poxBint mentioned in Example 9 had been inserted into the chromosome of DSM5715 within the chromosomal poxB gene. The strain was called DSM5715::pCR2.1poxBint. EXAMPLE 12 Effect of Over-Expression of the gnd Gene with Simultaneous Elimination of the poxB Gene on the Preparation of Lysine [0140] 12.1 Preparation of the Strain DSM5715::pCR2.1poxBint/pECgnd [0141] The strain DSM5715::pCR2.1poxBint was transformed with the plasmid pECgnd using the electroporation method described by Liebl et al., (FEMS Microbiology Letters, 53:299-303 (1989)). Selection of the transformants took place on LBHIS agar comprising 18.5 μl brain-heart infusion broth, 0.5 M sorbitol, 5 g/l Bacto-tryptone, 2.5 g/l Bacto-yeast extract, 5 g/l NaCl and 18 g/l Bacto-agar, which had been supplemented with 5 mg/l tetracycline and 25 mg/l kanamycin. Incubation was carried out for 2 days at 33° C. [0142] Plasmid DNA was isolated in each case from a transformant by conventional methods (Peters-Wendisch et al., 1998, Microbiology 144, 915-927), cleaved with the restriction endonuclease AccI, and the plasmid was checked by subsequent agarose gel electrophoresis. The strain obtained in this way was called DSM5715:pCR2.1poxBint/pECgnd. [0143] 12.2 Preparation of L-lysine [0144] The C. glutamicum strain DSM5715::pCR2.1poxBint/pECgnd obtained in Example 12.1 was cultured in a nutrient medium suitable for the production of lysine and the lysine content in the culture supernatant was determined. For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l) and kanamycin (25 mg/l)) for 24 hours at 33° C. The cultures of the comparison strains were supplemented according to their resistance to antibiotics. Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask). The complete medium CgIII was used as the medium for the preculture. Medium Cg III NaCl 2.5 g/l Bacto-Peptone 10 g/l Bacto-Yeast extract 10 g/l Glucose (autoclaved separately) 2% (w/v) [0145] Tetracycline (5 mg/l) and kanamycin (25 mg/l) were added to this. The preculture was incubated for 16 hours at 33° C. at 240 rpm on a shaking machine. A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.1. Medium MM was used for the main culture. Medium MM CSL (corn steep liquor) 5 g/l MOPS (morpholinopropanesulfonic acid) 20 g/l Glucose (autoclaved separately) 58 g/l (NH 4 ) 2 SO 4 25 g/l KH 2 PO 4 0.1 g/l MgSO 4 * 7 H 2 O 1.0 g/l CaCl 2 * 2 H 2 O 10 mg/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 5.0 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l L-Leucine (sterile-filtered) 0.1 g/l CaCO 3 25 g/l [0146] The CSL, MOPS and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved. The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state. Culturing was carried out in a 10 ml volume in a 100 ml conical flask with baffles. Tetracycline (5 mg/l) and kanamycin (25 mg/l) were added. Culturing was carried out at 33° C. and 80% atmospheric humidity. [0147] After 72 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, München). The amount of lysine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivatization with ninhydrin detection. The result of the experiment is shown in Table 3. TABLE 3 OD L-Lysine HCl Strain (660 nm) g/l DSM5715 10.8 16.0 DSM5715/pECgnd 7.6 16.5 DSM5715::pCR2.1poxBint 7.1 16.7 DSM5715::pCR2.1poxBint/ 7.2 17.1 pECgnd [0148] [0148] 1 16 1 252 DNA Corynebacterium glutamicum 1 atggtccaca acggcatcga gtacgccgac atgcaggtca tcggcgaggc ataccacctt 60 ctgccctacg cagcaggcat gcagccagct gaaatcgctg aggttttcaa ggaatggaac 120 gcaggcgacc tggattccta cctcatcgaa atcaccgcag aggttctctc ccaggtggat 180 gctgaaaccg gcaagccact aatcgacgtc atcgttgacg ctgcaggtca gaagggcacc 240 ggcaagtgga ct 252 2 2335 DNA Corynebacterium glutamicum CDS (474)..(1850) gnd 2 ttgttcggcc acgatgacac cggagctcac agcagaaatg aagtcggtgt tgttgttgat 60 gccgacgacc atttttccag gggcggaaat catgctggcg actgatccag tggattcggc 120 gatggcggcg tagacaccac cgttgaccaa gcccaccact tgcaggtgct tggatgccac 180 gtgaagttcg ctgaccaccc ggccgggctc gatggtggtg tagcgcagcc ccagattgcg 240 gtcgaggcca taattggcgt tgttgagtgc ttcaagttcg tctgtggtta aagctctggt 300 ggcggcaagt tctgcaagcg aaagcagatc ttggggttga tcatcgcggg aagtcataat 360 taattactct agtcggccta aaatggttgg attttcacct cctgtgacct ggtaaaatcg 420 ccactacccc caaatggtca caccttttag gccgattttg ctgacaccgg gct atg 476 Met 1 ccg tca agt acg atc aat aac atg act aat gga gat aat ctc gca cag 524 Pro Ser Ser Thr Ile Asn Asn Met Thr Asn Gly Asp Asn Leu Ala Gln 5 10 15 atc ggc gtt gta ggc cta gca gta atg ggc tca aac ctc gcc cgc aac 572 Ile Gly Val Val Gly Leu Ala Val Met Gly Ser Asn Leu Ala Arg Asn 20 25 30 ttc gcc cgc aac ggc aac act gtc gct gtc tac aac cgc agc act gac 620 Phe Ala Arg Asn Gly Asn Thr Val Ala Val Tyr Asn Arg Ser Thr Asp 35 40 45 aaa acc gac aag ctc atc gcc gat cac ggc tcc gaa ggc aac ttc atc 668 Lys Thr Asp Lys Leu Ile Ala Asp His Gly Ser Glu Gly Asn Phe Ile 50 55 60 65 cct tct gca acc gtc gaa gag ttc gta gca tcc ctg gaa aag cca cgc 716 Pro Ser Ala Thr Val Glu Glu Phe Val Ala Ser Leu Glu Lys Pro Arg 70 75 80 cgc gcc atc atc atg gtt cag gct ggt aac gcc acc gac gca gtc atc 764 Arg Ala Ile Ile Met Val Gln Ala Gly Asn Ala Thr Asp Ala Val Ile 85 90 95 aac cag ctg gca gat gcc atg gac gaa ggc gac atc atc atc gac ggc 812 Asn Gln Leu Ala Asp Ala Met Asp Glu Gly Asp Ile Ile Ile Asp Gly 100 105 110 ggc aac gcc ctc tac acc gac acc att cgt cgc gag aag gaa atc tcc 860 Gly Asn Ala Leu Tyr Thr Asp Thr Ile Arg Arg Glu Lys Glu Ile Ser 115 120 125 gca cgc ggt ctc cac ttc gtc ggt gct ggt atc tcc ggc ggc gaa gaa 908 Ala Arg Gly Leu His Phe Val Gly Ala Gly Ile Ser Gly Gly Glu Glu 130 135 140 145 ggc gca ctc aac ggc cca tcc atc atg cct ggt ggc cca gca aag tcc 956 Gly Ala Leu Asn Gly Pro Ser Ile Met Pro Gly Gly Pro Ala Lys Ser 150 155 160 tac gag tcc ctc gga cca ctg ctt gag tcc atc gct gcc aac gtt gac 1004 Tyr Glu Ser Leu Gly Pro Leu Leu Glu Ser Ile Ala Ala Asn Val Asp 165 170 175 ggc acc cca tgt gtc acc cac atc ggc cca gac ggc gcc ggc cac ttc 1052 Gly Thr Pro Cys Val Thr His Ile Gly Pro Asp Gly Ala Gly His Phe 180 185 190 gtc aag atg gtc cac aac ggc atc gag tac gcc gac atg cag gtc atc 1100 Val Lys Met Val His Asn Gly Ile Glu Tyr Ala Asp Met Gln Val Ile 195 200 205 ggc gag gca tac cac ctt ctg ccc tac gca gca ggc atg cag cca gct 1148 Gly Glu Ala Tyr His Leu Leu Pro Tyr Ala Ala Gly Met Gln Pro Ala 210 215 220 225 gaa atc gct gag gtt ttc aag gaa tgg aac gca ggc gac ctg gat tcc 1196 Glu Ile Ala Glu Val Phe Lys Glu Trp Asn Ala Gly Asp Leu Asp Ser 230 235 240 tac ctc atc gaa atc acc gca gag gtt ctc tcc cag gtg gat gct gaa 1244 Tyr Leu Ile Glu Ile Thr Ala Glu Val Leu Ser Gln Val Asp Ala Glu 245 250 255 acc ggc aag cca cta atc gac gtc atc gtt gac gct gca ggt cag aag 1292 Thr Gly Lys Pro Leu Ile Asp Val Ile Val Asp Ala Ala Gly Gln Lys 260 265 270 ggc acc ggc aag tgg act gtc aag gct gct ctt gat ctg ggt att gct 1340 Gly Thr Gly Lys Trp Thr Val Lys Ala Ala Leu Asp Leu Gly Ile Ala 275 280 285 acc acc ggc atc ggc gaa cgt gtt ttc gca cgt gca ctc tcc ggc gca 1388 Thr Thr Gly Ile Gly Glu Arg Val Phe Ala Arg Ala Leu Ser Gly Ala 290 295 300 305 acc agc cag cgc gct gca gca cag ggc aac cta cct gca ggt gtc ctc 1436 Thr Ser Gln Arg Ala Ala Ala Gln Gly Asn Leu Pro Ala Gly Val Leu 310 315 320 acc gat ctg gaa gca ctt ggc gtg gac aag gca cag ttc gtc gaa gga 1484 Thr Asp Leu Glu Ala Leu Gly Val Asp Lys Ala Gln Phe Val Glu Gly 325 330 335 ctt cgc cgt gca ctg tac gca tcc aag ctt gtt gct tac gca cag ggc 1532 Leu Arg Arg Ala Leu Tyr Ala Ser Lys Leu Val Ala Tyr Ala Gln Gly 340 345 350 ttc gac gag atc aag gct ggc tcc gac gag aac aac tgg gac gtt gac 1580 Phe Asp Glu Ile Lys Ala Gly Ser Asp Glu Asn Asn Trp Asp Val Asp 355 360 365 cct cgc gac ctc gct acc atc tgg cgc ggc ggc tgc atc att cgc gct 1628 Pro Arg Asp Leu Ala Thr Ile Trp Arg Gly Gly Cys Ile Ile Arg Ala 370 375 380 385 aag ttc ctc aac cgc atc gtc gaa gca tac gat gca aac gct gaa ctt 1676 Lys Phe Leu Asn Arg Ile Val Glu Ala Tyr Asp Ala Asn Ala Glu Leu 390 395 400 gag tcc ctg ctg ctc gat cct tac ttc aag agc gag ctc ggc gac ctc 1724 Glu Ser Leu Leu Leu Asp Pro Tyr Phe Lys Ser Glu Leu Gly Asp Leu 405 410 415 atc gat tca tgg cgt cgc gtg att gtc acc gcc acc cag ctt ggc ctg 1772 Ile Asp Ser Trp Arg Arg Val Ile Val Thr Ala Thr Gln Leu Gly Leu 420 425 430 cca atc cca gtg ttc gct tcc tcc ctg tcc tac tac gac agc ctg cgt 1820 Pro Ile Pro Val Phe Ala Ser Ser Leu Ser Tyr Tyr Asp Ser Leu Arg 435 440 445 gca gag cgt ctg cca gca gcc ctg atc cac tagtgtcgac ctgcaggcgc 1870 Ala Glu Arg Leu Pro Ala Ala Leu Ile His 450 455 gcgagctcca gcttttgttc cctttagtga gggttaattt cgagcttggc gtaatcaagg 1930 tcatagctgt ttcctgtgtg aaattgttat ccgctcacaa ttccacacaa tatacgagcc 1990 ggaagtataa agtgtaaagc ctggggtgcc taatgagtga gctaactcac agtaattgcg 2050 gctagcggat ctgacggttc actaaaccag ctctgcttat atagacctcc caccgtacac 2110 gcctaccgcc catttgcgtc aatggggcgg agttgttacg acattttgga aagtcccgtt 2170 gattttggtg ccaaaacaaa ctcccattga cgtcaatggg gtggagactt ggaaatcccc 2230 gtgagtcaaa ccgctatcca cgcccattga tgtactgcca aaaccgcatc accatggtaa 2290 tagcgatgac taatacgtag atgtactgcc aagtaggaaa gtccc 2335 3 459 PRT Corynebacterium glutamicum 3 Met Pro Ser Ser Thr Ile Asn Asn Met Thr Asn Gly Asp Asn Leu Ala 1 5 10 15 Gln Ile Gly Val Val Gly Leu Ala Val Met Gly Ser Asn Leu Ala Arg 20 25 30 Asn Phe Ala Arg Asn Gly Asn Thr Val Ala Val Tyr Asn Arg Ser Thr 35 40 45 Asp Lys Thr Asp Lys Leu Ile Ala Asp His Gly Ser Glu Gly Asn Phe 50 55 60 Ile Pro Ser Ala Thr Val Glu Glu Phe Val Ala Ser Leu Glu Lys Pro 65 70 75 80 Arg Arg Ala Ile Ile Met Val Gln Ala Gly Asn Ala Thr Asp Ala Val 85 90 95 Ile Asn Gln Leu Ala Asp Ala Met Asp Glu Gly Asp Ile Ile Ile Asp 100 105 110 Gly Gly Asn Ala Leu Tyr Thr Asp Thr Ile Arg Arg Glu Lys Glu Ile 115 120 125 Ser Ala Arg Gly Leu His Phe Val Gly Ala Gly Ile Ser Gly Gly Glu 130 135 140 Glu Gly Ala Leu Asn Gly Pro Ser Ile Met Pro Gly Gly Pro Ala Lys 145 150 155 160 Ser Tyr Glu Ser Leu Gly Pro Leu Leu Glu Ser Ile Ala Ala Asn Val 165 170 175 Asp Gly Thr Pro Cys Val Thr His Ile Gly Pro Asp Gly Ala Gly His 180 185 190 Phe Val Lys Met Val His Asn Gly Ile Glu Tyr Ala Asp Met Gln Val 195 200 205 Ile Gly Glu Ala Tyr His Leu Leu Pro Tyr Ala Ala Gly Met Gln Pro 210 215 220 Ala Glu Ile Ala Glu Val Phe Lys Glu Trp Asn Ala Gly Asp Leu Asp 225 230 235 240 Ser Tyr Leu Ile Glu Ile Thr Ala Glu Val Leu Ser Gln Val Asp Ala 245 250 255 Glu Thr Gly Lys Pro Leu Ile Asp Val Ile Val Asp Ala Ala Gly Gln 260 265 270 Lys Gly Thr Gly Lys Trp Thr Val Lys Ala Ala Leu Asp Leu Gly Ile 275 280 285 Ala Thr Thr Gly Ile Gly Glu Arg Val Phe Ala Arg Ala Leu Ser Gly 290 295 300 Ala Thr Ser Gln Arg Ala Ala Ala Gln Gly Asn Leu Pro Ala Gly Val 305 310 315 320 Leu Thr Asp Leu Glu Ala Leu Gly Val Asp Lys Ala Gln Phe Val Glu 325 330 335 Gly Leu Arg Arg Ala Leu Tyr Ala Ser Lys Leu Val Ala Tyr Ala Gln 340 345 350 Gly Phe Asp Glu Ile Lys Ala Gly Ser Asp Glu Asn Asn Trp Asp Val 355 360 365 Asp Pro Arg Asp Leu Ala Thr Ile Trp Arg Gly Gly Cys Ile Ile Arg 370 375 380 Ala Lys Phe Leu Asn Arg Ile Val Glu Ala Tyr Asp Ala Asn Ala Glu 385 390 395 400 Leu Glu Ser Leu Leu Leu Asp Pro Tyr Phe Lys Ser Glu Leu Gly Asp 405 410 415 Leu Ile Asp Ser Trp Arg Arg Val Ile Val Thr Ala Thr Gln Leu Gly 420 425 430 Leu Pro Ile Pro Val Phe Ala Ser Ser Leu Ser Tyr Tyr Asp Ser Leu 435 440 445 Arg Ala Glu Arg Leu Pro Ala Ala Leu Ile His 450 455 4 2160 DNA Corynebacterium glutamicum CDS (327)..(2063) poxB 4 ttagaggcga ttctgtgagg tcactttttg tggggtcggg gtctaaattt ggccagtttt 60 cgaggcgacc agacaggcgt gcccacgatg tttaaatagg cgatcggtgg gcatctgtgt 120 ttggtttcga cgggctgaaa ccaaaccaga ctgcccagca acgacggaaa tcccaaaagt 180 gggcatccct gtttggtacc gagtacccac ccgggcctga aactccctgg caggcgggcg 240 aagcgtggca acaactggaa tttaagagca caattgaagt cgcaccaagt taggcaacac 300 aatagccata acgttgagga gttcag atg gca cac agc tac gca gaa caa tta 353 Met Ala His Ser Tyr Ala Glu Gln Leu 1 5 att gac act ttg gaa gct caa ggt gtg aag cga att tat ggt ttg gtg 401 Ile Asp Thr Leu Glu Ala Gln Gly Val Lys Arg Ile Tyr Gly Leu Val 10 15 20 25 ggt gac agc ctt aat ccg atc gtg gat gct gtc cgc caa tca gat att 449 Gly Asp Ser Leu Asn Pro Ile Val Asp Ala Val Arg Gln Ser Asp Ile 30 35 40 gag tgg gtg cac gtt cga aat gag gaa gcg gcg gcg ttt gca gcc ggt 497 Glu Trp Val His Val Arg Asn Glu Glu Ala Ala Ala Phe Ala Ala Gly 45 50 55 gcg gaa tcg ttg atc act ggg gag ctg gca gta tgt gct gct tct tgt 545 Ala Glu Ser Leu Ile Thr Gly Glu Leu Ala Val Cys Ala Ala Ser Cys 60 65 70 ggt cct gga aac aca cac ctg att cag ggt ctt tat gat tcg cat cga 593 Gly Pro Gly Asn Thr His Leu Ile Gln Gly Leu Tyr Asp Ser His Arg 75 80 85 aat ggt gcg aag gtg ttg gcc atc gct agc cat att ccg agt gcc cag 641 Asn Gly Ala Lys Val Leu Ala Ile Ala Ser His Ile Pro Ser Ala Gln 90 95 100 105 att ggt tcg acg ttc ttc cag gaa acg cat ccg gag att ttg ttt aag 689 Ile Gly Ser Thr Phe Phe Gln Glu Thr His Pro Glu Ile Leu Phe Lys 110 115 120 gaa tgc tct ggt tac tgc gag atg gtg aat ggt ggt gag cag ggt gaa 737 Glu Cys Ser Gly Tyr Cys Glu Met Val Asn Gly Gly Glu Gln Gly Glu 125 130 135 cgc att ttg cat cac gcg att cag tcc acc atg gcg ggt aaa ggt gtg 785 Arg Ile Leu His His Ala Ile Gln Ser Thr Met Ala Gly Lys Gly Val 140 145 150 tcg gtg gta gtg att cct ggt gat atc gct aag gaa gac gca ggt gac 833 Ser Val Val Val Ile Pro Gly Asp Ile Ala Lys Glu Asp Ala Gly Asp 155 160 165 ggt act tat tcc aat tcc act att tct tct ggc act cct gtg gtg ttc 881 Gly Thr Tyr Ser Asn Ser Thr Ile Ser Ser Gly Thr Pro Val Val Phe 170 175 180 185 ccg gat cct act gag gct gca gcg ctg gtg gag gcg att aac aac gct 929 Pro Asp Pro Thr Glu Ala Ala Ala Leu Val Glu Ala Ile Asn Asn Ala 190 195 200 aag tct gtc act ttg ttc tgc ggt gcg ggc gtg aag aat gct cgc gcg 977 Lys Ser Val Thr Leu Phe Cys Gly Ala Gly Val Lys Asn Ala Arg Ala 205 210 215 cag gtg ttg gag ttg gcg gag aag att aaa tca ccg atc ggg cat gcg 1025 Gln Val Leu Glu Leu Ala Glu Lys Ile Lys Ser Pro Ile Gly His Ala 220 225 230 ctg ggt ggt aag cag tac atc cag cat gag aat ccg ttt gag gtc ggc 1073 Leu Gly Gly Lys Gln Tyr Ile Gln His Glu Asn Pro Phe Glu Val Gly 235 240 245 atg tct ggc ctg ctt ggt tac ggc gcc tgc gtg gat gcg tcc aat gag 1121 Met Ser Gly Leu Leu Gly Tyr Gly Ala Cys Val Asp Ala Ser Asn Glu 250 255 260 265 gcg gat ctg ctg att cta ttg ggt acg gat ttc cct tat tct gat ttc 1169 Ala Asp Leu Leu Ile Leu Leu Gly Thr Asp Phe Pro Tyr Ser Asp Phe 270 275 280 ctt cct aaa gac aac gtt gcc cag gtg gat atc aac ggt gcg cac att 1217 Leu Pro Lys Asp Asn Val Ala Gln Val Asp Ile Asn Gly Ala His Ile 285 290 295 ggt cga cgt acc acg gtg aag tat ccg gtg acc ggt gat gtt gct gca 1265 Gly Arg Arg Thr Thr Val Lys Tyr Pro Val Thr Gly Asp Val Ala Ala 300 305 310 aca atc gaa aat att ttg cct cat gtg aag gaa aaa aca gat cgt tcc 1313 Thr Ile Glu Asn Ile Leu Pro His Val Lys Glu Lys Thr Asp Arg Ser 315 320 325 ttc ctt gat cgg atg ctc aag gca cac gag cgt aag ttg agc tcg gtg 1361 Phe Leu Asp Arg Met Leu Lys Ala His Glu Arg Lys Leu Ser Ser Val 330 335 340 345 gta gag acg tac aca cat aac gtc gag aag cat gtg cct att cac cct 1409 Val Glu Thr Tyr Thr His Asn Val Glu Lys His Val Pro Ile His Pro 350 355 360 gaa tac gtt gcc tct att ttg aac gag ctg gcg gat aag gat gcg gtg 1457 Glu Tyr Val Ala Ser Ile Leu Asn Glu Leu Ala Asp Lys Asp Ala Val 365 370 375 ttt act gtg gat acc ggc atg tgc aat gtg tgg cat gcg agg tac atc 1505 Phe Thr Val Asp Thr Gly Met Cys Asn Val Trp His Ala Arg Tyr Ile 380 385 390 gag aat ccg gag gga acg cgc gac ttt gtg ggt tca ttc cgc cac ggc 1553 Glu Asn Pro Glu Gly Thr Arg Asp Phe Val Gly Ser Phe Arg His Gly 395 400 405 acg atg gct aat gcg ttg cct cat gcg att ggt gcg caa agt gtt gat 1601 Thr Met Ala Asn Ala Leu Pro His Ala Ile Gly Ala Gln Ser Val Asp 410 415 420 425 cga aac cgc cag gtg atc gcg atg tgt ggc gat ggt ggt ttg ggc atg 1649 Arg Asn Arg Gln Val Ile Ala Met Cys Gly Asp Gly Gly Leu Gly Met 430 435 440 ctg ctg ggt gag ctt ctg acc gtt aag ctg cac caa ctt ccg ctg aag 1697 Leu Leu Gly Glu Leu Leu Thr Val Lys Leu His Gln Leu Pro Leu Lys 445 450 455 gct gtg gtg ttt aac aac agt tct ttg ggc atg gtg aag ttg gag atg 1745 Ala Val Val Phe Asn Asn Ser Ser Leu Gly Met Val Lys Leu Glu Met 460 465 470 ctc gtg gag gga cag cca gaa ttt ggt act gac cat gag gaa gtg aat 1793 Leu Val Glu Gly Gln Pro Glu Phe Gly Thr Asp His Glu Glu Val Asn 475 480 485 ttc gca gag att gcg gcg gct gcg ggt atc aaa tcg gta cgc atc acc 1841 Phe Ala Glu Ile Ala Ala Ala Ala Gly Ile Lys Ser Val Arg Ile Thr 490 495 500 505 gat ccg aag aaa gtt cgc gag cag cta gct gag gca ttg gca tat cct 1889 Asp Pro Lys Lys Val Arg Glu Gln Leu Ala Glu Ala Leu Ala Tyr Pro 510 515 520 gga cct gta ctg atc gat atc gtc acg gat cct aat gcg ctg tcg atc 1937 Gly Pro Val Leu Ile Asp Ile Val Thr Asp Pro Asn Ala Leu Ser Ile 525 530 535 cca cca acc atc acg tgg gaa cag gtc atg gga ttc agc aag gcg gcc 1985 Pro Pro Thr Ile Thr Trp Glu Gln Val Met Gly Phe Ser Lys Ala Ala 540 545 550 acc cga acc gtc ttt ggt gga gga gta gga gcg atg atc gat ctg gcc 2033 Thr Arg Thr Val Phe Gly Gly Gly Val Gly Ala Met Ile Asp Leu Ala 555 560 565 cgt tcg aac ata agg aat att cct act cca tgatgattga tacacctgct 2083 Arg Ser Asn Ile Arg Asn Ile Pro Thr Pro 570 575 gttctcattg accgcgagcg cttaactgcc aacatttcca ggatggcagc tcacgccggt 2143 gcccatgaga ttgccct 2160 5 579 PRT Corynebacterium glutamicum 5 Met Ala His Ser Tyr Ala Glu Gln Leu Ile Asp Thr Leu Glu Ala Gln 1 5 10 15 Gly Val Lys Arg Ile Tyr Gly Leu Val Gly Asp Ser Leu Asn Pro Ile 20 25 30 Val Asp Ala Val Arg Gln Ser Asp Ile Glu Trp Val His Val Arg Asn 35 40 45 Glu Glu Ala Ala Ala Phe Ala Ala Gly Ala Glu Ser Leu Ile Thr Gly 50 55 60 Glu Leu Ala Val Cys Ala Ala Ser Cys Gly Pro Gly Asn Thr His Leu 65 70 75 80 Ile Gln Gly Leu Tyr Asp Ser His Arg Asn Gly Ala Lys Val Leu Ala 85 90 95 Ile Ala Ser His Ile Pro Ser Ala Gln Ile Gly Ser Thr Phe Phe Gln 100 105 110 Glu Thr His Pro Glu Ile Leu Phe Lys Glu Cys Ser Gly Tyr Cys Glu 115 120 125 Met Val Asn Gly Gly Glu Gln Gly Glu Arg Ile Leu His His Ala Ile 130 135 140 Gln Ser Thr Met Ala Gly Lys Gly Val Ser Val Val Val Ile Pro Gly 145 150 155 160 Asp Ile Ala Lys Glu Asp Ala Gly Asp Gly Thr Tyr Ser Asn Ser Thr 165 170 175 Ile Ser Ser Gly Thr Pro Val Val Phe Pro Asp Pro Thr Glu Ala Ala 180 185 190 Ala Leu Val Glu Ala Ile Asn Asn Ala Lys Ser Val Thr Leu Phe Cys 195 200 205 Gly Ala Gly Val Lys Asn Ala Arg Ala Gln Val Leu Glu Leu Ala Glu 210 215 220 Lys Ile Lys Ser Pro Ile Gly His Ala Leu Gly Gly Lys Gln Tyr Ile 225 230 235 240 Gln His Glu Asn Pro Phe Glu Val Gly Met Ser Gly Leu Leu Gly Tyr 245 250 255 Gly Ala Cys Val Asp Ala Ser Asn Glu Ala Asp Leu Leu Ile Leu Leu 260 265 270 Gly Thr Asp Phe Pro Tyr Ser Asp Phe Leu Pro Lys Asp Asn Val Ala 275 280 285 Gln Val Asp Ile Asn Gly Ala His Ile Gly Arg Arg Thr Thr Val Lys 290 295 300 Tyr Pro Val Thr Gly Asp Val Ala Ala Thr Ile Glu Asn Ile Leu Pro 305 310 315 320 His Val Lys Glu Lys Thr Asp Arg Ser Phe Leu Asp Arg Met Leu Lys 325 330 335 Ala His Glu Arg Lys Leu Ser Ser Val Val Glu Thr Tyr Thr His Asn 340 345 350 Val Glu Lys His Val Pro Ile His Pro Glu Tyr Val Ala Ser Ile Leu 355 360 365 Asn Glu Leu Ala Asp Lys Asp Ala Val Phe Thr Val Asp Thr Gly Met 370 375 380 Cys Asn Val Trp His Ala Arg Tyr Ile Glu Asn Pro Glu Gly Thr Arg 385 390 395 400 Asp Phe Val Gly Ser Phe Arg His Gly Thr Met Ala Asn Ala Leu Pro 405 410 415 His Ala Ile Gly Ala Gln Ser Val Asp Arg Asn Arg Gln Val Ile Ala 420 425 430 Met Cys Gly Asp Gly Gly Leu Gly Met Leu Leu Gly Glu Leu Leu Thr 435 440 445 Val Lys Leu His Gln Leu Pro Leu Lys Ala Val Val Phe Asn Asn Ser 450 455 460 Ser Leu Gly Met Val Lys Leu Glu Met Leu Val Glu Gly Gln Pro Glu 465 470 475 480 Phe Gly Thr Asp His Glu Glu Val Asn Phe Ala Glu Ile Ala Ala Ala 485 490 495 Ala Gly Ile Lys Ser Val Arg Ile Thr Asp Pro Lys Lys Val Arg Glu 500 505 510 Gln Leu Ala Glu Ala Leu Ala Tyr Pro Gly Pro Val Leu Ile Asp Ile 515 520 525 Val Thr Asp Pro Asn Ala Leu Ser Ile Pro Pro Thr Ile Thr Trp Glu 530 535 540 Gln Val Met Gly Phe Ser Lys Ala Ala Thr Arg Thr Val Phe Gly Gly 545 550 555 560 Gly Val Gly Ala Met Ile Asp Leu Ala Arg Ser Asn Ile Arg Asn Ile 565 570 575 Pro Thr Pro 6 875 DNA Corynebacterium glutamicum 6 tgcgagatgg tgaatggtgg tgagcagggt gaacgcattt tgcatcacgc gattcagtcc 60 accatggcgg gtaaaggtgt gtcggtggta gtgattcctg gtgatatcgc taaggaagac 120 gcaggtgacg gtacttattc caattccact atttcttctg gcactcctgt ggtgttcccg 180 gatcctactg aggctgcagc gctggtggag gcgattaaca acgctaagtc tgtcactttg 240 ttctgcggtg cgggcgtgaa gaatgctcgc gcgcaggtgt tggagttggc ggagaagatt 300 aaatcaccga tcgggcatgc gctgggtggt aagcagtaca tccagcatga gaatccgttt 360 gaggtcggca tgtctggcct gcttggttac ggcgcctgcg tggatgcgtc caatgaggcg 420 gatctgctga ttctattggg tacggatttc ccttattctg atttccttcc taaagacaac 480 gttgcccagg tggatatcaa cggtgcgcac attggtcgac gtaccacggt gaagtatccg 540 gtgaccggtg atgttgctgc aacaatcgaa aatattttgc ctcatgtgaa ggaaaaaaca 600 gatcgttcct tccttgatcg gatgctcaag gcacacgagc gtaagttgag ctcggtggta 660 gagacgtaca cacataacgt cgagaagcat gtgcctattc accctgaata cgttgcctct 720 attttgaacg agctggcgga taaggatgcg gtgtttactg tggataccgg catgtgcaat 780 gtgtggcatg cgaggtacat cgagaatccg gagggaacgc gcgactttgt gggttcattc 840 cgccacggca cgatggctaa tgcgttgcct catgc 875 7 23 DNA Artificial sequence Description of artificial sequence Primer gnd1 7 atggtkcaca cyggyatyga rta 23 8 21 DNA Artificial sequence Description of artificial sequence Primer gnd2 8 rgtccayttr ccrgtrccyt t 21 9 17 DNA Artificial sequence Description of artificial sequence Internal primer 1 9 ggtggatgct gaaaccg 17 10 17 DNA Artificial sequence Description of artificial sequence Internal primer 2 10 gctgcatgcc tgctgcg 17 11 17 DNA Artificial sequence Description of artificial sequence Internal primer 3 11 ttgttgctta cgcacag 17 12 17 DNA Artificial sequence Description of artificial sequence Internal primer 4 12 tcgtaggact ttgctgg 17 13 21 DNA Artificial sequence Description of artificial sequence gnd fwd. primer 13 actctagtcg gcctaaaatg g 21 14 21 DNA Artificial sequence Description of artificial sequence gnd rev. primer 14 cacacaggaa acagatatga c 21 15 20 DNA Artificial sequence Description of artificial sequence Primer poxBint1 15 tgcgagatgg tgaatggtgg 20 16 20 DNA Artificial sequence Description of artificial sequence Primer poxBint2 16 gcatgaggca acgcattagc 20
The invention relates to a process for the preparation of L-amino acids. The process involves fermenting an L-amino acid producing coryneform bacteria in a culture medium, concentrating L-amino acid produced by the fermenting in the culture medium or in the cells of the bacteria, and isolating the L-amino acid produced. The bacteria has an overexpressed gene encoding 6-phosphogluconate dehydrogenase and a decreased or switched off gene encoding pyruvate oxidase. The L-amino acid may be L-lysine, L-threonine, L-isoleucine or L-tryptophan. `
Provide a concise summary of the essential information conveyed in the context.
[ "CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation-in-part of U.S. application Ser.", "No. 09/531,265, filed on Mar. 20, 2000, the contents of which are incorporated by reference herein in their entirety.", "FIELD OF THE INVENTION [0002] The invention relates to a process for the fermentative preparation of L-amino acids, in particular L-lysine, L-threonine, L-isoleucine and L-tryptophan, using coryneform bacteria in which at least the enzyme 6-phosphogluconate dehydrogenase encoded by the gnd gene is amplified.", "BACKGROUND [0003] L-Amino acids are used in animal nutrition, in human medicine and in the pharmaceuticals industry and are prepared by fermentation from strains of coryneform bacteria, in particular Corynebacterium glutamicum .", "Because of their great importance, work is constantly being undertaken to improve the preparation processes.", "Improvements may relate to fermentation measures, e.g., stirring and supply of oxygen;", "the composition of the nutrient media, e.g., the sugar concentration during the fermentation;", "the working up to the product form, e.g., by ion exchange chromatography;", "or the intrinsic output properties of the microorganism itself.", "[0004] Methods of mutagenesis, selection and mutant selection are used to improve the output properties of these microorganisms.", "Strains which are resistant to antimetabolites (e.g., the threonine analogue α-amino-β-hydroxyvaleric acid (AHV), and the lysine analogue S-(2-aminoethyl)-L-cystein (AEC)) or which are auxotrophic for metabolites of regulatory importance and produce L-amino acids such as threonine `or lysine are obtained in this manner.", "[0005] Methods utilizing recombinant DNA techniques have also been employed for some years for improving Corynebacterium glutamicum strains which produce L-amino acids.", "SUMMARY OF THE INVENTION [0006] L-Amino acids are used in human medicine and in the pharmaceuticals industry, in the foodstuffs industry and especially in animal nutrition.", "There is therefore a general interest in providing improved processes for their preparation.", "[0007] In general, the present invention is directed to improved processes for the fermentative preparation of L-amino acids by coryneform bacteria.", "More specifically, the invention provides a process for the fermentative preparation of L-amino acids (particularly L-lysine, L-threonine, L-isoleucine and L-tryptophan) using coryneform bacteria in which the nucleotide sequence which codes for the enzyme 6-phosphogluconate dehydrogenase (EC number 1.1[.", "].1.44) (gnd gene) is amplified, in particular over-expressed.", "BRIEF DESCRIPTION OF THE FIGURES [0008] Embodiments of the present invention will be described with reference to the following Figures, in which: [0009] [0009 ]FIG. 1 is a map of the plasmid pEC-T18mob2;", "[0010] [0010 ]FIG. 2 is a map of the plasmid pECgnd;", "[0011] [0011 ]FIG. 3 is a map of the plasmid pBGNA;", "and [0012] [0012 ]FIG. 4 is a map of the plasmid pCR2.1poxBint.", "DETAILED DESCRIPTION OF THE INVENTION [0013] The strains of bacteria employed in the present processes preferably already produce L-amino acids before amplification of the gnd gene.", "The term `“amplification”", "as used herein describes the increase in the intracellular activity of one or more enzymes or proteins in a microorganism which are encoded by the corresponding DNA.", "This may be accomplished, for example, by increasing the number of copies of the gene or genes, using a potent promoter or using a gene which codes for a corresponding enzyme having a high activity, or by combining these measures.", "[0014] By amplification measures, in particular over-expression, the activity or concentration of the corresponding enzyme or protein is in general increased by at least 10%, 25%, 50%, 75%, 100%, 150%, 200%, 300%, 400% or 500%, up to a maximum of 1000% or 2000%, compared to that of the wild-type enzyme or the activity or concentration of the enzyme in the starting microorganism.", "[0015] The microorganisms which the present invention provide can prepare L-amino acids from glucose, sucrose, lactose, fructose, maltose, molasses, starch, cellulose or from glycerol and ethanol.", "They are representatives of coryneform bacteria, in particular of the genus Corynebacterium.", "Of the genus Corynebacterium, the most preferred species is Corynebacterium glutamicum , which is known among experts for its ability to produce L-amino acids.", "Suitable strains include the wild-type strains: [0016] [0016] Corynebacterium glutamicum ATCC13032;", "[0017] [0017] Corynebacterium acetoglutamicum ATCC 15806;", "[0018] [0018] Corynebacterium acetoacidophilum ATCC13870;", "[0019] [0019] Corynebacterium thermoaminogenes FERM BP-1539;", "[0020] [0020] Brevibacterium flavum ATCC14067;", "[0021] [0021] Brevibacterium lactofermentum ATCC13869;", "[0022] Brevibacterium divaricatum ATCC14020;", "[0023] L-amino acid-producing mutants prepared from the strains above may also be used.", "Such strains include: the L-threonine-producing strains: [0024] [0024] Corynebacterium glutamicum ATCC21649;", "[0025] [0025] Brevibacterium flavum BB69;", "[0026] [0026] Brevibacterium flavum DSM5399;", "[0027] [0027] Brevibacterium lactofermentum FERM-BP 269;", "[0028] [0028] Brevibacterium lactofermentum TBB- 10;", "` [0029] the L-isoleucine-producing strains: [0030] [0030] Corynebacterium glutamicum ATCC 14309;", "[0031] [0031] Corynebacterium glutamicum ATCC 14310;", "[0032] [0032] Corynebacterium glutamicum ATCC 14311;", "[0033] [0033] Corynebacterium glutamicum ATCC 15168;", "[0034] [0034] Corynebacterium ammoniagenes ATCC 6871;", "[0035] the L-tryptophan-producing strains: [0036] [0036] Corynebacterium glutamicum ATCC21850;", "[0037] [0037] Corynebacterium glutamicum KY9218(pKW9901);", "[0038] and the L-lysine-producing strains: [0039] [0039] Corynebacterium glutamicum FERM-P 1709;", "[0040] [0040] Brevibacterium flavum FERM-P 1708;", "[0041] [0041] Brevibacterium lactofermentum FERM-P 1712;", "[0042] [0042] Corynebacterium glutamicum FERM-P 6463;", "[0043] [0043] Corynebacterium glutamicum FERM-P 6464;", "[0044] [0044] Corynebacterium glutamicum DSM5715;", "[0045] [0045] Corynebacterium glutamicum DM58-1;", "and [0046] [0046] Corynebacterium glutamicum DSM12866.", "[0047] It has been found that coryneform bacteria produce L-amino acids, in particular L-lysine, L-threonine, L-isoleucine and L-tryptophan, in an improved manner after over-expression of the gnd gene.", "The gnd gene codes for the enzyme 6-phosphogluconate dehydrogenase (EC number 1.1[.", "].1.44) which catalyses the oxidative decarboxylation of 6-phosphogluconic acid to ribulose 5-phosphate.", "The nucleotide sequence of the gnd gene is disclosed in JP-A-9-224662.", "Alleles of the gnd gene which result from the degeneracy of the genetic code or which are due to sense mutations of neutral function can furthermore be used.", "Genes encoding proteins with 6-phosphogluconate dehydrogenase activity from Gram-negative bacteria, e.g. Escherichia coli , or other Gram-positive bacteria, e.g., Streptomyces or Bacillus, may optionally be used.", "[0048] The use of endogenous, genes in particular endogenous genes from `coryneform bacteria, is preferred.", "The terms “endogenous genes”", "or “endogenous nucleotide sequences”", "refer to genes or nucleotide sequences which are available in the population of a species.", "[0049] To achieve an amplification (e.g., over-expression) of a protein, the number of copies of the corresponding gene is increased, or the promoter and regulation region or the ribosome binding site upstream of the structural gene are mutated.", "Expression cassettes which are incorporated upstream of the structural gene act in the same way.", "Using inducible promoters, it is additionally possible to increase the expression in the course of fermentative L-amino acid formation.", "Expression may also be improved by measures to prolong the life of the m-RNA.", "Enzyme activity may be increased by preventing the degradation of the enzyme protein.", "[0050] Genes or gene constructs may either be provided in plasmids with a varying number of copies, or may be integrated and amplified in the chromosome.", "Alternatively, an over-expression of the genes in question can be achieved by changing the composition of the media and the culture procedure.", "Instructions in this context can be found by the expert, inter alia, in Martin et al.", "(Bio/Technology 5, 137-146 (1987)), in Guerrero et al.", "(Gene 138, 35-41 (1994)), Tsuchiya and Morinaga (Bio/Technology 6, 428-430 (1988)), in Eikmanns et al.", "(Gene 102, 93-98 (1991)), in European Patent Specification EPS 0 472 869, in U.S. Pat. No. 4,601,893, in Schwarzer and Pühler (Bio/Technology 9, 84-87 (1991), in Reinscheid et al.", "(Applied and Environmental Microbiology 60, 126-132 (1994)), in LaBarre et al.", "(Journal of Bacteriology 175, 1001-1007 (1993)), in Patent Application WO 96/15246, in Malumbres et al.", "(Gene 134, 15-24 (1993)), in Japanese Laid-Open Specification JP-A-10-229891, in Jensen and Hammer (Biotechnology and Bioengineering 58, 191-195 (1998)) and in known textbooks of genetics and molecular biology.", "[0051] By way of example, 6-phosphogluconate dehydrogenase was over-expressed with the aid of a plasmid.", "The E. coli - C. glutamicum shuttle vector pEC-T18mob2 shown in FIG. 1 was used for this.", "After incorporation of the gnd gene into the EcoRI cleavage site of pEC-T18mob2, the plasmid pECgnd shown in FIG. 2 was `formed.", "Other plasmid vectors which are capable of replication in C. glutamicum , such as pEKEx1 (Eikmanns et al.", ", Gene 102:93-98 (1991)) or pZ8-1 (EP-B-0 375 889), can be used in the same way.", "[0052] In addition, it may be advantageous for the production of L-amino acids to amplify one or more enzymes of the relevant biosynthesis pathway, of glycolysis, of anaplerosis, of the pentose phosphate pathway or of amino acid export, in addition to amplification of the gnd gene.", "For example, for the preparation of L-threonine, one or more of the following genes can be amplified (over-expressed): [0053] the hom gene which codes for homoserine dehydrogenase (Peoples et al.", ", Molecular Microbiology 2, 63-72 (1988)) or the hom dr allele which codes for a “feed back resistant”", "homoserine dehydrogenase (Archer et al.", ", Gene 107, 53-59 (1991), [0054] the gap gene which codes for glyceraldehyde 3-phosphate dehydrogenase (Eikmanns et al.", ", Journal of Bacteriology 174: 6076-6086 (1992)), [0055] the pyc gene which codes for pyruvate carboxylase (Peters-Wendisch et al.", ", Microbiology 144: 915-927 (1998)), [0056] the mqo gene which codes for malate:quinone oxidoreductase (Molenaar et al.", ", European Journal of Biochemistry 254, 395-403 (1998)), [0057] the tkt gene which codes for transketolase (accession number AB023377 of the databank of European Molecular Biology Laboratories (EMBL, Heidelberg, Germany)), [0058] the zwf gene which codes for glucose 6-phosphate dehydrogenase (JP-A-09224661), [0059] the thrE gene which codes for threonine export (DE 199 41 478.5;", "DSM 12840), [0060] the zwa1 gene (DE 199 59 328.0;", "DSM 13115), [0061] the eno gene which codes for enolase (DE: 199 41 478.5).", "[0062] For the preparation of L-lysine, one or more of the following genes can be amplified, in particular over-expressed, at the same time as gnd.", "[0063] the dapA gene which codes for dihydrodipicolinate synthase (EP-B 0 197 335), [0064] a lysC gene which codes for a feed back resistant aspartate kinase (Kalinowski et al.", "(1990), Molecular and General Genetics 224: 317-324), [0065] the gap gene which codes for glyceraldehyde 3-phosphate dehydrogenase (Eikmanns `(1992), Journal of Bacteriology 174:6076-6086), [0066] the pyc gene which codes for pyruvate carboxylase (Eikmanns (1992), Journal of Bacteriology 174:6076-6086), [0067] the mqo gene which codes for malate-quinone oxidoreductase (Molenaar et al.", ", European Journal of Biochemistry 254, 395-403 (1998)), [0068] the tkt gene which codes for transketolase (accession number AB023377 of the databank of European Molecular Biologies Laboratories (EMBL, Heidelberg, Germany)), [0069] the zwf gene which codes for glucose 6-phosphate dehydrogenase (JP-A-09224661), [0070] the lysE gene which codes for lysine export [0071] (DE-A-195 48 222), [0072] the zwa1 gene (DE 199 59 328.0;", "DSM 13115), [0073] the eno gene which codes for enolase (DE 199 47 791.4).", "[0074] The use of endogenous genes is preferred.", "[0075] It may furthermore be advantageous for the production of L-amino acids to attenuate one or more of the following genes while at the same time amplifying gnd: [0076] the pck gene which codes for phosphoenol pyruvate carboxykinase (DE 199 50 409.1;", "DSM 13047), [0077] the pgi gene which codes for glucose 6-phosphate isomerase (U.S. Ser.", "No. 09/396,478, DSM 12969), [0078] the poxB gene which codes for pyruvate oxidase [0079] (DE 199 51 975.7;", "DSM 13114), [0080] the zwa2 gene (DE: 199 59 327.2;", "DSM 13113).", "[0081] In this connection, the term “attenuation”", "means reducing or suppressing the intracellular activity or concentration of one or more enzymes or proteins in a microorganism.", "This may be accomplished using the genes which encode the proteins, for example by using a weak promoter or a gene or allele which codes for a corresponding protein which has a low activity or inactivates the corresponding enzyme and optionally by combining these measures.", "By attenuation measures, the activity or concentration of the corresponding enzyme or protein is in general reduced to 0 to 75%, `0 to 50%, 0 to 25%, 0 to 10% or 0 to 5% of the activity or concentration of the wild-type enzyme or of the activity or concentration of the enzyme in the starting microorganism.", "[0082] In addition to over-expression of 6-phosphogluconate dehydrogenase, it may furthermore be advantageous for the production of L-amino acids to eliminate undesirable side reactions (see, Nakayama: “Breeding of Amino Acid Producing Microorganisms,” in: Overproduction of Microbial Products, Krumphanzl, Sikyta, Vanek (eds.), Academic Press, London, UK, 1982).", "[0083] The microorganisms prepared according to the invention can be cultured continuously or discontinuously in a batch process (batch culture) or in a fed batch (feed process) or repeated fed batch process (repetitive feed process) for the purpose of L-amino acid production.", "A summary of known culture methods is described in the textbook by Chmiel (Bioprozesstechnik 1.", "Einführung in die Bioverfahrenstechnik [Bioprocess Technology 1.", "Introduction to Bioprocess Technology (Gustav Fischer Verlag, Stuttgart, 1991)) or in the textbook by Storhas (Bioreaktoren und periphere Einrichtungen [Bioreactors and Peripheral Equipment] (Vieweg Verlag, Braunschweig/Wiesbaden, 1994)).", "The culture medium to be used must meet the requirements of the particular microorganisms in a suitable manner.", "Descriptions of culture media for various microorganisms are contained in the handbook “Manual of Methods for General Bacteriology”", "of the American Society for Bacteriology (Washington D.C., USA, 1981).", "Sugars and carbohydrates, such as e.g. glucose, sucrose, lactose, fructose, maltose, molasses, starch and cellulose, oils and fats, such as e.g. soya oil, sunflower oil, groundnut oil and coconut fat, fatty acids, such as e.g. palmitic acid, stearic acid and linoleic acid, alcohols, such as e.g. glycerol and ethanol, and organic acids, such as e.g. acetic acid, can be used as the source of carbon.", "These substances can be used individually or as a mixture.", "Organic nitrogen-containing compounds, such as peptones, yeast extract, meat extract, malt extract, corn steep liquor, soya bean flour and urea, or inorganic compounds, such as ammonium sulfate, ammonium chloride, ammonium phosphate, ammonium carbonate and ammonium nitrate, can be used as the source of nitrogen.", "The sources of nitrogen can be used individually or as a mixture.", "Potassium dihydrogen phosphate or dipotassium hydrogen `phosphate or the corresponding sodium-containing salts can be used as the source of phosphorus.", "The culture medium must furthermore comprise salts of metals, such as e.g. magnesium sulfate or iron sulfate, which are necessary for growth.", "Finally, essential growth substances, such as amino acids and vitamins, can be employed in addition to the above-mentioned substances.", "Suitable precursors can moreover be added to the culture medium.", "The starting substances mentioned can be added to the culture in the form of a single batch, or can be fed in during the culture in a suitable manner.", "[0084] Basic compounds, such as sodium hydroxide, potassium hydroxide, ammonia, or acid compounds, such as phosphoric acid or sulfuric acid, can be employed in a suitable manner to control the pH.", "Antifoams, such as fatty acid polyglycol esters, can be employed to control the development of foam.", "Suitable substances having a selective action, e.g. antibiotics, can be added to the medium to maintain the stability of plasmids.", "To maintain aerobic conditions, oxygen or oxygen-containing gas mixtures, such as e.g. air, are introduced into the culture.", "The temperature of the culture is usually 20° C. to 45° C., and preferably 25° C. to 40° C. Culturing is continued until a maximum of L-amino acid has formed.", "This target is usually reached within 10 hours to 160 hours.", "[0085] The analysis of L-amino acids can be carried out by anion exchange chromatography with subsequent ninhydrin derivation, as described by Spackman et al.", "(Analytical Chemistry, 30, (1958), 1190), or it can take place by reversed phase HPLC as described by Lindroth et al.", "(Analytical Chemistry (1979) 51:.", "1167-1174).", "[0086] The following microorganism has been deposited at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) in accordance with the Budapest Treaty: Escherichia coli K-12 DH5α/pEC-T18mob2 as DSM 13244.", "[0087] In the accompanying Figures, the base pair numbers stated are approx.", "values obtained in the context of reproducibility.", "The abbreviations used in the Figures have the following meaning: ` In FIG. 1: Tet: Resistance gene for tetracycline oriV: Plasmid-coded replication origin of E. coli RP4mob: mob region for mobilizing the plasmid rep: Plasmid-coded replication origin from C. glutamicum plasmid pGA1 per: Gene for controlling the number of copies from pGA1 lacZ-alpha: lacZα gene fragment (N-terminus) of the β-Galactosidase gene.", "In FIG. 2: Tet: Resistance gene for tetracycline rep: Plasmid-coded replication origin from C. glutamicum plasmid pGA1 per: Gene for controlling the number of copies from PGA1 lacZ Cloning relict of the lacZα gene fragment from pEC-T18mob2 gnd: 6-Phosphogluconate dehydrogenase gene.", "In FIG. 3: LacP: Promoter of the E. coli lactose operon CMV: Promoter of cytomegalovirus ColE1: Replication origin of the plasmid ColE1 TkpolyA: Polyadenylation site Kan r: Kanamycin resistance gene SV40ori: Replication origin of Simian virus 40 gnd: 6-Phosphogluconate dehydrogenase gene.", "In FIG. 4: ColE1 ori: Replication origin of the plasmid ColE1 lacZ: Cloning relict of the lacZα gene fragment fl ori: Replication origin of phage f1 KmR: Kanamycin resistance ApR: Ampicillin resistance poxBint: internal fragment of the poxB gene [0088] The following abbreviations have also been used herein: AccI: Cleavage site of the restriction enzyme AccI BamHI: Cleavage site of the restriction enzyme BamHI EcoRI: Cleavage site of the restriction enzyme EcoRI HindIII: Cleavage site of the restriction enzyme HindIII KpnI: Cleavage site of the restriction enzyme KpnI PstI: Cleavage site of the restriction enzyme PstI PvuI: Cleavage site of the restriction enzyme PvuI SalI: Cleavage site of the restriction enzyme SalI SacI: Cleavage site of the restriction enzyme SacI SmaI: Cleavage site of the restriction enzyme SmaI SphI: Cleavage site of the restriction enzyme SphI XbaI: Cleavage site of the restriction enzyme XbaI XhoI: Cleavage site of the restriction enzyme XhoI [0089] The following examples will further illustrate this invention.", "The molecular biology techniques, e.g. plasmid DNA isolation, restriction enzyme treatment, ligations, standard transformations of Escherichia coli etc.", "used are, (unless stated otherwise), are described by Sambrook et al.", ", (Molecular Cloning.", "A Laboratory Manual (1989) Cold Spring Harbor Laboratories, USA).", "EXAMPLE 1 Construction of a Gene Library of Corynebacterium glutamicum Strain AS019 [0090] A DNA library of Corynebacterium glutamicum strain AS019 (Yoshihama et al.", ", Journal of Bacteriology 162, 591-597 (1985)) was constructed using λ Zap Express™ system, (Short et al.", ", (1988) Nucleic Acids Research 16: 7583-7600), as described by O'Donohue (O'Donohue, M. (1997).", "The Cloning and Molecular Analysis of Four Common Aromatic Amino Acid Biosynthetic Genes from Corynebacterium glutamicum.", "Ph.D. Thesis, National University of Ireland, Galway).", "λ Zap Express™ kit was purchased from Stratagene (Stratagene, 11011 North Torrey Pines Rd.", ", La Jolla, Calif.", "92037) and used according to the manufacturer's instructions.", "AS019-DNA was digested with restriction enzyme Sau3A and ligated to `BamHI treated and dephosphorylated λ Zap Express™ arms.", "EXAMPLE 2 Cloning and Sequencing of the gnd Gene [0091] 2.1 Construction of a gnd Probe [0092] A radio-labeled oligonucleotide, internal to the gnd gene, was used to probe the AS019 λ Zap Express™ library described above.", "The oligonucleotide was produced using degenerate PCR primers internal to the gnd gene.", "The degenerate nucleotide primers designed for the PCR amplification of gnd DNA fragments were as follows: [0093] gnd1: 5′ ATG GTK CAC ACY GGY ATY GAR TA 3′ (SEQ ID NO 7) [0094] gnd2: 5′ RGT CCA YTT RCC RGT RCC YTT 3′ (SEQ ID NO 8) [0095] with R=A+G;", "Y=C+T;", "K=T+G.", "[0096] The estimated size of the resulting PCR product was 252 bp approximately.", "Optimal PCR conditions were determined to be as follows: [0097] 35 cycles [0098] 94° C. for 1 minute [0099] 55° C. for 1 minute [0100] 72° C. for 30 seconds [0101] 2.5-3.5 mM MgCl 2 [0102] 100-150 ng AS019 genomic DNA.", "[0103] Sequence analysis of the resulting PCR product confirmed the product to be an internal portion of a gnd gene.", "Sequence analysis was carried out using the universal forward and reverse primers, and T7 sequencing kit from Pharmacia Biotech, (St. Albans, Herts, UK).", "The sequence of the PCR product is shown in SEQ ID No. 1. [0104] [0104] 2 .", "2 Cloning [0105] Screening of the AS019 λ Zap Express™ library was carried out according to the λ Zap Express™ system protocol, (Stratagene, 11011 North Torrey Pines Rd.", ", La Jolla, Calif.", "92037).", "Southern Blot analysis was then carried out on isolated clones.", "Southern transfer of DNA was as described in the Schleicher and Schuell protocols manual employing Nytran™ as membrane (,,Nytran, Modified Nylon `66 Membrane Filters”", "(March 1987), Schleicher and Schuell, Dassel, Germany).", "Double stranded DNA fragments, generated using the same primers and optimal PCR conditions as described above, were radio-labeled with α- 32 P-dCTP using the Multiprime™ DNA labeling kit from Amersham Life Science (Amersham Pharmacia Biotech UK Limited, Little Chalfont, Buckinghamshire, UK) according to the manufacturers instructions.", "Prehybridization, hybridization and washing conditions were as described in the Schleicher and Schuell protocols manual.", "Autoradiography was carried out according to the procedure outlined in the handbook of Sambrook et al.", "using AgFa Curix RPIL film.", "Thus several gnd clones were identified.", "Plasmid DNA was isolated from one of the clones, designated pBGNA (FIG.", "3) and chosen for further analysis.", "[0106] 2.3 Sequencing [0107] The Sanger Dideoxy chain termination method of Sanger et al.", "(Proceedings of the National Academy of Sciences USA 74, 5463-5467 (1977)) was used to sequence the cloned insert of pBGNA.", "The method was applied using the T7 sequencing kit and α- 35 S-dCTP from Pharmacia Biotech (St. Albans, Herts, UK).", "Samples were electrophoresed for 3-8 hours on 6% polyacrylamide/urea gels in TBE buffer at a constant current of 50 mA, according to the Pharmacia cloning and sequencing instructions manual (,, T7 Sequencing™ Kit”,ref.", "XY-010-00-19, Pharmacia Biotech, 1994).", "Sequence analysis was carried out using internal primers designed from the sequence known of the internal gnd PCR product (SEQ ID NO 1) allowing the entire gnd gene sequence to be deduced.", "The sequences of the internal primers were as follows: Internal primer 1: 5′ GGT GGA TGC TGA AAC CG 3′ (SEQ ID NO 9) Internal primer 2: 5′ GCT GCA TGC CTG CTG CG 3′ (SEQ ID NO 10) Internal primer 3: 5′ TTG TTG CTT ACG CAC AG 3′ (SEQ ID NO 11) Internal primer 4: 5′ TCG TAG GAC TTT GCT GG 3′ (SEQ ID NO 12) [0108] Sequences obtained were analyzed using the DNA Strider program, (Marck (1988), Nucleic Acids Research 16: 1829-1836), version 1.0 on an Apple Macintosh computer.", "This program allowed for analyses such as restriction site usage, open reading frame analysis and codon usage determination.", "Searches between DNA sequences obtained and those in EMBL and Genbank databases were performed using the BLAST program (Altschul et al.", ", (1997), Nucleic Acids Research 25: 3389-3402).", "DNA and protein sequences were aligned using the Clustal V and Clustal W programs (Higgins and Sharp, 1988 Gene 73: 237-244).", "[0109] The sequence thus obtained is shown in SEQ ID NO 2.", "The analysis of the nucleotide sequence obtained revealed an open reading frame of 1377 base pairs which was designated as gnd gene.", "It codes for a protein of 459 amino acids shown in SEQ ID NO 3.", "EXAMPLE 3 Preparation of the Shuttle Vector pEC-T18mob2 [0110] The E. coli - C. glutamicum shuttle vector pEC-T18mob2 was constructed according to the prior art.", "The vector contains the replication region, rep, of the plasmid pGA1 including the replication effector, per (U.S. Pat. No. 5,175,108;", "Nesvera et al.", ", Journal of Bacteriology 179, 1525-1532 (1997)), the tetracycline resistance-imparting tetA(Z) gene of the plasmid, pAG1 (U.S. Pat. No. 5,158,891;", "gene library entry at the National Center for Biotechnology Information (NCBI, Bethesda, Md.", ", USA) with accession number AF121000), the replication region, oriV, of the plasmid pMB1 (Sutcliffe, Cold Spring Harbor Symposium on Quantitative Biology 43, 77-90 (1979)), the lacZ gene fragment including the lac promoter and a multiple cloning site (mcs) (Norrander et al.", "Gene 26, 101-106 (1983)) and the mob region of the plasmid RP4 (Simon et al.", ",(1983) Bio/Technology 1:784-791).", "[0111] The vector constructed was transformed in the E. coli strain DH5α (Hanahan, In: DNA cloning.", "A practical approach.", "Vol. I. IRL-Press, Oxford, Washington D.C., USA, 1985).", "Selection for plasmid-carrying cells was made by plating out the transformation batch on LB agar (Sambrook et al.", ", Molecular cloning: a laboratory manual.", "2 nd Ed.", "Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., USA, 1989), which had been supplemented with 5 mg/l tetracycline.", "Plasmid DNA was isolated from a transformant with the aid of the QIAprep Spin Miniprep Kit from Qiagen and checked by restriction with the restriction enzyme EcoRI and HindIII subsequent agarose gel electrophoresis (0.8%).", "The plasmid was called pEC-T18mob2 and is shown in FIG. 1. It is deposited in the form of the strain Escherichia coli K-12 strain DH5α/pEC-T18mob2 at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) as DSM 13244.", "EXAMPLE 4 Cloning of the gnd Gene into the E. coli - C. glutamicum Shuttle Vector pEC-T18mob2 [0112] PCR was used to amplify DNA fragments containing the entire gnd gene of C. glutamicum and flanking upstream and downstream regions using pBGNA as template.", "PCR reactions were carried out using oligonucleotide primers designed from SEQ ID NO 2.", "The primers used were: gnd fwd.", "primer: 5′ ACT CTA GTC GGC CTA AAA TGG 3′ (SEQ ID NO 13) gnd rev.", "primer: 5′ CAC ACA GGA AAC AGA TAT GAC 3′.", "(SEQ ID NO 14) [0113] PCR parameters were as follows: [0114] 35 cycles [0115] 95° C. for 6 minutes [0116] 94° C. for 1 minute [0117] 50° C. for 1 minute [0118] 72° C. for 45 seconds [0119] 1 mM MgCl 2 [0120] approx.", "150-200 ng pBGNA-DNA as template.", "[0121] The PCR product obtained was cloned into the commercially available pGEM-T vector purchased from Promega Corp.", "(pGEM-T Easy Vector System 1, cat.", "no. A1360, Promega UK, Southampton) using E. coli strain JM109 (Yanisch-Perron et al.", "Gene, 33: 103-119 (1985)) as a host.", "The entire gnd gene was subsequently isolated from the pGEM T-vector on an EcoRI fragment and cloned into the lacZ EcoRI site of the E. coli - C. glutamicum shuttle vector pEC-T18mob2 (FIG.", "1), and designated pECgnd (FIG.", "2).", "Restriction enzyme analysis with AccI (Boehringer Mannheim GmbH, Germany) revealed the correct orientation (i.e., downstream the lac-Promotor) of the gnd gene in the lacZα gene of pEC-T18mob2.", "EXAMPLE 5 Preparation of Amino Acid Producers with Amplified 6-phosphogluconate Dehydrogenase [0122] Plasmid pECgnd from Example 3 was electroporated by the electroporation method of Tauch et al.", "(FEMS Microbiological Letters, 123:343-347 (1994)) in the strains Corynebacterium glutamicum DSM 5399 and DSM 5714.", "The strain DSM 5399 is a threonine producer described in EP-B-0358940.", "The strain DSM 5714 is a lysine producer described in EP-B-0435132.", "Selection of transformants was carried out by plating out the electroporation batch on LB agar (Sambrook et al.", ", Molecular cloning: a laboratory manual.", "2 nd Ed.", "Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989), which had been supplemented with 25 mg/l kanamycin.", "The strains DSM5399/pECgnd and DSM5714/pECgnd were formed in this manner.", "EXAMPLE 6 Preparation of Threonine [0123] The C. glutamicum strain DSM5399/pECgnd obtained in Example 5 was cultured in a nutrient medium suitable for the production of threonine and the threonine content in the culture supernatant was determined.", "For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l)) for 24 hours at 33° C. Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask).", "Brain-heart broth (Merck, Darmstadt, Germany) was used as the medium for the preculture.", "Tetracycline (5 mg/l) was added to this medium.", "The preculture was incubated for 24 hours at 33° C. at 240 rpm on a shaking machine.", "A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.1.", "The medium MM-threonine was used for the main culture.", "Medium MM-threonine CSL 5 g/l MOPS 20 g/l Glucose(autoclaved separately) 50 g/l Salts: (NH 4 ) 2 SO 4 25 g/l KH 2 PO 4 0.1 g/l MgSO 4 * 7 H 2 O 1.0 g/l CaCl 2 * 2 H 2 O 10 mg/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 5.0 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l CaCO 3 25 g/l [0124] The CSL (corn steep liquor), MOPS (morpholinopropanesulfonic acid) and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved.", "The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state.", "Culturing is carried out in a 10 ml volume in a 100 ml conical flask with baffles.", "Tetracycline (5 mg/l) was added.", "Culturing was carried out at 33° C. and 80% atmospheric humidity.", "After 48 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, Munich).", "The concentration of threonine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivation with ninhydrin detection.", "The result of the experiment is shown in Table 1.", "TABLE 1 OD L-Threonin Strain (660 nm) g/l DSM5399/pECgnd 11.9 1.29 DSM5399 11.8 0.33 EXAMPLE 7 Preparation of Lysine [0125] The C. glutamicum strain DSM5714/pECgnd obtained in Example 5 was cultured in a nutrient medium suitable for the production of lysine and the lysine content in the culture supernatant was determined.", "For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l)) for 24 hours at 33° C. Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask).", "The complete medium Cg III was used as the medium for the preculture.", "Medium Cg III NaCl 2.5 g/l Bacto-Peptone 10 g/l Bacto-Yeast extract 10 g/l Glucose (autoclaved separately) 2% (w/v) [0126] Tetracycline (5 mg/l) was added to this medium.", "The preculture was incubated for 24 hours at 33° C. at 240 rpm on a shaking machine.", "A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.05.", "Medium MM was used for the main culture.", "Medium MM CSL (corn steep liquor) 5 g/l MOPS (morpholinopropanesulfonic acid) 20 g/l Glucose (autoclaved separately) 50 g/l (NH 4 ) 2 SO 4 KH 2 PO 4 25 g/l MgSO 4 * 7 H 2 O 0.1 g/l CaCl 2 * 2 H 2 O 1.0 g/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 10 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l L-Leucine (sterile-filtered) 0.1 g/l CaCO 3 25 g/l [0127] The CSL, MOPS and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved.", "The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state.", "Culturing was carried out in a 10 ml volume in a 100 ml conical flask with baffles.", "Tetracycline (5 mg/l) was added.", "Culturing was carried out at 33° C. and 80% atmospheric humidity.", "[0128] After 48 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, München).", "The amount of lysine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivation with ninhydrin detection.", "The result of the experiment is shown in Table 2.", "TABLE 2 OD Lysine HCl Strain (660 nm) g/l DSM5715/pECgnd 7.7 14.7 DSM5715 7.1 13.7 EXAMPLE 8 Preparation of a Genomic Cosmid Gene Library from Corynebacterium glutamicum ATCC 13032 [0129] Chromosomal DNA from Corynebacterium glutamicum ATCC 13032 was isolated as described by Tauch et al.", ", (1995, Plasmid 33:168-179), and partly cleaved with the restriction enzyme Sau3AI (Amersham Pharmacia, Freiburg, Germany, Product Description Sau3AI, Code no. 27-0913-O 2 ).", "The DNA fragments were dephosphorylated with shrimp alkaline phosphatase (Roche Molecular Biochemicals, Mannheim, Germany, Product Description SAP, Code no. 1758250).", "The DNA of the cosmid vector SuperCos1 (Wahl et al.", "(1987) Proceedings of the National Academy of Sciences USA 84:2160-2164), obtained from Stratagene (La Jolla, USA, Product Description SuperCos1 Cosmid Vektor Kit, Code no. 251301) was cleaved with the restriction enzyme XbaI (Amersham Pharmacia, Freiburg, Germany, Product Description XbaI, Code no. 27-0948-O 2 ) and likewise dephosphorylated with shrimp alkaline phosphatase.", "[0130] The cosmid DNA was then cleaved with the restriction enzyme BamHI (Amersham Pharmacia, Freiburg, Germany, Product Description BamHI, Code no. 27-0868-04).", "The cosmid DNA treated in this manner was mixed with the treated ATCC13032 DNA and the batch was treated with T4 DNA ligase (Amersham Pharmacia, Freiburg, Germany, Product Description T4-DNA-Ligase, Code no[.", "].27-0870-04).", "The ligation mixture was then packed in phages with the aid of Gigapack II XL Packing Extracts (Stratagene, La Jolla, USA, Product Description Gigapack II XL Packing Extract, Code no. 200217).", "For infection of the E. coli strain NM554 (Raleigh et al.", "1988, Nucleic Acid Research 16:1563-1575) the cells were taken up in 10 mM MgSO 4 and mixed with an aliquot of the phage suspension.", "The infection and titering of the cosmid library were carried out as described by Sambrook et al.", "(1989, Molecular Cloning: A laboratory Manual, Cold Spring Harbor), the cells being plated out on LB agar (Lennox, 1955, Virology 1:190)+100 μg/ml ampicillin.", "After incubation overnight at 37° C., recombinant individual clones were selected.", "EXAMPLE 9 Isolation and Sequencing of the poxB Gene [0131] The cosmid DNA of an individual colony (Example 8) was isolated with the Qiaprep Spin Miniprep Kit (Product No. 27106, Qiagen, Hilden, Germany) in accordance with the manufacturer's instructions and partly cleaved with the restriction enzyme Sau3AI (Amersham Pharmacia, Freiburg, Germany, Product Description Sau3AI, Product No. 27-0913-O 2 ).", "The DNA fragments were dephosphorylated with shrimp alkaline phosphatase (Roche Molecular Biochemicals, Mannheim, Germany, Product Description SAP, Product No. 1758250).", "After separation by gel electrophoresis, the cosmid fragments in the size range of 1500 to 2000 bp were isolated with the QiaExII Gel Extraction Kit (Product No. 20021, Qiagen, Hilden, Germany).", "The DNA of the sequencing vector pZero-1, obtained from Invitrogen (Groningen, Holland, Product Description Zero Background Cloning Kit, Product No. K2500-01) was cleaved with the restriction enzyme BamHI (Amersham Pharmacia, Freiburg, Germany, Product Description BamHI, Product No. 27-0868-04).", "[0132] The ligation of the cosmid fragments in the sequencing vector pZero-1 was carried out as described by Sambrook et al.", "(1989, Molecular Cloning: A laboratory Manual, Cold Spring Harbor), the DNA mixture being incubated overnight with T4 ligase (Pharmacia Biotech, Freiburg, Germany).", "This ligation mixture was then electroporated (Tauch et al.", "1994, FEMS Microbiol Letters, 123:343-7) into the E. coli strain DH5αMCR (Grant, 1990, Proceedings of the National Academy of Sciences U.S.A., 87:4645-4649) and plated out on LB agar (Lennox, 1955, Virology, 1:190) with 50 μg/ml zeocin.", "The plasmid preparation of the recombinant clones was carried out with Biorobot 9600 (Product No. 900200, Qiagen, Hilden, Germany).", "The sequencing was carried out by the dideoxy chain-stopping method of Sanger et al.", "(1977, Proceedings of the National Academies of Sciences U.S.A., 74:5463-5467) with modifications according to Zimmermann et al.", "(1990, Nucleic Acids Research, 18:1067).", "The “RR dRhodamin Terminator Cycle Sequencing Kit”", "from PE Applied Biosystems(Product No. 403044, Weiterstadt, Germany) was used.", "The separation by gel electrophoresis and analysis of the sequencing reaction were carried out in a “Rotiphoresis NF Acrylamide/Bisacrylamide”", "Gel (29:1) (Product No. A124.1, Roth, Karlsruhe, Germany) with the “ABI Prism 377”", "sequencer from PE Applied Biosystems (Weiterstadt, Germany).", "[0133] The raw sequence data obtained were then processed using the Staden program package (1986, Nucleic Acids Research, 14:217-231) version 97-0.", "The individual sequences of the pZero1 derivatives were assembled to a continuous contig.", "The computer-assisted coding region analysis were prepared with the XNIP program (Staden, 1986, Nucleic Acids Research 14:217-231).", "Further analyses were carried out with the “BLAST search program”", "(Altschul et al.", ", 1997, Nucleic Acids Research 25:3389-3402), against the non-redundant databank of the “National Center for Biotechnology Information”", "(NCBI, Bethesda, Md.", ", USA).", "[0134] The resulting nucleotide sequence is shown in SEQ ID No. 4. Analysis of the nucleotide sequence showed an open reading frame of 1737 base pairs, which was called the poxB gene.", "The poxB gene codes for a polypeptide of 579 amino acids (SEQ ID NO.", "5).", "EXAMPLE 10 Preparation of an Integration Vector for Integration Mutagenesis of the poxB Gene [0135] From the strain ATCC 13032, chromosomal DNA was isolated by the method of Eikmanns et al.", "(Microbiology 140: 1817-1828 (1994)).", "On the basis of the sequence of the poxB gene known for C. glutamicum from Example 9, the following oligonucleotides were chosen for the polymerase chain reaction: poxBint1: 5′ TGC GAG ATG GTG AAT GGT GG 3′ (SEQ ID NO 15) poxBint2: 5′ GCA TGA GGC AAC GCA TTA GC 3′ (SEQ ID NO 16) [0136] The primers shown were synthesized by MWG Biotech (Ebersberg, Germany) and the PCR reaction was carried out by the standard PCR method of Innis et al.", "(PCR protocols.", "A guide to methods and applications, 1990, Academic Press) with Pwo-Polymerase from Boehringer.", "With the aid of the polymerase chain reaction, a DNA fragment approx.", "0.9 kb in size was isolated, this carrying an internal fragment of the poxB gene and being shown in SEQ ID No:6.", "[0137] The amplified DNA fragment was ligated with the TOPO TA Cloning Kit from Invitrogen Corporation (Carlsbad, Calif.", ", USA;", "Catalogue Number K4500-01) in the vector pCR2.1-TOPO (Mead at al.", "(1991) Bio/Technology 9:657-663).", "The E. coli Stamm DH5α was then electroporated with the ligation batch (Hanahan, In: DNA cloning.", "A practical approach.", "Vol. 1. IRL-Press, Oxford, Washington D.C., USA, 1985).", "Selection for plasmid-carrying cells was made by plating out the transformation batch on LB agar (Sambrook et al.", ", Molecular cloning: a laboratory manual.", "2 nd Ed.", "Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989), which had been supplemented with 25 mg/l kanamycin.", "Plasmid DNA was isolated from a transformant with the aid of the QIAprep Spin Miniprep Kit from Qiagen and checked by restriction with the restriction enzyme EcoRI and subsequent agarose gel electrophoresis (0.8%).", "The plasmid was called pCR2.1poxBint (FIG.", "4).", "[0138] Plasmid pCR2.1poxBint has been deposited in the form of the strain Escherichia coli DH5α/pCR2.1poxBint as DSM 13114 at the Deutsche Sammlung für Mikroorganismen und Zellkulturen (DSMZ=German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany) in accordance with the Budapest Treaty.", "EXAMPLE 11 Integration Mutagenesis of the poxB Gene in the Lysine Producer DSM 5715 [0139] The vector pCR2.1poxBint mentioned in Example 10 was electroporated by the electroporation method of Tauch et al.", "(FEMS Microbiological Letters, 123:343-347 (1994)) in Corynebacterium glutamicum DSM 5715.", "Strain DSM 5715 is an AEC-resistant lysine producer.", "The vector pCR2.1poxBint cannot replicate independently in DSM5715 and is retained only if it has integrated into the cell's chromosome.", "Selection of clones with pCR2.1poxBint integrated into the chromosome was carried out by plating out the electroporation batch on LB agar (Sambrook et al.", ", Molecular Cloning: A Laboratory Manual.", "2 nd ed.", ", Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.), which had been supplemented with 15 mg/l kanamycin.", "For detection of the integration, the poxBint fragment was labeled with the Dig hybridization kit from Boehringer by the method of “The DIG System Users Guide for Filter Hybridization”", "of Boehringer Mannheim GmbH (Mannheim, Germany, 1993).", "Chromosomal DNA of a potential integrant was isolated by the method of Eikmanns et al.", "(Microbiology 140: 1817-1828 (1994)) and in each case cleaved with the restriction enzymes SalI, SacI and HindIII.", "The fragments formed were separated by agarose gel electrophoresis and hybridized at 68° C. with the Dig hybridization kit from Boehringer.", "The plasmid pCR2.1poxBint mentioned in Example 9 had been inserted into the chromosome of DSM5715 within the chromosomal poxB gene.", "The strain was called DSM5715::pCR2.1poxBint.", "EXAMPLE 12 Effect of Over-Expression of the gnd Gene with Simultaneous Elimination of the poxB Gene on the Preparation of Lysine [0140] 12.1 Preparation of the Strain DSM5715::pCR2.1poxBint/pECgnd [0141] The strain DSM5715::pCR2.1poxBint was transformed with the plasmid pECgnd using the electroporation method described by Liebl et al.", ", (FEMS Microbiology Letters, 53:299-303 (1989)).", "Selection of the transformants took place on LBHIS agar comprising 18.5 μl brain-heart infusion broth, 0.5 M sorbitol, 5 g/l Bacto-tryptone, 2.5 g/l Bacto-yeast extract, 5 g/l NaCl and 18 g/l Bacto-agar, which had been supplemented with 5 mg/l tetracycline and 25 mg/l kanamycin.", "Incubation was carried out for 2 days at 33° C. [0142] Plasmid DNA was isolated in each case from a transformant by conventional methods (Peters-Wendisch et al.", ", 1998, Microbiology 144, 915-927), cleaved with the restriction endonuclease AccI, and the plasmid was checked by subsequent agarose gel electrophoresis.", "The strain obtained in this way was called DSM5715:pCR2.1poxBint/pECgnd.", "[0143] 12.2 Preparation of L-lysine [0144] The C. glutamicum strain DSM5715::pCR2.1poxBint/pECgnd obtained in Example 12.1 was cultured in a nutrient medium suitable for the production of lysine and the lysine content in the culture supernatant was determined.", "For this, the strain was first incubated on an agar plate with the corresponding antibiotic (brain-heart agar with tetracycline (5 mg/l) and kanamycin (25 mg/l)) for 24 hours at 33° C. The cultures of the comparison strains were supplemented according to their resistance to antibiotics.", "Starting from this agar plate culture, a preculture was seeded (10 ml medium in a 100 ml conical flask).", "The complete medium CgIII was used as the medium for the preculture.", "Medium Cg III NaCl 2.5 g/l Bacto-Peptone 10 g/l Bacto-Yeast extract 10 g/l Glucose (autoclaved separately) 2% (w/v) [0145] Tetracycline (5 mg/l) and kanamycin (25 mg/l) were added to this.", "The preculture was incubated for 16 hours at 33° C. at 240 rpm on a shaking machine.", "A main culture was seeded from this preculture such that the initial OD (660 nm) of the main culture was 0.1.", "Medium MM was used for the main culture.", "Medium MM CSL (corn steep liquor) 5 g/l MOPS (morpholinopropanesulfonic acid) 20 g/l Glucose (autoclaved separately) 58 g/l (NH 4 ) 2 SO 4 25 g/l KH 2 PO 4 0.1 g/l MgSO 4 * 7 H 2 O 1.0 g/l CaCl 2 * 2 H 2 O 10 mg/l FeSO 4 * 7 H 2 O 10 mg/l MnSO 4 * H 2 O 5.0 mg/l Biotin (sterile-filtered) 0.3 mg/l Thiamine * HCl (sterile-filtered) 0.2 mg/l L-Leucine (sterile-filtered) 0.1 g/l CaCO 3 25 g/l [0146] The CSL, MOPS and the salt solution were brought to pH 7 with aqueous ammonia and autoclaved.", "The sterile substrate and vitamin solutions were then added, as well as the CaCO 3 autoclaved in the dry state.", "Culturing was carried out in a 10 ml volume in a 100 ml conical flask with baffles.", "Tetracycline (5 mg/l) and kanamycin (25 mg/l) were added.", "Culturing was carried out at 33° C. and 80% atmospheric humidity.", "[0147] After 72 hours, the OD was determined at a measurement wavelength of 660 nm with a Biomek 1000 (Beckmann Instruments GmbH, München).", "The amount of lysine formed was determined with an amino acid analyzer from Eppendorf-BioTronik (Hamburg, Germany) by ion exchange chromatography and post-column derivatization with ninhydrin detection.", "The result of the experiment is shown in Table 3.", "TABLE 3 OD L-Lysine HCl Strain (660 nm) g/l DSM5715 10.8 16.0 DSM5715/pECgnd 7.6 16.5 DSM5715::pCR2.1poxBint 7.1 16.7 DSM5715::pCR2.1poxBint/ 7.2 17.1 pECgnd [0148] [0148] 1 16 1 252 DNA Corynebacterium glutamicum 1 atggtccaca acggcatcga gtacgccgac atgcaggtca tcggcgaggc ataccacctt 60 ctgccctacg cagcaggcat gcagccagct gaaatcgctg aggttttcaa ggaatggaac 120 gcaggcgacc tggattccta cctcatcgaa atcaccgcag aggttctctc ccaggtggat 180 gctgaaaccg gcaagccact aatcgacgtc atcgttgacg ctgcaggtca gaagggcacc 240 ggcaagtgga ct 252 2 2335 DNA Corynebacterium glutamicum CDS (474)..", "(1850) gnd 2 ttgttcggcc acgatgacac cggagctcac agcagaaatg aagtcggtgt tgttgttgat 60 gccgacgacc atttttccag gggcggaaat catgctggcg actgatccag tggattcggc 120 gatggcggcg tagacaccac cgttgaccaa gcccaccact tgcaggtgct tggatgccac 180 gtgaagttcg ctgaccaccc ggccgggctc gatggtggtg tagcgcagcc ccagattgcg 240 gtcgaggcca taattggcgt tgttgagtgc ttcaagttcg tctgtggtta aagctctggt 300 ggcggcaagt tctgcaagcg aaagcagatc ttggggttga tcatcgcggg aagtcataat 360 taattactct agtcggccta aaatggttgg attttcacct cctgtgacct ggtaaaatcg 420 ccactacccc caaatggtca caccttttag gccgattttg ctgacaccgg gct atg 476 Met 1 ccg tca agt acg atc aat aac atg act aat gga gat aat ctc gca cag 524 Pro Ser Ser Thr Ile Asn Asn Met Thr Asn Gly Asp Asn Leu Ala Gln 5 10 15 atc ggc gtt gta ggc cta gca gta atg ggc tca aac ctc gcc cgc aac 572 Ile Gly Val Val Gly Leu Ala Val Met Gly Ser Asn Leu Ala Arg Asn 20 25 30 ttc gcc cgc aac ggc aac act gtc gct gtc tac aac cgc agc act gac 620 Phe Ala Arg Asn Gly Asn Thr Val Ala Val Tyr Asn Arg Ser Thr Asp 35 40 45 aaa acc gac aag ctc atc gcc gat cac ggc tcc gaa ggc aac ttc atc 668 Lys Thr Asp Lys Leu Ile Ala Asp His Gly Ser Glu Gly Asn Phe Ile 50 55 60 65 cct tct gca acc gtc gaa gag ttc gta gca tcc ctg gaa aag cca cgc 716 Pro Ser Ala Thr Val Glu Glu Phe Val Ala Ser Leu Glu Lys Pro Arg 70 75 80 cgc gcc atc atc atg gtt cag gct ggt aac gcc acc gac gca gtc atc 764 Arg Ala Ile Ile Met Val Gln Ala Gly Asn Ala Thr Asp Ala Val Ile 85 90 95 aac cag ctg gca gat gcc atg gac gaa ggc gac atc atc atc gac ggc 812 Asn Gln Leu Ala Asp Ala Met Asp Glu Gly Asp Ile Ile Ile Asp Gly 100 105 110 ggc aac gcc ctc tac acc gac acc att cgt cgc gag aag gaa atc tcc 860 Gly Asn Ala Leu Tyr Thr Asp Thr Ile Arg Arg Glu Lys Glu Ile Ser 115 120 125 gca cgc ggt ctc cac ttc gtc ggt gct ggt atc tcc ggc ggc gaa gaa 908 Ala Arg Gly Leu His Phe Val Gly Ala Gly Ile Ser Gly Gly Glu Glu 130 135 140 145 ggc gca ctc aac ggc cca tcc atc atg cct ggt ggc cca gca aag tcc 956 Gly Ala Leu Asn Gly Pro Ser Ile Met Pro Gly Gly Pro Ala Lys Ser 150 155 160 tac gag tcc ctc gga cca ctg ctt gag tcc atc gct gcc aac gtt gac 1004 Tyr Glu Ser Leu Gly Pro Leu Leu Glu Ser Ile Ala Ala Asn Val Asp 165 170 175 ggc acc cca tgt gtc acc cac atc ggc cca gac ggc gcc ggc cac ttc 1052 Gly Thr Pro Cys Val Thr His Ile Gly Pro Asp Gly Ala Gly His Phe 180 185 190 gtc aag atg gtc cac aac ggc atc gag tac gcc gac atg cag gtc atc 1100 Val Lys Met Val His Asn Gly Ile Glu Tyr Ala Asp Met Gln Val Ile 195 200 205 ggc gag gca tac cac ctt ctg ccc tac gca gca ggc atg cag cca gct 1148 Gly Glu Ala Tyr His Leu Leu Pro Tyr Ala Ala Gly Met Gln Pro Ala 210 215 220 225 gaa atc gct gag gtt ttc aag gaa tgg aac gca ggc gac ctg gat tcc 1196 Glu Ile Ala Glu Val Phe Lys Glu Trp Asn Ala Gly Asp Leu Asp Ser 230 235 240 tac ctc atc gaa atc acc gca gag gtt ctc tcc cag gtg gat gct gaa 1244 Tyr Leu Ile Glu Ile Thr Ala Glu Val Leu Ser Gln Val Asp Ala Glu 245 250 255 acc ggc aag cca cta atc gac gtc atc gtt gac gct gca ggt cag aag 1292 Thr Gly Lys Pro Leu Ile Asp Val Ile Val Asp Ala Ala Gly Gln Lys 260 265 270 ggc acc ggc aag tgg act gtc aag gct gct ctt gat ctg ggt att gct 1340 Gly Thr Gly Lys Trp Thr Val Lys Ala Ala Leu Asp Leu Gly Ile Ala 275 280 285 acc acc ggc atc ggc gaa cgt gtt ttc gca cgt gca ctc tcc ggc gca 1388 Thr Thr Gly Ile Gly Glu Arg Val Phe Ala Arg Ala Leu Ser Gly Ala 290 295 300 305 acc agc cag cgc gct gca gca cag ggc aac cta cct gca ggt gtc ctc 1436 Thr Ser Gln Arg Ala Ala Ala Gln Gly Asn Leu Pro Ala Gly Val Leu 310 315 320 acc gat ctg gaa gca ctt ggc gtg gac aag gca cag ttc gtc gaa gga 1484 Thr Asp Leu Glu Ala Leu Gly Val Asp Lys Ala Gln Phe Val Glu Gly 325 330 335 ctt cgc cgt gca ctg tac gca tcc aag ctt gtt gct tac gca cag ggc 1532 Leu Arg Arg Ala Leu Tyr Ala Ser Lys Leu Val Ala Tyr Ala Gln Gly 340 345 350 ttc gac gag atc aag gct ggc tcc gac gag aac aac tgg gac gtt gac 1580 Phe Asp Glu Ile Lys Ala Gly Ser Asp Glu Asn Asn Trp Asp Val Asp 355 360 365 cct cgc gac ctc gct acc atc tgg cgc ggc ggc tgc atc att cgc gct 1628 Pro Arg Asp Leu Ala Thr Ile Trp Arg Gly Gly Cys Ile Ile Arg Ala 370 375 380 385 aag ttc ctc aac cgc atc gtc gaa gca tac gat gca aac gct gaa ctt 1676 Lys Phe Leu Asn Arg Ile Val Glu Ala Tyr Asp Ala Asn Ala Glu Leu 390 395 400 gag tcc ctg ctg ctc gat cct tac ttc aag agc gag ctc ggc gac ctc 1724 Glu Ser Leu Leu Leu Asp Pro Tyr Phe Lys Ser Glu Leu Gly Asp Leu 405 410 415 atc gat tca tgg cgt cgc gtg att gtc acc gcc acc cag ctt ggc ctg 1772 Ile Asp Ser Trp Arg Arg Val Ile Val Thr Ala Thr Gln Leu Gly Leu 420 425 430 cca atc cca gtg ttc gct tcc tcc ctg tcc tac tac gac agc ctg cgt 1820 Pro Ile Pro Val Phe Ala Ser Ser Leu Ser Tyr Tyr Asp Ser Leu Arg 435 440 445 gca gag cgt ctg cca gca gcc ctg atc cac tagtgtcgac ctgcaggcgc 1870 Ala Glu Arg Leu Pro Ala Ala Leu Ile His 450 455 gcgagctcca gcttttgttc cctttagtga gggttaattt cgagcttggc gtaatcaagg 1930 tcatagctgt ttcctgtgtg aaattgttat ccgctcacaa ttccacacaa tatacgagcc 1990 ggaagtataa agtgtaaagc ctggggtgcc taatgagtga gctaactcac agtaattgcg 2050 gctagcggat ctgacggttc actaaaccag ctctgcttat atagacctcc caccgtacac 2110 gcctaccgcc catttgcgtc aatggggcgg agttgttacg acattttgga aagtcccgtt 2170 gattttggtg ccaaaacaaa ctcccattga cgtcaatggg gtggagactt ggaaatcccc 2230 gtgagtcaaa ccgctatcca cgcccattga tgtactgcca aaaccgcatc accatggtaa 2290 tagcgatgac taatacgtag atgtactgcc aagtaggaaa gtccc 2335 3 459 PRT Corynebacterium glutamicum 3 Met Pro Ser Ser Thr Ile Asn Asn Met Thr Asn Gly Asp Asn Leu Ala 1 5 10 15 Gln Ile Gly Val Val Gly Leu Ala Val Met Gly Ser Asn Leu Ala Arg 20 25 30 Asn Phe Ala Arg Asn Gly Asn Thr Val Ala Val Tyr Asn Arg Ser Thr 35 40 45 Asp Lys Thr Asp Lys Leu Ile Ala Asp His Gly Ser Glu Gly Asn Phe 50 55 60 Ile Pro Ser Ala Thr Val Glu Glu Phe Val Ala Ser Leu Glu Lys Pro 65 70 75 80 Arg Arg Ala Ile Ile Met Val Gln Ala Gly Asn Ala Thr Asp Ala Val 85 90 95 Ile Asn Gln Leu Ala Asp Ala Met Asp Glu Gly Asp Ile Ile Ile Asp 100 105 110 Gly Gly Asn Ala Leu Tyr Thr Asp Thr Ile Arg Arg Glu Lys Glu Ile 115 120 125 Ser Ala Arg Gly Leu His Phe Val Gly Ala Gly Ile Ser Gly Gly Glu 130 135 140 Glu Gly Ala Leu Asn Gly Pro Ser Ile Met Pro Gly Gly Pro Ala Lys 145 150 155 160 Ser Tyr Glu Ser Leu Gly Pro Leu Leu Glu Ser Ile Ala Ala Asn Val 165 170 175 Asp Gly Thr Pro Cys Val Thr His Ile Gly Pro Asp Gly Ala Gly His 180 185 190 Phe Val Lys Met Val His Asn Gly Ile Glu Tyr Ala Asp Met Gln Val 195 200 205 Ile Gly Glu Ala Tyr His Leu Leu Pro Tyr Ala Ala Gly Met Gln Pro 210 215 220 Ala Glu Ile Ala Glu Val Phe Lys Glu Trp Asn Ala Gly Asp Leu Asp 225 230 235 240 Ser Tyr Leu Ile Glu Ile Thr Ala Glu Val Leu Ser Gln Val Asp Ala 245 250 255 Glu Thr Gly Lys Pro Leu Ile Asp Val Ile Val Asp Ala Ala Gly Gln 260 265 270 Lys Gly Thr Gly Lys Trp Thr Val Lys Ala Ala Leu Asp Leu Gly Ile 275 280 285 Ala Thr Thr Gly Ile Gly Glu Arg Val Phe Ala Arg Ala Leu Ser Gly 290 295 300 Ala Thr Ser Gln Arg Ala Ala Ala Gln Gly Asn Leu Pro Ala Gly Val 305 310 315 320 Leu Thr Asp Leu Glu Ala Leu Gly Val Asp Lys Ala Gln Phe Val Glu 325 330 335 Gly Leu Arg Arg Ala Leu Tyr Ala Ser Lys Leu Val Ala Tyr Ala Gln 340 345 350 Gly Phe Asp Glu Ile Lys Ala Gly Ser Asp Glu Asn Asn Trp Asp Val 355 360 365 Asp Pro Arg Asp Leu Ala Thr Ile Trp Arg Gly Gly Cys Ile Ile Arg 370 375 380 Ala Lys Phe Leu Asn Arg Ile Val Glu Ala Tyr Asp Ala Asn Ala Glu 385 390 395 400 Leu Glu Ser Leu Leu Leu Asp Pro Tyr Phe Lys Ser Glu Leu Gly Asp 405 410 415 Leu Ile Asp Ser Trp Arg Arg Val Ile Val Thr Ala Thr Gln Leu Gly 420 425 430 Leu Pro Ile Pro Val Phe Ala Ser Ser Leu Ser Tyr Tyr Asp Ser Leu 435 440 445 Arg Ala Glu Arg Leu Pro Ala Ala Leu Ile His 450 455 4 2160 DNA Corynebacterium glutamicum CDS (327)..", "(2063) poxB 4 ttagaggcga ttctgtgagg tcactttttg tggggtcggg gtctaaattt ggccagtttt 60 cgaggcgacc agacaggcgt gcccacgatg tttaaatagg cgatcggtgg gcatctgtgt 120 ttggtttcga cgggctgaaa ccaaaccaga ctgcccagca acgacggaaa tcccaaaagt 180 gggcatccct gtttggtacc gagtacccac ccgggcctga aactccctgg caggcgggcg 240 aagcgtggca acaactggaa tttaagagca caattgaagt cgcaccaagt taggcaacac 300 aatagccata acgttgagga gttcag atg gca cac agc tac gca gaa caa tta 353 Met Ala His Ser Tyr Ala Glu Gln Leu 1 5 att gac act ttg gaa gct caa ggt gtg aag cga att tat ggt ttg gtg 401 Ile Asp Thr Leu Glu Ala Gln Gly Val Lys Arg Ile Tyr Gly Leu Val 10 15 20 25 ggt gac agc ctt aat ccg atc gtg gat gct gtc cgc caa tca gat att 449 Gly Asp Ser Leu Asn Pro Ile Val Asp Ala Val Arg Gln Ser Asp Ile 30 35 40 gag tgg gtg cac gtt cga aat gag gaa gcg gcg gcg ttt gca gcc ggt 497 Glu Trp Val His Val Arg Asn Glu Glu Ala Ala Ala Phe Ala Ala Gly 45 50 55 gcg gaa tcg ttg atc act ggg gag ctg gca gta tgt gct gct tct tgt 545 Ala Glu Ser Leu Ile Thr Gly Glu Leu Ala Val Cys Ala Ala Ser Cys 60 65 70 ggt cct gga aac aca cac ctg att cag ggt ctt tat gat tcg cat cga 593 Gly Pro Gly Asn Thr His Leu Ile Gln Gly Leu Tyr Asp Ser His Arg 75 80 85 aat ggt gcg aag gtg ttg gcc atc gct agc cat att ccg agt gcc cag 641 Asn Gly Ala Lys Val Leu Ala Ile Ala Ser His Ile Pro Ser Ala Gln 90 95 100 105 att ggt tcg acg ttc ttc cag gaa acg cat ccg gag att ttg ttt aag 689 Ile Gly Ser Thr Phe Phe Gln Glu Thr His Pro Glu Ile Leu Phe Lys 110 115 120 gaa tgc tct ggt tac tgc gag atg gtg aat ggt ggt gag cag ggt gaa 737 Glu Cys Ser Gly Tyr Cys Glu Met Val Asn Gly Gly Glu Gln Gly Glu 125 130 135 cgc att ttg cat cac gcg att cag tcc acc atg gcg ggt aaa ggt gtg 785 Arg Ile Leu His His Ala Ile Gln Ser Thr Met Ala Gly Lys Gly Val 140 145 150 tcg gtg gta gtg att cct ggt gat atc gct aag gaa gac gca ggt gac 833 Ser Val Val Val Ile Pro Gly Asp Ile Ala Lys Glu Asp Ala Gly Asp 155 160 165 ggt act tat tcc aat tcc act att tct tct ggc act cct gtg gtg ttc 881 Gly Thr Tyr Ser Asn Ser Thr Ile Ser Ser Gly Thr Pro Val Val Phe 170 175 180 185 ccg gat cct act gag gct gca gcg ctg gtg gag gcg att aac aac gct 929 Pro Asp Pro Thr Glu Ala Ala Ala Leu Val Glu Ala Ile Asn Asn Ala 190 195 200 aag tct gtc act ttg ttc tgc ggt gcg ggc gtg aag aat gct cgc gcg 977 Lys Ser Val Thr Leu Phe Cys Gly Ala Gly Val Lys Asn Ala Arg Ala 205 210 215 cag gtg ttg gag ttg gcg gag aag att aaa tca ccg atc ggg cat gcg 1025 Gln Val Leu Glu Leu Ala Glu Lys Ile Lys Ser Pro Ile Gly His Ala 220 225 230 ctg ggt ggt aag cag tac atc cag cat gag aat ccg ttt gag gtc ggc 1073 Leu Gly Gly Lys Gln Tyr Ile Gln His Glu Asn Pro Phe Glu Val Gly 235 240 245 atg tct ggc ctg ctt ggt tac ggc gcc tgc gtg gat gcg tcc aat gag 1121 Met Ser Gly Leu Leu Gly Tyr Gly Ala Cys Val Asp Ala Ser Asn Glu 250 255 260 265 gcg gat ctg ctg att cta ttg ggt acg gat ttc cct tat tct gat ttc 1169 Ala Asp Leu Leu Ile Leu Leu Gly Thr Asp Phe Pro Tyr Ser Asp Phe 270 275 280 ctt cct aaa gac aac gtt gcc cag gtg gat atc aac ggt gcg cac att 1217 Leu Pro Lys Asp Asn Val Ala Gln Val Asp Ile Asn Gly Ala His Ile 285 290 295 ggt cga cgt acc acg gtg aag tat ccg gtg acc ggt gat gtt gct gca 1265 Gly Arg Arg Thr Thr Val Lys Tyr Pro Val Thr Gly Asp Val Ala Ala 300 305 310 aca atc gaa aat att ttg cct cat gtg aag gaa aaa aca gat cgt tcc 1313 Thr Ile Glu Asn Ile Leu Pro His Val Lys Glu Lys Thr Asp Arg Ser 315 320 325 ttc ctt gat cgg atg ctc aag gca cac gag cgt aag ttg agc tcg gtg 1361 Phe Leu Asp Arg Met Leu Lys Ala His Glu Arg Lys Leu Ser Ser Val 330 335 340 345 gta gag acg tac aca cat aac gtc gag aag cat gtg cct att cac cct 1409 Val Glu Thr Tyr Thr His Asn Val Glu Lys His Val Pro Ile His Pro 350 355 360 gaa tac gtt gcc tct att ttg aac gag ctg gcg gat aag gat gcg gtg 1457 Glu Tyr Val Ala Ser Ile Leu Asn Glu Leu Ala Asp Lys Asp Ala Val 365 370 375 ttt act gtg gat acc ggc atg tgc aat gtg tgg cat gcg agg tac atc 1505 Phe Thr Val Asp Thr Gly Met Cys Asn Val Trp His Ala Arg Tyr Ile 380 385 390 gag aat ccg gag gga acg cgc gac ttt gtg ggt tca ttc cgc cac ggc 1553 Glu Asn Pro Glu Gly Thr Arg Asp Phe Val Gly Ser Phe Arg His Gly 395 400 405 acg atg gct aat gcg ttg cct cat gcg att ggt gcg caa agt gtt gat 1601 Thr Met Ala Asn Ala Leu Pro His Ala Ile Gly Ala Gln Ser Val Asp 410 415 420 425 cga aac cgc cag gtg atc gcg atg tgt ggc gat ggt ggt ttg ggc atg 1649 Arg Asn Arg Gln Val Ile Ala Met Cys Gly Asp Gly Gly Leu Gly Met 430 435 440 ctg ctg ggt gag ctt ctg acc gtt aag ctg cac caa ctt ccg ctg aag 1697 Leu Leu Gly Glu Leu Leu Thr Val Lys Leu His Gln Leu Pro Leu Lys 445 450 455 gct gtg gtg ttt aac aac agt tct ttg ggc atg gtg aag ttg gag atg 1745 Ala Val Val Phe Asn Asn Ser Ser Leu Gly Met Val Lys Leu Glu Met 460 465 470 ctc gtg gag gga cag cca gaa ttt ggt act gac cat gag gaa gtg aat 1793 Leu Val Glu Gly Gln Pro Glu Phe Gly Thr Asp His Glu Glu Val Asn 475 480 485 ttc gca gag att gcg gcg gct gcg ggt atc aaa tcg gta cgc atc acc 1841 Phe Ala Glu Ile Ala Ala Ala Ala Gly Ile Lys Ser Val Arg Ile Thr 490 495 500 505 gat ccg aag aaa gtt cgc gag cag cta gct gag gca ttg gca tat cct 1889 Asp Pro Lys Lys Val Arg Glu Gln Leu Ala Glu Ala Leu Ala Tyr Pro 510 515 520 gga cct gta ctg atc gat atc gtc acg gat cct aat gcg ctg tcg atc 1937 Gly Pro Val Leu Ile Asp Ile Val Thr Asp Pro Asn Ala Leu Ser Ile 525 530 535 cca cca acc atc acg tgg gaa cag gtc atg gga ttc agc aag gcg gcc 1985 Pro Pro Thr Ile Thr Trp Glu Gln Val Met Gly Phe Ser Lys Ala Ala 540 545 550 acc cga acc gtc ttt ggt gga gga gta gga gcg atg atc gat ctg gcc 2033 Thr Arg Thr Val Phe Gly Gly Gly Val Gly Ala Met Ile Asp Leu Ala 555 560 565 cgt tcg aac ata agg aat att cct act cca tgatgattga tacacctgct 2083 Arg Ser Asn Ile Arg Asn Ile Pro Thr Pro 570 575 gttctcattg accgcgagcg cttaactgcc aacatttcca ggatggcagc tcacgccggt 2143 gcccatgaga ttgccct 2160 5 579 PRT Corynebacterium glutamicum 5 Met Ala His Ser Tyr Ala Glu Gln Leu Ile Asp Thr Leu Glu Ala Gln 1 5 10 15 Gly Val Lys Arg Ile Tyr Gly Leu Val Gly Asp Ser Leu Asn Pro Ile 20 25 30 Val Asp Ala Val Arg Gln Ser Asp Ile Glu Trp Val His Val Arg Asn 35 40 45 Glu Glu Ala Ala Ala Phe Ala Ala Gly Ala Glu Ser Leu Ile Thr Gly 50 55 60 Glu Leu Ala Val Cys Ala Ala Ser Cys Gly Pro Gly Asn Thr His Leu 65 70 75 80 Ile Gln Gly Leu Tyr Asp Ser His Arg Asn Gly Ala Lys Val Leu Ala 85 90 95 Ile Ala Ser His Ile Pro Ser Ala Gln Ile Gly Ser Thr Phe Phe Gln 100 105 110 Glu Thr His Pro Glu Ile Leu Phe Lys Glu Cys Ser Gly Tyr Cys Glu 115 120 125 Met Val Asn Gly Gly Glu Gln Gly Glu Arg Ile Leu His His Ala Ile 130 135 140 Gln Ser Thr Met Ala Gly Lys Gly Val Ser Val Val Val Ile Pro Gly 145 150 155 160 Asp Ile Ala Lys Glu Asp Ala Gly Asp Gly Thr Tyr Ser Asn Ser Thr 165 170 175 Ile Ser Ser Gly Thr Pro Val Val Phe Pro Asp Pro Thr Glu Ala Ala 180 185 190 Ala Leu Val Glu Ala Ile Asn Asn Ala Lys Ser Val Thr Leu Phe Cys 195 200 205 Gly Ala Gly Val Lys Asn Ala Arg Ala Gln Val Leu Glu Leu Ala Glu 210 215 220 Lys Ile Lys Ser Pro Ile Gly His Ala Leu Gly Gly Lys Gln Tyr Ile 225 230 235 240 Gln His Glu Asn Pro Phe Glu Val Gly Met Ser Gly Leu Leu Gly Tyr 245 250 255 Gly Ala Cys Val Asp Ala Ser Asn Glu Ala Asp Leu Leu Ile Leu Leu 260 265 270 Gly Thr Asp Phe Pro Tyr Ser Asp Phe Leu Pro Lys Asp Asn Val Ala 275 280 285 Gln Val Asp Ile Asn Gly Ala His Ile Gly Arg Arg Thr Thr Val Lys 290 295 300 Tyr Pro Val Thr Gly Asp Val Ala Ala Thr Ile Glu Asn Ile Leu Pro 305 310 315 320 His Val Lys Glu Lys Thr Asp Arg Ser Phe Leu Asp Arg Met Leu Lys 325 330 335 Ala His Glu Arg Lys Leu Ser Ser Val Val Glu Thr Tyr Thr His Asn 340 345 350 Val Glu Lys His Val Pro Ile His Pro Glu Tyr Val Ala Ser Ile Leu 355 360 365 Asn Glu Leu Ala Asp Lys Asp Ala Val Phe Thr Val Asp Thr Gly Met 370 375 380 Cys Asn Val Trp His Ala Arg Tyr Ile Glu Asn Pro Glu Gly Thr Arg 385 390 395 400 Asp Phe Val Gly Ser Phe Arg His Gly Thr Met Ala Asn Ala Leu Pro 405 410 415 His Ala Ile Gly Ala Gln Ser Val Asp Arg Asn Arg Gln Val Ile Ala 420 425 430 Met Cys Gly Asp Gly Gly Leu Gly Met Leu Leu Gly Glu Leu Leu Thr 435 440 445 Val Lys Leu His Gln Leu Pro Leu Lys Ala Val Val Phe Asn Asn Ser 450 455 460 Ser Leu Gly Met Val Lys Leu Glu Met Leu Val Glu Gly Gln Pro Glu 465 470 475 480 Phe Gly Thr Asp His Glu Glu Val Asn Phe Ala Glu Ile Ala Ala Ala 485 490 495 Ala Gly Ile Lys Ser Val Arg Ile Thr Asp Pro Lys Lys Val Arg Glu 500 505 510 Gln Leu Ala Glu Ala Leu Ala Tyr Pro Gly Pro Val Leu Ile Asp Ile 515 520 525 Val Thr Asp Pro Asn Ala Leu Ser Ile Pro Pro Thr Ile Thr Trp Glu 530 535 540 Gln Val Met Gly Phe Ser Lys Ala Ala Thr Arg Thr Val Phe Gly Gly 545 550 555 560 Gly Val Gly Ala Met Ile Asp Leu Ala Arg Ser Asn Ile Arg Asn Ile 565 570 575 Pro Thr Pro 6 875 DNA Corynebacterium glutamicum 6 tgcgagatgg tgaatggtgg tgagcagggt gaacgcattt tgcatcacgc gattcagtcc 60 accatggcgg gtaaaggtgt gtcggtggta gtgattcctg gtgatatcgc taaggaagac 120 gcaggtgacg gtacttattc caattccact atttcttctg gcactcctgt ggtgttcccg 180 gatcctactg aggctgcagc gctggtggag gcgattaaca acgctaagtc tgtcactttg 240 ttctgcggtg cgggcgtgaa gaatgctcgc gcgcaggtgt tggagttggc ggagaagatt 300 aaatcaccga tcgggcatgc gctgggtggt aagcagtaca tccagcatga gaatccgttt 360 gaggtcggca tgtctggcct gcttggttac ggcgcctgcg tggatgcgtc caatgaggcg 420 gatctgctga ttctattggg tacggatttc ccttattctg atttccttcc taaagacaac 480 gttgcccagg tggatatcaa cggtgcgcac attggtcgac gtaccacggt gaagtatccg 540 gtgaccggtg atgttgctgc aacaatcgaa aatattttgc ctcatgtgaa ggaaaaaaca 600 gatcgttcct tccttgatcg gatgctcaag gcacacgagc gtaagttgag ctcggtggta 660 gagacgtaca cacataacgt cgagaagcat gtgcctattc accctgaata cgttgcctct 720 attttgaacg agctggcgga taaggatgcg gtgtttactg tggataccgg catgtgcaat 780 gtgtggcatg cgaggtacat cgagaatccg gagggaacgc gcgactttgt gggttcattc 840 cgccacggca cgatggctaa tgcgttgcct catgc 875 7 23 DNA Artificial sequence Description of artificial sequence Primer gnd1 7 atggtkcaca cyggyatyga rta 23 8 21 DNA Artificial sequence Description of artificial sequence Primer gnd2 8 rgtccayttr ccrgtrccyt t 21 9 17 DNA Artificial sequence Description of artificial sequence Internal primer 1 9 ggtggatgct gaaaccg 17 10 17 DNA Artificial sequence Description of artificial sequence Internal primer 2 10 gctgcatgcc tgctgcg 17 11 17 DNA Artificial sequence Description of artificial sequence Internal primer 3 11 ttgttgctta cgcacag 17 12 17 DNA Artificial sequence Description of artificial sequence Internal primer 4 12 tcgtaggact ttgctgg 17 13 21 DNA Artificial sequence Description of artificial sequence gnd fwd.", "primer 13 actctagtcg gcctaaaatg g 21 14 21 DNA Artificial sequence Description of artificial sequence gnd rev.", "primer 14 cacacaggaa acagatatga c 21 15 20 DNA Artificial sequence Description of artificial sequence Primer poxBint1 15 tgcgagatgg tgaatggtgg 20 16 20 DNA Artificial sequence Description of artificial sequence Primer poxBint2 16 gcatgaggca acgcattagc 20" ]
CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 60/733,703 filed Nov. 4, 2005, which is incorporated by reference as if fully set forth. FIELD OF INVENTION [0002] The present invention relates to wireless communication systems. More particularly, the present invention relates to mapping of Third Generation Partnership Project (3GPP) service primitives to media independent handover (MIH) event services as defined within the IEEE 802.21 standard. BACKGROUND [0003] The IEEE 802.21 standard relates to mechanisms and procedures that aid in the execution and management of inter-system handovers. Under the IEEE 802.21 standard, three main services can be accessed by mobility management (MM) applications in order to aid in the management of handover operations and system discovery and system selection. These three services include an event service, an information service and a command service, which are delivered to prospective users using a common uniform interface, regardless of the underlying access technologies supporting the communication towards the core network. [0004] A method which supports the delivery of event services is needed to determine when an event is to be triggered based on the prevailing characteristics of the underlying technology. The underlying technology could be supported by the 3GPP specification, 3GPP2 and wireless local area networks (WLANs), (e.g., IEEE 802.11 or IEEE 802.16), and the like. [0005] Currently, there are no procedures or functionality to generate triggers toward upper layers, based on information provided by the 3GPP underlying layers. The IEEE 802.21 specification outlines triggers that should be sent to upper layers. However, the IEEE 802.21 specification does not describe how events are triggered when the underlying physical resources are based on 3GPP technology. Therefore a method capable generating these triggers is required. SUMMARY [0006] The present invention is related to a 3GPP-MIH service access point (SAP) which is configured to provide MIH event services, (e.g., IEEE 802.21 event services), by mapping service primitives to the MIH event services. The service primitives may be 3GPP service primitives which originate from at least one of a radio resources (RR) layer, a logical link control (LLC) layer, a general packet radio service (GPRS) mobility management (GMM) layer, a session management (SM) layer, a non-access stratum (NAS), an access stratum (AS) and an evolved universal terrestrial radio access (E-UTRA)/evolved core network (E-CORE) system. The event services may include a link parameter change event service, a link up event service, a link going down event service, a link down event service, a handover complete event service and a link detected event service. [0007] The present invention uses existing service primitives already defined within 3GPP in order to trigger events that can be used for the determination of handover operations. These service primitives are mapped onto concrete IEEE 802.21 events as defined in IEEE 802.21, as a means to optimize inter-system handover operations. [0008] The present invention provides a method to trigger MIH events, using existing 3GPP radio resource management (RRM), MM and session management (SM) service primitives. The concept of service primitives mapping is extended using mobility management procedures and concepts introduced within both long term evolution (LTE) and system architecture evolution (SAE) within the 3GPP specifications. [0009] The present invention may be applicable to IEEE 802 standards including WLAN baseline air interface standards such as IEEE 802.11 baseline, IEEE 802.11a orthogonal frequency division multiplex (OFDM) 5 GHz WLAN, IEEE 802.11b high rate direct sequence spread spectrum (HR-DSSS) 2.4 GHz WLAN, IEEE 802.11g OFDM 2.4 GHz WLAN, IEEE 802.11j OFDM 10 MHz option WLAN, IEEE 802.11n high-throughput WLAN, and IEEE 802.16 broadband wireless access systems. The WLAN standards supplement to extend operation for particular scenarios such as IEEE 802.21 MIH. [0010] The present invention is also applicable to cellular standards, such as 3GPP or 3GPP2, and other standardized or proprietary wireless technologies similar to IEEE 802 WLANs, examples notably include 802.15 Bluetooth, and HIPERLAN/2. BRIEF DESCRIPTION OF THE DRAWINGS [0011] A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example and to be understood in conjunction with the accompanying drawings wherein: [0012] FIG. 1 shows an 3GPP-MIH SAP which maps 3GPP service primitives, received from various 3GPP entities, to MIH event services in accordance with the present invention; [0013] FIG. 2 is an exemplary block diagram of the MIH-GPP SAP of FIG. 1 ; [0014] FIG. 3 is an example of mapping a 3GPP service primitive to an MIH event service when a page is received by an RR layer; [0015] FIG. 4 is an example of mapping a 3GPP service primitive to an MIH event service when data supporting a specific quality of service (QoS) is received by the RR layer; [0016] FIG. 5 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is established; [0017] FIG. 6 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is released; [0018] FIG. 7 is an example of mapping a 3GPP service primitive to an MIH event service when an LLC layer unrecoverable error occurs; [0019] FIG. 8 is an example of mapping a 3GPP service primitive to an MIH event service when a GMM layer indicates that a station is attached; [0020] FIG. 9 is an example of mapping a 3GPP service primitive to an MIH event service when a GMM layer indicates that a station is detached; [0021] FIG. 10 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is active; [0022] FIG. 11 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is deactivated; [0023] FIG. 12 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is modified; [0024] FIG. 13 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is terminated due to an unrecoverable error; [0025] FIG. 14 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a packet data protocol (PDP) context is active; [0026] FIG. 15 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a PDP context is modified; [0027] FIG. 16 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a PDP context is deactivated; [0028] FIG. 17 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a station is attached; [0029] FIG. 18 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a station is detached; [0030] FIG. 19 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is active; [0031] FIG. 20 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is modified; [0032] FIG. 21 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is deactivated; [0033] FIG. 22 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a radio access bearer (RAB) is activated for data transfer; [0034] FIG. 23 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB is deactivated for data transfer; [0035] FIG. 24 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB is modified for data transfer; [0036] FIG. 25 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB data transfer error has occurred; [0037] FIG. 26 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates that a RAB has been activated; [0038] FIG. 27 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates that a RAB has been released; [0039] FIG. 28 is an example of mapping a 3GPP service primitive to an MIH event service when an AS failure occurs; [0040] FIG. 29 is an example of mapping a 3GPP service primitive to an MIH event service when an AS broadcasts information regarding a geographic area; [0041] FIG. 30 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides notification of paging for a particular user or terminal; [0042] FIG. 31 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides a notification for all users; [0043] FIG. 32 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides notification information for one or more users; [0044] FIG. 33 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a user equipment (UE) initiated connection establishment; [0045] FIG. 34 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated connection release; [0046] FIG. 35 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated RAB establishment; [0047] FIG. 36 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated RAB release; [0048] FIG. 37 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates the potential for an aborted connection unless streamlining is performed; [0049] FIG. 38 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates location information provided by a network for a specific UE; [0050] FIG. 39 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a connection loss; [0051] FIG. 40 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that the location of a UE is now known by a network; [0052] FIG. 41 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that the location of a UE is known to a network but no transport channel is established; and [0053] FIG. 42 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that radio resources have been established and that a UE is able to perform uplink (UL) and downlink (DL) transport of a protocol data unit (PDU). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0054] The present invention is based on the use existing and new, (e.g., LTE and SAE), primitives within 3GPP that can be mapped onto IEEE 802.21 events as defined by the IEEE 802.21 specification. [0055] A primitive is an abstract representation of functions such as an information function, an event or a command. [0056] An MIH event service classifies, filters and reports changes within the link layer characteristics, (i.e., maximum offered throughput, supported bandwidth, or the like), the link status, (i.e., an indicator of whether the link is operational or not), and the link quality, (e.g., low signal strength). Event services may also indicate changes in the state and transmission behavior of the physical, data link and logical link layers. Furthermore, event services are used to indicate an operation state as a result of a management action. [0057] FIG. 1 is a mapping model for 3GPP layer primitives, where a 3GPP-MIH service access point (SAP) 100 maps 3GPP service primitives to MIH event services according to IEEE 802.xx standards. [0058] As shown in FIG. 1 , a radio resources (RR) layer 105 , an LLC layer 110 , a general packet radio service (GPRS) mobility management (GMM) layer 115 , and a session management (SM) layer 120 associated with a global system for mobile communications (GSM)/enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) 125 send 3GPP service primitives 160 to the 3GPP-MIH SAP 100 . Furthermore, the non-access stratum (NAS) 130 and the access stratum (AS) 135 of a universal mobile telecommunications system (UMTS) services 140 send 3GPP service primitives 160 to the SAP 100 . An LTE system 145 sends 3GPP service primitives 160 via an evolved universal terrestrial radio access (E-UTRA) and evolved core network (E-CORE) layers 155 to the SAP 100 . The SAP outputs MIH event services 170 in response to receiving the 3GPP service primitives 160 . [0059] FIG. 2 is an exemplary block diagram of the 3GPP-MIH SAP 100 of FIG. 1 . The 3GPP-MIH SAP 100 includes a processor 205 and a 3GPP to MIH mapping database 210 . When the SAP 100 receives a 3GPP service primitive 160 , the processor 205 in the SAP 100 interprets, (i.e., identifies), the 3GPP service primitive 160 in terms of functional capabilities and potential parameters. The processor 205 then queries the mapping database 210 based on such functional capabilities and parameters to obtain and output the MIH event services 170 . [0060] Table 1 identifies specific 3GPP service primitives for each of the layers of the GERAN 125 shown in FIG. 1 . According to the present invention, the 3GPP service primitives generated by the GERAN 125 via the RR layer 105 , the LLC layer 110 , the GMM layer 115 and the SM layer 120 are mapped to MIH event services, (e.g., IEEE 802.21 events), as shown in Table 1 below. TABLE 1 3GPP 3GPP Service MIH Event Service Layer Primitive Descriptions 3GPP Service Primitive (e.g., IEEE 802.21 Event) RR Page received by RR layer GMRR-PAGE Link Parameter Change Successful reception of data GRR-DATA Link Parameter Change supporting specific QoS LLC Peer LLC layer is LL-ESTABLISH Link Up/Link Parameter established Change Peer LLC layer is released LL-RELEASE Link Going Down/Link Parameter Change LLC Layer unrecoverable LL-STATUS Link Down error GMM Station is attached GMMREG-ATTACH Link Parameter Change Station is detached GMMREG-DETACH Link Parameter Change SM Data session active SMSM-ACTIVE Link Up/Link Parameter Change Data session is deactivated SMSM-DEACTIVATE Link Down/Link Parameter Change Data session modified SMSM-MODIFY Link Parameter Change Data session terminated due SMSM-STATUS Link Down to unrecoverable error PDP Context is active SMREG-PDP-ACTIVATE Link Up/Link Parameter Change/Handover Complete PDP Context is modified SMREG-PDP-MODIFY Link up/Link Parameter Change/Handover Complete PDP Context is deactivated SMREG-PDP-DEACTIVATE Link Going Down/Link Down [0061] FIG. 3 is an example of mapping a 3GPP service primitive to an MIH event service when a page is received by the RR layer 105 . As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the RR layer 105 that indicates that a page was received by the RR layer 105 . This MIH event service may be applicable to any type of standard, such as IEEE 802.21 or the like. [0062] FIG. 4 is an example of mapping a 3GPP service primitive to an MIH event service when data supporting a specific QoS is received by the RR layer 105 . As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the RR layer 105 that indicates that data supporting a specific QoS is received by the RR layer 105 . This MIH event service may be applicable to any type of standard, such as IEEE 802.21 or the like. [0063] FIG. 5 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is established, as indicated by the LLC layer 110 . As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link parameter change event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that a peer LLC layer has been established. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0064] FIG. 6 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer 110 is released, as indicated by the LLC layer 110 . As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that a peer LLC layer has been released. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0065] FIG. 7 is an example of mapping a 3GPP service primitive to an MIH event service when an LLC layer unrecoverable error occurs, as indicated by the LLC layer 110 . As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that an LLC layer unrecoverable error has occurred. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0066] FIG. 8 is an example of mapping a 3GPP service primitive to an MIH event service when the GMM layer 115 indicates that a station is attached. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the GMM layer 115 that indicates that a station is attached. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0067] FIG. 9 is an example of mapping a 3GPP service primitive to an MIH event service when the GMM layer 115 indicates that a station is detached. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the GMM layer 115 that indicates that a station is detached. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0068] FIG. 10 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is active. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session is active. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0069] FIG. 11 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is deactivated. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session is deactivated. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0070] FIG. 12 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is modified. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session has been modified. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0071] FIG. 13 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is terminated due to an unrecoverable error. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session has been terminated due to an unrecoverable error. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0072] FIG. 14 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is active. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context is active. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0073] FIG. 15 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is modified. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context has been modified. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0074] FIG. 16 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is deactivated. As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service or a link down event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context has been deactivated. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0075] Table 2 identifies specific 3GPP service primitives for each of the layers of the UMTS 140 and the LTE system 145 shown in FIG. 1 . According to the present invention, the 3GPP service primitives generated by the UMTS 140 via the NAS 130 and the AS 135 , as well as the 3GPP service primitives generated by the LTE via the E-UTRA/E-CORE system 150 , are mapped to MIH event services, (e.g., IEEE 802.21 events), as shown in Table 2 below. TABLE 2 3GPP Service MIH Event Service 3GPP Primitive 3GPP Service (e.g., IEEE 802.21 Layer Descriptions Primitive Event) NAS Station is attached GMMREG- Link Parameter ATTACH Change Station is detached GMMREG- Link Parameter DETACH Change PDP Context is SMREG-PDP- Link Up/Handover active ACTIVATE Complete/Link Parameter Change PDP Context is SMREG-PDP- Link Parameter modified MODIFY Change/Link Up PDP Context is SMREG-PDP- Link Down/Link deactivated DEACTIVATE Parameter Change Radio Access Bearer RABMSM- Link Up/Link is activated for data ACTIVATE Parameter Change/ transfer Handover Complete Radio Access Bearer RABMSM- Link Down/Link is deactivated for DEACTIVATE Link Parameter data transfer Change Radio Access Bearer RABMSM-MODIFY Link Parameter is modified for data Change/Link Up/ transfer Handover Complete Radio Access Bearer RABMSM-STATUS Link Down data transfer error AS Radio Access Bearer RABMAS-RAB- Link Up/Handover has been activated ESTABLISH Complete Radio Access Bearer RABMAS-RAB- Link Down has been released RELEASE AS failure RABMAS-STATUS Link Down Indication Information Information Link Parameter regarding Broadcast Change geographical area. Notification of Paging Request Link Parameter paging for particular Change user or terminal Notification Notification Link Parameter information for all Broadcast Change users Notification Notification Link Parameter information for a Indication Change specific or for many user UE initiated Connection Link Up connection Establishment establishment Network initiated Infrastructure Side Link Down connection release Initiated Connection Release Network initiated Infrastructure Side Link Up/Link Radio Access Bearer Initiated Radio Detected Establishment Access Bearer Establishment Network initiated Infrastructure Side Link Down Radio Access Bearer Initiated Radio Release Access Bearer Release Indication that the Streamlining Link Going Down connection may be Required Indication aborted unless streamlining is done Location information UE location Link Parameter provided by the information Change network for a specific UE Connection loss Connection loss Link Down indications indication E- The location of the LTE-detached Link Parameter UTRAN/E- UE is now known by Change CORE the network The UE is known to LTE-idle Link Parameter the network but no Change/Link Down transport channel is established Radio resources have LTE-Active Link Up/Link been established and Handover Complete the UE is able to perform UL and DL transport of PDU [0076] FIG. 17 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a station is attached. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a station is attached. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0077] FIG. 18 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a station is detached. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a station is detached. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0078] FIG. 19 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is active. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a handover complete event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is active. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0079] FIG. 20 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is modified. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service or a link up event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is modified. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0080] FIG. 21 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is deactivated. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is deactivated. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0081] FIG. 22 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is activated for data transfer. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is activated for data transfer. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0082] FIG. 23 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is deactivated for data transfer. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is deactivated for data transfer. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0083] FIG. 24 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is modified for data transfer. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service, a link up event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is modified for data transfer. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0084] FIG. 25 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB data transfer error has occurred. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB data transfer error has occurred. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0085] FIG. 26 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates that a RAB has been activated. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB has been activated. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0086] FIG. 27 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates that a RAB has been released. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates that a RAB has been released. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0087] FIG. 28 is an example of mapping a 3GPP service primitive to an MIH event service when a failure of the AS 135 occurs. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates that AS 135 has failed. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0088] FIG. 29 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 broadcasts information regarding a geographic area. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that includes information regarding a geographic area. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0089] FIG. 30 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides notification of paging for a particular user or terminal. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides notification of paging for a particular user or terminal. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0090] FIG. 31 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides a notification for all users. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides notification information for all users. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0091] FIG. 32 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides notification information for one or more users. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides a notification for one or more users. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0092] FIG. 33 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a UE initiated connection establishment. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service in response to receiving a 3GPP service primitive from the AS 135 that indicates a UE initiated connection establishment. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0093] FIG. 34 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated connection release. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated connection release. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0094] FIG. 35 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated RAB establishment. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link detected event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated RAB establishment. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0095] FIG. 36 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated RAB release. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated RAB release. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0096] FIG. 37 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates the potential for an aborted connection unless streamlining is performed. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates the potential for an aborted connection unless streamlining is performed. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0097] FIG. 38 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates location information provided by a network for a specific UE. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that indicates location information provided by a network for a specific UE. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0098] FIG. 39 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a connection loss. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates a connection loss. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0099] FIG. 40 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that the location of a UE is now known by a network. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that the location of a UE is now known by a network. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0100] FIG. 41 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that the location of a UE is known to a network but no transport channel is established. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service or a link down event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that the location of a UE is known to a network but no transport channel is established. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0101] FIG. 42 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that radio resources have been established and that a UE is able to perform UL and DL transport of a PDU. As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link handover complete event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that radio resources have been established and that a UE is able to perform UL and DL transport of a PDU. This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like. [0102] It should be noted that the specific mapping of a 3GPP service primitive to an MIH event service, (e.g., an IEEE 802.21 event), may change. In particular, primitives for SAE and LTE currently remain undefined. However, the present invention demonstrates how mapping service primitives to event services may easily be adapted or used to provide triggers. [0103] Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone (without the other features and elements of the preferred embodiments) or in various combinations with or without other features and elements of the present invention.
A Third Generation Partnership Project (3GPP) media independent handover (MIH) service access point (SAP) is configured to provide MIH event services, (e.g., IEEE 802.21 event services), by mapping service primitives to the MIH event services. The service primitives may be 3GPP service primitives which originate from at least one of a radio resources (RR) layer, a logical link control (LLC) layer, a general packet radio service (GPRS) mobility management (GMM) layer, a session management (SM) layer, a non-access stratum (NAS), an access stratum (AS) and an evolved universal terrestrial radio access (E-UTRA)/evolved core network (E-CORE) system. The event services may include a link parameter change event service, a link up event service, a link going down event service, a link down event service, a handover complete event service and a link detected event service.
Briefly describe the main idea outlined in the provided context.
[ "CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 60/733,703 filed Nov. 4, 2005, which is incorporated by reference as if fully set forth.", "FIELD OF INVENTION [0002] The present invention relates to wireless communication systems.", "More particularly, the present invention relates to mapping of Third Generation Partnership Project (3GPP) service primitives to media independent handover (MIH) event services as defined within the IEEE 802.21 standard.", "BACKGROUND [0003] The IEEE 802.21 standard relates to mechanisms and procedures that aid in the execution and management of inter-system handovers.", "Under the IEEE 802.21 standard, three main services can be accessed by mobility management (MM) applications in order to aid in the management of handover operations and system discovery and system selection.", "These three services include an event service, an information service and a command service, which are delivered to prospective users using a common uniform interface, regardless of the underlying access technologies supporting the communication towards the core network.", "[0004] A method which supports the delivery of event services is needed to determine when an event is to be triggered based on the prevailing characteristics of the underlying technology.", "The underlying technology could be supported by the 3GPP specification, 3GPP2 and wireless local area networks (WLANs), (e.g., IEEE 802.11 or IEEE 802.16), and the like.", "[0005] Currently, there are no procedures or functionality to generate triggers toward upper layers, based on information provided by the 3GPP underlying layers.", "The IEEE 802.21 specification outlines triggers that should be sent to upper layers.", "However, the IEEE 802.21 specification does not describe how events are triggered when the underlying physical resources are based on 3GPP technology.", "Therefore a method capable generating these triggers is required.", "SUMMARY [0006] The present invention is related to a 3GPP-MIH service access point (SAP) which is configured to provide MIH event services, (e.g., IEEE 802.21 event services), by mapping service primitives to the MIH event services.", "The service primitives may be 3GPP service primitives which originate from at least one of a radio resources (RR) layer, a logical link control (LLC) layer, a general packet radio service (GPRS) mobility management (GMM) layer, a session management (SM) layer, a non-access stratum (NAS), an access stratum (AS) and an evolved universal terrestrial radio access (E-UTRA)/evolved core network (E-CORE) system.", "The event services may include a link parameter change event service, a link up event service, a link going down event service, a link down event service, a handover complete event service and a link detected event service.", "[0007] The present invention uses existing service primitives already defined within 3GPP in order to trigger events that can be used for the determination of handover operations.", "These service primitives are mapped onto concrete IEEE 802.21 events as defined in IEEE 802.21, as a means to optimize inter-system handover operations.", "[0008] The present invention provides a method to trigger MIH events, using existing 3GPP radio resource management (RRM), MM and session management (SM) service primitives.", "The concept of service primitives mapping is extended using mobility management procedures and concepts introduced within both long term evolution (LTE) and system architecture evolution (SAE) within the 3GPP specifications.", "[0009] The present invention may be applicable to IEEE 802 standards including WLAN baseline air interface standards such as IEEE 802.11 baseline, IEEE 802.11a orthogonal frequency division multiplex (OFDM) 5 GHz WLAN, IEEE 802.11b high rate direct sequence spread spectrum (HR-DSSS) 2.4 GHz WLAN, IEEE 802.11g OFDM 2.4 GHz WLAN, IEEE 802.11j OFDM 10 MHz option WLAN, IEEE 802.11n high-throughput WLAN, and IEEE 802.16 broadband wireless access systems.", "The WLAN standards supplement to extend operation for particular scenarios such as IEEE 802.21 MIH.", "[0010] The present invention is also applicable to cellular standards, such as 3GPP or 3GPP2, and other standardized or proprietary wireless technologies similar to IEEE 802 WLANs, examples notably include 802.15 Bluetooth, and HIPERLAN/2.", "BRIEF DESCRIPTION OF THE DRAWINGS [0011] A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example and to be understood in conjunction with the accompanying drawings wherein: [0012] FIG. 1 shows an 3GPP-MIH SAP which maps 3GPP service primitives, received from various 3GPP entities, to MIH event services in accordance with the present invention;", "[0013] FIG. 2 is an exemplary block diagram of the MIH-GPP SAP of FIG. 1 ;", "[0014] FIG. 3 is an example of mapping a 3GPP service primitive to an MIH event service when a page is received by an RR layer;", "[0015] FIG. 4 is an example of mapping a 3GPP service primitive to an MIH event service when data supporting a specific quality of service (QoS) is received by the RR layer;", "[0016] FIG. 5 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is established;", "[0017] FIG. 6 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is released;", "[0018] FIG. 7 is an example of mapping a 3GPP service primitive to an MIH event service when an LLC layer unrecoverable error occurs;", "[0019] FIG. 8 is an example of mapping a 3GPP service primitive to an MIH event service when a GMM layer indicates that a station is attached;", "[0020] FIG. 9 is an example of mapping a 3GPP service primitive to an MIH event service when a GMM layer indicates that a station is detached;", "[0021] FIG. 10 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is active;", "[0022] FIG. 11 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is deactivated;", "[0023] FIG. 12 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is modified;", "[0024] FIG. 13 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a data session is terminated due to an unrecoverable error;", "[0025] FIG. 14 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a packet data protocol (PDP) context is active;", "[0026] FIG. 15 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a PDP context is modified;", "[0027] FIG. 16 is an example of mapping a 3GPP service primitive to an MIH event service when an SM layer indicates that a PDP context is deactivated;", "[0028] FIG. 17 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a station is attached;", "[0029] FIG. 18 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a station is detached;", "[0030] FIG. 19 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is active;", "[0031] FIG. 20 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is modified;", "[0032] FIG. 21 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a PDP context is deactivated;", "[0033] FIG. 22 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a radio access bearer (RAB) is activated for data transfer;", "[0034] FIG. 23 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB is deactivated for data transfer;", "[0035] FIG. 24 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB is modified for data transfer;", "[0036] FIG. 25 is an example of mapping a 3GPP service primitive to an MIH event service when an NAS indicates that a RAB data transfer error has occurred;", "[0037] FIG. 26 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates that a RAB has been activated;", "[0038] FIG. 27 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates that a RAB has been released;", "[0039] FIG. 28 is an example of mapping a 3GPP service primitive to an MIH event service when an AS failure occurs;", "[0040] FIG. 29 is an example of mapping a 3GPP service primitive to an MIH event service when an AS broadcasts information regarding a geographic area;", "[0041] FIG. 30 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides notification of paging for a particular user or terminal;", "[0042] FIG. 31 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides a notification for all users;", "[0043] FIG. 32 is an example of mapping a 3GPP service primitive to an MIH event service when an AS provides notification information for one or more users;", "[0044] FIG. 33 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a user equipment (UE) initiated connection establishment;", "[0045] FIG. 34 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated connection release;", "[0046] FIG. 35 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated RAB establishment;", "[0047] FIG. 36 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a network initiated RAB release;", "[0048] FIG. 37 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates the potential for an aborted connection unless streamlining is performed;", "[0049] FIG. 38 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates location information provided by a network for a specific UE;", "[0050] FIG. 39 is an example of mapping a 3GPP service primitive to an MIH event service when an AS indicates a connection loss;", "[0051] FIG. 40 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that the location of a UE is now known by a network;", "[0052] FIG. 41 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that the location of a UE is known to a network but no transport channel is established;", "and [0053] FIG. 42 is an example of mapping a 3GPP service primitive to an MIH event service when an E-UTRA/E-CORE system indicates that radio resources have been established and that a UE is able to perform uplink (UL) and downlink (DL) transport of a protocol data unit (PDU).", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0054] The present invention is based on the use existing and new, (e.g., LTE and SAE), primitives within 3GPP that can be mapped onto IEEE 802.21 events as defined by the IEEE 802.21 specification.", "[0055] A primitive is an abstract representation of functions such as an information function, an event or a command.", "[0056] An MIH event service classifies, filters and reports changes within the link layer characteristics, (i.e., maximum offered throughput, supported bandwidth, or the like), the link status, (i.e., an indicator of whether the link is operational or not), and the link quality, (e.g., low signal strength).", "Event services may also indicate changes in the state and transmission behavior of the physical, data link and logical link layers.", "Furthermore, event services are used to indicate an operation state as a result of a management action.", "[0057] FIG. 1 is a mapping model for 3GPP layer primitives, where a 3GPP-MIH service access point (SAP) 100 maps 3GPP service primitives to MIH event services according to IEEE 802.", "xx standards.", "[0058] As shown in FIG. 1 , a radio resources (RR) layer 105 , an LLC layer 110 , a general packet radio service (GPRS) mobility management (GMM) layer 115 , and a session management (SM) layer 120 associated with a global system for mobile communications (GSM)/enhanced data rates for GSM evolution (EDGE) radio access network (GERAN) 125 send 3GPP service primitives 160 to the 3GPP-MIH SAP 100 .", "Furthermore, the non-access stratum (NAS) 130 and the access stratum (AS) 135 of a universal mobile telecommunications system (UMTS) services 140 send 3GPP service primitives 160 to the SAP 100 .", "An LTE system 145 sends 3GPP service primitives 160 via an evolved universal terrestrial radio access (E-UTRA) and evolved core network (E-CORE) layers 155 to the SAP 100 .", "The SAP outputs MIH event services 170 in response to receiving the 3GPP service primitives 160 .", "[0059] FIG. 2 is an exemplary block diagram of the 3GPP-MIH SAP 100 of FIG. 1 .", "The 3GPP-MIH SAP 100 includes a processor 205 and a 3GPP to MIH mapping database 210 .", "When the SAP 100 receives a 3GPP service primitive 160 , the processor 205 in the SAP 100 interprets, (i.e., identifies), the 3GPP service primitive 160 in terms of functional capabilities and potential parameters.", "The processor 205 then queries the mapping database 210 based on such functional capabilities and parameters to obtain and output the MIH event services 170 .", "[0060] Table 1 identifies specific 3GPP service primitives for each of the layers of the GERAN 125 shown in FIG. 1 .", "According to the present invention, the 3GPP service primitives generated by the GERAN 125 via the RR layer 105 , the LLC layer 110 , the GMM layer 115 and the SM layer 120 are mapped to MIH event services, (e.g., IEEE 802.21 events), as shown in Table 1 below.", "TABLE 1 3GPP 3GPP Service MIH Event Service Layer Primitive Descriptions 3GPP Service Primitive (e.g., IEEE 802.21 Event) RR Page received by RR layer GMRR-PAGE Link Parameter Change Successful reception of data GRR-DATA Link Parameter Change supporting specific QoS LLC Peer LLC layer is LL-ESTABLISH Link Up/Link Parameter established Change Peer LLC layer is released LL-RELEASE Link Going Down/Link Parameter Change LLC Layer unrecoverable LL-STATUS Link Down error GMM Station is attached GMMREG-ATTACH Link Parameter Change Station is detached GMMREG-DETACH Link Parameter Change SM Data session active SMSM-ACTIVE Link Up/Link Parameter Change Data session is deactivated SMSM-DEACTIVATE Link Down/Link Parameter Change Data session modified SMSM-MODIFY Link Parameter Change Data session terminated due SMSM-STATUS Link Down to unrecoverable error PDP Context is active SMREG-PDP-ACTIVATE Link Up/Link Parameter Change/Handover Complete PDP Context is modified SMREG-PDP-MODIFY Link up/Link Parameter Change/Handover Complete PDP Context is deactivated SMREG-PDP-DEACTIVATE Link Going Down/Link Down [0061] FIG. 3 is an example of mapping a 3GPP service primitive to an MIH event service when a page is received by the RR layer 105 .", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the RR layer 105 that indicates that a page was received by the RR layer 105 .", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 or the like.", "[0062] FIG. 4 is an example of mapping a 3GPP service primitive to an MIH event service when data supporting a specific QoS is received by the RR layer 105 .", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the RR layer 105 that indicates that data supporting a specific QoS is received by the RR layer 105 .", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 or the like.", "[0063] FIG. 5 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer is established, as indicated by the LLC layer 110 .", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link parameter change event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that a peer LLC layer has been established.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0064] FIG. 6 is an example of mapping a 3GPP service primitive to an MIH event service when a peer LLC layer 110 is released, as indicated by the LLC layer 110 .", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that a peer LLC layer has been released.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0065] FIG. 7 is an example of mapping a 3GPP service primitive to an MIH event service when an LLC layer unrecoverable error occurs, as indicated by the LLC layer 110 .", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the LLC layer 110 that indicates that an LLC layer unrecoverable error has occurred.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0066] FIG. 8 is an example of mapping a 3GPP service primitive to an MIH event service when the GMM layer 115 indicates that a station is attached.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the GMM layer 115 that indicates that a station is attached.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0067] FIG. 9 is an example of mapping a 3GPP service primitive to an MIH event service when the GMM layer 115 indicates that a station is detached.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the GMM layer 115 that indicates that a station is detached.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0068] FIG. 10 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is active.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session is active.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0069] FIG. 11 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is deactivated.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session is deactivated.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0070] FIG. 12 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is modified.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session has been modified.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0071] FIG. 13 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a data session is terminated due to an unrecoverable error.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a data session has been terminated due to an unrecoverable error.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0072] FIG. 14 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is active.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context is active.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0073] FIG. 15 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is modified.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context has been modified.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0074] FIG. 16 is an example of mapping a 3GPP service primitive to an MIH event service when the SM layer 120 indicates that a PDP context is deactivated.", "As indicated by Table 1 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service or a link down event service in response to receiving a 3GPP service primitive from the SM layer 120 that indicates that a PDP context has been deactivated.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0075] Table 2 identifies specific 3GPP service primitives for each of the layers of the UMTS 140 and the LTE system 145 shown in FIG. 1 .", "According to the present invention, the 3GPP service primitives generated by the UMTS 140 via the NAS 130 and the AS 135 , as well as the 3GPP service primitives generated by the LTE via the E-UTRA/E-CORE system 150 , are mapped to MIH event services, (e.g., IEEE 802.21 events), as shown in Table 2 below.", "TABLE 2 3GPP Service MIH Event Service 3GPP Primitive 3GPP Service (e.g., IEEE 802.21 Layer Descriptions Primitive Event) NAS Station is attached GMMREG- Link Parameter ATTACH Change Station is detached GMMREG- Link Parameter DETACH Change PDP Context is SMREG-PDP- Link Up/Handover active ACTIVATE Complete/Link Parameter Change PDP Context is SMREG-PDP- Link Parameter modified MODIFY Change/Link Up PDP Context is SMREG-PDP- Link Down/Link deactivated DEACTIVATE Parameter Change Radio Access Bearer RABMSM- Link Up/Link is activated for data ACTIVATE Parameter Change/ transfer Handover Complete Radio Access Bearer RABMSM- Link Down/Link is deactivated for DEACTIVATE Link Parameter data transfer Change Radio Access Bearer RABMSM-MODIFY Link Parameter is modified for data Change/Link Up/ transfer Handover Complete Radio Access Bearer RABMSM-STATUS Link Down data transfer error AS Radio Access Bearer RABMAS-RAB- Link Up/Handover has been activated ESTABLISH Complete Radio Access Bearer RABMAS-RAB- Link Down has been released RELEASE AS failure RABMAS-STATUS Link Down Indication Information Information Link Parameter regarding Broadcast Change geographical area.", "Notification of Paging Request Link Parameter paging for particular Change user or terminal Notification Notification Link Parameter information for all Broadcast Change users Notification Notification Link Parameter information for a Indication Change specific or for many user UE initiated Connection Link Up connection Establishment establishment Network initiated Infrastructure Side Link Down connection release Initiated Connection Release Network initiated Infrastructure Side Link Up/Link Radio Access Bearer Initiated Radio Detected Establishment Access Bearer Establishment Network initiated Infrastructure Side Link Down Radio Access Bearer Initiated Radio Release Access Bearer Release Indication that the Streamlining Link Going Down connection may be Required Indication aborted unless streamlining is done Location information UE location Link Parameter provided by the information Change network for a specific UE Connection loss Connection loss Link Down indications indication E- The location of the LTE-detached Link Parameter UTRAN/E- UE is now known by Change CORE the network The UE is known to LTE-idle Link Parameter the network but no Change/Link Down transport channel is established Radio resources have LTE-Active Link Up/Link been established and Handover Complete the UE is able to perform UL and DL transport of PDU [0076] FIG. 17 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a station is attached.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a station is attached.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0077] FIG. 18 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a station is detached.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a station is detached.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0078] FIG. 19 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is active.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a handover complete event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is active.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0079] FIG. 20 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is modified.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service or a link up event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is modified.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0080] FIG. 21 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a PDP context is deactivated.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a PDP context is deactivated.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0081] FIG. 22 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is activated for data transfer.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service, a link parameter change event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is activated for data transfer.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0082] FIG. 23 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is deactivated for data transfer.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service or a link parameter change event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is deactivated for data transfer.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0083] FIG. 24 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB is modified for data transfer.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service, a link up event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB is modified for data transfer.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0084] FIG. 25 is an example of mapping a 3GPP service primitive to an MIH event service when the NAS 130 indicates that a RAB data transfer error has occurred.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB data transfer error has occurred.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0085] FIG. 26 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates that a RAB has been activated.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a handover complete event service in response to receiving a 3GPP service primitive from the NAS 130 that indicates that a RAB has been activated.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0086] FIG. 27 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates that a RAB has been released.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates that a RAB has been released.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0087] FIG. 28 is an example of mapping a 3GPP service primitive to an MIH event service when a failure of the AS 135 occurs.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates that AS 135 has failed.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0088] FIG. 29 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 broadcasts information regarding a geographic area.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that includes information regarding a geographic area.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0089] FIG. 30 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides notification of paging for a particular user or terminal.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides notification of paging for a particular user or terminal.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0090] FIG. 31 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides a notification for all users.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides notification information for all users.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0091] FIG. 32 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 provides notification information for one or more users.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that provides a notification for one or more users.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0092] FIG. 33 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a UE initiated connection establishment.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service in response to receiving a 3GPP service primitive from the AS 135 that indicates a UE initiated connection establishment.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0093] FIG. 34 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated connection release.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated connection release.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0094] FIG. 35 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated RAB establishment.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link detected event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated RAB establishment.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0095] FIG. 36 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a network initiated RAB release.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates an infrastructure side, (i.e., network), initiated RAB release.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0096] FIG. 37 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates the potential for an aborted connection unless streamlining is performed.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link going down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates the potential for an aborted connection unless streamlining is performed.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0097] FIG. 38 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates location information provided by a network for a specific UE.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the AS 135 that indicates location information provided by a network for a specific UE.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0098] FIG. 39 is an example of mapping a 3GPP service primitive to an MIH event service when the AS 135 indicates a connection loss.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link down event service in response to receiving a 3GPP service primitive from the AS 135 that indicates a connection loss.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0099] FIG. 40 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that the location of a UE is now known by a network.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that the location of a UE is now known by a network.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0100] FIG. 41 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that the location of a UE is known to a network but no transport channel is established.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link parameter change event service or a link down event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that the location of a UE is known to a network but no transport channel is established.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0101] FIG. 42 is an example of mapping a 3GPP service primitive to an MIH event service when the E-UTRA/E-CORE system 150 indicates that radio resources have been established and that a UE is able to perform UL and DL transport of a PDU.", "As indicated by Table 2 above, the processor 205 in the SAP 100 illustrated in FIG. 2 outputs a link up event service or a link handover complete event service in response to receiving a 3GPP service primitive from the E-UTRA/E-CORE system 150 that indicates that radio resources have been established and that a UE is able to perform UL and DL transport of a PDU.", "This MIH event service may be applicable to any type of standard, such as IEEE 802.21 and the like.", "[0102] It should be noted that the specific mapping of a 3GPP service primitive to an MIH event service, (e.g., an IEEE 802.21 event), may change.", "In particular, primitives for SAE and LTE currently remain undefined.", "However, the present invention demonstrates how mapping service primitives to event services may easily be adapted or used to provide triggers.", "[0103] Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone (without the other features and elements of the preferred embodiments) or in various combinations with or without other features and elements of the present invention." ]
BACKGROUND OF THE INVENTION When playing a game of golf and in particular when teeing off, a tee, which can also be referred to as a tee peg, is pushed into the ground by means of a pointed tip to support the golf ball at a position above the ground level. When then the ball is struck from its position of being supported on the top of the tee, the tee is often hit out of the ground due to the effect of the striking force applied by the club head, and the tee is frequently also damaged. That means that in many cases tees can only be used for a single stroke and are then left lying around on the golf course, either because they are damaged or because the tee is hit away from its position of being inserted into the ground and can then no longer be found. It will be noted that the tee is inserted into the ground by the player, by manual pressure, which means that to insert the tee the player must stoop over, which may be an uncomfortable position. SUMMARY OF THE INVENTION An object of the present invention is to provide a tee-off arrangement for golf, which can at least substantially reduce the disadvantages outlined above. Another object of the present invention is to provide a tee-off arrangement for golf, which makes the tee considerably easier to handle while further providing that a single tee can also be used for a plurality of teeing-off strokes. Still another object of the present invention is to provide a tee-off arrangement for a game of golf, which makes it easier for a tee to be fitted into the ground to support a ball thereon. In accordance with the principles of the present invention the foregoing and other objects are achieved by a tee-off arrangement for a game of golf, comprising a golf club and a tee which can be inserted into the ground by means of a pointed tip for supporting a golf ball during teeing-off. The golf club is adapted to be releasably connectable to the tee by way of a permanent magnet means. In a preferred feature the golf club has a club shaft and disposed in the upper end region of the club shaft is a first magnet which extends in the longitudinal direction of the club shaft, while the tee, at its side remote from its tip or point, has a second magnet, the pole direction of the magnets being such that a magnetic attraction force is exerted between the free flat side or face of the first magnet of the club and the free end of the second magnet of the tee. Preferably in that arrangement the first magnet of the club is in the form of a bar magnet while the second magnet of the tee is in the form of a flat magnet. Because both components, namely the golf club in its upper end region of its shaft and the tee itself, have permanent magnets, the arrangement according to the invention can provide a sufficiently great magnetic force. Another preferred feature of the invention provides that the upper end region of the shaft of the golf club has a guide and receiving means of sleeve-like or tubular configuration which surrounds a free end portion of the first magnet and the internal profile of which is adapted to receive the external profile of the tee in the region thereof which is disposed around the second magnet. That configuration gives the advantage that, when the upper end of the golf club shaft, which carries the first magnet, is moved towards a tee which for example is lying on the ground, the first and second magnets attract each other in such a way that the free sides or faces of the magnets face towards each other and the region of the tee which is disposed around the second magnet is received by the guide and receiving means provided by the shaft of the golf club. In that situation the insertion point or tip of the tee then faces in the longitudinal direction of the golf club shaft away from the golf club head, so that the player can insert the tee into the ground at the next location at which it is required, without having to bend or stoop over, by pressing the tee into the ground by the use of the club. In that situation the guide and receiving means prevents the tee from veering off laterally while it is being inserted into the ground. The magnetic forces can be so selected that the golf club shaft can be readily removed from the tee after the tee has been inserted into the ground, in opposition to the effect of the magnetic force produced by the permanent magnet means. In accordance with another preferred feature of the invention the first magnet which is fitted in the club is in the form of a bar magnet and is disposed in a sleeve portion which is fitted into the upper end of the tube member extending in the longitudinal direction of and forming part of the club shaft, the guide and receiving means being formed on the sleeve, while the free end of the bar magnet is arranged to project relative to the bottom of the guide and receiving means by the distance by which the free flat side or face of the second flat magnet of the tee is arranged set back therein by virtue of the rounded configuration of the golf ball to be supported thereon. The above-mentioned tube which is usually provided in the interior of the shaft of the golf club comprises either for example metal or plastic material. The end of the tube is usually enclosed by a handle of elastic material. In regard to the manner of mounting the bar magnet as indicated above, the construction in accordance with this preferred feature of the invention affords the advantage that a bar magnet which is for example glued in position in a sleeve as described above can be introduced with the sleeve into the end of the tube of the golf club shaft, a suitable opening first being made in the handle which comprises elastic material. The fact that the free end of the bar magnet projects by the specified distance relative to the bottom of the guide and receiving means provides that the two magnets can bear against each other without an air gap therebetween, thus giving a secure holding effect. A further preferred feature of the invention can provide that the free end of the bar magnet is at least approximately aligned with the end of the shaft of the club, thereby providing that the magnetic force is operative substantially in the region of the free end of the bar magnet and not laterally thereof, thereby preventing the tee, as a result of the effect of the magnetic force, laterally bearing against the shaft of the club, without properly fitting completely into the guide and receiving means. In accordance with another preferred configuration of the invention the region of the tee which has the point or tip thereof can be of a sword-like configuration. In addition, the tee may have blades or vanes constituting laterally projecting portions which are preferably so arranged that they extend transversely to the flat side of the sword-like region. In another preferred feature of the invention the blades or vanes, or laterally projecting portions, have in the region of their junction to the body of the tee a notch or recess such that when the tee is pushed into the ground the blades or vanes exhibit an elastically yielding reaction. The tee is preferably made from plastic material, for example polyamide, more particularly preferably of a fluorescent color so that the tee can be easily found by visual inspection, for example when it has landed on the ground after the ball has been struck from the top of the tee. In regard to the material used the tee can be made so durable that it can be used a plurality of times. Further objects, features and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic view in section of part of a tee-off arrangement according to the invention, showing the upper end of the shaft of a golf club with bar magnet fitted therein, FIG. 2 is a diagrammatic view in section through a tee with a flat magnet fitted therein, FIG. 3 is a diagrammatic view in section taken along line III--III in FIG. 2; and FIG. 4 is a cross-sectional view taken along line IV--IV of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring firstly to FIG. 1, shown therein is the upper end of a shaft 1 of a golf club, forming part of a tee-off arrangement for a game of golf, in accordance with the invention. FIG. 1 does not show the head region of the golf club which comprises a head mounted at the opposite and therefore lower end of the golf club, at an angle to the club shaft 1. The club shaft 1 comprises a tube which is generally identified by reference numeral 2 and which for example comprises metal. In the upper end region the tube 2 is surrounded by a handle portion 3 comprising a suitable elastic material, for example rubber, polyurethane or the like. As indicated, the handle portion embraces the upper end region of the club shaft 1 and normally therefore also the upper end region of the tube 2. As shown in FIG. 1, provided in the upper end region of the handle portion 3 is an opening 4 so that the upper end 5 of the tube 2 is exposed after the opening 4 has been formed. Fitted into the upper end of the tube 2 is a sleeve 6 which in turn receives a magnet in the form of a bar magnet 7 which is secured in the sleeve 6 by suitable means such as glueing. For the purposes of inserting the bar magnet 7 the lower end portion 8 of the sleeve 6 has a vent opening 9 for the release of air from the sleeve 6 as the bar magnet 7 is introduced. Provided on the outside peripheral surface of the sleeve 6 are ribs 10 while provided at the lower end of the sleeve 6 is an annular portion 11. The sleeve 6 is supported with the ribs 10 against the inside surface of the tube 2 and bears with a flange portion 12 disposed at the upper end of the sleeve 6 and extending transversely to the longitudinal direction thereof against the lower end of the opening 4 and thus against the end face 5 of the tube 2. The sleeve 6 is of such a configuration that it enlarges towards its free end, that is to say in its portion which is upward in FIG. 1, and comprises a guide and receiving means 13. The guide and receiving means 13 has an internal profile of round configuration which corresponds to a round external profile as indicated at 14 on a portion of a tee as indicated generally by reference numeral 15 in FIG. 2. Provided on the outside of the guide and receiving means 13 in FIG. 1 is a peripherally extending collar portion 16 which bears against the upper end face of the handle portion 3. Looking now at FIG. 2, the tee or tee peg 15 further comprises a permanent magnet in the form of a flat magnet 17 having a free flat side or face 17a. The flat side or face 17a is arranged to be set back relative to the end 18 of the tee 15, which faces downwardly in FIG. 2, in such a way that the space thus defined by the set-back configuration is suitable for receiving the rounded configuration of the golf ball which is to be struck off the top of the tee 15 when it is inserted into the ground with the golf ball resting thereon. It will be seen therefore that the tee 15 is inserted into the ground by means of a point or tip as indicated at 20, the magnet 17 thus being arranged on the tee 15 at its side which is remote from the point 20. The pole direction of the magnets 7 (FIG. 1) and 17 (FIG. 2) is so selected that a magnetic attraction force is exerted between the face 7a of the magnet 7 of the club and the face 17a of the magnet 17 of the tee 15. Looking again at FIG. 1, the free end of the magnet 7 of the club, as indicated at 7a, is arranged to project beyond the bottom 19 of the guide and receiving means 13 by a distance corresponding to the distance by which the face 17a of the flat magnet 17 is set back in the tee 15, so that, when the tee is received with its region 14 by the space in the guide and receiving means 13, the face 7a of the magnet 7 and the face 17a of the magnet 17 bear against each other without an air gap therebetween. As indicated above, the tee 15 has a point 20 by which the tee can be fitted into the ground to support a golf ball on the tee. The tee further has a body 21, adjoining the point 20, having a flattened elliptical or oval transverse cross-section, as can be seen from FIG. 4. In addition, the tee 15 has blades or vanes 22 forming laterally projecting portions which extend transversely relative to the longitudinal direction of the body 21, at respective sides of the flat side surfaces thereof. In addition, in the region where the blades or vanes 22 are joined to the body of the tee 15, there is a notch or recess as indicated at 23, such that when the tee 15 is pushed into the ground, the blades or vanes 22 exhibit an elastically yielding reaction upon coming into contact with the surface of the ground. It will be seen therefore that, when the tee with the blade-like point portion 20, and body 21 is inserted into the ground in such a way that the flat sides of the body point in the direction in which the ball supported on the tee 15 is to be struck, the body of the tee 15 will cut through the ground like a knife when the tee 15 is hit out of the ground by virtue of the player striking the ball resting on the tee. As a result, the tee presents a lower degree of resistance to its movement through the ground and can thus be more readily disengaged from the ground and flung through the air. That can at least substantially reduce the risk of damage to the tee, which would otherwise be caused by the tee tending to hold fast in the ground even when struck by the club in the course of the player striking the ball. However the blades or vanes 22 serve to increase the wind resistance of the tee so that, when the tee has been hit out of the ground and is flying through the air, the blades or vanes cause the tee to come back to the ground again after a short distance so that the player can pick up the tee again at a relatively small distance from his point of striking the ball, using the shaft of his club. It will be noted however that the blades or vanes 22 also have the effect of causing the tee to assume a stable position when it is pressed into the ground. The notches or recesses 23 which produce the elastically yielding reaction serve to prevent a tee, upon being pressed into the ground, springing back upwardly again as a result of the blades or vanes bearing against the surface of the ground and thus so-to-speak re-extracting the tee upwardly from the ground. It will be seen therefore that the tee-off arrangement according to the invention which provides that the golf club is adapted to be releasably connectable to the tee 15 by way of the permanent magnets 7 and 17 gives the advantage that, after the player has struck the ball from the top of the tee on which the ball was resting and the tee has as a result been flung a distance away from the point of striking, the player can use the handle end of the golf club to pick up the tee again by the co-operation of the respective magnets 7 and 17. It will be appreciated that the above-described arrangement according to the invention ha s been set forth solely by way of example and illustration of the principles of the present invention and that various modifications and alterations may be made therein without thereby departing from the spirit and scope of the invention.
A tee-off arrangement for playing golf includes a golf club and a tee for supporting a golf ball during a teeing-off stroke. The golf club and the tee each have a permanent magnet which cooperate so that the club can be used to pick up the tee from the ground and subsequently inserted in the ground for the next tee shot.
Concisely explain the essential features and purpose of the invention.
[ "BACKGROUND OF THE INVENTION When playing a game of golf and in particular when teeing off, a tee, which can also be referred to as a tee peg, is pushed into the ground by means of a pointed tip to support the golf ball at a position above the ground level.", "When then the ball is struck from its position of being supported on the top of the tee, the tee is often hit out of the ground due to the effect of the striking force applied by the club head, and the tee is frequently also damaged.", "That means that in many cases tees can only be used for a single stroke and are then left lying around on the golf course, either because they are damaged or because the tee is hit away from its position of being inserted into the ground and can then no longer be found.", "It will be noted that the tee is inserted into the ground by the player, by manual pressure, which means that to insert the tee the player must stoop over, which may be an uncomfortable position.", "SUMMARY OF THE INVENTION An object of the present invention is to provide a tee-off arrangement for golf, which can at least substantially reduce the disadvantages outlined above.", "Another object of the present invention is to provide a tee-off arrangement for golf, which makes the tee considerably easier to handle while further providing that a single tee can also be used for a plurality of teeing-off strokes.", "Still another object of the present invention is to provide a tee-off arrangement for a game of golf, which makes it easier for a tee to be fitted into the ground to support a ball thereon.", "In accordance with the principles of the present invention the foregoing and other objects are achieved by a tee-off arrangement for a game of golf, comprising a golf club and a tee which can be inserted into the ground by means of a pointed tip for supporting a golf ball during teeing-off.", "The golf club is adapted to be releasably connectable to the tee by way of a permanent magnet means.", "In a preferred feature the golf club has a club shaft and disposed in the upper end region of the club shaft is a first magnet which extends in the longitudinal direction of the club shaft, while the tee, at its side remote from its tip or point, has a second magnet, the pole direction of the magnets being such that a magnetic attraction force is exerted between the free flat side or face of the first magnet of the club and the free end of the second magnet of the tee.", "Preferably in that arrangement the first magnet of the club is in the form of a bar magnet while the second magnet of the tee is in the form of a flat magnet.", "Because both components, namely the golf club in its upper end region of its shaft and the tee itself, have permanent magnets, the arrangement according to the invention can provide a sufficiently great magnetic force.", "Another preferred feature of the invention provides that the upper end region of the shaft of the golf club has a guide and receiving means of sleeve-like or tubular configuration which surrounds a free end portion of the first magnet and the internal profile of which is adapted to receive the external profile of the tee in the region thereof which is disposed around the second magnet.", "That configuration gives the advantage that, when the upper end of the golf club shaft, which carries the first magnet, is moved towards a tee which for example is lying on the ground, the first and second magnets attract each other in such a way that the free sides or faces of the magnets face towards each other and the region of the tee which is disposed around the second magnet is received by the guide and receiving means provided by the shaft of the golf club.", "In that situation the insertion point or tip of the tee then faces in the longitudinal direction of the golf club shaft away from the golf club head, so that the player can insert the tee into the ground at the next location at which it is required, without having to bend or stoop over, by pressing the tee into the ground by the use of the club.", "In that situation the guide and receiving means prevents the tee from veering off laterally while it is being inserted into the ground.", "The magnetic forces can be so selected that the golf club shaft can be readily removed from the tee after the tee has been inserted into the ground, in opposition to the effect of the magnetic force produced by the permanent magnet means.", "In accordance with another preferred feature of the invention the first magnet which is fitted in the club is in the form of a bar magnet and is disposed in a sleeve portion which is fitted into the upper end of the tube member extending in the longitudinal direction of and forming part of the club shaft, the guide and receiving means being formed on the sleeve, while the free end of the bar magnet is arranged to project relative to the bottom of the guide and receiving means by the distance by which the free flat side or face of the second flat magnet of the tee is arranged set back therein by virtue of the rounded configuration of the golf ball to be supported thereon.", "The above-mentioned tube which is usually provided in the interior of the shaft of the golf club comprises either for example metal or plastic material.", "The end of the tube is usually enclosed by a handle of elastic material.", "In regard to the manner of mounting the bar magnet as indicated above, the construction in accordance with this preferred feature of the invention affords the advantage that a bar magnet which is for example glued in position in a sleeve as described above can be introduced with the sleeve into the end of the tube of the golf club shaft, a suitable opening first being made in the handle which comprises elastic material.", "The fact that the free end of the bar magnet projects by the specified distance relative to the bottom of the guide and receiving means provides that the two magnets can bear against each other without an air gap therebetween, thus giving a secure holding effect.", "A further preferred feature of the invention can provide that the free end of the bar magnet is at least approximately aligned with the end of the shaft of the club, thereby providing that the magnetic force is operative substantially in the region of the free end of the bar magnet and not laterally thereof, thereby preventing the tee, as a result of the effect of the magnetic force, laterally bearing against the shaft of the club, without properly fitting completely into the guide and receiving means.", "In accordance with another preferred configuration of the invention the region of the tee which has the point or tip thereof can be of a sword-like configuration.", "In addition, the tee may have blades or vanes constituting laterally projecting portions which are preferably so arranged that they extend transversely to the flat side of the sword-like region.", "In another preferred feature of the invention the blades or vanes, or laterally projecting portions, have in the region of their junction to the body of the tee a notch or recess such that when the tee is pushed into the ground the blades or vanes exhibit an elastically yielding reaction.", "The tee is preferably made from plastic material, for example polyamide, more particularly preferably of a fluorescent color so that the tee can be easily found by visual inspection, for example when it has landed on the ground after the ball has been struck from the top of the tee.", "In regard to the material used the tee can be made so durable that it can be used a plurality of times.", "Further objects, features and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof.", "BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic view in section of part of a tee-off arrangement according to the invention, showing the upper end of the shaft of a golf club with bar magnet fitted therein, FIG. 2 is a diagrammatic view in section through a tee with a flat magnet fitted therein, FIG. 3 is a diagrammatic view in section taken along line III--III in FIG. 2;", "and FIG. 4 is a cross-sectional view taken along line IV--IV of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring firstly to FIG. 1, shown therein is the upper end of a shaft 1 of a golf club, forming part of a tee-off arrangement for a game of golf, in accordance with the invention.", "FIG. 1 does not show the head region of the golf club which comprises a head mounted at the opposite and therefore lower end of the golf club, at an angle to the club shaft 1.", "The club shaft 1 comprises a tube which is generally identified by reference numeral 2 and which for example comprises metal.", "In the upper end region the tube 2 is surrounded by a handle portion 3 comprising a suitable elastic material, for example rubber, polyurethane or the like.", "As indicated, the handle portion embraces the upper end region of the club shaft 1 and normally therefore also the upper end region of the tube 2.", "As shown in FIG. 1, provided in the upper end region of the handle portion 3 is an opening 4 so that the upper end 5 of the tube 2 is exposed after the opening 4 has been formed.", "Fitted into the upper end of the tube 2 is a sleeve 6 which in turn receives a magnet in the form of a bar magnet 7 which is secured in the sleeve 6 by suitable means such as glueing.", "For the purposes of inserting the bar magnet 7 the lower end portion 8 of the sleeve 6 has a vent opening 9 for the release of air from the sleeve 6 as the bar magnet 7 is introduced.", "Provided on the outside peripheral surface of the sleeve 6 are ribs 10 while provided at the lower end of the sleeve 6 is an annular portion 11.", "The sleeve 6 is supported with the ribs 10 against the inside surface of the tube 2 and bears with a flange portion 12 disposed at the upper end of the sleeve 6 and extending transversely to the longitudinal direction thereof against the lower end of the opening 4 and thus against the end face 5 of the tube 2.", "The sleeve 6 is of such a configuration that it enlarges towards its free end, that is to say in its portion which is upward in FIG. 1, and comprises a guide and receiving means 13.", "The guide and receiving means 13 has an internal profile of round configuration which corresponds to a round external profile as indicated at 14 on a portion of a tee as indicated generally by reference numeral 15 in FIG. 2. Provided on the outside of the guide and receiving means 13 in FIG. 1 is a peripherally extending collar portion 16 which bears against the upper end face of the handle portion 3.", "Looking now at FIG. 2, the tee or tee peg 15 further comprises a permanent magnet in the form of a flat magnet 17 having a free flat side or face 17a.", "The flat side or face 17a is arranged to be set back relative to the end 18 of the tee 15, which faces downwardly in FIG. 2, in such a way that the space thus defined by the set-back configuration is suitable for receiving the rounded configuration of the golf ball which is to be struck off the top of the tee 15 when it is inserted into the ground with the golf ball resting thereon.", "It will be seen therefore that the tee 15 is inserted into the ground by means of a point or tip as indicated at 20, the magnet 17 thus being arranged on the tee 15 at its side which is remote from the point 20.", "The pole direction of the magnets 7 (FIG.", "1) and 17 (FIG.", "2) is so selected that a magnetic attraction force is exerted between the face 7a of the magnet 7 of the club and the face 17a of the magnet 17 of the tee 15.", "Looking again at FIG. 1, the free end of the magnet 7 of the club, as indicated at 7a, is arranged to project beyond the bottom 19 of the guide and receiving means 13 by a distance corresponding to the distance by which the face 17a of the flat magnet 17 is set back in the tee 15, so that, when the tee is received with its region 14 by the space in the guide and receiving means 13, the face 7a of the magnet 7 and the face 17a of the magnet 17 bear against each other without an air gap therebetween.", "As indicated above, the tee 15 has a point 20 by which the tee can be fitted into the ground to support a golf ball on the tee.", "The tee further has a body 21, adjoining the point 20, having a flattened elliptical or oval transverse cross-section, as can be seen from FIG. 4. In addition, the tee 15 has blades or vanes 22 forming laterally projecting portions which extend transversely relative to the longitudinal direction of the body 21, at respective sides of the flat side surfaces thereof.", "In addition, in the region where the blades or vanes 22 are joined to the body of the tee 15, there is a notch or recess as indicated at 23, such that when the tee 15 is pushed into the ground, the blades or vanes 22 exhibit an elastically yielding reaction upon coming into contact with the surface of the ground.", "It will be seen therefore that, when the tee with the blade-like point portion 20, and body 21 is inserted into the ground in such a way that the flat sides of the body point in the direction in which the ball supported on the tee 15 is to be struck, the body of the tee 15 will cut through the ground like a knife when the tee 15 is hit out of the ground by virtue of the player striking the ball resting on the tee.", "As a result, the tee presents a lower degree of resistance to its movement through the ground and can thus be more readily disengaged from the ground and flung through the air.", "That can at least substantially reduce the risk of damage to the tee, which would otherwise be caused by the tee tending to hold fast in the ground even when struck by the club in the course of the player striking the ball.", "However the blades or vanes 22 serve to increase the wind resistance of the tee so that, when the tee has been hit out of the ground and is flying through the air, the blades or vanes cause the tee to come back to the ground again after a short distance so that the player can pick up the tee again at a relatively small distance from his point of striking the ball, using the shaft of his club.", "It will be noted however that the blades or vanes 22 also have the effect of causing the tee to assume a stable position when it is pressed into the ground.", "The notches or recesses 23 which produce the elastically yielding reaction serve to prevent a tee, upon being pressed into the ground, springing back upwardly again as a result of the blades or vanes bearing against the surface of the ground and thus so-to-speak re-extracting the tee upwardly from the ground.", "It will be seen therefore that the tee-off arrangement according to the invention which provides that the golf club is adapted to be releasably connectable to the tee 15 by way of the permanent magnets 7 and 17 gives the advantage that, after the player has struck the ball from the top of the tee on which the ball was resting and the tee has as a result been flung a distance away from the point of striking, the player can use the handle end of the golf club to pick up the tee again by the co-operation of the respective magnets 7 and 17.", "It will be appreciated that the above-described arrangement according to the invention ha s been set forth solely by way of example and illustration of the principles of the present invention and that various modifications and alterations may be made therein without thereby departing from the spirit and scope of the invention." ]
BACKGROUND This application is a continuation of application Ser. No. 08/841,440, filed Apr. 22, 1997 entitled Making Enhanced Data Cable with Cross-Twist Cabled Core Profile (as amended) now U.S. Pat. No. 6,074,503. FIELD OF THE INVENTION The present invention relates to high-speed data communications cables using at least two twisted pairs of wires. More particularly, it relates to cables having a central core defining plural individual pair channels. RELATED ART High-speed data communications media in current usage include pairs of wire twisted together to form a balanced transmission line. Such pairs of wire are referred to as twisted pairs. One common type of conventional cable for high-speed data communications includes multiple twisted pairs. When twisted pairs are closely placed, such as in a cable, electrical energy may be transferred from one pair of a cable to another. Such energy transferred between pairs is undesirable and referred to as crosstalk. The Telecommunications Industry Association and Electronics Industry Association have defined standards for crosstalk, including TIA/EIA-568A. The International Electrotechnical Commission has also defined standards for data communication cable crosstalk, including ISO/IEC 11801. One high-performance standard for 100Ω cable is ISO/IEC 11801, Category 5. In conventional cable, each twisted pair of a cable has a specified distance between twists along the longitudinal direction, that distance being referred to as the pair lay. When adjacent twisted pairs have the same pair lay and/or twist direction, they tend to lie within a cable more closely spaced than when they have different pair lays and/or twist direction. Such close spacing increases the amount of undesirable crosstalk which occurs. Therefore, in some conventional cables, each twisted pair within the cable has a unique pair lay in order to increase the spacing between pairs and thereby to reduce the crosstalk between twisted pairs of a cable. Twist direction may also be varied. Along with varying pair lays and twist directions, individual solid metal or woven metal pair shields are sometimes used to electromagnetically isolate pairs. Shielded cable, although exhibiting better crosstalk isolation, is more difficult and time consuming to install and terminate. Shield conductors are generally terminated using special tools, devices and techniques adapted for the job. One popular cable type meeting the above specifications is Unshielded Twisted Pair (UTP) cable. Because it does not include shield conductors, UTP is preferred by installers and plant managers, as it is easily installed and terminated. However, UTP fails to achieve superior crosstalk isolation, as required by state of the art transmission systems, even when varying pair lays are used. Another solution to the problem of twisted pairs lying too closely together within a cable is embodied in a cable manufactured by Belden Wire & Cable Company as product number 1711A. This cable includes four twisted pair media radially disposed about a “+”-shaped core. Each twisted pair nests between two fins of the “+”-shaped core, being separated from adjacent twisted pairs by the core. This helps reduce and stabilize crosstalk between the twisted pair media. However, the core adds substantial cost to the cable, as well as material which forms a potential fire hazard, as explained below, while achieving a crosstalk reduction of only about 5 dB. In building design, many precautions are taken to resist the spread of flame and the generation of and spread of smoke throughout a building in case of an outbreak of fire. Clearly, it is desired to protect against loss of life and also to minimize the costs of a fire due to the destruction of electrical and other equipment. Therefore, wires and cables for in building installations are required to comply with the various flammability requirements of the National Electrical Code (NEC) and/or the Canadian Electrical Code (CEC). Cables intended for installation in the air handling spaces (ie. plenums, ducts, etc.) of buildings are specifically required by NEC or CEC to pass the flame test specified by Underwriters Laboratories Inc. (UL), UL-910, or it's Canadian Standards Association (CSA) equivalent, the FT6. The UL-910 and the FT6 represent the top of the fire rating hierarchy established by the NEC and CEC respectively. Cables possessing this rating, generically known as “plenum” or “plenum rated”, may be substituted for cables having a lower rating (ie. CMR, CM, CMX, FT4, FT1 or their equivalents), while lower rated cables may not be used where plenum rated cable is required. Cables conforming to NEC or CEC requirements are characterized as possessing superior resistance to ignitability, greater resistant to contribute to flame spread and generate lower levels of smoke during fires than cables having a lower fire rating. Conventional designs of data grade telecommunications cables for installation in plenum chambers have a low smoke generating jacket material, e.g. of a PVC formulation or a fluoropolymer material, surrounding a core of twisted conductor pairs, each conductor individually insulated with a fluorinated ethylene propylene (FEP) insulation layer. Cable produced as described above satisfies recognized plenum test requirements such as the “peak smoke” and “average smoke” requirements of the Underwriters Laboratories, Inc., UL910 Steiner test and/or Canadian Standards Association CSA-FT6 (Plenum Flame Test) while also achieving desired electrical performance in accordance with EIA/TIA-568A for high frequency signal transmission. While the above-described conventional cable including the Belden 1711A cable due in part to their use of FEP meets all of the above design criteria, the use of fluorinated ethylene propylene is extremely expensive and may account for up to 60% of the cost of a cable designed for plenum usage. The solid core of the Belden 1711A cable contributes a large volume of fuel to a cable fire. Forming the core of a fire resistant material, such as FEP, is very costly due to the volume of material used in the core. Solid flame retardant/smoke suppressed polyolefin may also be used in connection with FEP. Solid flame retardant/smoke suppressed polyolefin compounds commercially available all possess dielectric properties inferior to that of FEP. In addition, they also exhibit inferior resistance to burning and generally produce more smoke than FEP under burning conditions than FEP. SUMMARY OF THE INVENTION This invention provides an improved data cable. According to one embodiment, the cable includes a plurality of transmission media; a core having a surface defining recesses within which each of the plurality of transmission media are individually disposed; and an outer jacket maintaining the plurality of data transmission media in position with respect to the core. According to another embodiment of the invention, a cable includes a plurality of transmission media radially disposed about a core having a surface with features which maintain a separation between each of the plurality of transmission media. Finally, according to yet another embodiment of the invention, there is a method of producing a cable. The method first passes a plurality of transmission media and a core through a first die which aligns the plurality of transmission media with surface features of the core and prevents twisting motion of the core. Next, the method bunches the aligned plurality of transmission media and core using a second die which forces each of the plurality of transmission media into contact with the surface features of the core which maintain a spatial relationship between each of the plurality of transmission media. Finally, the bunched plurality of transmission media and core are twisted to close the cable, and the closed cable is jacketed. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, in which like reference numerals designate like elements: FIG. 1 is a cross-sectional view of a cable core used in embodiments of the invention; FIG. 2 is a cross-sectional view of one embodiment of a cable including the core of FIG. 1; FIG. 3 is a cross-sectional view of another embodiment of a cable including the core of FIG. 1; FIG. 4 is a perspective view of a die system for practicing a method of making a cable in accordance with another embodiment of the invention; FIG. 5 is a cross-sectional view of another embodiment of a cable core used in some embodiments of the cable of the invention; and FIG. 6 is a cross-sectional view of another embodiment of a cable core used in some embodiments of the cable of the invention. DETAILED DESCRIPTION An embodiment of the invention is now described in which a cable is constructed to include four twisted pairs of wire and a core having a unique profile. However, the invention is not limited to the number of pairs or the profile used in this embodiment. The inventive principles can be applied to cables including greater or fewer numbers of twisted pairs and different core profiles. Also, although this embodiment of the invention is described and illustrated in connection with twisted pair data communication media, other high-speed data communication media can be used in constructions of cable according to the invention. This illustrative embodiment of the invention, as shown in FIG. 1, includes an extruded core 101 having a profile described below cabled into the cable with four twisted pairs 103 . The extruded core profile has an initial shape of a “+”, providing four spaces or channels 105 between each pair of fins of the core. Each channel 105 carries one twisted pair 103 placed within the channel 105 during the cabling operation. The illustrated core 101 and profile should not be considered limiting. The core 101 may be made by some other process than extrusion and may have a different initial shape or number of channels 105 . For example, as illustrated in FIG. 5, there may be an optional central channel 107 provided to carry a fiber optic element 501 . The above-described embodiment can be constructed using a number of different materials. While the invention is not limited to the materials now given, the invention is advantageously practiced using these materials. The core material should be a conductive material or one containing a powdered ferrite, the core material being generally compatible with use in data communications cable applications, including any applicable fire safety standards. In non-plenum applications, the core can be formed of solid or foamed flame retardant polyolefin or similar materials. In plenum applications, the core can be any one or more of the following compounds: a solid low dielectric constant fluoropolymer, e.g., ethylene chlortrifluoroethylene (E-CTFE) or fluorinated ethylene propylene (FEP), a foamed fluoropolymer, e.g., foamed FEP, and polyvinyl chloride (PVC) in either solid, low dielectric constant form or foamed. A filler is added to the compound to render the extruded product conductive. Suitable fillers are those compatible with the compound into which they are mixed, including but not limited to powdered ferrite, semiconductive thermoplastic elastomers and carbon black. Conductivity of the core helps to further isolate the twisted pairs from each other. A conventional four-pair cable including a non-conductive core, such as the Belden 1711A cable, reduces nominal crosstalk by up to 5 dB over similar, four-pair cable without the core. By making the core conductive, crosstalk is reduced a further 5 dB. Since both loading and jacket construction can affect crosstalk, these figures compare cables with similar loading and jacket construction. The cable may be finished in any one of several conventional ways, as shown in FIG. 2 . The combined core 101 and twisted pairs 103 may be optionally wrapped with a dielectric tape 201 , then jacketed 203 to form cable 200 . An overall conductive shield 205 can optionally be applied over the cable before jacketing to prevent the cable from causing or receiving electromagnetic interference. The jacket 203 may be PVC or another material as discussed above in relation to the core 101 . The dielectric tape 201 may be polyester, or another compound generally compatible with data communications cable applications, including any applicable fire safety standards. Greater cross-talk isolation is achieved in the construction of FIG. 3, by using a conductive shield 301 , for example a metal braid, a solid metal foil shield or a conductive plastic layer in contact with the ends of the fins 303 of the core 101 . Such a construction rivals individual shielding of twisted pairs for cross-talk isolation. This construction optionally can advantageously include a drain wire 601 in a central channel 107 , as illustrated in FIG. 6 . In the constructions of both FIGS. 2 and 3 it is advantageous to have the fins 303 of the core 101 extend somewhat beyond a boundary defined by the outer dimension of the twisted pairs 103 . In the construction of FIG. 2 this ensures that he twisted pairs 103 do not escape their respective channels 105 prior to the cable being jacketed, while in that of FIG. 3 and good contact between the fins 303 and the shield 301 is ensured. In both constructions, closing and jacketing the cable may bend the tips of the fins 303 over slightly, as shown in the core material is relatively soft, such as PVC. A method of making cable in accordance with the above-described embodiments is now described. As is known in this art, when plural elements are cabled together, an overall twist is imparted to the assembly to improve geometric stability and help prevent separation. In embodiments of the present invention, twisting of the profile of the core along with the individual twisted pairs is controlled. The process allows the extruded core to maintain a physical spacing between the twisted pairs and maintains geometrical stability within the cable. Thus, the process assists in the achievement of and maintenance of high crosstalk isolation by placing a conductive core in the cable to maintain pair spacing. Cables of the previously described embodiments, can be made by a three-part die system. However, methods of making such cables are not limited to a three-part die system, as more or fewer die elements can be constructed to incorporate the features of the invention. The extruded core is drawn from a payoff reel (not shown) through the central opening 401 in die 403 . Four twisted pairs are initially aligned with the core by passing through openings 405 in die 403 . The core is next brought through opening 407 and brought together with the four twisted pairs which are passed through openings 409 in a second die 411 , then cabled with the twisted pairs which are pushed into the channels of the core by a third die 413 , in an operation called bunching. The second die 411 eliminates back twist, which is inherent in bunching operations, thus allowing the third die 413 to place the pairs in the channels prior to the twisting. The cable twist is imparted to the cable assembly after the second die 411 , which locates the twisted pairs relative to the extruded core profile. Although the method of making cable has been described in connection with an extruded core delivered into the process from a payoff reel, the invention is not so limited. For example, the core could be extruded immediately prior to use and transferred directly from the extruder to the central opening 401 of the first die 403 . In another variation, the core could be extruded directly through a properly shaped central opening of either the first die 403 or the second die 411 . The present invention has now been described in connection with a number of specific embodiments thereof. However, numerous modifications which are contemplated as falling within the scope of the present invention should now be apparent to those skilled in the art. Therefore, it is intended that the scope of the present invention be limited only by the scope of the claims appended hereto.
A cable exhibiting reduced crosstalk between transmission media includes a core having a profile with a shape which defines spaces or channels to maintain a spacing between transmission media in a finished cable. The core is formed of a conductive material to further reduce crosstalk. A method of producing a cable introduces a core as described above into the cable assembly and imparts a cable closing twist to the assembly.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "BACKGROUND This application is a continuation of application Ser.", "No. 08/841,440, filed Apr. 22, 1997 entitled Making Enhanced Data Cable with Cross-Twist Cabled Core Profile (as amended) now U.S. Pat. No. 6,074,503.", "FIELD OF THE INVENTION The present invention relates to high-speed data communications cables using at least two twisted pairs of wires.", "More particularly, it relates to cables having a central core defining plural individual pair channels.", "RELATED ART High-speed data communications media in current usage include pairs of wire twisted together to form a balanced transmission line.", "Such pairs of wire are referred to as twisted pairs.", "One common type of conventional cable for high-speed data communications includes multiple twisted pairs.", "When twisted pairs are closely placed, such as in a cable, electrical energy may be transferred from one pair of a cable to another.", "Such energy transferred between pairs is undesirable and referred to as crosstalk.", "The Telecommunications Industry Association and Electronics Industry Association have defined standards for crosstalk, including TIA/EIA-568A.", "The International Electrotechnical Commission has also defined standards for data communication cable crosstalk, including ISO/IEC 11801.", "One high-performance standard for 100Ω cable is ISO/IEC 11801, Category 5.", "In conventional cable, each twisted pair of a cable has a specified distance between twists along the longitudinal direction, that distance being referred to as the pair lay.", "When adjacent twisted pairs have the same pair lay and/or twist direction, they tend to lie within a cable more closely spaced than when they have different pair lays and/or twist direction.", "Such close spacing increases the amount of undesirable crosstalk which occurs.", "Therefore, in some conventional cables, each twisted pair within the cable has a unique pair lay in order to increase the spacing between pairs and thereby to reduce the crosstalk between twisted pairs of a cable.", "Twist direction may also be varied.", "Along with varying pair lays and twist directions, individual solid metal or woven metal pair shields are sometimes used to electromagnetically isolate pairs.", "Shielded cable, although exhibiting better crosstalk isolation, is more difficult and time consuming to install and terminate.", "Shield conductors are generally terminated using special tools, devices and techniques adapted for the job.", "One popular cable type meeting the above specifications is Unshielded Twisted Pair (UTP) cable.", "Because it does not include shield conductors, UTP is preferred by installers and plant managers, as it is easily installed and terminated.", "However, UTP fails to achieve superior crosstalk isolation, as required by state of the art transmission systems, even when varying pair lays are used.", "Another solution to the problem of twisted pairs lying too closely together within a cable is embodied in a cable manufactured by Belden Wire &", "Cable Company as product number 1711A.", "This cable includes four twisted pair media radially disposed about a “+”-shaped core.", "Each twisted pair nests between two fins of the “+”-shaped core, being separated from adjacent twisted pairs by the core.", "This helps reduce and stabilize crosstalk between the twisted pair media.", "However, the core adds substantial cost to the cable, as well as material which forms a potential fire hazard, as explained below, while achieving a crosstalk reduction of only about 5 dB.", "In building design, many precautions are taken to resist the spread of flame and the generation of and spread of smoke throughout a building in case of an outbreak of fire.", "Clearly, it is desired to protect against loss of life and also to minimize the costs of a fire due to the destruction of electrical and other equipment.", "Therefore, wires and cables for in building installations are required to comply with the various flammability requirements of the National Electrical Code (NEC) and/or the Canadian Electrical Code (CEC).", "Cables intended for installation in the air handling spaces (ie.", "plenums, ducts, etc.) of buildings are specifically required by NEC or CEC to pass the flame test specified by Underwriters Laboratories Inc. (UL), UL-910, or it's Canadian Standards Association (CSA) equivalent, the FT6.", "The UL-910 and the FT6 represent the top of the fire rating hierarchy established by the NEC and CEC respectively.", "Cables possessing this rating, generically known as “plenum”", "or “plenum rated”, may be substituted for cables having a lower rating (ie.", "CMR, CM, CMX, FT4, FT1 or their equivalents), while lower rated cables may not be used where plenum rated cable is required.", "Cables conforming to NEC or CEC requirements are characterized as possessing superior resistance to ignitability, greater resistant to contribute to flame spread and generate lower levels of smoke during fires than cables having a lower fire rating.", "Conventional designs of data grade telecommunications cables for installation in plenum chambers have a low smoke generating jacket material, e.g. of a PVC formulation or a fluoropolymer material, surrounding a core of twisted conductor pairs, each conductor individually insulated with a fluorinated ethylene propylene (FEP) insulation layer.", "Cable produced as described above satisfies recognized plenum test requirements such as the “peak smoke”", "and “average smoke”", "requirements of the Underwriters Laboratories, Inc., UL910 Steiner test and/or Canadian Standards Association CSA-FT6 (Plenum Flame Test) while also achieving desired electrical performance in accordance with EIA/TIA-568A for high frequency signal transmission.", "While the above-described conventional cable including the Belden 1711A cable due in part to their use of FEP meets all of the above design criteria, the use of fluorinated ethylene propylene is extremely expensive and may account for up to 60% of the cost of a cable designed for plenum usage.", "The solid core of the Belden 1711A cable contributes a large volume of fuel to a cable fire.", "Forming the core of a fire resistant material, such as FEP, is very costly due to the volume of material used in the core.", "Solid flame retardant/smoke suppressed polyolefin may also be used in connection with FEP.", "Solid flame retardant/smoke suppressed polyolefin compounds commercially available all possess dielectric properties inferior to that of FEP.", "In addition, they also exhibit inferior resistance to burning and generally produce more smoke than FEP under burning conditions than FEP.", "SUMMARY OF THE INVENTION This invention provides an improved data cable.", "According to one embodiment, the cable includes a plurality of transmission media;", "a core having a surface defining recesses within which each of the plurality of transmission media are individually disposed;", "and an outer jacket maintaining the plurality of data transmission media in position with respect to the core.", "According to another embodiment of the invention, a cable includes a plurality of transmission media radially disposed about a core having a surface with features which maintain a separation between each of the plurality of transmission media.", "Finally, according to yet another embodiment of the invention, there is a method of producing a cable.", "The method first passes a plurality of transmission media and a core through a first die which aligns the plurality of transmission media with surface features of the core and prevents twisting motion of the core.", "Next, the method bunches the aligned plurality of transmission media and core using a second die which forces each of the plurality of transmission media into contact with the surface features of the core which maintain a spatial relationship between each of the plurality of transmission media.", "Finally, the bunched plurality of transmission media and core are twisted to close the cable, and the closed cable is jacketed.", "BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, in which like reference numerals designate like elements: FIG. 1 is a cross-sectional view of a cable core used in embodiments of the invention;", "FIG. 2 is a cross-sectional view of one embodiment of a cable including the core of FIG. 1;", "FIG. 3 is a cross-sectional view of another embodiment of a cable including the core of FIG. 1;", "FIG. 4 is a perspective view of a die system for practicing a method of making a cable in accordance with another embodiment of the invention;", "FIG. 5 is a cross-sectional view of another embodiment of a cable core used in some embodiments of the cable of the invention;", "and FIG. 6 is a cross-sectional view of another embodiment of a cable core used in some embodiments of the cable of the invention.", "DETAILED DESCRIPTION An embodiment of the invention is now described in which a cable is constructed to include four twisted pairs of wire and a core having a unique profile.", "However, the invention is not limited to the number of pairs or the profile used in this embodiment.", "The inventive principles can be applied to cables including greater or fewer numbers of twisted pairs and different core profiles.", "Also, although this embodiment of the invention is described and illustrated in connection with twisted pair data communication media, other high-speed data communication media can be used in constructions of cable according to the invention.", "This illustrative embodiment of the invention, as shown in FIG. 1, includes an extruded core 101 having a profile described below cabled into the cable with four twisted pairs 103 .", "The extruded core profile has an initial shape of a “+”, providing four spaces or channels 105 between each pair of fins of the core.", "Each channel 105 carries one twisted pair 103 placed within the channel 105 during the cabling operation.", "The illustrated core 101 and profile should not be considered limiting.", "The core 101 may be made by some other process than extrusion and may have a different initial shape or number of channels 105 .", "For example, as illustrated in FIG. 5, there may be an optional central channel 107 provided to carry a fiber optic element 501 .", "The above-described embodiment can be constructed using a number of different materials.", "While the invention is not limited to the materials now given, the invention is advantageously practiced using these materials.", "The core material should be a conductive material or one containing a powdered ferrite, the core material being generally compatible with use in data communications cable applications, including any applicable fire safety standards.", "In non-plenum applications, the core can be formed of solid or foamed flame retardant polyolefin or similar materials.", "In plenum applications, the core can be any one or more of the following compounds: a solid low dielectric constant fluoropolymer, e.g., ethylene chlortrifluoroethylene (E-CTFE) or fluorinated ethylene propylene (FEP), a foamed fluoropolymer, e.g., foamed FEP, and polyvinyl chloride (PVC) in either solid, low dielectric constant form or foamed.", "A filler is added to the compound to render the extruded product conductive.", "Suitable fillers are those compatible with the compound into which they are mixed, including but not limited to powdered ferrite, semiconductive thermoplastic elastomers and carbon black.", "Conductivity of the core helps to further isolate the twisted pairs from each other.", "A conventional four-pair cable including a non-conductive core, such as the Belden 1711A cable, reduces nominal crosstalk by up to 5 dB over similar, four-pair cable without the core.", "By making the core conductive, crosstalk is reduced a further 5 dB.", "Since both loading and jacket construction can affect crosstalk, these figures compare cables with similar loading and jacket construction.", "The cable may be finished in any one of several conventional ways, as shown in FIG. 2 .", "The combined core 101 and twisted pairs 103 may be optionally wrapped with a dielectric tape 201 , then jacketed 203 to form cable 200 .", "An overall conductive shield 205 can optionally be applied over the cable before jacketing to prevent the cable from causing or receiving electromagnetic interference.", "The jacket 203 may be PVC or another material as discussed above in relation to the core 101 .", "The dielectric tape 201 may be polyester, or another compound generally compatible with data communications cable applications, including any applicable fire safety standards.", "Greater cross-talk isolation is achieved in the construction of FIG. 3, by using a conductive shield 301 , for example a metal braid, a solid metal foil shield or a conductive plastic layer in contact with the ends of the fins 303 of the core 101 .", "Such a construction rivals individual shielding of twisted pairs for cross-talk isolation.", "This construction optionally can advantageously include a drain wire 601 in a central channel 107 , as illustrated in FIG. 6 .", "In the constructions of both FIGS. 2 and 3 it is advantageous to have the fins 303 of the core 101 extend somewhat beyond a boundary defined by the outer dimension of the twisted pairs 103 .", "In the construction of FIG. 2 this ensures that he twisted pairs 103 do not escape their respective channels 105 prior to the cable being jacketed, while in that of FIG. 3 and good contact between the fins 303 and the shield 301 is ensured.", "In both constructions, closing and jacketing the cable may bend the tips of the fins 303 over slightly, as shown in the core material is relatively soft, such as PVC.", "A method of making cable in accordance with the above-described embodiments is now described.", "As is known in this art, when plural elements are cabled together, an overall twist is imparted to the assembly to improve geometric stability and help prevent separation.", "In embodiments of the present invention, twisting of the profile of the core along with the individual twisted pairs is controlled.", "The process allows the extruded core to maintain a physical spacing between the twisted pairs and maintains geometrical stability within the cable.", "Thus, the process assists in the achievement of and maintenance of high crosstalk isolation by placing a conductive core in the cable to maintain pair spacing.", "Cables of the previously described embodiments, can be made by a three-part die system.", "However, methods of making such cables are not limited to a three-part die system, as more or fewer die elements can be constructed to incorporate the features of the invention.", "The extruded core is drawn from a payoff reel (not shown) through the central opening 401 in die 403 .", "Four twisted pairs are initially aligned with the core by passing through openings 405 in die 403 .", "The core is next brought through opening 407 and brought together with the four twisted pairs which are passed through openings 409 in a second die 411 , then cabled with the twisted pairs which are pushed into the channels of the core by a third die 413 , in an operation called bunching.", "The second die 411 eliminates back twist, which is inherent in bunching operations, thus allowing the third die 413 to place the pairs in the channels prior to the twisting.", "The cable twist is imparted to the cable assembly after the second die 411 , which locates the twisted pairs relative to the extruded core profile.", "Although the method of making cable has been described in connection with an extruded core delivered into the process from a payoff reel, the invention is not so limited.", "For example, the core could be extruded immediately prior to use and transferred directly from the extruder to the central opening 401 of the first die 403 .", "In another variation, the core could be extruded directly through a properly shaped central opening of either the first die 403 or the second die 411 .", "The present invention has now been described in connection with a number of specific embodiments thereof.", "However, numerous modifications which are contemplated as falling within the scope of the present invention should now be apparent to those skilled in the art.", "Therefore, it is intended that the scope of the present invention be limited only by the scope of the claims appended hereto." ]
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to European Patent Application 97203986.1 dated Dec. 18, 1987 via corresponding International Application Number PTC/U98/26423 filed Dec. 11, 1998 and published as WO 99/31177 on Jun. 24, 1999. BACKGROUND OF THE INVENTION This invention relates to thermoplastic polymer compositions which are thermoformable, and to thermoformed articles made from such compositions. The compositions of the present invention, which are halogen-free, are useful for making laminates, sheets and films, and for replacing polyvinyl chloride (PVC) resins in many of their traditional uses. In particular, compositions of the present invention, and thermoformed articles made therefrom, are suitable as PVC replacements in the automotive field. They may be used in the fabrication of interior sheathing of automobiles, for example, in the instrument panel skins, door panels, roof liners and seat covers. Automotive applications require certain properties in the resins, including good flexibility, low temperature properties, capability of providing a soft surface texture and grain retention; as well as good high temperature properties and low emissions associated with it in view of the extreme temperatures the interior of automobiles can reach on hot, sunny days. PVC-free compositions comprising a blend of polypropylene, ethylene copolymer ionomer resin, ethylene/glycidyl acrylate or methacrylate copolymer, and uncrosslinked ethylene propylene rubber are described in U.S. Pat. No. 5,206,294. Such a blend has been proven suitable for most applications and it is characterized by good thermoformability and grain retention. This blend has some drawbacks, however, in applications where thin gauges are required. At gauges around 1 mm and thinner, the low embossing depth may lead to insufficient grain retention; moreover, this blend may be too costly for certain applications. DE 196 10 415, assigned to Schulman GMBH. discloses compounds for injection molding application. The compositions include a polyolefin, a noncrosslinked cthylone propylene copolymer, an ionomeric copolymer, a carboxylic acid compound and an epoxide compound. The epoxide compound must be of the following formula: wherein n=0-10, R 1 =hydrogen, an alkyl, aralkyl or aryl group, and R 2 is an alkyl, aralkyl, alkylalkoxy, cycloalkyl, or cycloalkenyl group, and R 3 is if n is not equal to 0, and R 3 =hydrogen if n=0. The epoxide compound may be n-butylglyidyl ether, 2-ethylhexylglycidyl ether, glycidyl ethers of long-chain aliphatic alcohols, among others. EP 0 452 010 A2 discloses thermoplastic resin compositions, having good toughness and resistance to heat deformation, comprising crystalline propylene polymer, random stytenic copolymer, clastomeric olefin polymer selected from ethylene-propyleno-copolymer, ethylene-propylene-diene terpolymers, etc., and an epoxy group-containing olefinic copolymer. SUMMARY OF THE INVENTION The present invention provides a composition suitable for thermoforming which demonstrates good grain retention at thin gauges, low gloss and whose cost is competitive for many applications. This composition contains (a) 10-35 wt. % of polypropylene or an ethylene/propylene copolymer, (b) 0-30 wt. % uncrosslinked ethylene propyleie copolymer rubber having an ethylene content of 60-80 wt. %, (c) 10-25 wt. % of an ionomeric copolymer of ethylene and an α,β-unsaturated C 3 -C 8 carboxylic acid, (d) 2-6 wt. % of a copolymer of ethylene and glycidyl acrylate or glycidyl methacrylate, (e) 5-20 wt. % polyethylene, and (f) 0-25 wt. % of an ethylene alpha-olefin copolymer elastoiner. As such the present invention also provides a thermoforned article made from the above composition and in particular a thermoformed instrument panel skih); including such articles that are laminated to foam prior to thermoforming. DETAILED DESCRIPTION OF THE INVENTION Component (a) of the composition may be a polypropylene or an ethylene/propylene copolymer, or a mixture thereof. Where component (a) contains a polypropylene, the polypropylene component consists of crystalline polypropylene and is intended to include in addition to the homopolymer those polymers that also contain minor amounts, usually not greater than 15 wt %, of higher or lower α-olefins, e.g. those containing 3-8 carbon atoms, such as ethylene, butene, octene, etc. The polypropylene polymers useful in this invention have melt indices in the range of from about 0.07-30 g/10 min at 230° C./2.16 kg. Where component (a) contains an ethylene/propylene copolymer, the copolymer will contain usually more than 15 wt % ethylene. Such polymers are well known to those skilled in the art and are commercially available. Component (a) is present in the composition of the present invention in amounts of 10-35 wt. %, preferably 20-30 wt. %. The uncrosslinked ethylene/propylene copolymer rubber (component (b)) may be an ethylene/propylene/nonconjugated diene copolymer (EPDM) or an ethylene/propylene copolymer (EPM). EPDMs are preferred as component (b). The uncrosslinked ethylene/propylene copolymer rubber contains about 60-80 wt. %, usually about 65-75 wt % ethylene. The nonconjugated dienes can contain from 6-22 carbon atoms having at least one readily polymerizable double bond. The amount of nonconjugated diene is generally from about 1-7 wt. %, usually 2-5 wt. %. EPDM copolymers that are especially preferred are ethylene/propylene/1,4-hexadiene, ethylene/propylene/dicyclopentadiene, ethylene/propylene/norbornene, ethylene/propylene/methylene-2-norbornene and ethylene/propylene/1,4-hexadiene/norbornadiene. It is preferred that the ethylene/propylene copolymer rubber are non-crosslinked. The ethylene/propylene copolymer rubber present as component (a)(ii) in the blend is present in amounts of 15-50 wt. %, preferably 15-40 wt. %. Component (b) is present in the composition of the present invention in amounts of 0-30 wt. %, preferably 10-30 wt. %. The ionic copolymer of ethylene and an α,β-unsaturated C 3 -C 8 carboxylic acid (component (c)) optionally contains at least one softening comonomer that is copolymerizable with ethylene. Acrylic and methacrylic acids are preferred acid comonomers. The softening comonomer can be an alkyl acrylate selected from the group consisting of n-propyl-, n-butyl, n-octyl, 2-ethylhexyl-, and 2-methoxethyl-acrylates. The preferred alkyl acrylates are n-butyl-, 2-ethylhexyl-, and 2-methoxyethyl-acrylates. The softening comonomer can also be an alkyl vinyl ether selected from the group consisting of n-butyl, n-hexyl, 2-ethylhexyl-, and 2-methoxyethyl-vinyl ether. The preferred alkyl vinyl ethers are n-butyl vinyl ether and n-hexyl vinyl ether. The coplymer is about 10 to 70% neutralized with metal ions selected from groups Ia, Ib, Ia, IIIa, IVa, VIb, and VIII of the Periodic Table of Elements such as sodium, potassium zinc, calcium, magnesium, lithium, aluminum, nickel, and chrominum. Preferably the copolymer has from about 35 to about 70% of the carboxylic acid groups ionized by neutralization with metal ions selected from the group consisting of sodium, potassium, zinc, calcium, and magnesium. Component (c) is present in the composition of the present invention in amounts of 10-25 wt. %, preferably 15-20 wt. %. The copolymer of ethylene and glycidyl acrylate or ethylene and glycidyl methacrylate (component (d)) preferably contains copolymerized units of an alkyl acrylate or an alkyl methacrylate having 1-6 carbon atoms. The ethylene/glycidyl acrylate or ethylenel-glycidyl methacrylate copolymer contains 60-88 weight percent ethylene and 1-12 weight percent glycidyl acrylate or glycidyl methacrylate. Representative alkyl acrylates and alkyl methacrylates that are used in the copolymer include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and hexyl methacrylate. Ethyl acrylate is preferred and n-butyl acrylate is especially preferred. The ethylene/glycidyl (meth)acrylate copolymer can be prepared by direct polymerization, for example, copolymerizing ethylene, an alkyl acrylate, and glycidyl methacrylate or glycidyl acrylate in the presence of a free-radical polymerization initiator at elevated temperatures, generally 100°-230° C., and at elevated pressures, i.e. 140-350 MPa. The most preferred ethylene/glycidyl (methacrylate copolymers that are used in this invention are copolymers of ethylene, ethyl acrylate, glycidyl methacrylate, and, especially, ethylene, n-butyl acrylate, and glycidyl methacrylate. Component (d) is present in the composition of the present invention in amounts of 2-6 wt %, preferably 4-6 wt %. The polyethylene component (component (e)) is preferably a linear low density polyethylene (LLDPE). LLDPE is a class of low density polyethylene characterized by little, if any, long chain branching, in contrast to conventional LDPE. The processes for producing LLDPE are well known in the art and commercial grades of this polyolefin are available. The term LLDPE means copolymers of ethylene and other alpha-olefins such as 1-butene, 1-hexene, and 1-octene. LLDPEs suitable for the present invention preferably have a melt flow index at 190° C./2.16 kg of less than 1, more preferably less than 0.5. Component (e) is present in the composition of the present invention in amounts of 5-30 wt. %, preferably 10-20 wt %. The ethylene alpha-olefin copolymer elastomer (component (f)) is a copolymer of ethylene with alpha-olefins having 3-20 carbon atoms, preferably 4-8 carbon atoms (cf. U.S. Pat. Nos. 5,272,236, 5,278,272; PCT WO 94/06817). Alpha-olefins are 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecene, preferably 1-butene, 1-hexen and 1-octene. Component (f) is present in the composition of the present invention in amounts of 0-25 wt %, preferably 15-25 wt %. The thermoplastic polymer compositions of the present invention are generally prepared by melt blending the polymeric components under high shear conditions, for example in an extruder. The various ingredients may first be combined with one another e.g., in a pellet blend, or they may be combined with one another via simultaneous or separate metering of the various components. They may also be divided and blended in on or more passes into separate sections of the mixing equipment. The resultant compositions may be thermoformed into a variety of articles, including sheets, or they may be molded into any desired shape. In particular, they may be thermoformed at high deep-draw ratios for use as instrument panel skins for automobiles. In addition, articles may be laminated to a foam prior to thermoforming. These laminates are particularly useful in automotive applications. Excellent low temperature flexibility and high temperature resistance enables compositions according to the present invention to be useful in applications wherein a wide range of temperature and abrasive conditions are encountered. In addition, as these compositions resist sticking to metal at elevated temperatures, e.g. 150-200° C., they can be used in processes in which hot polymer comes into pressure contact with hot metal rolls. The invention can be further understood by the following examples in which parts and percentages are by weight unless otherwise indicated. EXAMPLES The compositions are compounded in a 25 mm PRISM twin screw extruder. All ingredients were prepared as a salt and pepper blend and granulated after exiting the extruder. The granulate obtained this way is melted in another extruder where 1 mm thick sheets are extruded and are embossed subsequently on an embossing roll. The sheets are then thermoformed over a commercial dashboard form. Grain definition and gloss are compared subjectively. Components used in the examples are: 1 MOPLEN® 30CS polypropylene homopolymer—melt flow index 8 g/10 min at 230° C. ASTM D-1238, Condition L, made by Montell 2 HIFAX® CA12A polypropylene/ethylene copolymer made by Montell 3 NORDEL® 3681 ethylene/propylene/1,4-hexadiene made by DuPont-Dow Elastomers 4 SURLYN® 9520 zinc ionomer made by DuPont 5 ELVALOY® AS etl>ylene/n-butyl acrylate/glycidyl methacrylate made by DuPont 6 STAMILAN® 2200TC00 polyethylene—MFI=0.3; DSM 1808 polyethylene—MFI=8 made by DSM ENGAGE® 8150 ethylene-octene copolymer elastomer made by DuPont-Dow Elastomers Elvaloy AS and Surlyn are trade names of E.I. du Pont de Nemours for their polymer modifiers and ionomer resins, respectively Stamilin is a tradename of DSM for their polyethylene resins Engage and Nordel are tradenames of DuPont-Dow Elastomers for their ethylene octene copolymers and their EPDM elastomer resins respectively. Hifax is a tradename of Montell for their polypropylene reactor copolymers Moplen is a tradename of Montell for their polypropylene resins Amounts are given in weight % Control 1 2 3 4 5 MOPLEN 30CS 20 20 HIFAX CA12A 30 30 30 30 10 NORDEL 3681 44 20 ENGAGE 8150 18 28 28 25 25 ELVALOY AS 2 2 2 2 6 6 SURLYN 9520 34 20 20 20 20 20 DSM 1808 10 20 STAMILAN 20 19 19 2200TC00 Results MFI 0.03 0.06 0.3 0.2 N/A 0.04 Embossing poor good good good good good Grain retention v good best best Thermoformability good poor poor fair fair fair Gloss low high high low lowest lowest The test results indicate that replacing NORDEL rubber in whole or in part with polyethylene improves embossing performance (increases embossing depth) but also increases MFI, which in turn increases undesired gloss. In these cases it is desirable to use a low MFI polyethylene and a high level of crosslinking agent ELVALOY AS in order to obtain a sheet with low gloss, good embossing and low MFI. Thermoforming, however, suffers slightly due to the presence of two different polyolefins (polyethylene and polypropylene) with different melting temperatures.
A composition suitable for thermoforming which demonstrates good grain retention at thin gauges, low gloss and whose cost is competitive for many applications, particularly in the automotive industry, is described. This composition contains (a) 10-35 wt. % of polypropylene or an ethylene/propylene copolymer, (b) 0-30 wt. % uncrosslinked ethylene propylene copolymer rubber having an ethylene content 60-80 wt. %, (c) 10-25 wt. % of an ionomeric copolymer of ethylene and an α, β-unsaturated C 3 -C 8 carboxylic acid, (d) 2-6 wt. % of a copolymer of ethylene and glycidyl acrylate or glycidyl methacrylate, (e) 5-20 wt. % polyethylene, and (f) 0-25 wt. % of an ethylene alpha-olefin copolymer elastomer.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to European Patent Application 97203986.1 dated Dec. 18, 1987 via corresponding International Application Number PTC/U98/26423 filed Dec. 11, 1998 and published as WO 99/31177 on Jun. 24, 1999.", "BACKGROUND OF THE INVENTION This invention relates to thermoplastic polymer compositions which are thermoformable, and to thermoformed articles made from such compositions.", "The compositions of the present invention, which are halogen-free, are useful for making laminates, sheets and films, and for replacing polyvinyl chloride (PVC) resins in many of their traditional uses.", "In particular, compositions of the present invention, and thermoformed articles made therefrom, are suitable as PVC replacements in the automotive field.", "They may be used in the fabrication of interior sheathing of automobiles, for example, in the instrument panel skins, door panels, roof liners and seat covers.", "Automotive applications require certain properties in the resins, including good flexibility, low temperature properties, capability of providing a soft surface texture and grain retention;", "as well as good high temperature properties and low emissions associated with it in view of the extreme temperatures the interior of automobiles can reach on hot, sunny days.", "PVC-free compositions comprising a blend of polypropylene, ethylene copolymer ionomer resin, ethylene/glycidyl acrylate or methacrylate copolymer, and uncrosslinked ethylene propylene rubber are described in U.S. Pat. No. 5,206,294.", "Such a blend has been proven suitable for most applications and it is characterized by good thermoformability and grain retention.", "This blend has some drawbacks, however, in applications where thin gauges are required.", "At gauges around 1 mm and thinner, the low embossing depth may lead to insufficient grain retention;", "moreover, this blend may be too costly for certain applications.", "DE 196 10 415, assigned to Schulman GMBH.", "discloses compounds for injection molding application.", "The compositions include a polyolefin, a noncrosslinked cthylone propylene copolymer, an ionomeric copolymer, a carboxylic acid compound and an epoxide compound.", "The epoxide compound must be of the following formula: wherein n=0-10, R 1 =hydrogen, an alkyl, aralkyl or aryl group, and R 2 is an alkyl, aralkyl, alkylalkoxy, cycloalkyl, or cycloalkenyl group, and R 3 is if n is not equal to 0, and R 3 =hydrogen if n=0.", "The epoxide compound may be n-butylglyidyl ether, 2-ethylhexylglycidyl ether, glycidyl ethers of long-chain aliphatic alcohols, among others.", "EP 0 452 010 A2 discloses thermoplastic resin compositions, having good toughness and resistance to heat deformation, comprising crystalline propylene polymer, random stytenic copolymer, clastomeric olefin polymer selected from ethylene-propyleno-copolymer, ethylene-propylene-diene terpolymers, etc.", ", and an epoxy group-containing olefinic copolymer.", "SUMMARY OF THE INVENTION The present invention provides a composition suitable for thermoforming which demonstrates good grain retention at thin gauges, low gloss and whose cost is competitive for many applications.", "This composition contains (a) 10-35 wt.", "% of polypropylene or an ethylene/propylene copolymer, (b) 0-30 wt.", "% uncrosslinked ethylene propyleie copolymer rubber having an ethylene content of 60-80 wt.", "%, (c) 10-25 wt.", "% of an ionomeric copolymer of ethylene and an α,β-unsaturated C 3 -C 8 carboxylic acid, (d) 2-6 wt.", "% of a copolymer of ethylene and glycidyl acrylate or glycidyl methacrylate, (e) 5-20 wt.", "% polyethylene, and (f) 0-25 wt.", "% of an ethylene alpha-olefin copolymer elastoiner.", "As such the present invention also provides a thermoforned article made from the above composition and in particular a thermoformed instrument panel skih);", "including such articles that are laminated to foam prior to thermoforming.", "DETAILED DESCRIPTION OF THE INVENTION Component (a) of the composition may be a polypropylene or an ethylene/propylene copolymer, or a mixture thereof.", "Where component (a) contains a polypropylene, the polypropylene component consists of crystalline polypropylene and is intended to include in addition to the homopolymer those polymers that also contain minor amounts, usually not greater than 15 wt %, of higher or lower α-olefins, e.g. those containing 3-8 carbon atoms, such as ethylene, butene, octene, etc.", "The polypropylene polymers useful in this invention have melt indices in the range of from about 0.07-30 g/10 min at 230° C./2.16 kg.", "Where component (a) contains an ethylene/propylene copolymer, the copolymer will contain usually more than 15 wt % ethylene.", "Such polymers are well known to those skilled in the art and are commercially available.", "Component (a) is present in the composition of the present invention in amounts of 10-35 wt.", "%, preferably 20-30 wt.", "The uncrosslinked ethylene/propylene copolymer rubber (component (b)) may be an ethylene/propylene/nonconjugated diene copolymer (EPDM) or an ethylene/propylene copolymer (EPM).", "EPDMs are preferred as component (b).", "The uncrosslinked ethylene/propylene copolymer rubber contains about 60-80 wt.", "%, usually about 65-75 wt % ethylene.", "The nonconjugated dienes can contain from 6-22 carbon atoms having at least one readily polymerizable double bond.", "The amount of nonconjugated diene is generally from about 1-7 wt.", "%, usually 2-5 wt.", "EPDM copolymers that are especially preferred are ethylene/propylene/1,4-hexadiene, ethylene/propylene/dicyclopentadiene, ethylene/propylene/norbornene, ethylene/propylene/methylene-2-norbornene and ethylene/propylene/1,4-hexadiene/norbornadiene.", "It is preferred that the ethylene/propylene copolymer rubber are non-crosslinked.", "The ethylene/propylene copolymer rubber present as component (a)(ii) in the blend is present in amounts of 15-50 wt.", "%, preferably 15-40 wt.", "Component (b) is present in the composition of the present invention in amounts of 0-30 wt.", "%, preferably 10-30 wt.", "The ionic copolymer of ethylene and an α,β-unsaturated C 3 -C 8 carboxylic acid (component (c)) optionally contains at least one softening comonomer that is copolymerizable with ethylene.", "Acrylic and methacrylic acids are preferred acid comonomers.", "The softening comonomer can be an alkyl acrylate selected from the group consisting of n-propyl-, n-butyl, n-octyl, 2-ethylhexyl-, and 2-methoxethyl-acrylates.", "The preferred alkyl acrylates are n-butyl-, 2-ethylhexyl-, and 2-methoxyethyl-acrylates.", "The softening comonomer can also be an alkyl vinyl ether selected from the group consisting of n-butyl, n-hexyl, 2-ethylhexyl-, and 2-methoxyethyl-vinyl ether.", "The preferred alkyl vinyl ethers are n-butyl vinyl ether and n-hexyl vinyl ether.", "The coplymer is about 10 to 70% neutralized with metal ions selected from groups Ia, Ib, Ia, IIIa, IVa, VIb, and VIII of the Periodic Table of Elements such as sodium, potassium zinc, calcium, magnesium, lithium, aluminum, nickel, and chrominum.", "Preferably the copolymer has from about 35 to about 70% of the carboxylic acid groups ionized by neutralization with metal ions selected from the group consisting of sodium, potassium, zinc, calcium, and magnesium.", "Component (c) is present in the composition of the present invention in amounts of 10-25 wt.", "%, preferably 15-20 wt.", "The copolymer of ethylene and glycidyl acrylate or ethylene and glycidyl methacrylate (component (d)) preferably contains copolymerized units of an alkyl acrylate or an alkyl methacrylate having 1-6 carbon atoms.", "The ethylene/glycidyl acrylate or ethylenel-glycidyl methacrylate copolymer contains 60-88 weight percent ethylene and 1-12 weight percent glycidyl acrylate or glycidyl methacrylate.", "Representative alkyl acrylates and alkyl methacrylates that are used in the copolymer include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and hexyl methacrylate.", "Ethyl acrylate is preferred and n-butyl acrylate is especially preferred.", "The ethylene/glycidyl (meth)acrylate copolymer can be prepared by direct polymerization, for example, copolymerizing ethylene, an alkyl acrylate, and glycidyl methacrylate or glycidyl acrylate in the presence of a free-radical polymerization initiator at elevated temperatures, generally 100°-230° C., and at elevated pressures, i.e. 140-350 MPa.", "The most preferred ethylene/glycidyl (methacrylate copolymers that are used in this invention are copolymers of ethylene, ethyl acrylate, glycidyl methacrylate, and, especially, ethylene, n-butyl acrylate, and glycidyl methacrylate.", "Component (d) is present in the composition of the present invention in amounts of 2-6 wt %, preferably 4-6 wt %.", "The polyethylene component (component (e)) is preferably a linear low density polyethylene (LLDPE).", "LLDPE is a class of low density polyethylene characterized by little, if any, long chain branching, in contrast to conventional LDPE.", "The processes for producing LLDPE are well known in the art and commercial grades of this polyolefin are available.", "The term LLDPE means copolymers of ethylene and other alpha-olefins such as 1-butene, 1-hexene, and 1-octene.", "LLDPEs suitable for the present invention preferably have a melt flow index at 190° C./2.16 kg of less than 1, more preferably less than 0.5.", "Component (e) is present in the composition of the present invention in amounts of 5-30 wt.", "%, preferably 10-20 wt %.", "The ethylene alpha-olefin copolymer elastomer (component (f)) is a copolymer of ethylene with alpha-olefins having 3-20 carbon atoms, preferably 4-8 carbon atoms (cf.", "U.S. Pat. Nos. 5,272,236, 5,278,272;", "PCT WO 94/06817).", "Alpha-olefins are 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecene, preferably 1-butene, 1-hexen and 1-octene.", "Component (f) is present in the composition of the present invention in amounts of 0-25 wt %, preferably 15-25 wt %.", "The thermoplastic polymer compositions of the present invention are generally prepared by melt blending the polymeric components under high shear conditions, for example in an extruder.", "The various ingredients may first be combined with one another e.g., in a pellet blend, or they may be combined with one another via simultaneous or separate metering of the various components.", "They may also be divided and blended in on or more passes into separate sections of the mixing equipment.", "The resultant compositions may be thermoformed into a variety of articles, including sheets, or they may be molded into any desired shape.", "In particular, they may be thermoformed at high deep-draw ratios for use as instrument panel skins for automobiles.", "In addition, articles may be laminated to a foam prior to thermoforming.", "These laminates are particularly useful in automotive applications.", "Excellent low temperature flexibility and high temperature resistance enables compositions according to the present invention to be useful in applications wherein a wide range of temperature and abrasive conditions are encountered.", "In addition, as these compositions resist sticking to metal at elevated temperatures, e.g. 150-200° C., they can be used in processes in which hot polymer comes into pressure contact with hot metal rolls.", "The invention can be further understood by the following examples in which parts and percentages are by weight unless otherwise indicated.", "EXAMPLES The compositions are compounded in a 25 mm PRISM twin screw extruder.", "All ingredients were prepared as a salt and pepper blend and granulated after exiting the extruder.", "The granulate obtained this way is melted in another extruder where 1 mm thick sheets are extruded and are embossed subsequently on an embossing roll.", "The sheets are then thermoformed over a commercial dashboard form.", "Grain definition and gloss are compared subjectively.", "Components used in the examples are: 1 MOPLEN® 30CS polypropylene homopolymer—melt flow index 8 g/10 min at 230° C. ASTM D-1238, Condition L, made by Montell 2 HIFAX® CA12A polypropylene/ethylene copolymer made by Montell 3 NORDEL® 3681 ethylene/propylene/1,4-hexadiene made by DuPont-Dow Elastomers 4 SURLYN® 9520 zinc ionomer made by DuPont 5 ELVALOY® AS etl>ylene/n-butyl acrylate/glycidyl methacrylate made by DuPont 6 STAMILAN® 2200TC00 polyethylene—MFI=0.3;", "DSM 1808 polyethylene—MFI=8 made by DSM ENGAGE® 8150 ethylene-octene copolymer elastomer made by DuPont-Dow Elastomers Elvaloy AS and Surlyn are trade names of E.I. du Pont de Nemours for their polymer modifiers and ionomer resins, respectively Stamilin is a tradename of DSM for their polyethylene resins Engage and Nordel are tradenames of DuPont-Dow Elastomers for their ethylene octene copolymers and their EPDM elastomer resins respectively.", "Hifax is a tradename of Montell for their polypropylene reactor copolymers Moplen is a tradename of Montell for their polypropylene resins Amounts are given in weight % Control 1 2 3 4 5 MOPLEN 30CS 20 20 HIFAX CA12A 30 30 30 30 10 NORDEL 3681 44 20 ENGAGE 8150 18 28 28 25 25 ELVALOY AS 2 2 2 2 6 6 SURLYN 9520 34 20 20 20 20 20 DSM 1808 10 20 STAMILAN 20 19 19 2200TC00 Results MFI 0.03 0.06 0.3 0.2 N/A 0.04 Embossing poor good good good good good Grain retention v good best best Thermoformability good poor poor fair fair fair Gloss low high high low lowest lowest The test results indicate that replacing NORDEL rubber in whole or in part with polyethylene improves embossing performance (increases embossing depth) but also increases MFI, which in turn increases undesired gloss.", "In these cases it is desirable to use a low MFI polyethylene and a high level of crosslinking agent ELVALOY AS in order to obtain a sheet with low gloss, good embossing and low MFI.", "Thermoforming, however, suffers slightly due to the presence of two different polyolefins (polyethylene and polypropylene) with different melting temperatures." ]
[0001] This application is based on Japanese Patent Application No. 2002-349987 filed on Dec. 2, 2002, the contents of which are hereby incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a semiconductor integrated circuit device, and more particularly to a semiconductor integrated circuit device provided with a redundancy circuit. [0004] 2. Description of the Prior Art [0005] A semiconductor integrated circuit such as a memory usually incorporates a redundancy circuit by the use of which an effective circuit block is selected. This helps increase the yield of the product. FIG. 4 shows an example of the configuration of a conventional redundancy circuit. The redundancy circuit shown in FIG. 4 is composed of N+1 address program circuits AP 0 to APN and an AND circuit 14 that outputs, as a signal REDEN, the AND of the outputs of the individual address program circuits AP 0 to APN. Each address program circuit is composed of a MOSFET (metal-oxide semiconductor field-effect transistor), a fuse element, and a judgment circuit. [0006] Here, the configuration of the address program circuit AP 0 will be described. An n-channel MOSFET 11 receives a constant voltage Vcc at its source, receives a gate signal NEN at its gate, and has its drain grounded through a fuse element 12 . The node between the MOSFET 11 and the fuse element 12 is connected to a judgment circuit 13 . The judgment circuit 13 receives an input signal A( 0 ), and outputs an output signal PROG( 0 ) according to the potential at the node between the MOSFET 11 and the fuse element 12 . The other address program circuits AP 1 to APN are configured in the same manner as the address program circuit AP 0 , and therefore their configuration will not be discussed separately. [0007] The fuse elements provided in the address program circuits AP 0 to APN are typically “polyfuses”, i.e., fuse elements formed of polycrystalline silicon. FIG. 5 is a schematic sectional view of and around a polyfuse formed in a redundancy circuit. The polyfuse 16 is formed above a LOCOS (local oxidation of silicon) 15 , and is covered with a protective film (passivation) 17 from above. Moreover, a window 18 is formed to permit the polyfuse 16 to be cut easily with a laser beam. Furthermore, multilayer conductors 19 are formed in the protective film 17 . [0008] Which polyfuses 16 to cut is determined according to where a semiconductor integrated circuit has defects, and cutting the relevant polyfuses with a laser beam definitely set the output state of a redundancy circuit as shown in FIG. 4. [0009] However, in semiconductor integrated circuits, in particular in modern high-performance semiconductor integrated circuits, conductors tend to be laid in increasing numbers of layers. This trend has inevitably been increasing the thickness h of the protective film 17 (see FIG. 5), and thus has been making it increasingly difficult to cut the polyfuses 16 with a laser beam unless the windows are made accordingly large. As the number of conductor layers further increases in future, the windows need to be made increasingly small according to design rules, until eventually it becomes impossible to cut the polyfuses with existing laser equipment. [0010] Some redundancy circuits use, as fuse elements, metal fuses instead of polyfuses. In a redundancy circuit so configured, the metal fuses can be formed near the surface layer (top) of the protective film, and therefore, even as the number of conductor layers further increases and the thickness of the protective film increases, it does not become difficult to cut them with a laser beam. However, as compared with polyfuses, metal fuses are liable to cutting failure resulting from refusing or the like after cutting with a laser beam. This necessitates larger cutting windows than for polyfuses. [0011] Incidentally, Japanese Patent Registered No. 2845847 discloses a semiconductor integrated circuit incorporating a custom-made circuit portion that are so configured as to meet a user's requirements. However, this patent makes no mention of redundancy circuits or multilayer conductors. SUMMARY OF THE INVENTION [0012] An object of the present invention is to provide a semiconductor integrated circuit device that permits the output state of a redundancy circuit to be definitely set easily even with an increased number of conductor layers. [0013] To achieve the above object, a semiconductor integrated circuit device according to the present invention is provided with a first semiconductor chip having a nonvolatile memory for storing redundancy information, and a second semiconductor chip having a conversion circuit for converting the redundancy information output in the form of serial data from the nonvolatile memory into parallel data and a redundancy circuit of which the output state is definitely set by receiving the parallel data output from the conversion circuit. [0014] According to the present invention, a semiconductor integrated circuit device is provided with a first semiconductor chip having a nonvolatile memory for storing redundancy information, and a second semiconductor chip having a conversion circuit for converting the redundancy information output in the form of serial data from the nonvolatile memory into parallel data and a redundancy circuit of which the output state is definitely set by receiving the parallel data output from the conversion circuit. This makes it possible to definitely set the output state of the redundancy circuit without a laser beam. In this way, it is possible to realize a semiconductor integrated circuit device that permits the output state of a redundancy circuit to be definitely set easily even with an increased number of conductor layers. Moreover, there is no need to use laser equipment any longer. This helps simplify the manufacturing facilities. [0015] Moreover, according to the present invention, data transfer from the nonvolatile memory to the conversion circuit is achieved in the form of serial data. This helps reduce the number of connectors (for example, bumps) by way of which the nonvolatile memory and the conversion circuit are connected together. This helps reduce the size and cost of the semiconductor integrated circuit device as compared with in a case where data transfer from the nonvolatile memory to the conversion circuit is achieved in the form of parallel data. BRIEF DESCRIPTION OF THE DRAWINGS [0016] This and other objects and features of the present invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the accompanying drawings in which: [0017] [0017]FIG. 1 is a diagram showing the outer appearance of a semiconductor integrated circuit device according to the invention; [0018] [0018]FIG. 2 is a circuit block diagram of a principal portion of the semiconductor integrated circuit device according to the invention; [0019] [0019]FIG. 3 is a diagram showing an example of the circuit configuration of the serial-to-parallel conversion circuit and redundancy circuit provided in the semiconductor integrated circuit device according to the invention; [0020] [0020]FIG. 4 is a diagram showing an example of an outline of the configuration of the redundancy circuit provided in a conventional semiconductor integrated circuit device; and [0021] [0021]FIG. 5 is a sectional view of and around a polyfuse provided in the redundancy circuit shown in FIG. 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] [0022]FIG. 1 is an external view of a semiconductor integrated circuit device according to the present invention. A first semiconductor chip 1 and a second semiconductor chip 2 are connected together by way of bumps (not illustrated). The second semiconductor chip 2 has a memory IC, a memory circuit, and a CPU circuit previously incorporated in it to form a semiconductor integrated circuit (not illustrated) generally called an embedded IC. [0023] [0023]FIG. 2 is a circuit block diagram of a principal portion of the semiconductor integrated circuit device according to the invention. The semiconductor integrated circuit device according to the invention has a redundancy data loading control circuit 3 , a nonvolatile memory 4 , a serial-to-parallel conversion circuit 5 , a plurality of redundancy circuits 6 , and a plurality of functional circuits 7 , such as memories, having circuits that are individually selected or unselected by the redundancy circuits 6 . The nonvolatile memory 4 , such as a flash memory or EEPROM (electrically-erasable programmable read-only memory), is provided on the first semiconductor chip 1 (see FIG. 1), and the redundancy data loading control circuit 3 , the serial-to-parallel conversion circuit 5 , the redundancy circuits 6 , and the functional circuits 7 are provided on the second semiconductor chip 2 (see FIG. 1). The nonvolatile memory 4 is provided with connection terminals for connection to the redundancy data loading control circuit 3 , and these connection terminals are connected, by way of bumps (not illustrated), to the connection terminals provided in the redundancy data loading control circuit 3 . The nonvolatile memory 4 is also provided with connection terminals for connection to the serial-to-parallel conversion circuit 5 , and these connection terminals are connected, by way of bumps (not illustrated), to the connection terminals provided in the serial-to-parallel conversion circuit 5 . [0024] Redundancy information, i.e., information on the defects found in the functional circuits 7 provided on the second semiconductor chip 2 , is previously stored in the nonvolatile memory 4 . When electric power is supplied to the semiconductor integrated circuit device according to the invention, the redundancy data loading control circuit 3 feeds the nonvolatile memory 4 with operation commands, and controls the operation of the serial-to-parallel conversion circuit 5 . According to the operation commands fed from the redundancy data loading control circuit 3 by serial control, the nonvolatile memory 4 starts serial transfer of the previously stored redundancy information. Under the control of the redundancy data loading control circuit 3 , the serial-to-parallel conversion circuit 5 converts the serial data transferred from the nonvolatile memory 4 into parallel data, and feeds it to the individual redundancy circuits 6 . When the redundancy circuits 6 receive this parallel data, their output states are definitely set, with the result that, according to the thus definitely set data, some of the functional circuits 7 are selected and the others unselected. [0025] Here, the data transfer from the nonvolatile memory 4 provided on the first semiconductor chip 1 to the serial-to-parallel conversion circuit 5 provided on the second semiconductor chip 2 and the data transfer from the second semiconductor chip 2 to the first semiconductor chip 1 is achieved with serial data. This helps reduce the number of bumps by way of which the first and second semiconductor chips 1 and 2 are connected together. In general, as the number of bumps increases, the area of the pads required for them also increases. Accordingly, by reducing the number of bumps, it is possible to make the semiconductor integrated circuit device smaller. [0026] Next, the circuit configuration of the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 will be described. FIG. 3 shows an example of the circuit configuration of the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 . In FIG. 3, such signals as are found also in FIG. 4 are identified with the same reference symbols. Moreover, in FIG. 3, such circuit elements as are found also in FIG. 2 are identified with the same reference numerals. [0027] The serial-to-parallel conversion circuit 5 is composed of N+1 flip-flops FF 0 to FFN. The flip-flops FF 0 to FFN receive a clock signal CK at their clock terminals (C terminals). The clock signal CK is output from the redundancy data loading control circuit 3 (see FIG. 2). The data input terminal (D terminal) of the flip-flop FF 0 is connected to the non-inverting output terminal (Q terminal) of the flip-flop FF 1 and to a judgment circuit J 1 . Likewise, the data input terminal (D terminal) of the flip-flop FFk is connected to the non-inverting output terminal (Q terminal) of the flip-flop FFk+1 and to a judgment circuit Jk+1 (where k is a natural number in the range from 1 to N−1). The non-inverting output terminal (Q terminal) of the flip-flop FF 0 is connected to a judgment circuit J 0 , and the flip-flop FFN receives serial data S 0 at its data input terminal (D terminal). The serial data S 0 fed to the data input terminal (D terminal) of the flip-flop FFN is the serial data of redundancy information output from the nonvolatile memory 4 (see FIG. 2). [0028] The judgment circuit Jm receives an input signal A(m) and outputs an output signal PROG(m) according to the output of the flip-flop FFm (where m is an integer number in the range from 0 to N). An AND circuit 8 receives the outputs of the individual judgment circuits J 0 to JN, and outputs, as a signal REDEN, the AND of the outputs of the judgment circuits J 0 to JN. Thereafter, the semiconductor integrated circuit device performs normal operation. [0029] By configuring the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 as described above, it is possible to output the same signal REDEN as is output from the conventional redundancy circuit shown in FIG. 4. [0030] In the manufacturing process of the semiconductor integrated circuit according to the present invention, defects in the embedded circuits provided on the second semiconductor chip are detected through inspection using a tester or the like, and, on the basis of the results of the detection, redundancy information is created. The redundancy information is then stored in the nonvolatile memory 4 . Thereafter, with the nonvolatile memory, thus having the redundancy information stored therein, connected to the serial-to-parallel conversion circuit, inspection is performed by using a tester or the like to check whether or not the defects have been eliminated as expected. By contrast, in the manufacturing process of a semiconductor integrated circuit incorporating the conventional redundancy circuits shown in FIG. 4, defects in the semiconductor integrated circuit are detected by the use of electrical signals, and, on the basis of the results of the detection, redundancy information is created. Then, according to the redundancy information, fuse elements are cut with a laser beam. Thereafter, inspection is performed by using electrical signals or the like to check whether or not the defects have been eliminated as expected. In the manufacturing process of the semiconductor integrated circuit device according to the present invention, an extra step of connecting bumps together is required, but there is no need to use laser equipment to cut a large number of fuse elements or to form deep holes as windows as practiced in the manufacturing process of conventional semiconductor integrated circuits. This helps simplify the manufacturing facilities.
A conventional semiconductor integrated circuit device suffers from the increasing difficulty in definitely setting the output state of a redundancy circuit as the number of conductor layers increases. To overcome this inconvenience, according to the present invention, a semiconductor integrated circuit device has a first semiconductor chip having a nonvolatile memory for storing redundancy information, and has a second semiconductor chip having a conversion circuit for converting the redundancy information output in the form of serial data from the nonvolatile memory into parallel data and a redundancy circuit of which the output state is definitely set by receiving the parallel data output from the conversion circuit.
Summarize the document in concise, focusing on the main idea's functionality and advantages.
[ "[0001] This application is based on Japanese Patent Application No. 2002-349987 filed on Dec. 2, 2002, the contents of which are hereby incorporated by reference.", "BACKGROUND OF THE INVENTION [0002] 1.", "Field of the Invention [0003] The present invention relates to a semiconductor integrated circuit device, and more particularly to a semiconductor integrated circuit device provided with a redundancy circuit.", "[0004] 2.", "Description of the Prior Art [0005] A semiconductor integrated circuit such as a memory usually incorporates a redundancy circuit by the use of which an effective circuit block is selected.", "This helps increase the yield of the product.", "FIG. 4 shows an example of the configuration of a conventional redundancy circuit.", "The redundancy circuit shown in FIG. 4 is composed of N+1 address program circuits AP 0 to APN and an AND circuit 14 that outputs, as a signal REDEN, the AND of the outputs of the individual address program circuits AP 0 to APN.", "Each address program circuit is composed of a MOSFET (metal-oxide semiconductor field-effect transistor), a fuse element, and a judgment circuit.", "[0006] Here, the configuration of the address program circuit AP 0 will be described.", "An n-channel MOSFET 11 receives a constant voltage Vcc at its source, receives a gate signal NEN at its gate, and has its drain grounded through a fuse element 12 .", "The node between the MOSFET 11 and the fuse element 12 is connected to a judgment circuit 13 .", "The judgment circuit 13 receives an input signal A( 0 ), and outputs an output signal PROG( 0 ) according to the potential at the node between the MOSFET 11 and the fuse element 12 .", "The other address program circuits AP 1 to APN are configured in the same manner as the address program circuit AP 0 , and therefore their configuration will not be discussed separately.", "[0007] The fuse elements provided in the address program circuits AP 0 to APN are typically “polyfuses”, i.e., fuse elements formed of polycrystalline silicon.", "FIG. 5 is a schematic sectional view of and around a polyfuse formed in a redundancy circuit.", "The polyfuse 16 is formed above a LOCOS (local oxidation of silicon) 15 , and is covered with a protective film (passivation) 17 from above.", "Moreover, a window 18 is formed to permit the polyfuse 16 to be cut easily with a laser beam.", "Furthermore, multilayer conductors 19 are formed in the protective film 17 .", "[0008] Which polyfuses 16 to cut is determined according to where a semiconductor integrated circuit has defects, and cutting the relevant polyfuses with a laser beam definitely set the output state of a redundancy circuit as shown in FIG. 4. [0009] However, in semiconductor integrated circuits, in particular in modern high-performance semiconductor integrated circuits, conductors tend to be laid in increasing numbers of layers.", "This trend has inevitably been increasing the thickness h of the protective film 17 (see FIG. 5), and thus has been making it increasingly difficult to cut the polyfuses 16 with a laser beam unless the windows are made accordingly large.", "As the number of conductor layers further increases in future, the windows need to be made increasingly small according to design rules, until eventually it becomes impossible to cut the polyfuses with existing laser equipment.", "[0010] Some redundancy circuits use, as fuse elements, metal fuses instead of polyfuses.", "In a redundancy circuit so configured, the metal fuses can be formed near the surface layer (top) of the protective film, and therefore, even as the number of conductor layers further increases and the thickness of the protective film increases, it does not become difficult to cut them with a laser beam.", "However, as compared with polyfuses, metal fuses are liable to cutting failure resulting from refusing or the like after cutting with a laser beam.", "This necessitates larger cutting windows than for polyfuses.", "[0011] Incidentally, Japanese Patent Registered No. 2845847 discloses a semiconductor integrated circuit incorporating a custom-made circuit portion that are so configured as to meet a user's requirements.", "However, this patent makes no mention of redundancy circuits or multilayer conductors.", "SUMMARY OF THE INVENTION [0012] An object of the present invention is to provide a semiconductor integrated circuit device that permits the output state of a redundancy circuit to be definitely set easily even with an increased number of conductor layers.", "[0013] To achieve the above object, a semiconductor integrated circuit device according to the present invention is provided with a first semiconductor chip having a nonvolatile memory for storing redundancy information, and a second semiconductor chip having a conversion circuit for converting the redundancy information output in the form of serial data from the nonvolatile memory into parallel data and a redundancy circuit of which the output state is definitely set by receiving the parallel data output from the conversion circuit.", "[0014] According to the present invention, a semiconductor integrated circuit device is provided with a first semiconductor chip having a nonvolatile memory for storing redundancy information, and a second semiconductor chip having a conversion circuit for converting the redundancy information output in the form of serial data from the nonvolatile memory into parallel data and a redundancy circuit of which the output state is definitely set by receiving the parallel data output from the conversion circuit.", "This makes it possible to definitely set the output state of the redundancy circuit without a laser beam.", "In this way, it is possible to realize a semiconductor integrated circuit device that permits the output state of a redundancy circuit to be definitely set easily even with an increased number of conductor layers.", "Moreover, there is no need to use laser equipment any longer.", "This helps simplify the manufacturing facilities.", "[0015] Moreover, according to the present invention, data transfer from the nonvolatile memory to the conversion circuit is achieved in the form of serial data.", "This helps reduce the number of connectors (for example, bumps) by way of which the nonvolatile memory and the conversion circuit are connected together.", "This helps reduce the size and cost of the semiconductor integrated circuit device as compared with in a case where data transfer from the nonvolatile memory to the conversion circuit is achieved in the form of parallel data.", "BRIEF DESCRIPTION OF THE DRAWINGS [0016] This and other objects and features of the present invention will become clear from the following description, taken in conjunction with the preferred embodiments with reference to the accompanying drawings in which: [0017] [0017 ]FIG. 1 is a diagram showing the outer appearance of a semiconductor integrated circuit device according to the invention;", "[0018] [0018 ]FIG. 2 is a circuit block diagram of a principal portion of the semiconductor integrated circuit device according to the invention;", "[0019] [0019 ]FIG. 3 is a diagram showing an example of the circuit configuration of the serial-to-parallel conversion circuit and redundancy circuit provided in the semiconductor integrated circuit device according to the invention;", "[0020] [0020 ]FIG. 4 is a diagram showing an example of an outline of the configuration of the redundancy circuit provided in a conventional semiconductor integrated circuit device;", "and [0021] [0021 ]FIG. 5 is a sectional view of and around a polyfuse provided in the redundancy circuit shown in FIG. 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] [0022 ]FIG. 1 is an external view of a semiconductor integrated circuit device according to the present invention.", "A first semiconductor chip 1 and a second semiconductor chip 2 are connected together by way of bumps (not illustrated).", "The second semiconductor chip 2 has a memory IC, a memory circuit, and a CPU circuit previously incorporated in it to form a semiconductor integrated circuit (not illustrated) generally called an embedded IC.", "[0023] [0023 ]FIG. 2 is a circuit block diagram of a principal portion of the semiconductor integrated circuit device according to the invention.", "The semiconductor integrated circuit device according to the invention has a redundancy data loading control circuit 3 , a nonvolatile memory 4 , a serial-to-parallel conversion circuit 5 , a plurality of redundancy circuits 6 , and a plurality of functional circuits 7 , such as memories, having circuits that are individually selected or unselected by the redundancy circuits 6 .", "The nonvolatile memory 4 , such as a flash memory or EEPROM (electrically-erasable programmable read-only memory), is provided on the first semiconductor chip 1 (see FIG. 1), and the redundancy data loading control circuit 3 , the serial-to-parallel conversion circuit 5 , the redundancy circuits 6 , and the functional circuits 7 are provided on the second semiconductor chip 2 (see FIG. 1).", "The nonvolatile memory 4 is provided with connection terminals for connection to the redundancy data loading control circuit 3 , and these connection terminals are connected, by way of bumps (not illustrated), to the connection terminals provided in the redundancy data loading control circuit 3 .", "The nonvolatile memory 4 is also provided with connection terminals for connection to the serial-to-parallel conversion circuit 5 , and these connection terminals are connected, by way of bumps (not illustrated), to the connection terminals provided in the serial-to-parallel conversion circuit 5 .", "[0024] Redundancy information, i.e., information on the defects found in the functional circuits 7 provided on the second semiconductor chip 2 , is previously stored in the nonvolatile memory 4 .", "When electric power is supplied to the semiconductor integrated circuit device according to the invention, the redundancy data loading control circuit 3 feeds the nonvolatile memory 4 with operation commands, and controls the operation of the serial-to-parallel conversion circuit 5 .", "According to the operation commands fed from the redundancy data loading control circuit 3 by serial control, the nonvolatile memory 4 starts serial transfer of the previously stored redundancy information.", "Under the control of the redundancy data loading control circuit 3 , the serial-to-parallel conversion circuit 5 converts the serial data transferred from the nonvolatile memory 4 into parallel data, and feeds it to the individual redundancy circuits 6 .", "When the redundancy circuits 6 receive this parallel data, their output states are definitely set, with the result that, according to the thus definitely set data, some of the functional circuits 7 are selected and the others unselected.", "[0025] Here, the data transfer from the nonvolatile memory 4 provided on the first semiconductor chip 1 to the serial-to-parallel conversion circuit 5 provided on the second semiconductor chip 2 and the data transfer from the second semiconductor chip 2 to the first semiconductor chip 1 is achieved with serial data.", "This helps reduce the number of bumps by way of which the first and second semiconductor chips 1 and 2 are connected together.", "In general, as the number of bumps increases, the area of the pads required for them also increases.", "Accordingly, by reducing the number of bumps, it is possible to make the semiconductor integrated circuit device smaller.", "[0026] Next, the circuit configuration of the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 will be described.", "FIG. 3 shows an example of the circuit configuration of the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 .", "In FIG. 3, such signals as are found also in FIG. 4 are identified with the same reference symbols.", "Moreover, in FIG. 3, such circuit elements as are found also in FIG. 2 are identified with the same reference numerals.", "[0027] The serial-to-parallel conversion circuit 5 is composed of N+1 flip-flops FF 0 to FFN.", "The flip-flops FF 0 to FFN receive a clock signal CK at their clock terminals (C terminals).", "The clock signal CK is output from the redundancy data loading control circuit 3 (see FIG. 2).", "The data input terminal (D terminal) of the flip-flop FF 0 is connected to the non-inverting output terminal (Q terminal) of the flip-flop FF 1 and to a judgment circuit J 1 .", "Likewise, the data input terminal (D terminal) of the flip-flop FFk is connected to the non-inverting output terminal (Q terminal) of the flip-flop FFk+1 and to a judgment circuit Jk+1 (where k is a natural number in the range from 1 to N−1).", "The non-inverting output terminal (Q terminal) of the flip-flop FF 0 is connected to a judgment circuit J 0 , and the flip-flop FFN receives serial data S 0 at its data input terminal (D terminal).", "The serial data S 0 fed to the data input terminal (D terminal) of the flip-flop FFN is the serial data of redundancy information output from the nonvolatile memory 4 (see FIG. 2).", "[0028] The judgment circuit Jm receives an input signal A(m) and outputs an output signal PROG(m) according to the output of the flip-flop FFm (where m is an integer number in the range from 0 to N).", "An AND circuit 8 receives the outputs of the individual judgment circuits J 0 to JN, and outputs, as a signal REDEN, the AND of the outputs of the judgment circuits J 0 to JN.", "Thereafter, the semiconductor integrated circuit device performs normal operation.", "[0029] By configuring the serial-to-parallel conversion circuit 5 and the redundancy circuits 6 as described above, it is possible to output the same signal REDEN as is output from the conventional redundancy circuit shown in FIG. 4. [0030] In the manufacturing process of the semiconductor integrated circuit according to the present invention, defects in the embedded circuits provided on the second semiconductor chip are detected through inspection using a tester or the like, and, on the basis of the results of the detection, redundancy information is created.", "The redundancy information is then stored in the nonvolatile memory 4 .", "Thereafter, with the nonvolatile memory, thus having the redundancy information stored therein, connected to the serial-to-parallel conversion circuit, inspection is performed by using a tester or the like to check whether or not the defects have been eliminated as expected.", "By contrast, in the manufacturing process of a semiconductor integrated circuit incorporating the conventional redundancy circuits shown in FIG. 4, defects in the semiconductor integrated circuit are detected by the use of electrical signals, and, on the basis of the results of the detection, redundancy information is created.", "Then, according to the redundancy information, fuse elements are cut with a laser beam.", "Thereafter, inspection is performed by using electrical signals or the like to check whether or not the defects have been eliminated as expected.", "In the manufacturing process of the semiconductor integrated circuit device according to the present invention, an extra step of connecting bumps together is required, but there is no need to use laser equipment to cut a large number of fuse elements or to form deep holes as windows as practiced in the manufacturing process of conventional semiconductor integrated circuits.", "This helps simplify the manufacturing facilities." ]
BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a transceiver. The mobile radio system Global System for Mobile Communication (GSM), which is widely used today, will be replaced by a third-generation mobile radio system for technological and economic reasons. This system is known by the name of Universal Mobile Telecommunications System (UMTS), in Europe and as International Mobile Telecommunication System (IMT) 2000, internationally. UMTS or IMT 2000, respectively, is intended to provide for a much higher data transmission capacity than GSM and to create an international standard. A system that is capable of transmitting and receiving simultaneously is called a full duplex system. Systems are also capable of full duplex if transmitting and receiving do not take place simultaneously but the switchover between the two phases is unnoticed by the subscriber. A distinction is made between two fundamental duplex methods: frequency division duplex (FDD) in which transmitting and receiving take place in different frequency bands which are correspondingly separated and time division duplex (TDD) in which the two directions of transmission are separated in different time slots. In general, transmitting from a mobile station to a base station or fixed station is called an uplink and a transmission from the base station or fixed station to the mobile station is called a downlink. In TDD, transmitting and receiving frequencies are the same. In UMTS a duplex frequency of 190 megahertz is provided for FDD with a fixed duplex frequency. Apart from the TDD and FDD transmissions described, an additional FDD with a variable duplex frequency, which can be between 134.8 and 245.2 megahertz, is provided in the UMTS. The duplex frequency is here the frequency spacing between the transmitting and receiving frequency. The UMTS specification provides two frequency bands from 1900 to 1920 megahertz and from 2010 to 2025 megahertz for TDD transmission. FDD transmission with a fixed duplex spacing of 190 megahertz is provided in a transmitting band from 1920 to 1980 and a receiving band from 2110 to 2170 megahertz. Compared with the fixed correlation between two channels, namely one uplink and one downlink channel in each case, which is usual with TDD and FDD with fixed duplex frequency, an asymmetric data transmission in which, for example, two downlink channels can be combined with one uplink channel is possible with variable-frequency FDD. In known IMT 2000 transceivers, a transmitting intermediate frequency of 380 megahertz and a receiving intermediate frequency of 190 megahertz is normally used. In UMTS, however, the 380 megahertz intermediate frequency must be up-converted to approximately 2 gigahertz as a result of which the local oscillator frequency needed falls into the known Industrial Scientific and Medical (ISM) band, which is approximately 2.4 gigahertz. However, this band is used for forming wireless peripheral interfaces in the so-called Bluetooth standard. Since Bluetooth interfaces should be capable of being integrated into mobile telephones which have transceivers, interference is to be expected if a 380 MHz intermediate frequency is used. In the Gigahertz-Radio-Frontend project GIRAFE, a receiver having an intermediate frequency of 0 megahertz is proposed for a UMTS system. Please refer to the following Internet page http://[email protected]/acts/analysys/concertation/mobility/girafe.htm. SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide a transceiver that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which is suitable for the duplex methods FDD, TDD and FDD with variable frequency spacing and which has a low power requirement and is also suitable for large-scale integration. With the foregoing and other objects in view there is provided, in accordance with the invention, a transceiver containing a transmitting branch, a receiving branch, and a duplex unit connected to the transmitting branch, to the receiving branch and to be connected to an antenna. The duplex unit separates the transmitting branch from the receiving branch. A first mixer is provided and has an output and an input connected to the receiving branch. A first local oscillator is connected to the first mixer. A receiving intermediate-frequency path is connected to the output of the first mixer. The receiving intermediate-frequency path has an intermediate-frequency in a range of 0 to 0.5 megahertz. A second mixer is provided and has an input and an output connected to the transmitting branch. A transmitting intermediate-frequency path is connected to the input of the second mixer. The transmitting intermediate-frequency path has an intermediate-frequency in a range of 180 megahertz to 200 megahertz. A second local oscillator is connected to the second mixer. Compared with existing IMT 2000 transceiver concepts with a receiver intermediate frequency of 190 megahertz which is very close to normal television frequencies, the configuration described, with a receiving intermediate frequency in a range from 0 to 0.5 megahertz, has the advantage that the possibility of injecting television transmission frequencies is reduced. This is of special significance in the case of UMTS receivers which have a very high receiving sensitivity. Since an intermediate frequency in a range from 0 to 0.5 megahertz is provided in the receiver, the power consumption is low. A receiver which has an intermediate frequency in a range from 0 to 0.5 megahertz does not need an image frequency filter. This simplifies the structure of the transceiver. Having the receiving intermediate frequency in a range from 0 to 0.5 megahertz provides for a maximum of flexibility with respect to the integration of other mobile radio systems. If a code division multiple access (CDMA) subscriber separation is used in which AC coupling is allowed, the DC offset problems which usually afflict 0-megahertz intermediate-frequency receivers are largely suppressed. Furthermore, the integration of the first local oscillator in the transceiver reduces problems with respect to auto-mixing in the local oscillator. Overall, the configuration described provides for a maximum of integration capability. Compared with the 380 megahertz known for IMT 2000, the transmitting intermediate frequency of 190 megahertz +/−5 megahertz or +/−10 megahertz leads to a much lower power consumption. Since, in mobile radio, transceivers are normally used in mobile telephones that should be particularly small and of light weight, this feature is especially advantageous. If, in the case of FDD with variable frequency spacing, the deviation of the frequency spacing from 190 megahertz is less than or equal to +/−10 megahertz, a common first local oscillator can perform both the conversion of the receiving frequency into the receiver intermediate frequency and the conversion of the transmitter intermediate frequency into the transmitting frequency. This further reduces power consumption and space requirement of the transceiver and interference signals. Since, in practical mobile radios, there are a number of network operators among which the existing bandwidth of the network or, respectively, of the transmission channels must be divided, it is conceivable that an individual network operator only receives 15 megahertz bandwidths in the UMTS system. In the case of FDD with variable duplex spacing, the duplex frequency is therefore limited to 190 megahertz +/−5 megahertz or +/−10 megahertz, respectively. It is therefore advantageous to vary the transmitting intermediate frequency in such a manner that it is either 180 or 185 or 190 or 195 or 200 megahertz. In this case, only one local oscillator or, respectively, voltage-controlled oscillator is capable of providing the requirements of the frequency duplex method with variable duplex frequency for a network operator which only has a limited bandwidth available. This makes it possible to have an FDD operation with variable duplex frequency with low power consumption and a low number of interference signals. In an advantageous embodiment of the present invention, a first changeover switch is provided by which it is possible to connect the first local oscillator or a further local oscillator to the second mixer. For an FDD operation with variable duplex frequency which only slightly deviates from the fixed duplex frequency, the power-saving operation with a single first local oscillator which is connected to the first mixer and to the second mixer is sufficient. If, however, it is intended to exploit the full spectrum of the FDD with variable frequency spacing from 134.8 to 245.2 megahertz, the second mixer can be switched to the further local oscillator. To prevent unwanted signals that are caused by the operation of two local oscillators which have closely adjacent frequencies of oscillation and by nonlinearities in the transceiver, the further local oscillator should have a frequency of oscillation which is below the transmitting frequency of the transceiver. As a result, the further local oscillator will not interfere with the first local oscillator as a result of which both local oscillators can be integrated in a common IC. In a further advantageous embodiment of the present invention, a baseband unit, to which the transmitting and receiving intermediate-frequency paths are connected, has a digital mixer which can be detuned in steps of 200 kilohertz. The digital mixer performs a frequency correction of +/−200 or, respectively, +/−400 kilohertz as deviation from the fixed duplex frequency of 190 megahertz. This two-step tuning solution has the advantage that the radio-frequency phase-locked loops can operate with steps of 1 megahertz in the first and further local oscillator. This reduces the multiplication of the phase noise in the phase-locked loops so that the requirements for phase detectors or charge pumps can be relaxed and the power consumption can thus be reduced. For example, the multiplication of the phase noise is reduced by a factor of 20* log (5) in the case of 1 megahertz steps in the phase detector. As a result, it will also be possible for the switchover of the phase-locked loop to be faster. The time for a frequency search in the UMTS system is reduced by a factor of 4 due to the fact that the switching times in the digital mixer are distinctly shorter in comparison with a phase-locked loop. The capacitances in the phase-locked loop can be smaller which results in additional advantages in the integration. Should 100 kilohertz frequency steps be needed in future due to changes in the UMTS specification, these can be implemented more easily in the digital mixer than in phase-locked loops. In accordance with an added feature of the invention, a third mixer is connected to the second mixer, a digital-to-analog converter is connected to the third mixer, and a third local oscillator is connected to the third mixer. In accordance with an additional feature of the invention, the first local oscillator, the second local oscillator and the third local oscillator in each case have a voltage-controlled oscillator and a phase-locked loop. In accordance with a further feature of the invention, the transceiver is a universal mobile telecommunications system transceiver, and the duplex unit has a frequency splitter and a switch connected to the frequency splitter. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a transceiver, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified block diagram of a transceiver according to the invention; and FIG. 2 is a block diagram of a second embodiment of the transceiver according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a transceiver containing a duplex unit DE, which is connected to a transmitting and receiving antenna A. The duplex unit separates a transmitting branch T from a receiving branch R at this radio-frequency level. The receiving branch R exhibits a low-noise preamplifier LNA which is constructed to be controllable. The receiving branch R is connected to a first mixer M 1 that is connected to a first local oscillator LO 1 through a third switch SW 3 . In the first mixer M 1 , a received signal is down-converted to an intermediate-frequency level with a local-oscillator signal. The first mixer M 1 is connected to a receiving intermediate-frequency path RI that has an amplifier V 3 which is constructed to be controllable. The receiving intermediate-frequency path is followed by an analog/digital converter AD and a first digital mixer DM 1 . This is used for detuning the frequency in the receiving intermediate-frequency path RI in steps of 200 kilohertz. Other modules usually provided in a transceiver such as, for example, voice decoding are not drawn in FIG. 1 . The transmitting branch T exhibits a transmitting amplifier PA that is controllable and is connected to a second mixer M 2 . A transmitting intermediate-frequency path TI connected to the second mixer M 2 can exhibit an intermediate-frequency signal that is mixed with a local oscillator signal to form the desired transmitting frequency. The transmitting intermediate-frequency path TI exhibits a band-pass filter BP that has a mean frequency of 190 megahertz at an intermediate frequency of 190 megahertz in the transmitter. The pass band of the band-pass filter BP extends from 180 to 200 megahertz. A second local oscillator LO 2 is connected to a third mixer M 3 that is connected to the transmitting intermediate-frequency path TI. Furthermore, the third mixer M 3 is connected to a digital/analog converter chip DA, which is connected to a second digital mixer DM 2 for detuning the transmitting baseband frequency in 200 kilohertz steps. The third mixer M 3 is used for up-converting a baseband signal to an intermediate-frequency level by use of a second frequency of oscillation. The first and the second digital mixer DM 1 , DM 2 are also used for automatic frequency control (AFC) in the baseband. For this purpose, any frequency from 0.1 hertz up to half the clock frequency of the mixers can be set by the digital mixers. In the UMTS specification, a frequency pattern with steps of 200 kilohertz is described for transmitting and receiving. Together with synthesizers disposed in the local oscillators LO 1 , LO 1 ′, LO 2 and having a step length of 1 megahertz, any UMTS frequency can be advantageously set in a 200-kilohertz pattern by detuning the digital mixers by +/−200 kilohertz or by +/−400 kilohertz. For FDD operations with a variable duplex frequency which has a large deviation from the fixed duplex frequency of 190 megahertz, a first changeover switch SW 1 can be provided for switching the connection of the second mixer M 2 to the first local oscillator to another local oscillator LO 1 ′. Using the third switch SW 3 , the first mixer M 1 can be switched from the first local oscillator LO 1 ′ to the second local oscillator LO 2 . This is advantageous, in particular, for TDD reception since the frequencies of the first and of the further local oscillator LO 1 , LO 1 ′ differ distinctly from the required TDD receiving intermediate frequency in this case whereas the latter overlaps the frequency range of the second local oscillator when this corresponds to seven times the transmitting intermediate frequency and the doubled TDD receiving frequency can be generated by multiplying the frequency of the second local oscillator LO 2 by a factor of three. Since FDD or, respectively, TDD transmitting and TDD receiving do not take place simultaneously, the second local oscillator can support both operating modes. The first local oscillator LO 1 , the second local oscillator LO 2 and the further local oscillator LO 1 ′ are connected to a common reference oscillator XO. The configuration described has the advantage that the local oscillators have only a small tuning range. As a result, they are improved with respect to phase noise, sensitivity, substrate noise and response. Since, initially, full network coverage will not be guaranteed on introduction of the UMTS system and since, at the same time, the existing GSM networks offer almost all coverage, it is advantageous that UMTS transceivers are capable of monitoring the availability and the quality of the GSM channels in the case of poor UMTS reception. A special operating method, the so-called slotted mode, is provided for this purpose. This exhibits time gaps in the transmission during which the GSM channels can be monitored. To keep the transmission rate constant, the data must be compressed preceding the gaps. The so-called compressed mode is provided for this purpose. However, this reduces the network capacity. The slotted mode is provided for monitoring GSM 1800 channels whereas GSM 900 channels, that is to say GSM reception, can be simultaneously monitored with UMTS transmission. The first and the second local oscillators LO 1 , LO 2 are used for this UMTS transmission while at the same time the further local oscillator LO 1 ′ is used for GSM reception. For this purpose, a fourth switch SW 4 is provided which can switch the further local oscillator LO 1 ′ through to a GSM transceiver. For better clarity, a table containing the frequency ranges of the local oscillators in megahertz (third and fourth row) and the respective transmitting and receiving modes (first column) is specified. An X here indicates an active local oscillator. Tx stands for transmit and Rx for receive. Local oscillator LO1 LO2 LO1′ Operating mode TDD GSM GSM Rx 900 Rx 1800 Rx Frequency range in MHz 4184 1330 3800 3464 3700 3610 to +/−70 to to to to 4426 4050 3840 3840 3760 FDD Fixed duplex Tx X X FDD Fixed duplex Rx X FDD Var. duplex +/−5, +/−10 MHz Tx X X FDD Var. duplex +/−5, +/−10 MHz Rx X FDD Var. duplex 134.8-245.2 MHz Tx X X FDD Var. duplex 134.8-245.2 MHz Rx X TDD Tx X X TDD Rx X FDD standby Rx X TDD standby Rx X UMTS FDD transmit Tx X X GSM receive Rx X UMTS TDD transmit Tx X X GSM receive Rx X The frequency range of the second local oscillator LO 2 in FDD mode from 1260 to 1400 megahertz corresponds to seven times the transmitting intermediate frequency which is in a range from 180 megahertz to 200 megahertz. The frequency range of the second local oscillator LO 2 for the TDD operating mode is in the range of the third harmonic of the frequency range of the second local oscillator LO 2 in FDD mode. For GSM 900, that is to say a GSM system in the 900 megahertz band, a local oscillator frequency of from 3700 to 3840 megahertz is required with a receiving band from 925 to 960 megahertz and four times the frequency. For GSM 1800, that is to say a GSM system in the 1800 megahertz band, a local oscillator frequency of from 3610 to 3760 megahertz is required with a receiving band from 1805 to 1880 megahertz and twice the frequency. The exemplary embodiment according to FIG. 1 has the advantage that operation is possible both with time division duplex, frequency division duplex with fixed duplex frequency and frequency division duplex with variable duplex frequency. The simple structure and the high integration capability are the result of the receiving intermediate frequency in a range from 0 to 0.5 megahertz and the transmitting intermediate frequency of 190 megahertz. The lower transmitting and receiving intermediate frequencies compared with known IMT 2000 transceivers and the possible operation using only one first local oscillator LO 1 ensure low power consumption. FIG. 2 shows a second exemplary embodiment containing the duplex unit DE which has a frequency splitter DUP and a switch SW 2 . The frequency splitter DUP separates the FDD downlink band that is supplied to a first low-noise preamplifier LNA 1 from FDD uplink and TDD bands by a suitable choice of transmitting and receiving filters. Transmission and reception in TDD mode are separated in the second switch SW 2 . The second low-noise preamplifier LNA 2 is used for amplifying in TDD receiving mode. The band-pass filters BP 1 , BP 2 following the low-noise preamplifiers LNA 1 , LNA 2 are adapted to the respective receiving frequency bands and to the amplifiers V 1 , V 2 following them. To convert the receiving frequencies into an intermediate frequency of 0 megahertz, two first mixers M 1 , M 1 ′ are provided, which are in each case followed by a low-pass filter TP 1 , TP 1 ′. The first mixers M 1 , M 1 ′ are supplied with a halved first local oscillator frequency LO 1 which is generated in a first local oscillator LO 1 and amplified in an amplifier V 6 . The intermediate-frequency signals are supplied to an A/D converter AD, AD′ from additional amplifiers V 3 , V 3 ′ followed by low-pass filters TP 2 , TP 2 ′ in which a DC offset compensation is performed by a compensator DC. AC coupling is possible as an alternative to this DC offset compensation. At the transmitting end T, a directional filter FI preceded by a controllable power amplifier PA and a band-pass filter BP 5 is connected to the duplex unit DE. These are preceded by a gain-controlled amplifier AGC 2 . A second mixer M 2 which up-converts the transmitting intermediate frequency to the respective desired transmitting frequency by using a local oscillator frequency is connected via a further band-pass filter BP 4 . The first switch SW 1 can switch the frequency of oscillation to be supplied to the second mixer M 2 via a divider V 5 which divides by two, between the first local oscillator LO 1 and the further local oscillator LO 1 ′. The second mixer M 2 is preceded by third mixers M 3 , M 3 ′ which up-convert signals conditioned in digital/analog converters DA, DA′ and low-pass filters TP 3 , TP 3 ′ to the transmitting intermediate frequency by the second local oscillator LO 2 . An amplifier V 4 , a band-pass filter BP 3 and a gain-controlled amplifier AGC 1 are provided between the second and third mixer M 2 , M 3 in the transmitting intermediate-frequency path TI. The local oscillators LO 1 , LO 1 ′, LO 2 in each case have a phase-locked loop PLL 1 , PLL 1 ′, PLL 2 and a voltage-controlled oscillator VCO 1 , VCO 1 ′, VCO 2 . The circuit configuration of the transceiver according to FIG. 2 provides for operation with frequency division duplex with a fixed duplex frequency, frequency division duplex with a variable duplex frequency and time division duplex. If a narrow bandwidth of, for example, 15 megahertz is available to a network operator in the UMTS system, an energy-saving FDD mode with variable duplex frequency using only one first local oscillator LO 1 which is connected to first and second mixers M 1 , M 2 can be effected with the present transceiver. The circuit configuration described provides for a high-density integration.
A transceiver for use in universal mobile telecommunication systems is specified which exhibits an intermediate frequency in a range from 0 to 0.5 megahertz at the receiver end and an intermediate frequency of 190 megahertz at the transmitting end. The configuration described enables it to be operated with frequency duplex division (FDD), time duplex division and FDD variable duplex frequency. When a network operator is only provided with a narrow bandwidth, the configuration described can be operated in a particularly energy-saving manner due to the fact that only one local oscillator is needed for the first and second mixers. In this case, the transmit intermediate frequency of 190 megahertz can be adjusted by +/−5 or +/−10 megahertz. The configuration described can be highly integrated in a simple manner.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a transceiver.", "The mobile radio system Global System for Mobile Communication (GSM), which is widely used today, will be replaced by a third-generation mobile radio system for technological and economic reasons.", "This system is known by the name of Universal Mobile Telecommunications System (UMTS), in Europe and as International Mobile Telecommunication System (IMT) 2000, internationally.", "UMTS or IMT 2000, respectively, is intended to provide for a much higher data transmission capacity than GSM and to create an international standard.", "A system that is capable of transmitting and receiving simultaneously is called a full duplex system.", "Systems are also capable of full duplex if transmitting and receiving do not take place simultaneously but the switchover between the two phases is unnoticed by the subscriber.", "A distinction is made between two fundamental duplex methods: frequency division duplex (FDD) in which transmitting and receiving take place in different frequency bands which are correspondingly separated and time division duplex (TDD) in which the two directions of transmission are separated in different time slots.", "In general, transmitting from a mobile station to a base station or fixed station is called an uplink and a transmission from the base station or fixed station to the mobile station is called a downlink.", "In TDD, transmitting and receiving frequencies are the same.", "In UMTS a duplex frequency of 190 megahertz is provided for FDD with a fixed duplex frequency.", "Apart from the TDD and FDD transmissions described, an additional FDD with a variable duplex frequency, which can be between 134.8 and 245.2 megahertz, is provided in the UMTS.", "The duplex frequency is here the frequency spacing between the transmitting and receiving frequency.", "The UMTS specification provides two frequency bands from 1900 to 1920 megahertz and from 2010 to 2025 megahertz for TDD transmission.", "FDD transmission with a fixed duplex spacing of 190 megahertz is provided in a transmitting band from 1920 to 1980 and a receiving band from 2110 to 2170 megahertz.", "Compared with the fixed correlation between two channels, namely one uplink and one downlink channel in each case, which is usual with TDD and FDD with fixed duplex frequency, an asymmetric data transmission in which, for example, two downlink channels can be combined with one uplink channel is possible with variable-frequency FDD.", "In known IMT 2000 transceivers, a transmitting intermediate frequency of 380 megahertz and a receiving intermediate frequency of 190 megahertz is normally used.", "In UMTS, however, the 380 megahertz intermediate frequency must be up-converted to approximately 2 gigahertz as a result of which the local oscillator frequency needed falls into the known Industrial Scientific and Medical (ISM) band, which is approximately 2.4 gigahertz.", "However, this band is used for forming wireless peripheral interfaces in the so-called Bluetooth standard.", "Since Bluetooth interfaces should be capable of being integrated into mobile telephones which have transceivers, interference is to be expected if a 380 MHz intermediate frequency is used.", "In the Gigahertz-Radio-Frontend project GIRAFE, a receiver having an intermediate frequency of 0 megahertz is proposed for a UMTS system.", "Please refer to the following Internet page http://www.", "infowin.org/acts/analysys/concertation/mobility/girafe.", "htm.", "SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide a transceiver that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which is suitable for the duplex methods FDD, TDD and FDD with variable frequency spacing and which has a low power requirement and is also suitable for large-scale integration.", "With the foregoing and other objects in view there is provided, in accordance with the invention, a transceiver containing a transmitting branch, a receiving branch, and a duplex unit connected to the transmitting branch, to the receiving branch and to be connected to an antenna.", "The duplex unit separates the transmitting branch from the receiving branch.", "A first mixer is provided and has an output and an input connected to the receiving branch.", "A first local oscillator is connected to the first mixer.", "A receiving intermediate-frequency path is connected to the output of the first mixer.", "The receiving intermediate-frequency path has an intermediate-frequency in a range of 0 to 0.5 megahertz.", "A second mixer is provided and has an input and an output connected to the transmitting branch.", "A transmitting intermediate-frequency path is connected to the input of the second mixer.", "The transmitting intermediate-frequency path has an intermediate-frequency in a range of 180 megahertz to 200 megahertz.", "A second local oscillator is connected to the second mixer.", "Compared with existing IMT 2000 transceiver concepts with a receiver intermediate frequency of 190 megahertz which is very close to normal television frequencies, the configuration described, with a receiving intermediate frequency in a range from 0 to 0.5 megahertz, has the advantage that the possibility of injecting television transmission frequencies is reduced.", "This is of special significance in the case of UMTS receivers which have a very high receiving sensitivity.", "Since an intermediate frequency in a range from 0 to 0.5 megahertz is provided in the receiver, the power consumption is low.", "A receiver which has an intermediate frequency in a range from 0 to 0.5 megahertz does not need an image frequency filter.", "This simplifies the structure of the transceiver.", "Having the receiving intermediate frequency in a range from 0 to 0.5 megahertz provides for a maximum of flexibility with respect to the integration of other mobile radio systems.", "If a code division multiple access (CDMA) subscriber separation is used in which AC coupling is allowed, the DC offset problems which usually afflict 0-megahertz intermediate-frequency receivers are largely suppressed.", "Furthermore, the integration of the first local oscillator in the transceiver reduces problems with respect to auto-mixing in the local oscillator.", "Overall, the configuration described provides for a maximum of integration capability.", "Compared with the 380 megahertz known for IMT 2000, the transmitting intermediate frequency of 190 megahertz +/−5 megahertz or +/−10 megahertz leads to a much lower power consumption.", "Since, in mobile radio, transceivers are normally used in mobile telephones that should be particularly small and of light weight, this feature is especially advantageous.", "If, in the case of FDD with variable frequency spacing, the deviation of the frequency spacing from 190 megahertz is less than or equal to +/−10 megahertz, a common first local oscillator can perform both the conversion of the receiving frequency into the receiver intermediate frequency and the conversion of the transmitter intermediate frequency into the transmitting frequency.", "This further reduces power consumption and space requirement of the transceiver and interference signals.", "Since, in practical mobile radios, there are a number of network operators among which the existing bandwidth of the network or, respectively, of the transmission channels must be divided, it is conceivable that an individual network operator only receives 15 megahertz bandwidths in the UMTS system.", "In the case of FDD with variable duplex spacing, the duplex frequency is therefore limited to 190 megahertz +/−5 megahertz or +/−10 megahertz, respectively.", "It is therefore advantageous to vary the transmitting intermediate frequency in such a manner that it is either 180 or 185 or 190 or 195 or 200 megahertz.", "In this case, only one local oscillator or, respectively, voltage-controlled oscillator is capable of providing the requirements of the frequency duplex method with variable duplex frequency for a network operator which only has a limited bandwidth available.", "This makes it possible to have an FDD operation with variable duplex frequency with low power consumption and a low number of interference signals.", "In an advantageous embodiment of the present invention, a first changeover switch is provided by which it is possible to connect the first local oscillator or a further local oscillator to the second mixer.", "For an FDD operation with variable duplex frequency which only slightly deviates from the fixed duplex frequency, the power-saving operation with a single first local oscillator which is connected to the first mixer and to the second mixer is sufficient.", "If, however, it is intended to exploit the full spectrum of the FDD with variable frequency spacing from 134.8 to 245.2 megahertz, the second mixer can be switched to the further local oscillator.", "To prevent unwanted signals that are caused by the operation of two local oscillators which have closely adjacent frequencies of oscillation and by nonlinearities in the transceiver, the further local oscillator should have a frequency of oscillation which is below the transmitting frequency of the transceiver.", "As a result, the further local oscillator will not interfere with the first local oscillator as a result of which both local oscillators can be integrated in a common IC.", "In a further advantageous embodiment of the present invention, a baseband unit, to which the transmitting and receiving intermediate-frequency paths are connected, has a digital mixer which can be detuned in steps of 200 kilohertz.", "The digital mixer performs a frequency correction of +/−200 or, respectively, +/−400 kilohertz as deviation from the fixed duplex frequency of 190 megahertz.", "This two-step tuning solution has the advantage that the radio-frequency phase-locked loops can operate with steps of 1 megahertz in the first and further local oscillator.", "This reduces the multiplication of the phase noise in the phase-locked loops so that the requirements for phase detectors or charge pumps can be relaxed and the power consumption can thus be reduced.", "For example, the multiplication of the phase noise is reduced by a factor of 20* log (5) in the case of 1 megahertz steps in the phase detector.", "As a result, it will also be possible for the switchover of the phase-locked loop to be faster.", "The time for a frequency search in the UMTS system is reduced by a factor of 4 due to the fact that the switching times in the digital mixer are distinctly shorter in comparison with a phase-locked loop.", "The capacitances in the phase-locked loop can be smaller which results in additional advantages in the integration.", "Should 100 kilohertz frequency steps be needed in future due to changes in the UMTS specification, these can be implemented more easily in the digital mixer than in phase-locked loops.", "In accordance with an added feature of the invention, a third mixer is connected to the second mixer, a digital-to-analog converter is connected to the third mixer, and a third local oscillator is connected to the third mixer.", "In accordance with an additional feature of the invention, the first local oscillator, the second local oscillator and the third local oscillator in each case have a voltage-controlled oscillator and a phase-locked loop.", "In accordance with a further feature of the invention, the transceiver is a universal mobile telecommunications system transceiver, and the duplex unit has a frequency splitter and a switch connected to the frequency splitter.", "Other features which are considered as characteristic for the invention are set forth in the appended claims.", "Although the invention is illustrated and described herein as embodied in a transceiver, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.", "The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified block diagram of a transceiver according to the invention;", "and FIG. 2 is a block diagram of a second embodiment of the transceiver according to the invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case.", "Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a transceiver containing a duplex unit DE, which is connected to a transmitting and receiving antenna A. The duplex unit separates a transmitting branch T from a receiving branch R at this radio-frequency level.", "The receiving branch R exhibits a low-noise preamplifier LNA which is constructed to be controllable.", "The receiving branch R is connected to a first mixer M 1 that is connected to a first local oscillator LO 1 through a third switch SW 3 .", "In the first mixer M 1 , a received signal is down-converted to an intermediate-frequency level with a local-oscillator signal.", "The first mixer M 1 is connected to a receiving intermediate-frequency path RI that has an amplifier V 3 which is constructed to be controllable.", "The receiving intermediate-frequency path is followed by an analog/digital converter AD and a first digital mixer DM 1 .", "This is used for detuning the frequency in the receiving intermediate-frequency path RI in steps of 200 kilohertz.", "Other modules usually provided in a transceiver such as, for example, voice decoding are not drawn in FIG. 1 .", "The transmitting branch T exhibits a transmitting amplifier PA that is controllable and is connected to a second mixer M 2 .", "A transmitting intermediate-frequency path TI connected to the second mixer M 2 can exhibit an intermediate-frequency signal that is mixed with a local oscillator signal to form the desired transmitting frequency.", "The transmitting intermediate-frequency path TI exhibits a band-pass filter BP that has a mean frequency of 190 megahertz at an intermediate frequency of 190 megahertz in the transmitter.", "The pass band of the band-pass filter BP extends from 180 to 200 megahertz.", "A second local oscillator LO 2 is connected to a third mixer M 3 that is connected to the transmitting intermediate-frequency path TI.", "Furthermore, the third mixer M 3 is connected to a digital/analog converter chip DA, which is connected to a second digital mixer DM 2 for detuning the transmitting baseband frequency in 200 kilohertz steps.", "The third mixer M 3 is used for up-converting a baseband signal to an intermediate-frequency level by use of a second frequency of oscillation.", "The first and the second digital mixer DM 1 , DM 2 are also used for automatic frequency control (AFC) in the baseband.", "For this purpose, any frequency from 0.1 hertz up to half the clock frequency of the mixers can be set by the digital mixers.", "In the UMTS specification, a frequency pattern with steps of 200 kilohertz is described for transmitting and receiving.", "Together with synthesizers disposed in the local oscillators LO 1 , LO 1 ′, LO 2 and having a step length of 1 megahertz, any UMTS frequency can be advantageously set in a 200-kilohertz pattern by detuning the digital mixers by +/−200 kilohertz or by +/−400 kilohertz.", "For FDD operations with a variable duplex frequency which has a large deviation from the fixed duplex frequency of 190 megahertz, a first changeover switch SW 1 can be provided for switching the connection of the second mixer M 2 to the first local oscillator to another local oscillator LO 1 ′.", "Using the third switch SW 3 , the first mixer M 1 can be switched from the first local oscillator LO 1 ′ to the second local oscillator LO 2 .", "This is advantageous, in particular, for TDD reception since the frequencies of the first and of the further local oscillator LO 1 , LO 1 ′ differ distinctly from the required TDD receiving intermediate frequency in this case whereas the latter overlaps the frequency range of the second local oscillator when this corresponds to seven times the transmitting intermediate frequency and the doubled TDD receiving frequency can be generated by multiplying the frequency of the second local oscillator LO 2 by a factor of three.", "Since FDD or, respectively, TDD transmitting and TDD receiving do not take place simultaneously, the second local oscillator can support both operating modes.", "The first local oscillator LO 1 , the second local oscillator LO 2 and the further local oscillator LO 1 ′ are connected to a common reference oscillator XO.", "The configuration described has the advantage that the local oscillators have only a small tuning range.", "As a result, they are improved with respect to phase noise, sensitivity, substrate noise and response.", "Since, initially, full network coverage will not be guaranteed on introduction of the UMTS system and since, at the same time, the existing GSM networks offer almost all coverage, it is advantageous that UMTS transceivers are capable of monitoring the availability and the quality of the GSM channels in the case of poor UMTS reception.", "A special operating method, the so-called slotted mode, is provided for this purpose.", "This exhibits time gaps in the transmission during which the GSM channels can be monitored.", "To keep the transmission rate constant, the data must be compressed preceding the gaps.", "The so-called compressed mode is provided for this purpose.", "However, this reduces the network capacity.", "The slotted mode is provided for monitoring GSM 1800 channels whereas GSM 900 channels, that is to say GSM reception, can be simultaneously monitored with UMTS transmission.", "The first and the second local oscillators LO 1 , LO 2 are used for this UMTS transmission while at the same time the further local oscillator LO 1 ′ is used for GSM reception.", "For this purpose, a fourth switch SW 4 is provided which can switch the further local oscillator LO 1 ′ through to a GSM transceiver.", "For better clarity, a table containing the frequency ranges of the local oscillators in megahertz (third and fourth row) and the respective transmitting and receiving modes (first column) is specified.", "An X here indicates an active local oscillator.", "Tx stands for transmit and Rx for receive.", "Local oscillator LO1 LO2 LO1′ Operating mode TDD GSM GSM Rx 900 Rx 1800 Rx Frequency range in MHz 4184 1330 3800 3464 3700 3610 to +/−70 to to to to 4426 4050 3840 3840 3760 FDD Fixed duplex Tx X X FDD Fixed duplex Rx X FDD Var.", "duplex +/−5, +/−10 MHz Tx X X FDD Var.", "duplex +/−5, +/−10 MHz Rx X FDD Var.", "duplex 134.8-245.2 MHz Tx X X FDD Var.", "duplex 134.8-245.2 MHz Rx X TDD Tx X X TDD Rx X FDD standby Rx X TDD standby Rx X UMTS FDD transmit Tx X X GSM receive Rx X UMTS TDD transmit Tx X X GSM receive Rx X The frequency range of the second local oscillator LO 2 in FDD mode from 1260 to 1400 megahertz corresponds to seven times the transmitting intermediate frequency which is in a range from 180 megahertz to 200 megahertz.", "The frequency range of the second local oscillator LO 2 for the TDD operating mode is in the range of the third harmonic of the frequency range of the second local oscillator LO 2 in FDD mode.", "For GSM 900, that is to say a GSM system in the 900 megahertz band, a local oscillator frequency of from 3700 to 3840 megahertz is required with a receiving band from 925 to 960 megahertz and four times the frequency.", "For GSM 1800, that is to say a GSM system in the 1800 megahertz band, a local oscillator frequency of from 3610 to 3760 megahertz is required with a receiving band from 1805 to 1880 megahertz and twice the frequency.", "The exemplary embodiment according to FIG. 1 has the advantage that operation is possible both with time division duplex, frequency division duplex with fixed duplex frequency and frequency division duplex with variable duplex frequency.", "The simple structure and the high integration capability are the result of the receiving intermediate frequency in a range from 0 to 0.5 megahertz and the transmitting intermediate frequency of 190 megahertz.", "The lower transmitting and receiving intermediate frequencies compared with known IMT 2000 transceivers and the possible operation using only one first local oscillator LO 1 ensure low power consumption.", "FIG. 2 shows a second exemplary embodiment containing the duplex unit DE which has a frequency splitter DUP and a switch SW 2 .", "The frequency splitter DUP separates the FDD downlink band that is supplied to a first low-noise preamplifier LNA 1 from FDD uplink and TDD bands by a suitable choice of transmitting and receiving filters.", "Transmission and reception in TDD mode are separated in the second switch SW 2 .", "The second low-noise preamplifier LNA 2 is used for amplifying in TDD receiving mode.", "The band-pass filters BP 1 , BP 2 following the low-noise preamplifiers LNA 1 , LNA 2 are adapted to the respective receiving frequency bands and to the amplifiers V 1 , V 2 following them.", "To convert the receiving frequencies into an intermediate frequency of 0 megahertz, two first mixers M 1 , M 1 ′ are provided, which are in each case followed by a low-pass filter TP 1 , TP 1 ′.", "The first mixers M 1 , M 1 ′ are supplied with a halved first local oscillator frequency LO 1 which is generated in a first local oscillator LO 1 and amplified in an amplifier V 6 .", "The intermediate-frequency signals are supplied to an A/D converter AD, AD′ from additional amplifiers V 3 , V 3 ′ followed by low-pass filters TP 2 , TP 2 ′ in which a DC offset compensation is performed by a compensator DC.", "AC coupling is possible as an alternative to this DC offset compensation.", "At the transmitting end T, a directional filter FI preceded by a controllable power amplifier PA and a band-pass filter BP 5 is connected to the duplex unit DE.", "These are preceded by a gain-controlled amplifier AGC 2 .", "A second mixer M 2 which up-converts the transmitting intermediate frequency to the respective desired transmitting frequency by using a local oscillator frequency is connected via a further band-pass filter BP 4 .", "The first switch SW 1 can switch the frequency of oscillation to be supplied to the second mixer M 2 via a divider V 5 which divides by two, between the first local oscillator LO 1 and the further local oscillator LO 1 ′.", "The second mixer M 2 is preceded by third mixers M 3 , M 3 ′ which up-convert signals conditioned in digital/analog converters DA, DA′ and low-pass filters TP 3 , TP 3 ′ to the transmitting intermediate frequency by the second local oscillator LO 2 .", "An amplifier V 4 , a band-pass filter BP 3 and a gain-controlled amplifier AGC 1 are provided between the second and third mixer M 2 , M 3 in the transmitting intermediate-frequency path TI.", "The local oscillators LO 1 , LO 1 ′, LO 2 in each case have a phase-locked loop PLL 1 , PLL 1 ′, PLL 2 and a voltage-controlled oscillator VCO 1 , VCO 1 ′, VCO 2 .", "The circuit configuration of the transceiver according to FIG. 2 provides for operation with frequency division duplex with a fixed duplex frequency, frequency division duplex with a variable duplex frequency and time division duplex.", "If a narrow bandwidth of, for example, 15 megahertz is available to a network operator in the UMTS system, an energy-saving FDD mode with variable duplex frequency using only one first local oscillator LO 1 which is connected to first and second mixers M 1 , M 2 can be effected with the present transceiver.", "The circuit configuration described provides for a high-density integration." ]
CROSS REFERENCE TO RELATED APPLICATION The present application is based on and claims priority from Japanese Patent Applications: Hei 10-191743, filed on Jul. 7, 1998 and Hei 10-214977, filed on Jul. 30, 1998, the contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a center piece structure of a brush-less motor and a method of manufacturing the brush-less motor. 2. Description of the Related Art A common outer rotor type brush-less motor has a stator core fixed to an upper surface of a motor holder and a stator winding supported by a center piece which has a flange portion and a cylindrical portion. The cylindrical portion has an inner periphery which supports a pair of bearings, which rotatably supports a rotor shaft. Usually, such a center piece has been made of aluminum alloy die-cast. However, such a center piece may need another machining step for finishing to provide necessary precision and bearing's retaining surfaces. This increases production cost and time. SUMMARY OF THE INVENTION A main object of the invention is to provide a brush-less motor having an improved center piece structure. According to a preferred embodiment of the invention, a brush-less motor includes a press-formed center piece which does not require additional finishing step. The cylindrical portion may have a cut-down projection extending radially inward to position bearing members in the axial direction thereof. According to another preferred embodiment of the invention, a method of manufacturing a brush-less motor including a step of providing a stator winding on the stator core, and a step of fixing an outer periphery of the cylindrical portion to the stator core thereafter. BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and characteristics of the present invention as well as the functions of related parts of the present invention will become clear from a study of the following detailed description, the appended claims and the drawings. In the drawings: FIG. 1 is a cross-sectional view illustrating a brush-less motor according to a preferred embodiment of the invention; FIG. 2 is an exploded view illustrating a main portion of the brush-less motor illustrated in FIG. 1; and FIG. 3 is a center piece of the brush-less motor illustrated in FIG. 1 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, stator 2 is fixed to upper surface 1 a of motor holder 1 . Stator 2 has center piece 3 , stator core 4 and stator winding 5 . Stator core 4 has a central opening 4 a, a plurality of teeth extending radially outward, and slots formed therebetween. Stator winding 5 is wound around the teeth in a well-known manner, however, before stator core 4 is fixed to center piece 3 , because sufficient space for a winding tool can be provided. This can provide stator 2 with any one of various types of stator windings easily. As shown in FIG. 3, center piece 3 is press-formed from a metal plate such as iron alloy or steel to have semi-annular flange 3 a and cylindrical portion 3 b extending from a central portion of flange 3 a. Three projections 3 c project downward from the lower peripheral surface of flange 3 a. Each projection 3 c has a through screw hole 3 d therein. Three openings 3 e are also formed in flange 3 a near cylindrical portion 3 b, through which lead wires of stator winding 5 pass to be connected to printed circuit board 11 . Flange 3 a has straight edge 3 f and a circular edge having concavity 3 g. Cylindrical portion 3 b has end portion 3 h of a reduced outside diameter and inner periphery 3 i. Four upper cut-down projections 3 j and four lower cut-down projections 3 k are respectively formed at the axially middle of cylindrical portion 3 b at equal intervals to project radially inward therefrom. Cut-down projections 3 j, 3 k provide retaining surfaces 3 m, 3 n. Because center piece 3 is press-formed, cylindrical portion 3 b can be inserted into center hole 4 a of stator core 4 , as shown in FIG. 2, without additional machine-finishing step. Upper bearing 6 a has a bearing portion which supports rotor shaft 10 and an axially extending portion 6 c. Axially extending portion 6 c has an outer periphery press-fitted into inner periphery 3 i of cylindrical portion 3 b from the upper end thereof and an inner periphery whose diameter is much larger than the diameter of the rotor shaft 10 . Lower bearing 6 b has a bearing portion which supports rotor shaft 10 and an axially extending portion 6 d. Axially extending portion 6 d has an outer periphery press-fitted into inner periphery 3 i from the lower end thereof and an inner periphery whose diameter is much larger than the diameter of the rotor shaft 10 . Each of the bearing portions of bearings 6 a, 6 b has outer periphery whose diameter is smaller than the diameter of axially extending portions 6 c, 6 d. Although the outer periphery of extending portions 6 c, 6 d may shrink when bearings 6 a, 6 b are press-fitted into the inner periphery 3 i of cylindrical portion 3 b, the bearing portions do not shrink. As a result, both bearings 6 a and 6 b are respectively retained and positioned in the axial direction by retaining surfaces 3 m, 3 n so that inner bearing surfaces 6 e, 6 f of bearings 6 a, 6 b correctly support rotor shaft 10 . Rotor shaft 10 is then press-fitted into bearing surfaces 6 e, 6 f, so that rotor 7 can be rotatably supported by stator 2 via center piece 3 . Bell-shaped yoke 8 , which has a center boss and a plurality of permanent magnets 9 fixed to the inner periphery thereof, is also press-fitted to rotor shaft 10 at the center boss to rotate therewith. Yoke 8 surrounds stator 2 so that permanent magnets 9 can face stator core 4 . Printed circuit board 11 , which has a field exciting circuit therein, is fixed to the lower surface of motor holder 1 . When stator winding 5 is energized by the exciting circuit, stator 2 provides a rotating magnetic field to rotate rotor 7 . In the foregoing description of the present invention, the invention has been disclosed with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made to the specific embodiments of the present invention without departing from the broader spirit and scope of the invention as set forth in the appended claims. Accordingly, the description of the present invention in this document is to be regarded in an illustrative, rather than restrictive, sense.
A brush-less motor has a center piece, which has a flange portion fixed to a motor holder and a cylindrical portion fixed to a stator core at the outer periphery of the cylindrical portion. The cylindrical portion has a pair of bearings disposed inside the cylindrical portion to rotatably support said shaft. The center piece is formed by a pressing machine to omit a finishing machine work.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "CROSS REFERENCE TO RELATED APPLICATION The present application is based on and claims priority from Japanese Patent Applications: Hei 10-191743, filed on Jul. 7, 1998 and Hei 10-214977, filed on Jul. 30, 1998, the contents of which are incorporated herein by reference.", "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to a center piece structure of a brush-less motor and a method of manufacturing the brush-less motor.", "Description of the Related Art A common outer rotor type brush-less motor has a stator core fixed to an upper surface of a motor holder and a stator winding supported by a center piece which has a flange portion and a cylindrical portion.", "The cylindrical portion has an inner periphery which supports a pair of bearings, which rotatably supports a rotor shaft.", "Usually, such a center piece has been made of aluminum alloy die-cast.", "However, such a center piece may need another machining step for finishing to provide necessary precision and bearing's retaining surfaces.", "This increases production cost and time.", "SUMMARY OF THE INVENTION A main object of the invention is to provide a brush-less motor having an improved center piece structure.", "According to a preferred embodiment of the invention, a brush-less motor includes a press-formed center piece which does not require additional finishing step.", "The cylindrical portion may have a cut-down projection extending radially inward to position bearing members in the axial direction thereof.", "According to another preferred embodiment of the invention, a method of manufacturing a brush-less motor including a step of providing a stator winding on the stator core, and a step of fixing an outer periphery of the cylindrical portion to the stator core thereafter.", "BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and characteristics of the present invention as well as the functions of related parts of the present invention will become clear from a study of the following detailed description, the appended claims and the drawings.", "In the drawings: FIG. 1 is a cross-sectional view illustrating a brush-less motor according to a preferred embodiment of the invention;", "FIG. 2 is an exploded view illustrating a main portion of the brush-less motor illustrated in FIG. 1;", "and FIG. 3 is a center piece of the brush-less motor illustrated in FIG. 1 .", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, stator 2 is fixed to upper surface 1 a of motor holder 1 .", "Stator 2 has center piece 3 , stator core 4 and stator winding 5 .", "Stator core 4 has a central opening 4 a, a plurality of teeth extending radially outward, and slots formed therebetween.", "Stator winding 5 is wound around the teeth in a well-known manner, however, before stator core 4 is fixed to center piece 3 , because sufficient space for a winding tool can be provided.", "This can provide stator 2 with any one of various types of stator windings easily.", "As shown in FIG. 3, center piece 3 is press-formed from a metal plate such as iron alloy or steel to have semi-annular flange 3 a and cylindrical portion 3 b extending from a central portion of flange 3 a. Three projections 3 c project downward from the lower peripheral surface of flange 3 a. Each projection 3 c has a through screw hole 3 d therein.", "Three openings 3 e are also formed in flange 3 a near cylindrical portion 3 b, through which lead wires of stator winding 5 pass to be connected to printed circuit board 11 .", "Flange 3 a has straight edge 3 f and a circular edge having concavity 3 g. Cylindrical portion 3 b has end portion 3 h of a reduced outside diameter and inner periphery 3 i. Four upper cut-down projections 3 j and four lower cut-down projections 3 k are respectively formed at the axially middle of cylindrical portion 3 b at equal intervals to project radially inward therefrom.", "Cut-down projections 3 j, 3 k provide retaining surfaces 3 m, 3 n. Because center piece 3 is press-formed, cylindrical portion 3 b can be inserted into center hole 4 a of stator core 4 , as shown in FIG. 2, without additional machine-finishing step.", "Upper bearing 6 a has a bearing portion which supports rotor shaft 10 and an axially extending portion 6 c. Axially extending portion 6 c has an outer periphery press-fitted into inner periphery 3 i of cylindrical portion 3 b from the upper end thereof and an inner periphery whose diameter is much larger than the diameter of the rotor shaft 10 .", "Lower bearing 6 b has a bearing portion which supports rotor shaft 10 and an axially extending portion 6 d. Axially extending portion 6 d has an outer periphery press-fitted into inner periphery 3 i from the lower end thereof and an inner periphery whose diameter is much larger than the diameter of the rotor shaft 10 .", "Each of the bearing portions of bearings 6 a, 6 b has outer periphery whose diameter is smaller than the diameter of axially extending portions 6 c, 6 d. Although the outer periphery of extending portions 6 c, 6 d may shrink when bearings 6 a, 6 b are press-fitted into the inner periphery 3 i of cylindrical portion 3 b, the bearing portions do not shrink.", "As a result, both bearings 6 a and 6 b are respectively retained and positioned in the axial direction by retaining surfaces 3 m, 3 n so that inner bearing surfaces 6 e, 6 f of bearings 6 a, 6 b correctly support rotor shaft 10 .", "Rotor shaft 10 is then press-fitted into bearing surfaces 6 e, 6 f, so that rotor 7 can be rotatably supported by stator 2 via center piece 3 .", "Bell-shaped yoke 8 , which has a center boss and a plurality of permanent magnets 9 fixed to the inner periphery thereof, is also press-fitted to rotor shaft 10 at the center boss to rotate therewith.", "Yoke 8 surrounds stator 2 so that permanent magnets 9 can face stator core 4 .", "Printed circuit board 11 , which has a field exciting circuit therein, is fixed to the lower surface of motor holder 1 .", "When stator winding 5 is energized by the exciting circuit, stator 2 provides a rotating magnetic field to rotate rotor 7 .", "In the foregoing description of the present invention, the invention has been disclosed with reference to specific embodiments thereof.", "It will, however, be evident that various modifications and changes may be made to the specific embodiments of the present invention without departing from the broader spirit and scope of the invention as set forth in the appended claims.", "Accordingly, the description of the present invention in this document is to be regarded in an illustrative, rather than restrictive, sense." ]
FIELD OF THE INVENTION This invention relates to superconducting rotating devices and, more particularly, to superconducting bearings which employ Type II superconductors. The U.S. Government has a non-exclusive license right to this invention as a result of partial support thereof by a grant from the National Science Foundation. BACKGROUND OF THE INVENTION Conventional bearings for high speed rotating devices are know to be subject to wear, noise, vibration and thermal problems. Until recently, practical magnetic bearings have been of either the permanent magnet or the electromagnet feedback type. Permanent magnet bearings are subject to inherent static instabilities and must be stabilized in at least one degree of freedom by non-magnetic means (e.g. a rotatable coupling). Feedback--based magnetic bearings often require elaborate position sensors and electronics to achieve stability. The prior art has attempted to improve the magnetic bearing art by turning to superconductivity. In such instances, either the bearing member or the rotating member or both are maintained in a Type I superconducting state so as to achieve a magnetic pressure therebetween and thereby provide a desired degree of levitation. Type I superconductors exhibit perfect diamagnetism up to a critical applied field, at which point superconductivity is lost and the magnetization of the sample rises abruptly. Examples of superconducting bearings of the Type I kind can be found in U.S. Pat. Nos. 3,493,274 to Emslie et al and 3,026,151 to Buchhold. In order to obtain stability in those systems, the bearing structures generally rely on either a mechanical rotary support (e.g. Buchhold) or employ dished or other encompassing type superconductors whereby the shape provides a gravitational minimum which leads to limited lateral stability (see Emslie et al). Recently, others have discovered new ceramic compositions which exhibit superconducting properties at temperatures in excess of liquid nitrogen. These new superconductors are generally Type II materials with upper critical fields typically greater than 30-35 Teslas. A Type I superconductor may be said to "screen out" magnetic flux from its interior. By contrast, a Type II superconductor enables magnetic flux to penetrate into its interior in clusters of flux lines. Under such circumstances, circulating superconducting currents are established within the Type II superconductor. They, in turn, generate substantial magnetic fields and exert a positional pinning effect on a magnet levitated over the surface of the superconductor. A benefit to be potentially gained from a levitated superconducting bearing is its ability to achieve rotational speeds of 10's of thousands of rpm. In order to attain such speeds, teachings of the prior art which suggest immersion of the entire unit in a liquid helium/nitrogen environment are impractical. Prior art teachings that call for exquisitely balanced rotors with "hard suspensions" are also to be avoided if possible. Furthermore, external rotational stabilization is to be avoided, if at all possible. Accordingly, it is an object of this invention to provide a superconducting rotating assembly which exhibits levitated lateral, vertical and axial stability while enabling rotation at high speed. It is another object of this invention to provide a superconducting rotating assembly of simple and inexpensive design which is adapted for high speed, stable rotation. It is a further object of this invention to provide a superconducting rotating assembly which employs a soft suspension for accommodating rotors with significant imbalance. SUMMARY OF THE INVENTION In accordance with the above objects, a non-contacting, soft suspension, superconducting rotating assembly is disclosed which includes a floating, unsupported and stable rotatable member. The assembly includes first and second opposed, suitably shaped bearing means comprised of a material which exhibits Type II superconducting properties. The rotatable member includes magnet means at each extremity which rest in the opposed bearing means. The axis connecting the north and south poles of each such magnet means is colinear with the rotating axis of the rotatable member. Means are provided for maintaining the bearing means at or below the critical superconducting temperature and means are additionally provided for rotating the rotatable member. Each magnet means is thereby levitated and adapted to rotate in a stable, non-contacting position by the field and pinning effects generated by the associated bearing means. DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the invention. FIG. 2 is a section view of the invention taken along the line 2--2 shown in FIG. 1. FIG. 3 is an enlarged isometric of the Type II superconducting bearing shown in FIG. 1. FIG. 4 is a plot of the variations in repulsive force with thickness for a Type II superconducting bearing. FIG. 5 illustrates a two coil drive for the superconducting rotating assembly. FIG. 6 illustrates a three coil drive for the superconducting rotating assembly. FIG. 7 illustrates a four coil drive for the superconducting rotating assembly. FIGS. 8(a), 8(b) and 8(c) illustrate a first alternative bearing configuration for the invention. FIGS. 9(a) and 9(b) illustrate second and third alternative bearing configurations for the invention. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, a rotor 10 fits within recesses 12 and 14 in bearing blocks 16 and 18 respectively. Each of bearing blocks 16 and 18 is mounted on a copper or aluminum pedestal 20 which is, in turn, immersed in a supercold liquid such as liquid nitrogen. Four coils (of which one is not shown) 22, 24 and 26, provide the motive force to cause rotation of rotor 10. Each of bearing blocks 16 and 18 is comprised of a material which exhibits Type II superconducting properties when it is maintained at a temperature less than its critical temperature. A preferred material for bearing blocks 16 and 18 is the ceramic compound YBa 2 Cu 3 O x . Other Thallium, Bismuth or other ceramic based compounds which exhibit Type II superconducting properties are also acceptable. An appropriate material for pedestals 20 is a 60/63 alloy of aluminum. Referring now to FIG. 2, rotor 10 is shown in section and includes two levitating magnets 30 and 32 which are preferably cylindrical in shape and have their north/south polar axes aligned with centerline 34 of rotor 10. A third magnet 36 has its polar axis oriented orthogonally to centerline 34 and generates a field to enable rotor 10 to be rotated by field coils 22, 24 and 26 etc. Magnets 30 and 32 are mounted in and maintained in position by hollow cylinders 40 and 42 in combination with elongated cylinder 44. Cylinders 40, 42 and 44 may be comprised of any suitable non-magnetic material which provides sufficient stiffness to enable rotor 10 to maintain dimensional stability as it rotates at high speed. Polycarbonates and other similar polymeric materials are suitable. Magnets 30 and 32 are preferably comprised of samarium cobalt and exhibit a linear dipole as shown in FIG. 2. Other rare earth magnets are also acceptable (for instance Nd, B, Fe based magnets). Magnet 36 may also be comprised of a similar rare earth material or of some other suitable permanent magnet material. While it is desirable to make rotor 10 as balanced as possible about its centerline, no special balancing is required for high speed operation, due in the main to the "soft suspension" created by bearing blocks 16 and 18. In other words, some "wobble" is accommodated by the suspension without detriment to the system. Referring now to FIGS. 2 and 3 in conjunction, and further assuming that the assembly shown in FIG. 2 is at a superconducting temperature, the placement of rotor 10 in bearing recesses 12 and 14 causes induced supercurrents in the wall areas of the bearing recesses. It should be noted that the bearing recesses 12 and 14 do not totally enclose the circumference of the respective ends of the rotor 10. The supercurrents are shown by arrows 50 and create electromagnetic repulsion forces illustrated by arrows 52. Those forces act to elevate and pin magnets 30 and 32 to a stable levitated position. The horizontal, side and end walls of each bearing recess, in combination, enable the electromagnetic pinning forces to exert a stabilizing effect on its associated rotor magnet. Importantly, the internal surfaces of each bearing recess see no change in the polarity of flux as rotation of rotor 10 occurs. This is important as it avoids the imposition of displacement torques on the rotating magnets which would tend to cause rotor 10 to become unstable. In other words, if, during rotation, recess 12 experienced subsequent north and south poles during the rotation of rotor 10, the resulting torques exerted by the interfering fields would prevent the system from obtaining the desired high rotational speeds. As can be seen from an examination of FIG. 4, the repulsive force exerted by Type II superconducting materials has been found to be a mass-related phenomenon. Thus, as the thickness of superconductor adjacent to each bearing recess is increased, so also does the repulsion force it exerts on a magnet which is bought into proximity. However, it can be seen from the curve that at approximately 5 mm or greater thickness, there is no further substantial increase in the repulsive force. Thus, it is preferable that the thickness (t) surrounding the bearing recesses be at least 5 mm so as to assure the maximum repulsive force on rotor 10. This enables the mass of rotor 10 to be maximized. While not shown in the drawings, in normal use, rotor 10 may have mounted thereon any number of different types of components. For example, it may have mounted thereon a multifaceted mirror which may be used in conjunction with a laser beam to scan an appropriate target; it may further have mounted thereon a small disk particularly adapted to optical data storage etc. The provision of conductive pedestals 20 to support bearing blocks 16 and 18 enables the level of the superconducting fluid to be kept substantially away from the rotating member. Thus, the rotating member and upper portions of bearing blocks 16 and 18 may be mounted in a vacuum to enable ultra-high rotating speeds. It has been found that bearings blocks 16 and 18 will obtain Type II superconducting properties when pedestals 20 are immersed in liquid nitrogen, even when such immersion occurs at a substantial distance from the bearing blocks. Referring now to FIGS. 5-7, shown therein are schematic diagrams of systems for imparting rotational motion to rotor 10. In FIG. 5, a two coil system is shown wherein magnet 36 is caused to rotate by the imposition of an ac current in the two coils, with the phase in one coil being related to the other by a cosine function. In FIG. 6, a three coil drive system is shown wherein the coils are placed at 120° intervals and are driven 120° out of phase with each other. In FIG. 7, a four coil drive is shown with each coil being driven 90° out of phase with the other to create a rotating field which again imparts rotational movement to rotor 10. While each of the above rotational systems involves the use of electromagnetic energy, rotor 10 could also be rotated through the use of a high pressure gas jet pointed at a circumferential portion of rotor 10 which has been serrated or has emplaced thereon, turbine blades. Referring now to FIGS. 8(a), 8(b) and 8(c), a circular Type II superconducting bearing structure 72 is illustrated which includes an orifice 73 enclosing each extremity of rotor 10. As with the system shown in FIG. 1, rotor 10 includes magnets 70 at each of its extremities. In this configuration, the rotor/bearing assembly can be operated in any orientation with respect to gravity (e.g. see FIG. 8(c)). In FIGS. 9(a) and 9(b), further alternative bearing embodiments are shown. In FIG. 9(a), magnets 70 have been replaced by ring magnets which encircles a pedestal 82 emanating from the center of bearing block 80. In FIG. 9(b), each of magnets 70 is replaced by a magnet with a concave indentation which mates with a conical pedestal emanating from bearing block 80. EXAMPLE Several pairs of YBa 2 Cu 3 O x bearing blocks, 1.5 cm in diameter were made by a sintering process at 950° C. in air. The crystals were randomly oriented and the specimen required a post anneal treatment in pressurized oxygen (20 bars) at 800° C. for 2 hours in order to obtain a Tc greater than 90° Kelvin. Some of the bearing blocks were shaped as shown in FIGS. 1-3. Using a Hall effect probe, normal flux density measurements could be made on the surface of the superconductor underneath a levitated permanent magnet. When the permanent magnet dipole was parallel to the ceramic bearing surface, normal flux surface measurements were of the order of 0.07 Tesla. The sign of the normal flow indicated that two superconducting eddy current vortices were active in the superconductor, one near each of the two magnets' poles. The surface field measurement also indicated that incomplete flux exclusion was in effect during levitation which is typical of Type II superconductors. There was considerable hysteretic behavior in the levitation level of the rotor. For small perturbation forces, the levitated rotor exhibited lateral and vertical stiffness. The rotor was spun by a magnetic field created by nearby coils. No discernible effect by the alternating field on the superconductor or the levitation height was observed with and without rotation. At low frequencies, however (1-4 Hz), periodic magnetic forces excited the magnetic stiffness modes through a resonance which sometimes evicted the rotor off the superconducting bearing pads. At higher frequencies, lock-in of the rotor speed and driving field frequency occurred and permitted increase of the rotor speed to over 12,000 rpm. The low frequency instability was readily overcome by rapidly moving the rotor through the resonant frequencies by substantial application of the energizing field. It is surmised that flux pinning creates the hysteretic effects of the magnetic forces on the rotor. Nevertheless, the rotor once in position maintains a stable position, unless pushed out of it by an external force. It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.
A non-contacting superconducting rotating assembly is described which includes a floating, unsupported and stable rotor. The assembly includes first and second bearings comprised of a material which exhibits Type II superconducting properties. The rotor includes a magnetic pole at each of its extremities, each pole resting in a bearing. The polar axis of each pole is colinear with the rotating axis of the rotor. A temperature bath is provided for maintaining the bearings at or below their critical superconducting temperature and a motive mechanism provides for rotation of the rotor. Each magnet pole is thereby levitated and adapted to rotate in a stable, non-contacting position by the field and pinning effects generated by the associated bearing.
Concisely explain the essential features and purpose of the invention.
[ "FIELD OF THE INVENTION This invention relates to superconducting rotating devices and, more particularly, to superconducting bearings which employ Type II superconductors.", "The U.S. Government has a non-exclusive license right to this invention as a result of partial support thereof by a grant from the National Science Foundation.", "BACKGROUND OF THE INVENTION Conventional bearings for high speed rotating devices are know to be subject to wear, noise, vibration and thermal problems.", "Until recently, practical magnetic bearings have been of either the permanent magnet or the electromagnet feedback type.", "Permanent magnet bearings are subject to inherent static instabilities and must be stabilized in at least one degree of freedom by non-magnetic means (e.g. a rotatable coupling).", "Feedback--based magnetic bearings often require elaborate position sensors and electronics to achieve stability.", "The prior art has attempted to improve the magnetic bearing art by turning to superconductivity.", "In such instances, either the bearing member or the rotating member or both are maintained in a Type I superconducting state so as to achieve a magnetic pressure therebetween and thereby provide a desired degree of levitation.", "Type I superconductors exhibit perfect diamagnetism up to a critical applied field, at which point superconductivity is lost and the magnetization of the sample rises abruptly.", "Examples of superconducting bearings of the Type I kind can be found in U.S. Pat. Nos. 3,493,274 to Emslie et al and 3,026,151 to Buchhold.", "In order to obtain stability in those systems, the bearing structures generally rely on either a mechanical rotary support (e.g. Buchhold) or employ dished or other encompassing type superconductors whereby the shape provides a gravitational minimum which leads to limited lateral stability (see Emslie et al).", "Recently, others have discovered new ceramic compositions which exhibit superconducting properties at temperatures in excess of liquid nitrogen.", "These new superconductors are generally Type II materials with upper critical fields typically greater than 30-35 Teslas.", "A Type I superconductor may be said to "screen out"", "magnetic flux from its interior.", "By contrast, a Type II superconductor enables magnetic flux to penetrate into its interior in clusters of flux lines.", "Under such circumstances, circulating superconducting currents are established within the Type II superconductor.", "They, in turn, generate substantial magnetic fields and exert a positional pinning effect on a magnet levitated over the surface of the superconductor.", "A benefit to be potentially gained from a levitated superconducting bearing is its ability to achieve rotational speeds of 10's of thousands of rpm.", "In order to attain such speeds, teachings of the prior art which suggest immersion of the entire unit in a liquid helium/nitrogen environment are impractical.", "Prior art teachings that call for exquisitely balanced rotors with "hard suspensions"", "are also to be avoided if possible.", "Furthermore, external rotational stabilization is to be avoided, if at all possible.", "Accordingly, it is an object of this invention to provide a superconducting rotating assembly which exhibits levitated lateral, vertical and axial stability while enabling rotation at high speed.", "It is another object of this invention to provide a superconducting rotating assembly of simple and inexpensive design which is adapted for high speed, stable rotation.", "It is a further object of this invention to provide a superconducting rotating assembly which employs a soft suspension for accommodating rotors with significant imbalance.", "SUMMARY OF THE INVENTION In accordance with the above objects, a non-contacting, soft suspension, superconducting rotating assembly is disclosed which includes a floating, unsupported and stable rotatable member.", "The assembly includes first and second opposed, suitably shaped bearing means comprised of a material which exhibits Type II superconducting properties.", "The rotatable member includes magnet means at each extremity which rest in the opposed bearing means.", "The axis connecting the north and south poles of each such magnet means is colinear with the rotating axis of the rotatable member.", "Means are provided for maintaining the bearing means at or below the critical superconducting temperature and means are additionally provided for rotating the rotatable member.", "Each magnet means is thereby levitated and adapted to rotate in a stable, non-contacting position by the field and pinning effects generated by the associated bearing means.", "DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the invention.", "FIG. 2 is a section view of the invention taken along the line 2--2 shown in FIG. 1. FIG. 3 is an enlarged isometric of the Type II superconducting bearing shown in FIG. 1. FIG. 4 is a plot of the variations in repulsive force with thickness for a Type II superconducting bearing.", "FIG. 5 illustrates a two coil drive for the superconducting rotating assembly.", "FIG. 6 illustrates a three coil drive for the superconducting rotating assembly.", "FIG. 7 illustrates a four coil drive for the superconducting rotating assembly.", "FIGS. 8(a), 8(b) and 8(c) illustrate a first alternative bearing configuration for the invention.", "FIGS. 9(a) and 9(b) illustrate second and third alternative bearing configurations for the invention.", "DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, a rotor 10 fits within recesses 12 and 14 in bearing blocks 16 and 18 respectively.", "Each of bearing blocks 16 and 18 is mounted on a copper or aluminum pedestal 20 which is, in turn, immersed in a supercold liquid such as liquid nitrogen.", "Four coils (of which one is not shown) 22, 24 and 26, provide the motive force to cause rotation of rotor 10.", "Each of bearing blocks 16 and 18 is comprised of a material which exhibits Type II superconducting properties when it is maintained at a temperature less than its critical temperature.", "A preferred material for bearing blocks 16 and 18 is the ceramic compound YBa 2 Cu 3 O x .", "Other Thallium, Bismuth or other ceramic based compounds which exhibit Type II superconducting properties are also acceptable.", "An appropriate material for pedestals 20 is a 60/63 alloy of aluminum.", "Referring now to FIG. 2, rotor 10 is shown in section and includes two levitating magnets 30 and 32 which are preferably cylindrical in shape and have their north/south polar axes aligned with centerline 34 of rotor 10.", "A third magnet 36 has its polar axis oriented orthogonally to centerline 34 and generates a field to enable rotor 10 to be rotated by field coils 22, 24 and 26 etc.", "Magnets 30 and 32 are mounted in and maintained in position by hollow cylinders 40 and 42 in combination with elongated cylinder 44.", "Cylinders 40, 42 and 44 may be comprised of any suitable non-magnetic material which provides sufficient stiffness to enable rotor 10 to maintain dimensional stability as it rotates at high speed.", "Polycarbonates and other similar polymeric materials are suitable.", "Magnets 30 and 32 are preferably comprised of samarium cobalt and exhibit a linear dipole as shown in FIG. 2. Other rare earth magnets are also acceptable (for instance Nd, B, Fe based magnets).", "Magnet 36 may also be comprised of a similar rare earth material or of some other suitable permanent magnet material.", "While it is desirable to make rotor 10 as balanced as possible about its centerline, no special balancing is required for high speed operation, due in the main to the "soft suspension"", "created by bearing blocks 16 and 18.", "In other words, some "wobble"", "is accommodated by the suspension without detriment to the system.", "Referring now to FIGS. 2 and 3 in conjunction, and further assuming that the assembly shown in FIG. 2 is at a superconducting temperature, the placement of rotor 10 in bearing recesses 12 and 14 causes induced supercurrents in the wall areas of the bearing recesses.", "It should be noted that the bearing recesses 12 and 14 do not totally enclose the circumference of the respective ends of the rotor 10.", "The supercurrents are shown by arrows 50 and create electromagnetic repulsion forces illustrated by arrows 52.", "Those forces act to elevate and pin magnets 30 and 32 to a stable levitated position.", "The horizontal, side and end walls of each bearing recess, in combination, enable the electromagnetic pinning forces to exert a stabilizing effect on its associated rotor magnet.", "Importantly, the internal surfaces of each bearing recess see no change in the polarity of flux as rotation of rotor 10 occurs.", "This is important as it avoids the imposition of displacement torques on the rotating magnets which would tend to cause rotor 10 to become unstable.", "In other words, if, during rotation, recess 12 experienced subsequent north and south poles during the rotation of rotor 10, the resulting torques exerted by the interfering fields would prevent the system from obtaining the desired high rotational speeds.", "As can be seen from an examination of FIG. 4, the repulsive force exerted by Type II superconducting materials has been found to be a mass-related phenomenon.", "Thus, as the thickness of superconductor adjacent to each bearing recess is increased, so also does the repulsion force it exerts on a magnet which is bought into proximity.", "However, it can be seen from the curve that at approximately 5 mm or greater thickness, there is no further substantial increase in the repulsive force.", "Thus, it is preferable that the thickness (t) surrounding the bearing recesses be at least 5 mm so as to assure the maximum repulsive force on rotor 10.", "This enables the mass of rotor 10 to be maximized.", "While not shown in the drawings, in normal use, rotor 10 may have mounted thereon any number of different types of components.", "For example, it may have mounted thereon a multifaceted mirror which may be used in conjunction with a laser beam to scan an appropriate target;", "it may further have mounted thereon a small disk particularly adapted to optical data storage etc.", "The provision of conductive pedestals 20 to support bearing blocks 16 and 18 enables the level of the superconducting fluid to be kept substantially away from the rotating member.", "Thus, the rotating member and upper portions of bearing blocks 16 and 18 may be mounted in a vacuum to enable ultra-high rotating speeds.", "It has been found that bearings blocks 16 and 18 will obtain Type II superconducting properties when pedestals 20 are immersed in liquid nitrogen, even when such immersion occurs at a substantial distance from the bearing blocks.", "Referring now to FIGS. 5-7, shown therein are schematic diagrams of systems for imparting rotational motion to rotor 10.", "In FIG. 5, a two coil system is shown wherein magnet 36 is caused to rotate by the imposition of an ac current in the two coils, with the phase in one coil being related to the other by a cosine function.", "In FIG. 6, a three coil drive system is shown wherein the coils are placed at 120° intervals and are driven 120° out of phase with each other.", "In FIG. 7, a four coil drive is shown with each coil being driven 90° out of phase with the other to create a rotating field which again imparts rotational movement to rotor 10.", "While each of the above rotational systems involves the use of electromagnetic energy, rotor 10 could also be rotated through the use of a high pressure gas jet pointed at a circumferential portion of rotor 10 which has been serrated or has emplaced thereon, turbine blades.", "Referring now to FIGS. 8(a), 8(b) and 8(c), a circular Type II superconducting bearing structure 72 is illustrated which includes an orifice 73 enclosing each extremity of rotor 10.", "As with the system shown in FIG. 1, rotor 10 includes magnets 70 at each of its extremities.", "In this configuration, the rotor/bearing assembly can be operated in any orientation with respect to gravity (e.g. see FIG. 8(c)).", "In FIGS. 9(a) and 9(b), further alternative bearing embodiments are shown.", "In FIG. 9(a), magnets 70 have been replaced by ring magnets which encircles a pedestal 82 emanating from the center of bearing block 80.", "In FIG. 9(b), each of magnets 70 is replaced by a magnet with a concave indentation which mates with a conical pedestal emanating from bearing block 80.", "EXAMPLE Several pairs of YBa 2 Cu 3 O x bearing blocks, 1.5 cm in diameter were made by a sintering process at 950° C. in air.", "The crystals were randomly oriented and the specimen required a post anneal treatment in pressurized oxygen (20 bars) at 800° C. for 2 hours in order to obtain a Tc greater than 90° Kelvin.", "Some of the bearing blocks were shaped as shown in FIGS. 1-3.", "Using a Hall effect probe, normal flux density measurements could be made on the surface of the superconductor underneath a levitated permanent magnet.", "When the permanent magnet dipole was parallel to the ceramic bearing surface, normal flux surface measurements were of the order of 0.07 Tesla.", "The sign of the normal flow indicated that two superconducting eddy current vortices were active in the superconductor, one near each of the two magnets'", "poles.", "The surface field measurement also indicated that incomplete flux exclusion was in effect during levitation which is typical of Type II superconductors.", "There was considerable hysteretic behavior in the levitation level of the rotor.", "For small perturbation forces, the levitated rotor exhibited lateral and vertical stiffness.", "The rotor was spun by a magnetic field created by nearby coils.", "No discernible effect by the alternating field on the superconductor or the levitation height was observed with and without rotation.", "At low frequencies, however (1-4 Hz), periodic magnetic forces excited the magnetic stiffness modes through a resonance which sometimes evicted the rotor off the superconducting bearing pads.", "At higher frequencies, lock-in of the rotor speed and driving field frequency occurred and permitted increase of the rotor speed to over 12,000 rpm.", "The low frequency instability was readily overcome by rapidly moving the rotor through the resonant frequencies by substantial application of the energizing field.", "It is surmised that flux pinning creates the hysteretic effects of the magnetic forces on the rotor.", "Nevertheless, the rotor once in position maintains a stable position, unless pushed out of it by an external force.", "It should be understood that the foregoing description is only illustrative of the invention.", "Various alternatives and modifications can be devised by those skilled in the art without departing from the invention.", "Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims." ]
PRIORITY CLAIM This application claims priority from U.S. provisional application serial No. 60/195,212, filed Apr. 7, 2000, the contents of which are incorporated herein by reference. FIELD OF THE INVENTION This invention relates to instruments, particularly medical and research instruments that are used for assessing gas volumes of air cavities, particularly, air cavities that may exhibit a compliance to changes in pressure, such as in vivo volumes of the lung, thorax, oropharynx and/or nasopharynx. BACKGROUND OF THE INVENTION Over the years, a number of methods have been used to determine the functional residual capacity (FRC) of the lung and related thoracic gas measures of a patient. These methods have involved gas dilution techniques, body plethysmography, and radiographic techniques. Gas dilution techniques require the patient to inhale special gases and necessitate special ventilation facilities (see, for example, U.S. Pat. No. 6,139,506). Radiographic techniques require a patient to be exposed to radiation. Additionally, static chest wall and abdominal composure by the patient is required during imaging. Plethysmography requires enclosing the patient or most of the patient's body (see, for example, U.S. Pat. Nos. 5,513,648 and 5,159,935) in a sealed enclosure or at the very least outfitting the patient with impedance belts about the torso (see, for example, U.S. Pat. No. 5,857,459). For these methods, lung pressurization maneuvers are performed by the patient during which changes in lung volume are simultaneously assessed by the plethysmograph. The general gas equation, relating pressure and volume and changes in pressure and volume, is used to determine the unknown volume. Current plethysmographic techniques to assess thoracic gas volume suffer from artifacts due to stomach gas, which causes compliance during testing maneuvers. A method to estimate “trapped” air volume (not absolute volume) in lung of paralyzed patients has been proposed by obtaining a volume/pressure curve upon forced ventilation of the patient's lung (see U.S. Pat. No. 4,844,085). The large volume of gas exchange with this method introduces errors that must be compensated and the forced pressurization/de-pressurization precludes normal breathing of the patient during testing. None of the above methods allow convenient isolation and measurement of the volume of the oral cavity and nasal pharynx. U.S. Pat. No. 5,937,854 discloses a method and apparatus for ventilator pressure and optimization by administering fixed stepwise pressure changes to the lungs of a patient and measuring the lung volume change resulting from each pressure change. The lung volume change is measured by using the RIP technique. This utilizes two elastic cloth bands containing insulated wires, which encircle the patient's rib cage and abdomen and are connected to an oscillator module. OBJECTS AND ADVANTAGES It is accordingly a principal object of the present invention to provide a non-invasive device and method for measuring in vivo gas volumes of a patient, including lung and pharyngeal volumes and, particularly, to obtain volume measurement in the presence of compliance. An additional object of the present invention is to provide an inexpensive device and method that measures the lung volume of a patient independent of a sealed chamber or ventilated airspace and that does not require outfitting the patient with respiratory bands. A further object of the present invention is to provide a device and method to measure lung and airway volume of a patient by a means that is not dependent upon patient cooperation and participation. In other words, the patient is only required “to breathe” and not to perform specialized pressurization maneuvers to within a certain tolerance. Therefore yet another object of the present invention is to provide a device for measuring the lung volume of the immobile, paralyzed, and “intensive care” or “special care” patient. Accordingly, as will be disclosed in detail below, several advantages of the present invention are the measurement of in vivo volumes with a device that is smaller and more portable than existing systems, a device and method that is less complicated for clinicians and less troublesome for patients, and a device and method that serves a greater patient population, including veterinary applications, than is heretofore possible. SUMMARY OF THE INVENTION The purpose of the present invention is to provide a non-radiographic, noninvasive, portable, and non-confining apparatus for measuring gas volumes of in vivo cavities, including but not limited to lung volume and volumes of the thorax, oral and nasal pharynx. Further, the apparatus does not require sophisticated lung pressurization maneuvers to be performed by the patient or the outfitting of patients with thoracic position transducers. The present invention is intended therefore to serve a comprehensive patient population, including the bedridden, unawake, paralyzed, and sedated patient. Further, the device does not require the patient to inhale special gases or be subjected to imaging radiation. It is recognized that various methods exist for assessing lung volume. The present invention represents improvements in the apparatus of boxless measurement of lung volume that can take the form of several embodiments. The detailed embodiments described herein are taken as representative or exemplary of those in which the improvements of the invention may be incorporated and are not presented as being limited in any manner. The invention is directed to an apparatus for measuring gas volumes of an in vivo cavity of unknown compliance in a subject, particularly a patient comprising: (a) an air cavity with induction means for inducing calibrated volume changes in said air cavity; (b) a means for interfacing said air cavity to the in vivo volume of the subject to be measured; (c) a means connected to said air cavity for measuring air pressure variations; and (d) a control means electrically coupled to said induction means and measuring and processing means for calculating the gas volume in said subject. In one embodiment, the subject is a human patient; in another embodiment the subject is a mammal; in yet another embodiment, the subject is a non-living item with a cavity exhibiting compliance, such as a balloon, a tank containing a bladder, or a tank with an inverted floating cover such as one used to contain hydrogen or natural gas. The apparatus interfaces an air cavity to particularly the patient by means of a facial mask, nasal mask, mouthpiece or tubes. In a preferred embodiment, the interfacing means is a facial mask so that a common air cavity is formed with the patient via the oral and/or nasal orifices. The apparatus includes a respiratory access valve connected to its inner cavity that, when open, permits the patient to exchange air with the external environment in the manner of ordinary breathing (means for interfacing said air cavity to ambient environment) and, when closed, permits artificial pressurization of the cavity by means of a calibrated volume-changing piston (means for inducing volume change). The apparatus includes a calibrated device to assess air pressure changes occurring inside the common air cavity and a device to assess air pressure of the ambient environment. The valve interfaces between the external environment and the inner cavity of the apparatus, and is opened or closed by passive means according to breathing airway pressure of the patient. The valve is constructed in such a manner as to remain open while the patient is in the process of inhaling or exhaling, and to momentarily close during the period of time that the patient is changing breathing modality from exhalation to inhalation, when cavity pressure is beneath the shutter threshold. The pressure change in the system due to the induced change in volume is, in itself, insufficient to open the valve. The invention is also directed to a method for measuring a gas volume of an in vivo cavity in a subject utilizing the apparatus of the present invention comprising (a) attaching said apparatus to said subject; (b) measuring the barometric pressure in an area near the subject; (c) measuring changes in induced pressure and volume in said cavity during an induction and preferably at least two inductions, and (d) calculating said gas volume. The method may further comprise the step of calculating compliance of said cavity where compliance is present. The control and processing unit monitors system pressure during the breathing cycle and is therefore programmed to determine if pressure is negative (indicating inhalation), positive (exhalation), or zero (peak of inhalation or trough of exhalation). When the processing and control unit assess that air cavity pressure is within the range that the respiratory valve has become closed and, further, that the breathing cycle is at the trough of exhalation, the control unit repositions the piston and thereby decreases the system volume by a small, known amount. Those versed in the art comprehend that pressure and volume of gas in a closed mass system are mathematically related by the general gas equation. Specifically, the pressure-volume product of the system gas prior to piston movement is equal to the pressure-volume product after piston movement, for the same gas temperature. Compliance occurs whenever the volume under test changes as a result of increased inner forces due to pressurization of the air cavity. Possible sources of compliance are cheeks and lung wall. Of particular note is compliance of the lung wall due to stomach gas, which is an artifact of body plethysmography of all types. Those versed in the art will appreciate the difficulty of measuring a volume under the circumstances in which that volume might adjust itself to the increased pressure created by the measurement process. The invention proposes a means of determining compliance in the course of testing by applying a plurality of different induced gas volumes that result in different pressure measurements from which in vivo volume may be determined. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1 D schematically show the invention in the various states of its operational cycle as described herein in the EXAMPLES. FIG. 2 shows a typical embodiment of the invention. FIG. 3 shows a second embodiment of the invention with added monitoring components. DETAILED DESCRIPTION OF THE INVENTION To enhance understanding of the present invention, it is noted here that the formulae used to determine system volume are identical to those used by the clinically prevalent method of whole body plethysmography. In the case of whole body plethysmography, a change in system volume is created by the patient, by panting against a valve that has been closed at the trough of inhalation during a normal breathing cycle. The resulting changes in lung volume that occur during the panting maneuver are determined by solving a similar formula for the closed air cavity that exists between the patient and the inner box. The estimates of volume change thus obtained are used in the gas-volume equation to determine an estimate of lung volume. In the case of the present invention, the change in induced volume is known precisely since it is supplied in metered portions to the in vivo volume under test, and does not require estimation by a separate plethysmograph. Thus, patient participation and cooperation is minimized in the present invention when testing for thoracic gas volume. In a typical embodiment, the apparatus shown in FIG. 2 is interfaced to the patient, with facemask 20 forming an airtight seal between the inner cavity of the apparatus 21 and in vivo air volume of the patient. Normal breathing by the patient is vented through valve 22 . Valve 22 interfaces between the external environment and inner cavity 21 of the apparatus and is opened or closed by passive means according to breathing pressure of the patient. The processing and control unit 23 monitors the pressure of the system via pressure transducer 24 . The processing and control unit (PCU) also drives linear motor 25 at the appropriate time to move piston 26 a calibrated amount. Pressure changes monitored by transducer 24 from two or more system cycles are processed by PCU 23 as described in the EXAMPLES to display the calculated volume and compliance. In an alternative embodiment shown in FIG. 3, a valve 30 controlled by PCU 23 replaces passive valve 22 shown in the embodiment of FIG. 2. A control signal from PCU 23 signals the valve to vent the apparatus cavity to atmosphere when a preset differential pressure between system and atmosphere exists. This differential pressure is created by a pneumotach screen 31 located in the air stream of valve 30 . A pulse monitor 33 interfaces to PCU 23 allowing each induced volume change to occur at the same phase in the heart cycle. Pneumotach screen 31 serves a further purpose in the alternative embodiment. It may be desirable to obtain measurements of volume at successively occurring troughs of the breathing cycle to enhance accuracy via signal averaging. However, the amount of air in the lungs at the trough of the breathing cycle, FRC, is slightly different for each cycle, even during ordinary breathing. Pneumotach screen 31 and differential pressure transducer 24 permit measurement of volumetric air flow during breathing, so that corrections to lung volume V 0 can be made during the averaging process. Volumetric air flow measurements via pneumotach screen 31 and differential pressure transducer 24 are calibrated prior to patient testing using known air flow values and other standards common to the industry. Therefore, the apparatus of the present invention further comprises means for measurement of volumetric air flow during breathing. EXAMPLES To facilitate understanding of the operation of the invention, a schematic drawing of a general embodiment of the invention is shown in FIGS. 1A to 1 D. The apparatus is shown interfaced to an air cavity 1 of unknown volume V 0 to be determined, containing a compliant wall 2 shown figuratively as a movable piston backed by a spring. A cylinder 3 fitted with, for example, a piston 4 contains a pre-determined volume 5 that communicates with air cavity 1 . The induction means may also be an acoustic speaker, gas mass injection or dilution. A pressure-measuring device 6 is coupled to the combined air cavity and contains transducer, offset, gain, calibration adjustment, and other instrumentation components common to the industry. Operation of the embodiment shown in FIG. 1 begins with calibration of pressure-measuring device 6 , using calibration equipment and techniques common to the industry. When accomplished, pressure-measuring device 6 will directly assess air pressure in a standard unit of absolute measure, such as centimeters of water. At the start of the cycle, piston 4 is situated as shown in FIG. 1A, such that a small volume V f 5 is defined in cylinder 3 . The vent valve 7 is initially open such that the pressure of the system is atmospheric. In FIG. 1B, valve 7 is closed and piston 4 is pushed inward. Pressure in the combined cavity is increased from P 0 to P by virtue of the piston displacement, according to physical laws governing gas within a closed mass system. In turn, a sympathetic increase in volume, V c 8 , occurs due to the compliance of wall 2 in cavity 1 . Volume of the combined air cavity thus changes from V 0 +V f in FIG. 1A to V 0 +V c in FIG. 1 B. If the total change in system volume is known, the volume V 0 can be computed from Boyle's gas equation, V 0 =ΔV[P 0 /(P−P 0 )] where ΔV=V f −V c (P/P 0 ). In a non-compliant system, V c =0, ΔV=V f , and the original volume V 0 can be directly determined. In a compliant system, however, V c ≠0, and the value for volume obtained by directly applying the gas equation is incorrect. Since V c is unknown, sufficient information is yet unavailable to determine V 0 directly whenever compliance is present in the system. In order to determine if compliance is present in the volume under test, the cycle is repeated using a different piston chamber volume V f ′≠V f (FIGS. 1 C and 1 D). The mass of the system has now changed so that the gas equation results in an independent system equation from which volume can again be computed from the new measured change in pressure P′−P 0 . In the event that the computed volume is different than that calculated from performing the previous maneuver, compliance has been determined to exist and contributions to the system volume due to V c must be acknowledged. Although neither V c or V c ′ is known, compliance may be assumed linear when changes in pressure occur that are small relative to atmospheric. In other words, a compliance parameter C may be defined, where V c =C (P−P 0 ) and V c ′=C (P′−P 0 ). Thus, the two independent system equations can be written in terms of P 0 , P, P′, V f , V f ′, C, and V 0 , where the first five of these terms are known by way of measurement and the latter two are the unknown parameters of the system. By techniques familiar to those skilled in the art, C and V 0 can be determined by various numerical means, including methods of linear diagonalization and methods of variance, depending upon the degree of sensitivity among terms. The volume of air 1 in FIG. 1A is at a constant (body) temperature prior to the movement of piston 4 in FIG. 1 B. Small changes in gas temperature occur due to movement of piston 4 because of gas compression. The effect of temperature change can be neglected whenever sufficient time is allowed for temperature of the gas to dissipate in the tissues of the body prior to pressure data collection. In the case of in vivo volumes such as lung, this time period is very short (less than 500 ms) due to the large surface area and efficient heat transfer characteristics of lung tissue. Alternately, if rapid sampling is required, such as for purposes of data averaging, effects of temperature may be accommodated by including temperature terms into the general gas equation, P 0 (V 0 +V f )/T 0 =P(V 0 +V c )/T, where temperature is measured by a transducer with a sufficiently high frequency response and sensitivity adapted into pressure transducer 6 . Operation of a typical embodiment of the apparatus shown in FIG. 2 begins with calibration of pressure transducer 24 as described above. The apparatus is interfaced to the patient, with face mask 20 forming an airtight seal between the inner cavity of the apparatus 21 and in vivo air volume of the patient. This results in a combined air cavity of yet unknown volume, V 0 . Normal breathing by the patient is vented through valve 22 . The valve interfaces between the external environment and the inner cavity of the apparatus, and is opened or closed by passive means according to breathing pressure of the patient. The valve is constructed in such a manner as to remain open while the patient is in the process of inhaling or exhaling and to momentarily close during the time the patient is changing breathing modality from exhalation to inhalation, when cavity pressure is beneath the shutter threshold. The pressure change in the system due to the induced change in volume is, in itself, insufficient to open the valve. The processing and control unit 23 monitors the pressure of the system via pressure transducer 24 , which will be atmospheric at the trough of the breathing cycle. At that moment, the passive valve is closed, sealing the system. The processing and control unit (PCU) signals linear motor 25 to move piston 26 a calibrated amount, inducing a volume change in the system by an amount V f 27 . After a suitable settling time, PCU 23 measures the system pressure via transducer 24 . This procedure provides measures of V f , P 0 , P and a preliminary estimate for V 0 as described in previous paragraphs. The sequence is repeated except that PCU 23 causes piston 26 to induce a different volume V f ′. PCU 23 thus obtains additional measures of V f ′, P 0 , P′ and a second estimate for V 0 to determine (a) if compliance exists in the system and (b) measures of V 0 and the compliance parameter C as described above. Calculated values for V 0 and C are displayed by a digital display unit on PCU 23 . Several breath cycles may be monitored for purposes of averaging. In a practical application of the apparatus, when measuring complex and dynamic volumes such as the human lung, sources of artifact, in addition to that introduced by compliance, are often problematic. One potential problem is associated with the small changes in lung volume that eventuate by blood being forced into the lung by the heart. Although this volume change is very small in relation to the volume of the lung, it may be appreciable in relation to the volume change induced to the system by the apparatus by which measures are obtained. The volumetric action of the heart on the lung wall creates a similar source of change in system pressure. FIG. 3 shows an alternative embodiment of the invention with components added which address these physiologic phenomena. A valve 30 controlled by PCU 23 replaces passive valve 22 shown in the embodiment of FIG. 2. A control signal from PCU 23 signals the valve to vent the apparatus cavity to atmosphere when a preset differential pressure between system and atmosphere exists. A pneumotach screen 31 provides a small resistance to airflow in and out of the mask to allow transducer 24 in conjunction with PCU 23 to monitor flow and thus control valve 30 as noted. Utilization of an active valve in the alternative embodiment of the apparatus facilitates management of the system measuring process and provides surety to PCU 23 about valve status. At the trough of the breathing cycle, control signals from PCU 23 close valve 30 and signal motor 25 to drive piston 26 in such a manner to induce a known increase to system volume. This increase results in a decrease in pressure of the system, instead of an increased pressure as in the case of the previous embodiment. Utilizing a reduced system pressure in the alternative embodiment reduces the tendency for involuntary glottal closure that might otherwise result due to excitation of supralaryngeal baroreceptors during pressurization. A pulse monitoring means, provided by a pulse monitor 33 , allows each induced volume change to occur at the same phase in the heart cycle, thereby reducing the volume artifact caused by blood flow into and out of the lung and the artifact generated by the heart pushing on the wall of the lung. The total system pressure is monitored by transducer 24 and processed by PCU 23 such that slowly-varying pressure artifacts induced by the sources described above can be reduced either by filtering or by providing control feedback to piston 26 in such a manner to continually move it in a fashion to oppose pressure artifacts. A glottal monitoring means, provided by the glottal monitor 32 (an electroglottograph or similar device), monitors the status of the glottis to determine which volume is being measured. When the glottis is closed, the volume being measured is that of the pharnyx. A nasal mask can replace the facemask for use in measuring the nasal pharynx, and the difference between the two measures provides the volume of the orapharynx. For this measurement, the patient's velum must be closed as occurs during swallowing. In addition to measuring volumes of these cavities, taking volume measurements of the lung at the peak of the breathing cycle provides PCU 23 with information required to determine spirometric measures such as functional expired volume (FEV) in addition to the volume obtained at the trough of the breathing cycle, which is functional residual capacity (FRC). Calibration of the pneumotach formed by the resistance screen 31 located in valve 22 permits measures of volumetric air flow by PCU 23 , thus facilitating averaging of calculated in vivo volume measurements obtained over successive breathing cycles. The specific embodiments herein disclosed are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. Various references are cited herein, the disclosures of which are incorporated by reference in their entireties.
This invention relates to instruments, particularly medical and research instruments that are used for assessing gas volumes of cavities, particularly, cavities that may exhibit a compliance to changes in pressure, such as in vivo volumes of the lung, thorax, oropharynx and/or nasopharynx.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "PRIORITY CLAIM This application claims priority from U.S. provisional application serial No. 60/195,212, filed Apr. 7, 2000, the contents of which are incorporated herein by reference.", "FIELD OF THE INVENTION This invention relates to instruments, particularly medical and research instruments that are used for assessing gas volumes of air cavities, particularly, air cavities that may exhibit a compliance to changes in pressure, such as in vivo volumes of the lung, thorax, oropharynx and/or nasopharynx.", "BACKGROUND OF THE INVENTION Over the years, a number of methods have been used to determine the functional residual capacity (FRC) of the lung and related thoracic gas measures of a patient.", "These methods have involved gas dilution techniques, body plethysmography, and radiographic techniques.", "Gas dilution techniques require the patient to inhale special gases and necessitate special ventilation facilities (see, for example, U.S. Pat. No. 6,139,506).", "Radiographic techniques require a patient to be exposed to radiation.", "Additionally, static chest wall and abdominal composure by the patient is required during imaging.", "Plethysmography requires enclosing the patient or most of the patient's body (see, for example, U.S. Pat. Nos. 5,513,648 and 5,159,935) in a sealed enclosure or at the very least outfitting the patient with impedance belts about the torso (see, for example, U.S. Pat. No. 5,857,459).", "For these methods, lung pressurization maneuvers are performed by the patient during which changes in lung volume are simultaneously assessed by the plethysmograph.", "The general gas equation, relating pressure and volume and changes in pressure and volume, is used to determine the unknown volume.", "Current plethysmographic techniques to assess thoracic gas volume suffer from artifacts due to stomach gas, which causes compliance during testing maneuvers.", "A method to estimate “trapped”", "air volume (not absolute volume) in lung of paralyzed patients has been proposed by obtaining a volume/pressure curve upon forced ventilation of the patient's lung (see U.S. Pat. No. 4,844,085).", "The large volume of gas exchange with this method introduces errors that must be compensated and the forced pressurization/de-pressurization precludes normal breathing of the patient during testing.", "None of the above methods allow convenient isolation and measurement of the volume of the oral cavity and nasal pharynx.", "U.S. Pat. No. 5,937,854 discloses a method and apparatus for ventilator pressure and optimization by administering fixed stepwise pressure changes to the lungs of a patient and measuring the lung volume change resulting from each pressure change.", "The lung volume change is measured by using the RIP technique.", "This utilizes two elastic cloth bands containing insulated wires, which encircle the patient's rib cage and abdomen and are connected to an oscillator module.", "OBJECTS AND ADVANTAGES It is accordingly a principal object of the present invention to provide a non-invasive device and method for measuring in vivo gas volumes of a patient, including lung and pharyngeal volumes and, particularly, to obtain volume measurement in the presence of compliance.", "An additional object of the present invention is to provide an inexpensive device and method that measures the lung volume of a patient independent of a sealed chamber or ventilated airspace and that does not require outfitting the patient with respiratory bands.", "A further object of the present invention is to provide a device and method to measure lung and airway volume of a patient by a means that is not dependent upon patient cooperation and participation.", "In other words, the patient is only required “to breathe”", "and not to perform specialized pressurization maneuvers to within a certain tolerance.", "Therefore yet another object of the present invention is to provide a device for measuring the lung volume of the immobile, paralyzed, and “intensive care”", "or “special care”", "patient.", "Accordingly, as will be disclosed in detail below, several advantages of the present invention are the measurement of in vivo volumes with a device that is smaller and more portable than existing systems, a device and method that is less complicated for clinicians and less troublesome for patients, and a device and method that serves a greater patient population, including veterinary applications, than is heretofore possible.", "SUMMARY OF THE INVENTION The purpose of the present invention is to provide a non-radiographic, noninvasive, portable, and non-confining apparatus for measuring gas volumes of in vivo cavities, including but not limited to lung volume and volumes of the thorax, oral and nasal pharynx.", "Further, the apparatus does not require sophisticated lung pressurization maneuvers to be performed by the patient or the outfitting of patients with thoracic position transducers.", "The present invention is intended therefore to serve a comprehensive patient population, including the bedridden, unawake, paralyzed, and sedated patient.", "Further, the device does not require the patient to inhale special gases or be subjected to imaging radiation.", "It is recognized that various methods exist for assessing lung volume.", "The present invention represents improvements in the apparatus of boxless measurement of lung volume that can take the form of several embodiments.", "The detailed embodiments described herein are taken as representative or exemplary of those in which the improvements of the invention may be incorporated and are not presented as being limited in any manner.", "The invention is directed to an apparatus for measuring gas volumes of an in vivo cavity of unknown compliance in a subject, particularly a patient comprising: (a) an air cavity with induction means for inducing calibrated volume changes in said air cavity;", "(b) a means for interfacing said air cavity to the in vivo volume of the subject to be measured;", "(c) a means connected to said air cavity for measuring air pressure variations;", "and (d) a control means electrically coupled to said induction means and measuring and processing means for calculating the gas volume in said subject.", "In one embodiment, the subject is a human patient;", "in another embodiment the subject is a mammal;", "in yet another embodiment, the subject is a non-living item with a cavity exhibiting compliance, such as a balloon, a tank containing a bladder, or a tank with an inverted floating cover such as one used to contain hydrogen or natural gas.", "The apparatus interfaces an air cavity to particularly the patient by means of a facial mask, nasal mask, mouthpiece or tubes.", "In a preferred embodiment, the interfacing means is a facial mask so that a common air cavity is formed with the patient via the oral and/or nasal orifices.", "The apparatus includes a respiratory access valve connected to its inner cavity that, when open, permits the patient to exchange air with the external environment in the manner of ordinary breathing (means for interfacing said air cavity to ambient environment) and, when closed, permits artificial pressurization of the cavity by means of a calibrated volume-changing piston (means for inducing volume change).", "The apparatus includes a calibrated device to assess air pressure changes occurring inside the common air cavity and a device to assess air pressure of the ambient environment.", "The valve interfaces between the external environment and the inner cavity of the apparatus, and is opened or closed by passive means according to breathing airway pressure of the patient.", "The valve is constructed in such a manner as to remain open while the patient is in the process of inhaling or exhaling, and to momentarily close during the period of time that the patient is changing breathing modality from exhalation to inhalation, when cavity pressure is beneath the shutter threshold.", "The pressure change in the system due to the induced change in volume is, in itself, insufficient to open the valve.", "The invention is also directed to a method for measuring a gas volume of an in vivo cavity in a subject utilizing the apparatus of the present invention comprising (a) attaching said apparatus to said subject;", "(b) measuring the barometric pressure in an area near the subject;", "(c) measuring changes in induced pressure and volume in said cavity during an induction and preferably at least two inductions, and (d) calculating said gas volume.", "The method may further comprise the step of calculating compliance of said cavity where compliance is present.", "The control and processing unit monitors system pressure during the breathing cycle and is therefore programmed to determine if pressure is negative (indicating inhalation), positive (exhalation), or zero (peak of inhalation or trough of exhalation).", "When the processing and control unit assess that air cavity pressure is within the range that the respiratory valve has become closed and, further, that the breathing cycle is at the trough of exhalation, the control unit repositions the piston and thereby decreases the system volume by a small, known amount.", "Those versed in the art comprehend that pressure and volume of gas in a closed mass system are mathematically related by the general gas equation.", "Specifically, the pressure-volume product of the system gas prior to piston movement is equal to the pressure-volume product after piston movement, for the same gas temperature.", "Compliance occurs whenever the volume under test changes as a result of increased inner forces due to pressurization of the air cavity.", "Possible sources of compliance are cheeks and lung wall.", "Of particular note is compliance of the lung wall due to stomach gas, which is an artifact of body plethysmography of all types.", "Those versed in the art will appreciate the difficulty of measuring a volume under the circumstances in which that volume might adjust itself to the increased pressure created by the measurement process.", "The invention proposes a means of determining compliance in the course of testing by applying a plurality of different induced gas volumes that result in different pressure measurements from which in vivo volume may be determined.", "BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1 D schematically show the invention in the various states of its operational cycle as described herein in the EXAMPLES.", "FIG. 2 shows a typical embodiment of the invention.", "FIG. 3 shows a second embodiment of the invention with added monitoring components.", "DETAILED DESCRIPTION OF THE INVENTION To enhance understanding of the present invention, it is noted here that the formulae used to determine system volume are identical to those used by the clinically prevalent method of whole body plethysmography.", "In the case of whole body plethysmography, a change in system volume is created by the patient, by panting against a valve that has been closed at the trough of inhalation during a normal breathing cycle.", "The resulting changes in lung volume that occur during the panting maneuver are determined by solving a similar formula for the closed air cavity that exists between the patient and the inner box.", "The estimates of volume change thus obtained are used in the gas-volume equation to determine an estimate of lung volume.", "In the case of the present invention, the change in induced volume is known precisely since it is supplied in metered portions to the in vivo volume under test, and does not require estimation by a separate plethysmograph.", "Thus, patient participation and cooperation is minimized in the present invention when testing for thoracic gas volume.", "In a typical embodiment, the apparatus shown in FIG. 2 is interfaced to the patient, with facemask 20 forming an airtight seal between the inner cavity of the apparatus 21 and in vivo air volume of the patient.", "Normal breathing by the patient is vented through valve 22 .", "Valve 22 interfaces between the external environment and inner cavity 21 of the apparatus and is opened or closed by passive means according to breathing pressure of the patient.", "The processing and control unit 23 monitors the pressure of the system via pressure transducer 24 .", "The processing and control unit (PCU) also drives linear motor 25 at the appropriate time to move piston 26 a calibrated amount.", "Pressure changes monitored by transducer 24 from two or more system cycles are processed by PCU 23 as described in the EXAMPLES to display the calculated volume and compliance.", "In an alternative embodiment shown in FIG. 3, a valve 30 controlled by PCU 23 replaces passive valve 22 shown in the embodiment of FIG. 2. A control signal from PCU 23 signals the valve to vent the apparatus cavity to atmosphere when a preset differential pressure between system and atmosphere exists.", "This differential pressure is created by a pneumotach screen 31 located in the air stream of valve 30 .", "A pulse monitor 33 interfaces to PCU 23 allowing each induced volume change to occur at the same phase in the heart cycle.", "Pneumotach screen 31 serves a further purpose in the alternative embodiment.", "It may be desirable to obtain measurements of volume at successively occurring troughs of the breathing cycle to enhance accuracy via signal averaging.", "However, the amount of air in the lungs at the trough of the breathing cycle, FRC, is slightly different for each cycle, even during ordinary breathing.", "Pneumotach screen 31 and differential pressure transducer 24 permit measurement of volumetric air flow during breathing, so that corrections to lung volume V 0 can be made during the averaging process.", "Volumetric air flow measurements via pneumotach screen 31 and differential pressure transducer 24 are calibrated prior to patient testing using known air flow values and other standards common to the industry.", "Therefore, the apparatus of the present invention further comprises means for measurement of volumetric air flow during breathing.", "EXAMPLES To facilitate understanding of the operation of the invention, a schematic drawing of a general embodiment of the invention is shown in FIGS. 1A to 1 D. The apparatus is shown interfaced to an air cavity 1 of unknown volume V 0 to be determined, containing a compliant wall 2 shown figuratively as a movable piston backed by a spring.", "A cylinder 3 fitted with, for example, a piston 4 contains a pre-determined volume 5 that communicates with air cavity 1 .", "The induction means may also be an acoustic speaker, gas mass injection or dilution.", "A pressure-measuring device 6 is coupled to the combined air cavity and contains transducer, offset, gain, calibration adjustment, and other instrumentation components common to the industry.", "Operation of the embodiment shown in FIG. 1 begins with calibration of pressure-measuring device 6 , using calibration equipment and techniques common to the industry.", "When accomplished, pressure-measuring device 6 will directly assess air pressure in a standard unit of absolute measure, such as centimeters of water.", "At the start of the cycle, piston 4 is situated as shown in FIG. 1A, such that a small volume V f 5 is defined in cylinder 3 .", "The vent valve 7 is initially open such that the pressure of the system is atmospheric.", "In FIG. 1B, valve 7 is closed and piston 4 is pushed inward.", "Pressure in the combined cavity is increased from P 0 to P by virtue of the piston displacement, according to physical laws governing gas within a closed mass system.", "In turn, a sympathetic increase in volume, V c 8 , occurs due to the compliance of wall 2 in cavity 1 .", "Volume of the combined air cavity thus changes from V 0 +V f in FIG. 1A to V 0 +V c in FIG. 1 B. If the total change in system volume is known, the volume V 0 can be computed from Boyle's gas equation, V 0 =ΔV[P 0 /(P−P 0 )] where ΔV=V f −V c (P/P 0 ).", "In a non-compliant system, V c =0, ΔV=V f , and the original volume V 0 can be directly determined.", "In a compliant system, however, V c ≠0, and the value for volume obtained by directly applying the gas equation is incorrect.", "Since V c is unknown, sufficient information is yet unavailable to determine V 0 directly whenever compliance is present in the system.", "In order to determine if compliance is present in the volume under test, the cycle is repeated using a different piston chamber volume V f ′≠V f (FIGS.", "1 C and 1 D).", "The mass of the system has now changed so that the gas equation results in an independent system equation from which volume can again be computed from the new measured change in pressure P′−P 0 .", "In the event that the computed volume is different than that calculated from performing the previous maneuver, compliance has been determined to exist and contributions to the system volume due to V c must be acknowledged.", "Although neither V c or V c ′ is known, compliance may be assumed linear when changes in pressure occur that are small relative to atmospheric.", "In other words, a compliance parameter C may be defined, where V c =C (P−P 0 ) and V c ′=C (P′−P 0 ).", "Thus, the two independent system equations can be written in terms of P 0 , P, P′, V f , V f ′, C, and V 0 , where the first five of these terms are known by way of measurement and the latter two are the unknown parameters of the system.", "By techniques familiar to those skilled in the art, C and V 0 can be determined by various numerical means, including methods of linear diagonalization and methods of variance, depending upon the degree of sensitivity among terms.", "The volume of air 1 in FIG. 1A is at a constant (body) temperature prior to the movement of piston 4 in FIG. 1 B. Small changes in gas temperature occur due to movement of piston 4 because of gas compression.", "The effect of temperature change can be neglected whenever sufficient time is allowed for temperature of the gas to dissipate in the tissues of the body prior to pressure data collection.", "In the case of in vivo volumes such as lung, this time period is very short (less than 500 ms) due to the large surface area and efficient heat transfer characteristics of lung tissue.", "Alternately, if rapid sampling is required, such as for purposes of data averaging, effects of temperature may be accommodated by including temperature terms into the general gas equation, P 0 (V 0 +V f )/T 0 =P(V 0 +V c )/T, where temperature is measured by a transducer with a sufficiently high frequency response and sensitivity adapted into pressure transducer 6 .", "Operation of a typical embodiment of the apparatus shown in FIG. 2 begins with calibration of pressure transducer 24 as described above.", "The apparatus is interfaced to the patient, with face mask 20 forming an airtight seal between the inner cavity of the apparatus 21 and in vivo air volume of the patient.", "This results in a combined air cavity of yet unknown volume, V 0 .", "Normal breathing by the patient is vented through valve 22 .", "The valve interfaces between the external environment and the inner cavity of the apparatus, and is opened or closed by passive means according to breathing pressure of the patient.", "The valve is constructed in such a manner as to remain open while the patient is in the process of inhaling or exhaling and to momentarily close during the time the patient is changing breathing modality from exhalation to inhalation, when cavity pressure is beneath the shutter threshold.", "The pressure change in the system due to the induced change in volume is, in itself, insufficient to open the valve.", "The processing and control unit 23 monitors the pressure of the system via pressure transducer 24 , which will be atmospheric at the trough of the breathing cycle.", "At that moment, the passive valve is closed, sealing the system.", "The processing and control unit (PCU) signals linear motor 25 to move piston 26 a calibrated amount, inducing a volume change in the system by an amount V f 27 .", "After a suitable settling time, PCU 23 measures the system pressure via transducer 24 .", "This procedure provides measures of V f , P 0 , P and a preliminary estimate for V 0 as described in previous paragraphs.", "The sequence is repeated except that PCU 23 causes piston 26 to induce a different volume V f ′.", "PCU 23 thus obtains additional measures of V f ′, P 0 , P′ and a second estimate for V 0 to determine (a) if compliance exists in the system and (b) measures of V 0 and the compliance parameter C as described above.", "Calculated values for V 0 and C are displayed by a digital display unit on PCU 23 .", "Several breath cycles may be monitored for purposes of averaging.", "In a practical application of the apparatus, when measuring complex and dynamic volumes such as the human lung, sources of artifact, in addition to that introduced by compliance, are often problematic.", "One potential problem is associated with the small changes in lung volume that eventuate by blood being forced into the lung by the heart.", "Although this volume change is very small in relation to the volume of the lung, it may be appreciable in relation to the volume change induced to the system by the apparatus by which measures are obtained.", "The volumetric action of the heart on the lung wall creates a similar source of change in system pressure.", "FIG. 3 shows an alternative embodiment of the invention with components added which address these physiologic phenomena.", "A valve 30 controlled by PCU 23 replaces passive valve 22 shown in the embodiment of FIG. 2. A control signal from PCU 23 signals the valve to vent the apparatus cavity to atmosphere when a preset differential pressure between system and atmosphere exists.", "A pneumotach screen 31 provides a small resistance to airflow in and out of the mask to allow transducer 24 in conjunction with PCU 23 to monitor flow and thus control valve 30 as noted.", "Utilization of an active valve in the alternative embodiment of the apparatus facilitates management of the system measuring process and provides surety to PCU 23 about valve status.", "At the trough of the breathing cycle, control signals from PCU 23 close valve 30 and signal motor 25 to drive piston 26 in such a manner to induce a known increase to system volume.", "This increase results in a decrease in pressure of the system, instead of an increased pressure as in the case of the previous embodiment.", "Utilizing a reduced system pressure in the alternative embodiment reduces the tendency for involuntary glottal closure that might otherwise result due to excitation of supralaryngeal baroreceptors during pressurization.", "A pulse monitoring means, provided by a pulse monitor 33 , allows each induced volume change to occur at the same phase in the heart cycle, thereby reducing the volume artifact caused by blood flow into and out of the lung and the artifact generated by the heart pushing on the wall of the lung.", "The total system pressure is monitored by transducer 24 and processed by PCU 23 such that slowly-varying pressure artifacts induced by the sources described above can be reduced either by filtering or by providing control feedback to piston 26 in such a manner to continually move it in a fashion to oppose pressure artifacts.", "A glottal monitoring means, provided by the glottal monitor 32 (an electroglottograph or similar device), monitors the status of the glottis to determine which volume is being measured.", "When the glottis is closed, the volume being measured is that of the pharnyx.", "A nasal mask can replace the facemask for use in measuring the nasal pharynx, and the difference between the two measures provides the volume of the orapharynx.", "For this measurement, the patient's velum must be closed as occurs during swallowing.", "In addition to measuring volumes of these cavities, taking volume measurements of the lung at the peak of the breathing cycle provides PCU 23 with information required to determine spirometric measures such as functional expired volume (FEV) in addition to the volume obtained at the trough of the breathing cycle, which is functional residual capacity (FRC).", "Calibration of the pneumotach formed by the resistance screen 31 located in valve 22 permits measures of volumetric air flow by PCU 23 , thus facilitating averaging of calculated in vivo volume measurements obtained over successive breathing cycles.", "The specific embodiments herein disclosed are intended as illustrations of several aspects of the invention.", "Any equivalent embodiments are intended to be within the scope of this invention.", "Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description.", "Such modifications are also intended to fall within the scope of the appended claims.", "Various references are cited herein, the disclosures of which are incorporated by reference in their entireties." ]
[0001] The present invention relates to a method of controlling a blower system, for use in a powered air purifying respirator (PAPR), in particular, to detect a low air-pressure high airflow event. BACKGROUND [0002] When working in areas where there is known to be, or there is a risk of there being, dusts, fumes or gases that are potentially hazardous or harmful to health, it is usual for the worker to use a respirator. A common type of respirator used in such circumstances is a powered air purifying respirator (PAPR). A PAPR has a blower system comprising a fan powered by an electric motor for delivering a forced flow of air to the respirator user. A turbo unit usually includes a housing that typically contains the blower system, and is adapted to connect a filter to the blower system. [0003] Air is drawn through the filter by the blower system and passed from the turbo unit through a breathing tube to one of a mask, or a contained user environment, such as mask, helmet, hood or suit (where the user is contained within an environment separated from ambient and external conditions) thus providing filtered air to the user's breathing zone (the area around their nose and mouth). A blower system for a PAPR may also include an electronic control unit to regulate the power driving the fan. Typically, a single power supply, for example a battery, provides power for both the fan and the electronic control unit. [0004] Sufficient airflow is required by the user to ensure that the designated level of respiratory protection is maintained. For example, too low an airflow can cause ingress of contaminants into the user's breathing zone. In response to this, the electronic control unit may be used to trigger alarms to the user, for example, to alert the user if the airflow falls below a designated level, or to alert the user that the filters may be blocked with dust and need to be replaced. It is also common for the electronic control unit to trigger an alarm if the battery is depleted to a level where the correct operation of the PAPR is likely to be compromised. [0005] It is desirable that the user of a PAPR can be alerted if an event occurs that takes the operation of the PAPR outside of the defined operation range. This is particularly desirable now that PAPR suit systems are available. If the integrity of a suit is compromised it can often go unnoticed by the user. SUMMARY [0006] The present invention provides a method of controlling a powered air purifying respirator blower system to detect a low air-pressure high airflow event, the system comprising a fan powered by an electric motor, controlled by an electronic control unit for delivering a forced flow of filtered air to a user, and the electronic control unit having a plurality of data points representing events defining an acceptable operating range in terms of different characteristics of the blower system stored therein, the method comprising: sampling a characteristic that represents the operating condition of the blower to obtain a sampled data point; comparing the sampled data point and the stored data point representing a low air-pressure high airflow event, for the same characteristic; repeating the sampling during a fixed time period, and if the comparing step indicates the low air-pressure high airflow event has been reached for the majority of the time period; activating an alarm. [0007] By taking into consideration deviations of the operating condition from the blower system operating range, for example an increase in airflow and/or a decrease in blower system air pressure, the user can be alerted to the situation where the PAPR system has been compromised to allow them to take appropriate action. [0008] Other features of the invention will be apparent from the attached dependent claims. [0009] The present invention provides a method of controlling a powered air purifying respirator blower system where the sampling is carried out by the electronic control unit. [0010] Preferably, the characteristic sampled is one of: voltage across the motor; current through the motor; speed of the motor; or any combination thereof. In this situation the low air-pressure high airflow event is a minimum acceptable value for the characteristic sampled. [0011] The present invention further provides a method of controlling a powered air purifying respirator blower system where the sampling is carried out using a sensor external to the electronic control unit. [0012] The present invention yet further provides a method of controlling a powered air purifying respirator blower system where the characteristic sampled is one of air-pressure or airflow. In the situation where the characteristic is air-pressure, the low air-pressure high airflow event is a minimum acceptable value. Alternatively, in the situation where the characteristic is airflow, the low air-pressure high airflow event is a maximum acceptable value. [0013] The alarm is at least one or more of an audible alarm, a visible alarm, or a vibration alarm. [0014] Preferably, the fixed time period is in the range of 3 to 30 seconds. Preferably, the respirator delivers a substantially uniform volumetric airflow to a user. [0015] Preferably, the respirator operates at one of: a substantially constant current and a substantially constant voltage. [0016] The present invention also provides for the use of a respirator employing a method of controlling a powered air purifying respirator blower system, to deliver a forced flow of filtered air as described above to contained user environment. Preferably, the contained user environment is one of a mask, a helmet or a hood. Alternatively the contained user environment is a suit. BRIEF DESCRIPTION OF THE DRAWINGS [0017] By way of example only, an embodiment of the invention will now described below with reference to the accompanying drawings, in which: [0018] FIG. 1 a is a diagrammatical graph of a constant current operating range; [0019] FIG. 1 b is a diagrammatical graph of a uniform volumetric airflow operating range; [0020] FIG. 2 is a diagrammatical illustration of a powered air purifying respirator; [0021] FIG. 3 shows a block diagram of a blower system for the air purifying respirator of FIG. 3 ; and [0022] FIG. 4 shows a flow diagram of a blower control sequence according an embodiment of the present invention. DETAILED DESCRIPTION [0023] Many electronic control units deliver either a constant current or a constant voltage to the electric motor so that the airflow from the blower system is not affected as the battery is depleted during operation of the PAPR. Some electronic control units control the power to the electric motor with the aim of maintaining a substantially uniform volumetric airflow from the blower system. [0024] Such electronic control units often compensate for both changes in battery voltage and also compensate for changes in the filter pressure drop as the filter clogs with dust or particles. The term “volumetric airflow” indicates the volume of air provided to a user at any one time as opposed to the mass of air provided to a user any one time. [0025] The three types of control systems: constant current; constant voltage; and volumetric airflow, operate using parameters set within defined operating ranges for each of the electrical characteristics of the motor (voltage across the motor, current through the motor and motor power, speed of the motor), as well as for the air-pressure and airflow produced by the motor. FIG. 1 a is a diagrammatical graph of a constant current operating range and FIG. 1 b is a diagrammatical graph of a uniform volumetric airflow operating range. The exemplary constant current controlled blower system operating range is similar to that of a constant voltage operating range. The graph of FIG. 1 a shows that the airflow from the blower system increases as the air-pressure drop across the blower system decreases. The section of the graph marked A represents insufficient airflow to maintain the desired level of respiratory protection. This is the high air-pressure low airflow operating range. The section of the graph between points B and C is the desired operating range where sufficient airflow is delivered to the user to maintain suitable respirator protection. The airflow from a constant current or constant voltage blower system is likely to reduce over time as the pressure drop of the filter connected to the blower increases due to clogging with dust or particles. However, the operating range during the lifetime of the blower will be broadly consistent with the operating range shown. B represents the high air-pressure low airflow event where a low airflow alarm would be triggered. C represents the low air-pressure high airflow event, above which, it is likely that the integrity of the PAPR has been compromised, marked as region D on the graph. The characteristic curve of FIG. 1 b has a flat section between points B and C where the desired operating airflow is uniform and sufficient to maintain suitable respirator protection. The section of the graph marked A representing insufficient airflow to maintain the desired level of respiratory protection is the high air-pressure low airflow operating range. Similar to FIG. 1 a , point C of FIG. 1 b represents the low air-pressure high airflow event, above which, in the region marked D, it is likely that the integrity of the PAPR has been compromised. [0026] If an event occurs that causes the airflow to be reduced or the air-pressure across the blower system to increase (a high air-pressure low airflow event), it is likely that a low airflow alarm will be triggered to alert the user to the fact that they are not receiving sufficient filtered air and that ingress of potentially contaminated air into their breathing zone is likely. However, there is no provision for the triggering of an alarm when an event occurs that causes the air-pressure to drop or the airflow to rise (a low air-pressure high airflow event). [0027] The following are some examples of problems that can arise that are unlikely to trigger an alarm in current PAPR systems. Each of these represents a low air-pressure high airflow event. A failure in the filtering process of a PAPR, such as the filter media being inadvertently damaged or punctured can result in potentially contaminated air to ingress the user's breathing zone. Furthermore, breaches of system integrity such as a filter not being fitted properly, a filter being fitted without a gasket or seal, or a filter becoming removed or partially removed during use may give rise to similar events. If the breathing tube is incorrectly fitted to the mask, helmet, hood or suit, or to the turbo outlet, or becomes disconnected or damaged during use similar events are likely to occur. Likewise, if a local contained user environment, such as a mask, helmet, hood or suit to which the PAPR is attached is torn or damaged or otherwise compromised, a situation where potentially contaminated air may ingress the users breathing zone may occur. In addition, if any mask, helmet, hood or suit is removed during use and the PAPR turbo is left running, current commercially available PAPRs do not trigger an alarm. [0028] The present invention is based on the realization that currently known methods of controlling a blower system currently employed in PAPRs do not trigger an alarm when the PAPRs integrity is compromised as described above. Furthermore, it has been realised that the above described problems result in the blower system developing a high airflow low air-pressure event and as such the blower system parameters can be used to provide the electronic control unit with information about the environment that the blower system is operating within and more particularly information about a contained user environment, such as a mask (for example, a full face respirator mask, a half face respirator mask, and so on.), helmet, hood or suit that the blower system is supplying. Such an event may also sometimes be referred to as indicating a breach in the integrity of the contained user environment. [0029] One exemplary embodiment of the present invention described below employs a turbo as shown in FIG. 2 . FIG. 2 is a diagrammatical illustration of a powered air purifying respirator. The air purifying respirator shown is a volumetric airflow device, but the components would be similar, and sometimes, substantially identical for both the constant voltage and constant current devices mentioned above. The exemplary PAPR comprises a head or a face piece, such as a hood 1 , a turbo unit 2 , a breathing tube 3 , a filter 4 and turbo support, such as a belt 5 . The hood 1 is worn on the user's 6 head. It at least partially encloses the user's 6 head to form a breathing zone 7 , that is, the area around their nose and mouth, so that the filtered air is directed to this breathing zone 7 . The turbo unit 2 may be attached to a belt 5 to enable it to be secured about the user's torso. The turbo unit 2 usually includes a housing (not shown) that houses a blower system (not shown), which draws the air through the PAPR system using a fan (also not shown). The turbo unit 2 supplies air to the hood 1 through the breathing tube 3 which is connected between the outlet 8 of the turbo unit 2 and the inlet 9 of the hood 1 . The turbo unit 2 is fitted with a filter 4 , which can be either inside the turbo unit or attached to the turbo unit as shown in FIG. 2 such that the filter 4 is in the airflow path, preferably disposed upstream of a fan opening of the blower. The purpose of providing the filter 4 is to remove at least a certain amount of particles and/or gases and/or vapours from the ambient air before the air is delivered to the user 6 . The battery pack 10 , which is fitted to the turbo unit 2 provides power to the electronic control unit 18 and to the motor 17 (both shown in FIG. 2 as discussed below). [0030] Although a hood is illustrated in FIG. 2 , the hood 1 could substituted by another head piece or face piece, such as a mask, a helmet or a full suit, provided that a closed user environment, covering at least the original area of the user's face, to direct air to the user's breathing zone 7 , is created. [0031] The following illustrates how the blower system for an air purifying respirator may function. In the following examples, the structural components of the PAPR may be assumed to be as described above with reference to FIGS. 2 and 3 . [0032] FIG. 3 shows a block diagram of a blower system for the air-purifying respirator of FIG. 2 . This blower system is housed within the turbo unit 2 illustrated in FIG. 2 . In accordance with this embodiment of the invention the blower 11 includes a housing 12 having an inlet 13 and an outlet 14 . The blower 11 further includes a fan 15 , having a plurality of blades 16 , driven by a motor 17 . The blower 11 is controlled by an electronic control unit 18 which regulates the power provided to the motor 17 . [0033] With further reference to FIG. 3 , the blower system comprises an electronic control unit 18 that functions to maintain a substantially uniform, preferably constant, volumetric airflow to the hood 1 . The electronic control unit 18 comprises: a microprocessor device 19 , such as a single chip microcontroller, for computing information; a memory device 20 , such as flash RAM, for storing information, for example, calibration data and sensor input receivers 21 a , 21 b , 21 c , for receiving data from sensors such as sensors to detect the voltage across the motor, sensors to detect current through the motor and sensors to detect the speed of the motor. Also included is an output controller 22 , such as a pulse width modulation controller chip, for providing power to the motor 17 and any alarm or status indicators, such as buzzers or light emitting diodes that may be included in the PAPR. The memory device 20 of the electronic control unit 18 has two parts: a fixed memory and a temporary memory. The fixed memory is populated with data, for example, at the time of manufacture, comprising the algorithms and programs for enabling the microprocessor 19 to carry out its calculations and procedures, and calibration information from the factory calibration procedure. The temporary memory is used for storing data and information such as sensor readings and fan and motor operating parameter data collected during start-up and running of the turbo unit 2 . If desired, this data maybe erased when the turbo unit 2 is powered down. [0034] In this embodiment of the present invention speed of the motor and motor voltage are the characteristics chosen to determine the operating condition of the blower system. The speed of the motor may be measured by means of a sensor 23 that is connected to the blower 11 and measures the number of revolutions of the fan 15 in a given time period. A suitable type of sensor for measuring the speed of the motor would be a Hall Effect device, although other types of sensor, for example optical sensors, could be used. The speed of the motor information is received by the microprocessor device 19 of the electronic control unit 18 . The applied voltage 22 to the electric motor 17 may be monitored directly by an input 21 to the microprocessor 19 of the electronic control unit 18 . This means that, in this exemplary embodiment, two of the sensor inputs 21 b , 21 c provided are inactive during this particular method of use, but may be activated if alternative characteristics are chosen. [0035] During the factory setup and calibration of the exemplary blower system, of FIG. 3 , a plurality of data points, including those relating to the operating characteristics described above, (speed of the motor and voltage across the motor), representing events defining an acceptable operating range of the blower 11 may be stored in the fixed memory 20 of the electronic control unit 18 . The stored data points may include data points that represent a low air-pressure high airflow (LPHF) event at the limit of the acceptable operating range (see FIG. 1 b ). [0036] When the blower 11 is started up and during use, the electronic control unit 18 endeavours to maintain a substantially uniform volumetric airflow. The required volumetric airflow may be predetermined during the factory setup. For example the volumetric airflow is preferably in the range of, but not limited to 70 to 250 litres/minute and is dependent on the level of respiratory protection required by the PAPR and the type of mask, helmet, hood or suit used by the PAPR. [0037] More preferably the volumetric airflow is in the range 120 to 220 litres/minute, yet more preferably in the range 160 to 200 litres/minute. During use of the blower 11 the electronic control unit 18 samples data points for the blower system operating characteristics and compares them with the stored data points. If certain predetermined criteria are met the electronic control unit 18 will trigger an alarm 24 to be activated to warn the user that an unacceptable event has occurred. [0038] FIG. 4 shows a flow diagram of a blower system control sequence according to an embodiment of the present invention. In this exemplary embodiment, when the turbo unit 2 is started up, an algorithm stored in the fixed memory 20 of the electronic control unit 18 begins the sampling sequence at step 26 . [0039] The sequence of FIG. 4 is repeated, usually a plurality of times, by the electronic control unit 18 at regular intervals predetermined by the algorithm stored in the fixed memory 20 . For example the interval between consecutive samples is in the range of, but not limited to 2 to 50 ms, more preferably in the range 2 to 20 ms, yet more preferably in the range 2 to 10 ms. A rolling average algorithm is often used in such systems, wherein a plurality of samples are collected and average to reduce the effect of electrical noise in the system. In this embodiment of the present invention a rolling average of 60 samples is used. Each sampled data point is processed as follows. [0040] At step 27 the speed of the motor is measured by the electronic control unit 18 by means of the sensor 23 in the blower 11 and stored in the temporary memory 20 . From the stored speed of the motor data point the electronic control unit 18 calculates the expected motor voltage, at step 28 , for that particular speed of the motor 17 by referring to the stored data points stored in the fixed memory 20 from the calibration of the blower system, and stores the result in the temporary memory 20 . At step 29 the electronic control unit 18 compares the data point in the temporary memory 20 for the expected motor voltage and the motor voltage data points stored in the fixed memory that represent a low air-pressure high airflow (LPHF) event. If the expected motor voltage is higher than the event motor voltage, the electronic control unit proceeds to follow a sequence of steps 30 to check and maintain a substantially uniform airflow and to check for other blower system events. If, however, the expected motor voltage is lower than the event motor voltage, the electronic control unit adjusts the actual motor voltage at step 31 (for example, by means of a pulse width modulation controller) to be equal to the high airflow event motor voltage and starts a high airflow timer, step 32 . The sequence is repeated at regular intervals, as described above. After subsequent data points are sampled, the high airflow timer may either be cancelled or remain active, as appropriate at step 33 . If the timer remains active for a fixed time period at step 34 , indicating that the low air-pressure high airflow (LPHF) condition has been present for the majority of that period, the electronic control unit 18 will trigger to activate an alarm 24 at step 35 to the user. The fixed time period is in the range of, but not limited to 3 to 30 seconds, more preferably in the range 5 to 15 seconds, yet more preferably in the range 8 to 12 seconds. If further data points outside of this time range are sampled and the low air-pressure high airflow (LPHF) event is no longer detected, the alarm is cancelled. Alternatively the alarm may be manually cancelled by the user, for example by turning the PAPR off. [0041] The low air-pressure high airflow alarm 24 according to an embodiment of the present invention may comprise a visual alarm, an audible alarm, a vibration alarm or any combination thereof. The visual alarm is preferably given by means of a light, such as a light emitting diode (LED) or a bulb, that is visible external to the turbo unit. However, the visual alarm may be an alternative type indicator, for example: a warning message; a numeric display or a liquid crystal display (LCD), or another suitable device. The visual alarm may be continuous, intermittent, or display information or coded information to the user. For example, if the visual alarm comprises a light, the light may be flashed intermittently to attract the attention of the user. The audible alarm is preferably given by a piezoelectric device, although alternative types of sounders or buzzers may be used, for example, electro-mechanical buzzers. The audible alarm may be continuous or intermittent, or may be variable in volume and/or in the frequency of the sound produced. For certain applications, such as noisy environments where it may be difficult for the user to hear an audible alarm, it may be desirable to use a vibration alarm such as those commonly found in mobile phones. The vibration alarm may be set to vibrate continuously or intermittently. Each type of alarm may be used alone or in combination with one or more other types of alarm. For example, it may be desirable to operate an intermittent visual alarm and an intermittent audible alarm simultaneously, ensuring that the flashing of the visual alarm occurs contemporaneously with the sounding of the audible alarm. Another exemplary combination may be the use of an audible and a vibration alarm simultaneously. [0042] In the above embodiment, the motor characteristics of speed of the motor and voltage across the motor are used to determine a low air-pressure high airflow event, and measured directly using sensors external to the motor. Alternatively, other characteristics of the blower system representing the operating condition may be used. These may be any electrical characteristics of the blower 11 , giving an indirect measurement of air-pressure and airflow, measured by the electronic control unit 18 or an additional sensor 25 , for example, current through the motor or motor power. However, the physical characteristics of air-pressure or airflow may be measured directly, using sensors 25 , which may be disposed external to the motor 17 . For example, the air-pressure could be measured by a pressure sensor adapted to compare the pressure between the inlet 13 and the outlet 14 of the blower 11 , or airflow could be measured by an airflow sensor positioned in the airflow path at the outlet 14 of the blower 11 . Preferably therefore the characteristic sampled is one of: voltage across the motor; current through the motor; speed of the motor; or any combination thereof. Alternatively the characteristics sampled may be one of air-pressure or airflow. [0043] If the characteristic sampled is one of voltage across the motor 17 ; current through the motor; motor power or speed of the motor, it is likely that the low air-pressure high airflow event is represented by a minimum acceptable value. If the characteristic sampled is air-pressure, then the low air-pressure high airflow event is also represented by a minimum acceptable value. However, if the motor characteristic sampled is airflow, then the low air-pressure high airflow event is represented by a maximum acceptable value. [0044] Where a PAPR blower control system uses constant voltage or constant current control, the method of providing an alarm if the operating condition reaches a low air-pressure high airflow event is similar to the above. The difference is that often the motor voltage or motor current is fixed by the electronic control unit after the initial start-up and substantially maintained during use. Hence step 31 of adjusting the motor voltage is often not employed in such systems, but the remaining method steps described above are carried out to determine if an alarm should be activated. Although in the above embodiment a uniform volumetric airflow system is described, a uniform mass airflow system may be used, where a substantially constant mass of air is delivered to the user rather than a substantially constant volume of air.
A method of controlling a powered air purifying respirator blower system to detect a low air pressure high airflow event is disclosed. The blower system comprises a fan powered by an electric motor, controlled by an electronic control unit for delivering a forced flow of filtered air to a user. The electronic control unit has a plurality of data points representing events defining an acceptable operating range in terms of different characteristics of the blower system stored therein. The method comprises sampling a characteristic that represents the operating condition of the blower to obtain a sampled data point; comparing the sampled data point and the stored data point representing a low air-pressure high airflow event, for the same characteristic; repeating the sampling during a fixed time period, and if the comparing step indicates the low air-pressure high airflow event has been reached for the majority of the time period; activating an alarm. Use of a respirator employing the method to deliver a forced flow of filtered air to a contained user environment is also disclosed.
Summarize the key points of the given document.
[ "[0001] The present invention relates to a method of controlling a blower system, for use in a powered air purifying respirator (PAPR), in particular, to detect a low air-pressure high airflow event.", "BACKGROUND [0002] When working in areas where there is known to be, or there is a risk of there being, dusts, fumes or gases that are potentially hazardous or harmful to health, it is usual for the worker to use a respirator.", "A common type of respirator used in such circumstances is a powered air purifying respirator (PAPR).", "A PAPR has a blower system comprising a fan powered by an electric motor for delivering a forced flow of air to the respirator user.", "A turbo unit usually includes a housing that typically contains the blower system, and is adapted to connect a filter to the blower system.", "[0003] Air is drawn through the filter by the blower system and passed from the turbo unit through a breathing tube to one of a mask, or a contained user environment, such as mask, helmet, hood or suit (where the user is contained within an environment separated from ambient and external conditions) thus providing filtered air to the user's breathing zone (the area around their nose and mouth).", "A blower system for a PAPR may also include an electronic control unit to regulate the power driving the fan.", "Typically, a single power supply, for example a battery, provides power for both the fan and the electronic control unit.", "[0004] Sufficient airflow is required by the user to ensure that the designated level of respiratory protection is maintained.", "For example, too low an airflow can cause ingress of contaminants into the user's breathing zone.", "In response to this, the electronic control unit may be used to trigger alarms to the user, for example, to alert the user if the airflow falls below a designated level, or to alert the user that the filters may be blocked with dust and need to be replaced.", "It is also common for the electronic control unit to trigger an alarm if the battery is depleted to a level where the correct operation of the PAPR is likely to be compromised.", "[0005] It is desirable that the user of a PAPR can be alerted if an event occurs that takes the operation of the PAPR outside of the defined operation range.", "This is particularly desirable now that PAPR suit systems are available.", "If the integrity of a suit is compromised it can often go unnoticed by the user.", "SUMMARY [0006] The present invention provides a method of controlling a powered air purifying respirator blower system to detect a low air-pressure high airflow event, the system comprising a fan powered by an electric motor, controlled by an electronic control unit for delivering a forced flow of filtered air to a user, and the electronic control unit having a plurality of data points representing events defining an acceptable operating range in terms of different characteristics of the blower system stored therein, the method comprising: sampling a characteristic that represents the operating condition of the blower to obtain a sampled data point;", "comparing the sampled data point and the stored data point representing a low air-pressure high airflow event, for the same characteristic;", "repeating the sampling during a fixed time period, and if the comparing step indicates the low air-pressure high airflow event has been reached for the majority of the time period;", "activating an alarm.", "[0007] By taking into consideration deviations of the operating condition from the blower system operating range, for example an increase in airflow and/or a decrease in blower system air pressure, the user can be alerted to the situation where the PAPR system has been compromised to allow them to take appropriate action.", "[0008] Other features of the invention will be apparent from the attached dependent claims.", "[0009] The present invention provides a method of controlling a powered air purifying respirator blower system where the sampling is carried out by the electronic control unit.", "[0010] Preferably, the characteristic sampled is one of: voltage across the motor;", "current through the motor;", "speed of the motor;", "or any combination thereof.", "In this situation the low air-pressure high airflow event is a minimum acceptable value for the characteristic sampled.", "[0011] The present invention further provides a method of controlling a powered air purifying respirator blower system where the sampling is carried out using a sensor external to the electronic control unit.", "[0012] The present invention yet further provides a method of controlling a powered air purifying respirator blower system where the characteristic sampled is one of air-pressure or airflow.", "In the situation where the characteristic is air-pressure, the low air-pressure high airflow event is a minimum acceptable value.", "Alternatively, in the situation where the characteristic is airflow, the low air-pressure high airflow event is a maximum acceptable value.", "[0013] The alarm is at least one or more of an audible alarm, a visible alarm, or a vibration alarm.", "[0014] Preferably, the fixed time period is in the range of 3 to 30 seconds.", "Preferably, the respirator delivers a substantially uniform volumetric airflow to a user.", "[0015] Preferably, the respirator operates at one of: a substantially constant current and a substantially constant voltage.", "[0016] The present invention also provides for the use of a respirator employing a method of controlling a powered air purifying respirator blower system, to deliver a forced flow of filtered air as described above to contained user environment.", "Preferably, the contained user environment is one of a mask, a helmet or a hood.", "Alternatively the contained user environment is a suit.", "BRIEF DESCRIPTION OF THE DRAWINGS [0017] By way of example only, an embodiment of the invention will now described below with reference to the accompanying drawings, in which: [0018] FIG. 1 a is a diagrammatical graph of a constant current operating range;", "[0019] FIG. 1 b is a diagrammatical graph of a uniform volumetric airflow operating range;", "[0020] FIG. 2 is a diagrammatical illustration of a powered air purifying respirator;", "[0021] FIG. 3 shows a block diagram of a blower system for the air purifying respirator of FIG. 3 ;", "and [0022] FIG. 4 shows a flow diagram of a blower control sequence according an embodiment of the present invention.", "DETAILED DESCRIPTION [0023] Many electronic control units deliver either a constant current or a constant voltage to the electric motor so that the airflow from the blower system is not affected as the battery is depleted during operation of the PAPR.", "Some electronic control units control the power to the electric motor with the aim of maintaining a substantially uniform volumetric airflow from the blower system.", "[0024] Such electronic control units often compensate for both changes in battery voltage and also compensate for changes in the filter pressure drop as the filter clogs with dust or particles.", "The term “volumetric airflow”", "indicates the volume of air provided to a user at any one time as opposed to the mass of air provided to a user any one time.", "[0025] The three types of control systems: constant current;", "constant voltage;", "and volumetric airflow, operate using parameters set within defined operating ranges for each of the electrical characteristics of the motor (voltage across the motor, current through the motor and motor power, speed of the motor), as well as for the air-pressure and airflow produced by the motor.", "FIG. 1 a is a diagrammatical graph of a constant current operating range and FIG. 1 b is a diagrammatical graph of a uniform volumetric airflow operating range.", "The exemplary constant current controlled blower system operating range is similar to that of a constant voltage operating range.", "The graph of FIG. 1 a shows that the airflow from the blower system increases as the air-pressure drop across the blower system decreases.", "The section of the graph marked A represents insufficient airflow to maintain the desired level of respiratory protection.", "This is the high air-pressure low airflow operating range.", "The section of the graph between points B and C is the desired operating range where sufficient airflow is delivered to the user to maintain suitable respirator protection.", "The airflow from a constant current or constant voltage blower system is likely to reduce over time as the pressure drop of the filter connected to the blower increases due to clogging with dust or particles.", "However, the operating range during the lifetime of the blower will be broadly consistent with the operating range shown.", "B represents the high air-pressure low airflow event where a low airflow alarm would be triggered.", "C represents the low air-pressure high airflow event, above which, it is likely that the integrity of the PAPR has been compromised, marked as region D on the graph.", "The characteristic curve of FIG. 1 b has a flat section between points B and C where the desired operating airflow is uniform and sufficient to maintain suitable respirator protection.", "The section of the graph marked A representing insufficient airflow to maintain the desired level of respiratory protection is the high air-pressure low airflow operating range.", "Similar to FIG. 1 a , point C of FIG. 1 b represents the low air-pressure high airflow event, above which, in the region marked D, it is likely that the integrity of the PAPR has been compromised.", "[0026] If an event occurs that causes the airflow to be reduced or the air-pressure across the blower system to increase (a high air-pressure low airflow event), it is likely that a low airflow alarm will be triggered to alert the user to the fact that they are not receiving sufficient filtered air and that ingress of potentially contaminated air into their breathing zone is likely.", "However, there is no provision for the triggering of an alarm when an event occurs that causes the air-pressure to drop or the airflow to rise (a low air-pressure high airflow event).", "[0027] The following are some examples of problems that can arise that are unlikely to trigger an alarm in current PAPR systems.", "Each of these represents a low air-pressure high airflow event.", "A failure in the filtering process of a PAPR, such as the filter media being inadvertently damaged or punctured can result in potentially contaminated air to ingress the user's breathing zone.", "Furthermore, breaches of system integrity such as a filter not being fitted properly, a filter being fitted without a gasket or seal, or a filter becoming removed or partially removed during use may give rise to similar events.", "If the breathing tube is incorrectly fitted to the mask, helmet, hood or suit, or to the turbo outlet, or becomes disconnected or damaged during use similar events are likely to occur.", "Likewise, if a local contained user environment, such as a mask, helmet, hood or suit to which the PAPR is attached is torn or damaged or otherwise compromised, a situation where potentially contaminated air may ingress the users breathing zone may occur.", "In addition, if any mask, helmet, hood or suit is removed during use and the PAPR turbo is left running, current commercially available PAPRs do not trigger an alarm.", "[0028] The present invention is based on the realization that currently known methods of controlling a blower system currently employed in PAPRs do not trigger an alarm when the PAPRs integrity is compromised as described above.", "Furthermore, it has been realised that the above described problems result in the blower system developing a high airflow low air-pressure event and as such the blower system parameters can be used to provide the electronic control unit with information about the environment that the blower system is operating within and more particularly information about a contained user environment, such as a mask (for example, a full face respirator mask, a half face respirator mask, and so on.), helmet, hood or suit that the blower system is supplying.", "Such an event may also sometimes be referred to as indicating a breach in the integrity of the contained user environment.", "[0029] One exemplary embodiment of the present invention described below employs a turbo as shown in FIG. 2 .", "FIG. 2 is a diagrammatical illustration of a powered air purifying respirator.", "The air purifying respirator shown is a volumetric airflow device, but the components would be similar, and sometimes, substantially identical for both the constant voltage and constant current devices mentioned above.", "The exemplary PAPR comprises a head or a face piece, such as a hood 1 , a turbo unit 2 , a breathing tube 3 , a filter 4 and turbo support, such as a belt 5 .", "The hood 1 is worn on the user's 6 head.", "It at least partially encloses the user's 6 head to form a breathing zone 7 , that is, the area around their nose and mouth, so that the filtered air is directed to this breathing zone 7 .", "The turbo unit 2 may be attached to a belt 5 to enable it to be secured about the user's torso.", "The turbo unit 2 usually includes a housing (not shown) that houses a blower system (not shown), which draws the air through the PAPR system using a fan (also not shown).", "The turbo unit 2 supplies air to the hood 1 through the breathing tube 3 which is connected between the outlet 8 of the turbo unit 2 and the inlet 9 of the hood 1 .", "The turbo unit 2 is fitted with a filter 4 , which can be either inside the turbo unit or attached to the turbo unit as shown in FIG. 2 such that the filter 4 is in the airflow path, preferably disposed upstream of a fan opening of the blower.", "The purpose of providing the filter 4 is to remove at least a certain amount of particles and/or gases and/or vapours from the ambient air before the air is delivered to the user 6 .", "The battery pack 10 , which is fitted to the turbo unit 2 provides power to the electronic control unit 18 and to the motor 17 (both shown in FIG. 2 as discussed below).", "[0030] Although a hood is illustrated in FIG. 2 , the hood 1 could substituted by another head piece or face piece, such as a mask, a helmet or a full suit, provided that a closed user environment, covering at least the original area of the user's face, to direct air to the user's breathing zone 7 , is created.", "[0031] The following illustrates how the blower system for an air purifying respirator may function.", "In the following examples, the structural components of the PAPR may be assumed to be as described above with reference to FIGS. 2 and 3 .", "[0032] FIG. 3 shows a block diagram of a blower system for the air-purifying respirator of FIG. 2 .", "This blower system is housed within the turbo unit 2 illustrated in FIG. 2 .", "In accordance with this embodiment of the invention the blower 11 includes a housing 12 having an inlet 13 and an outlet 14 .", "The blower 11 further includes a fan 15 , having a plurality of blades 16 , driven by a motor 17 .", "The blower 11 is controlled by an electronic control unit 18 which regulates the power provided to the motor 17 .", "[0033] With further reference to FIG. 3 , the blower system comprises an electronic control unit 18 that functions to maintain a substantially uniform, preferably constant, volumetric airflow to the hood 1 .", "The electronic control unit 18 comprises: a microprocessor device 19 , such as a single chip microcontroller, for computing information;", "a memory device 20 , such as flash RAM, for storing information, for example, calibration data and sensor input receivers 21 a , 21 b , 21 c , for receiving data from sensors such as sensors to detect the voltage across the motor, sensors to detect current through the motor and sensors to detect the speed of the motor.", "Also included is an output controller 22 , such as a pulse width modulation controller chip, for providing power to the motor 17 and any alarm or status indicators, such as buzzers or light emitting diodes that may be included in the PAPR.", "The memory device 20 of the electronic control unit 18 has two parts: a fixed memory and a temporary memory.", "The fixed memory is populated with data, for example, at the time of manufacture, comprising the algorithms and programs for enabling the microprocessor 19 to carry out its calculations and procedures, and calibration information from the factory calibration procedure.", "The temporary memory is used for storing data and information such as sensor readings and fan and motor operating parameter data collected during start-up and running of the turbo unit 2 .", "If desired, this data maybe erased when the turbo unit 2 is powered down.", "[0034] In this embodiment of the present invention speed of the motor and motor voltage are the characteristics chosen to determine the operating condition of the blower system.", "The speed of the motor may be measured by means of a sensor 23 that is connected to the blower 11 and measures the number of revolutions of the fan 15 in a given time period.", "A suitable type of sensor for measuring the speed of the motor would be a Hall Effect device, although other types of sensor, for example optical sensors, could be used.", "The speed of the motor information is received by the microprocessor device 19 of the electronic control unit 18 .", "The applied voltage 22 to the electric motor 17 may be monitored directly by an input 21 to the microprocessor 19 of the electronic control unit 18 .", "This means that, in this exemplary embodiment, two of the sensor inputs 21 b , 21 c provided are inactive during this particular method of use, but may be activated if alternative characteristics are chosen.", "[0035] During the factory setup and calibration of the exemplary blower system, of FIG. 3 , a plurality of data points, including those relating to the operating characteristics described above, (speed of the motor and voltage across the motor), representing events defining an acceptable operating range of the blower 11 may be stored in the fixed memory 20 of the electronic control unit 18 .", "The stored data points may include data points that represent a low air-pressure high airflow (LPHF) event at the limit of the acceptable operating range (see FIG. 1 b ).", "[0036] When the blower 11 is started up and during use, the electronic control unit 18 endeavours to maintain a substantially uniform volumetric airflow.", "The required volumetric airflow may be predetermined during the factory setup.", "For example the volumetric airflow is preferably in the range of, but not limited to 70 to 250 litres/minute and is dependent on the level of respiratory protection required by the PAPR and the type of mask, helmet, hood or suit used by the PAPR.", "[0037] More preferably the volumetric airflow is in the range 120 to 220 litres/minute, yet more preferably in the range 160 to 200 litres/minute.", "During use of the blower 11 the electronic control unit 18 samples data points for the blower system operating characteristics and compares them with the stored data points.", "If certain predetermined criteria are met the electronic control unit 18 will trigger an alarm 24 to be activated to warn the user that an unacceptable event has occurred.", "[0038] FIG. 4 shows a flow diagram of a blower system control sequence according to an embodiment of the present invention.", "In this exemplary embodiment, when the turbo unit 2 is started up, an algorithm stored in the fixed memory 20 of the electronic control unit 18 begins the sampling sequence at step 26 .", "[0039] The sequence of FIG. 4 is repeated, usually a plurality of times, by the electronic control unit 18 at regular intervals predetermined by the algorithm stored in the fixed memory 20 .", "For example the interval between consecutive samples is in the range of, but not limited to 2 to 50 ms, more preferably in the range 2 to 20 ms, yet more preferably in the range 2 to 10 ms.", "A rolling average algorithm is often used in such systems, wherein a plurality of samples are collected and average to reduce the effect of electrical noise in the system.", "In this embodiment of the present invention a rolling average of 60 samples is used.", "Each sampled data point is processed as follows.", "[0040] At step 27 the speed of the motor is measured by the electronic control unit 18 by means of the sensor 23 in the blower 11 and stored in the temporary memory 20 .", "From the stored speed of the motor data point the electronic control unit 18 calculates the expected motor voltage, at step 28 , for that particular speed of the motor 17 by referring to the stored data points stored in the fixed memory 20 from the calibration of the blower system, and stores the result in the temporary memory 20 .", "At step 29 the electronic control unit 18 compares the data point in the temporary memory 20 for the expected motor voltage and the motor voltage data points stored in the fixed memory that represent a low air-pressure high airflow (LPHF) event.", "If the expected motor voltage is higher than the event motor voltage, the electronic control unit proceeds to follow a sequence of steps 30 to check and maintain a substantially uniform airflow and to check for other blower system events.", "If, however, the expected motor voltage is lower than the event motor voltage, the electronic control unit adjusts the actual motor voltage at step 31 (for example, by means of a pulse width modulation controller) to be equal to the high airflow event motor voltage and starts a high airflow timer, step 32 .", "The sequence is repeated at regular intervals, as described above.", "After subsequent data points are sampled, the high airflow timer may either be cancelled or remain active, as appropriate at step 33 .", "If the timer remains active for a fixed time period at step 34 , indicating that the low air-pressure high airflow (LPHF) condition has been present for the majority of that period, the electronic control unit 18 will trigger to activate an alarm 24 at step 35 to the user.", "The fixed time period is in the range of, but not limited to 3 to 30 seconds, more preferably in the range 5 to 15 seconds, yet more preferably in the range 8 to 12 seconds.", "If further data points outside of this time range are sampled and the low air-pressure high airflow (LPHF) event is no longer detected, the alarm is cancelled.", "Alternatively the alarm may be manually cancelled by the user, for example by turning the PAPR off.", "[0041] The low air-pressure high airflow alarm 24 according to an embodiment of the present invention may comprise a visual alarm, an audible alarm, a vibration alarm or any combination thereof.", "The visual alarm is preferably given by means of a light, such as a light emitting diode (LED) or a bulb, that is visible external to the turbo unit.", "However, the visual alarm may be an alternative type indicator, for example: a warning message;", "a numeric display or a liquid crystal display (LCD), or another suitable device.", "The visual alarm may be continuous, intermittent, or display information or coded information to the user.", "For example, if the visual alarm comprises a light, the light may be flashed intermittently to attract the attention of the user.", "The audible alarm is preferably given by a piezoelectric device, although alternative types of sounders or buzzers may be used, for example, electro-mechanical buzzers.", "The audible alarm may be continuous or intermittent, or may be variable in volume and/or in the frequency of the sound produced.", "For certain applications, such as noisy environments where it may be difficult for the user to hear an audible alarm, it may be desirable to use a vibration alarm such as those commonly found in mobile phones.", "The vibration alarm may be set to vibrate continuously or intermittently.", "Each type of alarm may be used alone or in combination with one or more other types of alarm.", "For example, it may be desirable to operate an intermittent visual alarm and an intermittent audible alarm simultaneously, ensuring that the flashing of the visual alarm occurs contemporaneously with the sounding of the audible alarm.", "Another exemplary combination may be the use of an audible and a vibration alarm simultaneously.", "[0042] In the above embodiment, the motor characteristics of speed of the motor and voltage across the motor are used to determine a low air-pressure high airflow event, and measured directly using sensors external to the motor.", "Alternatively, other characteristics of the blower system representing the operating condition may be used.", "These may be any electrical characteristics of the blower 11 , giving an indirect measurement of air-pressure and airflow, measured by the electronic control unit 18 or an additional sensor 25 , for example, current through the motor or motor power.", "However, the physical characteristics of air-pressure or airflow may be measured directly, using sensors 25 , which may be disposed external to the motor 17 .", "For example, the air-pressure could be measured by a pressure sensor adapted to compare the pressure between the inlet 13 and the outlet 14 of the blower 11 , or airflow could be measured by an airflow sensor positioned in the airflow path at the outlet 14 of the blower 11 .", "Preferably therefore the characteristic sampled is one of: voltage across the motor;", "current through the motor;", "speed of the motor;", "or any combination thereof.", "Alternatively the characteristics sampled may be one of air-pressure or airflow.", "[0043] If the characteristic sampled is one of voltage across the motor 17 ;", "current through the motor;", "motor power or speed of the motor, it is likely that the low air-pressure high airflow event is represented by a minimum acceptable value.", "If the characteristic sampled is air-pressure, then the low air-pressure high airflow event is also represented by a minimum acceptable value.", "However, if the motor characteristic sampled is airflow, then the low air-pressure high airflow event is represented by a maximum acceptable value.", "[0044] Where a PAPR blower control system uses constant voltage or constant current control, the method of providing an alarm if the operating condition reaches a low air-pressure high airflow event is similar to the above.", "The difference is that often the motor voltage or motor current is fixed by the electronic control unit after the initial start-up and substantially maintained during use.", "Hence step 31 of adjusting the motor voltage is often not employed in such systems, but the remaining method steps described above are carried out to determine if an alarm should be activated.", "Although in the above embodiment a uniform volumetric airflow system is described, a uniform mass airflow system may be used, where a substantially constant mass of air is delivered to the user rather than a substantially constant volume of air." ]
CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority to U.S. Provisional Application Ser. No. 61/807,458, filed Apr. 2, 2013, entitled CLOTH DIAPER. BACKGROUND [0002] The present invention relates to cloth diapers. Cloth diaper manufacturers have designed diapers that have an absorbent insert that is attached to both the reside front and back of the diaper, wherein excess fabric may be folded to accommodate male or female. Other cloth diapers have an absorbent insert that is attached with some form of fastener at either the front or back of the diaper, which allows the user to add additional absorbency to the diaper. In some diapers, the snap in and separable insert is the only absorbent member in the diaper. The additional inserts may be removed during laundering to aid in the washing and drying. Another variation is a cloth diaper with so absorbent insert which is sewn into the inside of the diaper on three sides, forming a pocket, and including an extending tail which is folded into the pocket for use. [0003] Size adjustable diapers are available, in which the length of the diaper from the front edge to the back edge can be adjusted, by providing two or three rows of like fasteners spaced from at least one row of mating fasteners. By folding a portion of the length of the diaper on itself, and snapping mating fasteners together to hold the fold, the size of the diaper is adjusted. SUMMARY OF THE INVENTION [0004] In the present invention, a cloth diaper includes a size adjustable impermeable outer layer, and an elongated absorbent insert permanently attached only at one end to the inside of said outer layer, near the upper edge of the outer layer. The absorbent insert extends a substantial distance beyond the opposite upper edge of said outer layer. Preferably, there is an absorbent layer attached to the outer layer, between the outer layer and the insert. BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is a front view of a preferred embodiment adjustable diaper at its largest size; [0006] FIG. 2 is a plan view of the interior side of the diaper of FIG. 1 opened flat, arranged with its back portion at the top of figure, its front portion at the bottom of the figure, and the absorbent insert fully extending; [0007] FIG. 3 is a plan view of the interior side of the diaper, showing the absorbent insert folded over once; [0008] FIG. 4 is a plan view of the interior side of the diaper, showing the absorbent insert folded over twice at middle of the diaper, which will be the bottom of the diaper as worn; [0009] FIG. 5 is a plan view of the interior side of the diaper, showing the absorbent insert folded over twice toward the front of the diaper; [0010] FIG. 6 is a front view of the diaper adjusted to a smaller size. [0011] FIG. 7 is plan view of the interior of the adjusted smaller diaper of FIG. 6 opened flat, with the absorbent insert folded over twice to accommodate the smaller size of the diaper; and [0012] FIG. 8 is a front view of the adjusted smaller diaper as it will look when worn. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] The preferred embodiment diaper 1 shown in the drawings has a water proof outer layer 10 , to which is attached to absorbent layer 20 , which comprises of one or more layers of an absorbent material ( FIGS. 1 and 2 ). The term “layer” as used herein includes an integrated layer which may itself be made up of two or several layers of fabric. Inner absorbent layer 20 is dimensioned to encompass the area of the “wet zone” of the diaper. As is well known to every parent, the wet zone ordinarily extends from near the front or back upper edge of the diaper to near the opposite upper edge. At one end of interior of the diaper, specifically at an end of the wet zone, an absorbent insert 30 is permanently attached to the water proof outer layer. As shown, insert 30 is attached to at the top of the wet zone, which will be the top of the rear of the wet zone when the diaper is worn. [0014] Absorbent insert 30 exceeds the length of the diaper by a substantial distance, and may be folded to meet baby's needs. The term substantial distance means the absorbent insert when folded over once when when the diaper is adjusted to its largest size, provides two layers of added absorbency over the wet zone of the diaper. Preferably, absorbent insert 30 is about twice the length of the wet zone of the diaper, when the diaper is adjusted to its largest size, and most preferably at least twice the length of the wet zone. As can be seen from the drawings, absorbent insert is made of material such that either side of absorbent insert 30 can be placed against the baby's skin. [0015] Outer layer 10 is made of a water impervious material. It is sewn to absorbent layer 20 , which is comprised of one or more layers 20 of absorbent material. The waterproof layer 10 extends down the back, bottom and front sides 12 , 13 and 14 respectively, of the diaper to prevent wicking of moisture out of absorbent layer 20 , and absorbent insert 30 . Elastic is encased around the top edge 11 of the back or rear portion 12 of the diaper ( FIG. 2 ) to help prevent “blow-outs”. Elastic is sewn to the inner seam around both curvilinear edges of the center or bottom portions 13 of the diaper 1 . [0016] There are waterproof tabs 15 that extend out from the upper back portion 12 of the diaper and wrap around the front 14 of the diaper, using fasters 16 A to securely fasten to mating fasteners 16 B at the front 14 of the diaper, thereby securing the diaper around the waist of the wearer. In the preferred embodiments, fasteners 16 A and 16 B are mating male and female snaps. There are two horizontal rows of eight mating snaps 16 B each, on the front 14 of outer cover 10 . The two rows of snaps 16 B are spaced to correspond to the spacing of snaps 16 A on each of tabs 15 . As shown, snaps 16 A are female snaps, and snaps 16 B are male snaps. Snaps multiple snaps 16 B served as waist adjustment snaps, in that the diaper tabs 15 can be fastened to different pairs of snaps 16 B, in order to accommodate varying baby waist sizes. In this way, diaper 10 can be used for babies of many different sizes, and indeed can be dimensioned to fit substantially all sizes. By comparing FIG. 8 to FIG. 1 , one can see that in FIG. 8 , the female snaps 16 A on tabs 15 have been secured to the third pair of male snaps 16 B in from each edge, leaving only two pair of the male snaps 16 B visible in FIG. 8 . [0017] Inner absorbent layer or layers 20 are preferably sewn to outer layer 10 . Absorbent insert 30 is preferably comprised of multiple layers of absorbent fabric and is attached only along an end edge 31 to the back portion 12 of diaper 1 , where the outer waterproof layer and the inner absorbent fabric layer 20 meet. [0018] The rise of the diaper is adjusted by using mating rise adjustment fasteners 17 A and 17 B that are reinforced and located across the front 14 of outer waterproof layer 10 ( FIG. 1 ). In the preferred embodiment, fasteners 17 A and 17 B are snaps. There is one row of three male snaps 17 B toward the upper portion of front 14 , just below the bottom row of eight male snaps which are available for mating with the bottom female snap 17 A on tabs 15 . There are three rows of three each female snaps 17 A, each spaced progressively further below the upper row of three male snaps 17 B. By folding front 14 upon itself, and fastening one of the three rows of female snaps 17 A to the upper row of three male snaps 17 B, diaper 1 can be adjusted to three different sizes, in terms of the “rise.” By comparing FIG. 1 to FIG. 6 , one can see that the bottom row of female snaps 17 A has been secured to the row of three male snaps 16 B, thereby shortening the rise of diaper 1 to its shortest position. One can adjust the rise to two intermediate positions by using either of the other two rows of three female snaps 17 A. [0019] The long “tongue-like” permanently attached absorbent insert 30 allows for all the absorbency that is necessary, while providing optimal exposure to water and air during the laundering process. Since only one end of the insert is connected to the interior of the diaper, there is less bulk on smaller babies and the preferred amount of absorbency where necessary for male and/or female. [0020] In use, diaper 1 should be laid out flat and the attached insert 30 folded with more fabric in the middle for females ( FIG. 4 ), more in the front for males ( FIG. 5 ), or distributed evenly inside the diaper ( FIG. 3 ). The front rise snaps 17 A and 17 B should be fastened so that the front of the diaper is close in proximity to the wearer's navel. When set to one of the smaller rise settings ( FIG. 6 ), it will be advantageous for the insert to be folded with more fabric towards the middle or back of the diaper to reduce bulkiness ( FIG. 7 ). Once the insert is positioned and the rise appropriately set, one lays the baby on the diaper and fastens tabs 15 to the front snaps 16 B so as to hold the diaper securely around the baby's waist. [0021] The present diaper provides a one-size, all-in-one diaper that washes cleaner and dries faster than other one-size, all-in-one diapers on the market. Most one-size, all-in-one diapers use too many layers of fabric, in too close of proximity with each other. Such diapers take multiple drier cycles to completely dry, and generally result in stinky, damp diapers. The present diaper is easy to use, and allows the absorbency to be adjusted to accommodate the needs of both male and female. [0022] Finally, the present diaper is trimmer than other one-size, all-in-one diapers without eliminating of absorbency. Even in its largest size, permanently attached insert 30 provides two additional layers of absorbency, in addition to absorbent layer 20 . In FIGS. 4 and 5 , three additional layers of absorbency are provided in critical locations. In the diaper as adjusted to its smallest size, three additional layers of absorbency are provided. Thus for most applications one has at least four layers of absorbency, at least in the critical locations. Yet in the washing and drying cycle, there is realty only one layer of absorbency being washed and dried. [0023] Of course, it is understood that the foregoing describes preferred embodiments of the invention, and that changes and alterations can be made without departing from the spirit and scope of the invention as set forth in the appended claims.
A cloth diaper includes a size adjustable impermeable outer layer, and an elongated absorbent insert permanently attached only at one end to the inside of said outer layer, near the upper edge of the outer layer. The absorbent insert extends a substantial distance beyond the opposite upper edge of said outer layer. Preferably, there is an absorbent layer attached to the outer layer, between the outer layer and the insert.
Provide a concise summary of the essential information conveyed in the given context.
[ "CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority to U.S. Provisional Application Ser.", "No. 61/807,458, filed Apr. 2, 2013, entitled CLOTH DIAPER.", "BACKGROUND [0002] The present invention relates to cloth diapers.", "Cloth diaper manufacturers have designed diapers that have an absorbent insert that is attached to both the reside front and back of the diaper, wherein excess fabric may be folded to accommodate male or female.", "Other cloth diapers have an absorbent insert that is attached with some form of fastener at either the front or back of the diaper, which allows the user to add additional absorbency to the diaper.", "In some diapers, the snap in and separable insert is the only absorbent member in the diaper.", "The additional inserts may be removed during laundering to aid in the washing and drying.", "Another variation is a cloth diaper with so absorbent insert which is sewn into the inside of the diaper on three sides, forming a pocket, and including an extending tail which is folded into the pocket for use.", "[0003] Size adjustable diapers are available, in which the length of the diaper from the front edge to the back edge can be adjusted, by providing two or three rows of like fasteners spaced from at least one row of mating fasteners.", "By folding a portion of the length of the diaper on itself, and snapping mating fasteners together to hold the fold, the size of the diaper is adjusted.", "SUMMARY OF THE INVENTION [0004] In the present invention, a cloth diaper includes a size adjustable impermeable outer layer, and an elongated absorbent insert permanently attached only at one end to the inside of said outer layer, near the upper edge of the outer layer.", "The absorbent insert extends a substantial distance beyond the opposite upper edge of said outer layer.", "Preferably, there is an absorbent layer attached to the outer layer, between the outer layer and the insert.", "BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is a front view of a preferred embodiment adjustable diaper at its largest size;", "[0006] FIG. 2 is a plan view of the interior side of the diaper of FIG. 1 opened flat, arranged with its back portion at the top of figure, its front portion at the bottom of the figure, and the absorbent insert fully extending;", "[0007] FIG. 3 is a plan view of the interior side of the diaper, showing the absorbent insert folded over once;", "[0008] FIG. 4 is a plan view of the interior side of the diaper, showing the absorbent insert folded over twice at middle of the diaper, which will be the bottom of the diaper as worn;", "[0009] FIG. 5 is a plan view of the interior side of the diaper, showing the absorbent insert folded over twice toward the front of the diaper;", "[0010] FIG. 6 is a front view of the diaper adjusted to a smaller size.", "[0011] FIG. 7 is plan view of the interior of the adjusted smaller diaper of FIG. 6 opened flat, with the absorbent insert folded over twice to accommodate the smaller size of the diaper;", "and [0012] FIG. 8 is a front view of the adjusted smaller diaper as it will look when worn.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS [0013] The preferred embodiment diaper 1 shown in the drawings has a water proof outer layer 10 , to which is attached to absorbent layer 20 , which comprises of one or more layers of an absorbent material ( FIGS. 1 and 2 ).", "The term “layer”", "as used herein includes an integrated layer which may itself be made up of two or several layers of fabric.", "Inner absorbent layer 20 is dimensioned to encompass the area of the “wet zone”", "of the diaper.", "As is well known to every parent, the wet zone ordinarily extends from near the front or back upper edge of the diaper to near the opposite upper edge.", "At one end of interior of the diaper, specifically at an end of the wet zone, an absorbent insert 30 is permanently attached to the water proof outer layer.", "As shown, insert 30 is attached to at the top of the wet zone, which will be the top of the rear of the wet zone when the diaper is worn.", "[0014] Absorbent insert 30 exceeds the length of the diaper by a substantial distance, and may be folded to meet baby's needs.", "The term substantial distance means the absorbent insert when folded over once when when the diaper is adjusted to its largest size, provides two layers of added absorbency over the wet zone of the diaper.", "Preferably, absorbent insert 30 is about twice the length of the wet zone of the diaper, when the diaper is adjusted to its largest size, and most preferably at least twice the length of the wet zone.", "As can be seen from the drawings, absorbent insert is made of material such that either side of absorbent insert 30 can be placed against the baby's skin.", "[0015] Outer layer 10 is made of a water impervious material.", "It is sewn to absorbent layer 20 , which is comprised of one or more layers 20 of absorbent material.", "The waterproof layer 10 extends down the back, bottom and front sides 12 , 13 and 14 respectively, of the diaper to prevent wicking of moisture out of absorbent layer 20 , and absorbent insert 30 .", "Elastic is encased around the top edge 11 of the back or rear portion 12 of the diaper ( FIG. 2 ) to help prevent “blow-outs.”", "Elastic is sewn to the inner seam around both curvilinear edges of the center or bottom portions 13 of the diaper 1 .", "[0016] There are waterproof tabs 15 that extend out from the upper back portion 12 of the diaper and wrap around the front 14 of the diaper, using fasters 16 A to securely fasten to mating fasteners 16 B at the front 14 of the diaper, thereby securing the diaper around the waist of the wearer.", "In the preferred embodiments, fasteners 16 A and 16 B are mating male and female snaps.", "There are two horizontal rows of eight mating snaps 16 B each, on the front 14 of outer cover 10 .", "The two rows of snaps 16 B are spaced to correspond to the spacing of snaps 16 A on each of tabs 15 .", "As shown, snaps 16 A are female snaps, and snaps 16 B are male snaps.", "Snaps multiple snaps 16 B served as waist adjustment snaps, in that the diaper tabs 15 can be fastened to different pairs of snaps 16 B, in order to accommodate varying baby waist sizes.", "In this way, diaper 10 can be used for babies of many different sizes, and indeed can be dimensioned to fit substantially all sizes.", "By comparing FIG. 8 to FIG. 1 , one can see that in FIG. 8 , the female snaps 16 A on tabs 15 have been secured to the third pair of male snaps 16 B in from each edge, leaving only two pair of the male snaps 16 B visible in FIG. 8 .", "[0017] Inner absorbent layer or layers 20 are preferably sewn to outer layer 10 .", "Absorbent insert 30 is preferably comprised of multiple layers of absorbent fabric and is attached only along an end edge 31 to the back portion 12 of diaper 1 , where the outer waterproof layer and the inner absorbent fabric layer 20 meet.", "[0018] The rise of the diaper is adjusted by using mating rise adjustment fasteners 17 A and 17 B that are reinforced and located across the front 14 of outer waterproof layer 10 ( FIG. 1 ).", "In the preferred embodiment, fasteners 17 A and 17 B are snaps.", "There is one row of three male snaps 17 B toward the upper portion of front 14 , just below the bottom row of eight male snaps which are available for mating with the bottom female snap 17 A on tabs 15 .", "There are three rows of three each female snaps 17 A, each spaced progressively further below the upper row of three male snaps 17 B. By folding front 14 upon itself, and fastening one of the three rows of female snaps 17 A to the upper row of three male snaps 17 B, diaper 1 can be adjusted to three different sizes, in terms of the “rise.”", "By comparing FIG. 1 to FIG. 6 , one can see that the bottom row of female snaps 17 A has been secured to the row of three male snaps 16 B, thereby shortening the rise of diaper 1 to its shortest position.", "One can adjust the rise to two intermediate positions by using either of the other two rows of three female snaps 17 A. [0019] The long “tongue-like”", "permanently attached absorbent insert 30 allows for all the absorbency that is necessary, while providing optimal exposure to water and air during the laundering process.", "Since only one end of the insert is connected to the interior of the diaper, there is less bulk on smaller babies and the preferred amount of absorbency where necessary for male and/or female.", "[0020] In use, diaper 1 should be laid out flat and the attached insert 30 folded with more fabric in the middle for females ( FIG. 4 ), more in the front for males ( FIG. 5 ), or distributed evenly inside the diaper ( FIG. 3 ).", "The front rise snaps 17 A and 17 B should be fastened so that the front of the diaper is close in proximity to the wearer's navel.", "When set to one of the smaller rise settings ( FIG. 6 ), it will be advantageous for the insert to be folded with more fabric towards the middle or back of the diaper to reduce bulkiness ( FIG. 7 ).", "Once the insert is positioned and the rise appropriately set, one lays the baby on the diaper and fastens tabs 15 to the front snaps 16 B so as to hold the diaper securely around the baby's waist.", "[0021] The present diaper provides a one-size, all-in-one diaper that washes cleaner and dries faster than other one-size, all-in-one diapers on the market.", "Most one-size, all-in-one diapers use too many layers of fabric, in too close of proximity with each other.", "Such diapers take multiple drier cycles to completely dry, and generally result in stinky, damp diapers.", "The present diaper is easy to use, and allows the absorbency to be adjusted to accommodate the needs of both male and female.", "[0022] Finally, the present diaper is trimmer than other one-size, all-in-one diapers without eliminating of absorbency.", "Even in its largest size, permanently attached insert 30 provides two additional layers of absorbency, in addition to absorbent layer 20 .", "In FIGS. 4 and 5 , three additional layers of absorbency are provided in critical locations.", "In the diaper as adjusted to its smallest size, three additional layers of absorbency are provided.", "Thus for most applications one has at least four layers of absorbency, at least in the critical locations.", "Yet in the washing and drying cycle, there is realty only one layer of absorbency being washed and dried.", "[0023] Of course, it is understood that the foregoing describes preferred embodiments of the invention, and that changes and alterations can be made without departing from the spirit and scope of the invention as set forth in the appended claims." ]
INDEX TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/976,011 filed Sep. 28, 2007 the disclosure of which is incorporated by reference in its entirety. BRIEF SUMMARY OF THE INVENTION [0002] The present invention is a system for incorporating a humidifier into a vertical fan coil unit comprising: a. mounting a humidifier on the upper section of a fan coil unit; b. providing a fresh water inlet to said humidifier; and c. providing an outlet from said humidifier configured such that steam is incorporated into the outlet air stream of the fan coil. [0006] The system has a humidifier and/or steam generation unit and at least one steam dispersion outlet extending from said humidifier and/or steam generation unit. The steam dispersion outlet may be steam emitting nozzles or at least one steam dispersion tube. In one embodiment, the system includes an appropriate sensor to measure ambient indoor humidity and generating steam as needed to maintain the ambient humidity between about 25-50%. [0007] The steam generator ceases to operate if ambient humidity is over about 50% and operates if the ambient humidity drops below about 25%. [0008] The present invention provides for a system having a humidification unit incorporated in a typical vertical fan coil or vertical heat pump. The humidifier is mounted within the existing vertical fan coil housing and will have at least one steam generator and at least one steam dispersion device. Additionally, the humidifier will have a fresh water supply as the starting material for producing steam. In one embodiment, a fresh water supply may further comprise an in-line filter such that the unit provides steam that is generally free of particulate. [0009] The system of the present invention further comprises at least one sensor for detecting ambient humidity in the air space cooled or heated by the existing air conditioning and or heating system. The measuring of ambient humidity may be by any means currently known in the art. The transmission of information relating to the ambient humidity of a given enclosed area may be by any means currently known in the art. [0010] When the humidity sensor detects that ambient humidity has dropped below a preset value, the system will initiate steam generation in order to raise the humidity level and start the supply fan. When the humidity Sensor detects that the ambient humidity has exceeded a preset value, the system will cease to produce steam and shut off the supply fan. Typically, indoor ambient humidity is maintained at 25% to 50% in order for most persons to feel comfortable. [0011] The system of the present invention will incorporate a steam generation unit and a steam dispersion outlet to be mounted in the discharge duct. The steam dispersion outlet may be any acceptable outlets that will introduce steam into the outlet air flow of the existing air-conditioning or heating unit. The steam dispersion outlet may be a steam dispersion tube having one or more openings. Alternatively, the steam dispersion outlet may be one or more nozzles suitable for the delivery of steam. If nozzles are used, appropriate drain structures are in place to capture, accumulate and remove excess condensate that may develop in the nozzle region. [0012] The system of the present invention further includes at least one outlet to drain water from the steam generation device. Although this drain may remove water in any acceptable manner, a preferred manner would be to incorporate the drain of the steam generator with the existing drain riser in the air-conditioning or heating unit to be modified. [0013] In an alternative embodiment, steam generated from an external source may be delivered to the system of the present invention. For example, units that provide hot water on demand may be modified such that delivery of steam to the system of the present invention may be accomplished. In this embodiment, the steam dispersion will occur in the same manner as if the steam generation occurred within the existing vertical fan coil. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a front view of a vertical fan housing incorporating the present invention. [0015] FIG. 2 is a partial cut away view of the vertical fan housing of FIG. 1 . [0016] FIG. 3 is a side cut away view of the vertical fan housing of FIG. 1 . [0017] FIG. 4 is a top view of the vertical fan housing of FIG. 1 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] The system of the present invention includes a vertical fan coil housing 1 , modified to include a humidifier unit 2 . Fan 3 , is above a coil 16 , which is located on the interior underneath return air grille 12 . [0019] Partition wall 7 is positioned with a partition floor 22 a partition ceiling 23 to form a humidifier cavity 24 with sides of the cavity being the sides of vertical fan coil housing 1 and a closure formed by access door 10 . The cavity is an enclosure around humidifier 2 , such that humidifier 2 is not in the air stream that travels through chamber 21 . The air stream that enters return air grille 12 is propagated by fan 3 into chamber 21 exiting grille 6 into discharge plenum 11 and finally exiting at discharge grille 4 . Humidifier 2 includes a humidity gauge 13 , and a water inlet supply line 9 , optionally, the floor of discharge plenum 11 has plenum drain line 14 which connects to drain riser 5 at connection 17 . Humidifier drain line 19 is positioned under humidifier 2 and condensate accumulated inside humidifier 2 flows towards drain riser 5 where drain line 19 connects to drain riser 5 at humidifier drain line connector 18 . [0020] Vertical fan coil housing 1 also includes in discharge plenum 11 a steam dispersion tube 8 is mounted in discharge plenum 11 that delivers steam 15 to the air in discharge plenum 11 which combines with air exiting from chamber 21 through grille 6 and ultimately exits vertical fan coil housing 1 at discharge grille 4 . Steam dispersion tube 8 is mounted in the discharge ductwork and connectively piped to the humidity steam generator 2 . Plenum drain line 14 has a drain line inlet 24 positioned near the floor of discharge plenum 11 . Accumulated water is removed by entering drain line inlet 24 of plenum drain line 14 and is moved from the system where plenum drain line connector 19 attaches to drain riser 5 . [0021] The system provides an advantageous configuration in allowing access to all components through access door 10 on the front of vertical fan coil housing 1 . Steam 15 is produced within the vertical fan coil housing 1 and does not need to be transported to housing 1 . Ambient air flows into vertical fan coil housing 1 through return air grille 12 passes over coil 16 and is directed by fan 3 into air flow chamber 21 . Preferably, return air grille 12 is larger than discharge grille 4 . The ambient air exits chamber 21 through plenum grille 6 into discharge plenum 11 . Steam 15 generated within humidifier 2 is directed to steam transfer tube 20 and is dispersed into discharge plenum 11 through steam dispersion tube 8 . Steam transfer tube 20 is connectively piped to steam dispersion tube 8 mounted in the discharge ductwork. In a preferred embodiment, a minimum of eighteen inches of straight ductwork above dispersion tube 8 is desired. Air traveling through chamber 21 exits plenum grille 6 and combines with steam 15 in discharge plenum 11 . The mixture of air with steam exits vertical fan coil housing 1 through discharge grille 4 . [0022] Thus the unit of the present invention does not need to transport steam from outside vertical fan coil housing 1 . The unit produces steam 15 within vertical fan coil housing 1 by connection of a water inlet supply line 9 to a steam generating humidifier 2 placed within housing 1 . The aforementioned mixture of air with steam that exits vertical fan coil housing 1 through discharge grille 4 provides humidified air delivery through discharge grille 4 . [0023] While the invention has been described in its preferred form or embodiment with some degree of particularity, it is understood that this description has been given only by way of example and that numerous changes in the details of construction, fabrication, and use, including the combination and arrangement of parts, may be made without departing from the spirit and scope of the invention.
A system for incorporating a humidifier into a vertical fan coil unit mounting a humidifier on the upper section of a fan coil unit; providing a fresh water inlet to said humidifier; and providing an outlet from the humidifier configured such that steam is incorporated into the outlet air stream of the fan coil.
Summarize the document in concise, focusing on the main idea's functionality and advantages.
[ "INDEX TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application Ser.", "No. 60/976,011 filed Sep. 28, 2007 the disclosure of which is incorporated by reference in its entirety.", "BRIEF SUMMARY OF THE INVENTION [0002] The present invention is a system for incorporating a humidifier into a vertical fan coil unit comprising: a. mounting a humidifier on the upper section of a fan coil unit;", "b. providing a fresh water inlet to said humidifier;", "and c. providing an outlet from said humidifier configured such that steam is incorporated into the outlet air stream of the fan coil.", "[0006] The system has a humidifier and/or steam generation unit and at least one steam dispersion outlet extending from said humidifier and/or steam generation unit.", "The steam dispersion outlet may be steam emitting nozzles or at least one steam dispersion tube.", "In one embodiment, the system includes an appropriate sensor to measure ambient indoor humidity and generating steam as needed to maintain the ambient humidity between about 25-50%.", "[0007] The steam generator ceases to operate if ambient humidity is over about 50% and operates if the ambient humidity drops below about 25%.", "[0008] The present invention provides for a system having a humidification unit incorporated in a typical vertical fan coil or vertical heat pump.", "The humidifier is mounted within the existing vertical fan coil housing and will have at least one steam generator and at least one steam dispersion device.", "Additionally, the humidifier will have a fresh water supply as the starting material for producing steam.", "In one embodiment, a fresh water supply may further comprise an in-line filter such that the unit provides steam that is generally free of particulate.", "[0009] The system of the present invention further comprises at least one sensor for detecting ambient humidity in the air space cooled or heated by the existing air conditioning and or heating system.", "The measuring of ambient humidity may be by any means currently known in the art.", "The transmission of information relating to the ambient humidity of a given enclosed area may be by any means currently known in the art.", "[0010] When the humidity sensor detects that ambient humidity has dropped below a preset value, the system will initiate steam generation in order to raise the humidity level and start the supply fan.", "When the humidity Sensor detects that the ambient humidity has exceeded a preset value, the system will cease to produce steam and shut off the supply fan.", "Typically, indoor ambient humidity is maintained at 25% to 50% in order for most persons to feel comfortable.", "[0011] The system of the present invention will incorporate a steam generation unit and a steam dispersion outlet to be mounted in the discharge duct.", "The steam dispersion outlet may be any acceptable outlets that will introduce steam into the outlet air flow of the existing air-conditioning or heating unit.", "The steam dispersion outlet may be a steam dispersion tube having one or more openings.", "Alternatively, the steam dispersion outlet may be one or more nozzles suitable for the delivery of steam.", "If nozzles are used, appropriate drain structures are in place to capture, accumulate and remove excess condensate that may develop in the nozzle region.", "[0012] The system of the present invention further includes at least one outlet to drain water from the steam generation device.", "Although this drain may remove water in any acceptable manner, a preferred manner would be to incorporate the drain of the steam generator with the existing drain riser in the air-conditioning or heating unit to be modified.", "[0013] In an alternative embodiment, steam generated from an external source may be delivered to the system of the present invention.", "For example, units that provide hot water on demand may be modified such that delivery of steam to the system of the present invention may be accomplished.", "In this embodiment, the steam dispersion will occur in the same manner as if the steam generation occurred within the existing vertical fan coil.", "BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a front view of a vertical fan housing incorporating the present invention.", "[0015] FIG. 2 is a partial cut away view of the vertical fan housing of FIG. 1 .", "[0016] FIG. 3 is a side cut away view of the vertical fan housing of FIG. 1 .", "[0017] FIG. 4 is a top view of the vertical fan housing of FIG. 1 .", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] The system of the present invention includes a vertical fan coil housing 1 , modified to include a humidifier unit 2 .", "Fan 3 , is above a coil 16 , which is located on the interior underneath return air grille 12 .", "[0019] Partition wall 7 is positioned with a partition floor 22 a partition ceiling 23 to form a humidifier cavity 24 with sides of the cavity being the sides of vertical fan coil housing 1 and a closure formed by access door 10 .", "The cavity is an enclosure around humidifier 2 , such that humidifier 2 is not in the air stream that travels through chamber 21 .", "The air stream that enters return air grille 12 is propagated by fan 3 into chamber 21 exiting grille 6 into discharge plenum 11 and finally exiting at discharge grille 4 .", "Humidifier 2 includes a humidity gauge 13 , and a water inlet supply line 9 , optionally, the floor of discharge plenum 11 has plenum drain line 14 which connects to drain riser 5 at connection 17 .", "Humidifier drain line 19 is positioned under humidifier 2 and condensate accumulated inside humidifier 2 flows towards drain riser 5 where drain line 19 connects to drain riser 5 at humidifier drain line connector 18 .", "[0020] Vertical fan coil housing 1 also includes in discharge plenum 11 a steam dispersion tube 8 is mounted in discharge plenum 11 that delivers steam 15 to the air in discharge plenum 11 which combines with air exiting from chamber 21 through grille 6 and ultimately exits vertical fan coil housing 1 at discharge grille 4 .", "Steam dispersion tube 8 is mounted in the discharge ductwork and connectively piped to the humidity steam generator 2 .", "Plenum drain line 14 has a drain line inlet 24 positioned near the floor of discharge plenum 11 .", "Accumulated water is removed by entering drain line inlet 24 of plenum drain line 14 and is moved from the system where plenum drain line connector 19 attaches to drain riser 5 .", "[0021] The system provides an advantageous configuration in allowing access to all components through access door 10 on the front of vertical fan coil housing 1 .", "Steam 15 is produced within the vertical fan coil housing 1 and does not need to be transported to housing 1 .", "Ambient air flows into vertical fan coil housing 1 through return air grille 12 passes over coil 16 and is directed by fan 3 into air flow chamber 21 .", "Preferably, return air grille 12 is larger than discharge grille 4 .", "The ambient air exits chamber 21 through plenum grille 6 into discharge plenum 11 .", "Steam 15 generated within humidifier 2 is directed to steam transfer tube 20 and is dispersed into discharge plenum 11 through steam dispersion tube 8 .", "Steam transfer tube 20 is connectively piped to steam dispersion tube 8 mounted in the discharge ductwork.", "In a preferred embodiment, a minimum of eighteen inches of straight ductwork above dispersion tube 8 is desired.", "Air traveling through chamber 21 exits plenum grille 6 and combines with steam 15 in discharge plenum 11 .", "The mixture of air with steam exits vertical fan coil housing 1 through discharge grille 4 .", "[0022] Thus the unit of the present invention does not need to transport steam from outside vertical fan coil housing 1 .", "The unit produces steam 15 within vertical fan coil housing 1 by connection of a water inlet supply line 9 to a steam generating humidifier 2 placed within housing 1 .", "The aforementioned mixture of air with steam that exits vertical fan coil housing 1 through discharge grille 4 provides humidified air delivery through discharge grille 4 .", "[0023] While the invention has been described in its preferred form or embodiment with some degree of particularity, it is understood that this description has been given only by way of example and that numerous changes in the details of construction, fabrication, and use, including the combination and arrangement of parts, may be made without departing from the spirit and scope of the invention." ]
FIELD OF THE INVENTION [0001] The invention relates to an apparatus and method for demodulating a received IF DPSK signal. BACKGROUND OF THE INVENTION [0002] Phase Shift Keying (PSK) and Differential Phase Shift Keying (DPSK) modulation schemes are widely used in wireless communication. In DPSK, the phase of the carrier is discretely varied in relation to the phase of the immediately preceding signal element in accordance with the data being transmitted. Differential Quadrature Phase Shift Keying (DQPSK) and Differential Bi-Phase Shift Keying (DBPSK) are other variations. [0003] DQPSK is often employed in wireless Local Area Network (WLAN) systems, 8DPSK is used in some Bluetooth medium rate systems and π 4 ⁢ DQPSK is used in a number of applications including Time Division Multiple Access (TDMA) systems, IS-54 and IS-136 (which are two standards of cellular systems deployed in the United States, IS-54 being the US TDMA standard with an analog control channel and IS-136 being the US TDMA standard with a digital control channel), some Bluetooth medium rate systems, PHS (“Personal Handy Phone System”, ARIB Standard, Version 4.0, February 2003), Inter-Vehicle Communication (IVC) and Terrestrial Trunked Radio (TETRA) systems. Obviously, it is particularly important for the mobile stations used in wireless communication to limit power consumption as much as possible. [0004] In traditional demodulators for DPSK signals, an analogue to digital converter (ADC) is used to convert the received analogue signal (either a baseband signal or an intermediate frequency (IF) signal) into digital form for further processing. One drawback of this arrangement is that ADCs typically consume a lot of power (which is particularly disadvantageous for mobile receivers). Another drawback is that the design and implementation costs are rather high because of the power-hungry ADC. [0005] There have been several attempts to solve the problem of high power consumption and high design cost in traditional DPSK demodulators and some of these are described in U.S. Pat. No. 3,997,847, U.S. Pat. No. 5,122,758, U.S. Pat. No. 5,539,776, U.S. Pat. No. 5,640,427, U.S. Pat. No. 5,945,875 and “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems”, Hideho TOMITA, Yukio YOKOYAMA, Toru MATSUKI, Global Telecommunications Conference, 1990, and Exhibition “Communications: Connecting the Future”, GLOBECOM '90, IEEE. All those designs DPSK demodulate an IF hard limited signal, the key technology being to use a counter for zero-crossing detection and to determine the phase difference using those counters. Because of this, no ADC is required since the digitization is performed by the hard limiter which generates a logical signal, which can take one of 2-levels (i.e. it is 1 bit), from the incoming analogue signal. No ADC is an advantage as the design complexity can be reduced, but there are some disadvantages with these systems. Firstly, a very high sampling rate (sometimes as high as 100 times the intermediate frequency) is required to ensure acceptable performance. This is because the hard limiter works as a 1-bit ADC and the counter is used to do phase difference detection. Thus, the arrangement is not very complex so, to compensate for the consequent low resolution, a very high sampling rate is necessary. This obviously means high power consumption. Secondly, the performance in terms of Bit Error Rate (BER) is actually much worse that traditional arrangements using an ADC. In fact, in the scheme described in “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems” (mentioned above), the performance at a BER of 10 −4 is about 3 dB worse than the performance of a traditional ADC arrangement. SUMMARY OF THE INVENTION [0006] It is an object of the invention to provide a demodulator for DPSK signals and a method for demodulating DPSK signals which mitigate or substantially overcome the problems of known arrangements and methods described above. [0007] According to the invention, there is provided apparatus for demodulating a received hard limited DPSK signal, the apparatus comprising: [0008] a digital down converter (DDC) for generating an in-phase component I and a quadrature component Q of a received signal; [0009] at least one decimator for reducing sampling frequency of the received signal; [0010] at least one filter for reducing noise outside a required bandwidth; and [0011] a differential decoder for performing differential detection of I and Q over a given symbol span. [0012] Because the received signal is hard limited, no ADC is required, which reduces design complexity compared with traditional arrangements. In addition, inclusion of the DDC, decimator, filter and differential decoder means than the sampling rate can be reduced compared with known arrangements incorporating a hard limiter. Thus, both complexity and sampling rate are improved. [0013] In one embodiment, the DDC is upstream of the at least one decimator and the at least one decimator comprises one decimator for the I component and one decimator for the Q component. [0014] In another embodiment, the DDC is downstream of the at least one decimator and the at least one decimator comprises only one decimator for the received signal. This second embodiment is advantageous because only a single decimator is required. In addition, since the decimator is upstream of the DDC, the operating frequency of the DDC is reduced. [0015] Preferably, the DDC is arranged to generate the in-phase component I by multiplying the received signal by a cosine function and to generate the quadrature component Q by multiplying the received signal by a sine function. [0016] Preferably, the DDC operates at a frequency which is a predetermined number of times greater than the frequency of the received signal. In one embodiment, the DDC is arranged to operate at a frequency that is four times the frequency of the received signal, in which case the cosine function is simplified to the values {1, 0, −1, 0} over each cycle of the received signal and the sine function is simplified to the values {0, 1, 0, −1} over each cycle of the received signal. This allows the structure of the DDC to be simplified. Other simplifications could also be envisaged, for example if the operating frequency of the DDC were twice the frequency of the received signal. [0017] In one arrangement, the or each of the at least one decimator comprises a cascaded integrator comb (CIC) filter. A CIC filter is advantageous for performing decimation since it does not include multipliers. [0018] Preferably, the CIC filter comprises N integrator stages, N comb stages and a downsampler for reducing the sampling rate of the received signal. The down sampler may reduce the sampling rate by a factor of R. Each comb stage may introduce a delay of M to the CIC filter. The CIC filter may have the frequency response: H ⁡ ( ω ) = ( 1 - ⅇ - ⅈ ⁢   ⁢ RM ⁢   ⁢ ω ) N ( 1 - z - ⅈ ⁢   ⁢ ω ) N where ω is the frequency of the received signal. [0019] In another arrangement, the or each of the at least one decimator is a finite impulse response (FIR) filter. [0020] In one preferred embodiment, the or each of the at least one filter is arranged to perform pulse shaping of the received signal. [0021] In that embodiment, the or each of the at least one filter may comprise all or part of a raised cosine filter. [0022] In one case, the or each of the at least one filter may comprise a root raised cosine (RRC) filter. In that case, there will usually be at least one other RRC filter in the transmitter which transmitted the signals. The at least one RRC filter in the receiver together with the at least one RRC filter in the transmitter together provide raised cosine function pulse shaping of the signal. The or each RRC filter may comprise 49 taps. [0023] In an alternative embodiment, the or each of the at least one filter may comprise a low pass filter. [0024] The differential decoder may be arranged to perform differential detection of I and Q over a symbol span of one symbol. Of course, other symbol spans can also be envisaged. [0025] In one embodiment, the differential decoder comprises a decision block for converting the differentially decoded I into an I output and for converting the differentially decoded Q into a Q output, the I output and the Q output each taking a value of either 0 or 1. [0026] In that embodiment, the I decision may be: if the differentially decoded I is greater than zero, the I output is 0 and, if the differentially decoded I is less than zero, the I output is 1. In that embodiment, the Q decision may be: if the differentially decoded Q is greater than zero, the Q output is 0 and, if the differentially decoded Q is less than zero, the Q output is 1. [0027] In one embodiment, the apparatus further comprises a hard limiter for hard limiting the received DPSK signal. [0028] Preferably, the received signal is an intermediate frequency (IF) signal. Alternatively, the received signal may be a baseband signal. [0029] In one embodiment, the received signal is π 4 ⁢ DQPSK modulated. [0030] According to the invention, there is also provided a receiver for DPSK signals, the receiver comprising apparatus as described above. [0031] According to the invention, there is also provided a method for demodulating a received hard limited DPSK signal, the method comprising the steps of: [0032] a) generating an in-phase component I and a quadrature component Q from a received signal; [0033] b) reducing sampling frequency of the received signal; [0034] c) reducing noise outside a required bandwidth; and [0035] d) performing differential detection of I and Q over a given symbol span. [0036] In a first embodiment, step a) is performed before step b) and step b) comprises the steps of reducing sampling frequency of the in-phase component I and reducing sampling frequency of the quadrature component Q. [0037] In a second embodiment, step a) is performed after step b). The second embodiment is advantageous because only a single decimating step is required for the entire received signal rather than separate decimating steps for I and for Q. [0038] Preferably, step a) comprises multiplying the received signal by a cosine function to generate the in-phase component I and multiplying the received signal by a sine function to generate the quadrature component Q. [0039] Step a) of the method may be performed in a digital down converter (DDC). [0040] Step b) of the method may be performed in a cascaded integrator comb (CIC) filter. A CIC filter is advantageous for performing decimation since it does not includes multipliers. Preferably, the CIC filter comprises N integrator stages, N comb stages and a down sampler for reducing the sampling rate. The down sampler may reduce the sampling rate by a factor of R. Each comb stage may introduce a time delay of M to the CIC filter. [0041] Alternatively, step b) of the method may be performed in a single finite impulse response (FIR) filter. [0042] Step c) of the method may be performed in a low pass filter. [0043] In one embodiment, the method further comprises the step of pulse shaping the received signal. [0044] In that embodiment, in a first case, the step of reducing noise outside the required bandwidth and the step of pulse shaping the received signal may both be performed in a raised cosine filter. [0045] Alternatively, in a second case, the step of reducing noise outside the required bandwidth and the step of pulse shaping the received signal may be performed in a root raised cosine (RRC) filter. In the second case, there will usually be at least one other RRC filter in a transmitter which transmitted the signals. [0046] Step d) may comprise performing differential detection of I and Q over a symbol span of one symbol. [0047] The method may further comprise the steps of converting the differentially decoded I into an I output and converting the differentially decoded Q into a Q output, the I output and the Q output each taking a value of either 0 or 1. In that case, it may be set that, if the differentially decoded I is greater than zero, the I output is 0 and, if the differentially decoded I is less than zero, the I output is 1. Also, in that case, it may be set that, if the differentially decoded Q is greater than zero, the Q output is 0 and, if the differentially decoded Q is less than zero, the Q output is 1. [0048] In one embodiment, the method further comprises, before step a), the step of hard limiting the received DPSK signal. [0049] Preferably, the received signal is an intermediate frequency (IF) signal. Alternatively, the received signal may be a baseband signal. [0050] The received signal may be π 4 ⁢ DQPSK modulated. [0051] According to the invention there is also provided apparatus for carrying out the method described above. [0052] According to the invention there is also provided a receiver for DPSK signals, for carrying out the method described above. [0053] Features described in relation to the apparatus of the invention may also be applicable to the method of the invention and features described in relation to the method of the invention may also be applicable to the apparatus of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0054] By way of example, preferred embodiments of the invention will now be described with reference to the accompanying drawings, of which: [0055] FIG. 1 is a diagram of a demodulator according to a first embodiment of the invention; [0056] FIG. 2 is a detailed diagram of block 103 of FIG. 1 ; [0057] FIG. 3 is a detailed diagram of blocks 105 a and 105 b of FIG. 1 [0058] FIG. 4 is a detailed diagram of blocks 107 a and 107 b of FIG. 1 ; [0059] FIG. 5 is a graph showing performance of the demodulator of FIG. 1 at three different sampling rates; [0060] FIG. 6 is a diagram of a demodulator according to a second embodiment of the invention; [0061] FIG. 7 is a detailed diagram of block 605 of FIG. 6 ; [0062] FIG. 8 is a graph showing performance of the demodulators of FIGS. 1 and 6 ; and [0063] FIG. 9 is a diagram of a demodulator according to a third embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0064] All the described embodiments show demodulators for π 4 ⁢ DQPSK , but the invention is not limited to π 4 ⁢ DQPSK and could apply to any differentially encoded PSK signal. Also, for all three described demodulators, the input is a 2-level (i.e. 1 bit) IF signal from an IF hard limiter. However, although the major application of the invention is IF signals, the invention could also be used with baseband. [0065] FIG. 1 shows a block diagram of a π 4 ⁢ DQPSK demodulator 101 according to a first embodiment of the invention. The demodulator includes a Digital Down Converter (DDC) 103 , Cascaded Integrator Comb (CIC) filters 105 a and 105 b , Root Raised Cosine (RRC) filters 107 a and 107 b , a differential decoder 109 and a decision block 111 . The input to the demodulator 101 is a 2-level (i.e. 1 bit) IF signal from an IF hard limiter (not shown). The outputs of the demodulator 101 are I and Q signals. [0066] FIG. 2 shows the DDC 103 of FIG. 1 in more detail. Digital down conversion is used to recover the in-phase component I and the quadrature component Q from the received IF signal. The IF signal can be expressed as: S k =A k cos{2π f IF kT s +φ k } where k is the sample number (also known as the order), A k is amplitude of the sampled IF signal at sample k, f IF is the intermediate frequency, T s is the time between one sample and the next i.e. the sampling interval and φ k is the phase of the sampled IF signal at sample k. [0067] T s (which is equal to 1 f s , f s being the sampling frequency) is chosen so that f s is as low as possible to still obtain acceptable performance in the demodulator given f IF . We can obtain acceptable performance with this arrangement with a sampling frequency f s much lower than the sampling frequency in known arrangements which use a hard limiter to digitize the incoming signal, as discussed previously. This is because, by sacrificing some of the reduced complexity of known hard limiter arrangements, we can obtain a huge decrease in required sampling rate. [0068] As shown in FIG. 2 , the I channel is formed by multiplying S k by cos{2πf IF kT s } at block 201 and the Q channel is formed by multiplying S k by sin{2πf IF kT s } at block 203 . The resulting I and Q components therefore have the form: I k =A k cos{2 πf IF kT s +φ k }cos{2 πf IF kT s } and Q k =A k cos{2 πf IF kT s +φ k }sin{2 πf IF kT s } [0069] FIG. 3 shows each CIC filter 105 a , 105 b of FIG. 1 in more detail. The CIC filters are used to perform decimation. A CIC filter is very efficient for performing decimation (or interpolation) since it does not contain multipliers. [0070] As shown in FIG. 3 , each CIC filter 105 a , 105 b comprises an integrator portion 301 and a comb portion 303 . Between the integrator portion 301 and the comb portion 303 there is a down sampler 305 for reducing the sampling rate by a factor R. The integrator portion comprises N integrator stages 307 clocked at rate f s = 1 T s . As is well known, each integrator stage is simply an infinite impulse response (IIR) filter which acts like a low pass filter. The comb portion comprises N comb stages 309 clocked at rate f s R = 1 RT s . Similarly, each comb stage is simply a finite impulse response (FIR) filter which acts like a high pass filter. [0071] The CIC filter may have the frequency response: H ⁡ ( ω ) = ( 1 - ⅇ - ⅈ ⁢   ⁢ RM ⁢   ⁢ ω ) N ( 1 - ⅇ - ⅈω ) N where ω is the frequency of the received signal and M is the time delay at each comb stage of the CIC filter. [0072] To reduce the power consumption of the subsequent RRC filter 107 , the higher the decimation rate of the CIC filter 105 , the better. However, greater decimation obviously means some degradation in performance. Thus, a compromise must be found between low sampling rate in the RRC and good BER performance of the demodulator. So, we choose R, M and N appropriately for the required frequency response of the CIC filter. [0073] FIG. 4 shows each RRC filter 107 a , 107 b of FIG. 1 in more detail. In this embodiment, RRC filters are used in the receiver since there will also be RRC filters (not shown) in the transmitter, meaning that the overall pulse shaping follows the raised cosine function (since the overall effect of the two filters is the product of the two functions). Alternatively, if there were no RRC filters in the transmitter, we could incorporate raised cosine filters in FIG. 1 instead of RRC filters. [0074] In any case, the purpose of the RRC filters is to perform pulse shaping to reduce the bandwidth of the over sampled symbol stream without introducing inter symbol interference and also to reduce noise outside the required bandwidth. [0075] Referring to FIG. 4 , each RRC filter 107 a , 107 b comprises 49 taps 401 in succession. Any number of taps could be chosen for the RRC filter (as long as the filter's frequency response meets the system requirements) but we prefer an odd number of taps so that the centre of the filter's impulse response will be a peak (rather than two equal values). Also, the greater the number of taps, the more attenuation there will be outside the desired bandwidth, but the greater the filter complexity and delay. [0076] Referring once again to FIG. 1 , after the RRC filters 107 a and 107 b , the I and Q signals are input into the differential decoder 109 . The differential decoder comprises buffers 113 a and 113 b , multipliers 115 a , 115 b , 115 c and 115 d and adders 117 a and 117 b . The differential decoder 109 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0077] This can be seen clearly from block 109 in FIG. 1 . The I in (k) signal is input into buffer 113 a , multiplier 115 a and multiplier 115 c . The Q in (k) signal is input into buffer 113 b , multiplier 115 b and multiplier 115 d . The buffer 113 a outputs the I signal from the previous sample i.e. I in (k−1) and stores the I in (k) signal for the next iteration. Similarly, the buffer 113 b outputs the Q signal from the previous sample i.e. Q in (k−1) and stores the Q in (k) signal for the next iteration. The output of multiplier 115 a is I(k)*I(k−1), the output of the multiplier 115 b is Q(k)*I(k−1), the output of multiplier 115 c is I(k)*Q(k−1) and the output of multiplier 115 d is Q(k)*Q(k−1). The outputs from multipliers 115 a and 115 d are input into adder 117 a producing I(k)I(k−1)+Q(k)Q(k−1) i.e. I out (k). The outputs from multipliers 115 b and 115 c are input into adder 117 b producing Q(k)I(k−1)−I(k)Q(k−1) i.e. Q out (k). [0078] After the differential decoder 109 , the I and Q signals are input into the decision block 111 . The decision rule might be something like [0000] if I out >0, I=0 else I=1 [0000] If Q out >0, Q=0 else Q=1 [0000] or any other suitable decision algorithm. [0079] FIG. 5 shows performance of the demodulator of FIG. 1 under three different test conditions. In all three cases, the symbol rate was 2.048 Mbps, the intermediate frequency f IF was 8.192 MHz and the CIC filter comprised two stages, with a decimation rate of R=4 (i.e. the decoding rate was always ¼ of the sampling rate). FIG. 5 is a plot of Eb No expressed in dB on the x-axis versus bit error ratio (BER) on the y-axis. Eb is the energy in one bit and No is the noise power in a 1 Hz bandwidth. So the numerical ratio Eb No is a form of signal to noise ratio. Thus, in FIG. 5 , the BER is shown as a function of Eb No i.e. in terms of the probability of error. [0080] In graph A, the sampling rate f s was 131.072 MHz (i.e. 16 times the intermediate frequency) and the decoding rate was 32.768 MHz. In graph B, the sampling rate f s was 262.144 MHz (i.e. 32 times the intermediate frequency) and the decoding rate was 65.536 MHz. In graph C, the sampling rate f s was 524.288 MHz (i.e. 64 times the intermediate frequency) and the decoding rate was 131.072 MHz. FIG. 5 also shows the theoretical result—graph D. [0081] It can be seen from FIG. 5 that the BER performance is better than that of prior art systems. In particular, this embodiment shows an improvement of 1.5 dB at a BER of 10 −4 over the system described in “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems”, Hideho TOMITA, Yukio YOKOYAMA, Toru MATSUKI, Global Telecommunications Conference, 1990, and Exhibition “Communications: Connecting the Future”, GLOBECOM '90, IEEE, which was mentioned earlier. In addition, the sampling rate is lower: up to only 16 times the intermediate frequency as opposed to at least 32 times the intermediate frequency (and possibly as high as 100 times the intermediate frequency) in prior art systems. [0082] FIG. 6 shows a block diagram of a f s = 1 T s , demodulator 601 according to a second embodiment of the invention. The FIG. 6 arrangement is similar to the FIG. 1 arrangement and includes a CIC filter 603 , a DDC 605 , RRC filters 607 a and 607 b , a differential decoder 609 and a decision block 611 . As with FIG. 1 , the input to the demodulator 601 is the 2-level IF signal from an IF hard limiter (not shown) and the outputs of the demodulator 601 are I and Q signals. [0083] The FIG. 6 arrangement differs from the FIG. 1 arrangement in that the CIC filter 603 is upstream of the DDC 605 . There are several advantages in swapping the positions of the CIC filter(s) and the DDC which will be discussed below. [0084] The CIC filter 603 has a structure just like that shown in FIG. 3 . There is an integrator portion comprising N integrator stages clocked at rate π 4 ⁢ DQPSK followed by a down sampler for reducing the clock rate by a factor R, followed by a comb portion comprising N comb stages clocked at rate f s R = 1 RT s . Once again, we choose R, M and N appropriately depending on the required frequency response of the CIC filter. [0085] Obviously, with the arrangement of FIG. 6 , only a single CIC filter is required since the I and Q signals have not yet been isolated; this is one advantage of the FIG. 6 arrangement. Also, the CIC filter can be greatly simplified as explained below. [0086] In a CIC filter, the bit width growth is very fast. The output bit width can be shown to be: B out =┌N log 2 RM+B in ┐ where B in is the input bit width, B out is the output bit width, N is the number of CIC filter stages, R is the decimation ratio (i.e. the reduction of sampling rate as performed in the downsampler 305 ) and M is the delay in each comb unit. Therefore, the adders could have a rather large bit width. Moreover the B out bits are needed for every adder. [0087] In order to compare the FIG. 1 and FIG. 6 arrangements fairly, we set R=8 for the FIG. 1 arrangement and R=4 for the FIG. 6 arrangement. For both arrangements, we assume that N=2 and M=1. For the arrangement of FIG. 1 , the input to the CIC is the output of the DDC, which must be at least 4 bits to ensure acceptable performance in the DDC. Thus, for N=2, R=8, M=1 and B in =4, B out is 10. On the other hand, for the arrangement of FIG. 6 , the input to the CIC is the output of the hard limiter which is just 1 bit. So, for N=2, R=4, M=1 and B in =1, B out is only 5. Thus, the output bit width can be reduced with the FIG. 6 arrangement, which is clearly advantageous. [0088] Referring once again to FIG. 6 , from the CIC filter 603 , the signal is input to DDC 605 . In the FIG. 6 arrangement, the clock rate of the DDC can be reduced since the CIC filter has already performed decimation; this is advantageous since it reduces power consumption. So, whereas previously the DDC clock rate was f s , the DDC clock rate can now be 4 ⁢ Rf IF R = 4 ⁢ f IF . Also, if we set the sampling frequency f s appropriately, the DDC structure can be simplified as will now be explained. [0089] If we set the sampling frequency f s in the CIC to be 4Rf IF , the sampling rate in the DDC is f s R . Considering the DDC structure shown in FIG. 2 , we see that the I channel is produced by multiplying the incoming signal by cos{2πf IF kT s } and the Q channel is produced by multiplying the incoming signal by sin{2πf IF kT s }. However, since the DDC rate is four times that of the intermediate frequency, we can simplify the cosine and sine functions. This is because, over one cycle, cos x takes the values 1, 0, −1 and 0 and sin x takes the values 0, 1, 0 and −1. We can make use of this to simplify the DDC as shown in FIG. 7 . [0090] Referring to FIG. 7 , the incoming signal S k is multiplied by 1, 0, −1 and 0 at successive samples at block 701 to produce the I channel. The resulting I components are therefore of the forms: [0000] I k =S k ,0,−S k ,0 over a single cycle of the IF signal. [0091] The incoming signal S k is multiplied by 0, 1, 0 and −1 at successive samples at block 703 to produce the Q channel. The resulting Q components are therefore of the forms: [0000] Q k =0,S k ,0,−S k over a single cycle of the intermediate frequency signal. [0092] (We may be able to make a similar simplification to the DDC in the FIG. 1 arrangement. However, this is less likely since the clock rate of the DDC in that arrangement has to be f s (because the DDC comes before the CIC filter) and it is unlikely that we can obtain acceptable performance with a sampling frequency only four times the intermediate frequency.) [0093] Referring once again to FIG. 6 , the I and Q signals are then input to RRC filters 607 a and 607 b respectively. The RRC filters are used for pulse shaping the symbol stream without the introduction of inter symbol interference and also for reduction of noise outside the desired bandwidth and each RRC filter may have the structure shown in FIG. 4 . [0094] From RRC filter 607 a the I signal is input to the differential decoder 609 and from RRC filter 607 b , the Q signal is input to the differential decoder 609 . As before, the differential decoder comprises buffers 613 a and 613 b , multipliers 615 a , 615 b , 615 c and 615 d and adders 617 a and 617 b . The differential decoder 609 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0095] After the differential decoder 609 , the I and Q signals are input into the decision block 611 , which produces I and Q outputs from the differentially decoded I and Q. [0096] (In the FIG. 6 arrangement, we moved the CIC filter upstream of the DDC which brought several advantages. It would be possible to also bring the RRC upstream of the DDC. However, this arrangement will result in a complex filter before the DDC and the complexity of this complex filter is usually higher than the complexity of the two RRC filters. Also, to reject the out-of-band noise and higher frequency components of the DDC output, some kind of low pass filter may still be required after the DDC, even if a complex filter is used before the DDC. Therefore, although possible, this arrangement may not provide any additional advantages.) [0097] FIG. 8 shows performance of the demodulator of FIG. 1 and performance of the demodulator of FIG. 6 for a symbol rate of 2.048 Mbps, an intermediate frequency f IF of 8.192 MHz and a sampling rate of 131.072 MHz (i.e. 16 times the intermediate frequency). Like FIG. 5 , FIG. 8 is a plot of Eb No expressed in dB on the x-axis versus bit error ratio (BER) on the y-axis. As before, for a fair comparison of the FIG. 1 and FIG. 6 arrangements, we set the decimation rate R to be 8 for the FIG. 1 arrangement (plot E) and we set the decimation rate R to be 4 for the FIG. 6 arrangement (plot F). Once again, the theoretical result D is shown for comparison. [0098] It can be seen that the two embodiments (shown in FIGS. 1 and 6 ) produce almost exactly the same results. So, for both these embodiments, the BER performance shows an improvement over prior art BER performance and the sampling rate is lower. [0099] FIG. 9 shows a block diagram of a π 4 ⁢ DQPSK demodulator 901 according to a third embodiment of the invention. The FIG. 9 arrangement is similar to that of FIG. 6 but the CIC filter 603 has been replaced by a generic decimation filter 903 and the RRC filters 607 a and 607 b have been replaced by simple low pass filters (LPF) 907 a and 907 b . Thus, the arrangement includes a Decimation Filter (DF) 903 , a DDC 905 , LPFs 907 a and 907 b , a differential decoder 909 and a decision block 911 . As with FIGS. 1 and 6 , the input to the demodulator 901 is the 2-level IF signal from an IF hard limiter (not shown) and the outputs of the demodulator 901 are I and Q signals. [0100] The DF 903 is simply a general decimation filter for example a FIR filter. The purpose of the DF is to reduce the sampling rate. [0101] From the DF 903 , the signal is input to DDC 905 . The DDC structure may have the structure shown in FIG. 2 to produce I and Q channels by multiplication by cos{ 2πf IF kT s } and sin{2πf IF kT s }respectively. Or, the DDC structure could be simplified like DDC 605 in FIG. 6 . For example if the sampling rate of the DDC is four times the intermediate frequency, we can make use of the fact that the cosine function takes the values 1, 0, −1, 0 over each IF cycle and the sine function takes the values 0, 1, 0, −1 over each IF cycle. [0102] From the DDC 905 , the I and Q signals are input to the LPFs 907 a and 907 b . As already mentioned, the RRC filters in FIGS. 1 and 6 are used for pulse shaping and rejection of noise outside the required bandwidth. The pulse shaping was performed by the raised cosine function either by having RRC filter(s) in the transmitter side and RRC filter(s) in the receiver side, or by implementing the entire raised cosine function in the receiver side (i.e. doing no pulse shaping at all in the transmitter). If we now choose to do all the pulse shaping in the transmitter, we don't need to have even a RRC filter in the receiver. However, some kind of filter is still required to reduce noise outside the required bandwidth and interference, so we use simple low pass filters 907 a and 907 b . By performing all the pulse shaping on the transmitter side, the structure of the receiver can be simplified. [0103] From LPF 907 a , the I signal is input to the differential decoder 909 and from LPF 907 b , the Q signal is input to the differential decoder 909 . As before, the differential decoder comprises buffers 913 a and 913 b , multipliers 915 a , 915 b , 915 c and 915 d and adders 917 a and 917 b . The differential decoder 909 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0104] After the differential decoder 909 , the I and Q signals are input into the decision block 911 . [0105] Thus, in all the described embodiments, there is a lower power consumption because of the lower required sampling rate. Also, the performance in terms of BER is improved over prior art demodulators as shown in FIGS. 5 and 8 .
There is provided a method and apparatus for demodulating a received hard limited DPSK signal, which may be an intermediate frequency (IF) signal. The apparatus comprises: a digital down converter for generating an in-phase component I and a quadrature component Q of a received signal; at least one decimator for reducing sampling frequency of the received signal; at least one filter for reducing noise outside a required bandwidth; and a differential decoder for performing differential detection of I and Q over a given symbol span. The method comprises the steps of: generating an in-phase component I and a quadrature component Q from a received signal; reducing sampling frequency of the received signal; reducing noise outside a required bandwidth; and performing differential detection of I and Q over a given symbol span.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "FIELD OF THE INVENTION [0001] The invention relates to an apparatus and method for demodulating a received IF DPSK signal.", "BACKGROUND OF THE INVENTION [0002] Phase Shift Keying (PSK) and Differential Phase Shift Keying (DPSK) modulation schemes are widely used in wireless communication.", "In DPSK, the phase of the carrier is discretely varied in relation to the phase of the immediately preceding signal element in accordance with the data being transmitted.", "Differential Quadrature Phase Shift Keying (DQPSK) and Differential Bi-Phase Shift Keying (DBPSK) are other variations.", "[0003] DQPSK is often employed in wireless Local Area Network (WLAN) systems, 8DPSK is used in some Bluetooth medium rate systems and π 4 ⁢ DQPSK is used in a number of applications including Time Division Multiple Access (TDMA) systems, IS-54 and IS-136 (which are two standards of cellular systems deployed in the United States, IS-54 being the US TDMA standard with an analog control channel and IS-136 being the US TDMA standard with a digital control channel), some Bluetooth medium rate systems, PHS (“Personal Handy Phone System”, ARIB Standard, Version 4.0, February 2003), Inter-Vehicle Communication (IVC) and Terrestrial Trunked Radio (TETRA) systems.", "Obviously, it is particularly important for the mobile stations used in wireless communication to limit power consumption as much as possible.", "[0004] In traditional demodulators for DPSK signals, an analogue to digital converter (ADC) is used to convert the received analogue signal (either a baseband signal or an intermediate frequency (IF) signal) into digital form for further processing.", "One drawback of this arrangement is that ADCs typically consume a lot of power (which is particularly disadvantageous for mobile receivers).", "Another drawback is that the design and implementation costs are rather high because of the power-hungry ADC.", "[0005] There have been several attempts to solve the problem of high power consumption and high design cost in traditional DPSK demodulators and some of these are described in U.S. Pat. No. 3,997,847, U.S. Pat. No. 5,122,758, U.S. Pat. No. 5,539,776, U.S. Pat. No. 5,640,427, U.S. Pat. No. 5,945,875 and “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems”, Hideho TOMITA, Yukio YOKOYAMA, Toru MATSUKI, Global Telecommunications Conference, 1990, and Exhibition “Communications: Connecting the Future”, GLOBECOM '90, IEEE.", "All those designs DPSK demodulate an IF hard limited signal, the key technology being to use a counter for zero-crossing detection and to determine the phase difference using those counters.", "Because of this, no ADC is required since the digitization is performed by the hard limiter which generates a logical signal, which can take one of 2-levels (i.e. it is 1 bit), from the incoming analogue signal.", "No ADC is an advantage as the design complexity can be reduced, but there are some disadvantages with these systems.", "Firstly, a very high sampling rate (sometimes as high as 100 times the intermediate frequency) is required to ensure acceptable performance.", "This is because the hard limiter works as a 1-bit ADC and the counter is used to do phase difference detection.", "Thus, the arrangement is not very complex so, to compensate for the consequent low resolution, a very high sampling rate is necessary.", "This obviously means high power consumption.", "Secondly, the performance in terms of Bit Error Rate (BER) is actually much worse that traditional arrangements using an ADC.", "In fact, in the scheme described in “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems”", "(mentioned above), the performance at a BER of 10 −4 is about 3 dB worse than the performance of a traditional ADC arrangement.", "SUMMARY OF THE INVENTION [0006] It is an object of the invention to provide a demodulator for DPSK signals and a method for demodulating DPSK signals which mitigate or substantially overcome the problems of known arrangements and methods described above.", "[0007] According to the invention, there is provided apparatus for demodulating a received hard limited DPSK signal, the apparatus comprising: [0008] a digital down converter (DDC) for generating an in-phase component I and a quadrature component Q of a received signal;", "[0009] at least one decimator for reducing sampling frequency of the received signal;", "[0010] at least one filter for reducing noise outside a required bandwidth;", "and [0011] a differential decoder for performing differential detection of I and Q over a given symbol span.", "[0012] Because the received signal is hard limited, no ADC is required, which reduces design complexity compared with traditional arrangements.", "In addition, inclusion of the DDC, decimator, filter and differential decoder means than the sampling rate can be reduced compared with known arrangements incorporating a hard limiter.", "Thus, both complexity and sampling rate are improved.", "[0013] In one embodiment, the DDC is upstream of the at least one decimator and the at least one decimator comprises one decimator for the I component and one decimator for the Q component.", "[0014] In another embodiment, the DDC is downstream of the at least one decimator and the at least one decimator comprises only one decimator for the received signal.", "This second embodiment is advantageous because only a single decimator is required.", "In addition, since the decimator is upstream of the DDC, the operating frequency of the DDC is reduced.", "[0015] Preferably, the DDC is arranged to generate the in-phase component I by multiplying the received signal by a cosine function and to generate the quadrature component Q by multiplying the received signal by a sine function.", "[0016] Preferably, the DDC operates at a frequency which is a predetermined number of times greater than the frequency of the received signal.", "In one embodiment, the DDC is arranged to operate at a frequency that is four times the frequency of the received signal, in which case the cosine function is simplified to the values {1, 0, −1, 0} over each cycle of the received signal and the sine function is simplified to the values {0, 1, 0, −1} over each cycle of the received signal.", "This allows the structure of the DDC to be simplified.", "Other simplifications could also be envisaged, for example if the operating frequency of the DDC were twice the frequency of the received signal.", "[0017] In one arrangement, the or each of the at least one decimator comprises a cascaded integrator comb (CIC) filter.", "A CIC filter is advantageous for performing decimation since it does not include multipliers.", "[0018] Preferably, the CIC filter comprises N integrator stages, N comb stages and a downsampler for reducing the sampling rate of the received signal.", "The down sampler may reduce the sampling rate by a factor of R. Each comb stage may introduce a delay of M to the CIC filter.", "The CIC filter may have the frequency response: H ⁡ ( ω ) = ( 1 - ⅇ - ⅈ ⁢ ⁢ RM ⁢ ⁢ ω ) N ( 1 - z - ⅈ ⁢ ⁢ ω ) N where ω is the frequency of the received signal.", "[0019] In another arrangement, the or each of the at least one decimator is a finite impulse response (FIR) filter.", "[0020] In one preferred embodiment, the or each of the at least one filter is arranged to perform pulse shaping of the received signal.", "[0021] In that embodiment, the or each of the at least one filter may comprise all or part of a raised cosine filter.", "[0022] In one case, the or each of the at least one filter may comprise a root raised cosine (RRC) filter.", "In that case, there will usually be at least one other RRC filter in the transmitter which transmitted the signals.", "The at least one RRC filter in the receiver together with the at least one RRC filter in the transmitter together provide raised cosine function pulse shaping of the signal.", "The or each RRC filter may comprise 49 taps.", "[0023] In an alternative embodiment, the or each of the at least one filter may comprise a low pass filter.", "[0024] The differential decoder may be arranged to perform differential detection of I and Q over a symbol span of one symbol.", "Of course, other symbol spans can also be envisaged.", "[0025] In one embodiment, the differential decoder comprises a decision block for converting the differentially decoded I into an I output and for converting the differentially decoded Q into a Q output, the I output and the Q output each taking a value of either 0 or 1.", "[0026] In that embodiment, the I decision may be: if the differentially decoded I is greater than zero, the I output is 0 and, if the differentially decoded I is less than zero, the I output is 1.", "In that embodiment, the Q decision may be: if the differentially decoded Q is greater than zero, the Q output is 0 and, if the differentially decoded Q is less than zero, the Q output is 1.", "[0027] In one embodiment, the apparatus further comprises a hard limiter for hard limiting the received DPSK signal.", "[0028] Preferably, the received signal is an intermediate frequency (IF) signal.", "Alternatively, the received signal may be a baseband signal.", "[0029] In one embodiment, the received signal is π 4 ⁢ DQPSK modulated.", "[0030] According to the invention, there is also provided a receiver for DPSK signals, the receiver comprising apparatus as described above.", "[0031] According to the invention, there is also provided a method for demodulating a received hard limited DPSK signal, the method comprising the steps of: [0032] a) generating an in-phase component I and a quadrature component Q from a received signal;", "[0033] b) reducing sampling frequency of the received signal;", "[0034] c) reducing noise outside a required bandwidth;", "and [0035] d) performing differential detection of I and Q over a given symbol span.", "[0036] In a first embodiment, step a) is performed before step b) and step b) comprises the steps of reducing sampling frequency of the in-phase component I and reducing sampling frequency of the quadrature component Q. [0037] In a second embodiment, step a) is performed after step b).", "The second embodiment is advantageous because only a single decimating step is required for the entire received signal rather than separate decimating steps for I and for Q. [0038] Preferably, step a) comprises multiplying the received signal by a cosine function to generate the in-phase component I and multiplying the received signal by a sine function to generate the quadrature component Q. [0039] Step a) of the method may be performed in a digital down converter (DDC).", "[0040] Step b) of the method may be performed in a cascaded integrator comb (CIC) filter.", "A CIC filter is advantageous for performing decimation since it does not includes multipliers.", "Preferably, the CIC filter comprises N integrator stages, N comb stages and a down sampler for reducing the sampling rate.", "The down sampler may reduce the sampling rate by a factor of R. Each comb stage may introduce a time delay of M to the CIC filter.", "[0041] Alternatively, step b) of the method may be performed in a single finite impulse response (FIR) filter.", "[0042] Step c) of the method may be performed in a low pass filter.", "[0043] In one embodiment, the method further comprises the step of pulse shaping the received signal.", "[0044] In that embodiment, in a first case, the step of reducing noise outside the required bandwidth and the step of pulse shaping the received signal may both be performed in a raised cosine filter.", "[0045] Alternatively, in a second case, the step of reducing noise outside the required bandwidth and the step of pulse shaping the received signal may be performed in a root raised cosine (RRC) filter.", "In the second case, there will usually be at least one other RRC filter in a transmitter which transmitted the signals.", "[0046] Step d) may comprise performing differential detection of I and Q over a symbol span of one symbol.", "[0047] The method may further comprise the steps of converting the differentially decoded I into an I output and converting the differentially decoded Q into a Q output, the I output and the Q output each taking a value of either 0 or 1.", "In that case, it may be set that, if the differentially decoded I is greater than zero, the I output is 0 and, if the differentially decoded I is less than zero, the I output is 1.", "Also, in that case, it may be set that, if the differentially decoded Q is greater than zero, the Q output is 0 and, if the differentially decoded Q is less than zero, the Q output is 1.", "[0048] In one embodiment, the method further comprises, before step a), the step of hard limiting the received DPSK signal.", "[0049] Preferably, the received signal is an intermediate frequency (IF) signal.", "Alternatively, the received signal may be a baseband signal.", "[0050] The received signal may be π 4 ⁢ DQPSK modulated.", "[0051] According to the invention there is also provided apparatus for carrying out the method described above.", "[0052] According to the invention there is also provided a receiver for DPSK signals, for carrying out the method described above.", "[0053] Features described in relation to the apparatus of the invention may also be applicable to the method of the invention and features described in relation to the method of the invention may also be applicable to the apparatus of the invention.", "BRIEF DESCRIPTION OF THE DRAWINGS [0054] By way of example, preferred embodiments of the invention will now be described with reference to the accompanying drawings, of which: [0055] FIG. 1 is a diagram of a demodulator according to a first embodiment of the invention;", "[0056] FIG. 2 is a detailed diagram of block 103 of FIG. 1 ;", "[0057] FIG. 3 is a detailed diagram of blocks 105 a and 105 b of FIG. 1 [0058] FIG. 4 is a detailed diagram of blocks 107 a and 107 b of FIG. 1 ;", "[0059] FIG. 5 is a graph showing performance of the demodulator of FIG. 1 at three different sampling rates;", "[0060] FIG. 6 is a diagram of a demodulator according to a second embodiment of the invention;", "[0061] FIG. 7 is a detailed diagram of block 605 of FIG. 6 ;", "[0062] FIG. 8 is a graph showing performance of the demodulators of FIGS. 1 and 6 ;", "and [0063] FIG. 9 is a diagram of a demodulator according to a third embodiment of the invention.", "DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0064] All the described embodiments show demodulators for π 4 ⁢ DQPSK , but the invention is not limited to π 4 ⁢ DQPSK and could apply to any differentially encoded PSK signal.", "Also, for all three described demodulators, the input is a 2-level (i.e. 1 bit) IF signal from an IF hard limiter.", "However, although the major application of the invention is IF signals, the invention could also be used with baseband.", "[0065] FIG. 1 shows a block diagram of a π 4 ⁢ DQPSK demodulator 101 according to a first embodiment of the invention.", "The demodulator includes a Digital Down Converter (DDC) 103 , Cascaded Integrator Comb (CIC) filters 105 a and 105 b , Root Raised Cosine (RRC) filters 107 a and 107 b , a differential decoder 109 and a decision block 111 .", "The input to the demodulator 101 is a 2-level (i.e. 1 bit) IF signal from an IF hard limiter (not shown).", "The outputs of the demodulator 101 are I and Q signals.", "[0066] FIG. 2 shows the DDC 103 of FIG. 1 in more detail.", "Digital down conversion is used to recover the in-phase component I and the quadrature component Q from the received IF signal.", "The IF signal can be expressed as: S k =A k cos{2π f IF kT s +φ k } where k is the sample number (also known as the order), A k is amplitude of the sampled IF signal at sample k, f IF is the intermediate frequency, T s is the time between one sample and the next i.e. the sampling interval and φ k is the phase of the sampled IF signal at sample k. [0067] T s (which is equal to 1 f s , f s being the sampling frequency) is chosen so that f s is as low as possible to still obtain acceptable performance in the demodulator given f IF .", "We can obtain acceptable performance with this arrangement with a sampling frequency f s much lower than the sampling frequency in known arrangements which use a hard limiter to digitize the incoming signal, as discussed previously.", "This is because, by sacrificing some of the reduced complexity of known hard limiter arrangements, we can obtain a huge decrease in required sampling rate.", "[0068] As shown in FIG. 2 , the I channel is formed by multiplying S k by cos{2πf IF kT s } at block 201 and the Q channel is formed by multiplying S k by sin{2πf IF kT s } at block 203 .", "The resulting I and Q components therefore have the form: I k =A k cos{2 πf IF kT s +φ k }cos{2 πf IF kT s } and Q k =A k cos{2 πf IF kT s +φ k }sin{2 πf IF kT s } [0069] FIG. 3 shows each CIC filter 105 a , 105 b of FIG. 1 in more detail.", "The CIC filters are used to perform decimation.", "A CIC filter is very efficient for performing decimation (or interpolation) since it does not contain multipliers.", "[0070] As shown in FIG. 3 , each CIC filter 105 a , 105 b comprises an integrator portion 301 and a comb portion 303 .", "Between the integrator portion 301 and the comb portion 303 there is a down sampler 305 for reducing the sampling rate by a factor R. The integrator portion comprises N integrator stages 307 clocked at rate f s = 1 T s .", "As is well known, each integrator stage is simply an infinite impulse response (IIR) filter which acts like a low pass filter.", "The comb portion comprises N comb stages 309 clocked at rate f s R = 1 RT s .", "Similarly, each comb stage is simply a finite impulse response (FIR) filter which acts like a high pass filter.", "[0071] The CIC filter may have the frequency response: H ⁡ ( ω ) = ( 1 - ⅇ - ⅈ ⁢ ⁢ RM ⁢ ⁢ ω ) N ( 1 - ⅇ - ⅈω ) N where ω is the frequency of the received signal and M is the time delay at each comb stage of the CIC filter.", "[0072] To reduce the power consumption of the subsequent RRC filter 107 , the higher the decimation rate of the CIC filter 105 , the better.", "However, greater decimation obviously means some degradation in performance.", "Thus, a compromise must be found between low sampling rate in the RRC and good BER performance of the demodulator.", "So, we choose R, M and N appropriately for the required frequency response of the CIC filter.", "[0073] FIG. 4 shows each RRC filter 107 a , 107 b of FIG. 1 in more detail.", "In this embodiment, RRC filters are used in the receiver since there will also be RRC filters (not shown) in the transmitter, meaning that the overall pulse shaping follows the raised cosine function (since the overall effect of the two filters is the product of the two functions).", "Alternatively, if there were no RRC filters in the transmitter, we could incorporate raised cosine filters in FIG. 1 instead of RRC filters.", "[0074] In any case, the purpose of the RRC filters is to perform pulse shaping to reduce the bandwidth of the over sampled symbol stream without introducing inter symbol interference and also to reduce noise outside the required bandwidth.", "[0075] Referring to FIG. 4 , each RRC filter 107 a , 107 b comprises 49 taps 401 in succession.", "Any number of taps could be chosen for the RRC filter (as long as the filter's frequency response meets the system requirements) but we prefer an odd number of taps so that the centre of the filter's impulse response will be a peak (rather than two equal values).", "Also, the greater the number of taps, the more attenuation there will be outside the desired bandwidth, but the greater the filter complexity and delay.", "[0076] Referring once again to FIG. 1 , after the RRC filters 107 a and 107 b , the I and Q signals are input into the differential decoder 109 .", "The differential decoder comprises buffers 113 a and 113 b , multipliers 115 a , 115 b , 115 c and 115 d and adders 117 a and 117 b .", "The differential decoder 109 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0077] This can be seen clearly from block 109 in FIG. 1 .", "The I in (k) signal is input into buffer 113 a , multiplier 115 a and multiplier 115 c .", "The Q in (k) signal is input into buffer 113 b , multiplier 115 b and multiplier 115 d .", "The buffer 113 a outputs the I signal from the previous sample i.e. I in (k−1) and stores the I in (k) signal for the next iteration.", "Similarly, the buffer 113 b outputs the Q signal from the previous sample i.e. Q in (k−1) and stores the Q in (k) signal for the next iteration.", "The output of multiplier 115 a is I(k)*I(k−1), the output of the multiplier 115 b is Q(k)*I(k−1), the output of multiplier 115 c is I(k)*Q(k−1) and the output of multiplier 115 d is Q(k)*Q(k−1).", "The outputs from multipliers 115 a and 115 d are input into adder 117 a producing I(k)I(k−1)+Q(k)Q(k−1) i.e. I out (k).", "The outputs from multipliers 115 b and 115 c are input into adder 117 b producing Q(k)I(k−1)−I(k)Q(k−1) i.e. Q out (k).", "[0078] After the differential decoder 109 , the I and Q signals are input into the decision block 111 .", "The decision rule might be something like [0000] if I out >0, I=0 else I=1 [0000] If Q out >0, Q=0 else Q=1 [0000] or any other suitable decision algorithm.", "[0079] FIG. 5 shows performance of the demodulator of FIG. 1 under three different test conditions.", "In all three cases, the symbol rate was 2.048 Mbps, the intermediate frequency f IF was 8.192 MHz and the CIC filter comprised two stages, with a decimation rate of R=4 (i.e. the decoding rate was always ¼ of the sampling rate).", "FIG. 5 is a plot of Eb No expressed in dB on the x-axis versus bit error ratio (BER) on the y-axis.", "Eb is the energy in one bit and No is the noise power in a 1 Hz bandwidth.", "So the numerical ratio Eb No is a form of signal to noise ratio.", "Thus, in FIG. 5 , the BER is shown as a function of Eb No i.e. in terms of the probability of error.", "[0080] In graph A, the sampling rate f s was 131.072 MHz (i.e. 16 times the intermediate frequency) and the decoding rate was 32.768 MHz.", "In graph B, the sampling rate f s was 262.144 MHz (i.e. 32 times the intermediate frequency) and the decoding rate was 65.536 MHz.", "In graph C, the sampling rate f s was 524.288 MHz (i.e. 64 times the intermediate frequency) and the decoding rate was 131.072 MHz.", "FIG. 5 also shows the theoretical result—graph D. [0081] It can be seen from FIG. 5 that the BER performance is better than that of prior art systems.", "In particular, this embodiment shows an improvement of 1.5 dB at a BER of 10 −4 over the system described in “Digital Intermediate Frequency Demodulation Technique for Cellular Communication Systems”, Hideho TOMITA, Yukio YOKOYAMA, Toru MATSUKI, Global Telecommunications Conference, 1990, and Exhibition “Communications: Connecting the Future”, GLOBECOM '90, IEEE, which was mentioned earlier.", "In addition, the sampling rate is lower: up to only 16 times the intermediate frequency as opposed to at least 32 times the intermediate frequency (and possibly as high as 100 times the intermediate frequency) in prior art systems.", "[0082] FIG. 6 shows a block diagram of a f s = 1 T s , demodulator 601 according to a second embodiment of the invention.", "The FIG. 6 arrangement is similar to the FIG. 1 arrangement and includes a CIC filter 603 , a DDC 605 , RRC filters 607 a and 607 b , a differential decoder 609 and a decision block 611 .", "As with FIG. 1 , the input to the demodulator 601 is the 2-level IF signal from an IF hard limiter (not shown) and the outputs of the demodulator 601 are I and Q signals.", "[0083] The FIG. 6 arrangement differs from the FIG. 1 arrangement in that the CIC filter 603 is upstream of the DDC 605 .", "There are several advantages in swapping the positions of the CIC filter(s) and the DDC which will be discussed below.", "[0084] The CIC filter 603 has a structure just like that shown in FIG. 3 .", "There is an integrator portion comprising N integrator stages clocked at rate π 4 ⁢ DQPSK followed by a down sampler for reducing the clock rate by a factor R, followed by a comb portion comprising N comb stages clocked at rate f s R = 1 RT s .", "Once again, we choose R, M and N appropriately depending on the required frequency response of the CIC filter.", "[0085] Obviously, with the arrangement of FIG. 6 , only a single CIC filter is required since the I and Q signals have not yet been isolated;", "this is one advantage of the FIG. 6 arrangement.", "Also, the CIC filter can be greatly simplified as explained below.", "[0086] In a CIC filter, the bit width growth is very fast.", "The output bit width can be shown to be: B out =┌N log 2 RM+B in ┐ where B in is the input bit width, B out is the output bit width, N is the number of CIC filter stages, R is the decimation ratio (i.e. the reduction of sampling rate as performed in the downsampler 305 ) and M is the delay in each comb unit.", "Therefore, the adders could have a rather large bit width.", "Moreover the B out bits are needed for every adder.", "[0087] In order to compare the FIG. 1 and FIG. 6 arrangements fairly, we set R=8 for the FIG. 1 arrangement and R=4 for the FIG. 6 arrangement.", "For both arrangements, we assume that N=2 and M=1.", "For the arrangement of FIG. 1 , the input to the CIC is the output of the DDC, which must be at least 4 bits to ensure acceptable performance in the DDC.", "Thus, for N=2, R=8, M=1 and B in =4, B out is 10.", "On the other hand, for the arrangement of FIG. 6 , the input to the CIC is the output of the hard limiter which is just 1 bit.", "So, for N=2, R=4, M=1 and B in =1, B out is only 5.", "Thus, the output bit width can be reduced with the FIG. 6 arrangement, which is clearly advantageous.", "[0088] Referring once again to FIG. 6 , from the CIC filter 603 , the signal is input to DDC 605 .", "In the FIG. 6 arrangement, the clock rate of the DDC can be reduced since the CIC filter has already performed decimation;", "this is advantageous since it reduces power consumption.", "So, whereas previously the DDC clock rate was f s , the DDC clock rate can now be 4 ⁢ Rf IF R = 4 ⁢ f IF .", "Also, if we set the sampling frequency f s appropriately, the DDC structure can be simplified as will now be explained.", "[0089] If we set the sampling frequency f s in the CIC to be 4Rf IF , the sampling rate in the DDC is f s R .", "Considering the DDC structure shown in FIG. 2 , we see that the I channel is produced by multiplying the incoming signal by cos{2πf IF kT s } and the Q channel is produced by multiplying the incoming signal by sin{2πf IF kT s }.", "However, since the DDC rate is four times that of the intermediate frequency, we can simplify the cosine and sine functions.", "This is because, over one cycle, cos x takes the values 1, 0, −1 and 0 and sin x takes the values 0, 1, 0 and −1.", "We can make use of this to simplify the DDC as shown in FIG. 7 .", "[0090] Referring to FIG. 7 , the incoming signal S k is multiplied by 1, 0, −1 and 0 at successive samples at block 701 to produce the I channel.", "The resulting I components are therefore of the forms: [0000] I k =S k ,0,−S k ,0 over a single cycle of the IF signal.", "[0091] The incoming signal S k is multiplied by 0, 1, 0 and −1 at successive samples at block 703 to produce the Q channel.", "The resulting Q components are therefore of the forms: [0000] Q k =0,S k ,0,−S k over a single cycle of the intermediate frequency signal.", "[0092] (We may be able to make a similar simplification to the DDC in the FIG. 1 arrangement.", "However, this is less likely since the clock rate of the DDC in that arrangement has to be f s (because the DDC comes before the CIC filter) and it is unlikely that we can obtain acceptable performance with a sampling frequency only four times the intermediate frequency.) [0093] Referring once again to FIG. 6 , the I and Q signals are then input to RRC filters 607 a and 607 b respectively.", "The RRC filters are used for pulse shaping the symbol stream without the introduction of inter symbol interference and also for reduction of noise outside the desired bandwidth and each RRC filter may have the structure shown in FIG. 4 .", "[0094] From RRC filter 607 a the I signal is input to the differential decoder 609 and from RRC filter 607 b , the Q signal is input to the differential decoder 609 .", "As before, the differential decoder comprises buffers 613 a and 613 b , multipliers 615 a , 615 b , 615 c and 615 d and adders 617 a and 617 b .", "The differential decoder 609 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0095] After the differential decoder 609 , the I and Q signals are input into the decision block 611 , which produces I and Q outputs from the differentially decoded I and Q. [0096] (In the FIG. 6 arrangement, we moved the CIC filter upstream of the DDC which brought several advantages.", "It would be possible to also bring the RRC upstream of the DDC.", "However, this arrangement will result in a complex filter before the DDC and the complexity of this complex filter is usually higher than the complexity of the two RRC filters.", "Also, to reject the out-of-band noise and higher frequency components of the DDC output, some kind of low pass filter may still be required after the DDC, even if a complex filter is used before the DDC.", "Therefore, although possible, this arrangement may not provide any additional advantages.) [0097] FIG. 8 shows performance of the demodulator of FIG. 1 and performance of the demodulator of FIG. 6 for a symbol rate of 2.048 Mbps, an intermediate frequency f IF of 8.192 MHz and a sampling rate of 131.072 MHz (i.e. 16 times the intermediate frequency).", "Like FIG. 5 , FIG. 8 is a plot of Eb No expressed in dB on the x-axis versus bit error ratio (BER) on the y-axis.", "As before, for a fair comparison of the FIG. 1 and FIG. 6 arrangements, we set the decimation rate R to be 8 for the FIG. 1 arrangement (plot E) and we set the decimation rate R to be 4 for the FIG. 6 arrangement (plot F).", "Once again, the theoretical result D is shown for comparison.", "[0098] It can be seen that the two embodiments (shown in FIGS. 1 and 6 ) produce almost exactly the same results.", "So, for both these embodiments, the BER performance shows an improvement over prior art BER performance and the sampling rate is lower.", "[0099] FIG. 9 shows a block diagram of a π 4 ⁢ DQPSK demodulator 901 according to a third embodiment of the invention.", "The FIG. 9 arrangement is similar to that of FIG. 6 but the CIC filter 603 has been replaced by a generic decimation filter 903 and the RRC filters 607 a and 607 b have been replaced by simple low pass filters (LPF) 907 a and 907 b .", "Thus, the arrangement includes a Decimation Filter (DF) 903 , a DDC 905 , LPFs 907 a and 907 b , a differential decoder 909 and a decision block 911 .", "As with FIGS. 1 and 6 , the input to the demodulator 901 is the 2-level IF signal from an IF hard limiter (not shown) and the outputs of the demodulator 901 are I and Q signals.", "[0100] The DF 903 is simply a general decimation filter for example a FIR filter.", "The purpose of the DF is to reduce the sampling rate.", "[0101] From the DF 903 , the signal is input to DDC 905 .", "The DDC structure may have the structure shown in FIG. 2 to produce I and Q channels by multiplication by cos{ 2πf IF kT s } and sin{2πf IF kT s }respectively.", "Or, the DDC structure could be simplified like DDC 605 in FIG. 6 .", "For example if the sampling rate of the DDC is four times the intermediate frequency, we can make use of the fact that the cosine function takes the values 1, 0, −1, 0 over each IF cycle and the sine function takes the values 0, 1, 0, −1 over each IF cycle.", "[0102] From the DDC 905 , the I and Q signals are input to the LPFs 907 a and 907 b .", "As already mentioned, the RRC filters in FIGS. 1 and 6 are used for pulse shaping and rejection of noise outside the required bandwidth.", "The pulse shaping was performed by the raised cosine function either by having RRC filter(s) in the transmitter side and RRC filter(s) in the receiver side, or by implementing the entire raised cosine function in the receiver side (i.e. doing no pulse shaping at all in the transmitter).", "If we now choose to do all the pulse shaping in the transmitter, we don't need to have even a RRC filter in the receiver.", "However, some kind of filter is still required to reduce noise outside the required bandwidth and interference, so we use simple low pass filters 907 a and 907 b .", "By performing all the pulse shaping on the transmitter side, the structure of the receiver can be simplified.", "[0103] From LPF 907 a , the I signal is input to the differential decoder 909 and from LPF 907 b , the Q signal is input to the differential decoder 909 .", "As before, the differential decoder comprises buffers 913 a and 913 b , multipliers 915 a , 915 b , 915 c and 915 d and adders 917 a and 917 b .", "The differential decoder 909 performs differential decoding of the incoming I and Q signals over a symbol span of one symbol, as follows: I out ( k )= I in ( k )* I in ( k− 1)+ Q in ( k )* Q in ( k− 1) Q out ( k )= Q in ( k )* I in ( k− 1)− I in ( k )* Q in ( k− 1) [0104] After the differential decoder 909 , the I and Q signals are input into the decision block 911 .", "[0105] Thus, in all the described embodiments, there is a lower power consumption because of the lower required sampling rate.", "Also, the performance in terms of BER is improved over prior art demodulators as shown in FIGS. 5 and 8 ." ]
This application is a continuation of application Ser. No. 08/505,599 filed Jul. 21, 1995, now abandoned, which was a continuation of application Ser. No. 08/120,721 filed Sep. 13, 1993, now abandoned. FIELD OF THE INVENTION The present invention relates generally to electrical connectors and more particularly concerns electrical connector assemblies with wadded wire contacts, recessed in apertures in an interface module, for the transmission of electric current between male pins touching the wadded wire contact on opposite sides. BACKGROUND OF THE INVENTION Electronic assemblies generally require multiple electrical connections such that electrical signals and current can flow from either a power source or a component with electrical signals to other components of the assembly via wires and cables. In those electronic assemblies, and particularly those used in the air transportation industry, durable and reliable connections must be made between the electrical components in order to properly transmit electrical signals and current. Many different types of electrical connectors have been used or proposed in the prior art. A common type of electrical connector is the pin and socket connector. Unfortunately, the pin and socket connector has been shown to have certain disadvantages. The pin and socket connector lacks the ability to provide efficient and reliable transmission of signals. Specifically, auxiliary contact area between the male and female contacts is critical to insure that a reliable connection is sustained in all conditions. For example, under conditions of vibration, as is typical in the air transportation industry, the need for a large contact area between the male and female contacts is essential. If contact is lost along one point of the contact area due to vibration, the auxiliary contact area assures the existence of contact at other points of the contact area. In addition, the possible presence of impurities in the contact area accumulated either during the manufacturing process or from environmental exposure also compels the designer to increase the contact area to prevent an interruption in the flow of signals or current. The risk of improperly mating the assemblies generated by defects in the manufacturing process or by the deformation of the parts after frequent engagement and disengagement further aggravates the problem. Thus, a substantial surface area of contact is essential to maintain an uninterrupted flow of electrical signals or current through the connector. Consequently, this enlarged contact surface area decreases the degree of design flexibility for the connectors. For instance, the number of connections that can be made through one connector assembly is severely limited. The greater space required by one connection leaves less room for other connections. Furthermore, if a specific number of connections are required for one connector assembly, then the size of the housing must be increased to accommodate the size of the surface area of the male and female members. When the size of individual connections is increased, the weight of the connector assembly is increased correspondingly. Further, more connector assemblies are needed to effectuate the requisite number of connections due to the fewer number of connections that can be made on each electrical connector assembly. Thus, because each individual connection has increased weight and further because more connector assemblies are needed to complete the necessary connections for the system, the total weight of the connector assemblies in a system is increased. Naturally, weight is a significant concern in most industries and particularly in the air transportation industry. A related disadvantage is that a comparatively high force is required to engage and disengage the connector assemblies. The engagement force is a function of the surface area of contact and the friction between the male and female contacts which, in turn, is a function of the tightness of the fit between those contacts. As previously noted, the surface area of contact must be sufficiently large to avoid any potential break in the continuity of the electrical connection. Furthermore, the frictional force between the contacts is generally high as well to ensure a stable connection. Hence, the person coupling the connector assemblies must apply a significant force to engage the electrical contacts. Likewise, disengagement demands a significant force. The necessary insertion and disengagement forces are increased with multiple contacts by each additional electrical connection maintained through the connector assembly. Furthermore, partially due to the necessary insertion force, the male pins can become bent if inserted erroneously. Subsequent insertion of the male pins into the female sockets is consequently inhibited. Another disadvantage is that the pins and sockets have relatively high electrical resistance. SUMMARY OF THE INVENTION It is the primary aim of the present invention to provide an electrical connector of decreased size and reduced weight while improving the integrity, durability and reliability of the electrical connection. Accordingly, providing environmental sealing from humidity and dust is a related object. Another related object is to provide means for the electrical connector to withstand vibration, particularly of the type common in aircraft. Reducing the engagement and disengagement forces is another important objective. A related object of the invention is to provide guidance for the insertion of the pins. An additional object is to facilitate the manufacture and assembly of the connector, particularly with regard to the insertion of the contact into the interface module. Protecting the contact from wear and deformation is an additional objective. Another object of the invention is to provide flexibility in the use of parts, but at the same time, prevent the mating of non-compatible connectors with the improved connector. A further object is to utilize existing wiring grommets, contact rear release clip retention systems and pin contact retention features currently defined and proven in U.S. government specifications, including but not limited to MIL-C-83723, MIL-C-38999 and MIL-C-39029. An additional object of the invention is to utilize standard wire crimping tools and insertion/removal tools, including but not limited to, the tools specified in U.S. government specification MIL-C-39029. Other objects and advantages of the present invention and its details of construction will be apparent from a consideration of the following specification and accompanying drawings. In accordance with the present invention, an improved electrical connector assembly is provided for linking an electrical line to another electrical line. The aforementioned objects are attained through the utilization of a resiliently compressible conductive contact recessed in the aperture of an interface module. The contact provides a means across which electric signals and current can flow from one male pin to another male pin without placing the pins into direct contact. The connector assembly includes at least one contact retained within the aperture of an interface or contact module. The interface or contact module is attached to a retainment component with one or more openings therethrough at positions corresponding to the opening in the interface module. That retainment component is situated inside a shell connectable to a second shell. An advantageous feature of this electrical connector and particularly the interface module is the reduction in diameter of the opening in the interface module from one end to the other end. The reduced diameter at the end of the opening which is exposed during use retains the contact within the interface module. In addition, assembly of the contact into the interface module is facilitated by the enlarged diameter in the opposite end of the opening in the interface module. The contact is held in place after the interface module is attached to the retainment component. Thus, the contact is trapped in the interface module. In addition, the junction between the retainment element and the interface module is sealed from environmental exposure by a protrusion around each opening in the retainment component that engages each opening in the interface module. Further, to assure that the male pins contact the ends of the contact accurately, the connector assemblies use a "bottoming" design. The connector assemblies are designed to always connect with the shells of the assemblies directly contacting axially to ensure the same relative axial position of each connection. In other words, the connector assemblies are designed to invariably result with the assemblies in the same relative axial position. Utilizing a datum reference at the connection point between the connector assemblies further advances the accuracy of the connection. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference should now be had to the embodiments illustrated in greater detail in the accompanying drawings. FIG. 1 is a perspective view of the connector of this invention; FIG. 2 is a partial cross-sectional view along line 2--2 of the connector shown in FIG. 1; FIG. 3 is an exploded, perspective view of the connector; FIG. 4 is an enlarged partial view of FIG. 2; FIG. 5 is a cross-sectional view along line 5--5 of FIG. 2 showing the interface module; and, FIG. 6 is a cross-sectional view along line 6--6 of FIG. 2 showing the seal which mates with the interface module; While the invention will be described in connection with certain preferred embodiments, it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, FIG. 1 shows a perspective view of the preferred embodiment of the connector 10 of the present invention. The connector 10 comprises a receptacle 12 and a plug 14. As depicted in FIG. 1, the receptacle 12 is engaged with the plug 14. The receptacle 12 and plug 14 are designed to connect a group of wires 16, 18, 20, 22 which extend from the ends of the receptacle 12 and plug 14. In order to reduce the complexity of FIG. 1, only four of the wires are shown. However, in this embodiment, two sets of thirteen wires could be connected by the connector 10. Referring to FIG. 3, the receptacle 12 includes a coupling nut 28, receptacle shell 30, contact module 32, contact 34, retainment component 36, pins 38 and coupling nut attachment components 40. The plug 14 includes a plug shell 50, a face seal 52, retainment component 54 and pins 56. FIG. 2 provides a partial cross-sectional view through one of the openings in the electrical connector 10. The wires 16, 20, are crimped or otherwise connected to the pins 38, 56. The pins 38 and 56 are shown inserted through the complementary openings in the receptacle 12 and plug 14. The pins 38, 56 protrude slightly into the contact module 32 and communicate with a resiliently compressible conductive contact 34 on opposite sides. The shells 30, 50 can be made of metal, preferably aluminum, or a sturdy plastic material. The shells 30, 50 have threaded portions 60, 62 so that the shells 30, 50 can be attached to other components. In addition, the plug shell 50 has a threaded portion 64 which engages the interior threads of coupling nut 28. The coupling nut 28 is rotatably attached to the receptacle shell 30 by the coupling nut attachment components 40 which are known in the art of electrical connectors. Thus, the receptacle 12 is connected to the plug 14 by threading the coupling nut 28 onto the threaded portion 64 of the plug shell 50 until the coupling nut 28 is snug and the shells 30, 50 are "bottomed out". Of course, other coupling means which are known in the art of electrical connectors can be used to connect the shells, including but not limited to, bayonet coupling or lands and grooves coupling. The shells 30, 50 contain the retainment components 36 and 54. The retainment components 36 and 54 include openings for the insertion of the pins 38 and 56 and wires 16, 20. The retainment components 36 and 54 may be a singular integral construction or preferably are composed of different combinations of parts designed for adjacent affixation. In this particular embodiment, the retainment components 36, 54 are composed of several different parts. Furthermore, consistent with one of the advantageous features of this invention, the retainment component 36 for the receptacle 12 is identical to the retainment component 54 for the plug 14. Consequently, this feature greatly reduces the number of individual parts required for the connector 10. As shown in FIG. 3, the retainment component 36 is shown in the assembled state and the retainment component 54 is shown in the exploded state. Since both containment components 36, 54 are identical, only retainment component 54 will be described in detail. Referring to FIGS. 3 and 4, retainment component 54 includes a grommet 76, rear insert half 78, front insert half 80, insert retaining clip 82, and two positioning inserts 84. The retaining clip 82 is positioned in an opening 86 between the rear insert 78 and the front insert 80. The rear insert 78 and the front insert 80 are then attached to each other by adhesive or other suitable means. In order to properly align the apertures in the front and rear inserts 78, 80, two positioning inserts 84 are inserted into grooves 86 on the front and rear inserts 78, 80. The two positioning inserts 84 are then attached to the front and rear inserts by adhesive or other suitable means. After the front and rear inserts are attached to each other the retaining clip 82 is trapped between the front and rear inserts. At a later stage in the assembly process, the clip 82 in used to hold the pin 56 in a relatively fixed position. In order to complete the retainment component 54, the grommet 76 is attached by adhesive or other means to the opposite face of the rear insert 78. Thus, the front insert 80, rear insert 78, retaining clips 82 the positioning inserts 84 and the grommet 76 are assembled to form the retainment component 54. Each adjacent part should have the same number and configuration of openings for the retainment of the pins 36 and 54. Separation of the parts provides flexibility in the use of materials for the retainment components 36, 54. For example, the grommet 76 can be composed of a soft material to provide sealing with the shell. Specifically, the grommet 76 is made of a resilient elastomer. However, the front and rear inserts can be fabricated of a harder material in order to use positioning flanges as will be discussed later. Specifically, the front insert, rear insert and positioning inserts are made of rigid plastic. Other combinations of materials may additionally be employed without departing from the essence of the invention. Interposed between the receptacle 12 and plug 14 is the interface or contact module 32 which includes contacts 34. The interface or contact module 32 is a cylindrical wafer 96 with at least one opening or aperture 98 therethrough. The interface module 32 is made of a rigid plastic. The contact 34 can be formed from a strand of a fine conductive metal wire wadded together to form a nearly cylindrical button. The wadded wire contact 34 may be of the type marketed by the Cinch Connector Division of Labinal Components and Systems, Inc., of Elk Grove Village, Ill., under the trademark CIN::APSE. Similar suitable buttons are available from other commercial sources. Referring now to FIGS. 2, 3 and 4 the interface or contact module 32 includes at least one aperture 98 through its thickness, but typically there are a plurality of apertures. Each aperture is defined by electrically insulated material. The aperture 98 in the interface module 32 has several different interior portions and extends from a first face surface 100 of the interface module 32 to a second face surface 102. Referring to FIG. 4, the aperture 32 has a chamfered portion 104 extending from the first face surface 100. As will be discussed later, the chamfered portion 104 will be used in conjunction with the seal 52 to create an environmental seal for the connections. Moving to the left in FIG. 4, the next portion of the aperture 98 is a tapered or conical portion 106. Although the tapered portion 106 appears to be cylindrical in FIG. 4, the diameter of the aperture is greater at the left end of tapered portion 106 and gradually reduces in diameter at the right end of tapered portion 106. The diameter at the left end is slightly larger that the diameter of the contact 34. The diameter at the right end is slightly smaller than the diameter of the contact 34. This tapered portion 106 has several advantages. First, the tapered portion 106 facilitates the insertion of the contacts 34 into the aperture 98 because the diameter at the left end is larger than the contacts 34. Second, the tapered portion 106 prevents the contacts 34 from exiting the right end of the aperture 98 because the diameter at the right end is smaller than the diameter of the contacts 34. Consequently, as will be discussed later the tapered surface 106 allows the contacts 34 to be held in the apertures 98 without the risk of accidentally exiting the aperture 98. A third advantage is that the contact 34 loosely fits within aperture 98 and is free to slide within the aperture 98. This freedom of movement eliminates some of the problems associated with compressive engagement of the contacts in the apertures. Impairment in the degree of resiliency in the contact 34 caused by compressive engagement is prevented. Second, because the contact 34 may move when the pins 38 and 56 touch the contact 34, the centering of the contact 34 within the aperture 98 is not critical. Furthermore, the loose fit between the contact 34 and the aperture 98 removes potential variances in the compressive engagement of the multiple wire strand elements making up the contact end surface and removes the attendant unpredictability of the electrical resistance. Finally, moving further to the left in FIG. 4, the next portion of aperture 98 is a recessed cylindrical or stepped portion 108. The stepped portion 108 has a diameter which is larger than the tapered portion 106. In assembly, the insertion of the contacts 34 in the interface module 32 is facilitated by the larger diameter stepped portion 108. While depicted in the drawing as stepped, this recessed portion 108 can alternatively be chamfered to guide the insertion of the contact 34 into the aperture 98. In addition, as will be discussed later, this stepped portion 108 facilitates the assembly and alignment of the apertures of the interface module 32 to the retainment component 36. After the contact 34 is inserted into aperture 98, the interface module 32 is adhered or otherwise attached to the retainment component 36, or more specifically, the front insert half 80. The retainment component 36 preferably has at least one protrusion 114 which fits into the stepped portion 108. The inside diameter of this protrusion 114 is smaller than the diameter of the contact 34. Thus, while the contact 34 can be easily inserted into the aperture 98 of the interface module 32, the retainment component 36 prevents the contact 34 from exiting the aperture 98 after assembly. On the right side of the aperture 98, a reduced diameter area prevents the contact 34 from moving beyond the point where the diameter of aperture 98 is less than the diameter of the contact 34. Accordingly, the contact 34 is trapped in this aperture 98. Moreover, this entrapment is effectuated without any radial force exerted upon the contact 34. As noted earlier, the aperture 98 includes a chamfered portion 104. This chamfered portion 104 forms a slope which guides the pin 56 into the proper position for protrusion into contact 34 when the receptacle 12 and plug 14 are engaged. A malleable protrusion 118 on retainment component 54 engages the walls of the chamfered portion 104 of the interface module 32 to form a seal. This seal is in the nature of a "cork and bottle" and protects the area of electrical contact from the environment. It is to be appreciated that the protrusion 118 may be integral with retainment component 54 or be attached as a separate face seal 52. A separate face seal 52 offers added interchangeability in the parts. The face seal 52 is made of a resilient elastomer. The dimensioning of the retainment components 36, 54 of the connector assembly can intentionally be symmetric. Consequently, the retainment components 36, 54 can be used interchangeably with either the receptacle 12 or plug 14. Another advantageous feature is that the male pins 38 and 56 protrude into the contact 34 on opposite sides without overly compressing it. The pins 38 and 56 are designed with flange areas 124 and 126 which engage abutment recesses 128 and 130 in the retainment components 36, 54. In addition, the flange areas 124, 126 on the pins engage the retaining clips 82. During assembly, the pins 38, 56 are attached to the individual wires 16, 20. Then the pins 38, 56 are inserted into the apertures in the retainment components 36, 54 until the flange areas 124, 126 of the pins engage the abutment recesses 128, 130. As the pins 38, 56 are inserted into the apertures, the retaining clips 82 engage the flange areas 124, 126 and prevent the pins 38, 56 from being removed from the apertures. Consequently, the pins 38, 56 are held in a relatively fixed position. Therefore, when the receptacle 12 and plug 14 are engaged with each other, the pins 38 and 56 can be inserted sufficiently to contact and protrude slightly into the contact 34 as shown in FIG. 4, but the abutment recesses 128 and 130 will obstruct forward movement beyond this point by engaging the flanges 124 and 126. As can be seen, another advantageous feature of the invention is that the pin contacts and the retainment components are common to both the receptacle and the plug. Consequently, this connector eliminates the need for socket contacts and their associated retainment components. Furthermore, the connector uses standard wire crimping tools and insertion/removal tools, including but not limited to, the tools specified in U.S. government specification MIL-C-39029. FIGS. 3, 4, 5 and 6 illustrate another advantageous feature of this invention that aids in the prevention of axial compression on contact 34. The shells 30, 50 are designed to "bottom out" when connected in order to consistently be in the same exact axial relationship when connected. When the receptacle 12 and plug 14 are engaged to be connected, the plug 12 moves into the receptacle 14 until the shell 30 of the plug 12 directly contacts with the shell 50 of the receptacle 14. In conjunction with the positioning features discussed subsequently, this "bottoming" of the receptacle 12 and plug 14 ensures that the male pins 38 and 56 reliably touch the contact 34 and do so without excessive compression. The "bottoming out" can be performed by several means. For example, predetermined threading on the shells 30, 50 in conjunction with the use of keys 138 and notches 140 will assure that the connectors unite precisely. The keys 138 and notches 140 assure that the starting point of the coupling is always at the same location on the threading. FIGS. 5 and 6 illustrate the matching keys 138 and notches 140. In addition, the accuracy of the alignment of the openings between the receptacle 12 and the plug 14 will also be ensured by these keys 138 and notches 140. Axial alignment can alternatively be achieved by the utilization of flanges situated on the shells 30, 50 at predetermined positions. When the flanges are clipped, pinned or screwed together, the shells 30, 50 are consequently forced to meet in the same axial position. Thus, this invention provides for the conduction of an electrical signal or current from a male pin 38 through the contact 34 to the male pin 56 without undue axial compression of the contact 34. Furthermore, referring back to FIG. 2, in the manufacturing and assembly process, drawings with datums located at the point of attachment, plane 146, between the edges 147, 148 of the shells 30, 50 are utilized. As all measurements are taken from this datum point 146 where the "bottoming out" occurs, a large tolerance build-up in the critical axially positioning feature is prevented. Indeed, no tolerance build-up will exist at the point of contact and "bottoming" of the connector halves is accordingly assured. Further, when the receptacle 12 and plug 14 are engaged as shown in FIG. 4, the annular shelves 150 and 152 on the interior of shells 30, 50 are an accurate distance from each other. These shelves 150 and 152 axially position the retainment components 36 and 54 by contacting the flanges 154, 156 on the retainment components 36, 54. The accurate positioning of the retainment components 36, 54 will then accurately position the flanges 124, 126 on the pins. The flanges 124, 126 determine the axial position of the pins 38 and 56 with respect to the contact 34. The precise positioning of these components assure that the pins 38 and 56 touch the contact 34 without undue compression. While the annular shelves 150 and 152 obstruct the retainment components 36 and 54 from forward movement, a sealing material 157 is positioned between the interior of the shells 30, 50 and the retainment components 35 and 54 which functions as an adhesive and as a seal against the environment. The sealing material is a silicone-based adhesive. Additional advantageous features of this invention are the reduction in the frequency of bent pins and external contact with the pins and contacts. Referring to FIG. 4, the pins 38 in the receptacle 12 are not exposed and the contacts 34 are housed internally in the interface or contact module 32. Consequently, the pins 38 and contacts 34 are protected from external contact. Furthermore, in the plug 14, the pins 56 protrude slightly beyond the seal 52. Consequently, if the user misaligns the receptacle 12 and plug 14, it is unlikely that the user will bend the pins 56. It will be appreciated, of course, that the foregoing arrangement is also suitable for non-cylindrical connectors. For example, the receptacle, the plug, the retainment components and the interface module can be rectangular in cross-section.
An improved electrical connector for use in electronic assemblies to link electronic components in order to transmit electric signals or current. The connector includes a wafer interface connective construction with at least one resiliently compressible contact to provide a means across which electrical current can flow from one male pin to another male pin without placing the pins in direct contact with each other. The contact retains its form and resiliency through its non-compressive retainment within the aperture of the wafer interface connective construction. Engagement and disengagement of the connector is facilitated, yet reliability and conductivity are enhanced. Further, the size and weight of the connector is reduced, and the assembly of the connector is facilitated. In addition, the pin contacts and the retainment components for the pin contacts are common to both halves of the connector which eliminates the need for socket contacts and their associated components.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "This application is a continuation of application Ser.", "No. 08/505,599 filed Jul. 21, 1995, now abandoned, which was a continuation of application Ser.", "No. 08/120,721 filed Sep. 13, 1993, now abandoned.", "FIELD OF THE INVENTION The present invention relates generally to electrical connectors and more particularly concerns electrical connector assemblies with wadded wire contacts, recessed in apertures in an interface module, for the transmission of electric current between male pins touching the wadded wire contact on opposite sides.", "BACKGROUND OF THE INVENTION Electronic assemblies generally require multiple electrical connections such that electrical signals and current can flow from either a power source or a component with electrical signals to other components of the assembly via wires and cables.", "In those electronic assemblies, and particularly those used in the air transportation industry, durable and reliable connections must be made between the electrical components in order to properly transmit electrical signals and current.", "Many different types of electrical connectors have been used or proposed in the prior art.", "A common type of electrical connector is the pin and socket connector.", "Unfortunately, the pin and socket connector has been shown to have certain disadvantages.", "The pin and socket connector lacks the ability to provide efficient and reliable transmission of signals.", "Specifically, auxiliary contact area between the male and female contacts is critical to insure that a reliable connection is sustained in all conditions.", "For example, under conditions of vibration, as is typical in the air transportation industry, the need for a large contact area between the male and female contacts is essential.", "If contact is lost along one point of the contact area due to vibration, the auxiliary contact area assures the existence of contact at other points of the contact area.", "In addition, the possible presence of impurities in the contact area accumulated either during the manufacturing process or from environmental exposure also compels the designer to increase the contact area to prevent an interruption in the flow of signals or current.", "The risk of improperly mating the assemblies generated by defects in the manufacturing process or by the deformation of the parts after frequent engagement and disengagement further aggravates the problem.", "Thus, a substantial surface area of contact is essential to maintain an uninterrupted flow of electrical signals or current through the connector.", "Consequently, this enlarged contact surface area decreases the degree of design flexibility for the connectors.", "For instance, the number of connections that can be made through one connector assembly is severely limited.", "The greater space required by one connection leaves less room for other connections.", "Furthermore, if a specific number of connections are required for one connector assembly, then the size of the housing must be increased to accommodate the size of the surface area of the male and female members.", "When the size of individual connections is increased, the weight of the connector assembly is increased correspondingly.", "Further, more connector assemblies are needed to effectuate the requisite number of connections due to the fewer number of connections that can be made on each electrical connector assembly.", "Thus, because each individual connection has increased weight and further because more connector assemblies are needed to complete the necessary connections for the system, the total weight of the connector assemblies in a system is increased.", "Naturally, weight is a significant concern in most industries and particularly in the air transportation industry.", "A related disadvantage is that a comparatively high force is required to engage and disengage the connector assemblies.", "The engagement force is a function of the surface area of contact and the friction between the male and female contacts which, in turn, is a function of the tightness of the fit between those contacts.", "As previously noted, the surface area of contact must be sufficiently large to avoid any potential break in the continuity of the electrical connection.", "Furthermore, the frictional force between the contacts is generally high as well to ensure a stable connection.", "Hence, the person coupling the connector assemblies must apply a significant force to engage the electrical contacts.", "Likewise, disengagement demands a significant force.", "The necessary insertion and disengagement forces are increased with multiple contacts by each additional electrical connection maintained through the connector assembly.", "Furthermore, partially due to the necessary insertion force, the male pins can become bent if inserted erroneously.", "Subsequent insertion of the male pins into the female sockets is consequently inhibited.", "Another disadvantage is that the pins and sockets have relatively high electrical resistance.", "SUMMARY OF THE INVENTION It is the primary aim of the present invention to provide an electrical connector of decreased size and reduced weight while improving the integrity, durability and reliability of the electrical connection.", "Accordingly, providing environmental sealing from humidity and dust is a related object.", "Another related object is to provide means for the electrical connector to withstand vibration, particularly of the type common in aircraft.", "Reducing the engagement and disengagement forces is another important objective.", "A related object of the invention is to provide guidance for the insertion of the pins.", "An additional object is to facilitate the manufacture and assembly of the connector, particularly with regard to the insertion of the contact into the interface module.", "Protecting the contact from wear and deformation is an additional objective.", "Another object of the invention is to provide flexibility in the use of parts, but at the same time, prevent the mating of non-compatible connectors with the improved connector.", "A further object is to utilize existing wiring grommets, contact rear release clip retention systems and pin contact retention features currently defined and proven in U.S. government specifications, including but not limited to MIL-C-83723, MIL-C-38999 and MIL-C-39029.", "An additional object of the invention is to utilize standard wire crimping tools and insertion/removal tools, including but not limited to, the tools specified in U.S. government specification MIL-C-39029.", "Other objects and advantages of the present invention and its details of construction will be apparent from a consideration of the following specification and accompanying drawings.", "In accordance with the present invention, an improved electrical connector assembly is provided for linking an electrical line to another electrical line.", "The aforementioned objects are attained through the utilization of a resiliently compressible conductive contact recessed in the aperture of an interface module.", "The contact provides a means across which electric signals and current can flow from one male pin to another male pin without placing the pins into direct contact.", "The connector assembly includes at least one contact retained within the aperture of an interface or contact module.", "The interface or contact module is attached to a retainment component with one or more openings therethrough at positions corresponding to the opening in the interface module.", "That retainment component is situated inside a shell connectable to a second shell.", "An advantageous feature of this electrical connector and particularly the interface module is the reduction in diameter of the opening in the interface module from one end to the other end.", "The reduced diameter at the end of the opening which is exposed during use retains the contact within the interface module.", "In addition, assembly of the contact into the interface module is facilitated by the enlarged diameter in the opposite end of the opening in the interface module.", "The contact is held in place after the interface module is attached to the retainment component.", "Thus, the contact is trapped in the interface module.", "In addition, the junction between the retainment element and the interface module is sealed from environmental exposure by a protrusion around each opening in the retainment component that engages each opening in the interface module.", "Further, to assure that the male pins contact the ends of the contact accurately, the connector assemblies use a "bottoming"", "design.", "The connector assemblies are designed to always connect with the shells of the assemblies directly contacting axially to ensure the same relative axial position of each connection.", "In other words, the connector assemblies are designed to invariably result with the assemblies in the same relative axial position.", "Utilizing a datum reference at the connection point between the connector assemblies further advances the accuracy of the connection.", "BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of this invention, reference should now be had to the embodiments illustrated in greater detail in the accompanying drawings.", "FIG. 1 is a perspective view of the connector of this invention;", "FIG. 2 is a partial cross-sectional view along line 2--2 of the connector shown in FIG. 1;", "FIG. 3 is an exploded, perspective view of the connector;", "FIG. 4 is an enlarged partial view of FIG. 2;", "FIG. 5 is a cross-sectional view along line 5--5 of FIG. 2 showing the interface module;", "and, FIG. 6 is a cross-sectional view along line 6--6 of FIG. 2 showing the seal which mates with the interface module;", "While the invention will be described in connection with certain preferred embodiments, it is not intended to limit the invention to those embodiments.", "On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, FIG. 1 shows a perspective view of the preferred embodiment of the connector 10 of the present invention.", "The connector 10 comprises a receptacle 12 and a plug 14.", "As depicted in FIG. 1, the receptacle 12 is engaged with the plug 14.", "The receptacle 12 and plug 14 are designed to connect a group of wires 16, 18, 20, 22 which extend from the ends of the receptacle 12 and plug 14.", "In order to reduce the complexity of FIG. 1, only four of the wires are shown.", "However, in this embodiment, two sets of thirteen wires could be connected by the connector 10.", "Referring to FIG. 3, the receptacle 12 includes a coupling nut 28, receptacle shell 30, contact module 32, contact 34, retainment component 36, pins 38 and coupling nut attachment components 40.", "The plug 14 includes a plug shell 50, a face seal 52, retainment component 54 and pins 56.", "FIG. 2 provides a partial cross-sectional view through one of the openings in the electrical connector 10.", "The wires 16, 20, are crimped or otherwise connected to the pins 38, 56.", "The pins 38 and 56 are shown inserted through the complementary openings in the receptacle 12 and plug 14.", "The pins 38, 56 protrude slightly into the contact module 32 and communicate with a resiliently compressible conductive contact 34 on opposite sides.", "The shells 30, 50 can be made of metal, preferably aluminum, or a sturdy plastic material.", "The shells 30, 50 have threaded portions 60, 62 so that the shells 30, 50 can be attached to other components.", "In addition, the plug shell 50 has a threaded portion 64 which engages the interior threads of coupling nut 28.", "The coupling nut 28 is rotatably attached to the receptacle shell 30 by the coupling nut attachment components 40 which are known in the art of electrical connectors.", "Thus, the receptacle 12 is connected to the plug 14 by threading the coupling nut 28 onto the threaded portion 64 of the plug shell 50 until the coupling nut 28 is snug and the shells 30, 50 are "bottomed out".", "Of course, other coupling means which are known in the art of electrical connectors can be used to connect the shells, including but not limited to, bayonet coupling or lands and grooves coupling.", "The shells 30, 50 contain the retainment components 36 and 54.", "The retainment components 36 and 54 include openings for the insertion of the pins 38 and 56 and wires 16, 20.", "The retainment components 36 and 54 may be a singular integral construction or preferably are composed of different combinations of parts designed for adjacent affixation.", "In this particular embodiment, the retainment components 36, 54 are composed of several different parts.", "Furthermore, consistent with one of the advantageous features of this invention, the retainment component 36 for the receptacle 12 is identical to the retainment component 54 for the plug 14.", "Consequently, this feature greatly reduces the number of individual parts required for the connector 10.", "As shown in FIG. 3, the retainment component 36 is shown in the assembled state and the retainment component 54 is shown in the exploded state.", "Since both containment components 36, 54 are identical, only retainment component 54 will be described in detail.", "Referring to FIGS. 3 and 4, retainment component 54 includes a grommet 76, rear insert half 78, front insert half 80, insert retaining clip 82, and two positioning inserts 84.", "The retaining clip 82 is positioned in an opening 86 between the rear insert 78 and the front insert 80.", "The rear insert 78 and the front insert 80 are then attached to each other by adhesive or other suitable means.", "In order to properly align the apertures in the front and rear inserts 78, 80, two positioning inserts 84 are inserted into grooves 86 on the front and rear inserts 78, 80.", "The two positioning inserts 84 are then attached to the front and rear inserts by adhesive or other suitable means.", "After the front and rear inserts are attached to each other the retaining clip 82 is trapped between the front and rear inserts.", "At a later stage in the assembly process, the clip 82 in used to hold the pin 56 in a relatively fixed position.", "In order to complete the retainment component 54, the grommet 76 is attached by adhesive or other means to the opposite face of the rear insert 78.", "Thus, the front insert 80, rear insert 78, retaining clips 82 the positioning inserts 84 and the grommet 76 are assembled to form the retainment component 54.", "Each adjacent part should have the same number and configuration of openings for the retainment of the pins 36 and 54.", "Separation of the parts provides flexibility in the use of materials for the retainment components 36, 54.", "For example, the grommet 76 can be composed of a soft material to provide sealing with the shell.", "Specifically, the grommet 76 is made of a resilient elastomer.", "However, the front and rear inserts can be fabricated of a harder material in order to use positioning flanges as will be discussed later.", "Specifically, the front insert, rear insert and positioning inserts are made of rigid plastic.", "Other combinations of materials may additionally be employed without departing from the essence of the invention.", "Interposed between the receptacle 12 and plug 14 is the interface or contact module 32 which includes contacts 34.", "The interface or contact module 32 is a cylindrical wafer 96 with at least one opening or aperture 98 therethrough.", "The interface module 32 is made of a rigid plastic.", "The contact 34 can be formed from a strand of a fine conductive metal wire wadded together to form a nearly cylindrical button.", "The wadded wire contact 34 may be of the type marketed by the Cinch Connector Division of Labinal Components and Systems, Inc., of Elk Grove Village, Ill.", ", under the trademark CIN::APSE.", "Similar suitable buttons are available from other commercial sources.", "Referring now to FIGS. 2, 3 and 4 the interface or contact module 32 includes at least one aperture 98 through its thickness, but typically there are a plurality of apertures.", "Each aperture is defined by electrically insulated material.", "The aperture 98 in the interface module 32 has several different interior portions and extends from a first face surface 100 of the interface module 32 to a second face surface 102.", "Referring to FIG. 4, the aperture 32 has a chamfered portion 104 extending from the first face surface 100.", "As will be discussed later, the chamfered portion 104 will be used in conjunction with the seal 52 to create an environmental seal for the connections.", "Moving to the left in FIG. 4, the next portion of the aperture 98 is a tapered or conical portion 106.", "Although the tapered portion 106 appears to be cylindrical in FIG. 4, the diameter of the aperture is greater at the left end of tapered portion 106 and gradually reduces in diameter at the right end of tapered portion 106.", "The diameter at the left end is slightly larger that the diameter of the contact 34.", "The diameter at the right end is slightly smaller than the diameter of the contact 34.", "This tapered portion 106 has several advantages.", "First, the tapered portion 106 facilitates the insertion of the contacts 34 into the aperture 98 because the diameter at the left end is larger than the contacts 34.", "Second, the tapered portion 106 prevents the contacts 34 from exiting the right end of the aperture 98 because the diameter at the right end is smaller than the diameter of the contacts 34.", "Consequently, as will be discussed later the tapered surface 106 allows the contacts 34 to be held in the apertures 98 without the risk of accidentally exiting the aperture 98.", "A third advantage is that the contact 34 loosely fits within aperture 98 and is free to slide within the aperture 98.", "This freedom of movement eliminates some of the problems associated with compressive engagement of the contacts in the apertures.", "Impairment in the degree of resiliency in the contact 34 caused by compressive engagement is prevented.", "Second, because the contact 34 may move when the pins 38 and 56 touch the contact 34, the centering of the contact 34 within the aperture 98 is not critical.", "Furthermore, the loose fit between the contact 34 and the aperture 98 removes potential variances in the compressive engagement of the multiple wire strand elements making up the contact end surface and removes the attendant unpredictability of the electrical resistance.", "Finally, moving further to the left in FIG. 4, the next portion of aperture 98 is a recessed cylindrical or stepped portion 108.", "The stepped portion 108 has a diameter which is larger than the tapered portion 106.", "In assembly, the insertion of the contacts 34 in the interface module 32 is facilitated by the larger diameter stepped portion 108.", "While depicted in the drawing as stepped, this recessed portion 108 can alternatively be chamfered to guide the insertion of the contact 34 into the aperture 98.", "In addition, as will be discussed later, this stepped portion 108 facilitates the assembly and alignment of the apertures of the interface module 32 to the retainment component 36.", "After the contact 34 is inserted into aperture 98, the interface module 32 is adhered or otherwise attached to the retainment component 36, or more specifically, the front insert half 80.", "The retainment component 36 preferably has at least one protrusion 114 which fits into the stepped portion 108.", "The inside diameter of this protrusion 114 is smaller than the diameter of the contact 34.", "Thus, while the contact 34 can be easily inserted into the aperture 98 of the interface module 32, the retainment component 36 prevents the contact 34 from exiting the aperture 98 after assembly.", "On the right side of the aperture 98, a reduced diameter area prevents the contact 34 from moving beyond the point where the diameter of aperture 98 is less than the diameter of the contact 34.", "Accordingly, the contact 34 is trapped in this aperture 98.", "Moreover, this entrapment is effectuated without any radial force exerted upon the contact 34.", "As noted earlier, the aperture 98 includes a chamfered portion 104.", "This chamfered portion 104 forms a slope which guides the pin 56 into the proper position for protrusion into contact 34 when the receptacle 12 and plug 14 are engaged.", "A malleable protrusion 118 on retainment component 54 engages the walls of the chamfered portion 104 of the interface module 32 to form a seal.", "This seal is in the nature of a "cork and bottle"", "and protects the area of electrical contact from the environment.", "It is to be appreciated that the protrusion 118 may be integral with retainment component 54 or be attached as a separate face seal 52.", "A separate face seal 52 offers added interchangeability in the parts.", "The face seal 52 is made of a resilient elastomer.", "The dimensioning of the retainment components 36, 54 of the connector assembly can intentionally be symmetric.", "Consequently, the retainment components 36, 54 can be used interchangeably with either the receptacle 12 or plug 14.", "Another advantageous feature is that the male pins 38 and 56 protrude into the contact 34 on opposite sides without overly compressing it.", "The pins 38 and 56 are designed with flange areas 124 and 126 which engage abutment recesses 128 and 130 in the retainment components 36, 54.", "In addition, the flange areas 124, 126 on the pins engage the retaining clips 82.", "During assembly, the pins 38, 56 are attached to the individual wires 16, 20.", "Then the pins 38, 56 are inserted into the apertures in the retainment components 36, 54 until the flange areas 124, 126 of the pins engage the abutment recesses 128, 130.", "As the pins 38, 56 are inserted into the apertures, the retaining clips 82 engage the flange areas 124, 126 and prevent the pins 38, 56 from being removed from the apertures.", "Consequently, the pins 38, 56 are held in a relatively fixed position.", "Therefore, when the receptacle 12 and plug 14 are engaged with each other, the pins 38 and 56 can be inserted sufficiently to contact and protrude slightly into the contact 34 as shown in FIG. 4, but the abutment recesses 128 and 130 will obstruct forward movement beyond this point by engaging the flanges 124 and 126.", "As can be seen, another advantageous feature of the invention is that the pin contacts and the retainment components are common to both the receptacle and the plug.", "Consequently, this connector eliminates the need for socket contacts and their associated retainment components.", "Furthermore, the connector uses standard wire crimping tools and insertion/removal tools, including but not limited to, the tools specified in U.S. government specification MIL-C-39029.", "FIGS. 3, 4, 5 and 6 illustrate another advantageous feature of this invention that aids in the prevention of axial compression on contact 34.", "The shells 30, 50 are designed to "bottom out"", "when connected in order to consistently be in the same exact axial relationship when connected.", "When the receptacle 12 and plug 14 are engaged to be connected, the plug 12 moves into the receptacle 14 until the shell 30 of the plug 12 directly contacts with the shell 50 of the receptacle 14.", "In conjunction with the positioning features discussed subsequently, this "bottoming"", "of the receptacle 12 and plug 14 ensures that the male pins 38 and 56 reliably touch the contact 34 and do so without excessive compression.", "The "bottoming out"", "can be performed by several means.", "For example, predetermined threading on the shells 30, 50 in conjunction with the use of keys 138 and notches 140 will assure that the connectors unite precisely.", "The keys 138 and notches 140 assure that the starting point of the coupling is always at the same location on the threading.", "FIGS. 5 and 6 illustrate the matching keys 138 and notches 140.", "In addition, the accuracy of the alignment of the openings between the receptacle 12 and the plug 14 will also be ensured by these keys 138 and notches 140.", "Axial alignment can alternatively be achieved by the utilization of flanges situated on the shells 30, 50 at predetermined positions.", "When the flanges are clipped, pinned or screwed together, the shells 30, 50 are consequently forced to meet in the same axial position.", "Thus, this invention provides for the conduction of an electrical signal or current from a male pin 38 through the contact 34 to the male pin 56 without undue axial compression of the contact 34.", "Furthermore, referring back to FIG. 2, in the manufacturing and assembly process, drawings with datums located at the point of attachment, plane 146, between the edges 147, 148 of the shells 30, 50 are utilized.", "As all measurements are taken from this datum point 146 where the "bottoming out"", "occurs, a large tolerance build-up in the critical axially positioning feature is prevented.", "Indeed, no tolerance build-up will exist at the point of contact and "bottoming"", "of the connector halves is accordingly assured.", "Further, when the receptacle 12 and plug 14 are engaged as shown in FIG. 4, the annular shelves 150 and 152 on the interior of shells 30, 50 are an accurate distance from each other.", "These shelves 150 and 152 axially position the retainment components 36 and 54 by contacting the flanges 154, 156 on the retainment components 36, 54.", "The accurate positioning of the retainment components 36, 54 will then accurately position the flanges 124, 126 on the pins.", "The flanges 124, 126 determine the axial position of the pins 38 and 56 with respect to the contact 34.", "The precise positioning of these components assure that the pins 38 and 56 touch the contact 34 without undue compression.", "While the annular shelves 150 and 152 obstruct the retainment components 36 and 54 from forward movement, a sealing material 157 is positioned between the interior of the shells 30, 50 and the retainment components 35 and 54 which functions as an adhesive and as a seal against the environment.", "The sealing material is a silicone-based adhesive.", "Additional advantageous features of this invention are the reduction in the frequency of bent pins and external contact with the pins and contacts.", "Referring to FIG. 4, the pins 38 in the receptacle 12 are not exposed and the contacts 34 are housed internally in the interface or contact module 32.", "Consequently, the pins 38 and contacts 34 are protected from external contact.", "Furthermore, in the plug 14, the pins 56 protrude slightly beyond the seal 52.", "Consequently, if the user misaligns the receptacle 12 and plug 14, it is unlikely that the user will bend the pins 56.", "It will be appreciated, of course, that the foregoing arrangement is also suitable for non-cylindrical connectors.", "For example, the receptacle, the plug, the retainment components and the interface module can be rectangular in cross-section." ]
FIELD OF THE INVENTION [0001] This invention relates to mechanical control assemblies, and more particularly to push-pull or reciprocating cable assemblies suitable for aeronautical applications. BACKGROUND [0002] Push-pull control cable assemblies are used for many systems, e.g. aircraft engines, which must be adjusted from a distance or which are located in hostile environments. These controls frequently have a cable that reciprocates within a casing that supports and protects the cable. Fittings are typically attached to both ends of the cable to connect it to a system to be controlled at one end, and to operating levers, pedals and the like at the other end. [0003] With existing controls of this type, the entire control cable assembly must be removed for repair or replacement, and the cable itself cannot be thoroughly inspected without removal of fittings permanently attached to each end. When these cables fail, they are normally discarded and replaced. To facilitate inspection, repair and replacement, a control assembly with a reciprocating cable that can be removed from the casing without removing or disassembling the casing would be desirable. SUMMARY OF THE INVENTION [0004] This invention provides improved control cable assemblies having control cables mounted within and adapted for reciprocation within an outer casing. A fitting is permanently attached, preferable by swaging or other mechanical deformation process, to at least one end, normally both ends, of the control cable. These fittings have a projected width, i.e. the width in a plane at right angles to the axis of the cable, no greater than the inner diameter of the casing. As a result, the entire control cable, with fittings attached, can be pulled through the casing to remove the control cable for inspection, maintenance or replacement. This simplifies maintenance, and substantially increases the service life of the cable assembly. To facilitate connection to control levers, pedals or the like, or to apparatus to be controlled or operated, couplings or other connecting members may be detachably secured to the fittings by renewable connections such as threaded joints, for example, that allow the couplings to be removed and replaced easily. [0005] The invention also provides a unique combination of ball joint assemblies and excluder seals that effectively exclude contaminants from the interior of the casing, which also helps to increase service life. These and other features of the inventive cable are described more thoroughly in the following detailed description. DRAWINGS [0006] [0006]FIG. 1 is a fragmentary, partially cutaway plan view of a control cable assembly embodying this invention. [0007] [0007]FIG. 2 is a cross-sectional view along lines 2 - 2 in FIG. 1. [0008] [0008]FIG. 3 is an enlarged cross-sectional view of a ball joint assembly in the control cable assembly illustrated in FIGS. 1 and 2. [0009] [0009]FIG. 4 is a further enlarged cross-sectional view of an excluder seal in the control cable assembly of FIGS. 1 and 2. [0010] [0010]FIG. 5 is an end view of the excluder seal in FIG. 4, partially cut away to show parts of the excluder seal in more detail. DETAILED DESCRIPTION [0011] [0011]FIG. 1 illustrates a control cable assembly, generally referred to as 10 , embodying this invention. Cable assembly 10 may extend from the cockpit of an aircraft, or another operating area, to an engine compartment or other remote or hostile location. The cable assembly has a control cable 20 adapted for reciprocation within a casing 40 . Casing 40 typically extends through a bulkhead fitting 15 in a wall or other partition between the aircraft cockpit, or other operating area, and the compartment where the engine or other system to be controlled is located. [0012] Each end of control cable 20 has an end rod 28 with a threaded end 32 for attaching a connecting member, such as the couplings 38 illustrated in FIG. 1, that attach the end rods 28 to control levers, pedals or the like in an aircraft cabin or other operating compartment, or to an engine or other system to be controlled. The diameter of the end rods 28 is less than the inner diameter of the casing 40 . This allows the control cable 20 , with end rods attached, to be pulled through the casing 40 and removed for inspection, repair or replacement when a coupling 38 has been removed from one of the end rods. In most cases, both ends of the control cable 20 are substantially the same. Thus, the cable can normally be removed in either direction. However, there may be modifications for particular applications, such as differences in the threads on the end rods. [0013] The ability to remove control cable 20 from casing 40 permits servicing, maintenance and repairs that were not possible with prior art control cable assemblies, whose central cables could not be removed without removing end fittings that were permanently attached to this control cable by swaging or the like. This is not a problem with the control cables of this invention, however, because the end rods that are permanently attached to the cables can pulled through the casing. Typically, couplings 38 or other connecting members, designed for connections with engines or other systems to be operated or controlled, or to control levers, pedals or the like, are attached to the end rods with threaded or other renewable connections that allow the connecting members to be removed without distorting or damaging either the end rods or the connecting members. Thus, the control cable can be removed from the casing and the connecting members can be replaced or reinstalled when the control cable has been reinstalled or replaced. The ability to remove and reinstall or replace the control cable in this manner reduces the cost of maintaining and repairing the cable assembly 10 , and tends to increase its useable life. [0014] The central part of control cable 20 is similar to prior control systems of this sort. It consists of a flexible core 22 of stranded wire covered with an armor construction or cover formed by steel flats 24 wrapped around the stranded wire core 22 . The steel flats protect the stranded wire core from wear, crushing and the like, and support the core if it is placed in compression. As best seen in FIG. 2, the armor is peeled from or left off the end of the core, which is inserted into a cylindrical bore 34 in end rod 28 . The thin cylindrical shell 36 that surrounds bore 34 is then mechanically swaged or compressed to clamp end rod 28 to the bare core 22 on the end of the flexible cable with sufficient compression to maintain a secure connection between the end rod 28 and core 22 when the cable 20 is placed in tension. [0015] The central part of casing 40 is also similar to prior control cable assemblies. A stranded wire conduit 42 is wrapped with steel flats 44 that are similar to the flats 24 that form the armor cover on the core 22 . The stranded wire conduit 42 is lined with a polytetrafluoroethylene tube 46 that reduces friction on the control cable 20 . [0016] As shown in FIG. 2, casing 40 extends into cylindrical bores 52 in casing caps 48 , and the thin annular shells 54 that surround the cylindrical bores 52 are mechanically swaged to lock the casing caps securely on the casing assembly. Like the swaged connection between the end rod and the central core 22 , this connection provides a robust, dependable connection. The joints between the casing assembly 40 and the casing caps 48 are sealed with a watertight, two piece epoxy sealant to exclude foreign material at these joints. [0017] The ends of the cable 20 extend through support tubes 62 , mounted in ball joint housings 74 threaded onto casing caps 48 . As best seen in FIG. 2, the joints between the end rods 28 and cable 20 are preferably located in the central portions of the support tubes 62 . The end rods extend through excluder seal assemblies 110 , described in more detail below, attached to the outer ends of the support tubes. The control cables 20 extend through casing caps 48 into enlarged, substantially spherical knobs 66 at the inner ends of the support tubes 62 . These knobs 66 are enclosed within generally cylindrical ball joint housings 74 that allow the end rods to pivot through at an angle of at least 5 [0018] ° in any direction from the illustrated central position. In other words, the end rod can swivel within a cone having a central angle of 10° or more. As shown in FIG. 3, an inwardly extending shoulder 76 on each housing defines a hole 78 which is slightly larger than the section of the support tube extending through this hole. This allows the support tube and end rod to pivot within the specified limits, but prevents excessive movement which could damage the flexible core within the ball joint. As best seen in FIG. 3, the ends of control cable 20 enter the enlarged knobs on the support tubes through conical bores 68 , which typically have a cone angle roughly equal to the angle of the cone within which the support tubes can pivot. The sides of these conical bores help to support the control cable when the end rods pivot. [0019] As also shown in FIG. 3, the enlarged knobs 66 at the inner ends of the support tubes are sealed within ball joint housings 74 by pairs of polytetrafluoroethylene seals 92 , 96 . Springs 82 , held in place by retaining rings 84 mounted in grooves in the inner walls of the housings, press seals 92 against the spherical ends 66 of the support tubes. The spherical ends of the support tubes press against seals 96 , which are held in place by the inwardly extending shoulders 76 on the end of the housings 74 . Seals 92 and 96 protect the cable assembly from contamination along the surface of the of the support tubes 62 . O-rings 94 , 98 at the outer corners of seals 92 and 96 seal against the inner walls of the ball joint housings 74 and minimize the potential for contamination at these points. [0020] As mentioned above, each end rod 28 extends through an excluder seal assembly 110 , shown in FIG. 4 and 5 . The excluder seal assembly 110 has a U-cup rod seal 114 , commercially available from Shamban Seals, mounted in a nose cap 112 treaded onto the outer end of support tube 62 . Rod seal 114 is energized by a spring 116 which presses against the end of the support tube. The compressed spring 116 presses the U-cup rod seal against end rod 28 , providing a dependable seal at this juncture. [0021] The excluder seal assembly also incorporates a pair of knife-like conical brass wiper rings 122 , 132 , shown in FIGS. 4 and 5 and commercially available from Wynn's Precision, Inc, Houston, Texas, which act as blades to remove and dispose of foreign matter on the end rod 28 , thereby protecting the U-cup rod seals. Each of these rings has a flange 124 , 134 at its base or inner end. The wiper rings are held in place by a cushion ring 138 of an elastomeric materials such as nitrile, butyl, fluoroelastomers or PTFE. As shown in FIG. 5, each of the wiper rings 122 , 132 has a pair of slits or notches 126 , 136 , spaced 180° degrees apart in the conical wall and oriented so that the slits 126 in the inner wiper ring 122 are not aligned with the slits 136 in the outer wiper ring seal. These slits provide flexibility, allow for expansion, and produce a spring effect resulting in constant contact with the end rod 28 , full circle. When compressed, cushion ring 128 preloads the wiper rings for wiper edge contact with the end rods 28 , and absorb shock and side loads. The seal is self adjusting. The wiper rings lengthen the life of the U-cup seals by keeping foreign material from damaging the lips of the U-cup seals, and provide a secondary seal that further reduces the risk of contamination. [0022] The combination of the PTFE/o-ring seals in the ball joint assembly 60 and the spring energized U-cup rod seals and wiper rings in the excluder seal assembly 110 provide increased and dependable protection against contamination from foreign materials entering the cable, thus increasing the anticipated life of the cable assembly. As those skilled in the art will readily appreciate, the removable core assemblies of these inventive cables also facilitate servicing, maintenance and repairs, which increases the anticipated service life still further. Of course, as those skilled in the art will also appreciate, the control cable assembly shown and described herein is merely illustrative. Many modifications to and adaptations of the illustrated assembly may be made within the scope of this invention, which is defined by the following claims.
Reciprocating or push-pull control cable assemblies have fittings permanently attached, preferable by swaging or other mechanical deformation process, to the ends of a control cable or core that reciprocates within an outer casing. The fittings have a projected width no greater than the inner diameter of the casing. As a result, the entire control cable, with fittings attached, can be pulled through the casing to remove the control cable for inspection, maintenance or replacement. The cable also have a unique combination of ball joint assemblies and excluder seals that effectively exclude contaminants from the interior of the casing.
Briefly summarize the main idea's components and working principles as described in the context.
[ "FIELD OF THE INVENTION [0001] This invention relates to mechanical control assemblies, and more particularly to push-pull or reciprocating cable assemblies suitable for aeronautical applications.", "BACKGROUND [0002] Push-pull control cable assemblies are used for many systems, e.g. aircraft engines, which must be adjusted from a distance or which are located in hostile environments.", "These controls frequently have a cable that reciprocates within a casing that supports and protects the cable.", "Fittings are typically attached to both ends of the cable to connect it to a system to be controlled at one end, and to operating levers, pedals and the like at the other end.", "[0003] With existing controls of this type, the entire control cable assembly must be removed for repair or replacement, and the cable itself cannot be thoroughly inspected without removal of fittings permanently attached to each end.", "When these cables fail, they are normally discarded and replaced.", "To facilitate inspection, repair and replacement, a control assembly with a reciprocating cable that can be removed from the casing without removing or disassembling the casing would be desirable.", "SUMMARY OF THE INVENTION [0004] This invention provides improved control cable assemblies having control cables mounted within and adapted for reciprocation within an outer casing.", "A fitting is permanently attached, preferable by swaging or other mechanical deformation process, to at least one end, normally both ends, of the control cable.", "These fittings have a projected width, i.e. the width in a plane at right angles to the axis of the cable, no greater than the inner diameter of the casing.", "As a result, the entire control cable, with fittings attached, can be pulled through the casing to remove the control cable for inspection, maintenance or replacement.", "This simplifies maintenance, and substantially increases the service life of the cable assembly.", "To facilitate connection to control levers, pedals or the like, or to apparatus to be controlled or operated, couplings or other connecting members may be detachably secured to the fittings by renewable connections such as threaded joints, for example, that allow the couplings to be removed and replaced easily.", "[0005] The invention also provides a unique combination of ball joint assemblies and excluder seals that effectively exclude contaminants from the interior of the casing, which also helps to increase service life.", "These and other features of the inventive cable are described more thoroughly in the following detailed description.", "DRAWINGS [0006] [0006 ]FIG. 1 is a fragmentary, partially cutaway plan view of a control cable assembly embodying this invention.", "[0007] [0007 ]FIG. 2 is a cross-sectional view along lines 2 - 2 in FIG. 1. [0008] [0008 ]FIG. 3 is an enlarged cross-sectional view of a ball joint assembly in the control cable assembly illustrated in FIGS. 1 and 2.", "[0009] [0009 ]FIG. 4 is a further enlarged cross-sectional view of an excluder seal in the control cable assembly of FIGS. 1 and 2.", "[0010] [0010 ]FIG. 5 is an end view of the excluder seal in FIG. 4, partially cut away to show parts of the excluder seal in more detail.", "DETAILED DESCRIPTION [0011] [0011 ]FIG. 1 illustrates a control cable assembly, generally referred to as 10 , embodying this invention.", "Cable assembly 10 may extend from the cockpit of an aircraft, or another operating area, to an engine compartment or other remote or hostile location.", "The cable assembly has a control cable 20 adapted for reciprocation within a casing 40 .", "Casing 40 typically extends through a bulkhead fitting 15 in a wall or other partition between the aircraft cockpit, or other operating area, and the compartment where the engine or other system to be controlled is located.", "[0012] Each end of control cable 20 has an end rod 28 with a threaded end 32 for attaching a connecting member, such as the couplings 38 illustrated in FIG. 1, that attach the end rods 28 to control levers, pedals or the like in an aircraft cabin or other operating compartment, or to an engine or other system to be controlled.", "The diameter of the end rods 28 is less than the inner diameter of the casing 40 .", "This allows the control cable 20 , with end rods attached, to be pulled through the casing 40 and removed for inspection, repair or replacement when a coupling 38 has been removed from one of the end rods.", "In most cases, both ends of the control cable 20 are substantially the same.", "Thus, the cable can normally be removed in either direction.", "However, there may be modifications for particular applications, such as differences in the threads on the end rods.", "[0013] The ability to remove control cable 20 from casing 40 permits servicing, maintenance and repairs that were not possible with prior art control cable assemblies, whose central cables could not be removed without removing end fittings that were permanently attached to this control cable by swaging or the like.", "This is not a problem with the control cables of this invention, however, because the end rods that are permanently attached to the cables can pulled through the casing.", "Typically, couplings 38 or other connecting members, designed for connections with engines or other systems to be operated or controlled, or to control levers, pedals or the like, are attached to the end rods with threaded or other renewable connections that allow the connecting members to be removed without distorting or damaging either the end rods or the connecting members.", "Thus, the control cable can be removed from the casing and the connecting members can be replaced or reinstalled when the control cable has been reinstalled or replaced.", "The ability to remove and reinstall or replace the control cable in this manner reduces the cost of maintaining and repairing the cable assembly 10 , and tends to increase its useable life.", "[0014] The central part of control cable 20 is similar to prior control systems of this sort.", "It consists of a flexible core 22 of stranded wire covered with an armor construction or cover formed by steel flats 24 wrapped around the stranded wire core 22 .", "The steel flats protect the stranded wire core from wear, crushing and the like, and support the core if it is placed in compression.", "As best seen in FIG. 2, the armor is peeled from or left off the end of the core, which is inserted into a cylindrical bore 34 in end rod 28 .", "The thin cylindrical shell 36 that surrounds bore 34 is then mechanically swaged or compressed to clamp end rod 28 to the bare core 22 on the end of the flexible cable with sufficient compression to maintain a secure connection between the end rod 28 and core 22 when the cable 20 is placed in tension.", "[0015] The central part of casing 40 is also similar to prior control cable assemblies.", "A stranded wire conduit 42 is wrapped with steel flats 44 that are similar to the flats 24 that form the armor cover on the core 22 .", "The stranded wire conduit 42 is lined with a polytetrafluoroethylene tube 46 that reduces friction on the control cable 20 .", "[0016] As shown in FIG. 2, casing 40 extends into cylindrical bores 52 in casing caps 48 , and the thin annular shells 54 that surround the cylindrical bores 52 are mechanically swaged to lock the casing caps securely on the casing assembly.", "Like the swaged connection between the end rod and the central core 22 , this connection provides a robust, dependable connection.", "The joints between the casing assembly 40 and the casing caps 48 are sealed with a watertight, two piece epoxy sealant to exclude foreign material at these joints.", "[0017] The ends of the cable 20 extend through support tubes 62 , mounted in ball joint housings 74 threaded onto casing caps 48 .", "As best seen in FIG. 2, the joints between the end rods 28 and cable 20 are preferably located in the central portions of the support tubes 62 .", "The end rods extend through excluder seal assemblies 110 , described in more detail below, attached to the outer ends of the support tubes.", "The control cables 20 extend through casing caps 48 into enlarged, substantially spherical knobs 66 at the inner ends of the support tubes 62 .", "These knobs 66 are enclosed within generally cylindrical ball joint housings 74 that allow the end rods to pivot through at an angle of at least 5 [0018] ° in any direction from the illustrated central position.", "In other words, the end rod can swivel within a cone having a central angle of 10° or more.", "As shown in FIG. 3, an inwardly extending shoulder 76 on each housing defines a hole 78 which is slightly larger than the section of the support tube extending through this hole.", "This allows the support tube and end rod to pivot within the specified limits, but prevents excessive movement which could damage the flexible core within the ball joint.", "As best seen in FIG. 3, the ends of control cable 20 enter the enlarged knobs on the support tubes through conical bores 68 , which typically have a cone angle roughly equal to the angle of the cone within which the support tubes can pivot.", "The sides of these conical bores help to support the control cable when the end rods pivot.", "[0019] As also shown in FIG. 3, the enlarged knobs 66 at the inner ends of the support tubes are sealed within ball joint housings 74 by pairs of polytetrafluoroethylene seals 92 , 96 .", "Springs 82 , held in place by retaining rings 84 mounted in grooves in the inner walls of the housings, press seals 92 against the spherical ends 66 of the support tubes.", "The spherical ends of the support tubes press against seals 96 , which are held in place by the inwardly extending shoulders 76 on the end of the housings 74 .", "Seals 92 and 96 protect the cable assembly from contamination along the surface of the of the support tubes 62 .", "O-rings 94 , 98 at the outer corners of seals 92 and 96 seal against the inner walls of the ball joint housings 74 and minimize the potential for contamination at these points.", "[0020] As mentioned above, each end rod 28 extends through an excluder seal assembly 110 , shown in FIG. 4 and 5 .", "The excluder seal assembly 110 has a U-cup rod seal 114 , commercially available from Shamban Seals, mounted in a nose cap 112 treaded onto the outer end of support tube 62 .", "Rod seal 114 is energized by a spring 116 which presses against the end of the support tube.", "The compressed spring 116 presses the U-cup rod seal against end rod 28 , providing a dependable seal at this juncture.", "[0021] The excluder seal assembly also incorporates a pair of knife-like conical brass wiper rings 122 , 132 , shown in FIGS. 4 and 5 and commercially available from Wynn's Precision, Inc, Houston, Texas, which act as blades to remove and dispose of foreign matter on the end rod 28 , thereby protecting the U-cup rod seals.", "Each of these rings has a flange 124 , 134 at its base or inner end.", "The wiper rings are held in place by a cushion ring 138 of an elastomeric materials such as nitrile, butyl, fluoroelastomers or PTFE.", "As shown in FIG. 5, each of the wiper rings 122 , 132 has a pair of slits or notches 126 , 136 , spaced 180° degrees apart in the conical wall and oriented so that the slits 126 in the inner wiper ring 122 are not aligned with the slits 136 in the outer wiper ring seal.", "These slits provide flexibility, allow for expansion, and produce a spring effect resulting in constant contact with the end rod 28 , full circle.", "When compressed, cushion ring 128 preloads the wiper rings for wiper edge contact with the end rods 28 , and absorb shock and side loads.", "The seal is self adjusting.", "The wiper rings lengthen the life of the U-cup seals by keeping foreign material from damaging the lips of the U-cup seals, and provide a secondary seal that further reduces the risk of contamination.", "[0022] The combination of the PTFE/o-ring seals in the ball joint assembly 60 and the spring energized U-cup rod seals and wiper rings in the excluder seal assembly 110 provide increased and dependable protection against contamination from foreign materials entering the cable, thus increasing the anticipated life of the cable assembly.", "As those skilled in the art will readily appreciate, the removable core assemblies of these inventive cables also facilitate servicing, maintenance and repairs, which increases the anticipated service life still further.", "Of course, as those skilled in the art will also appreciate, the control cable assembly shown and described herein is merely illustrative.", "Many modifications to and adaptations of the illustrated assembly may be made within the scope of this invention, which is defined by the following claims." ]
BACKGROUND OF THE INVENTION In certain known types of motion picture cameras, an exposure metering device is provided, whose light sensitive element receives light coming through the camera lens by means of a reflecting surface arranged on the shutter. In this connection, the expressions "metering device" and "metering means" are intended to be interpreted in a broad sense, including devices which merely give an indication of the correct exposure without actually adjusting or controlling the exposure, and also devices which actually adjust or control the exposure, without necessarily giving a visible indication of the correct exposure or its numerical value. It is desirable to provide the light sensitive element or photoelectric element of the exposure metering means with the same amount of light (for a given brightness of scene) at regular intervals, regardless of whether the shutter is rotating or is stationary. In known cameras of this type, the means for providing the photoelectric element with the same quantity of light consists, for example, in providing a frosted reflecting surface on that portion of the shutter which is located behind the lens, in the stationary state of the shutter. By this means, the light intensity measured behind the lens is reduced, when the shutter is stationary, by an amount corresponding to the recess on the rotating reflecting surface. It is very difficult to bring about an accurate behavior of the frosted surface so that it is always the same in different cameras being constructed in sequence. Moreover, there is usually a certain range of tolerance in the light sensitive elements installed in the cameras. Therefore, an accurate setting of the exposure metering means is very difficult to achieve, to obtain uniformity in both the rotating and the stationary positions of the shutter, and a relatively wide tolerance has had to be accepted, in the past, within the production run of manufacturing a quantity of theoretically identical cameras. The object of the present invention, therefore, is to provide a camera of this type with means for delivering the same amount of light to the light sensitive element at regular intervals, with the shutter rotating and with the shutter stationary. Another object is to provide for a simple calibration adjustment capable of being made easily during the assembly of the camera, to set the exposure metering means accurately, thus compensating for the inevitable tolerances of the constructional elements. SUMMARY OF THE INVENTION According to the present invention, the above mentioned objects are accomplished by arranging in the ray path between the shutter and the light sensitive element a reflective surface which can be swung from one to the other of two positions, in both of which it conducts light to the light sensitive element, but in one of which, corresponding to the stationary position of the shutter, the light transmitted to the light sensitive element is cut down or reduced as compared to the amount of light reaching this element when the shutter is rotating. By a slight variation of one or both of the fixed limit positions of the reflective surface, it is possible to achieve an accurate setting of the exposure metering device in either operating condition of the shutter. According to a further development of the invention, this can be implemented in a particularly simple manner if the reflective surface is rigidly connected to a bracket abutting a stop member in either of the two limit positions, and if an adjustment is provided for at least the stop means which determines the position of the reflective surface when the shutter is stationary. It is particularly easy to provide such an adjustment by designing the bracket with a bendable tongue, with which it abuts the stationary stop member in the reflective surface position associated with the stationary shutter. The exact position of the reflective surface when the shutter is stationary, can thus be calibrated by a simple bending of the tongue. In a further development of the invention, means is provided for shifting the reflective surface by operation of the camera release, so that when the camera release member is operated to cause the shutter to rotate, this swings the reflective surface to one of its limit positions, and when the camera release member is let go, to stop the rotation of the shutter, this swings the reflective member to the other of its limit positions. In a further development of the invention, this means for shifting the reflective surface upon operation of the camera release member, comprises a snap-action switch or toggle switch which is actuated by the camera release member and which acts on the bracket connected to the reflective surface, to hold the bracket in the position associated with the rotating shutter, when the camera release is pressed, and a spring which acts on the bracket and which loads the bracket in the opposite direction and which is operative when the camera release member is released. BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is somewhat schematic or diagrammatic illustration of the invention, largely in the form of a section taken along the optical axis of the camera. DESCRIPTION OF THE PREFERRED EMBODIMENT The lens of a motion picture camera is indicated schematically at 1, and is mounted in the usual way in a suitable housing or casing which is of conventional form and is not illustrated. Through this lens, which may have a number of components, light passes to the film gate aperture 2 and to the sensitized film 22, located behind this aperture, the film being advanced intermittently or step by step in the usual manner by means of a conventional claw 33. Rotating on the shaft 3 is a shutter 4 arranged in known manner in the ray path between the lens 1 and the film gate aperture 2. The shutter is designed like a truncated cone and is arranged so that the body of the cone lies in the ray path between the lens and the film, except where a portion of the cone is cut away at 5, so that as the shutter rotates, light may pass along the optical axis to the film when the cut away portion 5 is momentarily at the optical axis. Except at this cut away portion 5, the frusto-conical edge 6 of the shutter lies in the path of the light beam or ray entering the camera. This frusto-conical surface 6 is a reflecting surface, and reflects the light coming through the lens of the camera at a specific angle, preferably 90°. In the ray path of this reflected light reflected by the surface 6, there is arranged another reflective surface 7 which has such a position that, when the shutter 4 is rotating, it will receive the light reflected from the surface 6 of the shutter and conduct such light to the light sensitive element 8 of the exposure metering device or means. This light sensitive element 8 is connected to a device 9, which may be either a meter observable by the operator to indicate to him the proper shutter speed or lens aperture to be set, or a device of known conventional construction which actually controls either the shutter speed or the lens aperture or both. The reflecting surface 7 is arranged in roller 10, diametrically with respect to the rotary axis 11 thereof. A bracket 12 is firmly connected to the roller 10, to swing therewith as the roller turns. This bracket 12 is bifurcated, having one arm 12a and a second arm 12b lying on opposite sides of a fixed stop member 13. As will be readily seen in the drawing, the arm 12a of the bracket will come into contact with the fixed stop 13 to limit the swinging of the roller 10 and reflector 7 in a counterclockwise direction, while the other arm 12b will come into contact with the fixed stop 13 to limit the rotation of the roller 10 and reflecting surface 7 in the opposite or clockwise direction. The arm 12b is in the form of a bendable ear, which can be readily bent during the process of assembling the camera, to provide a fine calibration or adjustment of the exact position of the reflecting surface 7 and roller 10 at its clockwise limit of motion. A spring 14 acts on the arm 12a to bias it in a clockwise direction, to tend to hold the arm 12b tight against the fixed stop 13. Another spring 15 has one end also connected to the arm 12a to tend to pull it the opposite or counterclockwise direction. The opposite end of this spring 15 is connected to a snap-action member or toggle member indicated schematically at 16, which is operated by the camera release member 17. When the camera release member 17 is pressed rightwardly when viewed as in the drawing, to start the operation of the camera in the conventional way, this causes the snap-action or dead-center member 16 to push downwardly on the part thereof that is connected to the lower end of the spring 15, pulling downwardly on this spring. The spring 15 is stronger than the spring 14, so the bracket 12 will be pulled downwardly until the arm 12a thereof comes into contact with the fixed stop 13. This will swing the reflecting member 7 counterclockwise to its limit position corresponding to the rotation of the shutter, and during the rotation, light will be reflected from the reflecting surface 6 of the shutter to the reflecting surface 7, and from the latter to the light sensitive element 8. When it is desired to stop the action of the camera, the camera release member 17 is let go or released, and the action of the springs 14 and 15 swing the dead-center actuator over to the opposite side of its dead-center, releasing the downward pull on the spring 15 sufficiently so that the spring 14 can now swing the bracket arm 12 upwardly or clockwise until the arm 12b thereof comes into contact with the fixed stop 13. This swings the reflecting surface 7 slightly in a clockwise direction, sufficiently to cut down the transmission of reflected light on to the light sensitive element 8 just enough to compensate for the fact that the shutter is now stationary rather than rotating. Assuming that the scene brightness remains the same as it was while the shutter was rotating, the same amount of light will now fall on the light sensitive element 8 as when the shutter was rotating, and the meter or control mechanism 9 will be actuated to the same extent. It is believed the operation will be clear from what has been said above. When the shutter of the camera is operating and the reflecting member 7 is at its counterclockwise limit of motion, almost the entire light reflected by the reflecting surface 6 of the shutter and passing to the reflecting surface 7 will be conducted to the light sensitive element 8. When the operation of the camera is stopped so that the shutter no longer rotates, a considerably greater amount of light entering the camera is reflected by the shutter surface 6 onto the reflecting surface 7, as well understood in the art. But at this time the position of the reflecting surface 7 is shifted to its clockwise limit of motion, cutting down the amount of light transmitted from the surface 7 to the light sensitive element 8, just enough to compensate for the greater amount of light reflected by the shutter surface 6. Notwithstanding tolerance variations in the light sensitive element 8 or in the reflective efficiency of the shutter surface 6, from one camera to another during a production run of a number of such cameras, the light transmission from the surface 7 to the element 8 can be easily calibrated or adjusted to achieve just the right amount of light transmission to the element 8, by bending the bendable tongue 12b. With the camera not operating (that is, with the shutter 4 not rotating) the downward spring force acting through the spring 15 and its connections onto the bracket 12, is either zero, or is at least less than the upward force exerted by the spring 14. It is seen from the foregoing that the above mentioned objects of the invention have been well achieved in a simple manner.
A motion picture camera wherein a part of the light entering the camera lens from the subject being photographed is reflected by a reflector on the shutter to a light sensitive element of exposure metering means. In order to insure that, for a given degree of brightness of the scene, the same quantity of light reaches the sensitive element regardless of whether the shutter is in motion or is stationary, an adjustable reflector is interposed between the shutter and the light sensitive element. This adjustable reflector is shifted from one position to another position by operation of the camera release member. A bendable ear is provided for calibration purposes.
Briefly summarize the main idea's components and working principles as described in the context.
[ "BACKGROUND OF THE INVENTION In certain known types of motion picture cameras, an exposure metering device is provided, whose light sensitive element receives light coming through the camera lens by means of a reflecting surface arranged on the shutter.", "In this connection, the expressions "metering device"", "and "metering means"", "are intended to be interpreted in a broad sense, including devices which merely give an indication of the correct exposure without actually adjusting or controlling the exposure, and also devices which actually adjust or control the exposure, without necessarily giving a visible indication of the correct exposure or its numerical value.", "It is desirable to provide the light sensitive element or photoelectric element of the exposure metering means with the same amount of light (for a given brightness of scene) at regular intervals, regardless of whether the shutter is rotating or is stationary.", "In known cameras of this type, the means for providing the photoelectric element with the same quantity of light consists, for example, in providing a frosted reflecting surface on that portion of the shutter which is located behind the lens, in the stationary state of the shutter.", "By this means, the light intensity measured behind the lens is reduced, when the shutter is stationary, by an amount corresponding to the recess on the rotating reflecting surface.", "It is very difficult to bring about an accurate behavior of the frosted surface so that it is always the same in different cameras being constructed in sequence.", "Moreover, there is usually a certain range of tolerance in the light sensitive elements installed in the cameras.", "Therefore, an accurate setting of the exposure metering means is very difficult to achieve, to obtain uniformity in both the rotating and the stationary positions of the shutter, and a relatively wide tolerance has had to be accepted, in the past, within the production run of manufacturing a quantity of theoretically identical cameras.", "The object of the present invention, therefore, is to provide a camera of this type with means for delivering the same amount of light to the light sensitive element at regular intervals, with the shutter rotating and with the shutter stationary.", "Another object is to provide for a simple calibration adjustment capable of being made easily during the assembly of the camera, to set the exposure metering means accurately, thus compensating for the inevitable tolerances of the constructional elements.", "SUMMARY OF THE INVENTION According to the present invention, the above mentioned objects are accomplished by arranging in the ray path between the shutter and the light sensitive element a reflective surface which can be swung from one to the other of two positions, in both of which it conducts light to the light sensitive element, but in one of which, corresponding to the stationary position of the shutter, the light transmitted to the light sensitive element is cut down or reduced as compared to the amount of light reaching this element when the shutter is rotating.", "By a slight variation of one or both of the fixed limit positions of the reflective surface, it is possible to achieve an accurate setting of the exposure metering device in either operating condition of the shutter.", "According to a further development of the invention, this can be implemented in a particularly simple manner if the reflective surface is rigidly connected to a bracket abutting a stop member in either of the two limit positions, and if an adjustment is provided for at least the stop means which determines the position of the reflective surface when the shutter is stationary.", "It is particularly easy to provide such an adjustment by designing the bracket with a bendable tongue, with which it abuts the stationary stop member in the reflective surface position associated with the stationary shutter.", "The exact position of the reflective surface when the shutter is stationary, can thus be calibrated by a simple bending of the tongue.", "In a further development of the invention, means is provided for shifting the reflective surface by operation of the camera release, so that when the camera release member is operated to cause the shutter to rotate, this swings the reflective surface to one of its limit positions, and when the camera release member is let go, to stop the rotation of the shutter, this swings the reflective member to the other of its limit positions.", "In a further development of the invention, this means for shifting the reflective surface upon operation of the camera release member, comprises a snap-action switch or toggle switch which is actuated by the camera release member and which acts on the bracket connected to the reflective surface, to hold the bracket in the position associated with the rotating shutter, when the camera release is pressed, and a spring which acts on the bracket and which loads the bracket in the opposite direction and which is operative when the camera release member is released.", "BRIEF DESCRIPTION OF THE DRAWING The single FIGURE is somewhat schematic or diagrammatic illustration of the invention, largely in the form of a section taken along the optical axis of the camera.", "DESCRIPTION OF THE PREFERRED EMBODIMENT The lens of a motion picture camera is indicated schematically at 1, and is mounted in the usual way in a suitable housing or casing which is of conventional form and is not illustrated.", "Through this lens, which may have a number of components, light passes to the film gate aperture 2 and to the sensitized film 22, located behind this aperture, the film being advanced intermittently or step by step in the usual manner by means of a conventional claw 33.", "Rotating on the shaft 3 is a shutter 4 arranged in known manner in the ray path between the lens 1 and the film gate aperture 2.", "The shutter is designed like a truncated cone and is arranged so that the body of the cone lies in the ray path between the lens and the film, except where a portion of the cone is cut away at 5, so that as the shutter rotates, light may pass along the optical axis to the film when the cut away portion 5 is momentarily at the optical axis.", "Except at this cut away portion 5, the frusto-conical edge 6 of the shutter lies in the path of the light beam or ray entering the camera.", "This frusto-conical surface 6 is a reflecting surface, and reflects the light coming through the lens of the camera at a specific angle, preferably 90°.", "In the ray path of this reflected light reflected by the surface 6, there is arranged another reflective surface 7 which has such a position that, when the shutter 4 is rotating, it will receive the light reflected from the surface 6 of the shutter and conduct such light to the light sensitive element 8 of the exposure metering device or means.", "This light sensitive element 8 is connected to a device 9, which may be either a meter observable by the operator to indicate to him the proper shutter speed or lens aperture to be set, or a device of known conventional construction which actually controls either the shutter speed or the lens aperture or both.", "The reflecting surface 7 is arranged in roller 10, diametrically with respect to the rotary axis 11 thereof.", "A bracket 12 is firmly connected to the roller 10, to swing therewith as the roller turns.", "This bracket 12 is bifurcated, having one arm 12a and a second arm 12b lying on opposite sides of a fixed stop member 13.", "As will be readily seen in the drawing, the arm 12a of the bracket will come into contact with the fixed stop 13 to limit the swinging of the roller 10 and reflector 7 in a counterclockwise direction, while the other arm 12b will come into contact with the fixed stop 13 to limit the rotation of the roller 10 and reflecting surface 7 in the opposite or clockwise direction.", "The arm 12b is in the form of a bendable ear, which can be readily bent during the process of assembling the camera, to provide a fine calibration or adjustment of the exact position of the reflecting surface 7 and roller 10 at its clockwise limit of motion.", "A spring 14 acts on the arm 12a to bias it in a clockwise direction, to tend to hold the arm 12b tight against the fixed stop 13.", "Another spring 15 has one end also connected to the arm 12a to tend to pull it the opposite or counterclockwise direction.", "The opposite end of this spring 15 is connected to a snap-action member or toggle member indicated schematically at 16, which is operated by the camera release member 17.", "When the camera release member 17 is pressed rightwardly when viewed as in the drawing, to start the operation of the camera in the conventional way, this causes the snap-action or dead-center member 16 to push downwardly on the part thereof that is connected to the lower end of the spring 15, pulling downwardly on this spring.", "The spring 15 is stronger than the spring 14, so the bracket 12 will be pulled downwardly until the arm 12a thereof comes into contact with the fixed stop 13.", "This will swing the reflecting member 7 counterclockwise to its limit position corresponding to the rotation of the shutter, and during the rotation, light will be reflected from the reflecting surface 6 of the shutter to the reflecting surface 7, and from the latter to the light sensitive element 8.", "When it is desired to stop the action of the camera, the camera release member 17 is let go or released, and the action of the springs 14 and 15 swing the dead-center actuator over to the opposite side of its dead-center, releasing the downward pull on the spring 15 sufficiently so that the spring 14 can now swing the bracket arm 12 upwardly or clockwise until the arm 12b thereof comes into contact with the fixed stop 13.", "This swings the reflecting surface 7 slightly in a clockwise direction, sufficiently to cut down the transmission of reflected light on to the light sensitive element 8 just enough to compensate for the fact that the shutter is now stationary rather than rotating.", "Assuming that the scene brightness remains the same as it was while the shutter was rotating, the same amount of light will now fall on the light sensitive element 8 as when the shutter was rotating, and the meter or control mechanism 9 will be actuated to the same extent.", "It is believed the operation will be clear from what has been said above.", "When the shutter of the camera is operating and the reflecting member 7 is at its counterclockwise limit of motion, almost the entire light reflected by the reflecting surface 6 of the shutter and passing to the reflecting surface 7 will be conducted to the light sensitive element 8.", "When the operation of the camera is stopped so that the shutter no longer rotates, a considerably greater amount of light entering the camera is reflected by the shutter surface 6 onto the reflecting surface 7, as well understood in the art.", "But at this time the position of the reflecting surface 7 is shifted to its clockwise limit of motion, cutting down the amount of light transmitted from the surface 7 to the light sensitive element 8, just enough to compensate for the greater amount of light reflected by the shutter surface 6.", "Notwithstanding tolerance variations in the light sensitive element 8 or in the reflective efficiency of the shutter surface 6, from one camera to another during a production run of a number of such cameras, the light transmission from the surface 7 to the element 8 can be easily calibrated or adjusted to achieve just the right amount of light transmission to the element 8, by bending the bendable tongue 12b.", "With the camera not operating (that is, with the shutter 4 not rotating) the downward spring force acting through the spring 15 and its connections onto the bracket 12, is either zero, or is at least less than the upward force exerted by the spring 14.", "It is seen from the foregoing that the above mentioned objects of the invention have been well achieved in a simple manner." ]
RELATED APPLICATIONS [0001] This application claims priority from the U.S. provisional application filed on 31 Mar. 2016 and assigned application No. 62/316,251, which application is incorporated herein by reference. TECHNICAL FIELD [0002] The present invention generally relates to position encoders and particularly relates to compensating for errors arising from harmonic components present in position encoder signals. BACKGROUND [0003] A sinusoidal encoder outputs a pair of sinusoidal signals in quadrature phase relationship, with distance covered over one signal cycle of the encoder being referred to as one “line” of the encoder. The term “sinusoid” is used loosely in this context because some encoders, particularly less expensive encoders, output only rough approximations of sinusoids, or otherwise output sinusoids with significant harmonic components in addition to the fundamental frequency component. [0004] A coarse physical position (“position”) may be tracked by a running count of the signal cycles over multiple lines of the encoder, and much finer incremental positions may be tracked within each signal cycle via “interpolation.” One technique for interpolating the position within each signal cycle relies on the arctangent function, which expresses the incremental or fine position within the current signal cycle as: [0000] ∅ fine = tan - 1  ( V sin V cos ) , [0000] where V sin and V cos are the instantaneous signal values of the quadrature waveforms output by the encoder. So-called “encoder interpolators” exploit the foregoing angular relationship to provide high-resolution tracking of position within each recurring cycle of a sinusoidal encoder. Precision machining and many other motion-control applications require the higher resolutions that can be provided by good encoder interpolators. [0005] However, errors in the encoder signals directly affect accuracy in position determination, and this point holds true whether the encoder encodes angular or linear positions of a physical system. Merely by way of example, the physical system may be a robotic arm, a machine tool head, or a workpiece holder. [0006] Known approaches to compensation for imperfections—errors—in the encoder signals typically operate in the “encoder domain,” which is another way of saying that the corrections are detected and applied with respect to the output signals provided by the encoder in question. Consider, for example, the encoder interpolator detailed in U.S. Pat. No. 8,384,570, which patent is incorporated herein by reference and discloses techniques for compensating for fundamental errors in the encoder signals. Here, fundamental errors include any one or more of voltage offsets on the encoder signals, magnitude mismatches between the encoder signals, and phase error between the encoder signals. The '570 patent provides for such compensation by adjusting the numerical values sampled from the encoder signals. [0007] Potentially significant errors in position detection arise because of harmonic components in the encoder signals. The encoder signals output from a sinusoidal encoder include a fundamental frequency component, which can be understood as the “desired” signal. Unfortunately, the encoder signals may also include undesirable harmonic components. Known encoder compensation techniques contemplate limited forms of harmonic compensation. [0008] U.S. Pat. No. 7,109,900, for example, describes a technique for detecting and compensating the third harmonic component present in encoder signals. The disclosed approach operates in the encoder domain and relies on examining the Lissajous patterns resulting from converting the encoder signals—i.e., sine and cosine signals—into corresponding radius and angle values. Computational complexity limits the viability of the technique, and that complexity especially discourages extension of the technique to higher harmonic components of the fundamental frequency. SUMMARY [0009] Methods and apparatus disclosed herein implement or otherwise embody a technique that compensates for cyclic position errors in encoder-based position detection, wherein the cyclic position errors arise from the presence of harmonic components in the encoder signals relied upon for position determination. Using position-domain compensation for errors arising in the encoder domain offers computational simplicity and impressive compensation performance, even when compensating for a plurality of higher harmonics in the encoder signals, e.g., third harmonic, fifth harmonic, etc. Consequently, even high-precision position monitoring or control can use relatively inexpensive types of encoders known to output encoder signals having significant harmonic components. [0010] In an example embodiment, a method of encoder interpolation includes receiving encoder signals from a sinusoidal encoder, sampling the encoder signals to obtain sampled signal values, calculating positions from the sampled signal values, obtaining corrected positions by applying corresponding correction values to the calculated positions, and forming extended positions comprising the corrected positions and a current cycle count associated with the encoder signals. The method further includes determining position errors between the extended positions and corresponding estimated positions, as estimated by a digital state estimator that constrains position estimation according to a mathematical model of a physical system whose position is being tracked by the sinusoidal encoder, and outputting the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of a physical system. [0011] Still further, the method includes determining the correction values by processing the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors, and determining the correction values as a function of the determined magnitudes. Such processing will be understood as detecting and correcting—compensating for—cyclic position errors in the “position” domain, which offers significant computational efficiency as compared to detecting and correcting encoder errors in the encoder signals. [0012] In another example embodiment, an encoder interpolator includes input circuitry configured to receive encoder signals from a sinusoidal encoder and sample the encoder signals to obtain sampled signal values, and processing circuitry configured to calculate positions from the sampled signal values, obtain corrected positions by applying corresponding correction values to the calculated positions, and form extended positions comprising the corrected positions and a current cycle count associated with the encoder signals. The encoder interpolator further includes output circuitry configured to output the extended positions or a filtered version thereof, for use in monitoring or controlling the position of a physical system. [0013] Within the above processing framework, the processing circuitry is configured to determine position errors between the extended positions and corresponding estimated positions, as estimated by an included digital state estimator that constrains position estimation according to a mathematical model of a physical system whose position is being tracked by the sinusoidal encoder. Further, to determine the correction values, the processing circuitry is configured to process the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors, and determine the correction values as a function of the determined magnitudes. [0014] Of course, the present invention is not limited to the above features and advantages. Those of ordinary skill in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a block diagram of one embodiment of an encoder interpolator. [0016] FIG. 2 is a logic flow diagram of a method of encoder interpolation. [0017] FIG. 3 is a block diagram of one embodiment of processing circuitry configured for encoder interpolation. DETAILED DESCRIPTION [0018] FIG. 1 depicts a sinusoidal encoder 8 that is used to track the position of a physical system. The position information is encoded in its output signals, which are at least nominally a pair of analog sinusoids in quadrature relationship. An encoder interpolator 10 receives the encoder signals and processes them for monitoring or controlling the position of the physical system. Movement of the physical system may be linear or angular, or a combination of linear and angular movement, and the encoder signals may encode linear or angular position. [0019] The encoder interpolator 10 includes interface circuitry 12 , which includes input circuitry 14 and output circuitry 16 . Further included in the example implementation are processing circuitry 20 , which includes or otherwise implements a digital state estimator 22 , and which includes or is associated with storage 24 . The storage 24 in one or more embodiments stores a data structure or set of parameters comprising a mathematical model of the physical system 26 , for use by the digital state estimator 22 , which uses the system model to estimate positions in correspondence with processing the encoder signals incoming to the encoder interpolator 10 . It is also possible for the mathematical model 26 to be incorporated or otherwise hard-coded in the digital state estimator 22 . [0020] In at least some embodiments, the storage 24 stores a computer program 28 comprising program instructions that, when executed by a processor, e.g., a microprocessor, within the encoder interpolator 10 , causes the encoder interpolator 10 to operate as described herein. Thus, in at least one embodiment, the processing circuitry 20 is realized at least in part by executing computer instructions in one or more processing circuits. More generally, the processing circuitry 20 may be fixed circuitry, programmable circuitry, or a mix of both fixed and programmable circuitry. Correspondingly, the storage 24 in such embodiments comprises one or more types of computer-readable media, such as volatile working memory and non-volatile program memory. Non-limiting examples include any one or more of FLASH, EEPROM, DRAM, and SRAM memory circuits or devices. However implemented, the storage 24 may also store various configuration data 30 for the processing circuitry 20 . [0021] With a focus on explaining its operational configuration, the example encoder interpolator 10 comprises input circuitry 14 configured to receive encoder signals from a sinusoidal encoder 8 and sample the encoder signals to obtain sampled signal values. Further, the encoder interpolator 10 includes processing circuitry 20 that is configured to calculate positions from the sampled signal values, obtain corrected positions by applying corresponding correction values to the calculated positions, form extended positions comprising the corrected positions and a current cycle count associated with the encoder signals, determine position errors between the extended positions and corresponding estimated positions, as estimated by the included digital state estimator 22 that constrains position estimation according to a mathematical model of the physical system whose position is being tracked by the sinusoidal encoder 8 . The encoder interpolator 10 further includes output circuitry 16 configured to output the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of the physical system. [0022] To determine the correction values, the processing circuitry 20 is configured to process the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors. Correspondingly, the processing circuitry 20 is configured to determine the correction values as a function of the determined magnitudes. In an example implementation, the processing circuitry 20 is configured to process the position errors on a running basis by performing Fourier-transform processing of the position errors for one or more specific frequencies corresponding to one or more harmonic components for which correction is desired. Limiting the processing to specific frequencies of interest greatly simplifies the associated processing, as compared to performing a Fourier transform over a larger range of frequencies. [0023] The sampling of the input signals, and subsequent processing of the sampled values, including position calculation, digital state estimation, error identification, and position correction, must all operate at a discrete frequency high enough to occur multiple times per the highest position error harmonic to be detected at the maximum physical frequency for which detection is desired. This is a consequence of the well-known Nyquist sampling theorem, which states that such sampling must occur more than twice per cycle of the highest frequency component to be detected. In practice, this means that such sampling and processing must occur at multiple megahertz for typical real-world systems. [0024] More broadly, in one or more embodiments, the processing circuitry 20 is configured to determine the magnitudes of a limited number of harmonic components of the position errors, including at least the fourth harmonic and one or more higher even harmonics. Here, it will be appreciated that odd harmonic components in the encoder signals are manifested as even harmonic components in the position errors. For example, a third harmonic component of the fundamental frequency of the encoder signals results in a fourth harmonic component in the position errors. [0025] Thus, it will be appreciated that the processing circuitry 20 is configured to correct for at least one harmonic component of the position errors and, preferably, is configured to compensate for a fourth harmonic component of the position errors and one or more higher even harmonic components of the position errors. To do so, the processing circuitry 20 is configured to determine the sign and magnitude of the one or more harmonic components of the position errors by calculating coefficients representing the magnitude of sine or cosine components of each harmonic component among the one or more harmonic components of the position errors. When the phrase “sine or cosine” is used herein, and unless otherwise noted or apparent from the context, it shall be understood being one or the other, or both. For example, stating that the processing circuitry 20 determines sine or cosine components of a harmonic component of the position errors shall be understood as saying that the processing circuitry 20 may determine either sine or cosine components, or both sine and cosine components. [0026] As for determining the correction values applied to the positions computed from the encoder signals, the processing circuitry 20 in one or more embodiments is configured to determine the correction values as a function of the determined magnitudes of the sine or cosine components of each harmonic component of the position errors that is being corrected. The processing circuitry 20 does so by, for each calculated position value and each harmonic component of the position errors being corrected, multiplying the calculated position by a multiplier corresponding to the harmonic component being corrected and taking the sine or cosine of the result, and taking the result of the sine or cosine operation and multiplying it by the corresponding coefficient. [0027] In addition to correcting for position errors in the “position domain,” the processing circuitry 20 may be configured to compensate the sampled signal values obtained from the encoder signals for at least one of: signal offsets of the encoder signals, magnitude mismatch of the encoder signals, and quadrature phase error of the encoder signals. Such processing improves the sampled signaled values used by the processing circuitry 20 for initial computation of position from the encoder signals, meaning that the corrected positions reflect both compensation for fundamental errors in the encoder signals, as well as compensation for higher-order errors, e.g., third, fifth, and seventh harmonic components. However, it shall be understood that the compensation for higher-order errors in the encoder signals occurs not in the “encoder domain” but rather in the position domain as noted above. Here, the term “position domain” denotes the detection of cyclic position errors and the correction of those errors, based on processing the positions calculated from the encoder signals. [0028] In one or more embodiments, the encoder interpolator 10 is a component of a larger apparatus, e.g., a motion controller that uses the extended positions determined by the encoder interpolator 10 for its motion-control algorithms. More generally, the encoder interpolator 10 is used in association with monitoring or controlling the position of a physical system and in at least some embodiments includes output circuitry 16 that is configured to output the extended positions or filtered extended positions to a controlling or monitoring apparatus, as numerical values provided in a serial or a parallel format. The processing circuitry 20 or the output circuitry 16 may also be configured to generate and output a digital quadrature signal and corresponding digital sine and cosine signals, corresponding to the encoder signals but compensated for the cyclic position errors detected and corrected for by the processing circuitry 20 . In other words, the encoder interpolator 20 may be configured to output a recreation of the encoder signals—in the digital domain—from which one or more cyclic position errors are removed. [0029] The encoder interpolator 10 in at least some embodiments provides other useful signals as outputs. For example, in operation, the digital state estimator 22 estimates acceleration from the position errors, integrates the acceleration estimates to obtain velocity estimates, and integrates the velocity estimates to obtain position estimates. Advantageously, in one or more embodiments, the output circuitry 16 is configured to output the estimates of acceleration and velocity from the digital state estimator 22 , for use as system feedback states by an associated positioning monitoring or control apparatus. Conventionally, such estimates would remain internal to the state estimation process. [0030] FIG. 2 illustrates one embodiment of a method 200 of encoder interpolation, which may be carried out by the encoder interpolator 10 of FIG. 1 , or which may be carried out using any suitable arrangement of processing circuitry. The method 200 shall be understood as a running process that executes repeatedly within and over cycles of the encoder 8 . [0031] The method 200 includes receiving (Block 202 ) encoder signals from a sinusoidal encoder 8 , sampling (Block 204 ) the encoder signals to obtain sampled signal values, calculating (Block 206 ) positions from the sampled signal values, obtaining (Block 208 ) corrected positions by applying corresponding correction values to the calculated positions, forming (Block 210 ) extended positions comprising the corrected positions and a current cycle count associated with the encoder signals, and outputting (Block 212 ) the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of physical system. [0032] The method 200 further includes, e.g., in a running feedback loop arrangement, determining (Block 214 ) the position errors between the extended positions and corresponding estimated positions, as generated by the digital state estimator 22 . The position errors are used for determining (Block 216 ) the correction values. [0033] The determining step 216 comprises a “running” process within the larger set of ongoing operations and it includes processing (Block 218 ) the position errors on a running basis to determine the sign and magnitude of one or more harmonic components of the position errors, and determining (Block 220 ) the correction values as a function of the determined magnitudes. That is, each newly determined position error feeds into the error-correction process. [0034] The method 200 provides numerous advantages. For example, in the most exacting motion control applications involving the use of high-quality encoders that are already quite good, the compensation of cyclic position errors provides for even higher precision. Further, the method 200 may make it feasible to use lower-quality encoders in at least some applications that would otherwise require more expensive encoders with less harmonic content in their output encoder signals. [0035] On that point, it is common for analog quadrature encoders, even those marketed as “sinusoidal” encoders, to have substantial odd-harmonic content, notably in the third, fifth, seventh, and ninth harmonics. These signal harmonics produce predictable higher even-harmonic position errors in any encoder interpolator that does not compensate for these higher-order harmonics in the encoder signals. For example, matching the third-harmonic component in both encoder signals—i.e., in the quadrature sinusoids output by the encoder—yields cyclic position errors of 4th, 8th, 12th, 16th etc. harmonics of the fundamental signal frequency (the encoder cycle frequency) in any encoder interpolator that lacks the ability to correct for higher-order harmonics in the encoder signals. [0036] If a given harmonic component in the encoder signals is of fraction x of the fundamental signal component, the resulting position error (in radians of a line cycle) can be expressed as: [0000] E = x 1 1  sin   4   θ + x 2 2  sin   8   θ + x 3 3  sin   12   θ + x 4 4  sin   16   θ + … [0037] For example, with x=0.05, the 4th-harmonic component of the position error has a magnitude of 0.05 radians, or 2.86 degrees, of a line cycle, and the 8th-harmonic component has a magnitude of 0.00125 radians, or 0.07 degrees. [0038] Similarly, the position errors resulting from a matching 5th-harmonic signal component in the encoder signals can be expressed as: [0000] E = x 1 1  sin   4   θ - x 2 2  sin   8   θ + x 3 3  sin   12   θ - x 4 4  sin   16   θ + … [0039] Matching 7th-harmonic signal components in the encoder signals yield errors of: [0000] E = x 1 1  sin   8   θ + x 2 2  sin   16   θ + x 3 3  sin   24  θ + x 4 4  sin   32   θ + … [0040] Matching 9th-harmonic signal components in the encoder signals yield errors of: [0000] E = x 1 1  sin   8   θ - x 2 2  sin   16   θ + x 3 3  sin   24   θ - x 4 4  sin   32   θ + … [0041] If the only signal errors in the encoder signals are matching odd harmonics, the resulting position errors are independent and superimposable, with only sin(4N*θ) components. However, if there are fundamental signal errors as well (e.g., quadrature errors, magnitude mismatch, etc.), or if the harmonic component magnitudes are not the same between the sine and cosine signals output from the encoder, there can be cosine position error components as well, and with frequencies of 2N*θ as well. The techniques disclosed herein provide for detection and correction of all such errors. [0042] FIG. 3 depicts one implementation of the encoder interpolator 10 introduced in FIG. 1 . The depicted arrangement provides for robust and automatic detection and correction of cyclic position errors arising from higher harmonic components in the encoder signals input to the encoder interpolator 10 for processing. Certain circuitry depicted in the diagram, such as the sampling circuitry 40 , may be implemented in the interface circuitry 12 of the encoder interpolator 10 . More generally, however, the various computational circuits shall be understood as elements of the overall processing circuitry 20 shown in FIG. 1 . [0043] Analog signals from the encoder 8 (which are at least nominally quadrature sinusoids) are digitized in the sampling circuitry 40 , to produce sampled signal values corresponding to the analog signals. The sampling circuitry 40 may include other conditioning, such as input signal filtering, etc. In any case, processing downstream from the sampling circuitry 40 shall be understood as involving digital values unless otherwise noted. [0044] The arctangent calculation circuit 42 converts the digitized sine and cosine signals into an uncorrected angle within one line of the encoder 8 . It will be appreciated that such operation is carried out on a “running” basis and that the arctangent calculation circuit 42 repeatedly computes line angles during live operation—i.e., multiple line angles are computed within each recurring cycle of the encoder 8 . These line angles may also be referred to as “positions.” Each such position is a digital value representing the instantaneous angle θ, i.e., the measured phase of the encoder signals. The measured phase will exhibit cyclic errors—cyclic position errors—corresponding to higher-order harmonic components in the encoder signals. [0045] Via a combining circuit 44 , each position is combined with a corresponding correction value that compensates for one or more cyclic position errors arising from one or more corresponding harmonic components in the encoder signals. The correction value applied to each position may comprise a composite or combination of values—e.g., correcting for various sine or cosine components of the position error harmonics. [0046] The resulting corrected positions—also referred to as corrected line angles or corrected phase measurements—are “extended” via the extension circuit 46 into so called “extended positions.” Each extended position comprises a corrected position and a running cycle count that reflects the current cycle count of the encoder signals. That is, the corrected position is an instantaneous phase measured within one line of the encoder 8 and the running cycle count is an accumulated count of encoder cycles. A given position together with the running cycle count represents an absolute position and the extended positions are, therefore, absolute positions that are compensated for cyclic position errors. [0047] The extended positions and/or position errors derived therefrom are fed into the digital state estimator 22 , which comprises circuitry that is configured to use a simplified model of the physical system associated with the encoder 8 —e.g., it uses the mathematical model 26 . Because the mathematical model 26 of the physical system does not model or provide for movement frequencies higher than are realistically possible for the physical system, the digital state estimator 22 effectively acts as a low pass filter. Given that the position errors produced by signal harmonics in the encoder signals are at very high temporal frequencies at all but the lowest speeds of the encoder, the operation of the digital state estimator 22 is not very sensitive to the values of the system model constants chosen, especially if the cyclic error determination algorithm is only activated above a minimum velocity threshold. [0048] In any case, the operative point here is that the high-frequency errors between the extended positions and the corresponding estimated positions as produced by the digital state estimator 22 can be attributed to measurement errors because the physical system cannot truly operate at such frequencies. In the diagram, a difference circuit 48 outputs position errors based on taking the difference between each estimated position and the corresponding extended position. Here, “corresponding” denotes the extended and estimated positions corresponding to the same line angle or position. [0049] In this regard, it may be helpful to remember that each extended position comprises a running cycle count and a corrected position, i.e., a corrected angle or phase value θ′ m representing an instantaneous measured phase within one line of the encoder mark, where the accent mark indicates that θ′ m is the corrected version of the corresponding measured value θ m output from the arctangent calculation circuit 42 . In the same fashion, the estimated position generated by the digital state estimator 22 in correspondence with each extended position comprises a running cycle count and an estimated instantaneous position θ e that nominally matches the θ′ m term in the corresponding extended position. [0050] The difference circuit 48 determines position errors by taking the “difference” between each estimated position output from the digital state estimator 22 and the corresponding extended position output from the extension circuit 46 . In particular, the error that is of interest is the difference in instantaneous phase angles, i.e., the difference between the θ′ m term of the extended position and the θ e term of the corresponding estimated position. The phase angle difference may be denoted as Δθ e . Now, it may happen that the running cycle count maintained by the digital state estimator circuit 22 and the running cycle count used by the extension circuit 46 do not roll over at precisely the same instant, and it will be understood that the difference circuit 48 accounts for any rollover discrepancies when determining the difference between the θ′ m and θ e terms of the respective extended and estimated positions. [0051] The position errors Δθ e are fed into the adaptive signal harmonic error identification circuit 54 , which looks for patterns in the position errors. As a non-limiting example, the circuit 54 shown in the diagram is configured to determine error magnitudes for the 4th, 8th, 12th, and 16th harmonics of the position errors, but other components are possible. The error identification in one or more embodiments is done through a Fourier transform algorithm. With only specific frequencies being examined, the processing is much simpler than performing a “continuous” transform. In other words, the circuit 54 can be preconfigured to determine the magnitudes of only certain, predefined harmonic components. For example, the circuit 54 may be configured to generate magnitude coefficients corresponding to only the 4th, 8th, and 12th harmonic components in the position errors, meaning that it need only perform processing corresponding to these preconfigured harmonic components. [0052] In the diagram, the “K” coefficients output from the adaptive signal harmonic error identification circuit 54 are coefficients for the sine or cosine components of the 4th, 8th, 12th, and 16th harmonic components of the position errors, e.g., as determined via Fourier-transform processing on a running series of position errors Δθ e . [0053] On a running basis, the error coefficients calculated by the circuit 54 are multiplied in a sine lookup table circuit 56 using values dependent on the instantaneous angle within an encoder line θ e multiplied by the appropriate harmonic factor N. The resulting products are combined to obtain an overall instantaneous error value—referred to in the diagram as a “CORRECTION VALUES.” Thus, a correction value is subtracted from each instantaneous measured position θ m to obtain the corresponding corrected position θ′ m . Notably, while correction for the sine components of the 4th, 8th, 12th, and 16th harmonics is explicitly shown in the diagram (i.e. K 4 sin 4θ terms and so on), the processing circuitry 20 in one or more embodiments implements a cosine lookup table circuit 58 , and the adaptive signal harmonic identification circuit 54 additionally generates magnitude coefficients corresponding to the cosine component of the position-error harmonics being corrected. These cosine-component magnitude coefficients are used by the cosine lookup table circuit 58 to generate correction values for the cosine components and all such correction values are included in the combining operation used to form the correction value to be subtracted from the current position. [0054] With the cyclic error identification and correction algorithm described above always running (or at least always running above a minimum velocity threshold), the encoder interpolator 10 continuously adapts to error patterns that change over position and time. This operation in turn permits high-accuracy results from encoders that are less expensive to make and to install. Note that the most recently determined corrections may continue to be used even when operating below the minimum velocity threshold. [0055] Configuring which error components are detected and removed by the encoder interpolator reflects various tradeoffs in performance versus complexity. The error components that tend to be the largest are the most important to remove. The higher the harmonic in the encoder signal, the lower the corresponding magnitude of position-error harmonic tends to be. For each harmonic component in the encoder signals, the secondary, and especially tertiary, position-error components are significantly smaller than the primary. As a further consideration, it is noted herein that the cosine components from interactions tend to be smaller than the sine components. [0056] The processing circuitry 20 may output the extended positions directly, or may output a filtered version of the extended positions, such as provided for in the diagram via the moving average filter circuit 50 . There, one sees that the filter circuit 50 outputs filtered extended positions (“FiltExtPos”), for use in position monitoring or control. [0057] In at least some embodiments, the processing circuitry 20 further provides for regeneration of the quadrature encoder signals, which occurs in the digital domain and provides the advantage of generating encoder signals corresponding to the received encoder signals but minus the cyclic position errors corrected by the processing circuitry 20 . Such operations are provided for in the sine/cosine calculation circuit 52 , which outputs a digital quadrature signal (“FiltCorrABquad”) that it derives from the filtered extended positions. The circuit 52 further outputs filtered sinusoids in quadrature (“FiltCorrSine” and “FiltCorrCosine”) that correspond to the encoder signals minus the harmonic encoder-domain content corresponding to the cyclic position errors canceled by the processing circuitry 20 in the position domain. [0058] Still further, the diagram depicts an advantageous implementation of the digital state estimator 22 , such as mentioned earlier. Here, the digital state estimator 22 outputs the estimates of acceleration and velocity that it uses for generating the estimated positions. These values represent feedback states that a downstream motion controller or other downstream processing circuitry would have to estimate for position monitoring or control of the physical system, and it is therefore computationally efficient to provide them from the digital state estimator 22 . The velocity and acceleration values from the high-frequency based estimation performed by the digital state estimator 22 have lower quantization errors and delays than what the downstream controller could compute itself from the position. [0059] Finally, at least some embodiments of the processing circuitry 20 additionally compensate for fundamental errors in the encoder signals, and include a fundamental error correction circuit 60 . The fundamental error correction circuit 60 operates in the “encoder domain” on the encoder signals or the digitized versions thereof, and may be configured according to known techniques to compensate for any one or more of quadrature error in the encoder signals, voltage offsets of the encoder signals, and magnitude mismatch between the encoder signals. [0060] Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure. Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Methods and apparatus disclosed herein implement or otherwise embody a technique that compensates for cyclic position errors in encoder-based position detection, wherein the cyclic position errors arise from the presence of harmonic components in the encoder signals relied upon for position determination. Using position-domain compensation for errors arising in the encoder domain offers computational simplicity and impressive compensation performance, even when compensating for a plurality of higher harmonics in the encoder signals, e.g., third harmonic, fifth harmonic, etc. Consequently, even high-precision position monitoring or control can use relatively inexpensive types of encoders known to output encoder signals having significant harmonic components.
Identify and summarize the most critical technical features from the given patent document.
[ "RELATED APPLICATIONS [0001] This application claims priority from the U.S. provisional application filed on 31 Mar. 2016 and assigned application No. 62/316,251, which application is incorporated herein by reference.", "TECHNICAL FIELD [0002] The present invention generally relates to position encoders and particularly relates to compensating for errors arising from harmonic components present in position encoder signals.", "BACKGROUND [0003] A sinusoidal encoder outputs a pair of sinusoidal signals in quadrature phase relationship, with distance covered over one signal cycle of the encoder being referred to as one “line”", "of the encoder.", "The term “sinusoid”", "is used loosely in this context because some encoders, particularly less expensive encoders, output only rough approximations of sinusoids, or otherwise output sinusoids with significant harmonic components in addition to the fundamental frequency component.", "[0004] A coarse physical position (“position”) may be tracked by a running count of the signal cycles over multiple lines of the encoder, and much finer incremental positions may be tracked within each signal cycle via “interpolation.”", "One technique for interpolating the position within each signal cycle relies on the arctangent function, which expresses the incremental or fine position within the current signal cycle as: [0000] ∅ fine = tan - 1  ( V sin V cos ) , [0000] where V sin and V cos are the instantaneous signal values of the quadrature waveforms output by the encoder.", "So-called “encoder interpolators”", "exploit the foregoing angular relationship to provide high-resolution tracking of position within each recurring cycle of a sinusoidal encoder.", "Precision machining and many other motion-control applications require the higher resolutions that can be provided by good encoder interpolators.", "[0005] However, errors in the encoder signals directly affect accuracy in position determination, and this point holds true whether the encoder encodes angular or linear positions of a physical system.", "Merely by way of example, the physical system may be a robotic arm, a machine tool head, or a workpiece holder.", "[0006] Known approaches to compensation for imperfections—errors—in the encoder signals typically operate in the “encoder domain,” which is another way of saying that the corrections are detected and applied with respect to the output signals provided by the encoder in question.", "Consider, for example, the encoder interpolator detailed in U.S. Pat. No. 8,384,570, which patent is incorporated herein by reference and discloses techniques for compensating for fundamental errors in the encoder signals.", "Here, fundamental errors include any one or more of voltage offsets on the encoder signals, magnitude mismatches between the encoder signals, and phase error between the encoder signals.", "The '570 patent provides for such compensation by adjusting the numerical values sampled from the encoder signals.", "[0007] Potentially significant errors in position detection arise because of harmonic components in the encoder signals.", "The encoder signals output from a sinusoidal encoder include a fundamental frequency component, which can be understood as the “desired”", "signal.", "Unfortunately, the encoder signals may also include undesirable harmonic components.", "Known encoder compensation techniques contemplate limited forms of harmonic compensation.", "[0008] U.S. Pat. No. 7,109,900, for example, describes a technique for detecting and compensating the third harmonic component present in encoder signals.", "The disclosed approach operates in the encoder domain and relies on examining the Lissajous patterns resulting from converting the encoder signals—i.e., sine and cosine signals—into corresponding radius and angle values.", "Computational complexity limits the viability of the technique, and that complexity especially discourages extension of the technique to higher harmonic components of the fundamental frequency.", "SUMMARY [0009] Methods and apparatus disclosed herein implement or otherwise embody a technique that compensates for cyclic position errors in encoder-based position detection, wherein the cyclic position errors arise from the presence of harmonic components in the encoder signals relied upon for position determination.", "Using position-domain compensation for errors arising in the encoder domain offers computational simplicity and impressive compensation performance, even when compensating for a plurality of higher harmonics in the encoder signals, e.g., third harmonic, fifth harmonic, etc.", "Consequently, even high-precision position monitoring or control can use relatively inexpensive types of encoders known to output encoder signals having significant harmonic components.", "[0010] In an example embodiment, a method of encoder interpolation includes receiving encoder signals from a sinusoidal encoder, sampling the encoder signals to obtain sampled signal values, calculating positions from the sampled signal values, obtaining corrected positions by applying corresponding correction values to the calculated positions, and forming extended positions comprising the corrected positions and a current cycle count associated with the encoder signals.", "The method further includes determining position errors between the extended positions and corresponding estimated positions, as estimated by a digital state estimator that constrains position estimation according to a mathematical model of a physical system whose position is being tracked by the sinusoidal encoder, and outputting the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of a physical system.", "[0011] Still further, the method includes determining the correction values by processing the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors, and determining the correction values as a function of the determined magnitudes.", "Such processing will be understood as detecting and correcting—compensating for—cyclic position errors in the “position”", "domain, which offers significant computational efficiency as compared to detecting and correcting encoder errors in the encoder signals.", "[0012] In another example embodiment, an encoder interpolator includes input circuitry configured to receive encoder signals from a sinusoidal encoder and sample the encoder signals to obtain sampled signal values, and processing circuitry configured to calculate positions from the sampled signal values, obtain corrected positions by applying corresponding correction values to the calculated positions, and form extended positions comprising the corrected positions and a current cycle count associated with the encoder signals.", "The encoder interpolator further includes output circuitry configured to output the extended positions or a filtered version thereof, for use in monitoring or controlling the position of a physical system.", "[0013] Within the above processing framework, the processing circuitry is configured to determine position errors between the extended positions and corresponding estimated positions, as estimated by an included digital state estimator that constrains position estimation according to a mathematical model of a physical system whose position is being tracked by the sinusoidal encoder.", "Further, to determine the correction values, the processing circuitry is configured to process the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors, and determine the correction values as a function of the determined magnitudes.", "[0014] Of course, the present invention is not limited to the above features and advantages.", "Those of ordinary skill in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a block diagram of one embodiment of an encoder interpolator.", "[0016] FIG. 2 is a logic flow diagram of a method of encoder interpolation.", "[0017] FIG. 3 is a block diagram of one embodiment of processing circuitry configured for encoder interpolation.", "DETAILED DESCRIPTION [0018] FIG. 1 depicts a sinusoidal encoder 8 that is used to track the position of a physical system.", "The position information is encoded in its output signals, which are at least nominally a pair of analog sinusoids in quadrature relationship.", "An encoder interpolator 10 receives the encoder signals and processes them for monitoring or controlling the position of the physical system.", "Movement of the physical system may be linear or angular, or a combination of linear and angular movement, and the encoder signals may encode linear or angular position.", "[0019] The encoder interpolator 10 includes interface circuitry 12 , which includes input circuitry 14 and output circuitry 16 .", "Further included in the example implementation are processing circuitry 20 , which includes or otherwise implements a digital state estimator 22 , and which includes or is associated with storage 24 .", "The storage 24 in one or more embodiments stores a data structure or set of parameters comprising a mathematical model of the physical system 26 , for use by the digital state estimator 22 , which uses the system model to estimate positions in correspondence with processing the encoder signals incoming to the encoder interpolator 10 .", "It is also possible for the mathematical model 26 to be incorporated or otherwise hard-coded in the digital state estimator 22 .", "[0020] In at least some embodiments, the storage 24 stores a computer program 28 comprising program instructions that, when executed by a processor, e.g., a microprocessor, within the encoder interpolator 10 , causes the encoder interpolator 10 to operate as described herein.", "Thus, in at least one embodiment, the processing circuitry 20 is realized at least in part by executing computer instructions in one or more processing circuits.", "More generally, the processing circuitry 20 may be fixed circuitry, programmable circuitry, or a mix of both fixed and programmable circuitry.", "Correspondingly, the storage 24 in such embodiments comprises one or more types of computer-readable media, such as volatile working memory and non-volatile program memory.", "Non-limiting examples include any one or more of FLASH, EEPROM, DRAM, and SRAM memory circuits or devices.", "However implemented, the storage 24 may also store various configuration data 30 for the processing circuitry 20 .", "[0021] With a focus on explaining its operational configuration, the example encoder interpolator 10 comprises input circuitry 14 configured to receive encoder signals from a sinusoidal encoder 8 and sample the encoder signals to obtain sampled signal values.", "Further, the encoder interpolator 10 includes processing circuitry 20 that is configured to calculate positions from the sampled signal values, obtain corrected positions by applying corresponding correction values to the calculated positions, form extended positions comprising the corrected positions and a current cycle count associated with the encoder signals, determine position errors between the extended positions and corresponding estimated positions, as estimated by the included digital state estimator 22 that constrains position estimation according to a mathematical model of the physical system whose position is being tracked by the sinusoidal encoder 8 .", "The encoder interpolator 10 further includes output circuitry 16 configured to output the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of the physical system.", "[0022] To determine the correction values, the processing circuitry 20 is configured to process the position errors on a running basis to determine the magnitude of one or more harmonic components of the position errors.", "Correspondingly, the processing circuitry 20 is configured to determine the correction values as a function of the determined magnitudes.", "In an example implementation, the processing circuitry 20 is configured to process the position errors on a running basis by performing Fourier-transform processing of the position errors for one or more specific frequencies corresponding to one or more harmonic components for which correction is desired.", "Limiting the processing to specific frequencies of interest greatly simplifies the associated processing, as compared to performing a Fourier transform over a larger range of frequencies.", "[0023] The sampling of the input signals, and subsequent processing of the sampled values, including position calculation, digital state estimation, error identification, and position correction, must all operate at a discrete frequency high enough to occur multiple times per the highest position error harmonic to be detected at the maximum physical frequency for which detection is desired.", "This is a consequence of the well-known Nyquist sampling theorem, which states that such sampling must occur more than twice per cycle of the highest frequency component to be detected.", "In practice, this means that such sampling and processing must occur at multiple megahertz for typical real-world systems.", "[0024] More broadly, in one or more embodiments, the processing circuitry 20 is configured to determine the magnitudes of a limited number of harmonic components of the position errors, including at least the fourth harmonic and one or more higher even harmonics.", "Here, it will be appreciated that odd harmonic components in the encoder signals are manifested as even harmonic components in the position errors.", "For example, a third harmonic component of the fundamental frequency of the encoder signals results in a fourth harmonic component in the position errors.", "[0025] Thus, it will be appreciated that the processing circuitry 20 is configured to correct for at least one harmonic component of the position errors and, preferably, is configured to compensate for a fourth harmonic component of the position errors and one or more higher even harmonic components of the position errors.", "To do so, the processing circuitry 20 is configured to determine the sign and magnitude of the one or more harmonic components of the position errors by calculating coefficients representing the magnitude of sine or cosine components of each harmonic component among the one or more harmonic components of the position errors.", "When the phrase “sine or cosine”", "is used herein, and unless otherwise noted or apparent from the context, it shall be understood being one or the other, or both.", "For example, stating that the processing circuitry 20 determines sine or cosine components of a harmonic component of the position errors shall be understood as saying that the processing circuitry 20 may determine either sine or cosine components, or both sine and cosine components.", "[0026] As for determining the correction values applied to the positions computed from the encoder signals, the processing circuitry 20 in one or more embodiments is configured to determine the correction values as a function of the determined magnitudes of the sine or cosine components of each harmonic component of the position errors that is being corrected.", "The processing circuitry 20 does so by, for each calculated position value and each harmonic component of the position errors being corrected, multiplying the calculated position by a multiplier corresponding to the harmonic component being corrected and taking the sine or cosine of the result, and taking the result of the sine or cosine operation and multiplying it by the corresponding coefficient.", "[0027] In addition to correcting for position errors in the “position domain,” the processing circuitry 20 may be configured to compensate the sampled signal values obtained from the encoder signals for at least one of: signal offsets of the encoder signals, magnitude mismatch of the encoder signals, and quadrature phase error of the encoder signals.", "Such processing improves the sampled signaled values used by the processing circuitry 20 for initial computation of position from the encoder signals, meaning that the corrected positions reflect both compensation for fundamental errors in the encoder signals, as well as compensation for higher-order errors, e.g., third, fifth, and seventh harmonic components.", "However, it shall be understood that the compensation for higher-order errors in the encoder signals occurs not in the “encoder domain”", "but rather in the position domain as noted above.", "Here, the term “position domain”", "denotes the detection of cyclic position errors and the correction of those errors, based on processing the positions calculated from the encoder signals.", "[0028] In one or more embodiments, the encoder interpolator 10 is a component of a larger apparatus, e.g., a motion controller that uses the extended positions determined by the encoder interpolator 10 for its motion-control algorithms.", "More generally, the encoder interpolator 10 is used in association with monitoring or controlling the position of a physical system and in at least some embodiments includes output circuitry 16 that is configured to output the extended positions or filtered extended positions to a controlling or monitoring apparatus, as numerical values provided in a serial or a parallel format.", "The processing circuitry 20 or the output circuitry 16 may also be configured to generate and output a digital quadrature signal and corresponding digital sine and cosine signals, corresponding to the encoder signals but compensated for the cyclic position errors detected and corrected for by the processing circuitry 20 .", "In other words, the encoder interpolator 20 may be configured to output a recreation of the encoder signals—in the digital domain—from which one or more cyclic position errors are removed.", "[0029] The encoder interpolator 10 in at least some embodiments provides other useful signals as outputs.", "For example, in operation, the digital state estimator 22 estimates acceleration from the position errors, integrates the acceleration estimates to obtain velocity estimates, and integrates the velocity estimates to obtain position estimates.", "Advantageously, in one or more embodiments, the output circuitry 16 is configured to output the estimates of acceleration and velocity from the digital state estimator 22 , for use as system feedback states by an associated positioning monitoring or control apparatus.", "Conventionally, such estimates would remain internal to the state estimation process.", "[0030] FIG. 2 illustrates one embodiment of a method 200 of encoder interpolation, which may be carried out by the encoder interpolator 10 of FIG. 1 , or which may be carried out using any suitable arrangement of processing circuitry.", "The method 200 shall be understood as a running process that executes repeatedly within and over cycles of the encoder 8 .", "[0031] The method 200 includes receiving (Block 202 ) encoder signals from a sinusoidal encoder 8 , sampling (Block 204 ) the encoder signals to obtain sampled signal values, calculating (Block 206 ) positions from the sampled signal values, obtaining (Block 208 ) corrected positions by applying corresponding correction values to the calculated positions, forming (Block 210 ) extended positions comprising the corrected positions and a current cycle count associated with the encoder signals, and outputting (Block 212 ) the extended positions, or a filtered version thereof, for use in monitoring or controlling the position of physical system.", "[0032] The method 200 further includes, e.g., in a running feedback loop arrangement, determining (Block 214 ) the position errors between the extended positions and corresponding estimated positions, as generated by the digital state estimator 22 .", "The position errors are used for determining (Block 216 ) the correction values.", "[0033] The determining step 216 comprises a “running”", "process within the larger set of ongoing operations and it includes processing (Block 218 ) the position errors on a running basis to determine the sign and magnitude of one or more harmonic components of the position errors, and determining (Block 220 ) the correction values as a function of the determined magnitudes.", "That is, each newly determined position error feeds into the error-correction process.", "[0034] The method 200 provides numerous advantages.", "For example, in the most exacting motion control applications involving the use of high-quality encoders that are already quite good, the compensation of cyclic position errors provides for even higher precision.", "Further, the method 200 may make it feasible to use lower-quality encoders in at least some applications that would otherwise require more expensive encoders with less harmonic content in their output encoder signals.", "[0035] On that point, it is common for analog quadrature encoders, even those marketed as “sinusoidal”", "encoders, to have substantial odd-harmonic content, notably in the third, fifth, seventh, and ninth harmonics.", "These signal harmonics produce predictable higher even-harmonic position errors in any encoder interpolator that does not compensate for these higher-order harmonics in the encoder signals.", "For example, matching the third-harmonic component in both encoder signals—i.e., in the quadrature sinusoids output by the encoder—yields cyclic position errors of 4th, 8th, 12th, 16th etc.", "harmonics of the fundamental signal frequency (the encoder cycle frequency) in any encoder interpolator that lacks the ability to correct for higher-order harmonics in the encoder signals.", "[0036] If a given harmonic component in the encoder signals is of fraction x of the fundamental signal component, the resulting position error (in radians of a line cycle) can be expressed as: [0000] E = x 1 1  sin   4   θ + x 2 2  sin   8   θ + x 3 3  sin   12   θ + x 4 4  sin   16   θ + … [0037] For example, with x=0.05, the 4th-harmonic component of the position error has a magnitude of 0.05 radians, or 2.86 degrees, of a line cycle, and the 8th-harmonic component has a magnitude of 0.00125 radians, or 0.07 degrees.", "[0038] Similarly, the position errors resulting from a matching 5th-harmonic signal component in the encoder signals can be expressed as: [0000] E = x 1 1  sin   4   θ - x 2 2  sin   8   θ + x 3 3  sin   12   θ - x 4 4  sin   16   θ + … [0039] Matching 7th-harmonic signal components in the encoder signals yield errors of: [0000] E = x 1 1  sin   8   θ + x 2 2  sin   16   θ + x 3 3  sin   24  θ + x 4 4  sin   32   θ + … [0040] Matching 9th-harmonic signal components in the encoder signals yield errors of: [0000] E = x 1 1  sin   8   θ - x 2 2  sin   16   θ + x 3 3  sin   24   θ - x 4 4  sin   32   θ + … [0041] If the only signal errors in the encoder signals are matching odd harmonics, the resulting position errors are independent and superimposable, with only sin(4N*θ) components.", "However, if there are fundamental signal errors as well (e.g., quadrature errors, magnitude mismatch, etc.), or if the harmonic component magnitudes are not the same between the sine and cosine signals output from the encoder, there can be cosine position error components as well, and with frequencies of 2N*θ as well.", "The techniques disclosed herein provide for detection and correction of all such errors.", "[0042] FIG. 3 depicts one implementation of the encoder interpolator 10 introduced in FIG. 1 .", "The depicted arrangement provides for robust and automatic detection and correction of cyclic position errors arising from higher harmonic components in the encoder signals input to the encoder interpolator 10 for processing.", "Certain circuitry depicted in the diagram, such as the sampling circuitry 40 , may be implemented in the interface circuitry 12 of the encoder interpolator 10 .", "More generally, however, the various computational circuits shall be understood as elements of the overall processing circuitry 20 shown in FIG. 1 .", "[0043] Analog signals from the encoder 8 (which are at least nominally quadrature sinusoids) are digitized in the sampling circuitry 40 , to produce sampled signal values corresponding to the analog signals.", "The sampling circuitry 40 may include other conditioning, such as input signal filtering, etc.", "In any case, processing downstream from the sampling circuitry 40 shall be understood as involving digital values unless otherwise noted.", "[0044] The arctangent calculation circuit 42 converts the digitized sine and cosine signals into an uncorrected angle within one line of the encoder 8 .", "It will be appreciated that such operation is carried out on a “running”", "basis and that the arctangent calculation circuit 42 repeatedly computes line angles during live operation—i.e., multiple line angles are computed within each recurring cycle of the encoder 8 .", "These line angles may also be referred to as “positions.”", "Each such position is a digital value representing the instantaneous angle θ, i.e., the measured phase of the encoder signals.", "The measured phase will exhibit cyclic errors—cyclic position errors—corresponding to higher-order harmonic components in the encoder signals.", "[0045] Via a combining circuit 44 , each position is combined with a corresponding correction value that compensates for one or more cyclic position errors arising from one or more corresponding harmonic components in the encoder signals.", "The correction value applied to each position may comprise a composite or combination of values—e.g., correcting for various sine or cosine components of the position error harmonics.", "[0046] The resulting corrected positions—also referred to as corrected line angles or corrected phase measurements—are “extended”", "via the extension circuit 46 into so called “extended positions.”", "Each extended position comprises a corrected position and a running cycle count that reflects the current cycle count of the encoder signals.", "That is, the corrected position is an instantaneous phase measured within one line of the encoder 8 and the running cycle count is an accumulated count of encoder cycles.", "A given position together with the running cycle count represents an absolute position and the extended positions are, therefore, absolute positions that are compensated for cyclic position errors.", "[0047] The extended positions and/or position errors derived therefrom are fed into the digital state estimator 22 , which comprises circuitry that is configured to use a simplified model of the physical system associated with the encoder 8 —e.g., it uses the mathematical model 26 .", "Because the mathematical model 26 of the physical system does not model or provide for movement frequencies higher than are realistically possible for the physical system, the digital state estimator 22 effectively acts as a low pass filter.", "Given that the position errors produced by signal harmonics in the encoder signals are at very high temporal frequencies at all but the lowest speeds of the encoder, the operation of the digital state estimator 22 is not very sensitive to the values of the system model constants chosen, especially if the cyclic error determination algorithm is only activated above a minimum velocity threshold.", "[0048] In any case, the operative point here is that the high-frequency errors between the extended positions and the corresponding estimated positions as produced by the digital state estimator 22 can be attributed to measurement errors because the physical system cannot truly operate at such frequencies.", "In the diagram, a difference circuit 48 outputs position errors based on taking the difference between each estimated position and the corresponding extended position.", "Here, “corresponding”", "denotes the extended and estimated positions corresponding to the same line angle or position.", "[0049] In this regard, it may be helpful to remember that each extended position comprises a running cycle count and a corrected position, i.e., a corrected angle or phase value θ′ m representing an instantaneous measured phase within one line of the encoder mark, where the accent mark indicates that θ′ m is the corrected version of the corresponding measured value θ m output from the arctangent calculation circuit 42 .", "In the same fashion, the estimated position generated by the digital state estimator 22 in correspondence with each extended position comprises a running cycle count and an estimated instantaneous position θ e that nominally matches the θ′ m term in the corresponding extended position.", "[0050] The difference circuit 48 determines position errors by taking the “difference”", "between each estimated position output from the digital state estimator 22 and the corresponding extended position output from the extension circuit 46 .", "In particular, the error that is of interest is the difference in instantaneous phase angles, i.e., the difference between the θ′ m term of the extended position and the θ e term of the corresponding estimated position.", "The phase angle difference may be denoted as Δθ e .", "Now, it may happen that the running cycle count maintained by the digital state estimator circuit 22 and the running cycle count used by the extension circuit 46 do not roll over at precisely the same instant, and it will be understood that the difference circuit 48 accounts for any rollover discrepancies when determining the difference between the θ′ m and θ e terms of the respective extended and estimated positions.", "[0051] The position errors Δθ e are fed into the adaptive signal harmonic error identification circuit 54 , which looks for patterns in the position errors.", "As a non-limiting example, the circuit 54 shown in the diagram is configured to determine error magnitudes for the 4th, 8th, 12th, and 16th harmonics of the position errors, but other components are possible.", "The error identification in one or more embodiments is done through a Fourier transform algorithm.", "With only specific frequencies being examined, the processing is much simpler than performing a “continuous”", "transform.", "In other words, the circuit 54 can be preconfigured to determine the magnitudes of only certain, predefined harmonic components.", "For example, the circuit 54 may be configured to generate magnitude coefficients corresponding to only the 4th, 8th, and 12th harmonic components in the position errors, meaning that it need only perform processing corresponding to these preconfigured harmonic components.", "[0052] In the diagram, the “K”", "coefficients output from the adaptive signal harmonic error identification circuit 54 are coefficients for the sine or cosine components of the 4th, 8th, 12th, and 16th harmonic components of the position errors, e.g., as determined via Fourier-transform processing on a running series of position errors Δθ e .", "[0053] On a running basis, the error coefficients calculated by the circuit 54 are multiplied in a sine lookup table circuit 56 using values dependent on the instantaneous angle within an encoder line θ e multiplied by the appropriate harmonic factor N. The resulting products are combined to obtain an overall instantaneous error value—referred to in the diagram as a “CORRECTION VALUES.”", "Thus, a correction value is subtracted from each instantaneous measured position θ m to obtain the corresponding corrected position θ′ m .", "Notably, while correction for the sine components of the 4th, 8th, 12th, and 16th harmonics is explicitly shown in the diagram (i.e. K 4 sin 4θ terms and so on), the processing circuitry 20 in one or more embodiments implements a cosine lookup table circuit 58 , and the adaptive signal harmonic identification circuit 54 additionally generates magnitude coefficients corresponding to the cosine component of the position-error harmonics being corrected.", "These cosine-component magnitude coefficients are used by the cosine lookup table circuit 58 to generate correction values for the cosine components and all such correction values are included in the combining operation used to form the correction value to be subtracted from the current position.", "[0054] With the cyclic error identification and correction algorithm described above always running (or at least always running above a minimum velocity threshold), the encoder interpolator 10 continuously adapts to error patterns that change over position and time.", "This operation in turn permits high-accuracy results from encoders that are less expensive to make and to install.", "Note that the most recently determined corrections may continue to be used even when operating below the minimum velocity threshold.", "[0055] Configuring which error components are detected and removed by the encoder interpolator reflects various tradeoffs in performance versus complexity.", "The error components that tend to be the largest are the most important to remove.", "The higher the harmonic in the encoder signal, the lower the corresponding magnitude of position-error harmonic tends to be.", "For each harmonic component in the encoder signals, the secondary, and especially tertiary, position-error components are significantly smaller than the primary.", "As a further consideration, it is noted herein that the cosine components from interactions tend to be smaller than the sine components.", "[0056] The processing circuitry 20 may output the extended positions directly, or may output a filtered version of the extended positions, such as provided for in the diagram via the moving average filter circuit 50 .", "There, one sees that the filter circuit 50 outputs filtered extended positions (“FiltExtPos”), for use in position monitoring or control.", "[0057] In at least some embodiments, the processing circuitry 20 further provides for regeneration of the quadrature encoder signals, which occurs in the digital domain and provides the advantage of generating encoder signals corresponding to the received encoder signals but minus the cyclic position errors corrected by the processing circuitry 20 .", "Such operations are provided for in the sine/cosine calculation circuit 52 , which outputs a digital quadrature signal (“FiltCorrABquad”) that it derives from the filtered extended positions.", "The circuit 52 further outputs filtered sinusoids in quadrature (“FiltCorrSine”", "and “FiltCorrCosine”) that correspond to the encoder signals minus the harmonic encoder-domain content corresponding to the cyclic position errors canceled by the processing circuitry 20 in the position domain.", "[0058] Still further, the diagram depicts an advantageous implementation of the digital state estimator 22 , such as mentioned earlier.", "Here, the digital state estimator 22 outputs the estimates of acceleration and velocity that it uses for generating the estimated positions.", "These values represent feedback states that a downstream motion controller or other downstream processing circuitry would have to estimate for position monitoring or control of the physical system, and it is therefore computationally efficient to provide them from the digital state estimator 22 .", "The velocity and acceleration values from the high-frequency based estimation performed by the digital state estimator 22 have lower quantization errors and delays than what the downstream controller could compute itself from the position.", "[0059] Finally, at least some embodiments of the processing circuitry 20 additionally compensate for fundamental errors in the encoder signals, and include a fundamental error correction circuit 60 .", "The fundamental error correction circuit 60 operates in the “encoder domain”", "on the encoder signals or the digitized versions thereof, and may be configured according to known techniques to compensate for any one or more of quadrature error in the encoder signals, voltage offsets of the encoder signals, and magnitude mismatch between the encoder signals.", "[0060] Notably, modifications and other embodiments of the disclosed invention(s) will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.", "Therefore, it is to be understood that the invention(s) is/are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of this disclosure.", "Although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation." ]
CROSS-REFERENCE TO RELATED APPLICATION [1] 1. This application is a continuation-in-part of U.S. patent application 08/675,439, filed Jun. 28, 1996. BACKGROUND OF THE INVENTION [2] 2. The Ras family of proteins are important in the signal transduction pathway modulating cell growth. The protein is produced in the ribosome, released into the cytosol, and post-translationally modified. The first step in the series of post-translational modifications is the alkylation of Cys 168 with farnesyl or geranylgeranyl pyrophosphate in a reaction catalyzed by prenyl transferase enzymes such as farnesyl transferase and geranylgeranyl transferase (Hancock, J F, et al., Cell 57:1167-1177 (1989)). Subsequently, the three C-terminal amino acids are cleaved (Gutierrez, L., et al., EMBO J. 8:1093-1098 (1989)), and the terminal Cys is converted to a methyl ester (Clark, S., et al., Proc. Nat'l Acad. Sci. (USA) 85:4643-4647 (1988)). Some forms of Ras are also reversibly palmitoylated on cysteine residues immediately N-terminal to Cys 168 (Buss, J E, et al., Mol. Cell. Biol. 6:116-122 (1986)). It is believed that these modifications increase the hydrophobicity of the C-terminal region of Ras, causing it to localize at the surface of the cell membrane. Localization of Ras to the cell membrane is necessary for signal transduction (Willumsen, B M, et al., Science 310:583-586 (1984)). [3] 3. Oncogenic forms of Ras are observed in a relatively large number of cancers including over 50 percent of colon cancers and over 90 percent of pancreatic cancers (Bos, J L, Cancer Research 49:4682-4689 (1989)). These observations suggest that intervention in the function of Ras mediated signal transduction may be useful in the treatment of cancer. [4] 4. Previously, it has been shown that the C-terminal tetrapeptide of Ras has the “CAAX” motif (wherein C is cysteine, A is an aliphatic amino acid, and X is any amino acid). Tetrapeptides having this structure have been shown to be inhibitors of prenyl transferases (Reiss, et al., Cell 62:81-88 (1990)). Poor potency of these early farnesyl transferase inhibitors has prompted the search for new inhibitors with more favorable pharmacokinetic behavior (James, G L, et al., Science 260:1937-1942 (1993); Kohl, N E, et al., Proc. Nat'l Acad. Sci. USA 91:9141-9145 (1994); deSolms, S J, et al., J. Med. Chem. 38:3967-3971 (1995); Nagasu, T, et al., Cancer Research 55:5310-5314 (1995); Lerner, E C, et al., J. Biol. Chem. 270:26802-26806 (1995); Lerner, E C, et al., J. Biol. Chem. 270:26770 (1995); and James, et al., Proc. Natl. Acad. Sci. USA 93:4454 (1996)). [5] 5. Recently, it has been shown that a prenyl transferase inhibitor can block growth of Ras-dependent tumors in nude mice (Kohl, N E, et al., Proc. Nat'l Acad. Sci. USA 91:9141-9145 (1994)). In addition, it has been shown that over 70 percent of a large sampling of tumor cell lines are inhibited by prenyl transferase inhibitors with selectivity over non-transformed epithelial cells (Sepp-Lorenzino, I, et al., Cancer Research, 55:5302-5309 (1995)). Inhibiting farnesylation has been disclosed as a method of treating hepatitis delta virus infection, (Casey, P, et al., WO 97/31641). SUMMARY OF THE INVENTION [6] 6. In one aspect, the invention features a compound of formula I or formula II [7] 7. wherein [8] 8. R 1 is N(R 10 ) (R 11 ); [9] 9. R 2 is thio lower alkyl; [10] 10. each of R 3 and R 5 , independently, is CH 2 or C(O); [11] 11. R 4 is substituted or unsubstituted thio lower alkyl, [12] 12. wherein said substituent is CH 2 NHC(O)R 13 and said substituent is attached to said thio group; [13] 13. R 6 is a residue of a natural or synthetic α-amino acid; [14] 14. R 7 is a residue of a natural or synthetic α-amino acid; [15] 15. R 8 is OH or lower alkoxy, or, together with R 7 , forms homoserinelactone; [16] 16. each of R 9 , R 10 and R 11 , independently, is H or lower alkyl; [17] 17. R 12 is substituted or unsubstituted cycloalkyl, cycloalkyl lower alkyl, aryl, aryl lower alkyl, heterocycle, or heterocycle lower alkyl, wherein said substituent is lower alkyl, aryl, halo, lower alkoxy, or C(O)—R 7 —R 8 ; [18] 18. R 13 is lower alkyl, aryl, or aryl lower alkyl; [19] 19. R 18 is H or, together with R 9 , forms CH 2 CH 2 ; [20] 20. provided if R 4 is unsubstituted thio lower alkyl, the free thio group of R 2 and the free thio group of R 4 may form a disulfide bond; [21] 21. or a pharmaceutically acceptable salt thereof. [22] 22. In another aspect, the present invention is directed to a process for preparing a compound of Formula I or Formula II. [23] 23. In one embodiment, the compound is of formula I where R 6 is —N(R 14 )CH(R 15 )C(O)—, where R 14 is H or lower alkyl, and R 15 is substituted or unsubstituted lower alkyl, aryl, aryl lower alkyl, heterocycle, or heterocycle lower alkyl where said substituent is lower alkyl, halo, or lower alkoxy, or where R 15 , together with NR 14 C attached thereto, form heterocycle; and R 7 is —N(R 16 )CH(R 17 )C(O)— where R 16 is H or lower alkyl, and R 17 is (CH 2 ) m S(O) n CH 3 or substituted or unsubstituted lower alkyl, thio lower alkyl, where said substituent is C(O)N(R 10 )(R 11 ), m is 1-6, n is 0-2, and R 8 is OH or lower alkoxy. In this embodiment, R 2 can be CH 2 SH; R 4 can be C(CH 3 ) 2 SH or CH 2 SH wherein the free thio group of R 2 and the free thio group of R 4 form a disulfide bond; R 15 , together with NR 14 C attached thereto, can form heterocycle; R 16 can be H; and R 17 can be (CH 2 ) 2 S(O) n CH 3 ; furthermore, R 1 can be NH 2 ; R 3 can be CH 2 ; R 5 can be CO; and R 8 can be OH or OCH 3 . In the same embodiment, R 2 can be (CH 2 )SH; R 4 can be C(CH 2 ) 2 SCH 2 NHCOCH 3 or CH 2 SCH 2 NHCOCH 3 ; R 15 , together with NR 14 C attached thereto, can form heterocycle; R 16 can be H, and R 17 can be (CH 2 ) 2 S(O) n CH 3 ; furthermore, R 1 is NH 2 ; R 3 is CH 2 ; R 5 is C(O); and R 8 is OH or OCH 3 . [24] 24. In another embodiment, the compound is of formula II, wherein R 2 is CH 2 SH; R 4 is C(CH 3 ) 2 SH or CH 2 SH wherein the free thio group of R 2 and the free thio group of R 4 form a disulfide bond; R 12 is substituted or unsubstituted aryl or is aryl lower alkyl, and R 18 is H. In this embodiment, R 1 can be NH 2 ; R 3 can be CH 2 ; R 5 can be C(O); R 9 can be H; and R 12 can be substituted or unsubstituted phenyl or benzyl, wherein said substituent is lower alkyl or halo. [25] 25. In a still further embodiment, R 2 is (CH 2 )SH; R 4 is C(CH 2 ) 2 SCH 2 NHCOCH 3 or CH 2 SCH 2 NHCOCH 3 ; and R 12 is subsitituted or unsubstituted aryl or aryl lower alkyl. In this embodiment, R 1 can be NH 2 ; R 3 can be CH 2 ; R 5 can be CO; R 9 can be H; and R 12 can be substituted or unsubstituted phenyl or benzyl, wherein said substituent is lower alkyl or halo. [26] 26. Examples of the present invention include the following: [27] 27. In another aspect, the invention features a compound of formula III or formula IV [28] 28. where [29] 29. Y is CH 2 or C(O); [30] 30. R 1 , R 2 , R 3 , and R 4 , each is, independently, H, lower alkyl, optionally substituted arylalkyl, optionally substituted alkenyl, (C 1 -C 18 )-aliphatic acyl, or arylacyl; [31] 31. R 5 and R 6 each is, independently, H or CH 3 ; [32] 32. R 9 and R 10 each is independently selected from the group consisting of H, lower alkyl, and C 3 -C 6 cycloalkyl; [33] 33. Ar is optionally substituted aryl or optionally substituted heterocycle; [34] 34. n is 0 or an integer from 1 to 4; [35] 35. wherein each substituent is, independently, aryl, heterocycle, halogen, OR 9 , NR 9 R 10 , CN, NO 2 , CF 3 , or lower alkyl, said lower alkyl optionally substituted with C 1 -C 4 alkoxy, NR 9 R 10 , C 3 -C 6 cycloalkyl, or OH; [36] 36. or a pharmaceutically acceptable salt thereof. [37] 37. In still another aspect, the present invention is directed to a process for preparing a compound of Formula III or Formula IV. [38] 38. A preferred group of compounds of Formula III or Formula IV include the following: [39] 39. In yet another aspect, the invention features a compound of formula V: [40] 40. wherein [41] 41. Ar is optionally substituted aryl or optionally substituted heterocycle, wherein each substituent is independently selected from the group consisting of aryl, heterocycle, halogen, OR 9 , NR 9 R 10 , CN, NO 2 , CF 3 , and lower alkyl, said lower alkyl optionally substituted with (C 1 -C 4 )-alkoxy, NR 9 R 10 , C 3 -C 6 cycloalkyl, or OH; [42] 42. R 1 and R 2 each is, independently, CH 2 or C(O); [43] 43. R 3 and R 4 each is, independently, H or CH 3 ; [44] 44. R 5 , R 6 , R 7 , and R 8 each is independently selected from the group consisting of H, or an optionally substituted moiety selected from the group consisting of (C 1 -C 8 )-alkyl, alkenyl, alkynyl, aryl, and heterocycle; [45] 45. wherein said optionally substituted moiety is optionally substituted by one or more substituents independently selected from the group consisting of (C 3 -C 6 ) -cycloalkyl, optionally further substituted aryl, and optionally further substituted heterocycle, [46] 46. wherein said optionally further substituted aryl and heterocycle are optionally substituted by one or more substituents independently selected from the group consisting of (C 1 -C 4 )-alkyl, halogen, (CH 2 ) m OR 9 , and (CH 2 ) m NR R 10 ; [47] 47. R 9 and R 10 each is, independently, H lower alkyl or (C 3 -C 6 ) cycloalkyl; [48] 48. R 11 is H or NH 2 ; [49] 49. m is 0 or an integer from 1 to 4; [50] 50. n is 0, 1, or 2; [51] 51. or a pharmaceutically acceptable salt thereof. [52] 52. In another aspect, the present invention is directed to a process for preparing a compound of Formula V. [53] 53. A preferred group of compounds of Formula V includes the following: [54] 54. The compounds of the present invention may have asymmetric centers and occur as racemates, racemic mixtures, and as individual diastereomers, with all possible isomers, including optical isomers, being included in the present invention. For simplicity, where no specific configuration is depicted in a structural formula, it is understood that all enantiomeric forms and mixtures thereof are represented. [55] 55. As used herein, “lower alkyl” is intended to include saturated aliphatic hydrocarbon groups having 1-6 carbon atoms. Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, and the like. The term “alkyl” refers to saturated aliphatic hydrocarbon groups having up to 18 carbon atoms. The terms “alkenyl” and “alkynyl” refer to unsaturated aliphatic hydrocarbon groups having 2-18 carbon atoms and from 1 to 5 double or triple bonds. “Lower alkoxy” groups include those groups having 1-6 carbons. Examples of lower alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, and the like. All alkyl, alkenyl, alkynyl and alkoxy groups may be branched or straight chained, but are noncyclic. The term “cycloalkyl” means a 3-7 carbon ring. Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloseptyl. The term “halo” means chloro, bromo, iodo, or fluoro. The terms “heterocycle lower alkyl,” “thio lower alkyl,” “cycloalkyl lower alkyl”, and “lower alkyl,” are substituted, respectively, with one to three heterocycle, thio, cycloalkyl, and aryl groups. [56] 56. As used herein, “aryl” is intended to include any stable monocyclic, bicyclic, or tricyclic carbon ring(s) of up to 7 members in each ring, wherein at least one ring is aromatic. Examples of aryl groups include phenyl, naphthyl, anthracenyl, biphenyl, tetrahydronaphthyl, indanyl, phenanthrenyl, and the like. [57] 57. The term heterocycle, as used herein, represents a stable 5- to 7-membered monocyclic or stable 8- to 11-membered bicyclic or stable 11 to 15-membered tricyclic heterocyclic ring which is either saturated or unsaturated, and which consists of carbon atoms and from one to four heteroatoms selected from the group consisting of N, O, and S, and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The heterocyclic ring may be attached at any heteroatom or carbon atom which results in the creation of a stable structure. Examples of such heterocyclic elements include, but are not limited to, azepinyl, benzimidazolyl, benzisoxazolyl, benzofurazanyl, benzopyranyl, benzothiopyranyl, benzofuryl, benzothiazolyl, benzothienyl, benzoxazolyl, chromanyl, cinnolinyl, dihydrobenzofuryl, dihydrobenzothienyl, dihydrobenzothiopyranyl, dihydrobenzothio-pyranyl sulfone, furyl, imidazolidinyl, imidazolinyl, imidazolyl, indolinyl, indolyl, isochromanyl, isoindolinyl, isoquinolinyl, isothiazolidinyl, isothiazolyl, isothiazolidinyl, morpholinyl, naphthyridinyl, oxadiazolyl, 2-oxoazepinyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolidinyl, piperidyl, piperazinyl, pyridyl, pyridyl N-oxide, quinoxalinyl, tetrahydrofuryl, tetrahydroisoquinolinyl, tetrahydro-quinolinyl, thiamorpholinyl, thiamorpholinyl sulfoxide, thiazolyl, thiazolinyl, thiazolidinyl, thienofuryl, thienothienyl, thienyl, and the like. [58] 58. When a group is substituted, it may be substituted one to four times. The various substituents may be attached to carbon atoms or to heteroatoms (e.g., S, N, or O). [59] 59. As used herein, the term “residue of an α-amino acid” stands for an α-amino acid residue which is either a natural α-amino acid which is found in nature (e.g., cysteinyl, methionyl, phenylalaninyl, leucinyl, etc.) or a synthetic α-amino acid which is not found in nature (e.g., neurleucyl or the residue of 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid or penicillamine, etc.). [60] 60. The compounds of this invention can be provided in the form of pharmaceutically acceptable salts. Acceptable salts include, but are not limited to acid addition salts of inorganic acids such as acetate, maleate, fumarate, tartrate, succinate, citrate, lactate, methanesulfonate, p-toluenesulfonate, pamoate, salicylate, oxalate, and stearate. Also within the scope of the present invention, where applicable, are salts formed from bases such as sodium or potassium hydroxide. For further examples of pharmaceutically acceptable salts see, “Pharmaceutical Salts,” J. Pharm. Sci. 66:1 (1977). [61] 61. In another aspect, the invention features a method of inhibiting prenyl transferases (e.g., farnesyl transferase or geranylgeranyl transferase) in a subject, e.g., a mammal such as a human, by administering to the subject a therapeutically effective amount of a compound of formula I, formula II, formula III, formula IV, or formula V. In particular, the present invention also covers a method of treating restenosis or tissue proliferative diseases (i.e., tumor) in a subject by administering to the subject a therapeutically effective amount of a compound or its salt. Examples of a tissue proliferative disease include both those associated with benign (e.g., non-malignant) cell proliferation such as fibrosis, benign prostatic hyperplasia, atherosclerosis, and restenosis, and those associated with malignant cell proliferation, such as cancer (e.g., ras-mutant tumors). Examples of treatable tumors include breast, colon, pancreas, prostate, lung, ovarian, epidermal, and hematopoietic cancers (Sepp-Lorenzino, I, et al., Cancer Research 55:5302 (1995)). [62] 62. A therapeutically effective amount of a compound of this invention and a pharmaceutically acceptable carrier substance (e.g., magnesium carbonate, lactose, or a phospholipid with which the therapeutic compound can form a micelle) together form a pharmaceutical composition (e.g., a pill, tablet, capsule, or liquid) for administration (e.g., orally, intravenously, transdermally, or subcutaneously) to a subject in need of the compound. The pill, tablet, or capsule can be coated with a substance capable of protecting the composition from the gastric acid or intestinal enzymes in the subject's stomach for a period of time sufficient to allow the composition to pass undigested into the subject's small intestine. [63] 63. The compounds of the present invention may be administered in a dosage range of about 0.0001 to 200 mg/kg/day, preferably 0.01 to 100 mg/kg/day. A dose of a compound of the present invention for treating the above-mentioned diseases or disorders varies depending upon the manner of administration, the age and the body weight of the subject, and the condition of the subject to be treated, and ultimately will be decided by the attending physician or veterinarian. Such an amount of the compound as determined by the attending physician or veterinarian is referred to herein as a “therapeutically effective amount.” [64] 64. Also contemplated within the scope of the invention are a method of preparing the compounds of formula I, formula II, formula III, formula IV, and formula V, and the novel chemical intermediates used in these syntheses as described herein. [65] 65. Other features and advantages of the present invention will be apparent from the detailed description of the invention and from the claims. DETAILED DESCRIPTION OF THE INVENTION [66] 66. It is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent. The following specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever. [67] 67. A compound of the present invention can be tested for farnesyl transferase inhibiting activity by testing said compound in a farnesyl transferase in vitro assay, such as the assay described below. [68] 68. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Also, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference. [69] 69. Farnesyl transferase activity is assayed by [ 3 H] farnesylation of recombinant human H-Ras protein wild type, using microplate and filtration method. Incubation mixture contains, in a total volume of 25 μl: 50 mM Tris HCl (pH 7.5), 5 mM dithiothreitol, 20 μM ZnCl 2 , 40 mM MgCl 2 , 0.6 μM [ 3 H] farnesyl pyrophosphate (22.3 Ci/mmol), 4 μM H-Ras and 10 μg of farnesyl transferase from human brain cytosol. Test compounds are added in adequate solvent and incubations start by addition of farnesyl transferase. After approximately 60 minutes at approximately 37° C., the reaction is stopped by addition of 100 μl of 10% HCl in ethanol and allowed to incubate approximately 15 minutes at approximately 37° C., then 150 μl of absolute ethanol are added and incubation mixture is filtered on Unifilter GF/B microplates and washed 6 times with ethanol. After addition of 50 μl of Microscint 0, plates were counted on a Packard Top Count scintillation counter. Geranylgeranyl transferase activity is assayed by the same method, but using 4 μM human recombinant H-Ras CVLL type, 0.6 μM [ 3 H] geranylgeranyl-pyrophosphate (19.3 Ci/mmmol) and 100 μg of geranylgeranyl transferase from human brain. [70] 70. The following is a description of the synthesis of compounds 1, 4, 9. Compounds 2,3,5-8, 10-20 can be prepared in an analogous manner by a person of ordinary skill in the art using appropriate starting materials. Compounds 21, 28, 29, and 30 were prepared using the reactions summarized in reaction scheme I. Compound 22 was prepared using the reactions summarized in reaction schemes II and IV. Compounds 25, 26, and 27 were prepared using the reactions summarized in reaction scheme V. Compound 31 may be prepared using the reactions summarized in scheme III. Other compounds of the invention can be prepared in an analogous manner by a person of ordinary skill in the art using appropriate starting materials. [71] 71. The compounds of the invention were prepared using standard solution phase methodologies, e.g., as described in Greenstein, et al., Chemistry of the Amino Acids, Vols. 1-3 (J. Wiley, New York (1961)); and M. Bodanszky, et al., The Practice of Peptide Synthesis (Springer-Verlag, 1984)). The condensation reactions were carried out in an inert organic solvent, e.g., dimethylformide, dichloromethane, tetrahydrofuran, benzene or acetonitrile, using a suitable mild condensing agent, e.g., 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide-HCl (EDC), 0-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU), and optionally a catalyst, e.g., 1-hydroxybenzotriazole (HOBT). The reaction temperature was maintained below room temperature (−15° C. to room temperature) in order to minimize side reactions. Cyclic disulfide formation was carried out under high dilute condition using using various oxidizing agents (e.g. oxygen, iodine, immobilized oxidizing agent like EKATHIOX™ resin, (Ekagen Corp., Menlo Park, Calif., etc.)), in various solvents (e.g. water, alcohol, acetonitrile, tetrahydrofuran (THF), acetic acid, chloroform, etc.). See, e.g., B. Kamber, et al., Helv. Chim. Acta, 63(96):899 (1980). Compounds where R 8 , together with R 9 , forms CH 2 CH 2 can be made according to the methods of Williams, et al., J..Med. Chem. 39(7):1346 (1996), e.g., by starting with protected cysteine. [72] 72. 2-Alkylpiperazines were synthesized similarly according to the procedure described in Org. Prep. Proc. Int. 1990, 22, 761-768. Replacement of hydroxyl group by protected sulfur were carried out by Mitsunobu reactions. (Synthesis 1981, 1; Tet. Lett. 1981, 3119 etc.) The protected cysteinal was prepared according to the procedure put forth by O. P. Goel, et al., (Org. Syn. 1988, 67, 69-75). The reductive alkylation can be accomplished with various agents, e.g. sodium triacetoxyborohydride, (Na(OAc) 3 BH), sodium cyanoborohydride or pyridine-borane complex, in solvents such as dichloromethane, dichloroethane, methanol or dimethylformamide, etc. [73] 73. The intermediate and final products were isolated and purified by standard methods, e.g., column chromatography or HPLC. EXAMPLE 1 Synthesis of N-[2-(R)-amino-3-mercaptopropyl]-L-penicillaminyl-1,2,3,4-tetrahydro-3(s)-isoquinoline carbonyl methionine methylester cyclic disulfide (Compound 1) [74] 74. a) N-t-Butoxycarbonyl-S-trityl-L-cysteinyl-N,O-dimethylamide [75] 75. To an ice-cooled solution of N-t-butoxycarbonyl-L-cysteine (8.0 g) and N,O-dimethylhydroxylamine hydrochloride (7.1 g) in 80 ml dimethylformide was added 4.2 ml diethylcyanophosphonate and 14.7 ml diisopropylethylamine, and after stirring at 0° C. for about 1 hour, the reaction mixture was allowed to room temperature overnight. Volatile substances were removed in vacuo to dryness, and the residue was partitioned between ethylacetate and water. Ethylacetate layer was washed with aqueous NaHCO 3 , water, and dried (MgSO 4 ). Solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (165 g) using CHCl 3 as an eluant. Appropriate fractions were pooled, and solvent was removed in vacua to dryness. White foam 8.08 g TLC (silica gel: CHCl 3 /acetone=9:1 R f =0.58). [76] 76. b) 2(R)-t-Butoxycarbonylamino-3-triphenylmethylmercaptopropanal [77] 77. To an ice-cooled solution of N-t-Butoxycarbonyl s-trityl-L-cysteinyl-N,O-dimethylamide (0.85 g) in 20 ml tetrahydrofuran (THF) was added dropwise 3 ml 1.0 M LiAH 4 in THF under nitrogen atmosphere. After the mixture was stirred for about 30 minutes at 0° C., 1M KHSO 4 was slowly added, and the resulting emulsion was filtered through diatomaceous earth pad and further washed with ethylacetate. After drying over anhydrous MgSO 4 , the solvent was removed in vacua to dryness resulting in 0.7 g of the above-titled compound TLC (silica gel; CHCl 3 /acetone=4:1; R f =0.88). [78] 78. c) N-t-Butoxycarbonyl-S-acetamidomethylpenicillaminyl-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl-methionine methylester [79] 79. To an ice-cooled solution of N-t-butoxycarbonyl-L-1,2,3,4-tetrahydro-3(S)-isoquinoline (2.77 g) and L-methionine methylester hydrochloride (2.0 g), 1-hydroxybenzotriazole (HOBT) (1.37 g) and O-Benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU) (3.87 g) in 30 ml dimethylformide was added 4.9 ml diisopropylethylamine (DIEA). After stirring at 0° C. for about 30 minutes, the reaction mixture was allowed to room temperature overnight. Volatile substances were evaporated in vacuo to dryness, and the residue was partitioned between EtOAc and water. EtOAc layer was washed with aqueous NaHCO 3 , water, and dried (MgSO 4 ). Solvent was evaporated in vacuo to dryness. It was treated with 50% trifluoracetic acid in chloroform (40 ml) containing 4.8 ml triethylsilane for about 1 hour, and volatile substances were removed in vacuo to dryness. Trace of trifluoroacetic acid (TFA) was further evaporated with toluene. To the above L-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methylester TFA salt (2.2 g) in dichloromethane (20 ml) cooled to 0° C. was added 1.2 ml DIEA followed by a solution of HOBT (0.7 g), N-t-butoxycarbonyl-S-acetamidomethyl penicillin (1.6 g) in DMF (3 ml), and EDC (1.2 g). The mixture was stirred at 0° C. for about 30 minutes and then allowed to room temperature overnight. Volatile substances were removed in vacuo to dryness. The residue was partitioned between EtOAc and water. Ethylacetate layer was washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ). Solvent was evaporated in vacuo to dryness to yield 3.3 g orange solid. [80] 80. d) L-[S-acetamidomethylpenicillaminyl-1,2,3,4-tetrahydro-3[S]-isoquinolinecarbonyl methionine methylester and its TFA salt [81] 81. N-t-Butoxycarbonyl-S-acetamidomethyl-penicillaminyl-1,2,3,4-tetrahydro-3[S]-isoquinolinecarbonyl methionine methylester (3.3 g) was treated with 50% TFA in CH 2 Cl 2 (20 ml) containing 1 ml triethylsilane for about 30 minutes Volatile substances were removed in vacuo to dryness. Trace of TFA was removed by co-evaporation with toluene several times. The TFA salt was dissolved in CHCl 3 (30 ml), treated with excess triethylamine, washed with water, dried (MgSO 4 ), and solvent was evaporated in vacuo to give free base. [82] 82. e) N-[2(R)-(t-Butoxycarbonyl)amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methyl ester [83] 83. To a solution of 2(R)-t-butoxycarbonylamino-3-triphenyl methyl-mercapto-propanal (0.7 g) and L-[S-acetamido methylpenicillaminyl-1,2,3,4-tetrahydro-3(s)-isoquinolinecarbonyl methionine methylester (0.43 g) in CH 2 Cl 2 (20 ml) containing 1% acetic acid was added triacetoxysodiumborohydride Na(OAc) 3 BH (360 mg) in one portion. After stirring for about 2 hours, the mixture was washed with water, 5% aqueous NaHCO 3 , water, and then dried (MgSO 4 ). The solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (50 g) using CHCl 3 /acetone (19:1 to 9:1) as eluants. Appropriate fractions were pooled and solvents were removed in vacuo to dryness resulting in a white foam (390 mg) of the above title compound. TLC (silica gel; CHCl 3 /acetone=4:1; R f =0.4). [84] 84. f) N-[2(R)-(t-Butoxycarbonyl)amino-3-mercaptopropyl]-L-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide [85] 85. To a solution of N-[2(R)-(t-butoxycarbonyl)amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester (500 mg) in 50 ml 90% aqueous MeOH was added dropwise a solution of iodine (250 mg) in methanol (MeOH) (10 ml). After stirring for about 1 hour, most of methanol was removed in vacuo to a small volume, diluted with water, and extracted with ethylacetate. The ethylacetate extract was washed with water, aqueous Na 2 S 2 O 3 , water, and then dried (MgSO 4 ). The solvent was evaporated in vacuo to dryness resulting in 400 mg of the above title compound. [86] 86. g) N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide [87] 87. Crude N-[2(R)-(t-butoxycarbonyl)amino-3-mercaptopropyl]-L-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide (400 mg) was treated with 90% trifluoroacetic acid (TFA) in water TFA/H 2 O (9:1) (10 ml) for about 30 minutes Volatile substances were removed in vacuo to dryness, and a trace of TFA was evaporated with toluene several times and triturated with hexane, decanted, and then dried. Crude product was subjected to preparative high performance liquid chromatography (HPLC) using C 18 column and 0.1% TFA and CH 3 CN as mobile phase. Appropriate fractions were pooled, and solvents were removed giving the above title compound as a white solid (78 mg). M/e= 541.1. EXAMPLE 2 Synthesis of N-[2-(R)-Amino-3-mercaptopropyl]-L-[s-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine (Compound 4) [88] 88. To a solution of N-[2(R)-(t-butoxycarbonyl)-amino-3-triphenylmethylmercaptopropyl]-L-[s-acetamidomethyl penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methylester (Example I e))(500 mg) in 10 MeOH (50 ml) was added 2 ml 2 N—NaOH. After 30 minutes, most of MeOH was removed in vacuo to a small volume, diluted with water, acidified with 5% aqueous citric acid, and extracted with ethylacetate. The ethylacetate extract was then dried (MgSO 4 ). Solvent was evaporated in vacuo to dryness. The residue was treated with 50% TFA in CH 2 Cl 2 containing triethylsilane (Et 3 SiH) (0.5 ml) for about 40 minutes Volatile substances were removed in dryness, and a trace of TFA was evaporated with toluene and then dried. Crude product was purified by preparative HPLC giving the above titled compound (100 mg) as a white solid. M/e=600.2. EXAMPLE 3 Synthesis of N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl]-2,3-dimethylanilide cyclic disulfide (Compound 9) [89] 89. a) [N-t-Butoxycarbonyl-S-acetamidomethyl]penicillaminyl-2,3-dimethylanilide [90] 90. To an ice-cooled solution of N-[t-butoxycarbonyl)-S-acetamidomethyl penicillamine (Bachem California, Torrance, Calif.) (0.64 g), 2,3-dimethylaniline (0.25 g), hydroxybenzotriazole (0.41 g) in dimethylformide (DMF)/CH 2 Cl 2 (1:1, 20 ml) was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (0.57 g). The mixture was stirred at 0-5° C. for about 30 minutes and then the temperature was slowly allowed to room temperature overnight. After evaporation of the solvents, the residue was partitioned between ethyl acetate (EtOAc) and water. EtOAc extract was washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ). The solvent was evaporated in vacuo to dryness. The residue was chromatographed on silica gel (40 g) using CHCl 3 /acetone= 19:1 as eluants, appropriate fractions were pooled, and solvents were removed in vacuo to dryness giving 350 mg of the above titled compound. TLC (silica gel: CHCl 3 /acetone=4:1, R f −0.77). [91] 91. b) L-[S-acetamidomethylpenicillaminyl-2,3-dimethyl anilide TFA salt [92] 92. [N-t-butoxycarbonyl-S-acetamidomethyl]-penicillaminyl-2,3-dimethylanilide was treated with 50% TFA in CH 2 Cl 2 (20 ml) for about 30 minutes Volatile substances were removed in vacuo to dryness. Trace of TFA was removed by co-evaporation with toluene several times. The TFA salt was dissolved in CHCl 3 (30 ml), treated with excess triethylamine, washed with water, dried (MgSO 4 ), and solvent was evaporated in vacuo to give free base. [93] 93. c) N-[2(R)-(t-Butoxycarbonyl)amino-3-triphenylmethylmercapto propyl]-L-[S-acetamidomethylpenicillaminyl-2,3-dimethylamilide [94] 94. To a stirred solution of 2(R)-t-butoxycarbonylamino-3-triphenylmethylmercaptopropanal (0.5 g; Example 1b) and L-[S-acetamidomethylpenicillaminyl-2,3-dimethylanilide TFA salt (0.3 g) in MeOH containing 1% acetic acid (HOAc) (10 ml) was added portionwise NaCNBH 3 (100 mg). The mixture was stirred at room temperature overnight. Most of the solvent was evaporated in vacuo to a small volume, which was partitioned between EtOAc and water. EtOAc layer was further washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ). After evaporation of solvent, the residue was chromatographed on silica gel (30 g) using CHCl 3 -acetone (19:1 to 9:1) as eluants. Appropriate fractions were pooled, and solvents were evaporated in vacuo to dryness giving 360 mg of the above titled compound. TLC (silica gel: CHCl 3 /acetone=9:1, R f =0.13. [95] 95. d) N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl]-2,3-dimethylanilide cyclic disulfide [96] 96. To a stirred solution of N-[2(R)-(t-butoxycarbonyl) amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl penicillaminyl]-2,3-dimethylamilide (350 mg) in 50 ml 90% MeOH in water was added a solution of iodine (250 mg) in MeOH (5 ml). After 1 hour, most of the solvent was evaporated in vacuo to a small volume, diluted with water, extracted with EtOAc. EtoAc layer was washed with aqueous Na 2 S 2 O 3 , water, then dried (MgSO 4 ). Solvent was removed in vacuo to dryness (220 mg), treated with 90% aqueous TFA (ml) for about 30 minutes, and volatile substances were removed in vacuo to dryness. Crude product was purified by preparative HPLC giving 62 mg of the above titled compound as a white solid. M/e=340.2. EXAMPLE 4 Synthesis of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide, (Compound 28), 1-[2(R) -Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine, (Compound 30), and Bis-1,1′-2,2′-[2(R)-amino-3-mercaptopropyl]-2(S)-[2-mercaptoethyl)-4-(1-naphthoyl)-piperazinetetrasulfide, (Compound 29) [97] 97. a) Synthesis of 1-Benzyl-3(S)-benzyloxycarbonylmethyl piperazine-2,5-dione [98] 98. To an ice-cooled solution of BOC-aspartic acid β-benzyl ester (10 g), hydroxybenzotriazole (HOBT, 4.2 g), and N-benzylglycine ethyl ester (6.4 g) in 80 ml CH 2 Cl 2 was added a cold solution of dicyclohexylcarbodiimide (DCC, 7.1 g) in 20 ml CH 2 Cl 2 . The reaction was stirred for about 1 hour at 0-5° C., then overnight at room temperature. The precipitate was filtered off and the filtrate was evaporated in vacuo to dryness. The residue was partitioned between ethyl acetate and water. The organic layer was washed with 100 ml aqueous NaHCO 3 , water, then dried (MSO 4 ) . Solvent was removed in vacuo to dryness to give 16 g. TLC (silica gel: CHCl 3 /acetone= 9:1, R f =0.55). [99] 99. This was treated with 50% trifluoroacetic acid in CHCl 3 (40 ml) for about 1 hour and the volatile substances were removed in vacuo to dryness. The residue was partitioned between ethyl acetate and saturated aqueous NaHCO 3 . The organic layer was then dried (MgSO 4 ) and the solvent was evaporated in vacuo to give 10 g. TLC (silica gel, CHCl 3 /acetone=9:1, R f =0.14). [100] 100. b) Synthesis of 4-Benzyl-1-tert-butoxycarbonyl-2(S) -(2-hydroxyethyl) piperazine [101] 101. To an ice-cooled solution of the product from Step A (9.73 g) in 200 ml tetrahydrofuran (THF) was added portion wise a 50% mineral dispersion of lithium aluminum hydride (12.5 g) under a nitrogen atmosphere. The reaction mixture was refluxed overnight. After cooling in an ice bath, saturated aqueous Na 2 SO 4 was added dropwise to decompose excess LAH and the white slurry in THF was filtered through a diatomaceous earth pad. The filtrate was concentrated in vacuo to dryness and the residue was dissolved in dichloromethane (55 mg), treated with di-tert-butyl dicarbonate (5.9 g), and stirred for about 1 hour. Aqueous saturated NaHCO 3 (25 ml) was added and stirred for about 2 hours. The organic layer was washed with saturated sodium chloride and dried (MgSO 4 ). After evaporation of solvent, the residue was chromatographed on silica gel (160 g) using CHCl 3 /MeOH (19:1) as eluent. Appropriate fractions were pooled, and solvents were removed in vacuo to dryness, to give 8.7 g of a glass. TLC (silica gel: CHCl 3 /MeOH=9:1, R f =0.56). [102] 102. c) Synthesis of 1-tert-Butoxycarbonyl-2-(S)-(2-hydroxyethyl) piperazine [103] 103. The product from Step B (8.7 g) was dissolved in ethanol (35 ml) treated with Pd(OH) 2 -charcoal (0.8 g) and acetic acid (3 ml). Hydrogenation was carried out under 30 p.s.i. overnight. The reaction mixture was filtered through a diatomaceous earth pad and the solvent was removed in vacuo to dryness. [104] 104. d) Synthesis of 1-tert-Butoxycarbonyl-2(S)-(2-hydroxyethyl)-4-(1-naphthoyl) piperazine [105] 105. To a solution of the product from Step C (8.4 g) in acetonitrile (40 ml) was added 110 ml 1 N aqueous NaOH followed by a solution of 1-naphthoyl chloride (5.14 g) in acetonitrile (20 ml). After about 3 hours stirring, most of the acetonitrile was removed in vacuo and the remaining mixture was extracted with chloroform. It was dried (MgSO 4 ) and the solvent was removed in vacuo to dryness, to give 8.12 g. of product. TLC (silica gel: CHCl 3 /MeOH=9:1, R f = 0.64). [106] 106. e) Synthesis of 1-tert-Butoxycarbonyl-2(S)-(2-triphenylmethylthioethyl)-4-(1-naphthoyl)-piperazine [107] 107. To an ice-cooled solution of triphenylphosphine (0.53 g) in 5 ml dry THF was added dropwise a solution of diethylazodicarboxylate (DEAD, 0.25 g) in 2 ml THF. After stirring at 0-50° C. for about 30 minutes, a solution of the product from Step D (0.4 g) and triphenylmercaptan (0.55 g) in 10 ml THF was added dropwise. The mixture was stirred at 0-5° C. for about 1 hour and room temperature for about 1 hour. The solvent was evaporated in vacuo to dryness and the residue was chromatographed on silica gel (40 g) using CHCl 3 as eluent. Appropriate fractions were pooled and the solvent was removed in vacuo to dryness, to give a pale yellow foam 420 mg. Mass Spec (Electrospray) 665.2 (643+23(sodium)). TLC (silica gel: CHCl 3 /acetone=9:1 R f =0.53). [108] 108. f) Synthesis of 2(S)-(2-Triphenylmethylthioethyl)-4-(1-naphthoyl) piperazine [109] 109. To a stirred solution of the product from Step E (2.2 g) in 30 ml CH 2 Cl 2 was added 10 ml trifluoroacetic acid (TFA). The mixture was stirred for about 30 minutes. Volatile substances were removed in vacuo to dryness. The residue was dissolved in CHCl 3 (50 ml) and treated with excess triethylamine (4 ml). The mixture was washed with water, then dried (MgSO 4 ) and volatile substances were removed in vacuo to dryness, to give a pale yellow glass, 2.1 g; TLC (silica gel; CHCl 3 /MeOH=9:1, R f =0.63). [110] 110. g) Synthesis of 1-[2(R)-N-tert-Butoxycarbonylamino-3-triphenyl methylthiopropyl]-2(S)-(2-triphenylmethylthioethyl)-4-(1-naphthoyl)-piperazine [111] 111. To a solution of the product from Step F (0.9 g) and 2(R)-N-tert-butoxycarbonylamino-3-triphenylmethylthiopropanal (1.2 g) prepared according to the procedure of O. P. Goel, et al., (Org. Syn. 1988, 67, 69-75), in CH 2 Cl 2 (20 ml) containing 1% acetic acid, was added 4 g of molecular sieves 4 Å followed by portion wise addition of Na(OAc) 3 BH (1 g) over a 30 minutes period. After stirring for about 2 hours, the mixture was filtered and the filtrate was washed with water, 5% aqueous NaHCO 3 , water, and then dried (MgSO 4 ). The solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (60 g) using CHCl 3 as an eluent. Appropriate fractions were pooled and solvent was removed in vacuo to dryness, to give 0.6 g white foam. TLC (silica gel, CHCl 3 /acetone=9:1; R f =0.55); Mass Spec (Electro Spray) 974.3. [112] 112. h) Synthesis of 1-[2(R)-amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide, (Compound 28), and Bis-1,1′-2,2′-[2(R)-Amino-3-mercaptopropyl]-2(S)-[2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-tetrasulfide, (Compound 29) [113] 113. To a stirred solution of the product from step g (0.7 g) in CHCl 3 /CH 3 OH (1:3, 60 ml) was added a solution of iodine in methanol (0.2 g in 5 ml). After stirring for about 40 minutes most of the solvents were removed in vacuo to dryness and the residue was partitioned between ethyl acetate (30 ml) and 5% aqueous Na 2 S 2 O 3 . The organic layer was washed with water, then dried (MgSO 4 ). After evaporation of solvent the residue was treated with 50% trifluoroacetic acid in dichloromethane (10 ml) for about 30 minutes. Volatile substances were removed in vacuo to dryness and the residue was triturated with ether and filtered. [114] 114. The crude product was subjected to preparative high performance liquid chromatography (HPLC) using a C 18 column and 0.1% aqueous TFA and CH 3 CN as the mobile phase. Earlier fractions (retention=5 minutes, CH 3 CN/0.1% aqueous TFA= 50:50, elution rate=1 ml/min) gave the white solid 1,2 cyclodisulfide; Mass. Spec. (Electrospray)=388.1. Later fractions (retention time=7.2 minutes using the same isocratic conditions) gave the dimer; Mass Spec. (Electrospray)=775.1 The ratio of cyclic disulfide and dimeric tetrasulfide was about 4 to 1. EXAMPLE 5 Alternative cyclization of compound 30 using immobilized oxidizing resin (EKATHIOX™ resin) or air. [115] 115. a) Synthesis of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) [116] 116. The product from Step G (450 mg) was treated for about 30 minutes with 50% TFA in CH 2 Cl 2 (10 ml) containing 1 ml triethylsilane. Volatile substances were then removed in vacuo to dryness. The residue was triturated with ether, filtered, then dried, resulting in 280 mg of 1-(2(R)-amino-3-mercaptopropyl]-2(S)-(2-mercaptoethyl)-4-(1-naphthoyl)-piperazine, (Compound 30). Mass spec (electrospray) 390.3 [117] 117. b) Cyclization of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) to form 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide (Compound 28) [118] 118. 100 mg of the product from Step a) was dissolved in 10 ml aqueous CH 3 CN (H 2 O/CH 3 CN=7.3), and treated with 3 g of EKATHIOX™ resin (0.34 mmoles/gm). The mixture was stirred at room temperature for about 6 hours. The mixture was then filtered, the resin washed with aqueous methanol (1:3), and most of the organic solvent was removed in vacuo to a small volume. The concentrate was subjected to preparative HPLC using 0.1% aqueous TFA and CH 3 CN as mobile phase. Appropriate fractions were pooled and most of the solvents removed in vacuo to small volume. The concentrate was then lyophilized. [119] 119. Alternatively, the solution of 1-[2(R)-amino-3-mercaptopropyl]-2(S)-(2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) in aqueous CH 3 CN was stirred with air in pH 6-8 range. In both instances the reaction mixture showed a distribution of the cyclic disulfide and the tetrasulfide dimer in the ratio of about 4 to 1. OTHER EMBODIMENTS [120] 120. It is to be understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the claims.
A family of compounds capable of inhibiting the activity of prenyl transferases. The compounds are covered by the four following formulas Each of the R groups is defined in the disclosure.
Briefly outline the background technology and the problem the invention aims to solve.
[ "CROSS-REFERENCE TO RELATED APPLICATION [1] 1.", "This application is a continuation-in-part of U.S. patent application 08/675,439, filed Jun. 28, 1996.", "BACKGROUND OF THE INVENTION [2] 2.", "The Ras family of proteins are important in the signal transduction pathway modulating cell growth.", "The protein is produced in the ribosome, released into the cytosol, and post-translationally modified.", "The first step in the series of post-translational modifications is the alkylation of Cys 168 with farnesyl or geranylgeranyl pyrophosphate in a reaction catalyzed by prenyl transferase enzymes such as farnesyl transferase and geranylgeranyl transferase (Hancock, J F, et al.", ", Cell 57:1167-1177 (1989)).", "Subsequently, the three C-terminal amino acids are cleaved (Gutierrez, L., et al.", ", EMBO J. 8:1093-1098 (1989)), and the terminal Cys is converted to a methyl ester (Clark, S., et al.", ", Proc.", "Nat'l Acad.", "Sci.", "(USA) 85:4643-4647 (1988)).", "Some forms of Ras are also reversibly palmitoylated on cysteine residues immediately N-terminal to Cys 168 (Buss, J E, et al.", ", Mol.", "Cell.", "Biol.", "6:116-122 (1986)).", "It is believed that these modifications increase the hydrophobicity of the C-terminal region of Ras, causing it to localize at the surface of the cell membrane.", "Localization of Ras to the cell membrane is necessary for signal transduction (Willumsen, B M, et al.", ", Science 310:583-586 (1984)).", "[3] 3.", "Oncogenic forms of Ras are observed in a relatively large number of cancers including over 50 percent of colon cancers and over 90 percent of pancreatic cancers (Bos, J L, Cancer Research 49:4682-4689 (1989)).", "These observations suggest that intervention in the function of Ras mediated signal transduction may be useful in the treatment of cancer.", "[4] 4.", "Previously, it has been shown that the C-terminal tetrapeptide of Ras has the “CAAX”", "motif (wherein C is cysteine, A is an aliphatic amino acid, and X is any amino acid).", "Tetrapeptides having this structure have been shown to be inhibitors of prenyl transferases (Reiss, et al.", ", Cell 62:81-88 (1990)).", "Poor potency of these early farnesyl transferase inhibitors has prompted the search for new inhibitors with more favorable pharmacokinetic behavior (James, G L, et al.", ", Science 260:1937-1942 (1993);", "Kohl, N E, et al.", ", Proc.", "Nat'l Acad.", "Sci.", "USA 91:9141-9145 (1994);", "deSolms, S J, et al.", ", J. Med.", "Chem.", "38:3967-3971 (1995);", "Nagasu, T, et al.", ", Cancer Research 55:5310-5314 (1995);", "Lerner, E C, et al.", ", J. Biol.", "Chem.", "270:26802-26806 (1995);", "Lerner, E C, et al.", ", J. Biol.", "Chem.", "270:26770 (1995);", "and James, et al.", ", Proc.", "Natl.", "Acad.", "Sci.", "USA 93:4454 (1996)).", "[5] 5.", "Recently, it has been shown that a prenyl transferase inhibitor can block growth of Ras-dependent tumors in nude mice (Kohl, N E, et al.", ", Proc.", "Nat'l Acad.", "Sci.", "USA 91:9141-9145 (1994)).", "In addition, it has been shown that over 70 percent of a large sampling of tumor cell lines are inhibited by prenyl transferase inhibitors with selectivity over non-transformed epithelial cells (Sepp-Lorenzino, I, et al.", ", Cancer Research, 55:5302-5309 (1995)).", "Inhibiting farnesylation has been disclosed as a method of treating hepatitis delta virus infection, (Casey, P, et al.", ", WO 97/31641).", "SUMMARY OF THE INVENTION [6] 6.", "In one aspect, the invention features a compound of formula I or formula II [7] 7.", "wherein [8] 8.", "R 1 is N(R 10 ) (R 11 );", "[9] 9.", "R 2 is thio lower alkyl;", "[10] 10.", "each of R 3 and R 5 , independently, is CH 2 or C(O);", "[11] 11.", "R 4 is substituted or unsubstituted thio lower alkyl, [12] 12.", "wherein said substituent is CH 2 NHC(O)R 13 and said substituent is attached to said thio group;", "[13] 13.", "R 6 is a residue of a natural or synthetic α-amino acid;", "[14] 14.", "R 7 is a residue of a natural or synthetic α-amino acid;", "[15] 15.", "R 8 is OH or lower alkoxy, or, together with R 7 , forms homoserinelactone;", "[16] 16.", "each of R 9 , R 10 and R 11 , independently, is H or lower alkyl;", "[17] 17.", "R 12 is substituted or unsubstituted cycloalkyl, cycloalkyl lower alkyl, aryl, aryl lower alkyl, heterocycle, or heterocycle lower alkyl, wherein said substituent is lower alkyl, aryl, halo, lower alkoxy, or C(O)—R 7 —R 8 ;", "[18] 18.", "R 13 is lower alkyl, aryl, or aryl lower alkyl;", "[19] 19.", "R 18 is H or, together with R 9 , forms CH 2 CH 2 ;", "[20] 20.", "provided if R 4 is unsubstituted thio lower alkyl, the free thio group of R 2 and the free thio group of R 4 may form a disulfide bond;", "[21] 21.", "or a pharmaceutically acceptable salt thereof.", "[22] 22.", "In another aspect, the present invention is directed to a process for preparing a compound of Formula I or Formula II.", "[23] 23.", "In one embodiment, the compound is of formula I where R 6 is —N(R 14 )CH(R 15 )C(O)—, where R 14 is H or lower alkyl, and R 15 is substituted or unsubstituted lower alkyl, aryl, aryl lower alkyl, heterocycle, or heterocycle lower alkyl where said substituent is lower alkyl, halo, or lower alkoxy, or where R 15 , together with NR 14 C attached thereto, form heterocycle;", "and R 7 is —N(R 16 )CH(R 17 )C(O)— where R 16 is H or lower alkyl, and R 17 is (CH 2 ) m S(O) n CH 3 or substituted or unsubstituted lower alkyl, thio lower alkyl, where said substituent is C(O)N(R 10 )(R 11 ), m is 1-6, n is 0-2, and R 8 is OH or lower alkoxy.", "In this embodiment, R 2 can be CH 2 SH;", "R 4 can be C(CH 3 ) 2 SH or CH 2 SH wherein the free thio group of R 2 and the free thio group of R 4 form a disulfide bond;", "R 15 , together with NR 14 C attached thereto, can form heterocycle;", "R 16 can be H;", "and R 17 can be (CH 2 ) 2 S(O) n CH 3 ;", "furthermore, R 1 can be NH 2 ;", "R 3 can be CH 2 ;", "R 5 can be CO;", "and R 8 can be OH or OCH 3 .", "In the same embodiment, R 2 can be (CH 2 )SH;", "R 4 can be C(CH 2 ) 2 SCH 2 NHCOCH 3 or CH 2 SCH 2 NHCOCH 3 ;", "R 15 , together with NR 14 C attached thereto, can form heterocycle;", "R 16 can be H, and R 17 can be (CH 2 ) 2 S(O) n CH 3 ;", "furthermore, R 1 is NH 2 ;", "R 3 is CH 2 ;", "R 5 is C(O);", "and R 8 is OH or OCH 3 .", "[24] 24.", "In another embodiment, the compound is of formula II, wherein R 2 is CH 2 SH;", "R 4 is C(CH 3 ) 2 SH or CH 2 SH wherein the free thio group of R 2 and the free thio group of R 4 form a disulfide bond;", "R 12 is substituted or unsubstituted aryl or is aryl lower alkyl, and R 18 is H. In this embodiment, R 1 can be NH 2 ;", "R 3 can be CH 2 ;", "R 5 can be C(O);", "R 9 can be H;", "and R 12 can be substituted or unsubstituted phenyl or benzyl, wherein said substituent is lower alkyl or halo.", "[25] 25.", "In a still further embodiment, R 2 is (CH 2 )SH;", "R 4 is C(CH 2 ) 2 SCH 2 NHCOCH 3 or CH 2 SCH 2 NHCOCH 3 ;", "and R 12 is subsitituted or unsubstituted aryl or aryl lower alkyl.", "In this embodiment, R 1 can be NH 2 ;", "R 3 can be CH 2 ;", "R 5 can be CO;", "R 9 can be H;", "and R 12 can be substituted or unsubstituted phenyl or benzyl, wherein said substituent is lower alkyl or halo.", "[26] 26.", "Examples of the present invention include the following: [27] 27.", "In another aspect, the invention features a compound of formula III or formula IV [28] 28.", "where [29] 29.", "Y is CH 2 or C(O);", "[30] 30.", "R 1 , R 2 , R 3 , and R 4 , each is, independently, H, lower alkyl, optionally substituted arylalkyl, optionally substituted alkenyl, (C 1 -C 18 )-aliphatic acyl, or arylacyl;", "[31] 31.", "R 5 and R 6 each is, independently, H or CH 3 ;", "[32] 32.", "R 9 and R 10 each is independently selected from the group consisting of H, lower alkyl, and C 3 -C 6 cycloalkyl;", "[33] 33.", "Ar is optionally substituted aryl or optionally substituted heterocycle;", "[34] 34.", "n is 0 or an integer from 1 to 4;", "[35] 35.", "wherein each substituent is, independently, aryl, heterocycle, halogen, OR 9 , NR 9 R 10 , CN, NO 2 , CF 3 , or lower alkyl, said lower alkyl optionally substituted with C 1 -C 4 alkoxy, NR 9 R 10 , C 3 -C 6 cycloalkyl, or OH;", "[36] 36.", "or a pharmaceutically acceptable salt thereof.", "[37] 37.", "In still another aspect, the present invention is directed to a process for preparing a compound of Formula III or Formula IV.", "[38] 38.", "A preferred group of compounds of Formula III or Formula IV include the following: [39] 39.", "In yet another aspect, the invention features a compound of formula V: [40] 40.", "wherein [41] 41.", "Ar is optionally substituted aryl or optionally substituted heterocycle, wherein each substituent is independently selected from the group consisting of aryl, heterocycle, halogen, OR 9 , NR 9 R 10 , CN, NO 2 , CF 3 , and lower alkyl, said lower alkyl optionally substituted with (C 1 -C 4 )-alkoxy, NR 9 R 10 , C 3 -C 6 cycloalkyl, or OH;", "[42] 42.", "R 1 and R 2 each is, independently, CH 2 or C(O);", "[43] 43.", "R 3 and R 4 each is, independently, H or CH 3 ;", "[44] 44.", "R 5 , R 6 , R 7 , and R 8 each is independently selected from the group consisting of H, or an optionally substituted moiety selected from the group consisting of (C 1 -C 8 )-alkyl, alkenyl, alkynyl, aryl, and heterocycle;", "[45] 45.", "wherein said optionally substituted moiety is optionally substituted by one or more substituents independently selected from the group consisting of (C 3 -C 6 ) -cycloalkyl, optionally further substituted aryl, and optionally further substituted heterocycle, [46] 46.", "wherein said optionally further substituted aryl and heterocycle are optionally substituted by one or more substituents independently selected from the group consisting of (C 1 -C 4 )-alkyl, halogen, (CH 2 ) m OR 9 , and (CH 2 ) m NR R 10 ;", "[47] 47.", "R 9 and R 10 each is, independently, H lower alkyl or (C 3 -C 6 ) cycloalkyl;", "[48] 48.", "R 11 is H or NH 2 ;", "[49] 49.", "m is 0 or an integer from 1 to 4;", "[50] 50.", "n is 0, 1, or 2;", "[51] 51.", "or a pharmaceutically acceptable salt thereof.", "[52] 52.", "In another aspect, the present invention is directed to a process for preparing a compound of Formula V. [53] 53.", "A preferred group of compounds of Formula V includes the following: [54] 54.", "The compounds of the present invention may have asymmetric centers and occur as racemates, racemic mixtures, and as individual diastereomers, with all possible isomers, including optical isomers, being included in the present invention.", "For simplicity, where no specific configuration is depicted in a structural formula, it is understood that all enantiomeric forms and mixtures thereof are represented.", "[55] 55.", "As used herein, “lower alkyl”", "is intended to include saturated aliphatic hydrocarbon groups having 1-6 carbon atoms.", "Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, and the like.", "The term “alkyl”", "refers to saturated aliphatic hydrocarbon groups having up to 18 carbon atoms.", "The terms “alkenyl”", "and “alkynyl”", "refer to unsaturated aliphatic hydrocarbon groups having 2-18 carbon atoms and from 1 to 5 double or triple bonds.", "“Lower alkoxy”", "groups include those groups having 1-6 carbons.", "Examples of lower alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, and the like.", "All alkyl, alkenyl, alkynyl and alkoxy groups may be branched or straight chained, but are noncyclic.", "The term “cycloalkyl”", "means a 3-7 carbon ring.", "Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloseptyl.", "The term “halo”", "means chloro, bromo, iodo, or fluoro.", "The terms “heterocycle lower alkyl,” “thio lower alkyl,” “cycloalkyl lower alkyl”, and “lower alkyl,” are substituted, respectively, with one to three heterocycle, thio, cycloalkyl, and aryl groups.", "[56] 56.", "As used herein, “aryl”", "is intended to include any stable monocyclic, bicyclic, or tricyclic carbon ring(s) of up to 7 members in each ring, wherein at least one ring is aromatic.", "Examples of aryl groups include phenyl, naphthyl, anthracenyl, biphenyl, tetrahydronaphthyl, indanyl, phenanthrenyl, and the like.", "[57] 57.", "The term heterocycle, as used herein, represents a stable 5- to 7-membered monocyclic or stable 8- to 11-membered bicyclic or stable 11 to 15-membered tricyclic heterocyclic ring which is either saturated or unsaturated, and which consists of carbon atoms and from one to four heteroatoms selected from the group consisting of N, O, and S, and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring.", "The heterocyclic ring may be attached at any heteroatom or carbon atom which results in the creation of a stable structure.", "Examples of such heterocyclic elements include, but are not limited to, azepinyl, benzimidazolyl, benzisoxazolyl, benzofurazanyl, benzopyranyl, benzothiopyranyl, benzofuryl, benzothiazolyl, benzothienyl, benzoxazolyl, chromanyl, cinnolinyl, dihydrobenzofuryl, dihydrobenzothienyl, dihydrobenzothiopyranyl, dihydrobenzothio-pyranyl sulfone, furyl, imidazolidinyl, imidazolinyl, imidazolyl, indolinyl, indolyl, isochromanyl, isoindolinyl, isoquinolinyl, isothiazolidinyl, isothiazolyl, isothiazolidinyl, morpholinyl, naphthyridinyl, oxadiazolyl, 2-oxoazepinyl, 2-oxopiperazinyl, 2-oxopiperidinyl, 2-oxopyrrolidinyl, piperidyl, piperazinyl, pyridyl, pyridyl N-oxide, quinoxalinyl, tetrahydrofuryl, tetrahydroisoquinolinyl, tetrahydro-quinolinyl, thiamorpholinyl, thiamorpholinyl sulfoxide, thiazolyl, thiazolinyl, thiazolidinyl, thienofuryl, thienothienyl, thienyl, and the like.", "[58] 58.", "When a group is substituted, it may be substituted one to four times.", "The various substituents may be attached to carbon atoms or to heteroatoms (e.g., S, N, or O).", "[59] 59.", "As used herein, the term “residue of an α-amino acid”", "stands for an α-amino acid residue which is either a natural α-amino acid which is found in nature (e.g., cysteinyl, methionyl, phenylalaninyl, leucinyl, etc.) or a synthetic α-amino acid which is not found in nature (e.g., neurleucyl or the residue of 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid or penicillamine, etc.).", "[60] 60.", "The compounds of this invention can be provided in the form of pharmaceutically acceptable salts.", "Acceptable salts include, but are not limited to acid addition salts of inorganic acids such as acetate, maleate, fumarate, tartrate, succinate, citrate, lactate, methanesulfonate, p-toluenesulfonate, pamoate, salicylate, oxalate, and stearate.", "Also within the scope of the present invention, where applicable, are salts formed from bases such as sodium or potassium hydroxide.", "For further examples of pharmaceutically acceptable salts see, “Pharmaceutical Salts,” J. Pharm.", "Sci.", "66:1 (1977).", "[61] 61.", "In another aspect, the invention features a method of inhibiting prenyl transferases (e.g., farnesyl transferase or geranylgeranyl transferase) in a subject, e.g., a mammal such as a human, by administering to the subject a therapeutically effective amount of a compound of formula I, formula II, formula III, formula IV, or formula V. In particular, the present invention also covers a method of treating restenosis or tissue proliferative diseases (i.e., tumor) in a subject by administering to the subject a therapeutically effective amount of a compound or its salt.", "Examples of a tissue proliferative disease include both those associated with benign (e.g., non-malignant) cell proliferation such as fibrosis, benign prostatic hyperplasia, atherosclerosis, and restenosis, and those associated with malignant cell proliferation, such as cancer (e.g., ras-mutant tumors).", "Examples of treatable tumors include breast, colon, pancreas, prostate, lung, ovarian, epidermal, and hematopoietic cancers (Sepp-Lorenzino, I, et al.", ", Cancer Research 55:5302 (1995)).", "[62] 62.", "A therapeutically effective amount of a compound of this invention and a pharmaceutically acceptable carrier substance (e.g., magnesium carbonate, lactose, or a phospholipid with which the therapeutic compound can form a micelle) together form a pharmaceutical composition (e.g., a pill, tablet, capsule, or liquid) for administration (e.g., orally, intravenously, transdermally, or subcutaneously) to a subject in need of the compound.", "The pill, tablet, or capsule can be coated with a substance capable of protecting the composition from the gastric acid or intestinal enzymes in the subject's stomach for a period of time sufficient to allow the composition to pass undigested into the subject's small intestine.", "[63] 63.", "The compounds of the present invention may be administered in a dosage range of about 0.0001 to 200 mg/kg/day, preferably 0.01 to 100 mg/kg/day.", "A dose of a compound of the present invention for treating the above-mentioned diseases or disorders varies depending upon the manner of administration, the age and the body weight of the subject, and the condition of the subject to be treated, and ultimately will be decided by the attending physician or veterinarian.", "Such an amount of the compound as determined by the attending physician or veterinarian is referred to herein as a “therapeutically effective amount.”", "[64] 64.", "Also contemplated within the scope of the invention are a method of preparing the compounds of formula I, formula II, formula III, formula IV, and formula V, and the novel chemical intermediates used in these syntheses as described herein.", "[65] 65.", "Other features and advantages of the present invention will be apparent from the detailed description of the invention and from the claims.", "DETAILED DESCRIPTION OF THE INVENTION [66] 66.", "It is believed that one skilled in the art can, based on the description herein, utilize the present invention to its fullest extent.", "The following specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.", "[67] 67.", "A compound of the present invention can be tested for farnesyl transferase inhibiting activity by testing said compound in a farnesyl transferase in vitro assay, such as the assay described below.", "[68] 68.", "Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.", "Also, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference.", "[69] 69.", "Farnesyl transferase activity is assayed by [ 3 H] farnesylation of recombinant human H-Ras protein wild type, using microplate and filtration method.", "Incubation mixture contains, in a total volume of 25 μl: 50 mM Tris HCl (pH 7.5), 5 mM dithiothreitol, 20 μM ZnCl 2 , 40 mM MgCl 2 , 0.6 μM [ 3 H] farnesyl pyrophosphate (22.3 Ci/mmol), 4 μM H-Ras and 10 μg of farnesyl transferase from human brain cytosol.", "Test compounds are added in adequate solvent and incubations start by addition of farnesyl transferase.", "After approximately 60 minutes at approximately 37° C., the reaction is stopped by addition of 100 μl of 10% HCl in ethanol and allowed to incubate approximately 15 minutes at approximately 37° C., then 150 μl of absolute ethanol are added and incubation mixture is filtered on Unifilter GF/B microplates and washed 6 times with ethanol.", "After addition of 50 μl of Microscint 0, plates were counted on a Packard Top Count scintillation counter.", "Geranylgeranyl transferase activity is assayed by the same method, but using 4 μM human recombinant H-Ras CVLL type, 0.6 μM [ 3 H] geranylgeranyl-pyrophosphate (19.3 Ci/mmmol) and 100 μg of geranylgeranyl transferase from human brain.", "[70] 70.", "The following is a description of the synthesis of compounds 1, 4, 9.", "Compounds 2,3,5-8, 10-20 can be prepared in an analogous manner by a person of ordinary skill in the art using appropriate starting materials.", "Compounds 21, 28, 29, and 30 were prepared using the reactions summarized in reaction scheme I. Compound 22 was prepared using the reactions summarized in reaction schemes II and IV.", "Compounds 25, 26, and 27 were prepared using the reactions summarized in reaction scheme V. Compound 31 may be prepared using the reactions summarized in scheme III.", "Other compounds of the invention can be prepared in an analogous manner by a person of ordinary skill in the art using appropriate starting materials.", "[71] 71.", "The compounds of the invention were prepared using standard solution phase methodologies, e.g., as described in Greenstein, et al.", ", Chemistry of the Amino Acids, Vols.", "1-3 (J.", "Wiley, New York (1961));", "and M. Bodanszky, et al.", ", The Practice of Peptide Synthesis (Springer-Verlag, 1984)).", "The condensation reactions were carried out in an inert organic solvent, e.g., dimethylformide, dichloromethane, tetrahydrofuran, benzene or acetonitrile, using a suitable mild condensing agent, e.g., 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide-HCl (EDC), 0-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU), and optionally a catalyst, e.g., 1-hydroxybenzotriazole (HOBT).", "The reaction temperature was maintained below room temperature (−15° C. to room temperature) in order to minimize side reactions.", "Cyclic disulfide formation was carried out under high dilute condition using using various oxidizing agents (e.g. oxygen, iodine, immobilized oxidizing agent like EKATHIOX™ resin, (Ekagen Corp.", ", Menlo Park, Calif.", ", etc.)), in various solvents (e.g. water, alcohol, acetonitrile, tetrahydrofuran (THF), acetic acid, chloroform, etc.).", "See, e.g., B. Kamber, et al.", ", Helv.", "Chim.", "Acta, 63(96):899 (1980).", "Compounds where R 8 , together with R 9 , forms CH 2 CH 2 can be made according to the methods of Williams, et al.", ", J..", "Med.", "Chem.", "39(7):1346 (1996), e.g., by starting with protected cysteine.", "[72] 72.", "2-Alkylpiperazines were synthesized similarly according to the procedure described in Org.", "Prep.", "Proc.", "Int.", "1990, 22, 761-768.", "Replacement of hydroxyl group by protected sulfur were carried out by Mitsunobu reactions.", "(Synthesis 1981, 1;", "Tet.", "Lett.", "1981, 3119 etc.) The protected cysteinal was prepared according to the procedure put forth by O. P. Goel, et al.", ", (Org.", "Syn.", "1988, 67, 69-75).", "The reductive alkylation can be accomplished with various agents, e.g. sodium triacetoxyborohydride, (Na(OAc) 3 BH), sodium cyanoborohydride or pyridine-borane complex, in solvents such as dichloromethane, dichloroethane, methanol or dimethylformamide, etc.", "[73] 73.", "The intermediate and final products were isolated and purified by standard methods, e.g., column chromatography or HPLC.", "EXAMPLE 1 Synthesis of N-[2-(R)-amino-3-mercaptopropyl]-L-penicillaminyl-1,2,3,4-tetrahydro-3(s)-isoquinoline carbonyl methionine methylester cyclic disulfide (Compound 1) [74] 74.", "a) N-t-Butoxycarbonyl-S-trityl-L-cysteinyl-N,O-dimethylamide [75] 75.", "To an ice-cooled solution of N-t-butoxycarbonyl-L-cysteine (8.0 g) and N,O-dimethylhydroxylamine hydrochloride (7.1 g) in 80 ml dimethylformide was added 4.2 ml diethylcyanophosphonate and 14.7 ml diisopropylethylamine, and after stirring at 0° C. for about 1 hour, the reaction mixture was allowed to room temperature overnight.", "Volatile substances were removed in vacuo to dryness, and the residue was partitioned between ethylacetate and water.", "Ethylacetate layer was washed with aqueous NaHCO 3 , water, and dried (MgSO 4 ).", "Solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (165 g) using CHCl 3 as an eluant.", "Appropriate fractions were pooled, and solvent was removed in vacua to dryness.", "White foam 8.08 g TLC (silica gel: CHCl 3 /acetone=9:1 R f =0.58).", "[76] 76.", "b) 2(R)-t-Butoxycarbonylamino-3-triphenylmethylmercaptopropanal [77] 77.", "To an ice-cooled solution of N-t-Butoxycarbonyl s-trityl-L-cysteinyl-N,O-dimethylamide (0.85 g) in 20 ml tetrahydrofuran (THF) was added dropwise 3 ml 1.0 M LiAH 4 in THF under nitrogen atmosphere.", "After the mixture was stirred for about 30 minutes at 0° C., 1M KHSO 4 was slowly added, and the resulting emulsion was filtered through diatomaceous earth pad and further washed with ethylacetate.", "After drying over anhydrous MgSO 4 , the solvent was removed in vacua to dryness resulting in 0.7 g of the above-titled compound TLC (silica gel;", "CHCl 3 /acetone=4:1;", "R f =0.88).", "[78] 78.", "c) N-t-Butoxycarbonyl-S-acetamidomethylpenicillaminyl-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl-methionine methylester [79] 79.", "To an ice-cooled solution of N-t-butoxycarbonyl-L-1,2,3,4-tetrahydro-3(S)-isoquinoline (2.77 g) and L-methionine methylester hydrochloride (2.0 g), 1-hydroxybenzotriazole (HOBT) (1.37 g) and O-Benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HBTU) (3.87 g) in 30 ml dimethylformide was added 4.9 ml diisopropylethylamine (DIEA).", "After stirring at 0° C. for about 30 minutes, the reaction mixture was allowed to room temperature overnight.", "Volatile substances were evaporated in vacuo to dryness, and the residue was partitioned between EtOAc and water.", "EtOAc layer was washed with aqueous NaHCO 3 , water, and dried (MgSO 4 ).", "Solvent was evaporated in vacuo to dryness.", "It was treated with 50% trifluoracetic acid in chloroform (40 ml) containing 4.8 ml triethylsilane for about 1 hour, and volatile substances were removed in vacuo to dryness.", "Trace of trifluoroacetic acid (TFA) was further evaporated with toluene.", "To the above L-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methylester TFA salt (2.2 g) in dichloromethane (20 ml) cooled to 0° C. was added 1.2 ml DIEA followed by a solution of HOBT (0.7 g), N-t-butoxycarbonyl-S-acetamidomethyl penicillin (1.6 g) in DMF (3 ml), and EDC (1.2 g).", "The mixture was stirred at 0° C. for about 30 minutes and then allowed to room temperature overnight.", "Volatile substances were removed in vacuo to dryness.", "The residue was partitioned between EtOAc and water.", "Ethylacetate layer was washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ).", "Solvent was evaporated in vacuo to dryness to yield 3.3 g orange solid.", "[80] 80.", "d) L-[S-acetamidomethylpenicillaminyl-1,2,3,4-tetrahydro-3[S]-isoquinolinecarbonyl methionine methylester and its TFA salt [81] 81.", "N-t-Butoxycarbonyl-S-acetamidomethyl-penicillaminyl-1,2,3,4-tetrahydro-3[S]-isoquinolinecarbonyl methionine methylester (3.3 g) was treated with 50% TFA in CH 2 Cl 2 (20 ml) containing 1 ml triethylsilane for about 30 minutes Volatile substances were removed in vacuo to dryness.", "Trace of TFA was removed by co-evaporation with toluene several times.", "The TFA salt was dissolved in CHCl 3 (30 ml), treated with excess triethylamine, washed with water, dried (MgSO 4 ), and solvent was evaporated in vacuo to give free base.", "[82] 82.", "e) N-[2(R)-(t-Butoxycarbonyl)amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methyl ester [83] 83.", "To a solution of 2(R)-t-butoxycarbonylamino-3-triphenyl methyl-mercapto-propanal (0.7 g) and L-[S-acetamido methylpenicillaminyl-1,2,3,4-tetrahydro-3(s)-isoquinolinecarbonyl methionine methylester (0.43 g) in CH 2 Cl 2 (20 ml) containing 1% acetic acid was added triacetoxysodiumborohydride Na(OAc) 3 BH (360 mg) in one portion.", "After stirring for about 2 hours, the mixture was washed with water, 5% aqueous NaHCO 3 , water, and then dried (MgSO 4 ).", "The solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (50 g) using CHCl 3 /acetone (19:1 to 9:1) as eluants.", "Appropriate fractions were pooled and solvents were removed in vacuo to dryness resulting in a white foam (390 mg) of the above title compound.", "TLC (silica gel;", "CHCl 3 /acetone=4:1;", "R f =0.4).", "[84] 84.", "f) N-[2(R)-(t-Butoxycarbonyl)amino-3-mercaptopropyl]-L-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide [85] 85.", "To a solution of N-[2(R)-(t-butoxycarbonyl)amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester (500 mg) in 50 ml 90% aqueous MeOH was added dropwise a solution of iodine (250 mg) in methanol (MeOH) (10 ml).", "After stirring for about 1 hour, most of methanol was removed in vacuo to a small volume, diluted with water, and extracted with ethylacetate.", "The ethylacetate extract was washed with water, aqueous Na 2 S 2 O 3 , water, and then dried (MgSO 4 ).", "The solvent was evaporated in vacuo to dryness resulting in 400 mg of the above title compound.", "[86] 86.", "g) N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide [87] 87.", "Crude N-[2(R)-(t-butoxycarbonyl)amino-3-mercaptopropyl]-L-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine methylester cyclic disulfide (400 mg) was treated with 90% trifluoroacetic acid (TFA) in water TFA/H 2 O (9:1) (10 ml) for about 30 minutes Volatile substances were removed in vacuo to dryness, and a trace of TFA was evaporated with toluene several times and triturated with hexane, decanted, and then dried.", "Crude product was subjected to preparative high performance liquid chromatography (HPLC) using C 18 column and 0.1% TFA and CH 3 CN as mobile phase.", "Appropriate fractions were pooled, and solvents were removed giving the above title compound as a white solid (78 mg).", "M/e= 541.1.", "EXAMPLE 2 Synthesis of N-[2-(R)-Amino-3-mercaptopropyl]-L-[s-acetamidomethyl-penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinoline carbonyl methionine (Compound 4) [88] 88.", "To a solution of N-[2(R)-(t-butoxycarbonyl)-amino-3-triphenylmethylmercaptopropyl]-L-[s-acetamidomethyl penicillaminyl]-1,2,3,4-tetrahydro-3(S)-isoquinolinecarbonyl methionine methylester (Example I e))(500 mg) in 10 MeOH (50 ml) was added 2 ml 2 N—NaOH.", "After 30 minutes, most of MeOH was removed in vacuo to a small volume, diluted with water, acidified with 5% aqueous citric acid, and extracted with ethylacetate.", "The ethylacetate extract was then dried (MgSO 4 ).", "Solvent was evaporated in vacuo to dryness.", "The residue was treated with 50% TFA in CH 2 Cl 2 containing triethylsilane (Et 3 SiH) (0.5 ml) for about 40 minutes Volatile substances were removed in dryness, and a trace of TFA was evaporated with toluene and then dried.", "Crude product was purified by preparative HPLC giving the above titled compound (100 mg) as a white solid.", "M/e=600.2.", "EXAMPLE 3 Synthesis of N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl]-2,3-dimethylanilide cyclic disulfide (Compound 9) [89] 89.", "a) [N-t-Butoxycarbonyl-S-acetamidomethyl]penicillaminyl-2,3-dimethylanilide [90] 90.", "To an ice-cooled solution of N-[t-butoxycarbonyl)-S-acetamidomethyl penicillamine (Bachem California, Torrance, Calif.) (0.64 g), 2,3-dimethylaniline (0.25 g), hydroxybenzotriazole (0.41 g) in dimethylformide (DMF)/CH 2 Cl 2 (1:1, 20 ml) was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) (0.57 g).", "The mixture was stirred at 0-5° C. for about 30 minutes and then the temperature was slowly allowed to room temperature overnight.", "After evaporation of the solvents, the residue was partitioned between ethyl acetate (EtOAc) and water.", "EtOAc extract was washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ).", "The solvent was evaporated in vacuo to dryness.", "The residue was chromatographed on silica gel (40 g) using CHCl 3 /acetone= 19:1 as eluants, appropriate fractions were pooled, and solvents were removed in vacuo to dryness giving 350 mg of the above titled compound.", "TLC (silica gel: CHCl 3 /acetone=4:1, R f −0.77).", "[91] 91.", "b) L-[S-acetamidomethylpenicillaminyl-2,3-dimethyl anilide TFA salt [92] 92.", "[N-t-butoxycarbonyl-S-acetamidomethyl]-penicillaminyl-2,3-dimethylanilide was treated with 50% TFA in CH 2 Cl 2 (20 ml) for about 30 minutes Volatile substances were removed in vacuo to dryness.", "Trace of TFA was removed by co-evaporation with toluene several times.", "The TFA salt was dissolved in CHCl 3 (30 ml), treated with excess triethylamine, washed with water, dried (MgSO 4 ), and solvent was evaporated in vacuo to give free base.", "[93] 93.", "c) N-[2(R)-(t-Butoxycarbonyl)amino-3-triphenylmethylmercapto propyl]-L-[S-acetamidomethylpenicillaminyl-2,3-dimethylamilide [94] 94.", "To a stirred solution of 2(R)-t-butoxycarbonylamino-3-triphenylmethylmercaptopropanal (0.5 g;", "Example 1b) and L-[S-acetamidomethylpenicillaminyl-2,3-dimethylanilide TFA salt (0.3 g) in MeOH containing 1% acetic acid (HOAc) (10 ml) was added portionwise NaCNBH 3 (100 mg).", "The mixture was stirred at room temperature overnight.", "Most of the solvent was evaporated in vacuo to a small volume, which was partitioned between EtOAc and water.", "EtOAc layer was further washed with aqueous NaHCO 3 , water, and then dried (MgSO 4 ).", "After evaporation of solvent, the residue was chromatographed on silica gel (30 g) using CHCl 3 -acetone (19:1 to 9:1) as eluants.", "Appropriate fractions were pooled, and solvents were evaporated in vacuo to dryness giving 360 mg of the above titled compound.", "TLC (silica gel: CHCl 3 /acetone=9:1, R f =0.13.", "[95] 95.", "d) N-[2-(R)-Amino-3-mercaptopropyl]-L-penicillaminyl]-2,3-dimethylanilide cyclic disulfide [96] 96.", "To a stirred solution of N-[2(R)-(t-butoxycarbonyl) amino-3-triphenylmethylmercaptopropyl]-L-[S-acetamidomethyl penicillaminyl]-2,3-dimethylamilide (350 mg) in 50 ml 90% MeOH in water was added a solution of iodine (250 mg) in MeOH (5 ml).", "After 1 hour, most of the solvent was evaporated in vacuo to a small volume, diluted with water, extracted with EtOAc.", "EtoAc layer was washed with aqueous Na 2 S 2 O 3 , water, then dried (MgSO 4 ).", "Solvent was removed in vacuo to dryness (220 mg), treated with 90% aqueous TFA (ml) for about 30 minutes, and volatile substances were removed in vacuo to dryness.", "Crude product was purified by preparative HPLC giving 62 mg of the above titled compound as a white solid.", "M/e=340.2.", "EXAMPLE 4 Synthesis of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide, (Compound 28), 1-[2(R) -Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine, (Compound 30), and Bis-1,1′-2,2′-[2(R)-amino-3-mercaptopropyl]-2(S)-[2-mercaptoethyl)-4-(1-naphthoyl)-piperazinetetrasulfide, (Compound 29) [97] 97.", "a) Synthesis of 1-Benzyl-3(S)-benzyloxycarbonylmethyl piperazine-2,5-dione [98] 98.", "To an ice-cooled solution of BOC-aspartic acid β-benzyl ester (10 g), hydroxybenzotriazole (HOBT, 4.2 g), and N-benzylglycine ethyl ester (6.4 g) in 80 ml CH 2 Cl 2 was added a cold solution of dicyclohexylcarbodiimide (DCC, 7.1 g) in 20 ml CH 2 Cl 2 .", "The reaction was stirred for about 1 hour at 0-5° C., then overnight at room temperature.", "The precipitate was filtered off and the filtrate was evaporated in vacuo to dryness.", "The residue was partitioned between ethyl acetate and water.", "The organic layer was washed with 100 ml aqueous NaHCO 3 , water, then dried (MSO 4 ) .", "Solvent was removed in vacuo to dryness to give 16 g. TLC (silica gel: CHCl 3 /acetone= 9:1, R f =0.55).", "[99] 99.", "This was treated with 50% trifluoroacetic acid in CHCl 3 (40 ml) for about 1 hour and the volatile substances were removed in vacuo to dryness.", "The residue was partitioned between ethyl acetate and saturated aqueous NaHCO 3 .", "The organic layer was then dried (MgSO 4 ) and the solvent was evaporated in vacuo to give 10 g. TLC (silica gel, CHCl 3 /acetone=9:1, R f =0.14).", "[100] 100.", "b) Synthesis of 4-Benzyl-1-tert-butoxycarbonyl-2(S) -(2-hydroxyethyl) piperazine [101] 101.", "To an ice-cooled solution of the product from Step A (9.73 g) in 200 ml tetrahydrofuran (THF) was added portion wise a 50% mineral dispersion of lithium aluminum hydride (12.5 g) under a nitrogen atmosphere.", "The reaction mixture was refluxed overnight.", "After cooling in an ice bath, saturated aqueous Na 2 SO 4 was added dropwise to decompose excess LAH and the white slurry in THF was filtered through a diatomaceous earth pad.", "The filtrate was concentrated in vacuo to dryness and the residue was dissolved in dichloromethane (55 mg), treated with di-tert-butyl dicarbonate (5.9 g), and stirred for about 1 hour.", "Aqueous saturated NaHCO 3 (25 ml) was added and stirred for about 2 hours.", "The organic layer was washed with saturated sodium chloride and dried (MgSO 4 ).", "After evaporation of solvent, the residue was chromatographed on silica gel (160 g) using CHCl 3 /MeOH (19:1) as eluent.", "Appropriate fractions were pooled, and solvents were removed in vacuo to dryness, to give 8.7 g of a glass.", "TLC (silica gel: CHCl 3 /MeOH=9:1, R f =0.56).", "[102] 102.", "c) Synthesis of 1-tert-Butoxycarbonyl-2-(S)-(2-hydroxyethyl) piperazine [103] 103.", "The product from Step B (8.7 g) was dissolved in ethanol (35 ml) treated with Pd(OH) 2 -charcoal (0.8 g) and acetic acid (3 ml).", "Hydrogenation was carried out under 30 p.s.i. overnight.", "The reaction mixture was filtered through a diatomaceous earth pad and the solvent was removed in vacuo to dryness.", "[104] 104.", "d) Synthesis of 1-tert-Butoxycarbonyl-2(S)-(2-hydroxyethyl)-4-(1-naphthoyl) piperazine [105] 105.", "To a solution of the product from Step C (8.4 g) in acetonitrile (40 ml) was added 110 ml 1 N aqueous NaOH followed by a solution of 1-naphthoyl chloride (5.14 g) in acetonitrile (20 ml).", "After about 3 hours stirring, most of the acetonitrile was removed in vacuo and the remaining mixture was extracted with chloroform.", "It was dried (MgSO 4 ) and the solvent was removed in vacuo to dryness, to give 8.12 g. of product.", "TLC (silica gel: CHCl 3 /MeOH=9:1, R f = 0.64).", "[106] 106.", "e) Synthesis of 1-tert-Butoxycarbonyl-2(S)-(2-triphenylmethylthioethyl)-4-(1-naphthoyl)-piperazine [107] 107.", "To an ice-cooled solution of triphenylphosphine (0.53 g) in 5 ml dry THF was added dropwise a solution of diethylazodicarboxylate (DEAD, 0.25 g) in 2 ml THF.", "After stirring at 0-50° C. for about 30 minutes, a solution of the product from Step D (0.4 g) and triphenylmercaptan (0.55 g) in 10 ml THF was added dropwise.", "The mixture was stirred at 0-5° C. for about 1 hour and room temperature for about 1 hour.", "The solvent was evaporated in vacuo to dryness and the residue was chromatographed on silica gel (40 g) using CHCl 3 as eluent.", "Appropriate fractions were pooled and the solvent was removed in vacuo to dryness, to give a pale yellow foam 420 mg.", "Mass Spec (Electrospray) 665.2 (643+23(sodium)).", "TLC (silica gel: CHCl 3 /acetone=9:1 R f =0.53).", "[108] 108.", "f) Synthesis of 2(S)-(2-Triphenylmethylthioethyl)-4-(1-naphthoyl) piperazine [109] 109.", "To a stirred solution of the product from Step E (2.2 g) in 30 ml CH 2 Cl 2 was added 10 ml trifluoroacetic acid (TFA).", "The mixture was stirred for about 30 minutes.", "Volatile substances were removed in vacuo to dryness.", "The residue was dissolved in CHCl 3 (50 ml) and treated with excess triethylamine (4 ml).", "The mixture was washed with water, then dried (MgSO 4 ) and volatile substances were removed in vacuo to dryness, to give a pale yellow glass, 2.1 g;", "TLC (silica gel;", "CHCl 3 /MeOH=9:1, R f =0.63).", "[110] 110.", "g) Synthesis of 1-[2(R)-N-tert-Butoxycarbonylamino-3-triphenyl methylthiopropyl]-2(S)-(2-triphenylmethylthioethyl)-4-(1-naphthoyl)-piperazine [111] 111.", "To a solution of the product from Step F (0.9 g) and 2(R)-N-tert-butoxycarbonylamino-3-triphenylmethylthiopropanal (1.2 g) prepared according to the procedure of O. P. Goel, et al.", ", (Org.", "Syn.", "1988, 67, 69-75), in CH 2 Cl 2 (20 ml) containing 1% acetic acid, was added 4 g of molecular sieves 4 Å followed by portion wise addition of Na(OAc) 3 BH (1 g) over a 30 minutes period.", "After stirring for about 2 hours, the mixture was filtered and the filtrate was washed with water, 5% aqueous NaHCO 3 , water, and then dried (MgSO 4 ).", "The solvent was evaporated in vacuo to dryness, and the residue was chromatographed on silica gel (60 g) using CHCl 3 as an eluent.", "Appropriate fractions were pooled and solvent was removed in vacuo to dryness, to give 0.6 g white foam.", "TLC (silica gel, CHCl 3 /acetone=9:1;", "R f =0.55);", "Mass Spec (Electro Spray) 974.3.", "[112] 112.", "h) Synthesis of 1-[2(R)-amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide, (Compound 28), and Bis-1,1′-2,2′-[2(R)-Amino-3-mercaptopropyl]-2(S)-[2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-tetrasulfide, (Compound 29) [113] 113.", "To a stirred solution of the product from step g (0.7 g) in CHCl 3 /CH 3 OH (1:3, 60 ml) was added a solution of iodine in methanol (0.2 g in 5 ml).", "After stirring for about 40 minutes most of the solvents were removed in vacuo to dryness and the residue was partitioned between ethyl acetate (30 ml) and 5% aqueous Na 2 S 2 O 3 .", "The organic layer was washed with water, then dried (MgSO 4 ).", "After evaporation of solvent the residue was treated with 50% trifluoroacetic acid in dichloromethane (10 ml) for about 30 minutes.", "Volatile substances were removed in vacuo to dryness and the residue was triturated with ether and filtered.", "[114] 114.", "The crude product was subjected to preparative high performance liquid chromatography (HPLC) using a C 18 column and 0.1% aqueous TFA and CH 3 CN as the mobile phase.", "Earlier fractions (retention=5 minutes, CH 3 CN/0.1% aqueous TFA= 50:50, elution rate=1 ml/min) gave the white solid 1,2 cyclodisulfide;", "Mass.", "Spec.", "(Electrospray)=388.1.", "Later fractions (retention time=7.2 minutes using the same isocratic conditions) gave the dimer;", "Mass Spec.", "(Electrospray)=775.1 The ratio of cyclic disulfide and dimeric tetrasulfide was about 4 to 1.", "EXAMPLE 5 Alternative cyclization of compound 30 using immobilized oxidizing resin (EKATHIOX™ resin) or air.", "[115] 115.", "a) Synthesis of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) [116] 116.", "The product from Step G (450 mg) was treated for about 30 minutes with 50% TFA in CH 2 Cl 2 (10 ml) containing 1 ml triethylsilane.", "Volatile substances were then removed in vacuo to dryness.", "The residue was triturated with ether, filtered, then dried, resulting in 280 mg of 1-(2(R)-amino-3-mercaptopropyl]-2(S)-(2-mercaptoethyl)-4-(1-naphthoyl)-piperazine, (Compound 30).", "Mass spec (electrospray) 390.3 [117] 117.", "b) Cyclization of 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) to form 1-[2(R)-Amino-3-mercaptopropyl]-2(S)-2-mercaptoethyl)-4-(1-naphthoyl)-piperazine-1,2-cyclodisulfide (Compound 28) [118] 118.", "100 mg of the product from Step a) was dissolved in 10 ml aqueous CH 3 CN (H 2 O/CH 3 CN=7.3), and treated with 3 g of EKATHIOX™ resin (0.34 mmoles/gm).", "The mixture was stirred at room temperature for about 6 hours.", "The mixture was then filtered, the resin washed with aqueous methanol (1:3), and most of the organic solvent was removed in vacuo to a small volume.", "The concentrate was subjected to preparative HPLC using 0.1% aqueous TFA and CH 3 CN as mobile phase.", "Appropriate fractions were pooled and most of the solvents removed in vacuo to small volume.", "The concentrate was then lyophilized.", "[119] 119.", "Alternatively, the solution of 1-[2(R)-amino-3-mercaptopropyl]-2(S)-(2-mercaptoethyl)-4-(1-naphthoyl)-piperazine (Compound 30) in aqueous CH 3 CN was stirred with air in pH 6-8 range.", "In both instances the reaction mixture showed a distribution of the cyclic disulfide and the tetrasulfide dimer in the ratio of about 4 to 1.", "OTHER EMBODIMENTS [120] 120.", "It is to be understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims.", "Other aspects, advantages, and modifications are within the claims." ]
BACKGROUND OF THE INVENTION [0001] The present invention relates to a cellular phone comprising a central processing unit (CPU). [0002] A hand-held terminal or mobile terminal, for switching the frequency of a clock signal delivered from the side of an application program, is disclosed in JP-A NO. 73237/1999 (Heisei 11). [0003] Further, in JP-A No. 148475/2000, there is disclosed a computer for a mobile unit, capable of switching a clock frequency to a high-speed mode frequency higher than a normal frequency when conditions, such as power source voltage, ambient temperature, and so forth, are satisfied. [0004] In the case of the conventional technology described above, speed control of a clock signal has been implemented by an application program or has been dependent on the conditions such as power source voltage, ambient temperature, and so forth, so that there is no room for interposition of the will of a user in switching the speed of the clock signal. Further, if the CPU is driven at a high frequency, there has been a tendency toward an increase in current consumption although a processing speed is enhanced. With a cellular phone, in particular, since its battery capacity is small, there has been a risk of premature depletion of the battery capacity occurring when the clock signal has been automatically switched over to the high-speed side without knowledge of the user. SUMMARY OF THE INVENTION [0005] To attain both enhancement in processing speed and reduction in current consumption, it is an object of the invention to provide a mobile terminal comprising clock control means capable of changing the frequency of a clock signal received from an oscillator under control by a central processing unit, and converting an operation frequency of the central processing unit to a different frequency, wherein a clock signal at the different frequency as converted by the clock control means becomes a clock signal of the central processing unit. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 is a block diagram showing the configuration of a first embodiment of a cellular phone according to the invention; [0007] FIG. 2 is a block diagram showing the configuration of a second embodiment of a cellular phone according to the invention; [0008] FIG. 3 is a block diagram showing the configuration of a third embodiment of a cellular phone according to the invention; [0009] FIG. 4 is a block diagram showing the configuration of a fourth embodiment of a cellular phone according to the invention; and [0010] FIG. 5 is a graph showing the relationship between an operation frequency of a central processing unit of the cellular phone according to the first to fourth embodiments, respectively, and current consumption. [0011] Other and further objects, features and advantages of the invention will appear more fully from the following description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] A first embodiment of a cellular phone according to the invention is described hereinafter with reference to FIGS. 1 and 5 . FIG. 1 is a block diagram showing the internal configuration of the cellular phone according to the first embodiment. [0013] A central processing unit (CPU) 100 controls the operation of the cellular phone in accordance with a control program stored in a memory 110 . The CPU 100 performs operation in accordance with an input pushbutton as pressed via an operation panel (input pushbutton group) 120 , executing processing in response to the input pushbutton as pressed. [0014] Upon dialing, a telephone number as inputted from the operation panel 120 is shown on a display unit 130 , a speech signal delivered from a speech input unit (microphone) 140 is sent out in the form of radio waves from an antenna 160 to the outside via a transmit/receive unit 150 in accordance with a transmission directive delivered from the operation panel 120 . [0015] At the time of signal reception, radio waves from the outside are received by the antenna 160 , and upon recognition by the transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone, speech is delivered from a speech output unit (speaker) 170 . [0016] The CPU 100 receives a clock signal from an oscillator 180 through the intermediary of a clock controller 200 . Because an operation frequency of the CPU 100 is dependent on the frequency of the clock signal as received, a processing speed of the CPU 100 is regulated by the frequency of the clock signal. The clock controller 200 converts the frequency of the clock signal into any suitable frequency by use of a PLL (Phase Locked Loop) circuit under control by the CPU 100 , and the clock signal is delivered to the CPU 100 as a clock signal of the CPU 100 . The frequency of the clock signal delivered to the CPU 100 becomes the operation frequency of the CPU 100 . [0017] FIG. 5 is a graph showing the relationship between the operation frequency and current consumption. In proportion as the frequency of the clock signal is changed to a higher frequency, the operation frequency of the CPU 100 becomes higher, thereby enhancing the processing speed of the CPU 100 although current consumption increases. [0018] With the present embodiment, when executing a specific processing, the frequency of the clock signal of the CPU 100 is caused to change to a higher frequency, thereby enhancing the processing speed. Upon completion of the execution of the specific processing, the frequency of the clock signal of the CPU 100 is caused to change to a lower frequency, thereby reducing current consumption. In the initial condition at the time when power is turned on, the frequency of the clock signal of the CPU 100 is set to a low frequency in order to reduce current consumption. [0019] Herein, the specific processing refers to, for example, processing for image decoding, address retrieval processing, and application processing such as kana-kanji conversion processing used in entering characters. These processing often have effects on the response of the user. [0020] With the present embodiment, the user can change the operation frequency of the CPU 100 by changing the output frequency of the clock controller 200 at will with the use of a clock manipulation unit 300 connected with the CPU 100 . [0021] If the user enters a request for change via the clock manipulation unit 300 , the CPU 100 receives an input from the clock manipulation unit 300 , and controls the clock controller 200 , thereby controlling a clock frequency to be fed to the CPU 100 . That is, in response to the input from the clock manipulation unit 300 , the frequency of the clock signal to be fed to the CPU 100 is set. [0022] Further, with the present embodiment, depending on an application to be used, and use environments, the user can change the frequency of the clock signal in every processing. For example, if the user wants to increase the processing speed of the CPU 100 , the frequency of the clock signal can be raised, and if the user wants to reduce current consumption, the frequency of the clock signal can be changed to a lower frequency. By virtue of such a function as described, the user can set the frequency of the clock signal as appropriate at will depending on the user's use environments, such as the user' desire to execute high speed processing, or to use the cellular phone for many hours, the amount of the actual battery capacity that remains in a battery being small, and so forth, so that operability can be enhanced. [0023] In FIG. 1 , the clock manipulation unit 300 is shown as a single pushbutton (clock manipulation pushbutton), but may be made up of a plurality of keys instead. In order to implement the clock manipulation unit 300 with the single pushbutton, for example, the lowest frequency is set as the initial condition of the frequency of the clock signal, thereby carrying out control such that every time when the single pushbutton is once operated, the frequency of the clock signal of the CPU 100 is changed to sequentially higher frequencies by stages. The frequency is changed cyclically, and if the frequency of the clock signal of the CPU 100 is changed to the highest frequency, upon operation of the single pushbutton the next time, the frequency of the clock signal of the CPU 100 reverts to the lowest frequency. Thus, every time when the single pushbutton is operated, the output frequency of the clock controller 200 can be changed, thereby enabling the operation frequency of the CPU 100 to be changed. [0024] The CPU 100 causes the display unit 130 to display a numerical value of the frequency after changed in such a way as to explicitly advise the user of the frequency of the clock signal after changed. Since it is sufficient for such display to indicate simply which stage the processing speed of the CPU 100 is in, indication of a specific numerical value of the frequency is not necessarily required. Numbers to indicate respective stages, such as 1, 2 , 3 . . . , or characters such as high, middle, low, etc. may be displayed. Alternatively, the respective stages of the processing speed may be displayed in number of stars, exhibiting one star on the display unit 130 for the lowest speed, increasing the number of stars exhibited on the display unit 130 in ascending order of the stage. Otherwise, the status of the processing speed may be displayed with the use of a bar graph, icons, and so forth. [0025] Further, for changing the output frequency of the clock controller 200 at the user's will, there may be adopted a method whereby an operation menu directing change of the frequency of the clock signal is caused to be displayed on the display unit 130 without the use of the clock manipulation pushbutton, and the user selects or directs at will the output frequency of the clock controller 200 by use of the operation panel 120 , thereby changing the operation frequency of the CPU 100 . In such a case, the operation panel 120 functions as the clock manipulation unit 300 , so that the clock manipulation unit 300 can be omitted. [0026] Now, a second embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 2 . FIG. 2 is a block diagram showing the internal configuration of the cellular phone according to the second embodiment. [0027] With the present embodiment, a central processing unit (CPU) is made up so as to be divided into a first central processing unit 400 concerned with transmit/receive of signals, and a second central processing unit 410 handling processing that has effects on the response of a user. In FIG. 2 , blocks denoted by the same reference numerals as those in FIG. 1 correspond to those blocks of the first embodiment, having the same functions. [0028] The first central processing unit 400 controls operation concerned with transmit/receive by the cellular phone in accordance with a control program stored in a first memory 420 , and the second central processing unit 410 controls operation concerned with processing that has effects on the response of a user in accordance with a control program stored in a second memory 430 . More specifically, the second central processing unit 410 controls operation concerned with processing of an application program. [0029] A clock signal from an oscillator 180 is directly delivered to the first central processing unit 400 as a clock signal. Meanwhile, a clock signal at any suitable frequency converted by control of the second central processing unit 410 is delivered to the second central processing unit 410 through the intermediary of a clock controller 200 . [0030] With such a configuration as described, when executing a specific processing, the frequency of the clock signal delivered to the second central processing unit 410 can be changed to a high frequency, thereby enhancing a processing speed, and upon completion of execution of the processing that has effects on the response of the user, the frequency of the clock signal delivered to the second central processing unit 410 can be changed to a low frequency, thereby reducing current consumption. [0031] For example, during a standby (waiting) period for communications by the cellular phone, the first central processing unit 400 is in intermittent operation to receive radio waves from the outside via an antenna 160 , executing processing for recognition by the transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone. In this case, the frequency of the clock signal delivered to the second central processing unit 410 is changed to a low frequency to thereby reduce current consumption. As shown FIG. 5 , the relationship between an operation frequency and current consumption is such that in proportion as the operation frequency becomes higher, the current consumption increases while in proportion as the operation frequency becomes lower, the current consumption decreases. [0032] The cellular phone shown in FIG. 2 further comprises a power supply controller 500 . The power supply controller 500 controls power to be supplied from a battery 510 to the second central processing unit 410 in response to control by the first central processing unit 400 . For example, during a standby (waiting) period for communications by the cellular phone or upon completion of the processing by the second central processing unit 410 , the power supply controller 500 can turn off power to be supplied to the second central processing unit 410 in response to control by the first central processing unit 400 . Since the second central processing unit 410 handles application, its power consumption at the time of processing is large, and consequently, effective saving in power can be attained by controlling the power supplied. [0033] Next, a third embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 3 . [0034] The cellular phone shown in FIG. 3 comprises a battery voltage detector 600 in place of the power supply controller 500 incorporated in the cellular phone shown in FIG. 2 . In FIG. 3 , blocks denoted by the same reference numerals as those in FIG. 2 have the same functions as those of the blocks of the second embodiment, omitting therefore description thereof. [0035] The battery voltage detector 600 detects a voltage of a battery 510 . A first central processing unit 400 determines whether or not the voltage detected is lower than a predetermined value. In the case where it is determined that the amount of the actual battery capacity that remains in the battery 510 is less than a predetermined amount, the frequency of a clock signal delivered to a second central processing unit 410 is changed to a lower frequency even when executing a specific processing, thereby reduging current consumption. Hence, it is possible to effect control so as to reduce current consumption in case that the amount of the actual battery capacity that remains in the battery becomes small, thereby prolonging operable time of the cellular phone. [0036] Further, a fourth embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 4 . FIG. 4 is a block diagram showing the internal configuration of the cellular phone of a folded structure, according to the fourth embodiment. In FIG. 4 , blocks denoted by the same reference numerals as those in FIGS. 2 and 3 , respectively, have the same functions as those of the blocks of the second and third embodiments, respectively, omitting therefore description thereof. [0037] The cellular phone shown in FIG. 4 comprises a folding condition detector 700 for detecting whether the cellular phone is in a folded (closed) condition or in an unfolded (open) condition. [0038] With the cellular phone according to the present embodiment, a first display unit 710 and a second display unit 720 are added to a first central processing unit 400 and a second central processing unit 410 , respectively. The first display unit 710 is disposed at a position as can be seen by a user even in the folded condition. The second display unit 720 is disposed at the folded-down side of the cellular phone. [0039] Since the operation of the cellular phone in the open condition is the same as that of the cellular phone according to the second and third embodiments, respectively, the operation of the cellular phone in the closed condition is described hereinafter. [0040] Normally, in the closed condition, the cellular phone is often on standby (waiting) for cellular phone communications, and the first central processing unit 400 is in intermittent operation to receive radio waves from the outside via an antenna 160 , executing processing for recognition through the intermediary of a transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone. Meanwhile, since a load on the second central processing unit 410 is light at this point in time, the frequency of a clock signal delivered to the second central processing unit 410 can be changed to a low frequency, thereby reducing power consumption. When executing a specific processing even in the closed condition, the frequency of the clock signal delivered to the second central processing unit 410 is caused to change to a higher frequency, thereby enhancing a processing speed, and upon completion of execution of the specific processing, the frequency of the clock signal is caused to change to a low frequency, thereby reducing current consumption. [0041] Further, in the closed condition, the user is unable to see the second display unit 720 . Accordingly, as for processing concerning the second display unit 720 , upon detection of the closed condition, the frequency of the clock signal delivered to the second central processing unit 410 is caused to change to a low frequency, thereby enabling current consumption to be reduced. [0042] Furthermore, even when executing the specific processing, the frequency of the clock signal delivered to the second central processing unit 410 may be changed to a low frequency in the case of the closed condition. In the case of the cellular phone being in the closed condition, the user does not look at a display screen of the cellular phone, and is often in no hurry to do processing. Accordingly, in the case of the closed condition, processing can be executed while reducing power consumption by changing the frequency of the clock signal to a lower frequency. When the cellular phone is shifted to the open condition, the processing speed is enhanced by changing the frequency of the clock signal delivered to the second central processing unit 410 to a higher frequency. [0043] The cellular phone shown in FIG. 4 further comprises a lighting controller 800 for controlling backlight of the second display unit 720 . Since the user is unable to see the second display unit 720 in the folded condition, further reduction in power consumption can be attained by turning off the backlight of the second display unit 720 . [0044] In addition, the power supply controller 500 shown in FIG. 2 or the battery voltage detector 600 shown in FIG. 3 may be added to the cellular phone according to the present embodiment. In such a case, when the amount of the actual battery capacity that remains in the battery 510 is less than a predetermined amount, power consumption can be reduced and waiting time can be extended by implementing control such that the backlight of the second display 720 is turned off even in the open condition. [0045] Still further, the operability of the cellular phone can be improved by providing the cellular phone shown in FIGS. 2 through 4 , respectively, with the clock manipulation unit 300 shown FIG. 1 , thereby enabling the user to change the frequency of the clock signal as with the case of the first embodiment. Also, the operation panel 120 may have the function of the clock manipulation unit 300 . [0046] The respective embodiments described hereinbefore may be carried out singly or in combination as appropriate. [0047] With the embodiments described hereinbefore, the clock controller, the memories, and so forth are disposed outside of the central processing unit, however, these components together with the central processing unit may be integrated so as to be incorporated in one chip. [0048] As described in the foregoing, with the embodiments of the invention, it is possible to attain both enhancement in the processing speed and reduction in the power consumption. [0049] The foregoing invention has been described in terms of preferred embodiments. However, those skilled, in the art will recognize that many variations of such embodiments exist. Such variations are intended to be within the scope of the present invention and the appended claims.
There is provided a cellular phone taking into consideration enhancement in processing speed and reduction in current consumption, and the cellular phone comprises a processing unit capable of executing plural kinds of processing, an oscillator for generating a clock signal to be fed to the processing unit, and a clock controller for converting the frequency of the clock signal received from the oscillator, wherein the clock controller changes the frequency of the clock signal for each of the plural kinds of the processing in response to the control by the central processing unit.
Identify and summarize the most critical technical features from the given patent document.
[ "BACKGROUND OF THE INVENTION [0001] The present invention relates to a cellular phone comprising a central processing unit (CPU).", "[0002] A hand-held terminal or mobile terminal, for switching the frequency of a clock signal delivered from the side of an application program, is disclosed in JP-A NO.", "73237/1999 (Heisei 11).", "[0003] Further, in JP-A No. 148475/2000, there is disclosed a computer for a mobile unit, capable of switching a clock frequency to a high-speed mode frequency higher than a normal frequency when conditions, such as power source voltage, ambient temperature, and so forth, are satisfied.", "[0004] In the case of the conventional technology described above, speed control of a clock signal has been implemented by an application program or has been dependent on the conditions such as power source voltage, ambient temperature, and so forth, so that there is no room for interposition of the will of a user in switching the speed of the clock signal.", "Further, if the CPU is driven at a high frequency, there has been a tendency toward an increase in current consumption although a processing speed is enhanced.", "With a cellular phone, in particular, since its battery capacity is small, there has been a risk of premature depletion of the battery capacity occurring when the clock signal has been automatically switched over to the high-speed side without knowledge of the user.", "SUMMARY OF THE INVENTION [0005] To attain both enhancement in processing speed and reduction in current consumption, it is an object of the invention to provide a mobile terminal comprising clock control means capable of changing the frequency of a clock signal received from an oscillator under control by a central processing unit, and converting an operation frequency of the central processing unit to a different frequency, wherein a clock signal at the different frequency as converted by the clock control means becomes a clock signal of the central processing unit.", "BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 is a block diagram showing the configuration of a first embodiment of a cellular phone according to the invention;", "[0007] FIG. 2 is a block diagram showing the configuration of a second embodiment of a cellular phone according to the invention;", "[0008] FIG. 3 is a block diagram showing the configuration of a third embodiment of a cellular phone according to the invention;", "[0009] FIG. 4 is a block diagram showing the configuration of a fourth embodiment of a cellular phone according to the invention;", "and [0010] FIG. 5 is a graph showing the relationship between an operation frequency of a central processing unit of the cellular phone according to the first to fourth embodiments, respectively, and current consumption.", "[0011] Other and further objects, features and advantages of the invention will appear more fully from the following description.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] A first embodiment of a cellular phone according to the invention is described hereinafter with reference to FIGS. 1 and 5 .", "FIG. 1 is a block diagram showing the internal configuration of the cellular phone according to the first embodiment.", "[0013] A central processing unit (CPU) 100 controls the operation of the cellular phone in accordance with a control program stored in a memory 110 .", "The CPU 100 performs operation in accordance with an input pushbutton as pressed via an operation panel (input pushbutton group) 120 , executing processing in response to the input pushbutton as pressed.", "[0014] Upon dialing, a telephone number as inputted from the operation panel 120 is shown on a display unit 130 , a speech signal delivered from a speech input unit (microphone) 140 is sent out in the form of radio waves from an antenna 160 to the outside via a transmit/receive unit 150 in accordance with a transmission directive delivered from the operation panel 120 .", "[0015] At the time of signal reception, radio waves from the outside are received by the antenna 160 , and upon recognition by the transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone, speech is delivered from a speech output unit (speaker) 170 .", "[0016] The CPU 100 receives a clock signal from an oscillator 180 through the intermediary of a clock controller 200 .", "Because an operation frequency of the CPU 100 is dependent on the frequency of the clock signal as received, a processing speed of the CPU 100 is regulated by the frequency of the clock signal.", "The clock controller 200 converts the frequency of the clock signal into any suitable frequency by use of a PLL (Phase Locked Loop) circuit under control by the CPU 100 , and the clock signal is delivered to the CPU 100 as a clock signal of the CPU 100 .", "The frequency of the clock signal delivered to the CPU 100 becomes the operation frequency of the CPU 100 .", "[0017] FIG. 5 is a graph showing the relationship between the operation frequency and current consumption.", "In proportion as the frequency of the clock signal is changed to a higher frequency, the operation frequency of the CPU 100 becomes higher, thereby enhancing the processing speed of the CPU 100 although current consumption increases.", "[0018] With the present embodiment, when executing a specific processing, the frequency of the clock signal of the CPU 100 is caused to change to a higher frequency, thereby enhancing the processing speed.", "Upon completion of the execution of the specific processing, the frequency of the clock signal of the CPU 100 is caused to change to a lower frequency, thereby reducing current consumption.", "In the initial condition at the time when power is turned on, the frequency of the clock signal of the CPU 100 is set to a low frequency in order to reduce current consumption.", "[0019] Herein, the specific processing refers to, for example, processing for image decoding, address retrieval processing, and application processing such as kana-kanji conversion processing used in entering characters.", "These processing often have effects on the response of the user.", "[0020] With the present embodiment, the user can change the operation frequency of the CPU 100 by changing the output frequency of the clock controller 200 at will with the use of a clock manipulation unit 300 connected with the CPU 100 .", "[0021] If the user enters a request for change via the clock manipulation unit 300 , the CPU 100 receives an input from the clock manipulation unit 300 , and controls the clock controller 200 , thereby controlling a clock frequency to be fed to the CPU 100 .", "That is, in response to the input from the clock manipulation unit 300 , the frequency of the clock signal to be fed to the CPU 100 is set.", "[0022] Further, with the present embodiment, depending on an application to be used, and use environments, the user can change the frequency of the clock signal in every processing.", "For example, if the user wants to increase the processing speed of the CPU 100 , the frequency of the clock signal can be raised, and if the user wants to reduce current consumption, the frequency of the clock signal can be changed to a lower frequency.", "By virtue of such a function as described, the user can set the frequency of the clock signal as appropriate at will depending on the user's use environments, such as the user'", "desire to execute high speed processing, or to use the cellular phone for many hours, the amount of the actual battery capacity that remains in a battery being small, and so forth, so that operability can be enhanced.", "[0023] In FIG. 1 , the clock manipulation unit 300 is shown as a single pushbutton (clock manipulation pushbutton), but may be made up of a plurality of keys instead.", "In order to implement the clock manipulation unit 300 with the single pushbutton, for example, the lowest frequency is set as the initial condition of the frequency of the clock signal, thereby carrying out control such that every time when the single pushbutton is once operated, the frequency of the clock signal of the CPU 100 is changed to sequentially higher frequencies by stages.", "The frequency is changed cyclically, and if the frequency of the clock signal of the CPU 100 is changed to the highest frequency, upon operation of the single pushbutton the next time, the frequency of the clock signal of the CPU 100 reverts to the lowest frequency.", "Thus, every time when the single pushbutton is operated, the output frequency of the clock controller 200 can be changed, thereby enabling the operation frequency of the CPU 100 to be changed.", "[0024] The CPU 100 causes the display unit 130 to display a numerical value of the frequency after changed in such a way as to explicitly advise the user of the frequency of the clock signal after changed.", "Since it is sufficient for such display to indicate simply which stage the processing speed of the CPU 100 is in, indication of a specific numerical value of the frequency is not necessarily required.", "Numbers to indicate respective stages, such as 1, 2 , 3 .", ", or characters such as high, middle, low, etc.", "may be displayed.", "Alternatively, the respective stages of the processing speed may be displayed in number of stars, exhibiting one star on the display unit 130 for the lowest speed, increasing the number of stars exhibited on the display unit 130 in ascending order of the stage.", "Otherwise, the status of the processing speed may be displayed with the use of a bar graph, icons, and so forth.", "[0025] Further, for changing the output frequency of the clock controller 200 at the user's will, there may be adopted a method whereby an operation menu directing change of the frequency of the clock signal is caused to be displayed on the display unit 130 without the use of the clock manipulation pushbutton, and the user selects or directs at will the output frequency of the clock controller 200 by use of the operation panel 120 , thereby changing the operation frequency of the CPU 100 .", "In such a case, the operation panel 120 functions as the clock manipulation unit 300 , so that the clock manipulation unit 300 can be omitted.", "[0026] Now, a second embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 2 .", "FIG. 2 is a block diagram showing the internal configuration of the cellular phone according to the second embodiment.", "[0027] With the present embodiment, a central processing unit (CPU) is made up so as to be divided into a first central processing unit 400 concerned with transmit/receive of signals, and a second central processing unit 410 handling processing that has effects on the response of a user.", "In FIG. 2 , blocks denoted by the same reference numerals as those in FIG. 1 correspond to those blocks of the first embodiment, having the same functions.", "[0028] The first central processing unit 400 controls operation concerned with transmit/receive by the cellular phone in accordance with a control program stored in a first memory 420 , and the second central processing unit 410 controls operation concerned with processing that has effects on the response of a user in accordance with a control program stored in a second memory 430 .", "More specifically, the second central processing unit 410 controls operation concerned with processing of an application program.", "[0029] A clock signal from an oscillator 180 is directly delivered to the first central processing unit 400 as a clock signal.", "Meanwhile, a clock signal at any suitable frequency converted by control of the second central processing unit 410 is delivered to the second central processing unit 410 through the intermediary of a clock controller 200 .", "[0030] With such a configuration as described, when executing a specific processing, the frequency of the clock signal delivered to the second central processing unit 410 can be changed to a high frequency, thereby enhancing a processing speed, and upon completion of execution of the processing that has effects on the response of the user, the frequency of the clock signal delivered to the second central processing unit 410 can be changed to a low frequency, thereby reducing current consumption.", "[0031] For example, during a standby (waiting) period for communications by the cellular phone, the first central processing unit 400 is in intermittent operation to receive radio waves from the outside via an antenna 160 , executing processing for recognition by the transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone.", "In this case, the frequency of the clock signal delivered to the second central processing unit 410 is changed to a low frequency to thereby reduce current consumption.", "As shown FIG. 5 , the relationship between an operation frequency and current consumption is such that in proportion as the operation frequency becomes higher, the current consumption increases while in proportion as the operation frequency becomes lower, the current consumption decreases.", "[0032] The cellular phone shown in FIG. 2 further comprises a power supply controller 500 .", "The power supply controller 500 controls power to be supplied from a battery 510 to the second central processing unit 410 in response to control by the first central processing unit 400 .", "For example, during a standby (waiting) period for communications by the cellular phone or upon completion of the processing by the second central processing unit 410 , the power supply controller 500 can turn off power to be supplied to the second central processing unit 410 in response to control by the first central processing unit 400 .", "Since the second central processing unit 410 handles application, its power consumption at the time of processing is large, and consequently, effective saving in power can be attained by controlling the power supplied.", "[0033] Next, a third embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 3 .", "[0034] The cellular phone shown in FIG. 3 comprises a battery voltage detector 600 in place of the power supply controller 500 incorporated in the cellular phone shown in FIG. 2 .", "In FIG. 3 , blocks denoted by the same reference numerals as those in FIG. 2 have the same functions as those of the blocks of the second embodiment, omitting therefore description thereof.", "[0035] The battery voltage detector 600 detects a voltage of a battery 510 .", "A first central processing unit 400 determines whether or not the voltage detected is lower than a predetermined value.", "In the case where it is determined that the amount of the actual battery capacity that remains in the battery 510 is less than a predetermined amount, the frequency of a clock signal delivered to a second central processing unit 410 is changed to a lower frequency even when executing a specific processing, thereby reduging current consumption.", "Hence, it is possible to effect control so as to reduce current consumption in case that the amount of the actual battery capacity that remains in the battery becomes small, thereby prolonging operable time of the cellular phone.", "[0036] Further, a fourth embodiment of a cellular phone according to the invention is described hereinafter with reference to FIG. 4 .", "FIG. 4 is a block diagram showing the internal configuration of the cellular phone of a folded structure, according to the fourth embodiment.", "In FIG. 4 , blocks denoted by the same reference numerals as those in FIGS. 2 and 3 , respectively, have the same functions as those of the blocks of the second and third embodiments, respectively, omitting therefore description thereof.", "[0037] The cellular phone shown in FIG. 4 comprises a folding condition detector 700 for detecting whether the cellular phone is in a folded (closed) condition or in an unfolded (open) condition.", "[0038] With the cellular phone according to the present embodiment, a first display unit 710 and a second display unit 720 are added to a first central processing unit 400 and a second central processing unit 410 , respectively.", "The first display unit 710 is disposed at a position as can be seen by a user even in the folded condition.", "The second display unit 720 is disposed at the folded-down side of the cellular phone.", "[0039] Since the operation of the cellular phone in the open condition is the same as that of the cellular phone according to the second and third embodiments, respectively, the operation of the cellular phone in the closed condition is described hereinafter.", "[0040] Normally, in the closed condition, the cellular phone is often on standby (waiting) for cellular phone communications, and the first central processing unit 400 is in intermittent operation to receive radio waves from the outside via an antenna 160 , executing processing for recognition through the intermediary of a transmit/receive unit 150 that the radio waves received are radio waves corresponding to a telephone number dedicated to the present cellular phone.", "Meanwhile, since a load on the second central processing unit 410 is light at this point in time, the frequency of a clock signal delivered to the second central processing unit 410 can be changed to a low frequency, thereby reducing power consumption.", "When executing a specific processing even in the closed condition, the frequency of the clock signal delivered to the second central processing unit 410 is caused to change to a higher frequency, thereby enhancing a processing speed, and upon completion of execution of the specific processing, the frequency of the clock signal is caused to change to a low frequency, thereby reducing current consumption.", "[0041] Further, in the closed condition, the user is unable to see the second display unit 720 .", "Accordingly, as for processing concerning the second display unit 720 , upon detection of the closed condition, the frequency of the clock signal delivered to the second central processing unit 410 is caused to change to a low frequency, thereby enabling current consumption to be reduced.", "[0042] Furthermore, even when executing the specific processing, the frequency of the clock signal delivered to the second central processing unit 410 may be changed to a low frequency in the case of the closed condition.", "In the case of the cellular phone being in the closed condition, the user does not look at a display screen of the cellular phone, and is often in no hurry to do processing.", "Accordingly, in the case of the closed condition, processing can be executed while reducing power consumption by changing the frequency of the clock signal to a lower frequency.", "When the cellular phone is shifted to the open condition, the processing speed is enhanced by changing the frequency of the clock signal delivered to the second central processing unit 410 to a higher frequency.", "[0043] The cellular phone shown in FIG. 4 further comprises a lighting controller 800 for controlling backlight of the second display unit 720 .", "Since the user is unable to see the second display unit 720 in the folded condition, further reduction in power consumption can be attained by turning off the backlight of the second display unit 720 .", "[0044] In addition, the power supply controller 500 shown in FIG. 2 or the battery voltage detector 600 shown in FIG. 3 may be added to the cellular phone according to the present embodiment.", "In such a case, when the amount of the actual battery capacity that remains in the battery 510 is less than a predetermined amount, power consumption can be reduced and waiting time can be extended by implementing control such that the backlight of the second display 720 is turned off even in the open condition.", "[0045] Still further, the operability of the cellular phone can be improved by providing the cellular phone shown in FIGS. 2 through 4 , respectively, with the clock manipulation unit 300 shown FIG. 1 , thereby enabling the user to change the frequency of the clock signal as with the case of the first embodiment.", "Also, the operation panel 120 may have the function of the clock manipulation unit 300 .", "[0046] The respective embodiments described hereinbefore may be carried out singly or in combination as appropriate.", "[0047] With the embodiments described hereinbefore, the clock controller, the memories, and so forth are disposed outside of the central processing unit, however, these components together with the central processing unit may be integrated so as to be incorporated in one chip.", "[0048] As described in the foregoing, with the embodiments of the invention, it is possible to attain both enhancement in the processing speed and reduction in the power consumption.", "[0049] The foregoing invention has been described in terms of preferred embodiments.", "However, those skilled, in the art will recognize that many variations of such embodiments exist.", "Such variations are intended to be within the scope of the present invention and the appended claims." ]
STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. BACKGROUND OF THE INVENTION Strike and interceptor aircraft operating in a hostile environment need a wide variety of increasingly sophisticated devices to assure their survival. Air or ground launched radar or infrared guided rocket propelled missiles can take a fearsome toll if their presence is not detected soon enough. When an early enough detection of these incoming missiles positively can be made, evasive action, flares, electronic counter measures, etc. can and greatly do reduce their effectiveness. Early warning systems that detect UV from the missile plume require large area, wide field of view detectors. In addition to the need for being highly reliable and compact in size it is highly desirable that the detectors be sensitive in the region of the missile plumes+ UV radiation, from 230 to 280 nanometers, to reduce false alarms. Contemporary filters that use absorption type materials are expensive since they require large single crystals of nickel sulphate or the like. In addition, the solar-blind photomultiplier tubes that have been used with the large crystals also are expensive. As a consequence, technology and funding constraints may limit aircraft from having an appropriate detector in some high technology combat zones. Thus, a continuing need exists in the state of the art for a large area, wide field of view detector of the UV radiation in a missile plume to assure the timely warning of an incoming missile. SUMMARY OF THE INVENTION The present invention is directed to providing a means for detecting the UV radiation of an incoming missile plume. A wide field of view detector has a coating that blocks some impinging radiation yet passes the UV radiation of interest that is radiated from an incoming missile plume. A material within the detector is stimulated by the incoming UV radiation to shift to fluorescent emissions which are outside the passband of the UV radiation. A second coating on an opposite wall of the detector passes the fluorescent emissions to a photomultiplier tube sensitive to the fluorescent emissions. A prime object of the invention is to provide an improved detector of UV radiation emanating from a missile plume. Another object is to provide a UV radiation detector having a pair of coatings on opposite side of a container filled with a material sensitive to impinging UV radiations to shift to responsive fluorescent emissions. Still another object of the invention is to provide for an improved detector of the UV radiation emanating from a missile plume that relies upon less costly photomultiplier tubes sensitive to radiation in the fluorescent spectrum. Yet a further object is to provide for an improvement in a UV detector that has a wide area, wide field of view detection capability. Still yet another further object is to provide for an apparatus for UV detection that is compact and of reduced cost making it attractive for wide spread application. These and other objects of the invention will become more readily apparent from the ensuing specification and appended claims when taken in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic depiction of the principle constituents of the invention. FIG. 2 depicts the passbands of the detector coatings S 1 and S 2 . FIG. 3 shows an energy level diagram with electronic transmissions of potassium. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and in particular FIG. 1, a large area, wide field of view detector apparatus 10 has been designed to detect the UV radiation that is emitted from the missile plume of an incoming missile. A hollow container 15 is disposed adjacent to a photomultiplier tube 30 . The pillbox-like container is fabricated from a section 16 of a quartz tube that has a pair of quartz plate caps 17 and 18 fused in place to form a cylinder closing a chamber 19 . The container has a duct, not shown, to allow introduction of a gas as will be elaborated on below and suitable valves and piping must also be provided to allow the introduction of the gas into chamber 19 . An upper surface of cap 17 is provided with a coating S 1 which passes only a spectral region Δλ 1 that lies between λ 1 and λ 2 , see FIG. 2 . The transmission characteristic of the material S 1 is depicted as being square in shape. This is for purposes of demonstration only, it being realized that a certain amount of curvature is inherent. The coating can be a laminate of a first layer which has a low pass characteristic and a second layer which has a high pass characteristic. Both of these characteristics are known to be curved, however; for purposes of clarification, the passband is depicted as being square with lower and upper limits of 230 nm and 280 nm. In other words only solar blind energy can enter into container 15 . Coatings having a bandwidth capability as called for above are well within the purview of the current state of the art. Numerous laboratories provide such coatings by conventional vapor deposition techniques once the desired passbands are known. A typical laboratory having such a capability is the Optical Coating Laboratory Incorporated in Santa Rosa, Calif. This laboratory routinely provides such coatings upon request. Other laboratories are readily available nation wide to provide similar services. An outer surface on cap 18 is provided with a coating S 2 . This coating transmits only the wavelength region from λ 3 to λ 4 , a spectral region Δλ 2 . This region encompasses all emitted fluorescent photons but does not overlap the passband Δλ 1 . Since transmission bands Δλ 1 and Δλ 2 do not overlap, container 15 is completely opaque to all wavelengths incident on it. In this case, the bandwidth Δλ 2 may span a range of between 740 nm and 790 nm. The coating S 2 like coating S1 is fabricated by a suitably equipped lab in accordance with well established techniques to provide this passband. Operation to provide a responsive signal at the output of photomultipler tube 30 requires that there be a wavelength shifting medium within chamber 19 . In other words, photons of UV energy passing through coating S1 are shifted to longer wavelengths by the proper medium contained in chamber 19 . This wavelength shifting or converting material may be a gas liquid or a solid and should have the following characteristics. First it absorbs all the photons that pass through surface S1. Second it fluoresces with large values of quantum efficiency with emission of a few wavelengths. Third the spectral region Δλ 1 should be removed from the spectral region Δλ 2 for ease of discrimination. For this reason coating S2 applied to the surface of cap 18 has a passband Δλ 2 that encompasses all the emitted fluorescent photons of the material contained within chamber 19 . Photomultiplier tube 30 behind coating S2 is selected to be sensitive only to the spectral region Δλ 2 . Potassium vapor 35 may be selected as the wavelength shifting medium and is diffused in chamber 19 . The vapor can be diffused in chamber 19 by methods well known in the art and elaboration at this point would only belabor the obvious. All the photons in region Δλ 1 have energies between 4.42 and 5.39EV. As these values are larger than the 4.34EV ionization energy of potassium all the UV photons will be absorbed. The fluorescent emission from the potassium vapor consists mainly of the doublets 769.9 and 766.5 nanometer. Appropriately selecting the passband of surface S2 to embrace a passband Δλ 2 extending from 740 nm to 790 nm will transmit the fluorescent emission of the potassium vapor medium for the PMT. A typical photomultiplier tube that can be used is a Hamamatsu Red-Enhanced Multiply-Alkali photocathode type R712. FIG. 3, in its depiction of the energy level diagram of potassium, shows that the major permissible electronic transitions are indicated by vertical lines with the emission wavelengths printed in the center of the line. This type of electronic jump occurs over very narrow energy spread, as the energy levels of the ground state and the excited state are very narrow (assuming the pressure is not too high). Thus, the emission and absorption lines for these states have a very narrow spectral width. On the other hand, the ionized state of the K atom, indicated by the horizontal line at 4.34 is a group of contiguous, continuum states. Thus, the spectral width of this transition will be very broad. One boundary of this width is the minimum energy to ionize the atom, 4.34 e.v., (285.6 nm photons). The other end of this width will extend into the continuum, say to 5 e.v. a photon energy of 248 nm. The ionized atom decays to the ground state by photon emission at 769.9 or 764.5 nm. These two transitions are the strongest in the potassium spectrum. In other words, the K vapor allows a relatively broadband absorption of UV energy over a broad spectral range (about 240 to 280 nm). From this high ionized state, the atoms decay with a subsequent emission at the 769.9 and 766.5 nm, as fluorescent emissions. Inclusion of coating S1 by itself eliminates some spurious impinging energy photons to contribute to more efficient operation. The shifting of the UV radiation by the potassium vapor into the fluorescent spectrum and passing of this spectrum through layer S2 further blocks spurious signals from reaching photomultiplier tube 30 to further avoid creation of erroneous signals. Only the fluorescent radiation which is shifted from the UV spectrum has any effect on the output signal of the photomultiplier tube. Cost effectiveness is assured by substitution of the fluorescent sensitive photomultiplier tube as opposed to a UV spectrum photomultiplier tube. This is because fluorescent sensitive photomultiplier tubes are less complicated to build and, as a consequence, their per unit costs are reduced. Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
An early warning system for detecting the UV from a missile plume has a wide field of view, large spectral bandwidth, solar blind detector. A coated detector passes only a spectral region that embraces UV signals of interest and a wavelength shifter includes a material that shifts the impinging UV energy into a spectrum that embraces the frequencies emitted by fluorescent photons. A photomultiplier tube responsive to the fluorescent emissions provides a responsive read-out indicative of an incoming missile.
Summarize the key points of the given document.
[ "STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.", "BACKGROUND OF THE INVENTION Strike and interceptor aircraft operating in a hostile environment need a wide variety of increasingly sophisticated devices to assure their survival.", "Air or ground launched radar or infrared guided rocket propelled missiles can take a fearsome toll if their presence is not detected soon enough.", "When an early enough detection of these incoming missiles positively can be made, evasive action, flares, electronic counter measures, etc.", "can and greatly do reduce their effectiveness.", "Early warning systems that detect UV from the missile plume require large area, wide field of view detectors.", "In addition to the need for being highly reliable and compact in size it is highly desirable that the detectors be sensitive in the region of the missile plumes+ UV radiation, from 230 to 280 nanometers, to reduce false alarms.", "Contemporary filters that use absorption type materials are expensive since they require large single crystals of nickel sulphate or the like.", "In addition, the solar-blind photomultiplier tubes that have been used with the large crystals also are expensive.", "As a consequence, technology and funding constraints may limit aircraft from having an appropriate detector in some high technology combat zones.", "Thus, a continuing need exists in the state of the art for a large area, wide field of view detector of the UV radiation in a missile plume to assure the timely warning of an incoming missile.", "SUMMARY OF THE INVENTION The present invention is directed to providing a means for detecting the UV radiation of an incoming missile plume.", "A wide field of view detector has a coating that blocks some impinging radiation yet passes the UV radiation of interest that is radiated from an incoming missile plume.", "A material within the detector is stimulated by the incoming UV radiation to shift to fluorescent emissions which are outside the passband of the UV radiation.", "A second coating on an opposite wall of the detector passes the fluorescent emissions to a photomultiplier tube sensitive to the fluorescent emissions.", "A prime object of the invention is to provide an improved detector of UV radiation emanating from a missile plume.", "Another object is to provide a UV radiation detector having a pair of coatings on opposite side of a container filled with a material sensitive to impinging UV radiations to shift to responsive fluorescent emissions.", "Still another object of the invention is to provide for an improved detector of the UV radiation emanating from a missile plume that relies upon less costly photomultiplier tubes sensitive to radiation in the fluorescent spectrum.", "Yet a further object is to provide for an improvement in a UV detector that has a wide area, wide field of view detection capability.", "Still yet another further object is to provide for an apparatus for UV detection that is compact and of reduced cost making it attractive for wide spread application.", "These and other objects of the invention will become more readily apparent from the ensuing specification and appended claims when taken in conjunction with the drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic depiction of the principle constituents of the invention.", "FIG. 2 depicts the passbands of the detector coatings S 1 and S 2 .", "FIG. 3 shows an energy level diagram with electronic transmissions of potassium.", "DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings and in particular FIG. 1, a large area, wide field of view detector apparatus 10 has been designed to detect the UV radiation that is emitted from the missile plume of an incoming missile.", "A hollow container 15 is disposed adjacent to a photomultiplier tube 30 .", "The pillbox-like container is fabricated from a section 16 of a quartz tube that has a pair of quartz plate caps 17 and 18 fused in place to form a cylinder closing a chamber 19 .", "The container has a duct, not shown, to allow introduction of a gas as will be elaborated on below and suitable valves and piping must also be provided to allow the introduction of the gas into chamber 19 .", "An upper surface of cap 17 is provided with a coating S 1 which passes only a spectral region Δλ 1 that lies between λ 1 and λ 2 , see FIG. 2 .", "The transmission characteristic of the material S 1 is depicted as being square in shape.", "This is for purposes of demonstration only, it being realized that a certain amount of curvature is inherent.", "The coating can be a laminate of a first layer which has a low pass characteristic and a second layer which has a high pass characteristic.", "Both of these characteristics are known to be curved, however;", "for purposes of clarification, the passband is depicted as being square with lower and upper limits of 230 nm and 280 nm.", "In other words only solar blind energy can enter into container 15 .", "Coatings having a bandwidth capability as called for above are well within the purview of the current state of the art.", "Numerous laboratories provide such coatings by conventional vapor deposition techniques once the desired passbands are known.", "A typical laboratory having such a capability is the Optical Coating Laboratory Incorporated in Santa Rosa, Calif.", "This laboratory routinely provides such coatings upon request.", "Other laboratories are readily available nation wide to provide similar services.", "An outer surface on cap 18 is provided with a coating S 2 .", "This coating transmits only the wavelength region from λ 3 to λ 4 , a spectral region Δλ 2 .", "This region encompasses all emitted fluorescent photons but does not overlap the passband Δλ 1 .", "Since transmission bands Δλ 1 and Δλ 2 do not overlap, container 15 is completely opaque to all wavelengths incident on it.", "In this case, the bandwidth Δλ 2 may span a range of between 740 nm and 790 nm.", "The coating S 2 like coating S1 is fabricated by a suitably equipped lab in accordance with well established techniques to provide this passband.", "Operation to provide a responsive signal at the output of photomultipler tube 30 requires that there be a wavelength shifting medium within chamber 19 .", "In other words, photons of UV energy passing through coating S1 are shifted to longer wavelengths by the proper medium contained in chamber 19 .", "This wavelength shifting or converting material may be a gas liquid or a solid and should have the following characteristics.", "First it absorbs all the photons that pass through surface S1.", "Second it fluoresces with large values of quantum efficiency with emission of a few wavelengths.", "Third the spectral region Δλ 1 should be removed from the spectral region Δλ 2 for ease of discrimination.", "For this reason coating S2 applied to the surface of cap 18 has a passband Δλ 2 that encompasses all the emitted fluorescent photons of the material contained within chamber 19 .", "Photomultiplier tube 30 behind coating S2 is selected to be sensitive only to the spectral region Δλ 2 .", "Potassium vapor 35 may be selected as the wavelength shifting medium and is diffused in chamber 19 .", "The vapor can be diffused in chamber 19 by methods well known in the art and elaboration at this point would only belabor the obvious.", "All the photons in region Δλ 1 have energies between 4.42 and 5.39EV.", "As these values are larger than the 4.34EV ionization energy of potassium all the UV photons will be absorbed.", "The fluorescent emission from the potassium vapor consists mainly of the doublets 769.9 and 766.5 nanometer.", "Appropriately selecting the passband of surface S2 to embrace a passband Δλ 2 extending from 740 nm to 790 nm will transmit the fluorescent emission of the potassium vapor medium for the PMT.", "A typical photomultiplier tube that can be used is a Hamamatsu Red-Enhanced Multiply-Alkali photocathode type R712.", "FIG. 3, in its depiction of the energy level diagram of potassium, shows that the major permissible electronic transitions are indicated by vertical lines with the emission wavelengths printed in the center of the line.", "This type of electronic jump occurs over very narrow energy spread, as the energy levels of the ground state and the excited state are very narrow (assuming the pressure is not too high).", "Thus, the emission and absorption lines for these states have a very narrow spectral width.", "On the other hand, the ionized state of the K atom, indicated by the horizontal line at 4.34 is a group of contiguous, continuum states.", "Thus, the spectral width of this transition will be very broad.", "One boundary of this width is the minimum energy to ionize the atom, 4.34 e.v., (285.6 nm photons).", "The other end of this width will extend into the continuum, say to 5 e.v. a photon energy of 248 nm.", "The ionized atom decays to the ground state by photon emission at 769.9 or 764.5 nm.", "These two transitions are the strongest in the potassium spectrum.", "In other words, the K vapor allows a relatively broadband absorption of UV energy over a broad spectral range (about 240 to 280 nm).", "From this high ionized state, the atoms decay with a subsequent emission at the 769.9 and 766.5 nm, as fluorescent emissions.", "Inclusion of coating S1 by itself eliminates some spurious impinging energy photons to contribute to more efficient operation.", "The shifting of the UV radiation by the potassium vapor into the fluorescent spectrum and passing of this spectrum through layer S2 further blocks spurious signals from reaching photomultiplier tube 30 to further avoid creation of erroneous signals.", "Only the fluorescent radiation which is shifted from the UV spectrum has any effect on the output signal of the photomultiplier tube.", "Cost effectiveness is assured by substitution of the fluorescent sensitive photomultiplier tube as opposed to a UV spectrum photomultiplier tube.", "This is because fluorescent sensitive photomultiplier tubes are less complicated to build and, as a consequence, their per unit costs are reduced.", "Obviously, many modifications and variations of the present invention are possible in the light of the above teachings.", "It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described." ]
FIELD OF THE INVENTION This invention relates to porous laminated expanded polytetrafluoroethylene. BACKGROUND OF THE INVENTION Porous expanded polytetrafluoroethylene (ePTFE) is a well-known fluoropolymer which is utilized in a wide variety of products. These products include such articles as waterproof rainwear, gaskets, electrical insulation, filters and human implants. Many of these articles and the processes for producing them are described in numerous United States patents. ePTFE articles can be produced in any extrudable shape and as a single or multiple layered article depending on the desired physical properties. Because ePTFE is a thermoset polymer, bonding multiple layers together can be problematic. Various means have been used to laminate PTFE, including pressing the unexpanded extrudate together then expanding the multi-layered article, and by using various thermoplastic and thermoset polymer adhesives to bond expanded PTFE layers together. Most methods for laminating multiple layers with adhesives partially or completely block the pores of the ePTFE, rendering adhesive lamination unsuitable for articles where porosity is a desirable feature. Means for laminating sheets of PTFE to produce a multi-layered microporous article are described in Gore (U.S. Pat. Nos. 3,953,566 and 4,187,390), Hubis (U.S. Pat. Nos. 4,385,093 and 4,478,665) and Kranzler (U.S. Pat. No. 5,641,566). Gore and Hubis teach that layers of PTFE extrudate may be laminated together without using an adhesive. The lamination is achieved by layering PTFE extrudate then bringing the layers into intimate contact by means of pressure. The extrudate is then expanded and sintered to form a porous multi layered article. Although high Z directional strengths as measured in the laboratory can be attained by making laminated ePTFE articles according to these teachings, these laminates are known to delaminate in use. A thermoplastic fluoropolymer, fluorinated ethylene propylene (FEP) is known in the art as a suitable agent for laminating layers of PTFE. For example, facial implants comprising ePFTE sheets laminated with sheets of FEP can be found in the medical marketplace. Implants laminated in this fashion are not known to delaminate in use, however, articles produced by this method are known to be non-porous and hence unsuitable for applications where porosity is a desirable. SUMMARY OF THE INVENTION The present invention is a porous composite comprising two or more layers of ePTFE sheet laminated with a with an expanded thermoplastic. The components of PTFE tape and FEP film are layered together, brought into close contact, then expanded simultaneously in one simple step. The inventive article is low density, soft, and very porous. DETAILED DESCRIPTION OF THE INVENTION The inventive article is a porous multi-layered composite sheet material comprising two or more layers of ePTFE laminated with an expanded thermoplastic film. It is often desirable to sinter the inventive article above the crystalline melt point of PTFE, and many thermoplastic adhesives degrade at sintering temperatures. Thus, in a preferred embodiment the thermoplastic film is a fluoropolymer such as FEP, or an alternative thermoplastic that can withstand temperatures up to about 400 degrees C. A preferred embodiment is a FEP laminated sheet material. This article is produced by alternately layering sheets of PTFE extrudate with thin films of FEP. The PTFE extrudate/FEP layers are brought into close contact by calendering. This composite is then expanded above the melting point of the FEP and below the crystalline melt point of the PTFE. The expanded product may be sintered above the crystalline melt point of the PTFE. The resulting ePTFE/expanded FEP (eFEP) composite article is, non reactive, low in density and soft or compliant making it an excellent biomaterial. Alternatively, substituting calendering with a step wherein the PTFE/FEP layers were subjected to pressure by any other means, such as a press or die would produce a similar article. The important feature of this process is that the layers of the PTFE/FEP layered material are brought into close contact. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a drawing of a preferred embodiment of the invention showing the alternately layering sheets of ePTFE sheet with a thin film of eFEP. DETAILED DESCRIPTION OF THE FIGURES A three dimensional drawing of a preferred embodiment of the invention is shown in FIG. 1 . The layer of eFEP 1 is shown between the layers of ePTFE sheets 2 . Due to the expanded nature of both the ePTFE and eFEP, the layered assembly is porous. EXAMPLE 1 PTFE extrudate tape 0.020 inches thick was made and cut into 6×6 inch squares. 10 PTFE extrudate sheets were layered alternately with a sheet of FEP 0.0005 inches thick between each PTFE extrudate sheet. The layered FEP/PTFE extrudate sheets were calendered to a final thickness of about 0.10 inches. The layered composite was multi-axially expanded at a temperature above the melt point of the FEP and below the crystalline melt point of the PTFE. This ePTFE/eFEP composite sheet was then sintered above the crystalline melt point of PTFE. The material was tested according to standard ASTM methods and the results are shown in TABLE 1. TABLE 1 TENSILE MATRIX MATERIAL STRENGTH TENSILE DENSITY Preferred ˜13 Kg/cm ˜95 Kg/cm ˜0.3 gm/cc Invention The nature of the present invention can be seen in the test data. The density of the present invention is very low at 0.3 gm/cc showing that the material is about 85% porous. The low density of the preferred invention is contributed to by a high porosity This high porosity, in turn, is physically characterized by a very soft or compliant mechanical property.
A low density highly porous laminate sheet material of expanded polytetrafluoroethylene/expanded thermoplastic. The composite sheet material comprises two or more layers of expanded polytetrafluoroethylene laminated with an expanded thermoplastic. A process to make the invention is disclosed.
Summarize the key points of the given document.
[ "FIELD OF THE INVENTION This invention relates to porous laminated expanded polytetrafluoroethylene.", "BACKGROUND OF THE INVENTION Porous expanded polytetrafluoroethylene (ePTFE) is a well-known fluoropolymer which is utilized in a wide variety of products.", "These products include such articles as waterproof rainwear, gaskets, electrical insulation, filters and human implants.", "Many of these articles and the processes for producing them are described in numerous United States patents.", "ePTFE articles can be produced in any extrudable shape and as a single or multiple layered article depending on the desired physical properties.", "Because ePTFE is a thermoset polymer, bonding multiple layers together can be problematic.", "Various means have been used to laminate PTFE, including pressing the unexpanded extrudate together then expanding the multi-layered article, and by using various thermoplastic and thermoset polymer adhesives to bond expanded PTFE layers together.", "Most methods for laminating multiple layers with adhesives partially or completely block the pores of the ePTFE, rendering adhesive lamination unsuitable for articles where porosity is a desirable feature.", "Means for laminating sheets of PTFE to produce a multi-layered microporous article are described in Gore (U.S. Pat. Nos. 3,953,566 and 4,187,390), Hubis (U.S. Pat. Nos. 4,385,093 and 4,478,665) and Kranzler (U.S. Pat. No. 5,641,566).", "Gore and Hubis teach that layers of PTFE extrudate may be laminated together without using an adhesive.", "The lamination is achieved by layering PTFE extrudate then bringing the layers into intimate contact by means of pressure.", "The extrudate is then expanded and sintered to form a porous multi layered article.", "Although high Z directional strengths as measured in the laboratory can be attained by making laminated ePTFE articles according to these teachings, these laminates are known to delaminate in use.", "A thermoplastic fluoropolymer, fluorinated ethylene propylene (FEP) is known in the art as a suitable agent for laminating layers of PTFE.", "For example, facial implants comprising ePFTE sheets laminated with sheets of FEP can be found in the medical marketplace.", "Implants laminated in this fashion are not known to delaminate in use, however, articles produced by this method are known to be non-porous and hence unsuitable for applications where porosity is a desirable.", "SUMMARY OF THE INVENTION The present invention is a porous composite comprising two or more layers of ePTFE sheet laminated with a with an expanded thermoplastic.", "The components of PTFE tape and FEP film are layered together, brought into close contact, then expanded simultaneously in one simple step.", "The inventive article is low density, soft, and very porous.", "DETAILED DESCRIPTION OF THE INVENTION The inventive article is a porous multi-layered composite sheet material comprising two or more layers of ePTFE laminated with an expanded thermoplastic film.", "It is often desirable to sinter the inventive article above the crystalline melt point of PTFE, and many thermoplastic adhesives degrade at sintering temperatures.", "Thus, in a preferred embodiment the thermoplastic film is a fluoropolymer such as FEP, or an alternative thermoplastic that can withstand temperatures up to about 400 degrees C. A preferred embodiment is a FEP laminated sheet material.", "This article is produced by alternately layering sheets of PTFE extrudate with thin films of FEP.", "The PTFE extrudate/FEP layers are brought into close contact by calendering.", "This composite is then expanded above the melting point of the FEP and below the crystalline melt point of the PTFE.", "The expanded product may be sintered above the crystalline melt point of the PTFE.", "The resulting ePTFE/expanded FEP (eFEP) composite article is, non reactive, low in density and soft or compliant making it an excellent biomaterial.", "Alternatively, substituting calendering with a step wherein the PTFE/FEP layers were subjected to pressure by any other means, such as a press or die would produce a similar article.", "The important feature of this process is that the layers of the PTFE/FEP layered material are brought into close contact.", "BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a drawing of a preferred embodiment of the invention showing the alternately layering sheets of ePTFE sheet with a thin film of eFEP.", "DETAILED DESCRIPTION OF THE FIGURES A three dimensional drawing of a preferred embodiment of the invention is shown in FIG. 1 .", "The layer of eFEP 1 is shown between the layers of ePTFE sheets 2 .", "Due to the expanded nature of both the ePTFE and eFEP, the layered assembly is porous.", "EXAMPLE 1 PTFE extrudate tape 0.020 inches thick was made and cut into 6×6 inch squares.", "10 PTFE extrudate sheets were layered alternately with a sheet of FEP 0.0005 inches thick between each PTFE extrudate sheet.", "The layered FEP/PTFE extrudate sheets were calendered to a final thickness of about 0.10 inches.", "The layered composite was multi-axially expanded at a temperature above the melt point of the FEP and below the crystalline melt point of the PTFE.", "This ePTFE/eFEP composite sheet was then sintered above the crystalline melt point of PTFE.", "The material was tested according to standard ASTM methods and the results are shown in TABLE 1.", "TABLE 1 TENSILE MATRIX MATERIAL STRENGTH TENSILE DENSITY Preferred ˜13 Kg/cm ˜95 Kg/cm ˜0.3 gm/cc Invention The nature of the present invention can be seen in the test data.", "The density of the present invention is very low at 0.3 gm/cc showing that the material is about 85% porous.", "The low density of the preferred invention is contributed to by a high porosity This high porosity, in turn, is physically characterized by a very soft or compliant mechanical property." ]
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The subject invention generally pertains to industrial doors having a pliable door curtain, and more specifically to a system responsive to a door impact. [0003] 2. Description of Related Art [0004] Industrial doors in which the door itself is made of pliable material such as fabric are used in a variety of applications, typically for the purpose of separating areas within a building, or closing off building doorways that lead outside. Examples of such pliable doors are planar doors, overhead-storing doors, concertina doors and roll-up doors. Planar doors include frame members on which the fabric comprising the door is disposed. This plane of material is then movable between a doorway blocking position and a storage position, wherein the plane of material and associated frame members are disposed above the doorway. The Same typically includes extensions extending past either side of the door, and which are receivable within guide tracks to guide the door through its vertical movement. These extensions may include wheels or trolleys. An overhead-storing door is similar in that the fabric door is maintained on frame members and is movable between doorway blocking and storage positions. In this door, however, the storage position is overhead, as in a typical garage door. Accordingly, the guide members associated with such a door will curve between the vertical and horizontal. A concertina door includes a fabric panel supported by spaced-apart ribs or stays that are guided for movement along a track. As the ribs travel along the track, the fabric panel folds and unfolds between the ribs to respectively open and close the door. A typical roll-up door comprises a roll-up panel or fabric curtain that is wound about a roller journalled for rotation above the doorway. To close the door, the roller pays out the curtain as two vertical tracks disposed along either side edge of the doorway guide the side edges of the curtain generally along a vertical plane across the doorway. The rotation of the roller is reversed to open the door. Roll-up doors are typically either powered open and closed, or are powered open and allowed to fall closed by gravity. As the invention herein is envisioned for use primarily with roll-up doors, it will be described it reference thereto. However, the invention may also be used in combination with other such pliable industrial doors. [0005] Some roll-up doors have a rigid leading edge provided by a rigid or semi-rigid bar disposed along a lower portion of the curtain. The rigidity of the bar helps keep the curtain within the side tracks and helps the curtain resist wind and other air pressure differentials that may develop across opposite sides of the door. [0006] Other roll-up doors, however, have a curtain with a relatively soft leading edge, To help keep such a curtain within its guide tracks, as well as keep the curtain taut and square to the doorway, opposite ends of the bottom portion of the curtain can be held in tension by two opposing carriages or trolleys that are constrained to travel along the tracks: one in each track. However, the door's lower leading edge does not necessarily have to be held in tension, especially when the door is not subject to significant pressure differentials. [0007] Industrial doors are commonly installed in warehouses, where the doors are very susceptible to being struck by forklifts or other vehicles. To protect the door and the vehicle from damage and to protect personnel in the vicinity of the collision from injury, often some type of breakaway or compliant feature is added to the door. For a door having a rigid reinforcing bar along its leading edge, the bar may be provided with sufficient flexibility and resilience to safely pop out of its track when struck. Alternatively, a hard edge door may have its bottom bar connected at either end to carriages engageable with the tracks such that the bottom bar breaks away from the carriages for an impact. Doors having a relatively soft leading edge may have sufficient flexibility to absorb an impact, or a bottom portion of the door's curtain can be coupled to its two guide carriages by way of a breakaway coupling. The coupling releases the curtain from the carriage upon being subjected to a predetermined breakaway force, thereby limiting the impact force to a predetermined safe level. More information on breakaway couplings can be found in U.S. Pat. No. 5,638,883, which is specifically incorporated by reference herein. [0008] A collision can also occur when a door accidentally closes upon an obstacle in its path, such as an object or a person. To protect the door and obstacle from damage or injury, often some type of switch is installed generally along the lower portion of the door to detect when an obstacle has been encountered. An example of such a switch would be an elongated bumper switch, tape-switch or some other elongated switch extending along the lower, leading edge of the roll-up panel. In reaction to sensing the obstacle upon impact, a set of electrical contacts of the switch typically close to stop or reverse the motor that drives the roller. [0009] However, such switches are impractical for use on a door having a relatively soft leading edge, because the normal flexing of the door curtain could trip the switch prematurely. This can happen regardless of whether the soft leading edge of the curtain is held taut or left relatively loose. Therefore, some doors with a soft leading edge instead include a switch with normally closed contacts that are held open by the tension in the leading edge of the curtain. When an impact forces the leading edge of the curtain to break away from its guide tracks, the resulting release of tension within the curtain allows the switch's contacts to close. The closed contacts provide a signal that can be conveyed to the door's control circuit or an alarm circuit by way of a wire or battery powered radio transmission. Alternatively, a sensing mechanism may be associated with the guide carriages or trolleys associated with the soft edge. This sensing mechanism has a first state when the breakaway connection to the leading edge is intact, and a second state upon breakaway. This change to this second state is detected to stop or reverse the door. [0010] In hard edged doors with a tape switch or other elongated switch, such elongated switches are typically inserted into a sheath attached to the curtain or incorporated within the curtain itself to allow a more durable or suitable sealing member to be installed just below the switch. This allows the very bottom or leading edge of the roll-up panel to be provided with a more compliant sealing material that can effectively conform to seal against the floor beneath the doorway when the door is closed. However, installing switches in such a manner, makes them rather inaccessible for servicing. Serviceability is particularly important, as the switch itself, being disposed along the lower portion of the roll-up panel, places the switch's electrical contacts and other electrical parts in a vulnerable position where they are subject to repeated impacts that could eventually damage the switch. [0011] Further, when such a switch is used on a door having a breakaway coupling, wiring connecting the switch to a terminal associated with the motor's control needs to accommodate the separation of the coupling. That is often accomplished by running a separate coiled wire (i.e., multi-conductor cable) along the outside of the track and extending the wire from the terminal to the switch. Such a wire is usually coiled so it can stretch to accommodate the up and down motion of the door panel as well as the motion of the panel upon breaking away from its carriage. However, an exposed coiled wire can be unsightly, especially when it becomes permanently stretched out from use and begins to sag. As the wire sags, it becomes prone to snagging adjacent parts of the door or other items nearby. SUMMARY OF THE INVENTION [0012] In order to more effectively synthesize a safety switch with a breakaway coupling of a roll-up door, there is provided a breakaway coupling that includes at least one electrical contact that remains coupled to a guide carriage of the door even after the coupling disengages the door's roll-up panel from the carriage. [0013] This eliminates the need for externally running a separate coiled or otherwise flexible wire out to the roll-up panel. [0014] It also positions the electrical contacts of the switch at a more serviceable location and at a location that is beyond the impact-vulnerable central portion of the roll-up panel's leading edge. [0015] In some embodiments, the electrical contacts of the switch are an integral part of the breakaway coupling itself, which is relatively more rugged than small delicate electrical contacts of a conventional electrical switch. [0016] By integrating a safety switch with an omni-directional breakaway coupling, the switch also becomes omni-directional in that it is responsive to an impact from any direction. [0017] There is also provided an impact detection system wherein the sensing circuit includes a conductor that extends across the width of the doorway. For normal door operation, the conductor conducts electricity as part of the sensing circuit. For an impact, however, the conductor is no longer a conductive part of the circuit. This change can be detected and interpreted as an impact having occurred. [0018] There is also provided a breakaway coupling wherein a member associated with a door guide track (e.g., a trolley or guide carriage) and a conductor are in electrical, conductive contact for normal door operation, and are not in conductive contact for a breakaway condition. BRIEF DESCRIPTION OF THE DRAWINGS [0019] [0019]FIG. 1 is a front view of one embodiment with a cut-away portion showing a breakaway coupling. [0020] [0020]FIG. 2 is a cross-sectional top view taken along line 2 - 2 of FIG. 1, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0021] [0021]FIG. 3 is the same view as FIG. 1, but with one of the breakaway couplings disengaged. [0022] [0022]FIG. 4 is a cross-sectional top view taken along line 4 - 4 of FIG. 3, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0023] [0023]FIG. 5 is a front view of another embodiment with a cut-away portion showing a breakaway coupling. [0024] [0024]FIG. 6 is a cross-sectional top view taken along line 6 - 6 of FIG. 5, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0025] [0025]FIG. 7 is the same view as FIG. 5, but with one of the breakaway couplings disengaged. [0026] [0026]FIG. 8 is a cross-sectional top view taken along line 8 - 8 of FIG. 7, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0027] [0027]FIG. 9 is a front view of another embodiment with a cut-away portion showing a breakaway coupling. [0028] [0028]FIG. 10 is a cross-sectional top view taken along line 10 - 10 of FIG. 9, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0029] [0029]FIG. 11 is the same view as FIG. 9, but with both of the breakaway couplings disengaged. [0030] [0030]FIG. 12 is a cross-sectional top view taken along line 12 - 12 of FIG. 11, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0031] [0031]FIG. 13 is a front view of another embodiment with a cut-away portion showing a breakaway coupling. [0032] [0032]FIG. 14 is a cross-sectional top view taken along line 14 - 14 of FIG. 13, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0033] [0033]FIG. 15 is the same view as FIG. 13, but with one of the breakaway couplings disengaged. [0034] [0034]FIG. 16 is a cross-sectional top view taken along line 16 - 16 of FIG. 15, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0035] [0035]FIG. 17 is a front view of another embodiment with a cut-away portion showing a breakaway coupling. [0036] [0036]FIG. 18 is a cross-sectional top view taken along line 18 - 18 of FIG. 17, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0037] [0037]FIG. 19 is the same view as FIG. 17, but with one of the breakaway couplings disengaged. [0038] [0038]FIG. 20 is a cross-sectional top view taken along line 20 - 20 of FIG. 19, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0039] [0039]FIG. 21 is a front view of another embodiment with a cut-away portion showing a breakaway coupling. [0040] [0040]FIG. 22 is a cross-sectional top view taken along line 22 - 22 of FIG. 21, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. [0041] [0041]FIG. 23 is the same view as FIG. 21, but with one of the breakaway couplings disengaged. [0042] [0042]FIG. 24 is a cross-sectional top view taken along line 24 - 24 of FIG. 23, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity. DESCRIPTION OF THE PREFERRED EMBODIMENT [0043] To provide a more durable and readily accessible elongated switch for use along a lower portion of a roll-up door panel releasably held by a breakaway coupling, the embodiment of FIGS. 1 - 4 detects electrical continuity through the coupling itself. Referring to FIG. 1, a roll-up door 10 includes a pair of vertically extending members such as vertical side frames 12 that supports a roller 14 upon which a flexible roll-up panel, such as a fabric curtain 16 , is wound and unwound to respectively open and close the door. In this example, a motor drive unit 18 drives roller 14 to feed panel 16 up and down as vertical slits 20 in frame 12 guide side edges 22 of curtain 16 generally along a vertical plane across the doorway. A lower portion 24 of curtain 16 includes a compliant sealing member 26 at the very bottom or leading edge 28 of the curtain to ensure that the cur seals against the floor when door 10 is closed. [0044] To help keep curtain 16 within slits 20 , as well as help keep curtain 16 taut and square to the doorway under normal operation, and yet still release curtain 16 in the event of a collision, two breakaway couplings 32 releasably couple opposite ends 34 and 36 of lower portion 24 to two opposing carriages 38 or trolleys. In its broadest sense, only one breakaway coupling 32 is needed, but two is preferred. In some embodiments, curtain 16 is kept relatively taut by couplings 32 pulling an elongated member 56 , such as a steel cable, in tension. Other examples of elongated member 56 include, but are not limited to. a fabric strap or an integral fabric portion of curtain 16 itself. However, it should be noted that if desired, the leading edge of curtain 16 could be left relatively loose by not applying tension to member 56 . In such a case, member 56 would first be forced into tension by exertion of an external force upon the door as could by created by a collision. [0045] To protect a door in the event of a collision, a breakaway feature can be provided by a variety of structures. For example, in this exemplary embodiment, breakaway couplings 32 are attached to first members such as carriages 38 that include rollers 40 attached to a bracket 42 . Rollers 40 and bracket 42 conform to the shape of frame 12 (see FIG. 2) to constrain carriage 38 to travel along tracks 44 , as door 10 opens and closes. In this example, tracks 44 are provided by the contour of frames 12 . Each breakaway coupling 32 includes an inner coupling member 46 that releasably engages an outer coupling member 48 to provide a breakaway connection therebetween. Under normal door operation, couplings 32 remain intact, i.e., their coupling members 46 and 48 remain connected to each other and move together. However, in the event of a collision creating a force sufficient to disconnect either breakaway coupling 32 , allowing independent relative movement between the members, the resulting separation of coupling members 46 and 48 protects the rest of the door (especially curtains 16 ) from damage. A disconnectable coupling or breakaway connection can be provided by any one of a wide variety of available mechanisms including, but not limited to, various fittings that mechanically snap together and apart. However, in some preferred embodiments, the disconnectable joint is provided by magnetic attraction between coupling members 46 and 48 . Of course, breakaway couplings may also be provided between trolleys and the rigid bars associated with hard edge doors. The teachings herein are intended to apply to such hard edge doors as well as the soft edge doors specifically described. [0046] In this example, each outer coupling member 48 includes a magnet 50 , while each inner coupling member 46 is of a material that is attracted to magnet 50 (e.g., a ferromagnetic material, such as iron or an iron alloy). Magnet 50 is pivotally connected to bracket 42 by way of a hinge 52 that includes a torsional spring 54 that biases the position of magnet 50 generally away from the center of the doorway and towards side frame 12 . A similar arrangement is provided at both the right and left side of the doorway. Elongated member 56 connects the two inner coupling members 46 to each other. In this example, the elongated member is a conductor in the form of an electrically conductive steel cable 56 that runs through an elongated aperture 58 extending horizontally across curtain 16 . [0047] Under normal operation, cable 56 is kept taut across the width of the doorway by a face 60 of each inner coupling member 46 being magnetically clamped to the magnet 50 of its respective outer coupling member 48 . However, when a collision occurs (i.e., the door strikes an obstacle or something strikes the door) that deflects cable 56 with sufficient force to overcome the magnetic attraction of either breakaway coupling 32 , the two halves of the coupling will separate, as shown near the left side of FIGS. 3 and 4. Note that outer coupling member 48 being restained by side frame 12 enhances this action. When this occurs, usually part of the curt pulls out of slit 20 as well Also, for the magnet 50 that breaks away, the spring loaded hinge 52 urges the magnet to swing back and magnetically cling to the side of frame 12 , which prevents the disengaged trolley 38 from slamming to the floor. Further details of the construction, operation and various alternate embodiments of a magnetic breakaway coupling are disclosed in U.S. Pat. No. 5,638,883, which has already been incorporated by reference herein. [0048] As outer coupling member 48 alternately engages and separates from inner coupling member 46 , their mating surfaces, 62 and 60 , respectively, can serve as electrical contacts of a switch, i.e., a device whose electrical conductivity changes in response to an action. The switch can be used to convey or interrupt an electrical signal in reaction to the breakaway coupling separating. The electrical signal, in turn, can be used to activate an alarm or inhibit continued normal operation of the door, until the separated coupling and the rest of the door are returned to normal, i.e., each coupling is connected and curtain 16 is properly within slits 20 . For the breakaway system of FIGS. 1 - 4 , disabling the operation of door 10 can be carried out by any one of a variety of circuits. In FIG. 1, for example, an electrical power source 64 (e.g., 24 VAC) delivers current in series through a coil 66 of a relay 68 , a wire 70 , electrically conductive bracket 42 , electrically conductive hinge 52 , the left outer coupling member 48 (being electrically conductive itself), the left inner coupling member 46 (also being electrically conductive and while engaging magnet 50 ), cable 56 (or a conductive wire parallel thereto in the case of a nonconductive elongated member), the right inner coupling member 46 , the right outer coupling member 48 (while engaging the right inner coupling member 46 ), right hinge 52 , right bracket 42 and a wire 76 . Wire 76 leads back to power source 64 to complete a sensing circuit 78 when both breakaway couplings 32 are intact. The completed circuit energizes coil 66 to close relay contacts 80 to be used as desired For example, in some embodiment, relay contacts 80 enable a motor control circuit 82 , such as a conventional reversing motor starter that controls the operation of motor 18 . When either coupling 32 breaks away, its corresponding coupling halves 46 and 48 , which in this example serve as electrical contacts, separate to interrupt the continuity of sensing circuit 78 . When this happens, coil 66 de-energizes to open relay contacts 80 , which in turn disables motor control circuit 82 to stop motor 18 . Stopping motor 18 avoids jamming the door and damaging curt 16 by preventing roller 14 from attempting to forcibly raise or lower a curtain that is uncoupled from one or both of its carriages 38 . However, it should be appreciated by those skilled in the art, that sensing circuit 78 could be independent of the operation of motor control circuit 82 . For example, circuit 78 could be used simply to activate an audible or visual alarm, or increment a counter that indicates how often door 10 has been subjected to an impact that caused it to break away. [0049] The system shown in FIGS. 1 - 4 thus senses the exertion of a force above a predetermined magnitude on the curtain. To achieve this, sensing circuit 78 is included, and a conductor (cable 56 ) forms a part of the circuit and extends across the width of the doorway. For normal door operation when no force above the predetermined magnitude is exerted thereon, the conductor is an electrically conductive part of the sensing circuit. When a force above the curtain magnitude is exerted on the curtain, however, the conductor no longer forms a conductive pan of the circuit. Here, this is due to the fact that the coupling members separate, electrically isolating the conductor from the remainder of the circuit. [0050] For the exemplary embodiment just described, it should be appreciated by those skilled in the art, that the wiring diagram of sensing circuit 78 and motor control 82 are schematically illustrated in FIGS. 1 and 3. Much of the circuit and curtain 16 are omitted in FIGS. 2 and 4 to more clearly show other components of the breakaway system. In FIGS. 1 and 3, a simple loop 84 is shown to depict that wires 70 and 76 flex within a flexible cable carrier (e.g., a Model 06-10-028, of IGUS, Inc. from Providence, R.I.) disposed within frame 12 to follow the vertical movement of carriages 38 along tracks 44 . However, the actual path along which the wires are laid; the actual positions of the circuit components; and the actual location of where the wiring connects to the components, including carriage 38 and coupling 32 , can vary widely depending on personal preference and design details of the specific roll-up door to which the breakaway system is applied. In some embodiments, for example, cable 56 can be replaced by a non-conductive fabric strap with an electrical wire connected parallel thereto that electrically couples the two inner coupling members to each other. [0051] In some embodiments, some components such as bracket 42 and hinge 52 are relied upon as electrical conductors in lieu of wires or jumpers, such as optional redundant jumper wires 72 and 74 . However, when doing so, some precautions need to be taken. For example, when bracket 42 is relied upon as an electrical conductor to complete sensing circuit 78 , bracket 42 should be electrically insulated from side frame 12 . This can be done by maintaining an air gap 86 between bracket 42 and frame 12 as shown in FIGS. 2 and 4, or by using various electrically resistive plastic bearing pads and rollers to keep the conductive parts of bracket 42 from contacting frame 12 (i.e., shorting out). Jumper wires 72 and 74 are shown as optional conductors to complete circuit 78 in an embodiment where bracket 42 and hinge 52 are not relied upon to conduct electrical current. [0052] If desired, a circuit breaker or resettable fuse (e.g., a Model MF-R020, of Bourns, Inc. of Riverside Calif.) can be used to protect circuit 78 in the event of an electrical short or current overload. This is particularly important, as magnet 50 short circuits circuit 78 to a grounded frame 12 whenever coupling 32 associated with the magnet breaks away. It should be further noted that while the conductor in this embodiment, which extends across the width of the doorway and selectively either forms or does not form a conductive part of the sensing circuit, is carried on the door curtain, this need not be so. Rather, the conductor could extend across the width of the doorway at other locations and still perform its conducting/non-conducting function. [0053] The embodiment of FIGS. 5 - 8 is similar to the one just described, however, cable 56 is replaced by a two-conductor cable 88 . And each breakaway coupling 90 and 92 has two sets of electrical contacts for a total of eight contacts 94 a - h with contacts 94 d and 94 e sharing a common node at magnet 50 . Contacts 94 a and 94 h are respectively provided by separate magnets 96 and 98 that are electrically conductive, but are insulated from hinge 52 and carriage 38 by way of a nonconductive shim 100 . Each inner coupling member 108 and 112 includes an electrically nonconductive core 101 that electrically separates its respective contacts 94 b and 94 g (coupling member 108 ) and contacts 94 c and 94 f (coupling member 112 ). This arrangement allows wires 102 and 104 to share a common cable carrier disposed inside just one side frame 12 (e.g., the left or right side of the doorway). [0054] Referring to FIG. 5, under normal door operation, power source 64 delivers current in series through coil 66 , wire 104 , magnet 96 , a first contact 94 a of a left outer coupling member 106 , a second contact 94 b of a left inner coupling member 108 , a first wire 110 of cable 88 , a third contact 94 c of a right inner coupling member 112 , a fourth contact 94 d of a right outer coupling member 114 , magnet 50 , a fifth contact 94 e, a sixth contact 94 f, a second wire 116 of cable 98 , a seventh contact 94 g of left inner coupling member 108 , magnet 98 , and wire 102 . Wire 102 leads back to power source 64 to complete a sensing circuit 119 when both breakaway couplings 90 and 92 are intact. The completed circuit energies coil 66 to close relay contacts 80 , which enable the operation of motor 18 to open or close the door. [0055] When either coupling 90 or 92 breaks away in reaction to a collision, its corresponding coupling halves separate to interrupt the continuity of sensing circuit 119 . If coupling 92 on the right breaks away, as shown in FIGS. 7 and 8, contact 94 c and 94 f separate from the combined contacts 94 d and 94 e that are disposed on the face of magnet 50 . If coupling 90 on the left breaks away, contacts 94 a and 94 b separate, and so do contacts 94 g and 94 h. If either coupling 90 or 92 separates, the continuity of circuit 119 is interrupted to disable the operation of motor 82 , thus stopping the opening or closing of the door. The door is reset to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of each breakaway coupling 90 and 92 that may have separated. [0056] Although inner coupling halves 108 and 112 are shown connected to each other by cable 88 , in some embodiments, another elongated member such as a fabric strap or an integral portion of the door curtain itself extends across the width of curtain 16 and generally parallel to cable 88 to hold the two halves 108 and 112 together, which thus relieves the tension in wires 110 and 116 of cable 88 . [0057] In a similar embodiment, shown in FIGS. 9 - 12 , contacts 94 c,d,e,f of FIGS. 5 and 7 are replaced by an electrical switch 118 . Switch 118 is disposed on a right inner coupling member 120 of a breakaway coupling 122 and includes normally open contacts 124 and 126 that are held closed during normal operation of the door. Magnet 50 of outer coupling member 114 at the right side of the door magnetically clings to ferromagnetic blocks 128 that are on inner coupling member 120 . As magnet 50 magnetically clamps against blocks 128 , magnet 50 also depresses a switch actuator 130 that closes contacts 124 and 126 of switch 118 . When closed, contacts 124 and 126 provide electrical continuity between wires 110 and 116 . That continuity was previously provided by contacts 94 c, d, e, f of the embodiment of FIGS. 5 - 8 . When coupling 122 breaks away, as shown in FIGS. 11 and 12, actuator 130 returns to its normally extended position to open contacts 124 and 126 (i.e., break their continuity). This interrupts the current to relay 68 to activate an alarm, or disable motor 18 to stop the door. [0058] The left breakaway coupling 90 of FIGS. 9 - 12 is the same as the one in the embodiment of FIGS. 5 - 8 . It might also be noted that in FIGS. 11 and 12, both breakaway couplings 90 and 122 are shown in their uncoupled state, as this could actually occur in some collisions. [0059] In some applications, it might be beneficial to eliminate the need to extend an electrical conductor across the width of the door curtain. This is accomplished in the embodiment of FIGS. 13 - 16 , wherein both breakaway couplings 131 are basically the same, and their outer coupling halves 106 are the same as the left outer one of FIGS. 9 - 12 . Each outer coupling member 106 includes a pair of spaced-apart magnets 96 and 98 that are electrically insulated from the rest of the coupling member by way of electrically nonconductive shim 100 between hinge 52 and magnets 96 and 98 . Each pair of magnets 96 and 98 provide a corresponding pair of electrical contacts: 132 and 134 on the left and 136 and 138 on the right. Each pair of contacts are shorted out (i.e., electrically connected to each other) by an inner coupling member 46 , which is the same as those used in the embodiment of FIGS. 1 - 4 . However, the two inner coupling halves 46 are connected to each other by an elongated member 140 that does not need to be electrically conductive, such as for example, a cable, strap, or an integral portion of the door curtain itself. [0060] During normal door operation, power supply 64 delivers current in series through relay 68 , wire 104 , contacts 132 , left inner coupling member 46 , contacts 114 , a second wire 142 that leads up and over to the right breakaway coupling 131 , contacts 138 , right inner coupling member 46 , contacts 136 and wire 144 . Wire 144 leads back to power supply 64 to complete a sensing circuit 147 that energizes relay 68 to enable motor 18 to open or close the door. [0061] When either of couplings 131 are forced to break away, the separation of an inner coupling member 46 from its corresponding outer coupling member 106 opens contact, 132 and 134 or 136 and 138 , accordingly. In the example shown in FIGS. 15 and 16, the left breakaway coupling 131 separates to interrupt the continuity of circuit 147 , which de-energizes relay 68 to disable the normal operation of the door. The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 131 . [0062] Another breakaway system that eliminates the need for extending an electrical conductor across the width of the door curtain is shown in FIGS. 17 - 20 . In this example, switch 118 (described earlier in reference to FIGS. 9 - 12 ) is attached to each outer coupling member 148 of breakaway couplings 150 . Each switch 118 is disposed within or adjacent a magnet 152 with the switch's actuator 130 depressed by an inner coupling member 146 that is magnetically drawn up against magnet 152 , as shown in FIGS. 17 and 18 . The two inner coupling halves 146 are connected to each other by elongated member 140 that does not need to be electrically conductive, such as for example, a cable, strap, or an integral portion of the door curtain itself. [0063] During normal operation of the door, current from power supply 64 passes in series through relay 68 , a wire 154 , closed contacts 124 and 126 on the left breakaway coupling, a wire 156 , closed contacts 124 and 126 on the right breakaway coupling, and back to power supply 64 through a wire 158 to complete the continuity of a sensing circuit 160 . This energizes relay 68 to enable motor 18 to open or close the door. [0064] When either of couplings 159 are forced to break away, the separation of an inner coupling member 146 from its corresponding outer coupling member 148 allows the switch actuator 130 associated with the separated coupling to open its contacts 124 and 126 . In the example shown in FIGS. 19 and 20, the left breakaway coupling 150 separates to interrupt the continuity of circuit 160 , which de-energizes relay 68 to disable the normal operation of the door. The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 150 . [0065] FIGS. 21 - 24 illustrate another embodiment of a breakaway system that is very similar to the embodiment of FIG. 17- 20 . However, instead of switches 118 with normally open contacts held closed, the breakaway system employs switches 162 that have normally closed contacts. One switch 162 on a left breakaway coupling 164 has contacts 166 and 168 , and another switch 162 on the right breakaway coupling 164 has contacts 170 and 172 . Each breakaway coupling includes a magnet 174 on an outer coupling member 176 that magnetically clings to inner coupling member 146 . The two inner coupling halves 146 are connected to each other by elongated member 140 that does not need to be electrically conductive, such as the examples mentioned earlier. [0066] During normal operation of the door, current from power supply 64 passes in series through relay 68 , a wire 178 , normally closed contacts 166 and 168 on the left breakaway coupling, a wire 180 , normally closed contacts 170 and 172 on the right breakaway coupling, and back to power supply 64 through a wire 182 to complete the continuity of a sensing circuit 184 . This energizes relay 68 to enable motor 18 to open or close the door. [0067] When a coupling 164 breaks away, for example, the left breakaway coupling 164 of FIGS. 23 and 24, the coupling's spring-loaded hinge 52 swings its magnet 174 and its adjacent switch 162 up against the side of frame 12 . The side of frame 12 depresses the switch's actuator 130 to open contacts 166 and 168 , which interrupts the continuity of circuit 184 . This, in turn, de-energizes relay 68 to disable the normal operation of the door. Although frame 12 is the structure that actuates switch 162 as hinge 52 moves the switch, the actuation could be carried out by a variety of other structures in the vicinity, including but not limited to the hinge itself. The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 164 . [0068] Although the invention is described with respect to preferred embodiments, modifications thereto will be apparent to those skilled in the art. For example, in providing a breakaway coupling that includes two coupling halves that are magnetically attracted to each other, either coupling member could be the magnet with the other coupling member being of a material attracted to the magnet. Also, one coupling member could be an integral component or extension of carriage 38 itself. For instance, it is well within the scope of the invention to eliminate hinge 52 and provide an inner coupling member with a magnet bat clings directly to bracket 42 of carriage 38 . In such a case, the portion of bracket 42 that engages the magnet would serve as the outer coupling member. Since other modifications will be apparent to those skilled in the art, the scope of the invention is to be determined by reference to the claims, which follow.
An impact sensing system for a powered roll-up door combines an electrical switch and a breakaway coupling. To avoid damage or injury resulting from the door's roll-up curtain accidentally closing upon an obstacle or something striking the curtain, the breakaway coupling responds to such a collision by breaking away, which releases a lower portion of the curtain from between its two vertical guide tracks. Each breakaway coupling includes a set of electrical contacts that make or break in response to the coupling breaking away. When the curtain's lower portion becomes effectively derailed from its guide track, the electrical contacts disable continued operation of the door to prevent the door's drive motor from jamming the curtain. In some embodiments, the breakaway coupling is releasably held together by way of magnetic attraction between two coupling segments, with one electrical contact on each segment to comprise one set of functional contacts.
Briefly summarize the main idea's components and working principles as described in the context.
[ "BACKGROUND OF THE INVENTION [0001] 1.", "Field of the Invention [0002] The subject invention generally pertains to industrial doors having a pliable door curtain, and more specifically to a system responsive to a door impact.", "[0003] 2.", "Description of Related Art [0004] Industrial doors in which the door itself is made of pliable material such as fabric are used in a variety of applications, typically for the purpose of separating areas within a building, or closing off building doorways that lead outside.", "Examples of such pliable doors are planar doors, overhead-storing doors, concertina doors and roll-up doors.", "Planar doors include frame members on which the fabric comprising the door is disposed.", "This plane of material is then movable between a doorway blocking position and a storage position, wherein the plane of material and associated frame members are disposed above the doorway.", "The Same typically includes extensions extending past either side of the door, and which are receivable within guide tracks to guide the door through its vertical movement.", "These extensions may include wheels or trolleys.", "An overhead-storing door is similar in that the fabric door is maintained on frame members and is movable between doorway blocking and storage positions.", "In this door, however, the storage position is overhead, as in a typical garage door.", "Accordingly, the guide members associated with such a door will curve between the vertical and horizontal.", "A concertina door includes a fabric panel supported by spaced-apart ribs or stays that are guided for movement along a track.", "As the ribs travel along the track, the fabric panel folds and unfolds between the ribs to respectively open and close the door.", "A typical roll-up door comprises a roll-up panel or fabric curtain that is wound about a roller journalled for rotation above the doorway.", "To close the door, the roller pays out the curtain as two vertical tracks disposed along either side edge of the doorway guide the side edges of the curtain generally along a vertical plane across the doorway.", "The rotation of the roller is reversed to open the door.", "Roll-up doors are typically either powered open and closed, or are powered open and allowed to fall closed by gravity.", "As the invention herein is envisioned for use primarily with roll-up doors, it will be described it reference thereto.", "However, the invention may also be used in combination with other such pliable industrial doors.", "[0005] Some roll-up doors have a rigid leading edge provided by a rigid or semi-rigid bar disposed along a lower portion of the curtain.", "The rigidity of the bar helps keep the curtain within the side tracks and helps the curtain resist wind and other air pressure differentials that may develop across opposite sides of the door.", "[0006] Other roll-up doors, however, have a curtain with a relatively soft leading edge, To help keep such a curtain within its guide tracks, as well as keep the curtain taut and square to the doorway, opposite ends of the bottom portion of the curtain can be held in tension by two opposing carriages or trolleys that are constrained to travel along the tracks: one in each track.", "However, the door's lower leading edge does not necessarily have to be held in tension, especially when the door is not subject to significant pressure differentials.", "[0007] Industrial doors are commonly installed in warehouses, where the doors are very susceptible to being struck by forklifts or other vehicles.", "To protect the door and the vehicle from damage and to protect personnel in the vicinity of the collision from injury, often some type of breakaway or compliant feature is added to the door.", "For a door having a rigid reinforcing bar along its leading edge, the bar may be provided with sufficient flexibility and resilience to safely pop out of its track when struck.", "Alternatively, a hard edge door may have its bottom bar connected at either end to carriages engageable with the tracks such that the bottom bar breaks away from the carriages for an impact.", "Doors having a relatively soft leading edge may have sufficient flexibility to absorb an impact, or a bottom portion of the door's curtain can be coupled to its two guide carriages by way of a breakaway coupling.", "The coupling releases the curtain from the carriage upon being subjected to a predetermined breakaway force, thereby limiting the impact force to a predetermined safe level.", "More information on breakaway couplings can be found in U.S. Pat. No. 5,638,883, which is specifically incorporated by reference herein.", "[0008] A collision can also occur when a door accidentally closes upon an obstacle in its path, such as an object or a person.", "To protect the door and obstacle from damage or injury, often some type of switch is installed generally along the lower portion of the door to detect when an obstacle has been encountered.", "An example of such a switch would be an elongated bumper switch, tape-switch or some other elongated switch extending along the lower, leading edge of the roll-up panel.", "In reaction to sensing the obstacle upon impact, a set of electrical contacts of the switch typically close to stop or reverse the motor that drives the roller.", "[0009] However, such switches are impractical for use on a door having a relatively soft leading edge, because the normal flexing of the door curtain could trip the switch prematurely.", "This can happen regardless of whether the soft leading edge of the curtain is held taut or left relatively loose.", "Therefore, some doors with a soft leading edge instead include a switch with normally closed contacts that are held open by the tension in the leading edge of the curtain.", "When an impact forces the leading edge of the curtain to break away from its guide tracks, the resulting release of tension within the curtain allows the switch's contacts to close.", "The closed contacts provide a signal that can be conveyed to the door's control circuit or an alarm circuit by way of a wire or battery powered radio transmission.", "Alternatively, a sensing mechanism may be associated with the guide carriages or trolleys associated with the soft edge.", "This sensing mechanism has a first state when the breakaway connection to the leading edge is intact, and a second state upon breakaway.", "This change to this second state is detected to stop or reverse the door.", "[0010] In hard edged doors with a tape switch or other elongated switch, such elongated switches are typically inserted into a sheath attached to the curtain or incorporated within the curtain itself to allow a more durable or suitable sealing member to be installed just below the switch.", "This allows the very bottom or leading edge of the roll-up panel to be provided with a more compliant sealing material that can effectively conform to seal against the floor beneath the doorway when the door is closed.", "However, installing switches in such a manner, makes them rather inaccessible for servicing.", "Serviceability is particularly important, as the switch itself, being disposed along the lower portion of the roll-up panel, places the switch's electrical contacts and other electrical parts in a vulnerable position where they are subject to repeated impacts that could eventually damage the switch.", "[0011] Further, when such a switch is used on a door having a breakaway coupling, wiring connecting the switch to a terminal associated with the motor's control needs to accommodate the separation of the coupling.", "That is often accomplished by running a separate coiled wire (i.e., multi-conductor cable) along the outside of the track and extending the wire from the terminal to the switch.", "Such a wire is usually coiled so it can stretch to accommodate the up and down motion of the door panel as well as the motion of the panel upon breaking away from its carriage.", "However, an exposed coiled wire can be unsightly, especially when it becomes permanently stretched out from use and begins to sag.", "As the wire sags, it becomes prone to snagging adjacent parts of the door or other items nearby.", "SUMMARY OF THE INVENTION [0012] In order to more effectively synthesize a safety switch with a breakaway coupling of a roll-up door, there is provided a breakaway coupling that includes at least one electrical contact that remains coupled to a guide carriage of the door even after the coupling disengages the door's roll-up panel from the carriage.", "[0013] This eliminates the need for externally running a separate coiled or otherwise flexible wire out to the roll-up panel.", "[0014] It also positions the electrical contacts of the switch at a more serviceable location and at a location that is beyond the impact-vulnerable central portion of the roll-up panel's leading edge.", "[0015] In some embodiments, the electrical contacts of the switch are an integral part of the breakaway coupling itself, which is relatively more rugged than small delicate electrical contacts of a conventional electrical switch.", "[0016] By integrating a safety switch with an omni-directional breakaway coupling, the switch also becomes omni-directional in that it is responsive to an impact from any direction.", "[0017] There is also provided an impact detection system wherein the sensing circuit includes a conductor that extends across the width of the doorway.", "For normal door operation, the conductor conducts electricity as part of the sensing circuit.", "For an impact, however, the conductor is no longer a conductive part of the circuit.", "This change can be detected and interpreted as an impact having occurred.", "[0018] There is also provided a breakaway coupling wherein a member associated with a door guide track (e.g., a trolley or guide carriage) and a conductor are in electrical, conductive contact for normal door operation, and are not in conductive contact for a breakaway condition.", "BRIEF DESCRIPTION OF THE DRAWINGS [0019] [0019 ]FIG. 1 is a front view of one embodiment with a cut-away portion showing a breakaway coupling.", "[0020] [0020 ]FIG. 2 is a cross-sectional top view taken along line 2 - 2 of FIG. 1, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0021] [0021 ]FIG. 3 is the same view as FIG. 1, but with one of the breakaway couplings disengaged.", "[0022] [0022 ]FIG. 4 is a cross-sectional top view taken along line 4 - 4 of FIG. 3, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0023] [0023 ]FIG. 5 is a front view of another embodiment with a cut-away portion showing a breakaway coupling.", "[0024] [0024 ]FIG. 6 is a cross-sectional top view taken along line 6 - 6 of FIG. 5, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0025] [0025 ]FIG. 7 is the same view as FIG. 5, but with one of the breakaway couplings disengaged.", "[0026] [0026 ]FIG. 8 is a cross-sectional top view taken along line 8 - 8 of FIG. 7, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0027] [0027 ]FIG. 9 is a front view of another embodiment with a cut-away portion showing a breakaway coupling.", "[0028] [0028 ]FIG. 10 is a cross-sectional top view taken along line 10 - 10 of FIG. 9, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0029] [0029 ]FIG. 11 is the same view as FIG. 9, but with both of the breakaway couplings disengaged.", "[0030] [0030 ]FIG. 12 is a cross-sectional top view taken along line 12 - 12 of FIG. 11, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0031] [0031 ]FIG. 13 is a front view of another embodiment with a cut-away portion showing a breakaway coupling.", "[0032] [0032 ]FIG. 14 is a cross-sectional top view taken along line 14 - 14 of FIG. 13, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0033] [0033 ]FIG. 15 is the same view as FIG. 13, but with one of the breakaway couplings disengaged.", "[0034] [0034 ]FIG. 16 is a cross-sectional top view taken along line 16 - 16 of FIG. 15, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0035] [0035 ]FIG. 17 is a front view of another embodiment with a cut-away portion showing a breakaway coupling.", "[0036] [0036 ]FIG. 18 is a cross-sectional top view taken along line 18 - 18 of FIG. 17, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0037] [0037 ]FIG. 19 is the same view as FIG. 17, but with one of the breakaway couplings disengaged.", "[0038] [0038 ]FIG. 20 is a cross-sectional top view taken along line 20 - 20 of FIG. 19, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0039] [0039 ]FIG. 21 is a front view of another embodiment with a cut-away portion showing a breakaway coupling.", "[0040] [0040 ]FIG. 22 is a cross-sectional top view taken along line 22 - 22 of FIG. 21, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "[0041] [0041 ]FIG. 23 is the same view as FIG. 21, but with one of the breakaway couplings disengaged.", "[0042] [0042 ]FIG. 24 is a cross-sectional top view taken along line 24 - 24 of FIG. 23, but with the roll-up panel and wiring leading to the breakaway coupling omitted for clarity.", "DESCRIPTION OF THE PREFERRED EMBODIMENT [0043] To provide a more durable and readily accessible elongated switch for use along a lower portion of a roll-up door panel releasably held by a breakaway coupling, the embodiment of FIGS. 1 - 4 detects electrical continuity through the coupling itself.", "Referring to FIG. 1, a roll-up door 10 includes a pair of vertically extending members such as vertical side frames 12 that supports a roller 14 upon which a flexible roll-up panel, such as a fabric curtain 16 , is wound and unwound to respectively open and close the door.", "In this example, a motor drive unit 18 drives roller 14 to feed panel 16 up and down as vertical slits 20 in frame 12 guide side edges 22 of curtain 16 generally along a vertical plane across the doorway.", "A lower portion 24 of curtain 16 includes a compliant sealing member 26 at the very bottom or leading edge 28 of the curtain to ensure that the cur seals against the floor when door 10 is closed.", "[0044] To help keep curtain 16 within slits 20 , as well as help keep curtain 16 taut and square to the doorway under normal operation, and yet still release curtain 16 in the event of a collision, two breakaway couplings 32 releasably couple opposite ends 34 and 36 of lower portion 24 to two opposing carriages 38 or trolleys.", "In its broadest sense, only one breakaway coupling 32 is needed, but two is preferred.", "In some embodiments, curtain 16 is kept relatively taut by couplings 32 pulling an elongated member 56 , such as a steel cable, in tension.", "Other examples of elongated member 56 include, but are not limited to.", "a fabric strap or an integral fabric portion of curtain 16 itself.", "However, it should be noted that if desired, the leading edge of curtain 16 could be left relatively loose by not applying tension to member 56 .", "In such a case, member 56 would first be forced into tension by exertion of an external force upon the door as could by created by a collision.", "[0045] To protect a door in the event of a collision, a breakaway feature can be provided by a variety of structures.", "For example, in this exemplary embodiment, breakaway couplings 32 are attached to first members such as carriages 38 that include rollers 40 attached to a bracket 42 .", "Rollers 40 and bracket 42 conform to the shape of frame 12 (see FIG. 2) to constrain carriage 38 to travel along tracks 44 , as door 10 opens and closes.", "In this example, tracks 44 are provided by the contour of frames 12 .", "Each breakaway coupling 32 includes an inner coupling member 46 that releasably engages an outer coupling member 48 to provide a breakaway connection therebetween.", "Under normal door operation, couplings 32 remain intact, i.e., their coupling members 46 and 48 remain connected to each other and move together.", "However, in the event of a collision creating a force sufficient to disconnect either breakaway coupling 32 , allowing independent relative movement between the members, the resulting separation of coupling members 46 and 48 protects the rest of the door (especially curtains 16 ) from damage.", "A disconnectable coupling or breakaway connection can be provided by any one of a wide variety of available mechanisms including, but not limited to, various fittings that mechanically snap together and apart.", "However, in some preferred embodiments, the disconnectable joint is provided by magnetic attraction between coupling members 46 and 48 .", "Of course, breakaway couplings may also be provided between trolleys and the rigid bars associated with hard edge doors.", "The teachings herein are intended to apply to such hard edge doors as well as the soft edge doors specifically described.", "[0046] In this example, each outer coupling member 48 includes a magnet 50 , while each inner coupling member 46 is of a material that is attracted to magnet 50 (e.g., a ferromagnetic material, such as iron or an iron alloy).", "Magnet 50 is pivotally connected to bracket 42 by way of a hinge 52 that includes a torsional spring 54 that biases the position of magnet 50 generally away from the center of the doorway and towards side frame 12 .", "A similar arrangement is provided at both the right and left side of the doorway.", "Elongated member 56 connects the two inner coupling members 46 to each other.", "In this example, the elongated member is a conductor in the form of an electrically conductive steel cable 56 that runs through an elongated aperture 58 extending horizontally across curtain 16 .", "[0047] Under normal operation, cable 56 is kept taut across the width of the doorway by a face 60 of each inner coupling member 46 being magnetically clamped to the magnet 50 of its respective outer coupling member 48 .", "However, when a collision occurs (i.e., the door strikes an obstacle or something strikes the door) that deflects cable 56 with sufficient force to overcome the magnetic attraction of either breakaway coupling 32 , the two halves of the coupling will separate, as shown near the left side of FIGS. 3 and 4.", "Note that outer coupling member 48 being restained by side frame 12 enhances this action.", "When this occurs, usually part of the curt pulls out of slit 20 as well Also, for the magnet 50 that breaks away, the spring loaded hinge 52 urges the magnet to swing back and magnetically cling to the side of frame 12 , which prevents the disengaged trolley 38 from slamming to the floor.", "Further details of the construction, operation and various alternate embodiments of a magnetic breakaway coupling are disclosed in U.S. Pat. No. 5,638,883, which has already been incorporated by reference herein.", "[0048] As outer coupling member 48 alternately engages and separates from inner coupling member 46 , their mating surfaces, 62 and 60 , respectively, can serve as electrical contacts of a switch, i.e., a device whose electrical conductivity changes in response to an action.", "The switch can be used to convey or interrupt an electrical signal in reaction to the breakaway coupling separating.", "The electrical signal, in turn, can be used to activate an alarm or inhibit continued normal operation of the door, until the separated coupling and the rest of the door are returned to normal, i.e., each coupling is connected and curtain 16 is properly within slits 20 .", "For the breakaway system of FIGS. 1 - 4 , disabling the operation of door 10 can be carried out by any one of a variety of circuits.", "In FIG. 1, for example, an electrical power source 64 (e.g., 24 VAC) delivers current in series through a coil 66 of a relay 68 , a wire 70 , electrically conductive bracket 42 , electrically conductive hinge 52 , the left outer coupling member 48 (being electrically conductive itself), the left inner coupling member 46 (also being electrically conductive and while engaging magnet 50 ), cable 56 (or a conductive wire parallel thereto in the case of a nonconductive elongated member), the right inner coupling member 46 , the right outer coupling member 48 (while engaging the right inner coupling member 46 ), right hinge 52 , right bracket 42 and a wire 76 .", "Wire 76 leads back to power source 64 to complete a sensing circuit 78 when both breakaway couplings 32 are intact.", "The completed circuit energizes coil 66 to close relay contacts 80 to be used as desired For example, in some embodiment, relay contacts 80 enable a motor control circuit 82 , such as a conventional reversing motor starter that controls the operation of motor 18 .", "When either coupling 32 breaks away, its corresponding coupling halves 46 and 48 , which in this example serve as electrical contacts, separate to interrupt the continuity of sensing circuit 78 .", "When this happens, coil 66 de-energizes to open relay contacts 80 , which in turn disables motor control circuit 82 to stop motor 18 .", "Stopping motor 18 avoids jamming the door and damaging curt 16 by preventing roller 14 from attempting to forcibly raise or lower a curtain that is uncoupled from one or both of its carriages 38 .", "However, it should be appreciated by those skilled in the art, that sensing circuit 78 could be independent of the operation of motor control circuit 82 .", "For example, circuit 78 could be used simply to activate an audible or visual alarm, or increment a counter that indicates how often door 10 has been subjected to an impact that caused it to break away.", "[0049] The system shown in FIGS. 1 - 4 thus senses the exertion of a force above a predetermined magnitude on the curtain.", "To achieve this, sensing circuit 78 is included, and a conductor (cable 56 ) forms a part of the circuit and extends across the width of the doorway.", "For normal door operation when no force above the predetermined magnitude is exerted thereon, the conductor is an electrically conductive part of the sensing circuit.", "When a force above the curtain magnitude is exerted on the curtain, however, the conductor no longer forms a conductive pan of the circuit.", "Here, this is due to the fact that the coupling members separate, electrically isolating the conductor from the remainder of the circuit.", "[0050] For the exemplary embodiment just described, it should be appreciated by those skilled in the art, that the wiring diagram of sensing circuit 78 and motor control 82 are schematically illustrated in FIGS. 1 and 3.", "Much of the circuit and curtain 16 are omitted in FIGS. 2 and 4 to more clearly show other components of the breakaway system.", "In FIGS. 1 and 3, a simple loop 84 is shown to depict that wires 70 and 76 flex within a flexible cable carrier (e.g., a Model 06-10-028, of IGUS, Inc. from Providence, R.I.) disposed within frame 12 to follow the vertical movement of carriages 38 along tracks 44 .", "However, the actual path along which the wires are laid;", "the actual positions of the circuit components;", "and the actual location of where the wiring connects to the components, including carriage 38 and coupling 32 , can vary widely depending on personal preference and design details of the specific roll-up door to which the breakaway system is applied.", "In some embodiments, for example, cable 56 can be replaced by a non-conductive fabric strap with an electrical wire connected parallel thereto that electrically couples the two inner coupling members to each other.", "[0051] In some embodiments, some components such as bracket 42 and hinge 52 are relied upon as electrical conductors in lieu of wires or jumpers, such as optional redundant jumper wires 72 and 74 .", "However, when doing so, some precautions need to be taken.", "For example, when bracket 42 is relied upon as an electrical conductor to complete sensing circuit 78 , bracket 42 should be electrically insulated from side frame 12 .", "This can be done by maintaining an air gap 86 between bracket 42 and frame 12 as shown in FIGS. 2 and 4, or by using various electrically resistive plastic bearing pads and rollers to keep the conductive parts of bracket 42 from contacting frame 12 (i.e., shorting out).", "Jumper wires 72 and 74 are shown as optional conductors to complete circuit 78 in an embodiment where bracket 42 and hinge 52 are not relied upon to conduct electrical current.", "[0052] If desired, a circuit breaker or resettable fuse (e.g., a Model MF-R020, of Bourns, Inc. of Riverside Calif.) can be used to protect circuit 78 in the event of an electrical short or current overload.", "This is particularly important, as magnet 50 short circuits circuit 78 to a grounded frame 12 whenever coupling 32 associated with the magnet breaks away.", "It should be further noted that while the conductor in this embodiment, which extends across the width of the doorway and selectively either forms or does not form a conductive part of the sensing circuit, is carried on the door curtain, this need not be so.", "Rather, the conductor could extend across the width of the doorway at other locations and still perform its conducting/non-conducting function.", "[0053] The embodiment of FIGS. 5 - 8 is similar to the one just described, however, cable 56 is replaced by a two-conductor cable 88 .", "And each breakaway coupling 90 and 92 has two sets of electrical contacts for a total of eight contacts 94 a - h with contacts 94 d and 94 e sharing a common node at magnet 50 .", "Contacts 94 a and 94 h are respectively provided by separate magnets 96 and 98 that are electrically conductive, but are insulated from hinge 52 and carriage 38 by way of a nonconductive shim 100 .", "Each inner coupling member 108 and 112 includes an electrically nonconductive core 101 that electrically separates its respective contacts 94 b and 94 g (coupling member 108 ) and contacts 94 c and 94 f (coupling member 112 ).", "This arrangement allows wires 102 and 104 to share a common cable carrier disposed inside just one side frame 12 (e.g., the left or right side of the doorway).", "[0054] Referring to FIG. 5, under normal door operation, power source 64 delivers current in series through coil 66 , wire 104 , magnet 96 , a first contact 94 a of a left outer coupling member 106 , a second contact 94 b of a left inner coupling member 108 , a first wire 110 of cable 88 , a third contact 94 c of a right inner coupling member 112 , a fourth contact 94 d of a right outer coupling member 114 , magnet 50 , a fifth contact 94 e, a sixth contact 94 f, a second wire 116 of cable 98 , a seventh contact 94 g of left inner coupling member 108 , magnet 98 , and wire 102 .", "Wire 102 leads back to power source 64 to complete a sensing circuit 119 when both breakaway couplings 90 and 92 are intact.", "The completed circuit energies coil 66 to close relay contacts 80 , which enable the operation of motor 18 to open or close the door.", "[0055] When either coupling 90 or 92 breaks away in reaction to a collision, its corresponding coupling halves separate to interrupt the continuity of sensing circuit 119 .", "If coupling 92 on the right breaks away, as shown in FIGS. 7 and 8, contact 94 c and 94 f separate from the combined contacts 94 d and 94 e that are disposed on the face of magnet 50 .", "If coupling 90 on the left breaks away, contacts 94 a and 94 b separate, and so do contacts 94 g and 94 h. If either coupling 90 or 92 separates, the continuity of circuit 119 is interrupted to disable the operation of motor 82 , thus stopping the opening or closing of the door.", "The door is reset to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of each breakaway coupling 90 and 92 that may have separated.", "[0056] Although inner coupling halves 108 and 112 are shown connected to each other by cable 88 , in some embodiments, another elongated member such as a fabric strap or an integral portion of the door curtain itself extends across the width of curtain 16 and generally parallel to cable 88 to hold the two halves 108 and 112 together, which thus relieves the tension in wires 110 and 116 of cable 88 .", "[0057] In a similar embodiment, shown in FIGS. 9 - 12 , contacts 94 c,d,e,f of FIGS. 5 and 7 are replaced by an electrical switch 118 .", "Switch 118 is disposed on a right inner coupling member 120 of a breakaway coupling 122 and includes normally open contacts 124 and 126 that are held closed during normal operation of the door.", "Magnet 50 of outer coupling member 114 at the right side of the door magnetically clings to ferromagnetic blocks 128 that are on inner coupling member 120 .", "As magnet 50 magnetically clamps against blocks 128 , magnet 50 also depresses a switch actuator 130 that closes contacts 124 and 126 of switch 118 .", "When closed, contacts 124 and 126 provide electrical continuity between wires 110 and 116 .", "That continuity was previously provided by contacts 94 c, d, e, f of the embodiment of FIGS. 5 - 8 .", "When coupling 122 breaks away, as shown in FIGS. 11 and 12, actuator 130 returns to its normally extended position to open contacts 124 and 126 (i.e., break their continuity).", "This interrupts the current to relay 68 to activate an alarm, or disable motor 18 to stop the door.", "[0058] The left breakaway coupling 90 of FIGS. 9 - 12 is the same as the one in the embodiment of FIGS. 5 - 8 .", "It might also be noted that in FIGS. 11 and 12, both breakaway couplings 90 and 122 are shown in their uncoupled state, as this could actually occur in some collisions.", "[0059] In some applications, it might be beneficial to eliminate the need to extend an electrical conductor across the width of the door curtain.", "This is accomplished in the embodiment of FIGS. 13 - 16 , wherein both breakaway couplings 131 are basically the same, and their outer coupling halves 106 are the same as the left outer one of FIGS. 9 - 12 .", "Each outer coupling member 106 includes a pair of spaced-apart magnets 96 and 98 that are electrically insulated from the rest of the coupling member by way of electrically nonconductive shim 100 between hinge 52 and magnets 96 and 98 .", "Each pair of magnets 96 and 98 provide a corresponding pair of electrical contacts: 132 and 134 on the left and 136 and 138 on the right.", "Each pair of contacts are shorted out (i.e., electrically connected to each other) by an inner coupling member 46 , which is the same as those used in the embodiment of FIGS. 1 - 4 .", "However, the two inner coupling halves 46 are connected to each other by an elongated member 140 that does not need to be electrically conductive, such as for example, a cable, strap, or an integral portion of the door curtain itself.", "[0060] During normal door operation, power supply 64 delivers current in series through relay 68 , wire 104 , contacts 132 , left inner coupling member 46 , contacts 114 , a second wire 142 that leads up and over to the right breakaway coupling 131 , contacts 138 , right inner coupling member 46 , contacts 136 and wire 144 .", "Wire 144 leads back to power supply 64 to complete a sensing circuit 147 that energizes relay 68 to enable motor 18 to open or close the door.", "[0061] When either of couplings 131 are forced to break away, the separation of an inner coupling member 46 from its corresponding outer coupling member 106 opens contact, 132 and 134 or 136 and 138 , accordingly.", "In the example shown in FIGS. 15 and 16, the left breakaway coupling 131 separates to interrupt the continuity of circuit 147 , which de-energizes relay 68 to disable the normal operation of the door.", "The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 131 .", "[0062] Another breakaway system that eliminates the need for extending an electrical conductor across the width of the door curtain is shown in FIGS. 17 - 20 .", "In this example, switch 118 (described earlier in reference to FIGS. 9 - 12 ) is attached to each outer coupling member 148 of breakaway couplings 150 .", "Each switch 118 is disposed within or adjacent a magnet 152 with the switch's actuator 130 depressed by an inner coupling member 146 that is magnetically drawn up against magnet 152 , as shown in FIGS. 17 and 18 .", "The two inner coupling halves 146 are connected to each other by elongated member 140 that does not need to be electrically conductive, such as for example, a cable, strap, or an integral portion of the door curtain itself.", "[0063] During normal operation of the door, current from power supply 64 passes in series through relay 68 , a wire 154 , closed contacts 124 and 126 on the left breakaway coupling, a wire 156 , closed contacts 124 and 126 on the right breakaway coupling, and back to power supply 64 through a wire 158 to complete the continuity of a sensing circuit 160 .", "This energizes relay 68 to enable motor 18 to open or close the door.", "[0064] When either of couplings 159 are forced to break away, the separation of an inner coupling member 146 from its corresponding outer coupling member 148 allows the switch actuator 130 associated with the separated coupling to open its contacts 124 and 126 .", "In the example shown in FIGS. 19 and 20, the left breakaway coupling 150 separates to interrupt the continuity of circuit 160 , which de-energizes relay 68 to disable the normal operation of the door.", "The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 150 .", "[0065] FIGS. 21 - 24 illustrate another embodiment of a breakaway system that is very similar to the embodiment of FIG. 17- 20 .", "However, instead of switches 118 with normally open contacts held closed, the breakaway system employs switches 162 that have normally closed contacts.", "One switch 162 on a left breakaway coupling 164 has contacts 166 and 168 , and another switch 162 on the right breakaway coupling 164 has contacts 170 and 172 .", "Each breakaway coupling includes a magnet 174 on an outer coupling member 176 that magnetically clings to inner coupling member 146 .", "The two inner coupling halves 146 are connected to each other by elongated member 140 that does not need to be electrically conductive, such as the examples mentioned earlier.", "[0066] During normal operation of the door, current from power supply 64 passes in series through relay 68 , a wire 178 , normally closed contacts 166 and 168 on the left breakaway coupling, a wire 180 , normally closed contacts 170 and 172 on the right breakaway coupling, and back to power supply 64 through a wire 182 to complete the continuity of a sensing circuit 184 .", "This energizes relay 68 to enable motor 18 to open or close the door.", "[0067] When a coupling 164 breaks away, for example, the left breakaway coupling 164 of FIGS. 23 and 24, the coupling's spring-loaded hinge 52 swings its magnet 174 and its adjacent switch 162 up against the side of frame 12 .", "The side of frame 12 depresses the switch's actuator 130 to open contacts 166 and 168 , which interrupts the continuity of circuit 184 .", "This, in turn, de-energizes relay 68 to disable the normal operation of the door.", "Although frame 12 is the structure that actuates switch 162 as hinge 52 moves the switch, the actuation could be carried out by a variety of other structures in the vicinity, including but not limited to the hinge itself.", "The door is returned to normal operation by placing curtain 16 back into slits 20 and reconnecting the two halves of the left breakaway coupling 164 .", "[0068] Although the invention is described with respect to preferred embodiments, modifications thereto will be apparent to those skilled in the art.", "For example, in providing a breakaway coupling that includes two coupling halves that are magnetically attracted to each other, either coupling member could be the magnet with the other coupling member being of a material attracted to the magnet.", "Also, one coupling member could be an integral component or extension of carriage 38 itself.", "For instance, it is well within the scope of the invention to eliminate hinge 52 and provide an inner coupling member with a magnet bat clings directly to bracket 42 of carriage 38 .", "In such a case, the portion of bracket 42 that engages the magnet would serve as the outer coupling member.", "Since other modifications will be apparent to those skilled in the art, the scope of the invention is to be determined by reference to the claims, which follow." ]
BACKGROUND [0001] The present invention generally relates to shoe attachment devices, and it is specifically directed to a device that is attachable to the metatarsal area of a laced shoe so as to assist its wearer in using a leg to pull a loaded hand truck out from underneath a heavy load placed thereupon without subjecting the foot to undue blunt trauma or potentially injurious strain. [0002] Foot injuries not caused by running or jumping are, typically, caused by any one of three things: (a) accidental striking of the metatarsal or toe area of the foot by falling objects; (b) accidental striking of the heel or toe area of the foot against lying or erected objects; or (c) deliberate striking of the metatarsal or toe area of the foot against sporting balls and other objects. Protecting the foot against these typical causes of injury is achieved through either shoe construction or use of an extraneous (to the shoe) protective device. [0003] Shoe designs for protecting against injuries caused by either of the two aforementioned types of accidental foot striking events often feature metal or hard plastic reinforced toe and/or heel portions of the upper, or “vamp,” part of the shoe. In some cases, these protective shoe uppers also have built into them rigid devices that cover the metatarsal area of the foot. One such example is found in U.S. Pat. No. 7,328,526 to Peterson. Peterson discloses a shoe upper having a metatarsal guard formed within it. The guard is a rigidly flexible convex piece that extends from the rear of the wearer's toes to the top of the wearer's instep. Shoes and boots having uppers that are configured to be protective are standard attire for industrial workers, for example. However, because of their rigidity and, typically, their non-breathability, these kinds of footwear are generally preferred for use in the physical labor environment, but not so much for casual wear and certainly not for use in athletic activities in which the risk of the foot impacting anything other than the ground is minimal (e.g., running, weightlifting, etc.). Consequently, the prior art is replete with devices that are removably attachable to shoes for the purpose of protecting users' feet from injuries caused by any of the aforementioned three types of foot striking events. [0004] For example, U.S. Pat. No. 8,959,801 to Siragusa discloses an ankle and foot protector device for attaching to a hockey skate. The Siragusa device is formed by a generally rectangular instep protector pad that covers the length of the instep and a transversely oriented ankle protector pad. Pairs of laterally spaced holes formed in each pad that allow skate laces to be threaded through them, coupled with a strap of hook and loop fastener material, permits the device to be securely mounted to the skate. The two pads are configured to be effective in protecting a wearer's foot from the high impact of a flying hockey puck. However, they, theoretically, could be mounted to a different type of footwear to protect the foot in other contexts. [0005] Nevertheless, despite the ample number of existent foot protection devices that are configured to prevent foot injury caused by any of the three common types of foot impact events described above, that the present inventor is aware, there is no prior art device configured specifically to prevent the type of foot discomfort and injury that might be result from removing loads from a hand truck in a particular manner. [0006] A common type of hand truck, or “dolly,” is a two-wheeled, L-shaped apparatus that features a horizontal, load-supporting platform and axle-mounted wheels, at its lower end, which are connected, by a vertical support structure, to one or two handles situated at its upper end. The purpose of a dolly is to transport boxes and other items that are too heavy or too large to be simply lifted and carried to a destination without enormous physical strain and with much greater efficiency than carrying them by hand. This is accomplished by placing a load to be hauled atop the dolly platform and using the handle(s) to rock the apparatus backward so that the platform and load are rotated off the ground—causing the vertical support structure and the platform to cradlingly support the load while only the wheels are contacting the ground. [0007] Often, with heavier loads, it is helpful for a user to place his or her foot atop the wheel axle in order to gain leverage when rocking the dolly backward to lift its loaded platform. Using the foot in this manner is usually non-problematic because the sole of the shoe dampens the impact between the bottom of the foot and the dolly's steel axle rod. However, the same cannot be said for the foot maneuver that is often employed to remove the load from the dolly platform upon arriving at the drop-off destination at the end of the haul. More specifically, in effort to be more time efficient, if not to simply to avoid the physical arduousness of removing the load item(s) from the dolly platform by hand, one might be inclined to simply pull the dolly such that its ground-resting platform slides out from underneath the still sitting load that has a bottom surface area which extends beyond the surface area of the dolly platform. And since pulling at the vertically higher handle(s) would generate torque that would, initially, cause the platform to vertically lift, rather than horizontally slide, one might use a foot and leg to pull horizontally on the dolly at its lower end. This can be accomplished by placing a foot underneath the wheel axle and lifting the toes upward so that the axle is wedged into the crease formed at the meeting of the front metatarsal area of the foot and the toes—rendering the toes a vertical barrier against the axle in order that leg muscles, rather than upper body muscles, are exerted to deliver the pulling force needed to withdraw the horizontal platform from underneath the heavy load. [0008] For persons in the ground freight and product distribution industries who routinely use dollies to move heavy stacks of boxes and other items and who must work quickly, this leg-pulling technique is often used repeatedly to unload dollies. Unfortunately, the resulting blunt trauma sustained by the more tender top of the foot can cause painful bruising, fatigued foot and calf muscles and even more debilitating injury. However, again, the present inventor is not aware of any shoe-mountable aids for alleviating pressure on the foot and reducing the discomfort and risk of injury caused by this dolly pulling maneuver. More specifically, while many of the prior art protective devices may be configured so as to dampen any impact that might occur between the metatarsal area of the foot and a dolly axle, they are not configured to be able to hook or cradle the axle without the wearer having to curl his toes upward and around the axle in order that toes become a somewhat vertical support that presses against the axle and allows the leg to pull the lower end of the dolly such that the dolly platform may simply be slid out from under its load, rather than be tilted into lifting the load from the ground. [0009] Consequently, the present inventor appreciates a need for a device that: (1) can be easily and securely attached to a laced shoe; (2) enables a user to use his leg to apply pulling force to the wheel axle of a dolly without having to curl his entire foot or toes upward to cradle the axle; and (3) is configured such that it minimizes the likelihood that that leg pulling motion causes discomforting or injurious strain to be placed on the user's foot. The present invention for a shoe-mounted dolly pulling device substantially fulfills these needs. SUMMARY [0010] In order for a dolly operator to separate a large load from a dolly platform by removing the dolly from the load, rather than by removing the load from the dolly, the operator must pull the dolly horizontally toward himself. More specifically, he must pull on the dolly at its lower end and not its upper, handle end. That is because, if the pulling force is applied at the upper end of the dolly, the weight of the load will cause the dolly wheels to act as a fulcrum, and the platform will rotate vertically upward, rather than it sliding horizontally toward the operator's body. Therefore, to avoid the discomfort, upper body strain and potential back injury that might result from crouching and pulling on the lower end of the hand truck with the hands, a dolly operator will typically engage the dolly wheel axle with one of his feet and use that leg to pull the lower end of the dolly toward him—allowing bottom surface area of the load that extends beyond the dolly platform to engage the ground and resist sliding along with the platform due to ground friction. Although a time saving maneuver, repeatedly doing this can greatly strain the delicate toe and foot muscles and the lower leg muscles that must be exerted to keep the axle cradled within the crease formed at the meeting of the front metatarsal and phalangeal regions of the foot and to deliver sufficient pulling force to slide the dolly while the axle presses against the toes. This repeated action can also strain, and potentially rupture, the Achilles tendon, much less cause severe foot bruising and soreness. [0011] Therefore, it is an object of the present invention to provide a device that, when attached to a shoe, is configured to enable its wearer to perform the aforementioned leg pulling technique on a loaded dolly without even utilizing many of the same foot and leg muscles—at least not to any great extent—that would be exerted without the aid of the present device. In one aspect of the invention, the present device is formed by a convexly-shaped metatarsal guard that inserts into a shoe to fit atop the front metatarsal area of the foot and an upward extending lip that resides at the front end of the guard to give the device an L-shaped profile. So, instead of the wearer's foot and toes having to cradle the dolly axle, the device hooks around the axle with the lip forming a vertical structure that presses against the axle when the sole of the foot is held parallel to the ground and the foot is drawn along a horizontal plane away from the load. As a consequence, the user does not have to curl his toes upward or keep any muscles of the metatarsal or toes tensed in order to maintain that foot posture against heavy resistance imposed by the dolly axle. This significantly reduces strain on the foot muscles and Achilles tendon. As another consequence, the greatest resistance force imposed by the dolly axle (due to the weight of the load atop the dolly platform) is applied directly the device lip and not to the top of the foot. [0012] It is another object of the invention to eliminate the foot bruising that currently occurs along the area of contact between the foot and the dolly axle when a dolly operator uses a leg to pull the dolly from underneath a load. In another aspect of the invention, the present device features resilient padding material underneath (on the foot side of) the metatarsal guard and the lip. Therefore, when the device is torqued by its lip being pressed against the axle, resilient material, not the rigid material that forms the metatarsal guard and the device lip nor the metal of the dolly axle, presses against the foot. Because the impact that is applied to the foot is both (1) softened by the padding material and (2) distributed over much, if not all, of the padded undersides of the lip and metatarsal guard (a composite surface area that is significantly broader than is the shoe surface area that would otherwise be in direct contact with the dolly axle), bruising is much less likely to occur than if same maneuver is performed without the present device. [0013] Finally, it is another object of the present invention to be so unencumbering to wearers of casual and athletic shoes that, once installed onto a laced shoe, the user will not feel compelled to ever remove the present device in order to wear the shoe free of the device when not operating a dolly. In other words, the object is for the device to be immaterial to the general functionality and performance of the shoe to which it is attached so as to obviate the need to detach the device or change shoes after dolly use and before engaging in other activities. In another aspect of the invention, present device is lightweight, its metatarsal covering portion is contoured to generally conform to the foot, its lip portion has a fairly low profile and its underside is cushioned. Furthermore, the laterally outer areas of the metatarsal covering portion have apertures formed within them to allow shoe laces to be threaded through the device to securely anchors it to the forward metatarsal area of the shoe without covering the toes or obstructing their movement. Consequently, the present device can remain perpetually installed onto, say, an athletic shoe without appreciably inhibiting any movements or sacrificing any comfort during non-dolly related wear. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a right perspective view of the shoe attachment device in accordance with the present disclosure; [0015] FIG. 2 is another perspective view of the same; and [0016] FIG. 3 is a right perspective view of the same, the device being shown attached to a show and engaging a dolly wheel axle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0017] Referring now to FIGS. 1 and 2 , there is illustrated a preferred embodiment of the shoe attachment device 1 of the present invention. The present device 1 is attachable to a laced shoe 30 , as shown in FIG. 3 , and it enables the user to hook and horizontally pull on the wheel axle 20 of a common hand truck with his or her leg. [0018] Generally speaking, when a load-carrying hand truck, or “dolly,” is sitting upright on the ground, the load that it is used to haul rests on the platform part (not shown) of the dolly while the platform is flush against the ground. Therefore, if the bottom surface area of the load is more expansive than is the surface area of the dolly platform, part of that load bottom surface will be separated from the ground only due the thickness of the dolly platform, and some of it may even be contacting the ground while the dolly is at rest. Of course, if not already contacting the ground, it can be easily put in contact with the ground by the dolly operator slightly tilting the dolly forward. In any event, a portion of the load bottom surface being in contact with the ground allows for friction between those surfaces to produce relative movement of the platform and the load when the dolly is pulled horizontally. More specifically, application of pulling force to the dolly may cause the dolly platform to travel horizontally while ground friction causes load item remain(s) to remain in place such that, eventually, the load is entirely resting upon the ground and the dolly platform is entirely removed from underneath it. The shoe attachment device 1 of the present invention facilitates that displacement. [0019] The shoe attachment device 1 , an example of which is shown in the accompanying drawings, comprises two main components: a metatarsal guard 2 and a lip 4 . In a preferred embodiment, the metatarsal guard 2 is a substantially convex shell formed by a flat or slightly arcuate central portion 12 that is laterally flanked by more downwardly curved left and right portions 14 , 16 . In some embodiments, however, the metatarsal guard 2 may have a more uniformly arcuate structure with no distinctive left, right and center portions. Regardless, the guard 2 has a longitudinal width such that, when properly installed onto a laced shoe 30 , the guard 2 convers the front portion of the metatarsal region of the foot without extending into the phalangeal region, as may be gleaned from viewing FIG. 3 . [0020] The forward end of at least the central portion 12 of the metatarsal guard 2 is met by a planar lip 4 which is vertically oriented to be roughly perpendicular to the plane of the guard central portion 12 (to the extent that any part of the central portion 12 is planar) and give the device 1 an overall L-shaped profile when viewed from its right or left side. Preferably, a rounded crease is formed at the junction of the guard 2 and lip 4 to strengthen the joint. It is also preferable that the guard 2 and lip 4 be fabricated of an elastic, but rigid, material. Some plastics and rubbers are suitable, but a plastic may be most preferable due to its lighter weight. [0021] To improve wearer comfort, adhered to the underside (i.e., the foot side surface) of the metatarsal guard 2 as well as the base of the lip 4 is resilient material, such as a resilient foam, in the form of either a single continuous cushion or distinct guard and lip cushions 6 , 8 . Preferably, the lip cushion 8 (or portion of a unitary cushion that is positioned underneath the lip 4 ) is thicker than is the adjacent guard cushion 6 (or cushion portion positioned underneath the guard 2 ). That is because when a user properly positions the device 1 against a dolly axle 20 as shown in FIG. 3 , pulling the foot horizontally so that the lip 4 , not the guard 2 , forcefully presses against the axle 20 causes the device 1 to press downward into the wearer's foot most pronouncedly at the base of the lip 4 . [0022] Finally, formed within each of the left and right portions 14 , 16 of the metatarsal guard 2 is at least one hole 18 through which shoelaces are to be threaded in order to secure the attachment 1 to a shoe 30 , as can be seen in FIG. 3 [0023] Aspects of various embodiments of the present invention that are not recited above or claimed below may be noted from observing the illustrations included herein.
A shoe attachment device having a front metatarsal covering shell and a vertical lip used for wedging against a hand truck wheel axle in order to pull the hand truck by foot without straining the foot or toes. Holes formed in the metatarsal shell allow the device to be securely attached to a laced shoe via shoelaces.
Concisely explain the essential features and purpose of the invention.
[ "BACKGROUND [0001] The present invention generally relates to shoe attachment devices, and it is specifically directed to a device that is attachable to the metatarsal area of a laced shoe so as to assist its wearer in using a leg to pull a loaded hand truck out from underneath a heavy load placed thereupon without subjecting the foot to undue blunt trauma or potentially injurious strain.", "[0002] Foot injuries not caused by running or jumping are, typically, caused by any one of three things: (a) accidental striking of the metatarsal or toe area of the foot by falling objects;", "(b) accidental striking of the heel or toe area of the foot against lying or erected objects;", "or (c) deliberate striking of the metatarsal or toe area of the foot against sporting balls and other objects.", "Protecting the foot against these typical causes of injury is achieved through either shoe construction or use of an extraneous (to the shoe) protective device.", "[0003] Shoe designs for protecting against injuries caused by either of the two aforementioned types of accidental foot striking events often feature metal or hard plastic reinforced toe and/or heel portions of the upper, or “vamp,” part of the shoe.", "In some cases, these protective shoe uppers also have built into them rigid devices that cover the metatarsal area of the foot.", "One such example is found in U.S. Pat. No. 7,328,526 to Peterson.", "Peterson discloses a shoe upper having a metatarsal guard formed within it.", "The guard is a rigidly flexible convex piece that extends from the rear of the wearer's toes to the top of the wearer's instep.", "Shoes and boots having uppers that are configured to be protective are standard attire for industrial workers, for example.", "However, because of their rigidity and, typically, their non-breathability, these kinds of footwear are generally preferred for use in the physical labor environment, but not so much for casual wear and certainly not for use in athletic activities in which the risk of the foot impacting anything other than the ground is minimal (e.g., running, weightlifting, etc.).", "Consequently, the prior art is replete with devices that are removably attachable to shoes for the purpose of protecting users'", "feet from injuries caused by any of the aforementioned three types of foot striking events.", "[0004] For example, U.S. Pat. No. 8,959,801 to Siragusa discloses an ankle and foot protector device for attaching to a hockey skate.", "The Siragusa device is formed by a generally rectangular instep protector pad that covers the length of the instep and a transversely oriented ankle protector pad.", "Pairs of laterally spaced holes formed in each pad that allow skate laces to be threaded through them, coupled with a strap of hook and loop fastener material, permits the device to be securely mounted to the skate.", "The two pads are configured to be effective in protecting a wearer's foot from the high impact of a flying hockey puck.", "However, they, theoretically, could be mounted to a different type of footwear to protect the foot in other contexts.", "[0005] Nevertheless, despite the ample number of existent foot protection devices that are configured to prevent foot injury caused by any of the three common types of foot impact events described above, that the present inventor is aware, there is no prior art device configured specifically to prevent the type of foot discomfort and injury that might be result from removing loads from a hand truck in a particular manner.", "[0006] A common type of hand truck, or “dolly,” is a two-wheeled, L-shaped apparatus that features a horizontal, load-supporting platform and axle-mounted wheels, at its lower end, which are connected, by a vertical support structure, to one or two handles situated at its upper end.", "The purpose of a dolly is to transport boxes and other items that are too heavy or too large to be simply lifted and carried to a destination without enormous physical strain and with much greater efficiency than carrying them by hand.", "This is accomplished by placing a load to be hauled atop the dolly platform and using the handle(s) to rock the apparatus backward so that the platform and load are rotated off the ground—causing the vertical support structure and the platform to cradlingly support the load while only the wheels are contacting the ground.", "[0007] Often, with heavier loads, it is helpful for a user to place his or her foot atop the wheel axle in order to gain leverage when rocking the dolly backward to lift its loaded platform.", "Using the foot in this manner is usually non-problematic because the sole of the shoe dampens the impact between the bottom of the foot and the dolly's steel axle rod.", "However, the same cannot be said for the foot maneuver that is often employed to remove the load from the dolly platform upon arriving at the drop-off destination at the end of the haul.", "More specifically, in effort to be more time efficient, if not to simply to avoid the physical arduousness of removing the load item(s) from the dolly platform by hand, one might be inclined to simply pull the dolly such that its ground-resting platform slides out from underneath the still sitting load that has a bottom surface area which extends beyond the surface area of the dolly platform.", "And since pulling at the vertically higher handle(s) would generate torque that would, initially, cause the platform to vertically lift, rather than horizontally slide, one might use a foot and leg to pull horizontally on the dolly at its lower end.", "This can be accomplished by placing a foot underneath the wheel axle and lifting the toes upward so that the axle is wedged into the crease formed at the meeting of the front metatarsal area of the foot and the toes—rendering the toes a vertical barrier against the axle in order that leg muscles, rather than upper body muscles, are exerted to deliver the pulling force needed to withdraw the horizontal platform from underneath the heavy load.", "[0008] For persons in the ground freight and product distribution industries who routinely use dollies to move heavy stacks of boxes and other items and who must work quickly, this leg-pulling technique is often used repeatedly to unload dollies.", "Unfortunately, the resulting blunt trauma sustained by the more tender top of the foot can cause painful bruising, fatigued foot and calf muscles and even more debilitating injury.", "However, again, the present inventor is not aware of any shoe-mountable aids for alleviating pressure on the foot and reducing the discomfort and risk of injury caused by this dolly pulling maneuver.", "More specifically, while many of the prior art protective devices may be configured so as to dampen any impact that might occur between the metatarsal area of the foot and a dolly axle, they are not configured to be able to hook or cradle the axle without the wearer having to curl his toes upward and around the axle in order that toes become a somewhat vertical support that presses against the axle and allows the leg to pull the lower end of the dolly such that the dolly platform may simply be slid out from under its load, rather than be tilted into lifting the load from the ground.", "[0009] Consequently, the present inventor appreciates a need for a device that: (1) can be easily and securely attached to a laced shoe;", "(2) enables a user to use his leg to apply pulling force to the wheel axle of a dolly without having to curl his entire foot or toes upward to cradle the axle;", "and (3) is configured such that it minimizes the likelihood that that leg pulling motion causes discomforting or injurious strain to be placed on the user's foot.", "The present invention for a shoe-mounted dolly pulling device substantially fulfills these needs.", "SUMMARY [0010] In order for a dolly operator to separate a large load from a dolly platform by removing the dolly from the load, rather than by removing the load from the dolly, the operator must pull the dolly horizontally toward himself.", "More specifically, he must pull on the dolly at its lower end and not its upper, handle end.", "That is because, if the pulling force is applied at the upper end of the dolly, the weight of the load will cause the dolly wheels to act as a fulcrum, and the platform will rotate vertically upward, rather than it sliding horizontally toward the operator's body.", "Therefore, to avoid the discomfort, upper body strain and potential back injury that might result from crouching and pulling on the lower end of the hand truck with the hands, a dolly operator will typically engage the dolly wheel axle with one of his feet and use that leg to pull the lower end of the dolly toward him—allowing bottom surface area of the load that extends beyond the dolly platform to engage the ground and resist sliding along with the platform due to ground friction.", "Although a time saving maneuver, repeatedly doing this can greatly strain the delicate toe and foot muscles and the lower leg muscles that must be exerted to keep the axle cradled within the crease formed at the meeting of the front metatarsal and phalangeal regions of the foot and to deliver sufficient pulling force to slide the dolly while the axle presses against the toes.", "This repeated action can also strain, and potentially rupture, the Achilles tendon, much less cause severe foot bruising and soreness.", "[0011] Therefore, it is an object of the present invention to provide a device that, when attached to a shoe, is configured to enable its wearer to perform the aforementioned leg pulling technique on a loaded dolly without even utilizing many of the same foot and leg muscles—at least not to any great extent—that would be exerted without the aid of the present device.", "In one aspect of the invention, the present device is formed by a convexly-shaped metatarsal guard that inserts into a shoe to fit atop the front metatarsal area of the foot and an upward extending lip that resides at the front end of the guard to give the device an L-shaped profile.", "So, instead of the wearer's foot and toes having to cradle the dolly axle, the device hooks around the axle with the lip forming a vertical structure that presses against the axle when the sole of the foot is held parallel to the ground and the foot is drawn along a horizontal plane away from the load.", "As a consequence, the user does not have to curl his toes upward or keep any muscles of the metatarsal or toes tensed in order to maintain that foot posture against heavy resistance imposed by the dolly axle.", "This significantly reduces strain on the foot muscles and Achilles tendon.", "As another consequence, the greatest resistance force imposed by the dolly axle (due to the weight of the load atop the dolly platform) is applied directly the device lip and not to the top of the foot.", "[0012] It is another object of the invention to eliminate the foot bruising that currently occurs along the area of contact between the foot and the dolly axle when a dolly operator uses a leg to pull the dolly from underneath a load.", "In another aspect of the invention, the present device features resilient padding material underneath (on the foot side of) the metatarsal guard and the lip.", "Therefore, when the device is torqued by its lip being pressed against the axle, resilient material, not the rigid material that forms the metatarsal guard and the device lip nor the metal of the dolly axle, presses against the foot.", "Because the impact that is applied to the foot is both (1) softened by the padding material and (2) distributed over much, if not all, of the padded undersides of the lip and metatarsal guard (a composite surface area that is significantly broader than is the shoe surface area that would otherwise be in direct contact with the dolly axle), bruising is much less likely to occur than if same maneuver is performed without the present device.", "[0013] Finally, it is another object of the present invention to be so unencumbering to wearers of casual and athletic shoes that, once installed onto a laced shoe, the user will not feel compelled to ever remove the present device in order to wear the shoe free of the device when not operating a dolly.", "In other words, the object is for the device to be immaterial to the general functionality and performance of the shoe to which it is attached so as to obviate the need to detach the device or change shoes after dolly use and before engaging in other activities.", "In another aspect of the invention, present device is lightweight, its metatarsal covering portion is contoured to generally conform to the foot, its lip portion has a fairly low profile and its underside is cushioned.", "Furthermore, the laterally outer areas of the metatarsal covering portion have apertures formed within them to allow shoe laces to be threaded through the device to securely anchors it to the forward metatarsal area of the shoe without covering the toes or obstructing their movement.", "Consequently, the present device can remain perpetually installed onto, say, an athletic shoe without appreciably inhibiting any movements or sacrificing any comfort during non-dolly related wear.", "BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a right perspective view of the shoe attachment device in accordance with the present disclosure;", "[0015] FIG. 2 is another perspective view of the same;", "and [0016] FIG. 3 is a right perspective view of the same, the device being shown attached to a show and engaging a dolly wheel axle.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0017] Referring now to FIGS. 1 and 2 , there is illustrated a preferred embodiment of the shoe attachment device 1 of the present invention.", "The present device 1 is attachable to a laced shoe 30 , as shown in FIG. 3 , and it enables the user to hook and horizontally pull on the wheel axle 20 of a common hand truck with his or her leg.", "[0018] Generally speaking, when a load-carrying hand truck, or “dolly,” is sitting upright on the ground, the load that it is used to haul rests on the platform part (not shown) of the dolly while the platform is flush against the ground.", "Therefore, if the bottom surface area of the load is more expansive than is the surface area of the dolly platform, part of that load bottom surface will be separated from the ground only due the thickness of the dolly platform, and some of it may even be contacting the ground while the dolly is at rest.", "Of course, if not already contacting the ground, it can be easily put in contact with the ground by the dolly operator slightly tilting the dolly forward.", "In any event, a portion of the load bottom surface being in contact with the ground allows for friction between those surfaces to produce relative movement of the platform and the load when the dolly is pulled horizontally.", "More specifically, application of pulling force to the dolly may cause the dolly platform to travel horizontally while ground friction causes load item remain(s) to remain in place such that, eventually, the load is entirely resting upon the ground and the dolly platform is entirely removed from underneath it.", "The shoe attachment device 1 of the present invention facilitates that displacement.", "[0019] The shoe attachment device 1 , an example of which is shown in the accompanying drawings, comprises two main components: a metatarsal guard 2 and a lip 4 .", "In a preferred embodiment, the metatarsal guard 2 is a substantially convex shell formed by a flat or slightly arcuate central portion 12 that is laterally flanked by more downwardly curved left and right portions 14 , 16 .", "In some embodiments, however, the metatarsal guard 2 may have a more uniformly arcuate structure with no distinctive left, right and center portions.", "Regardless, the guard 2 has a longitudinal width such that, when properly installed onto a laced shoe 30 , the guard 2 convers the front portion of the metatarsal region of the foot without extending into the phalangeal region, as may be gleaned from viewing FIG. 3 .", "[0020] The forward end of at least the central portion 12 of the metatarsal guard 2 is met by a planar lip 4 which is vertically oriented to be roughly perpendicular to the plane of the guard central portion 12 (to the extent that any part of the central portion 12 is planar) and give the device 1 an overall L-shaped profile when viewed from its right or left side.", "Preferably, a rounded crease is formed at the junction of the guard 2 and lip 4 to strengthen the joint.", "It is also preferable that the guard 2 and lip 4 be fabricated of an elastic, but rigid, material.", "Some plastics and rubbers are suitable, but a plastic may be most preferable due to its lighter weight.", "[0021] To improve wearer comfort, adhered to the underside (i.e., the foot side surface) of the metatarsal guard 2 as well as the base of the lip 4 is resilient material, such as a resilient foam, in the form of either a single continuous cushion or distinct guard and lip cushions 6 , 8 .", "Preferably, the lip cushion 8 (or portion of a unitary cushion that is positioned underneath the lip 4 ) is thicker than is the adjacent guard cushion 6 (or cushion portion positioned underneath the guard 2 ).", "That is because when a user properly positions the device 1 against a dolly axle 20 as shown in FIG. 3 , pulling the foot horizontally so that the lip 4 , not the guard 2 , forcefully presses against the axle 20 causes the device 1 to press downward into the wearer's foot most pronouncedly at the base of the lip 4 .", "[0022] Finally, formed within each of the left and right portions 14 , 16 of the metatarsal guard 2 is at least one hole 18 through which shoelaces are to be threaded in order to secure the attachment 1 to a shoe 30 , as can be seen in FIG. 3 [0023] Aspects of various embodiments of the present invention that are not recited above or claimed below may be noted from observing the illustrations included herein." ]
FIELD OF THE INVENTION [0001] The present invention relates to the field of communications, and particularly to a data processing method and device. BACKGROUND OF THE INVENTION [0002] It is very strict with delay requirement for bearing a real-time service in a packet domain in wireless communication. The delay is typically limited within a range from 80 to 150 ms for transmission of a data packet of a real-time voice service via an air interface and limited to approximately 300 ms for transmission of a data packet of a real-time video service via an air interface. [0003] A transmission delay experienced by a data packet via an air interface generally includes two parts, i.e. a wait delay in a buffer of a transmitter side and a transmission delay during transmission. The wait delay generally depends upon a system congestion condition, and the transmission delay depends upon a transmitting capacity of an air interface channel and a capacity of a receiver side to process the received data packet, that is, the transmission delay includes a period of time required for transmission, reception, feedback and corresponding processing of the data packet. [0004] Since it is very strict with delay requirement for a real-time service, if a data packet is subject to an excessively long wait delay in the buffer of the transmitter side, then the data packet may not contribute to a quality of service even though it is subsequently transmitted and correctly received, and on the contrary, a valuable resource of the air interface may be wasted, thus resulting in an increased wait delay of a subsequent data packet. In order to address this issue, a discard timer is provided at the transmitter side, and such a data packet that waits in the buffer of the transmitter side for a delay exceeding a packet discard threshold (i.e., the maximum wait delay) preset by the discard timer is discarded, to improve the efficiency of transmission via the resource of the air interface and reduce a wait delay of a subsequent data packet. The presetting of the packet discard threshold is of a significant influence on the packet loss rate and the transmission efficiency of the system, for example, a relatively small preset packet discard threshold may result in a relatively large packet loss rate; and a relatively large preset packet discard threshold may result in degraded transmission efficiency and an increased wait delay of a subsequent data packet. A method for presetting a packet discard threshold in the prior art lies in that: a period of time required for the largest number of transmissions via the air interface is reserved in the total delay of the air interface, that is, the packet discard threshold is determined as the difference between the total delay of the air interface and the period of time required for the largest number of transmissions via the air interface. For example, as illustrated in FIG. 1 , T budget represents the total delay of the air interface, N trans represents the largest number of transmissions of the system, T trans represents a period of time for each transmission, and T threshold represents the packet discard threshold, accordingly, T threshold =T budget −N trans ×T trans . A data packet waiting in the buffer for a delay exceeding the packet discard threshold is discarded. Unfortunately in this method, a data packet can only be discarded prior to its first transmission, and the timer for the data packet is reset to zero upon commence of the first transmission. [0005] In view of the above, the packet discard threshold preset in the foregoing method has the following disadvantages. [0006] 1. Since the period of time occupied for the largest number of transmissions allowable for the system has to be accommodated, the packet discard threshold may be preset excessively short. However, the majority of data packets can be received correctly prior to reaching the largest number of transmissions in a well designed wireless system. Thus, a relatively short period of time experienced by a data packet in the buffer to wait for a first transmission may cause some data packets that can be received correctly without being subject to the largest number of transmissions to be discarded prematurely, especially in the event of a relatively short total delay of the air interface and a relatively poor quality of the channel, and the packet loss rate at the transmitter side may consequently be increased dramatically, thus degrading greatly the quality of service. [0007] For example, in the case that the total delay of the air interface is denoted as T budget , where T budget =150 ms, the largest number of transmissions of the system is denoted as N trans , where N trans =4, a period of time occupied for each round-trip transmission is denoted as T RTT , where T RTT =20 ms, and the packet discard threshold is denoted as T threshold , then T threshold =150 −4×20=70 ms as preset in the foregoing method, that is, a data packet waiting in a buffer of a transmitter for its first transmission for a period of time exceeding 70 ms is to be discarded. Actually, the majority of data packets may be transmitted successfully without being subject to four times of transmissions, and some data packets may be transmitted successfully even during the first transmission, in this case, a data packet is still valid even if it is transmitted for the first time after waiting in the buffer for 150−1×20=130 ms. [0008] 2. Presetting of a packet discard threshold is dependent upon the total delay of the air interface, the largest number of transmissions of the system and the period of time occupied for each round-trip transmission, and when these conditions remain unchanged, the same packet discard threshold is to be preset even for data packets of different users or different data packets of the same user. However, channel statuses of users vary, and this method for presetting a packet discard threshold can not enable a data packet to be discarded properly dependent upon a practical condition, thus possibly resulting in a relatively large packet loss rate and a relatively low utilization efficiency of the resource of the air interface. [0009] 3. Such a mechanism, in which a monitoring process of whether to discard a data packet is disabled after the first transmission of the data packet and it is assumed that an event of discarding the data packet will not occur during subsequent possible retransmission, may be unreasonable, because channel and system loads and hence a delay due to retransmission vary dynamically. If the sum of an actual transmission delay occupied for the first transmission and retransmission of a data packet and a wait delay occupied for the data packet exceeds the total delay of the air interface, it indicates that subsequent transmission of the data packet is useless and the data packet shall be discarded. SUMMARY OF THE INVENTION [0010] Embodiments of the invention provide a data processing method and device to address the disadvantages of an increased packet loss rate or a degraded transmission efficiency due to an unreasonably preset packet loss threshold in the prior art. [0011] An embodiment of the invention provides a data processing method including: [0012] determining a predicated transmission period of time required for transmitting a data packet and a stay period of time during which the data packet stays in a buffer; and [0013] discarding the data packet when the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface. [0014] An embodiment of the invention provides a data processing device including: [0015] a predicated transmission period of time determination module configured to determine a predicated transmission period of time required for transmitting a data packet for transmission; [0016] a stay period of time determination module configured to determine a stay period of time during which the data packet stays in a buffer; [0017] a calculation module configured to calculate the sum of the predicated transmission period of time and the stay period of time; and [0018] a processing module configured to discard the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface. [0019] Embodiments of the invention adjust dynamically the time when a data packet for transmission is to be discarded by taking into account both a predicated transmission period of time for transmitting the data packet and a stay period of time during which the data packet stays in a buffer, to thereby reduce a packet loss rate and improve a quality of service. BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIG. 1 is a schematic diagram of determining a packet discard threshold in the prior art; [0021] FIG. 2 is a schematic flow diagram of a method for transmitting a data packet according to a first embodiment of the invention; [0022] FIG. 3 is a schematic diagram of a simulation result of a solution according to an embodiment of the invention; and [0023] FIG. 4 is a schematic diagram of a structure of a data processing device according to a third embodiment of the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS [0024] In order to attain an object of the invention, in the case of a service with strict delay requirement (e.g., a Voice over Internet Protocol (VoIP) service), times for packet discarding are determined dynamically for data packets of different users or different data packets of the same user, to make a packet discard mechanism more reasonable. [0025] Respective embodiments of the invention are detailed hereinafter in connection with the drawings. [0026] Reference is made to FIG. 2 which illustrates a schematic flow diagram of a method for transmitting a data packet according to a first embodiment of the invention, and as may be apparent from FIG. 2 , this method includes the following operations 201 to 206 . [0027] Operation 201 : it is determined whether a data packet for transmission has been subject to a number of transmissions more than the largest number of transmissions, and if so, then the operation 206 is executed; otherwise, the operation 202 is executed. [0028] The largest number of transmissions in the present embodiment may be determined from a parameter of a transmission system per se or empirically, but the invention is not limited in this respect. [0029] The data packet for transmission may be a data packet arranged in the first place of a buffer. [0030] Operation 202 : a predicated transmission period of time required for transmitting the data packet for transmission is determined. [0031] In the present embodiment, the predicated transmission period of time may be determined empirically or from a parameter such as a channel status. A period of time for transmission of a data packet includes but not limited to the following two definitions. [0032] 1. A period of time for transmission of a data packet=A period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet. [0033] 2. A period of time for transmission of a data packet=A period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information. [0034] (1) The predicated transmission period of time of the data packet for transmission may be determined from a transmission period of time of any previously transmitted data packet: [0035] the predicated transmission period of time=a period of time for the any data packet to travel from the transmitter side to the receiver side+a period of time occupied for the receiver side to process the any data packet; or [0036] the predicated transmission period of time=a period of time for the any data packet to travel from the transmitter side to the receiver side+a period of time occupied for the receiver side to process the any data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information. [0037] (2) The predicated transmission period of time of the data packet for transmission may be determined from an average of transmission periods of time occupied for N previously transmitted data packets, where N is an integer larger than one. Description of a specific determination process thereof is omitted here. [0038] Operation 203 : a stay period of time during which the data packet for transmission stays in a buffer is determined. [0039] If the data packet is to be transmitted for the first time, then: [0040] the stay period of time during which the data packet stays in the buffer=a period of time during which the data packet waits for the first transmission in the buffer. [0041] If the data packet has been transmitted for M (M is larger than 1) times, then: [0042] the stay period of time during which the data packet stays in the buffer=a period of time during which the data packet waits for the first transmission in the buffer+a period of time for the data packet to wait for being scheduled+the sum of round-trip transmission periods of time occupied for the M times of performed transmission processes. [0043] Particularly, the period of time for the data packet in waiting for being scheduled=the sum of periods of time from the ending of the former of every two adjacent round-trip transmissions to the starting of the latter of the two adjacent round-trip transmissions among the M round-trip transmission processes and the ongoing round-trip transmission process. [0044] Here, the round-trip transmission period of time occupied for each performed transmission process=the period of time for the data packet to travel from the transmitter side to the receiver side+the period of time occupied for the receiver side to process the received data packet+the period of time occupied for the receiver side to transmit feedback information+the period of time for the transmitter side to process the feedback information. [0045] Operation 204 : it is determined whether the sum of the predicated transmission period of time and the stay period of time during which the data packet stays in the buffer exceeds a system-tolerable delay of an air interface, and if so, then the operation 206 is executed; otherwise, the operation 205 is executed. [0046] In the present embodiment, the operations 202 and 203 can be executed in a variable order. [0047] Operation 205 : the data packet is transmitted with the number of transmissions being incremented by one. If this transmission fails and the data packet is to be retransmitted, then the operation 201 is executed. [0048] Operation 206 : the data packet is discarded. [0049] The method according to the first embodiment is explained in detailed hereinafter in connection with a specific example of a second embodiment. [0050] In the second embodiment of the invention, a system-tolerable delay of an air interface T budget is 80 ms, the largest number of transmissions is four (the largest number of retransmissions is three), and a period of time for transmission of a data packet is determined as the sum of a period of time for the data packet to travel from a transmitter side to a receiver side and a period of time occupied for the receiver side to process the data packet, then a data packet is processed at the transmitter side in the following method. [0051] In the first operation, when the data packet is to be transmitted for the first time, a stay period of time during which the data packet stays in a buffer is determined as a period of time T 0 during which the data packet waits for the first transmission in the buffer, where T 0 =20 ms, and a predicated period of time for the first transmission of the data packet T trans 1— estimate is determined, where T trans 1— estimate =5 ms. Thus, T trans 1— estimate +T 0 =20 ms<T budget , and the data packet is transmitted normally. [0052] In the second operation, if the transmitter side receives and processes feedback information of a transmission failure after elapsing of a 12 ms delay (i.e., a round-trip transmission period of time T RTT 1 occupied for the first transmission, where T RTT 1 =12 ms), then the data packet is queued for the next transmission. [0053] In the third operation, if the data packet is to be retransmitted, and a period of time during which the data packet waits in the buffer since the first round-trip transmission ends until the second round-trip transmission is initiated is denoted as T wait 1 , where T wait 1 =20 ms, then the stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 =52 ms; a predicated period of time for the second transmission of the data packet T trans 2— estimate is determined, where T trans 2— estimate =5 ms. Due to the fact that T 0 +T wait 1 +T RTT 1 +T trans 2— estimate =57 ms<T budget , the data packet is transmitted normally. [0054] In the fourth operation, if the transmitter side receives and processes feedback information of a transmission failure after elapsing of a 11 ms delay (i.e., a round-trip transmission period of time T RTT 2 occupied for the second transmission, where T RTT 2 =11 ms), then the data packet is queued for the next transmission. [0055] In the fifth operation, if the data packet is to be retransmitted, and a period of time during which the data packet waits in the buffer since the second round-trip transmission ends until the third round-trip transmission is initiated is denoted as T wait 2 , where T wait 2 =10 ms, then in analogy to the third operation, the stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 =73 ms; a predicated period of time for the third transmission of the data packet T trans 3— estimate is determined, where T trans 3— estimate =5 ms. Due to the fact that T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T trans 3— estimate =78 ms<T budget , the data packet is transmitted normally. [0056] In the sixth operation, the total stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T RTT 3 =84 ms>T budget after elapsing of a 11 ms delay again (i.e., a round-trip transmission period of time T RTT 3 occupied for the third transmission, where T RTT 3 =11 ms), and the data packet is discarded when it is arranged in the first place of the buffer again, regardless of whether the third transmission succeeds or fails. [0057] In the present second embodiment, if it a period of time for transmission of a data packet is equal to a period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information, then in the foregoing fifth operation, the determined predicated period of time for the third transmission of the data packet may possibly be drawn as T trans 3— estimate =11 ms, and in this case, the third transmission is not performed any longer and the data packet is discarded directly due to the fact that T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T trans 3— estimate =84 ms>T budget . [0058] In view of the above operations, if a data packet is to be transmitted, the sum of a stay period of time at the transmitter side and a predicated transmission period of time of the data packet may be denoted with formula (1) suitable for that the data packet is to be transmitted for the first time, and formula (2) suitable for that the data packet is to be retransmitted, [0000] T = T 0 + T trans_estimate ( 1 ) T = T 0 + ∑ i = 1 M   T wait i + ∑ i = 1 M  T RTT i + T trans_estimate ( 2 ) [0059] T denotes the sum of the wait period of time occupied for the data packet and the predicated transmission period of time thereof, T 0 denotes the period of time during which the data packet waits for the first transmission in the buffer, T trans — estimate denotes the predicated transmission time required for the ongoing transmission of the data packet [0000] ∑ i = 1 M   T wait i [0000] denotes the sum of periods of time for the data packet in waiting for being scheduled from the ending of the former of every two adjacent round-trip transmissions to the starting of the latter of the two adjacent round-trip transmissions among performed round-trip transmission processes and the ongoing round-trip transmission process (M denotes the number of times that the data packet has been transmitted); and [0000] ∑ i = 1 M  T RTT i [0000] denotes the sum of round-trip transmission periods of time occupied for respective transmissions (the round-trip transmission period of time is equal to a sum of a period of time for transmission of the data packet from the transmitter side to the receiver side, a period of time occupied for the receiver side to process the data packet, a period of time occupied for the receiver side to transmit feedback information and a period of time for the transmitter side to process the feedback information). [0060] The method according to an embodiment of the invention may be applied in a simulation experiment, for example, in a system of Time Division duplex-Synchronous Code Division Multiple Access High Speed Uplink Packet Access (TD-SCDMA HSUPA), and for a VoIP service in use, where the maximum delay of an air interface tolerable to the system is 80 ms, a round-trip transmission period of time is 15 ms, and the largest number of transmissions of the system is four (i.e., the number of retransmissions is three), in this case a simulation result is as illustrated schematically in FIG. 3 . As may be apparent from FIG. 3 , in the event of a traditional solution using the largest number of retransmissions of three, a reserved period of time required for the largest number of transmissions is 60 ms, and the remaining 20 ms is taken as a packet discard threshold, therefore this solution can support at most only three users per sector. In contrast, the solution in the present embodiment eliminates the need of reserving a period of time required for the largest number of transmissions and can enable flexible control in response to an actual network status to support at most five users per sector, thereby improving a capacity of the system by 66%. [0061] A third embodiment of the invention provides a data processing device corresponding to the data processing method in the first embodiment with a structure as illustrated schematically in FIG. 4 , which includes a predicated transmission period of time determination module 11 , a stay period of time determination module 12 , a calculation module 13 and a processing module 14 , where the predicated transmission period of time determination module 11 is configured to determine a predicated transmission period of time required for transmitting a data packet for transmission; the stay period of time determination module 12 is configured to determine a stay period of time during which the data packet for transmission stays in a buffer; the calculation module 13 is configured to calculate the sum of the predicated transmission period of time and the stay period of time; and the processing module 14 is configured to discard the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface. [0062] Moreover, the processing module 14 may further be configured to transmit the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time does not exceed the preset delay of an air interface. [0063] Moreover, the device further includes a transmission counting module 15 configured to increment a recorded number of transmissions of the data packet by one after the processing module 14 has transmitted the data packet. [0064] The device further includes a transmission number determination module 16 configured to trigger the predicated transmission period of time determination module 11 and the stay period of time determination module 12 upon determining that the number of transmissions of the data packet for transmission does not exceed the largest number of transmissions. [0065] With the method and device according to the embodiments of the invention, times for packet discarding for data packets of different users and different data packets of the same user can be adjusted dynamically in response to an actual condition of a transmission system to make full use of a service delay budget, reduce a packet loss rate in a buffer at a transmitter side, improve a quality of service, as well as improve the capacity of the system in which a service with a strict delay requirement is borne. Moreover, when an embodiment of the invention is applied in a system of a High Speed Downlink Packet Access (HSDPA), a protocol of the system is subject to minor modifications, and good performance of the system can be achieved with simple operations in the event that the system operates normally. [0066] Evidently, those skilled in the art can make various modifications and variations to the invention without departing from the scope of the invention. Thus, the invention is also intended to encompass these modifications and variations of the invention provided these modifications and variations come into the scope of the appended claims and their technical equivalents.
A method for data processing is provided, the method comprises: determining the predicted transmission time required by the data packet to be transmitted currently during the transmission course and the residence time for the data packet residing in the buffer; when the sum of the predicted transmission time and the residence time is greater than the predetermined air interface time delay, discarding the data packet. By utilizing the technical scheme of the invention, the discarding time of the data packet is dynamically adjusted, the packet discarding rate is reduced, and the service quality is improved. An apparatus for data processing is also provided.
Identify the most important claim in the given context and summarize it
[ "FIELD OF THE INVENTION [0001] The present invention relates to the field of communications, and particularly to a data processing method and device.", "BACKGROUND OF THE INVENTION [0002] It is very strict with delay requirement for bearing a real-time service in a packet domain in wireless communication.", "The delay is typically limited within a range from 80 to 150 ms for transmission of a data packet of a real-time voice service via an air interface and limited to approximately 300 ms for transmission of a data packet of a real-time video service via an air interface.", "[0003] A transmission delay experienced by a data packet via an air interface generally includes two parts, i.e. a wait delay in a buffer of a transmitter side and a transmission delay during transmission.", "The wait delay generally depends upon a system congestion condition, and the transmission delay depends upon a transmitting capacity of an air interface channel and a capacity of a receiver side to process the received data packet, that is, the transmission delay includes a period of time required for transmission, reception, feedback and corresponding processing of the data packet.", "[0004] Since it is very strict with delay requirement for a real-time service, if a data packet is subject to an excessively long wait delay in the buffer of the transmitter side, then the data packet may not contribute to a quality of service even though it is subsequently transmitted and correctly received, and on the contrary, a valuable resource of the air interface may be wasted, thus resulting in an increased wait delay of a subsequent data packet.", "In order to address this issue, a discard timer is provided at the transmitter side, and such a data packet that waits in the buffer of the transmitter side for a delay exceeding a packet discard threshold (i.e., the maximum wait delay) preset by the discard timer is discarded, to improve the efficiency of transmission via the resource of the air interface and reduce a wait delay of a subsequent data packet.", "The presetting of the packet discard threshold is of a significant influence on the packet loss rate and the transmission efficiency of the system, for example, a relatively small preset packet discard threshold may result in a relatively large packet loss rate;", "and a relatively large preset packet discard threshold may result in degraded transmission efficiency and an increased wait delay of a subsequent data packet.", "A method for presetting a packet discard threshold in the prior art lies in that: a period of time required for the largest number of transmissions via the air interface is reserved in the total delay of the air interface, that is, the packet discard threshold is determined as the difference between the total delay of the air interface and the period of time required for the largest number of transmissions via the air interface.", "For example, as illustrated in FIG. 1 , T budget represents the total delay of the air interface, N trans represents the largest number of transmissions of the system, T trans represents a period of time for each transmission, and T threshold represents the packet discard threshold, accordingly, T threshold =T budget −N trans ×T trans .", "A data packet waiting in the buffer for a delay exceeding the packet discard threshold is discarded.", "Unfortunately in this method, a data packet can only be discarded prior to its first transmission, and the timer for the data packet is reset to zero upon commence of the first transmission.", "[0005] In view of the above, the packet discard threshold preset in the foregoing method has the following disadvantages.", "[0006] 1.", "Since the period of time occupied for the largest number of transmissions allowable for the system has to be accommodated, the packet discard threshold may be preset excessively short.", "However, the majority of data packets can be received correctly prior to reaching the largest number of transmissions in a well designed wireless system.", "Thus, a relatively short period of time experienced by a data packet in the buffer to wait for a first transmission may cause some data packets that can be received correctly without being subject to the largest number of transmissions to be discarded prematurely, especially in the event of a relatively short total delay of the air interface and a relatively poor quality of the channel, and the packet loss rate at the transmitter side may consequently be increased dramatically, thus degrading greatly the quality of service.", "[0007] For example, in the case that the total delay of the air interface is denoted as T budget , where T budget =150 ms, the largest number of transmissions of the system is denoted as N trans , where N trans =4, a period of time occupied for each round-trip transmission is denoted as T RTT , where T RTT =20 ms, and the packet discard threshold is denoted as T threshold , then T threshold =150 −4×20=70 ms as preset in the foregoing method, that is, a data packet waiting in a buffer of a transmitter for its first transmission for a period of time exceeding 70 ms is to be discarded.", "Actually, the majority of data packets may be transmitted successfully without being subject to four times of transmissions, and some data packets may be transmitted successfully even during the first transmission, in this case, a data packet is still valid even if it is transmitted for the first time after waiting in the buffer for 150−1×20=130 ms.", "[0008] 2.", "Presetting of a packet discard threshold is dependent upon the total delay of the air interface, the largest number of transmissions of the system and the period of time occupied for each round-trip transmission, and when these conditions remain unchanged, the same packet discard threshold is to be preset even for data packets of different users or different data packets of the same user.", "However, channel statuses of users vary, and this method for presetting a packet discard threshold can not enable a data packet to be discarded properly dependent upon a practical condition, thus possibly resulting in a relatively large packet loss rate and a relatively low utilization efficiency of the resource of the air interface.", "[0009] 3.", "Such a mechanism, in which a monitoring process of whether to discard a data packet is disabled after the first transmission of the data packet and it is assumed that an event of discarding the data packet will not occur during subsequent possible retransmission, may be unreasonable, because channel and system loads and hence a delay due to retransmission vary dynamically.", "If the sum of an actual transmission delay occupied for the first transmission and retransmission of a data packet and a wait delay occupied for the data packet exceeds the total delay of the air interface, it indicates that subsequent transmission of the data packet is useless and the data packet shall be discarded.", "SUMMARY OF THE INVENTION [0010] Embodiments of the invention provide a data processing method and device to address the disadvantages of an increased packet loss rate or a degraded transmission efficiency due to an unreasonably preset packet loss threshold in the prior art.", "[0011] An embodiment of the invention provides a data processing method including: [0012] determining a predicated transmission period of time required for transmitting a data packet and a stay period of time during which the data packet stays in a buffer;", "and [0013] discarding the data packet when the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface.", "[0014] An embodiment of the invention provides a data processing device including: [0015] a predicated transmission period of time determination module configured to determine a predicated transmission period of time required for transmitting a data packet for transmission;", "[0016] a stay period of time determination module configured to determine a stay period of time during which the data packet stays in a buffer;", "[0017] a calculation module configured to calculate the sum of the predicated transmission period of time and the stay period of time;", "and [0018] a processing module configured to discard the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface.", "[0019] Embodiments of the invention adjust dynamically the time when a data packet for transmission is to be discarded by taking into account both a predicated transmission period of time for transmitting the data packet and a stay period of time during which the data packet stays in a buffer, to thereby reduce a packet loss rate and improve a quality of service.", "BRIEF DESCRIPTION OF THE DRAWINGS [0020] FIG. 1 is a schematic diagram of determining a packet discard threshold in the prior art;", "[0021] FIG. 2 is a schematic flow diagram of a method for transmitting a data packet according to a first embodiment of the invention;", "[0022] FIG. 3 is a schematic diagram of a simulation result of a solution according to an embodiment of the invention;", "and [0023] FIG. 4 is a schematic diagram of a structure of a data processing device according to a third embodiment of the invention.", "DETAILED DESCRIPTION OF THE EMBODIMENTS [0024] In order to attain an object of the invention, in the case of a service with strict delay requirement (e.g., a Voice over Internet Protocol (VoIP) service), times for packet discarding are determined dynamically for data packets of different users or different data packets of the same user, to make a packet discard mechanism more reasonable.", "[0025] Respective embodiments of the invention are detailed hereinafter in connection with the drawings.", "[0026] Reference is made to FIG. 2 which illustrates a schematic flow diagram of a method for transmitting a data packet according to a first embodiment of the invention, and as may be apparent from FIG. 2 , this method includes the following operations 201 to 206 .", "[0027] Operation 201 : it is determined whether a data packet for transmission has been subject to a number of transmissions more than the largest number of transmissions, and if so, then the operation 206 is executed;", "otherwise, the operation 202 is executed.", "[0028] The largest number of transmissions in the present embodiment may be determined from a parameter of a transmission system per se or empirically, but the invention is not limited in this respect.", "[0029] The data packet for transmission may be a data packet arranged in the first place of a buffer.", "[0030] Operation 202 : a predicated transmission period of time required for transmitting the data packet for transmission is determined.", "[0031] In the present embodiment, the predicated transmission period of time may be determined empirically or from a parameter such as a channel status.", "A period of time for transmission of a data packet includes but not limited to the following two definitions.", "[0032] 1.", "A period of time for transmission of a data packet=A period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet.", "[0033] 2.", "A period of time for transmission of a data packet=A period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information.", "[0034] (1) The predicated transmission period of time of the data packet for transmission may be determined from a transmission period of time of any previously transmitted data packet: [0035] the predicated transmission period of time=a period of time for the any data packet to travel from the transmitter side to the receiver side+a period of time occupied for the receiver side to process the any data packet;", "or [0036] the predicated transmission period of time=a period of time for the any data packet to travel from the transmitter side to the receiver side+a period of time occupied for the receiver side to process the any data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information.", "[0037] (2) The predicated transmission period of time of the data packet for transmission may be determined from an average of transmission periods of time occupied for N previously transmitted data packets, where N is an integer larger than one.", "Description of a specific determination process thereof is omitted here.", "[0038] Operation 203 : a stay period of time during which the data packet for transmission stays in a buffer is determined.", "[0039] If the data packet is to be transmitted for the first time, then: [0040] the stay period of time during which the data packet stays in the buffer=a period of time during which the data packet waits for the first transmission in the buffer.", "[0041] If the data packet has been transmitted for M (M is larger than 1) times, then: [0042] the stay period of time during which the data packet stays in the buffer=a period of time during which the data packet waits for the first transmission in the buffer+a period of time for the data packet to wait for being scheduled+the sum of round-trip transmission periods of time occupied for the M times of performed transmission processes.", "[0043] Particularly, the period of time for the data packet in waiting for being scheduled=the sum of periods of time from the ending of the former of every two adjacent round-trip transmissions to the starting of the latter of the two adjacent round-trip transmissions among the M round-trip transmission processes and the ongoing round-trip transmission process.", "[0044] Here, the round-trip transmission period of time occupied for each performed transmission process=the period of time for the data packet to travel from the transmitter side to the receiver side+the period of time occupied for the receiver side to process the received data packet+the period of time occupied for the receiver side to transmit feedback information+the period of time for the transmitter side to process the feedback information.", "[0045] Operation 204 : it is determined whether the sum of the predicated transmission period of time and the stay period of time during which the data packet stays in the buffer exceeds a system-tolerable delay of an air interface, and if so, then the operation 206 is executed;", "otherwise, the operation 205 is executed.", "[0046] In the present embodiment, the operations 202 and 203 can be executed in a variable order.", "[0047] Operation 205 : the data packet is transmitted with the number of transmissions being incremented by one.", "If this transmission fails and the data packet is to be retransmitted, then the operation 201 is executed.", "[0048] Operation 206 : the data packet is discarded.", "[0049] The method according to the first embodiment is explained in detailed hereinafter in connection with a specific example of a second embodiment.", "[0050] In the second embodiment of the invention, a system-tolerable delay of an air interface T budget is 80 ms, the largest number of transmissions is four (the largest number of retransmissions is three), and a period of time for transmission of a data packet is determined as the sum of a period of time for the data packet to travel from a transmitter side to a receiver side and a period of time occupied for the receiver side to process the data packet, then a data packet is processed at the transmitter side in the following method.", "[0051] In the first operation, when the data packet is to be transmitted for the first time, a stay period of time during which the data packet stays in a buffer is determined as a period of time T 0 during which the data packet waits for the first transmission in the buffer, where T 0 =20 ms, and a predicated period of time for the first transmission of the data packet T trans 1— estimate is determined, where T trans 1— estimate =5 ms.", "Thus, T trans 1— estimate +T 0 =20 ms<T budget , and the data packet is transmitted normally.", "[0052] In the second operation, if the transmitter side receives and processes feedback information of a transmission failure after elapsing of a 12 ms delay (i.e., a round-trip transmission period of time T RTT 1 occupied for the first transmission, where T RTT 1 =12 ms), then the data packet is queued for the next transmission.", "[0053] In the third operation, if the data packet is to be retransmitted, and a period of time during which the data packet waits in the buffer since the first round-trip transmission ends until the second round-trip transmission is initiated is denoted as T wait 1 , where T wait 1 =20 ms, then the stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 =52 ms;", "a predicated period of time for the second transmission of the data packet T trans 2— estimate is determined, where T trans 2— estimate =5 ms.", "Due to the fact that T 0 +T wait 1 +T RTT 1 +T trans 2— estimate =57 ms<T budget , the data packet is transmitted normally.", "[0054] In the fourth operation, if the transmitter side receives and processes feedback information of a transmission failure after elapsing of a 11 ms delay (i.e., a round-trip transmission period of time T RTT 2 occupied for the second transmission, where T RTT 2 =11 ms), then the data packet is queued for the next transmission.", "[0055] In the fifth operation, if the data packet is to be retransmitted, and a period of time during which the data packet waits in the buffer since the second round-trip transmission ends until the third round-trip transmission is initiated is denoted as T wait 2 , where T wait 2 =10 ms, then in analogy to the third operation, the stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 =73 ms;", "a predicated period of time for the third transmission of the data packet T trans 3— estimate is determined, where T trans 3— estimate =5 ms.", "Due to the fact that T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T trans 3— estimate =78 ms<T budget , the data packet is transmitted normally.", "[0056] In the sixth operation, the total stay period of time during which the data packet stays in the buffer may be drawn as T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T RTT 3 =84 ms>T budget after elapsing of a 11 ms delay again (i.e., a round-trip transmission period of time T RTT 3 occupied for the third transmission, where T RTT 3 =11 ms), and the data packet is discarded when it is arranged in the first place of the buffer again, regardless of whether the third transmission succeeds or fails.", "[0057] In the present second embodiment, if it a period of time for transmission of a data packet is equal to a period of time for the data packet to travel from a transmitter side to a receiver side+a period of time occupied for the receiver side to process the data packet+a transmission period of time occupied for the receiver side to transmit feedback information to the transmitter side and the feedback information to reach the transmitter side+a period of time for the transmitter side to process the received feedback information, then in the foregoing fifth operation, the determined predicated period of time for the third transmission of the data packet may possibly be drawn as T trans 3— estimate =11 ms, and in this case, the third transmission is not performed any longer and the data packet is discarded directly due to the fact that T 0 +T wait 1 +T RTT 1 +T wait 2 +T RTT 2 +T trans 3— estimate =84 ms>T budget .", "[0058] In view of the above operations, if a data packet is to be transmitted, the sum of a stay period of time at the transmitter side and a predicated transmission period of time of the data packet may be denoted with formula (1) suitable for that the data packet is to be transmitted for the first time, and formula (2) suitable for that the data packet is to be retransmitted, [0000] T = T 0 + T trans_estimate ( 1 ) T = T 0 + ∑ i = 1 M   T wait i + ∑ i = 1 M  T RTT i + T trans_estimate ( 2 ) [0059] T denotes the sum of the wait period of time occupied for the data packet and the predicated transmission period of time thereof, T 0 denotes the period of time during which the data packet waits for the first transmission in the buffer, T trans — estimate denotes the predicated transmission time required for the ongoing transmission of the data packet [0000] ∑ i = 1 M   T wait i [0000] denotes the sum of periods of time for the data packet in waiting for being scheduled from the ending of the former of every two adjacent round-trip transmissions to the starting of the latter of the two adjacent round-trip transmissions among performed round-trip transmission processes and the ongoing round-trip transmission process (M denotes the number of times that the data packet has been transmitted);", "and [0000] ∑ i = 1 M  T RTT i [0000] denotes the sum of round-trip transmission periods of time occupied for respective transmissions (the round-trip transmission period of time is equal to a sum of a period of time for transmission of the data packet from the transmitter side to the receiver side, a period of time occupied for the receiver side to process the data packet, a period of time occupied for the receiver side to transmit feedback information and a period of time for the transmitter side to process the feedback information).", "[0060] The method according to an embodiment of the invention may be applied in a simulation experiment, for example, in a system of Time Division duplex-Synchronous Code Division Multiple Access High Speed Uplink Packet Access (TD-SCDMA HSUPA), and for a VoIP service in use, where the maximum delay of an air interface tolerable to the system is 80 ms, a round-trip transmission period of time is 15 ms, and the largest number of transmissions of the system is four (i.e., the number of retransmissions is three), in this case a simulation result is as illustrated schematically in FIG. 3 .", "As may be apparent from FIG. 3 , in the event of a traditional solution using the largest number of retransmissions of three, a reserved period of time required for the largest number of transmissions is 60 ms, and the remaining 20 ms is taken as a packet discard threshold, therefore this solution can support at most only three users per sector.", "In contrast, the solution in the present embodiment eliminates the need of reserving a period of time required for the largest number of transmissions and can enable flexible control in response to an actual network status to support at most five users per sector, thereby improving a capacity of the system by 66%.", "[0061] A third embodiment of the invention provides a data processing device corresponding to the data processing method in the first embodiment with a structure as illustrated schematically in FIG. 4 , which includes a predicated transmission period of time determination module 11 , a stay period of time determination module 12 , a calculation module 13 and a processing module 14 , where the predicated transmission period of time determination module 11 is configured to determine a predicated transmission period of time required for transmitting a data packet for transmission;", "the stay period of time determination module 12 is configured to determine a stay period of time during which the data packet for transmission stays in a buffer;", "the calculation module 13 is configured to calculate the sum of the predicated transmission period of time and the stay period of time;", "and the processing module 14 is configured to discard the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time exceeds a preset delay of an air interface.", "[0062] Moreover, the processing module 14 may further be configured to transmit the data packet when a result of the calculating indicates that the sum of the predicated transmission period of time and the stay period of time does not exceed the preset delay of an air interface.", "[0063] Moreover, the device further includes a transmission counting module 15 configured to increment a recorded number of transmissions of the data packet by one after the processing module 14 has transmitted the data packet.", "[0064] The device further includes a transmission number determination module 16 configured to trigger the predicated transmission period of time determination module 11 and the stay period of time determination module 12 upon determining that the number of transmissions of the data packet for transmission does not exceed the largest number of transmissions.", "[0065] With the method and device according to the embodiments of the invention, times for packet discarding for data packets of different users and different data packets of the same user can be adjusted dynamically in response to an actual condition of a transmission system to make full use of a service delay budget, reduce a packet loss rate in a buffer at a transmitter side, improve a quality of service, as well as improve the capacity of the system in which a service with a strict delay requirement is borne.", "Moreover, when an embodiment of the invention is applied in a system of a High Speed Downlink Packet Access (HSDPA), a protocol of the system is subject to minor modifications, and good performance of the system can be achieved with simple operations in the event that the system operates normally.", "[0066] Evidently, those skilled in the art can make various modifications and variations to the invention without departing from the scope of the invention.", "Thus, the invention is also intended to encompass these modifications and variations of the invention provided these modifications and variations come into the scope of the appended claims and their technical equivalents." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a delay-locked loop for data recovery, and more particularly, for recovering the Manchester coded digital data having two kinds of fixed length of "1" and "0" to its original data. 2. Description of the Related Art FIG. 1 schematically illustrates coding of a Manchester code, while FIG. 2 gives a sample of the coded result. For Manchester code, there are only two kinds of fixed lengths for continuous "1" and "0". For example, the two lengths of Ether Net application having a transferring speed of 10 Mbps are 50 and 100 ns. The disadvantages when using the typical phase-locked loop to recover the clock/data are that: (1) since the signal contains different length of "0" and "1" which do not have a fixed period, the phase-locked loop can not be stabilized easily; (2) the phase-locked loop adjusts the frequency of recovering clock to synchronize the signals, which also causes the accumulation of phase errors from one period to the next period; and (3) the loop filter of a phase-locked loop is a RC circuit which results in the resistor and capacitor often occupying most of the area during the manufacture of a semiconductor device. In addition, because each port requires a respective set of phase-locked loop during a multiport application, the increase of area is directly proportional to the increase of number of ports. SUMMARY OF THE INVENTION Therefore, the object of the invention is to provide a delay-locked loop which recovers the Manchester coded digital data having certain fixed length of "1" and "0" to its original data. Some advantages are that (1) the loop can be easily stabilized; (2) the phase errors do not accumulate; (3) the area of chip is small; and (4) the increase of area of chip is not directly proportional to the increase of number of ports during multiport application. The delay-locked loop of the invention, which transforms the coded digital data having two kinds of fixed length: T1, 2T1 of "1" and "0" into its original data, includes an encoder, a first, second and third phased delay device, a phrase/frequency detector, a charge pumr and loop filter. The encoder receives a clock signal CK and generates two signals φ 0 and φ r which have the same periods. Both of the signals simultaneously change from "1" into "0" within one period. After a time t1, the signal φ 0 changes from "0" into "1" and after another time t2=, the signal φ r changes from "0" into "1". While after yet another time t3 both signals simultaneously change from "1" into "0"; The first phase-delayed device receives the signal φ 0 from the encoder and the control signal Vc, and outputs a signal φ 4 whose period is identical to the signal φ 0 . When the signal φ 0 changes from "1" into "0", the signal φ 4 also changes from "1" to "0" simultaneously. When the signal φ 0 changes from "0" into "1" and keeps in "1" for a time t2, the signal φ 4 changes from "0" into "1"; The second phase-delayed device receives the data DATA from the outside and the control signal Vc, and outputs signals φ 1 + , φ 2 + , φ 3 + , φ 4 + . The relationship between these φ i + S (1≦i≦4k) and the DATA is as follows: (1) when DATA changes from "1" nto "0", the φ i + (1≦i≦4 changes from "1"to "0" simultaneously; (2) when DATA changes from "0" to "1" and keeps in "1" for a time i x (T1 /2), the φ i + (1≦i≦4 changes from "0" to "1"; The third phase-delayed device receives the complement of data DATA from the outside and the control signal Vc, and outputting signals φ 1 - , φ 2 - , φ 3 - , φ 4 - . The relationship between these φ i - (1≦i≦4 and the DATA is as follows: (1) when DATA changes from "1" to "0", the φ i - S (1≦i≦4 change from "1" into "0" simultaneously; (2) when the complement of DATA changes from "0" into "1" and keeps in "1" for a time ix (T1/2), the φ i - (1≦i≦4 change from "0" into "1"; The phase/frequency detector receives the signal φ r from the encoder and the signal φ 4 from the first phase-delayed device, and outputs the signals up and dn as follows: (1) when the phase of signal φ r is ahead of the phase of signal φ 4 up is "1" and dn is "0"; (2) when the phase of signal φ r is behind the phase of signal φ 4 up is "0" and dn is "1". The charge pump and loop filter receive the signals up and dn from the phase/frequency detector and output control signal Vc to the first, second, and third phase-delayed devices. Therefore, when up is "1" and dn is "0", the level of the control signal Vc and current I 1 ,(I 1 =I 2 =I 3 =I 4 ) is increased to advance the phases of φ 4 , φ i + , and φ i - (1≦i≦4). When up is "0" and dn is "1", the value of the control signal Vc and the value of current I 1 (I 1 =I 2 =I 3 =I 4 ) is decreased to delay the phases of φ 4 , φ i + , and φ i - (1≦i≦4). Therefore, the phases of these signals φ i + and φ i - (1≦i≦4) can be accurately locked in the needed position after the whole loop is stabilized. The Manchester coded digital data can be recovered by using said φ i + and φ i - (1≦i≦4) as follows: (1) if φ 2i-1 + appears and φ 2i+1 + (i= 1,2) does not, the digital data being judged to be "1" with a length i x T1; (2) if φ 2i-1 - appears and φ 2i+1 - (i=1,2) does not, the digital data is judged to be "0" with a length of I x T1. Therefore, the data DATA is recovered. The detailed features and characteristics of the invention is to be described more clearly with the descriptions of the preferred embodiments in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the encoding procedure of Manchester code. FIG. 2 illustrates that the "1" and "0" of Manchester-coded digital have only two fixed continuous lengths. FIG. 3 is a block diagram of the delay-locked loop according to the invention. FIG. 4 shows the circuit diagram of a preferred embodiment of phase-delayed device 2 shown in FIG. 3, this is also a preferred embodiment of phase-delayed device 3 or 4. FIG. 5A shows the circuit diagram of a preferred embodiment of decoder 1 shown in FIG. 3. FIG. 5B shows the wave forms of different signals according to the decoder circuit shown in FIG. 5A. FIG. 6 shows the circuit diagram of a preferred embodiment of charge pump and loop filter 6 shown in FIG. 3. FIG. 7 shows the clock of different signals shown in FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT When the data to be recovered is a Manchester code, the delay-locked loop according to the invention (FIG. 3) includes: an encoder 1, a phase-delayed device 2, a phase-delayed device 3, a phase-delayed device 4, a phase/frequency detector 5, and a charge pump and loop filter 6. The functions of each component are described in the summary of the invention. The phase of output signal φ 4 of the phase-delayed device 2 falls behind the phase of the signal φ 0 by t 2 =2Ti. The output signals of phase-delayed device 3 are φ 1 + , φ 2 + , φ 3 + , and φ 4 + ; and the output signals of phase-delayed device 4 are φ 1 - , φ 2 - , φ 3 - , and φ 4 - . The phase-delayed device 2, phase-delayed device 3, and phase-delayed device 4 may be formed with the same circuit. FIG. 4 shows the circuit diagram of the preferred embodiment of phase-delayed device 2. The circuit includes four delay units whose structures are identical with two input terminals and one output terminal. The operation of the first delay unit is described below: (1) when signal φ 0 is transformed from "1" into "0", the PMOS transistors Q11, Q21, Q31, and Q41 momentarily change from an OFF state to an ON state, and the nodes N1, N2, N3, and N4 are pulled to high potential, while the complement signals φ 1 , φ 2 , φ 3 , and φ 4 are momentarily changed into "0"; (2) when signal φ 0 changes from "0" into "1", the NMOS transistor Q12 momentarily changes from an OFF state to an ON state. Since the PMOS transistors Q11 is OFF now, the drain current of transistor Q12 is supplied by discharging of capacitor C1. Therefore, the potential of node N1 decreases gradually until the potential is lower than the threshold of inverter D1 and thus changing the signal φ 1 from "0" to "1". Now the NMOS transistor Q22 of the second delay unit momentarily changes form an OFF state to an ON state. Similarly, the third and fourth delay units also have the same operating steps. Since the current 11, 12, 13, and 14 are controlled by the voltage signal Vc, each of the currents has the same value, which makes the time delays caused by these delay units identical. The output φ 4 of the fourth delay unit is the output signal of the phase-delayed device 2. The phase-delayed device 3 and phase-delayed device 4 can also have the same circuit as the phase-delayed device 2. We replace the signal φ 0 with the data DATA or the complement of DATA, and export the outputs of every delay units as the output signals. FIG. 5A shows the circuit diagram of the preferred embodiment of encoder 1, the circuit includes: D flip-flop 11, D flip-flop 12, AND gate 13, and NAND gate 14. The period of clock signal CK is T1, and the signal RESET is used for resetting all settings. The output of the AND gate 13 is used as signal φ r and the output of the NAND gate 14 is used as signal φ 0 . FIG. 5B shows the wave forms of every signal according to the circuit shown in FIG. 5A wherein the relationships between signal φ r and signal φ 0 are described below. When the signal φ 0 changes from "0" to "1", after a time t 2 =2T1, the signal φ r also changes from "0" to "1". There is no limitations between time t1 and t3 wherein t1 is the time interval from when the signal φ 0 changes from "1" to "0" until the the signal φ 0 changes from "0" to "1". T3 is the time interval from when the signal φ r changes from "0" to "1" until the signal φ 0 changes from "1" to "0". According to the embodiment shown in FIG. 5B, t1=t3=T1. FIG. 6 shows the circuit diagram of the preferred embodiment of charge pump and loop filter 6. When up is "1" and dn is "0", Vc increases and when up is "0" and dn is "1", Vc decreases. While both up and dn are "0", Vc remains unchanged. FIG. 7 shows the timing diagram of the signals shown in FIG. 3. The delay-locked loop according to the invention is still immune from a very large phase jitter, e.g., +(0.5 T1-ε) wherein the ε is a small value, while such a serious phase jitter is quite rare. Taken altogether, there are four advantages of the invention: 1. It can be easily stabilized. The wave forms, φ r and φ 4 , are identical. Therefore, it can be stably phase-locked by a typical phase/frequency detector. 2. The phase error does not accumulate. Since the phase delay begins at the rising edge of a signal and ends at the falling edge of a signal, the phase error does not cumulate to the next period. 3. The loop filter requires only one capacitor, which reduces the area of chip. Since the phase error does not accumulate, the RC circuit is not necessary and the area of chip is retrenched. 4. The increase of area of chip is not directly proportional to the increase of number of ports during multiport application. It is not necessary to repeat the whole circuit in each port during multiport application, only the circuit within the dotted frame in FIG. 3 has to be repeated, which greatly reduces the area of chip. The aforesaid preferred embodiments of the invention are used only for illustration purpose rather than for limiting this invention. Variations and modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of this invention is intended to cover the following appended claims.
A delay-locked loop which phase-locks the reference clock of crystal oscillation by certain identical delay units for generating certain precise time-sharing phase signals. These time-sharing phase signals can be utilized to recover the clock/data. The advantages of the invention, when comparing with the typical phase-locked loop, are: (1) it can be easily stabilized; (2) the phase error does not accumulate; (3) the loop filter requires only one capacitor, which reduces the area of chip; (4) no additional loop filter is need in multiport application, which further reduces the area of chip.
Summarize the information, clearly outlining the challenges and proposed solutions.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The invention relates to a delay-locked loop for data recovery, and more particularly, for recovering the Manchester coded digital data having two kinds of fixed length of "1"", "and "0"", "to its original data.", "Description of the Related Art FIG. 1 schematically illustrates coding of a Manchester code, while FIG. 2 gives a sample of the coded result.", "For Manchester code, there are only two kinds of fixed lengths for continuous "1"", "and "0".", "For example, the two lengths of Ether Net application having a transferring speed of 10 Mbps are 50 and 100 ns.", "The disadvantages when using the typical phase-locked loop to recover the clock/data are that: (1) since the signal contains different length of "0"", "and "1"", "which do not have a fixed period, the phase-locked loop can not be stabilized easily;", "(2) the phase-locked loop adjusts the frequency of recovering clock to synchronize the signals, which also causes the accumulation of phase errors from one period to the next period;", "and (3) the loop filter of a phase-locked loop is a RC circuit which results in the resistor and capacitor often occupying most of the area during the manufacture of a semiconductor device.", "In addition, because each port requires a respective set of phase-locked loop during a multiport application, the increase of area is directly proportional to the increase of number of ports.", "SUMMARY OF THE INVENTION Therefore, the object of the invention is to provide a delay-locked loop which recovers the Manchester coded digital data having certain fixed length of "1"", "and "0"", "to its original data.", "Some advantages are that (1) the loop can be easily stabilized;", "(2) the phase errors do not accumulate;", "(3) the area of chip is small;", "and (4) the increase of area of chip is not directly proportional to the increase of number of ports during multiport application.", "The delay-locked loop of the invention, which transforms the coded digital data having two kinds of fixed length: T1, 2T1 of "1"", "and "0"", "into its original data, includes an encoder, a first, second and third phased delay device, a phrase/frequency detector, a charge pumr and loop filter.", "The encoder receives a clock signal CK and generates two signals φ 0 and φ r which have the same periods.", "Both of the signals simultaneously change from "1"", "into "0"", "within one period.", "After a time t1, the signal φ 0 changes from "0"", "into "1"", "and after another time t2=, the signal φ r changes from "0"", "into "1".", "While after yet another time t3 both signals simultaneously change from "1"", "into "0";", "The first phase-delayed device receives the signal φ 0 from the encoder and the control signal Vc, and outputs a signal φ 4 whose period is identical to the signal φ 0 .", "When the signal φ 0 changes from "1"", "into "0", the signal φ 4 also changes from "1"", "to "0"", "simultaneously.", "When the signal φ 0 changes from "0"", "into "1"", "and keeps in "1"", "for a time t2, the signal φ 4 changes from "0"", "into "1";", "The second phase-delayed device receives the data DATA from the outside and the control signal Vc, and outputs signals φ 1 + , φ 2 + , φ 3 + , φ 4 + .", "The relationship between these φ i + S (1≦i≦4k) and the DATA is as follows: (1) when DATA changes from "1"", "nto "0", the φ i + (1≦i≦4 changes from "1"to "0"", "simultaneously;", "(2) when DATA changes from "0"", "to "1"", "and keeps in "1"", "for a time i x (T1 /2), the φ i + (1≦i≦4 changes from "0"", "to "1";", "The third phase-delayed device receives the complement of data DATA from the outside and the control signal Vc, and outputting signals φ 1 - , φ 2 - , φ 3 - , φ 4 - .", "The relationship between these φ i - (1≦i≦4 and the DATA is as follows: (1) when DATA changes from "1"", "to "0", the φ i - S (1≦i≦4 change from "1"", "into "0"", "simultaneously;", "(2) when the complement of DATA changes from "0"", "into "1"", "and keeps in "1"", "for a time ix (T1/2), the φ i - (1≦i≦4 change from "0"", "into "1";", "The phase/frequency detector receives the signal φ r from the encoder and the signal φ 4 from the first phase-delayed device, and outputs the signals up and dn as follows: (1) when the phase of signal φ r is ahead of the phase of signal φ 4 up is "1"", "and dn is "0";", "(2) when the phase of signal φ r is behind the phase of signal φ 4 up is "0"", "and dn is "1".", "The charge pump and loop filter receive the signals up and dn from the phase/frequency detector and output control signal Vc to the first, second, and third phase-delayed devices.", "Therefore, when up is "1"", "and dn is "0", the level of the control signal Vc and current I 1 ,(I 1 =I 2 =I 3 =I 4 ) is increased to advance the phases of φ 4 , φ i + , and φ i - (1≦i≦4).", "When up is "0"", "and dn is "1", the value of the control signal Vc and the value of current I 1 (I 1 =I 2 =I 3 =I 4 ) is decreased to delay the phases of φ 4 , φ i + , and φ i - (1≦i≦4).", "Therefore, the phases of these signals φ i + and φ i - (1≦i≦4) can be accurately locked in the needed position after the whole loop is stabilized.", "The Manchester coded digital data can be recovered by using said φ i + and φ i - (1≦i≦4) as follows: (1) if φ 2i-1 + appears and φ 2i+1 + (i= 1,2) does not, the digital data being judged to be "1"", "with a length i x T1;", "(2) if φ 2i-1 - appears and φ 2i+1 - (i=1,2) does not, the digital data is judged to be "0"", "with a length of I x T1.", "Therefore, the data DATA is recovered.", "The detailed features and characteristics of the invention is to be described more clearly with the descriptions of the preferred embodiments in conjunction with the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the encoding procedure of Manchester code.", "FIG. 2 illustrates that the "1"", "and "0"", "of Manchester-coded digital have only two fixed continuous lengths.", "FIG. 3 is a block diagram of the delay-locked loop according to the invention.", "FIG. 4 shows the circuit diagram of a preferred embodiment of phase-delayed device 2 shown in FIG. 3, this is also a preferred embodiment of phase-delayed device 3 or 4.", "FIG. 5A shows the circuit diagram of a preferred embodiment of decoder 1 shown in FIG. 3. FIG. 5B shows the wave forms of different signals according to the decoder circuit shown in FIG. 5A.", "FIG. 6 shows the circuit diagram of a preferred embodiment of charge pump and loop filter 6 shown in FIG. 3. FIG. 7 shows the clock of different signals shown in FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT When the data to be recovered is a Manchester code, the delay-locked loop according to the invention (FIG.", "3) includes: an encoder 1, a phase-delayed device 2, a phase-delayed device 3, a phase-delayed device 4, a phase/frequency detector 5, and a charge pump and loop filter 6.", "The functions of each component are described in the summary of the invention.", "The phase of output signal φ 4 of the phase-delayed device 2 falls behind the phase of the signal φ 0 by t 2 =2Ti.", "The output signals of phase-delayed device 3 are φ 1 + , φ 2 + , φ 3 + , and φ 4 + ;", "and the output signals of phase-delayed device 4 are φ 1 - , φ 2 - , φ 3 - , and φ 4 - .", "The phase-delayed device 2, phase-delayed device 3, and phase-delayed device 4 may be formed with the same circuit.", "FIG. 4 shows the circuit diagram of the preferred embodiment of phase-delayed device 2.", "The circuit includes four delay units whose structures are identical with two input terminals and one output terminal.", "The operation of the first delay unit is described below: (1) when signal φ 0 is transformed from "1"", "into "0", the PMOS transistors Q11, Q21, Q31, and Q41 momentarily change from an OFF state to an ON state, and the nodes N1, N2, N3, and N4 are pulled to high potential, while the complement signals φ 1 , φ 2 , φ 3 , and φ 4 are momentarily changed into "0";", "(2) when signal φ 0 changes from "0"", "into "1", the NMOS transistor Q12 momentarily changes from an OFF state to an ON state.", "Since the PMOS transistors Q11 is OFF now, the drain current of transistor Q12 is supplied by discharging of capacitor C1.", "Therefore, the potential of node N1 decreases gradually until the potential is lower than the threshold of inverter D1 and thus changing the signal φ 1 from "0"", "to "1".", "Now the NMOS transistor Q22 of the second delay unit momentarily changes form an OFF state to an ON state.", "Similarly, the third and fourth delay units also have the same operating steps.", "Since the current 11, 12, 13, and 14 are controlled by the voltage signal Vc, each of the currents has the same value, which makes the time delays caused by these delay units identical.", "The output φ 4 of the fourth delay unit is the output signal of the phase-delayed device 2.", "The phase-delayed device 3 and phase-delayed device 4 can also have the same circuit as the phase-delayed device 2.", "We replace the signal φ 0 with the data DATA or the complement of DATA, and export the outputs of every delay units as the output signals.", "FIG. 5A shows the circuit diagram of the preferred embodiment of encoder 1, the circuit includes: D flip-flop 11, D flip-flop 12, AND gate 13, and NAND gate 14.", "The period of clock signal CK is T1, and the signal RESET is used for resetting all settings.", "The output of the AND gate 13 is used as signal φ r and the output of the NAND gate 14 is used as signal φ 0 .", "FIG. 5B shows the wave forms of every signal according to the circuit shown in FIG. 5A wherein the relationships between signal φ r and signal φ 0 are described below.", "When the signal φ 0 changes from "0"", "to "1", after a time t 2 =2T1, the signal φ r also changes from "0"", "to "1".", "There is no limitations between time t1 and t3 wherein t1 is the time interval from when the signal φ 0 changes from "1"", "to "0"", "until the the signal φ 0 changes from "0"", "to "1".", "T3 is the time interval from when the signal φ r changes from "0"", "to "1"", "until the signal φ 0 changes from "1"", "to "0".", "According to the embodiment shown in FIG. 5B, t1=t3=T1.", "FIG. 6 shows the circuit diagram of the preferred embodiment of charge pump and loop filter 6.", "When up is "1"", "and dn is "0", Vc increases and when up is "0"", "and dn is "1", Vc decreases.", "While both up and dn are "0", Vc remains unchanged.", "FIG. 7 shows the timing diagram of the signals shown in FIG. 3. The delay-locked loop according to the invention is still immune from a very large phase jitter, e.g., +(0.5 T1-ε) wherein the ε is a small value, while such a serious phase jitter is quite rare.", "Taken altogether, there are four advantages of the invention: 1.", "It can be easily stabilized.", "The wave forms, φ r and φ 4 , are identical.", "Therefore, it can be stably phase-locked by a typical phase/frequency detector.", "The phase error does not accumulate.", "Since the phase delay begins at the rising edge of a signal and ends at the falling edge of a signal, the phase error does not cumulate to the next period.", "The loop filter requires only one capacitor, which reduces the area of chip.", "Since the phase error does not accumulate, the RC circuit is not necessary and the area of chip is retrenched.", "The increase of area of chip is not directly proportional to the increase of number of ports during multiport application.", "It is not necessary to repeat the whole circuit in each port during multiport application, only the circuit within the dotted frame in FIG. 3 has to be repeated, which greatly reduces the area of chip.", "The aforesaid preferred embodiments of the invention are used only for illustration purpose rather than for limiting this invention.", "Variations and modifications may be made without departing from the spirit and scope of the invention.", "Therefore, the scope of this invention is intended to cover the following appended claims." ]
BACKGROUND OF THE INVENTION Loading ramps to provide a bridge between a loading dock and the bed of a vehicle to be loaded or unloaded .[.is.]. .Iadd.are .Iaddend.a well developed art. In its basic form the prior art apparatus includes a platform or ramp which is automatically raised by release of a spring, the actuation of a hydraulic motor, the release or falling of a weight or perhaps a motor designed to raise the ramp by gear connections. Ordinarily, the pivotable ramp is mounted on a frame built into a pit in the loading dock. Traditionally, the upper surface of the ramp will be coplanar with the surface of the loading .[.deck.]. .Iadd.dock.Iaddend.. The rear edge of the ramp is pivoted about an axis at or near the level of the loading dock and the forward end of the .[.deck.]. .Iadd.ramp .Iaddend.includes a lip which is pivotable and projectable to lie on the bed of the vehicle to be serviced. By whatever means, the ramp will be raised and then the workman will walk out on the raised ramp. Some automatic or semi-automatic mechanical structure comes into play to project the lip progressively as the ramp itself is "walked down" on some newer models, but for the most part, the lip will be projected by some mechanical apparatus on the upswing. At some stage during the walk down process the lip projecting means is slowly released by the projecting means and a lip lock holds the lip in projected position. The lock is usually released by gravity or springs when the lip engages the truck bed. SUMMARY OF THE INVENTION Conventional apparatus is used herein to a certain extent and it includes a ramp mounted on a frame designed to fit into a loading dock pit designed to house a dock leveling apparatus. The ramp is pivotally attached to the rearmost portion of the frame and designed to be coplanar at that point with the loading dock. Any conventional apparatus may be used to raise the ramp. It is clear that the apparatus of this invention could be operated without a pit. For example, the leveler could be mounted in front of or on top of the dock. Mechanical means for projecting the lip during the walk down of the ramp include telescoping tubes which together form a straight arm pivoted from both ends with one end being pivoted from a lug mounted on the lip and the other end being pivoted from a short bar. The short bar is in turn pivoted on its other end from the frame. Intermediate the ends of the short bar is a projection which limits the forward and downward pivoting of the bar and arm. A bolt in the outer portion of the projection allows adjustment of the degree of pivoting for reasons which will be explained subsequently. A lip lock is designed to be mounted with one end pivoted from a lug mounted on the under surface of the lip. The other end of the lip lock structure is slidingly supported by a pin projecting from lug means on the underside of the ramp. During the walk down period, at the time the lip projecting means has projected the lip to approximately the needed extension, the pin slides into a locking slot .Iadd.or notch .Iaddend.in the lip lock apparatus which prevents the downward rotation of the lip. At a point in time shortly after the latching by the lip lock apparatus, the lip projecting means is released and the sole lip support is the lip lock means which will retain the lip in its outwardly projected position as the ramp continues to descend until one of two things happens. Either the lip will engage the bed of a truck which will in itself rotate the lip to a position approximately parallel with the plane of the ramp or the ramp will continue to descend below the dock level of the loading dock until the lip lock means reaches an upwardly extending projection mounted on the lower portion of the mounting frame which will release the lip lock means and allow the lip to swing downward by gravity. The many bars, levers, arms, etc. involved in the lip projecting and locking units are all related lengths. The adjusting means associated with the short bar of the lip projecting means allows much looser manufacturing tolerances as to the lengths, bolt holes, grooves, etc. because the manufacturing differences can be .[.accomodated.]. .Iadd.accommodated. .Iaddend. Having thus given a summary of the invention, a brief description of the drawings and a detailed description of the preferred embodiment follow and objects of this invention will become clear from a reading of the description of the preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the dock leveling apparatus of this invention. FIG. 2 is a fragmentary sectional view of the apparatus of FIG. 1 in closed position taken along line 2--2 of FIG. 1. FIGS. 2-5 show sequential operations, all on the same 2--2 section line. FIG. 3 is a fragmentary sectional view similar to FIG. 2 but with the ramp raised to its highest position for walk down. FIG. 4 is a fragmentary sectional view similar to FIG. 3 but after walk down has started, at the time the lip lock has engaged and just prior to the time the lip projecting means releases. FIG. 5 is a fragmentary sectional view showing the apparatus in operative position with the lip in engagement with the bed of the truck to be serviced. FIG. 6 is another fragmentary sectional view of the apparatus of FIG. 1 in closed position taken along line 6--6. FIG. 6-9 are all taken along the same section line 6--6 to show the same sequence illustrated in FIGS. 2-5. FIG. 10 is an exploded view of the lip dock apparatus of this invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Dock leveling apparatus indicated generally at 10 is designed to be mounted in a pit 11 formed at one edge of the loading dock, however, in some instances the apparatus may be mounted as a dock extension projecting beyond the edge of a loading dock or on top of an existing dock. But it is the intention of this invention that the deck or ramp 12 mounted on frame 14 be pivoted about an axis 16 near or just below the upper planer surface 18 of the loading dock 20 except for those cases where the leveler is mounted on top of the dock. In this instance, a spring 22 is shown biasing the ramp 12 upwardly in combination with a lever arm 24 and rollers 26 which may roll on the underside of the ramp or between the beams 28. While spring biasing means 22 is illustrated, it is clear that hydraulic means might be used with a hydraulic motor, piston etc. as would be clear to those having ordinary skill in the art. In the normal course of events.Iadd., .Iaddend.the ramp 12 will be in the down position generally as indicated in FIGS. 2 and 6 to provide a level surface for cross traffic along the loading dock.[.,.]. .Iadd.and .Iaddend.it will be held down in horizontal position against the upward bias of spring 22 by a hold down 30. No particular description of hold down 30 appears necessary because it provides no part of the novelty of this invention. It is merely a ratchet and pawl type arrangement conventional in many of the dock levelers now on the market and well known in the industry. A lip 32 is mounted on the front portion of the ramp and is pivoted about an axis 34 of conventional hinge means. However, it will be observed that the deck 12 extends forwardly at 35 beyond the edge of the hinge means and it serves the very useful function of preventing falling debris such as sticks, bolts, etc. from fouling the hinge. Additionally, rain and snow often form freezing blocks of ice in exposed hinge areas and inhibit the free swinging operation necessary in outside operation during the winter period. The forward extension 35 of the deck 12 serves in large measure to prevent the ice formation and other types of fouling of the hinge area. A lip projecting arm 36 shown at the left side of FIG. 1 and in FIGS. 6-9 consists of telescoping tubes 38 and 40 which are biased together against elongation by spring means 42. The reason for the extensible arm .[.38.]. .Iadd.36 .Iaddend.is to allow some play in the peak height of the ramp 12. With a rigid arm .[.38.]. .Iadd.36.Iaddend. , rather close tolerances are necessary in adjustment of the spring 22 and some sort of stop means is usually required on the lever arm 24. With the extensible arm .[.38.]. .Iadd.36 .Iaddend.as designed herein the tolerances can be relatively ignored and the springs 42 will hold the telescopic tubes 38 and 40 together without any difficulty. Lug means 44 project from the inside surface of the lip 32 and one end of arm 36 is pivoted therefrom. The other end of the arm 36 is pivoted from a short bar 46 which in turn is pivoted from the frame 14. The pivot point between the bar 46 and arm 36 forms a knuckle joint 48 having a particular function which will be described in more detail in the description of the operation of the invention. Intermediate the ends of the bar 46 is a projection indicated generally at 50 comprising a sleeve 52 into which is threaded a bolt 54. The purpose of the projection 50 is to limit the rotation of the knuckle joint in a forward direction. The head of bolt 54 comes into contact with the frame 14 or some other substrate and this controls the point at which the lip projecting arm 36 will pass the equilibrium point with the bar 46 and kick over to the release position. The reason for the desire for the control will be explained subsequently. Observing FIGS. 10 and .[.2-6.]..Iadd.2-5.Iaddend., the lip lock apparatus 56 includes a pair of parallel plates 58 which are welded together in parallel position but spaced apart by spacers 60. Spacers 60 are of greater width than .Iadd.a .Iaddend.block 62 .Iadd.interposed between the plates 58 .Iaddend.and thus block 62 may slide longitudinally in the space between the plates 58. Bolts 64 are welded to each end of block 62 and .[.the.]. .Iadd.an .Iaddend.elongated shallow U-shaped bracket 66 .[.which.]. .Iadd.is secured to the bottom of the block and .Iaddend.serves to bear against the underside of plates 58 during the sliding motion of the block 62. A cover plate 68 .Iadd.positioned on the top of the block 62 and secured thereto by the bolts 64 .Iaddend.serves a similar function on the top of the plates 58. The bracket 66 .[.is.]. .Iadd.and cover plate 68 are .Iaddend.biased .[.upward.]. into contact with .[.the.]. .Iadd.respective .Iaddend.lower .Iadd.and upper .Iaddend.portions of the plates 58 by spring means 70 which circumscribe the threaded upper portion of bolts 64 and which are compressed by nuts 72. The forward ends of plates 58 are pivotally supported .[.in.]. .Iadd.between downwardly projecting .Iaddend.lugs 74 .Iadd.on the lip 32 .Iaddend.and the rear portion is slidably supported on a pin 76 projecting between downwardly extending lugs 78 on the underside of the ramp 12. The pin projects through the space between the .Iadd.bottom of the block 62 and under the .Iaddend.bracket 66 and the lower surface of the plates 58. For convenience in FIGS. 2-5.Iadd., .Iaddend.the nearer .Iadd.of .Iaddend.the .[.lug.]. .Iadd.lugs .Iaddend. 78 is not illustrated to better show the relative sequential movement of the pin, bracket and plates. .[.Spring means 70 hold the bracket 66 stationary on the bottom edges of plates 58 except for movement forced by pin 76..]. A .Iadd.downwardly opening .Iaddend.groove 80 is formed in the underside of the block 62 .Iadd.to receive the pin 76 .Iaddend.and .Iadd.downwardly opening .Iaddend.notches 82 are formed on the underside of plates 58. The notches 82 .[.being coaxial and axis of the notches and the axis of the groove 80 are parallel with.]. .Iadd.in the two plates 58 are longitudinally aligned to cooperatively receive the pin 76 and, at one point in the relative movement of the plates 58 and block 62, these notches will align with the groove 80 for cooperative and concurrent receipt of .Iaddend.the pin 76. The pin 76 is designed to float within the shallow U-shaped bracket 66 and accordingly, the depth of the bracket 66 .Iadd.with respect to the bottom of the block 62 .Iaddend.is greater than the diameter of the pin 76. The functions of the notches 82 and the groove 80 are to receive the pin 76 in locking engagement such that the weight of the lip 32 pressing against plates 58 through lugs 74 will not cam the pin 76 out of the .[.slots.]. .Iadd.bracket groove 80 by means of the notches .Iaddend.82 and back into the U-shaped bracket 66. Accordingly, it is necessary that the depth of the groove .[.80.]. .Iadd.76 .Iaddend.and notches 82 be greater than the radius of the pin 80. To insure that the pin will not be cammed out of the notches the angle of the camming pressure should be at least 90°.Iadd., that is, the forward edge surface should be perpendicular to the longitudinal axis of the plates 58. .Iaddend. In operation.Iadd., .Iaddend.a workman will cause the ramp 12 to be raised by pulling the chain 84 which releases the ramp hold down 30 and allows the spring 22 to .[.bias.]. .Iadd.swing or pivot .Iaddend.the ramp upward .Iadd.to a fully raised position.Iaddend.. He will then walk out on the ramp 12 .[.to force it down.]. .Iadd.and his weight will then cause the ramp to swing downwardly.Iaddend.. If for some reason.Iadd., .Iaddend.he does not wish the lip 32 to project, he will .Iadd.first .Iaddend.pull the chain 86 which will force the knuckle joint 48 over .Iadd.center to place the arm 36 and bar 46 in a relative position as in FIG. 9 where the arm 36 will be ineffective .Iaddend.and will not project the lip 32 and the ramp will simply descend .[.to.]. .Iadd.with the lip 32 hanging downward in .Iaddend.the position shown in FIG. .[.2.]. .Iadd.3.Iaddend. . However, as a general rule.Iadd., .Iaddend.the desire will be to project the lip. Accordingly, as the weight of the workman causes the ramp to descend.Iadd., .Iaddend.the arm 36, acting through lugs 44, will cause the lip 32 to .Iadd.swing upwardly with respect to the ramp 12 and .Iaddend.project outward as the ramp 12 pivots downward .Iadd.as sequentially shown in FIGS. 6-9.Iaddend.. The arm 36 will continue to project the lip until just after the bar 46 and arm 36 become a straight line at which time the knuckle joint .[.46 will.]. .Iadd.48 passes through center permitting the arm and bar to .Iaddend.bend .Iadd.as shown in FIG. 9 .Iaddend.and the force to project the lip 32 will be released. Observing FIGS. 2-5.Iadd., .Iaddend.it will be seen that at the rest position .Iadd.of FIG. 2, .Iaddend.with the lip 32 approximately perpendicular to .[.the.]. .Iadd.a .Iaddend.ramp 12 and behind the keeper 88 .Iadd.secured to the frame 14.Iaddend., the pin 76 is at the forwardmost portion of the U-shaped bracket 66. Similarly, in FIG. 3 with the ramp raised to its maximum, the pin 76 is still forward because the lip 32 is still at an angle perpendicular to the ramp. As the lip .[.projector.]. .Iadd.projection arm .Iaddend.36 begins to project .Iadd.or swing .Iaddend.the lip .Iadd.upwardly .Iaddend.during the walk down, the plates 58 will be pulled forward by the lugs 74 and the pin 76 being .Iadd.held .Iaddend.stationary .Iadd.by its supporting lugs 78 .Iaddend.will slide to the rear of the U-shaped bracket to a point most remote from the lip .Iadd.since the block 66 is carried with the forwardly moving plates 58 through frictional clamping engagement of the bracket 66 and cover plate 68 with the two plates 58.Iaddend.. At that point the bracket will .Iadd.be restrained against further movement with the plates 58 and will .Iaddend.begin to slide .Iadd.along the plates. This movement continues .Iaddend.until the .[.pin pushes the bracket to a point where the upwardly opening U-shape moves under the.]. notches 82 .Iadd.align with the groove 80 which was previously aligned with the pin 76.Iaddend.. The weight of the apparatus 56 .Iadd.then .Iaddend.causes it to fall such that the pin .Iadd.76 .Iaddend.moves into the .Iadd.aligned groove 80 and .Iaddend.notches .Iadd.82 as shown in FIG. 4.Iaddend.. At this point in time or slightly thereafter, the lip projector is designed to release as the knuckle joint 48 passes equilibrium and flips over. The bolt 54 should be adjusted to provide that the knuckle joint 48 will not flip over until the pin 76 is engaged in the .[.slots.]. .Iadd.aligned groove 80 and notches .Iaddend.82. Thereby, lip lock apparatus 56 will then hold the lip 32 in projected position until the lip engages the bed of a truck or other vehicle .Iadd.90 .Iaddend.to be serviced. With the lip .Iadd.32 engaging the bed of the truck .Iadd.90 as shown in FIG. 5, .Iaddend.the ramp .Iadd.12 .Iaddend.will continue to descend and the lip will be .Iadd.further .Iaddend.pivoted .Iadd.or projected .Iaddend.to a position near parallel with the ramp. During this sequence the rear sloping .Iadd.edge .Iaddend.surface of the .[.slot.]. .Iadd.notches .Iaddend.82 will cam the pin .Iadd.76 relatively downward and .Iaddend.out of .[.slot.]. .Iadd.notches .Iaddend.82 and .Iadd.the block groove 80 and .Iaddend.back into the U-shaped bracket 66 as the plates 58 are pulled even further forward .Iadd.and thus unlatches the lip lock apparatus.Iaddend.. As the .[.pin moves back, it will force.]. .Iadd.plates 58 move relatively forward, .Iaddend.the block 62 .[.to the rear by pressing against the rear surface of the groove 80 and.]. .Iadd.will become positioned further rearward on the plates when, .Iaddend. at the full extension of the lip, the block will be almost to the rear of the plates 58 as shown in FIG. 5. .Iadd.It will be noted here that the plates 58, except when relatively positioned to align the notches 82 with the groove 80 and pin 76, will be supported on the pin 76 and will be free to slide on top of the pin. .Iaddend. When the truck .Iadd.90 .Iaddend.pulls away and the lip .Iadd.32 .Iaddend.is .[.released.]. .Iadd.thereby freed .Iaddend.to fall to the perpendicular position, .[.the pin will first move to the forward portion of the bracket 66 before it begins to drive the bracket forward. With the pin in the forward position of the bracket 66 it cannot slide into notches 82 because the block 62 at the forward portion of the bracket 66 prevents such vertical movement, groove 80 is not aligned with the pin, note particularly FIG. 10..]. .Iadd.with respect to the ramp 12, it will be seen that the lip lock apparatus 56 remains unlatched and ineffective and thus permit the lip to pivot downwardly. As the lip 32 pivots downwardly, the plates 58 will slide rearwardly along and be supported on the pin 76. During initial rearward movement of the plates 58, the block 62 will be carried rearwardly therewith through the frictional clamping engagement of the bracket 66 and cover plate 68. However, the block 62 will be restrained against further rearward movement when the pin 76 reaches the forward end of the bracket 66. Continued rearward movement of the plates 58 will result in the notches 82 moving into alignment with the pin 76 but the plates 58 will not drop because the groove 80 in the block 62 is not concurrently aligned therewith. The block 62 thus supports the plates 58 for continued rearward movement as the block is supported on the pin 76 and the plates are then supported on the bracket 66 carried by the block. Thus, the plates 58 may continue their rearward movement thereby permitting the lip to continue pivoting to its full down position. .Iaddend. A lip lock release means is provided for those occasions where the lip .Iadd.32 .Iaddend.is projected and locked into place but then there is some reason to release the lip without having engaged the bed of a truck or there is no truck at the dock. This release means is provided in the form of a bolt 92 projecting upward from the frame 14. When the ramp descends below the level of the surrounding dock.Iadd., .Iaddend.the lower surface of the bracket 66 will engage the top of the bolt 92. This will push the plates 58 .Iadd.and block 62 .Iaddend.upward and disengage the pin 76 from the .[.slots.]. .Iadd.groove 80 and notches .Iaddend.82. .[.at which time.]. .Iadd.This unlatches the lock apparatus 56 as previously described and .Iaddend.the lip 32 will fall by gravity to its pendant position. Having thus described the invention in its preferred embodiment, it will be clear to those having ordinary skill in the art that obvious modifications may be made without departing from the spirit of the invention. Additionally, the language used to describe the invention is not considered limiting. Rather it is intended that the only limitations on the scope of the invention be as set out in the appended claims.
A loading dock leveling apparatus including a ramp pivotable about its rear end and having a pivotable lip on its forward end. Apparatus is provided for projecting the lip outwardly after the ramp is raised beginning when the ramp is walked down to provide that the lip will engage the bed of a vehicle to be loaded or unloaded. The projecting apparatus includes a knuckle joint which pivots to projecting position on the ramp upswing and which is subsequently pivoted by a lever to release the projecting apparatus during the walk down but before the ramp descends to the highest serviceable vehicle level. A lip lock is provided for holding the lip in its projected position until the lip rests on the bed of the vehicle to be unloaded or until the ramp passes well below dock level and the lip lock is disengaged by a lip lock release.
Identify and summarize the most critical technical features from the given patent document.
[ "BACKGROUND OF THE INVENTION Loading ramps to provide a bridge between a loading dock and the bed of a vehicle to be loaded or unloaded .", "is.", "Iadd.", "are .", "Iaddend.", "a well developed art.", "In its basic form the prior art apparatus includes a platform or ramp which is automatically raised by release of a spring, the actuation of a hydraulic motor, the release or falling of a weight or perhaps a motor designed to raise the ramp by gear connections.", "Ordinarily, the pivotable ramp is mounted on a frame built into a pit in the loading dock.", "Traditionally, the upper surface of the ramp will be coplanar with the surface of the loading .", "deck.", "Iadd.", "dock.", "Iaddend..", "The rear edge of the ramp is pivoted about an axis at or near the level of the loading dock and the forward end of the .", "deck.", "Iadd.", "ramp .", "Iaddend.", "includes a lip which is pivotable and projectable to lie on the bed of the vehicle to be serviced.", "By whatever means, the ramp will be raised and then the workman will walk out on the raised ramp.", "Some automatic or semi-automatic mechanical structure comes into play to project the lip progressively as the ramp itself is "walked down"", "on some newer models, but for the most part, the lip will be projected by some mechanical apparatus on the upswing.", "At some stage during the walk down process the lip projecting means is slowly released by the projecting means and a lip lock holds the lip in projected position.", "The lock is usually released by gravity or springs when the lip engages the truck bed.", "SUMMARY OF THE INVENTION Conventional apparatus is used herein to a certain extent and it includes a ramp mounted on a frame designed to fit into a loading dock pit designed to house a dock leveling apparatus.", "The ramp is pivotally attached to the rearmost portion of the frame and designed to be coplanar at that point with the loading dock.", "Any conventional apparatus may be used to raise the ramp.", "It is clear that the apparatus of this invention could be operated without a pit.", "For example, the leveler could be mounted in front of or on top of the dock.", "Mechanical means for projecting the lip during the walk down of the ramp include telescoping tubes which together form a straight arm pivoted from both ends with one end being pivoted from a lug mounted on the lip and the other end being pivoted from a short bar.", "The short bar is in turn pivoted on its other end from the frame.", "Intermediate the ends of the short bar is a projection which limits the forward and downward pivoting of the bar and arm.", "A bolt in the outer portion of the projection allows adjustment of the degree of pivoting for reasons which will be explained subsequently.", "A lip lock is designed to be mounted with one end pivoted from a lug mounted on the under surface of the lip.", "The other end of the lip lock structure is slidingly supported by a pin projecting from lug means on the underside of the ramp.", "During the walk down period, at the time the lip projecting means has projected the lip to approximately the needed extension, the pin slides into a locking slot .", "Iadd.", "or notch .", "Iaddend.", "in the lip lock apparatus which prevents the downward rotation of the lip.", "At a point in time shortly after the latching by the lip lock apparatus, the lip projecting means is released and the sole lip support is the lip lock means which will retain the lip in its outwardly projected position as the ramp continues to descend until one of two things happens.", "Either the lip will engage the bed of a truck which will in itself rotate the lip to a position approximately parallel with the plane of the ramp or the ramp will continue to descend below the dock level of the loading dock until the lip lock means reaches an upwardly extending projection mounted on the lower portion of the mounting frame which will release the lip lock means and allow the lip to swing downward by gravity.", "The many bars, levers, arms, etc.", "involved in the lip projecting and locking units are all related lengths.", "The adjusting means associated with the short bar of the lip projecting means allows much looser manufacturing tolerances as to the lengths, bolt holes, grooves, etc.", "because the manufacturing differences can be .", "accomodated.", "Iadd.", "accommodated.", "Iaddend.", "Having thus given a summary of the invention, a brief description of the drawings and a detailed description of the preferred embodiment follow and objects of this invention will become clear from a reading of the description of the preferred embodiment.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the dock leveling apparatus of this invention.", "FIG. 2 is a fragmentary sectional view of the apparatus of FIG. 1 in closed position taken along line 2--2 of FIG. 1. FIGS. 2-5 show sequential operations, all on the same 2--2 section line.", "FIG. 3 is a fragmentary sectional view similar to FIG. 2 but with the ramp raised to its highest position for walk down.", "FIG. 4 is a fragmentary sectional view similar to FIG. 3 but after walk down has started, at the time the lip lock has engaged and just prior to the time the lip projecting means releases.", "FIG. 5 is a fragmentary sectional view showing the apparatus in operative position with the lip in engagement with the bed of the truck to be serviced.", "FIG. 6 is another fragmentary sectional view of the apparatus of FIG. 1 in closed position taken along line 6--6.", "FIG. 6-9 are all taken along the same section line 6--6 to show the same sequence illustrated in FIGS. 2-5.", "FIG. 10 is an exploded view of the lip dock apparatus of this invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENT Dock leveling apparatus indicated generally at 10 is designed to be mounted in a pit 11 formed at one edge of the loading dock, however, in some instances the apparatus may be mounted as a dock extension projecting beyond the edge of a loading dock or on top of an existing dock.", "But it is the intention of this invention that the deck or ramp 12 mounted on frame 14 be pivoted about an axis 16 near or just below the upper planer surface 18 of the loading dock 20 except for those cases where the leveler is mounted on top of the dock.", "In this instance, a spring 22 is shown biasing the ramp 12 upwardly in combination with a lever arm 24 and rollers 26 which may roll on the underside of the ramp or between the beams 28.", "While spring biasing means 22 is illustrated, it is clear that hydraulic means might be used with a hydraulic motor, piston etc.", "as would be clear to those having ordinary skill in the art.", "In the normal course of events.", "Iadd.", ", .", "Iaddend.", "the ramp 12 will be in the down position generally as indicated in FIGS. 2 and 6 to provide a level surface for cross traffic along the loading dock.", "Iadd.", "and .", "Iaddend.", "it will be held down in horizontal position against the upward bias of spring 22 by a hold down 30.", "No particular description of hold down 30 appears necessary because it provides no part of the novelty of this invention.", "It is merely a ratchet and pawl type arrangement conventional in many of the dock levelers now on the market and well known in the industry.", "A lip 32 is mounted on the front portion of the ramp and is pivoted about an axis 34 of conventional hinge means.", "However, it will be observed that the deck 12 extends forwardly at 35 beyond the edge of the hinge means and it serves the very useful function of preventing falling debris such as sticks, bolts, etc.", "from fouling the hinge.", "Additionally, rain and snow often form freezing blocks of ice in exposed hinge areas and inhibit the free swinging operation necessary in outside operation during the winter period.", "The forward extension 35 of the deck 12 serves in large measure to prevent the ice formation and other types of fouling of the hinge area.", "A lip projecting arm 36 shown at the left side of FIG. 1 and in FIGS. 6-9 consists of telescoping tubes 38 and 40 which are biased together against elongation by spring means 42.", "The reason for the extensible arm .", "[[.", "].38.", "Iadd[.", "].36 .", "Iaddend.", "is to allow some play in the peak height of the ramp 12.", "With a rigid arm .", "[[.", "].38.", "Iadd[.", "].36.", "Iaddend.", ", rather close tolerances are necessary in adjustment of the spring 22 and some sort of stop means is usually required on the lever arm 24.", "With the extensible arm .", "[[.", "].38.", "Iadd[.", "].36 .", "Iaddend.", "as designed herein the tolerances can be relatively ignored and the springs 42 will hold the telescopic tubes 38 and 40 together without any difficulty.", "Lug means 44 project from the inside surface of the lip 32 and one end of arm 36 is pivoted therefrom.", "The other end of the arm 36 is pivoted from a short bar 46 which in turn is pivoted from the frame 14.", "The pivot point between the bar 46 and arm 36 forms a knuckle joint 48 having a particular function which will be described in more detail in the description of the operation of the invention.", "Intermediate the ends of the bar 46 is a projection indicated generally at 50 comprising a sleeve 52 into which is threaded a bolt 54.", "The purpose of the projection 50 is to limit the rotation of the knuckle joint in a forward direction.", "The head of bolt 54 comes into contact with the frame 14 or some other substrate and this controls the point at which the lip projecting arm 36 will pass the equilibrium point with the bar 46 and kick over to the release position.", "The reason for the desire for the control will be explained subsequently.", "Observing FIGS. 10 and .", "[[.", "].2-6.", "]..", "Iadd[.", "].2-5.", "Iaddend.", ", the lip lock apparatus 56 includes a pair of parallel plates 58 which are welded together in parallel position but spaced apart by spacers 60.", "Spacers 60 are of greater width than .", "Iadd.", "a .", "Iaddend.", "block 62 .", "Iadd.", "interposed between the plates 58 .", "Iaddend.", "and thus block 62 may slide longitudinally in the space between the plates 58.", "Bolts 64 are welded to each end of block 62 and .", "the.", "Iadd.", "an .", "Iaddend.", "elongated shallow U-shaped bracket 66 .", "which.", "Iadd.", "is secured to the bottom of the block and .", "Iaddend.", "serves to bear against the underside of plates 58 during the sliding motion of the block 62.", "A cover plate 68 .", "Iadd.", "positioned on the top of the block 62 and secured thereto by the bolts 64 .", "Iaddend.", "serves a similar function on the top of the plates 58.", "The bracket 66 .", "is.", "Iadd.", "and cover plate 68 are .", "Iaddend.", "biased .", "upward.", "into contact with .", "the.", "Iadd.", "respective .", "Iaddend.", "lower .", "Iadd.", "and upper .", "Iaddend.", "portions of the plates 58 by spring means 70 which circumscribe the threaded upper portion of bolts 64 and which are compressed by nuts 72.", "The forward ends of plates 58 are pivotally supported .", "in.", "Iadd.", "between downwardly projecting .", "Iaddend.", "lugs 74 .", "Iadd.", "on the lip 32 .", "Iaddend.", "and the rear portion is slidably supported on a pin 76 projecting between downwardly extending lugs 78 on the underside of the ramp 12.", "The pin projects through the space between the .", "Iadd.", "bottom of the block 62 and under the .", "Iaddend.", "bracket 66 and the lower surface of the plates 58.", "For convenience in FIGS. 2-5.", "Iadd.", ", .", "Iaddend.", "the nearer .", "Iadd.", "of .", "Iaddend.", "the .", "lug.", "Iadd.", "lugs .", "Iaddend.", "78 is not illustrated to better show the relative sequential movement of the pin, bracket and plates.", "Spring means 70 hold the bracket 66 stationary on the bottom edges of plates 58 except for movement forced by pin 76..", "A .", "Iadd.", "downwardly opening .", "Iaddend.", "groove 80 is formed in the underside of the block 62 .", "Iadd.", "to receive the pin 76 .", "Iaddend.", "and .", "Iadd.", "downwardly opening .", "Iaddend.", "notches 82 are formed on the underside of plates 58.", "The notches 82 .", "being coaxial and axis of the notches and the axis of the groove 80 are parallel with.", "Iadd.", "in the two plates 58 are longitudinally aligned to cooperatively receive the pin 76 and, at one point in the relative movement of the plates 58 and block 62, these notches will align with the groove 80 for cooperative and concurrent receipt of .", "Iaddend.", "the pin 76.", "The pin 76 is designed to float within the shallow U-shaped bracket 66 and accordingly, the depth of the bracket 66 .", "Iadd.", "with respect to the bottom of the block 62 .", "Iaddend.", "is greater than the diameter of the pin 76.", "The functions of the notches 82 and the groove 80 are to receive the pin 76 in locking engagement such that the weight of the lip 32 pressing against plates 58 through lugs 74 will not cam the pin 76 out of the .", "slots.", "Iadd.", "bracket groove 80 by means of the notches .", "Iaddend[.", "].82 and back into the U-shaped bracket 66.", "Accordingly, it is necessary that the depth of the groove .", "[[.", "].80.", "Iadd[.", "].76 .", "Iaddend.", "and notches 82 be greater than the radius of the pin 80.", "To insure that the pin will not be cammed out of the notches the angle of the camming pressure should be at least 90°.", "Iadd.", ", that is, the forward edge surface should be perpendicular to the longitudinal axis of the plates 58.", "Iaddend.", "In operation.", "Iadd.", ", .", "Iaddend.", "a workman will cause the ramp 12 to be raised by pulling the chain 84 which releases the ramp hold down 30 and allows the spring 22 to .", "bias.", "Iadd.", "swing or pivot .", "Iaddend.", "the ramp upward .", "Iadd.", "to a fully raised position.", "Iaddend..", "He will then walk out on the ramp 12 .", "to force it down.", "Iadd.", "and his weight will then cause the ramp to swing downwardly.", "Iaddend..", "If for some reason.", "Iadd.", ", .", "Iaddend.", "he does not wish the lip 32 to project, he will .", "Iadd.", "first .", "Iaddend.", "pull the chain 86 which will force the knuckle joint 48 over .", "Iadd.", "center to place the arm 36 and bar 46 in a relative position as in FIG. 9 where the arm 36 will be ineffective .", "Iaddend.", "and will not project the lip 32 and the ramp will simply descend .", "to.", "Iadd.", "with the lip 32 hanging downward in .", "Iaddend.", "the position shown in FIG. .", "[[.", "].2.", "Iadd[.", "].3.", "Iaddend.", "However, as a general rule.", "Iadd.", ", .", "Iaddend.", "the desire will be to project the lip.", "Accordingly, as the weight of the workman causes the ramp to descend.", "Iadd.", ", .", "Iaddend.", "the arm 36, acting through lugs 44, will cause the lip 32 to .", "Iadd.", "swing upwardly with respect to the ramp 12 and .", "Iaddend.", "project outward as the ramp 12 pivots downward .", "Iadd.", "as sequentially shown in FIGS. 6-9.", "Iaddend..", "The arm 36 will continue to project the lip until just after the bar 46 and arm 36 become a straight line at which time the knuckle joint .", "[[.", "].46 will.", "Iadd[.", "].48 passes through center permitting the arm and bar to .", "Iaddend.", "bend .", "Iadd.", "as shown in FIG. 9 .", "Iaddend.", "and the force to project the lip 32 will be released.", "Observing FIGS. 2-5.", "Iadd.", ", .", "Iaddend.", "it will be seen that at the rest position .", "Iadd.", "of FIG. 2, .", "Iaddend.", "with the lip 32 approximately perpendicular to .", "the.", "Iadd.", "a .", "Iaddend.", "ramp 12 and behind the keeper 88 .", "Iadd.", "secured to the frame 14.", "Iaddend.", ", the pin 76 is at the forwardmost portion of the U-shaped bracket 66.", "Similarly, in FIG. 3 with the ramp raised to its maximum, the pin 76 is still forward because the lip 32 is still at an angle perpendicular to the ramp.", "As the lip .", "projector.", "Iadd.", "projection arm .", "Iaddend[.", "].36 begins to project .", "Iadd.", "or swing .", "Iaddend.", "the lip .", "Iadd.", "upwardly .", "Iaddend.", "during the walk down, the plates 58 will be pulled forward by the lugs 74 and the pin 76 being .", "Iadd.", "held .", "Iaddend.", "stationary .", "Iadd.", "by its supporting lugs 78 .", "Iaddend.", "will slide to the rear of the U-shaped bracket to a point most remote from the lip .", "Iadd.", "since the block 66 is carried with the forwardly moving plates 58 through frictional clamping engagement of the bracket 66 and cover plate 68 with the two plates 58.", "Iaddend..", "At that point the bracket will .", "Iadd.", "be restrained against further movement with the plates 58 and will .", "Iaddend.", "begin to slide .", "Iadd.", "along the plates.", "This movement continues .", "Iaddend.", "until the .", "pin pushes the bracket to a point where the upwardly opening U-shape moves under the.", "notches 82 .", "Iadd.", "align with the groove 80 which was previously aligned with the pin 76.", "Iaddend..", "The weight of the apparatus 56 .", "Iadd.", "then .", "Iaddend.", "causes it to fall such that the pin .", "Iadd[.", "].76 .", "Iaddend.", "moves into the .", "Iadd.", "aligned groove 80 and .", "Iaddend.", "notches .", "Iadd[.", "].82 as shown in FIG. 4.Iaddend..", "At this point in time or slightly thereafter, the lip projector is designed to release as the knuckle joint 48 passes equilibrium and flips over.", "The bolt 54 should be adjusted to provide that the knuckle joint 48 will not flip over until the pin 76 is engaged in the .", "slots.", "Iadd.", "aligned groove 80 and notches .", "Iaddend[.", "].82.", "Thereby, lip lock apparatus 56 will then hold the lip 32 in projected position until the lip engages the bed of a truck or other vehicle .", "Iadd[.", "].90 .", "Iaddend.", "to be serviced.", "With the lip .", "Iadd[.", "].32 engaging the bed of the truck .", "Iadd[.", "].90 as shown in FIG. 5, .", "Iaddend.", "the ramp .", "Iadd[.", "].12 .", "Iaddend.", "will continue to descend and the lip will be .", "Iadd.", "further .", "Iaddend.", "pivoted .", "Iadd.", "or projected .", "Iaddend.", "to a position near parallel with the ramp.", "During this sequence the rear sloping .", "Iadd.", "edge .", "Iaddend.", "surface of the .", "slot.", "Iadd.", "notches .", "Iaddend[.", "].82 will cam the pin .", "Iadd[.", "].76 relatively downward and .", "Iaddend.", "out of .", "slot.", "Iadd.", "notches .", "Iaddend[.", "].82 and .", "Iadd.", "the block groove 80 and .", "Iaddend.", "back into the U-shaped bracket 66 as the plates 58 are pulled even further forward .", "Iadd.", "and thus unlatches the lip lock apparatus.", "Iaddend..", "As the .", "pin moves back, it will force.", "Iadd.", "plates 58 move relatively forward, .", "Iaddend.", "the block 62 .", "to the rear by pressing against the rear surface of the groove 80 and.", "Iadd.", "will become positioned further rearward on the plates when, .", "Iaddend.", "at the full extension of the lip, the block will be almost to the rear of the plates 58 as shown in FIG. 5. .", "Iadd.", "It will be noted here that the plates 58, except when relatively positioned to align the notches 82 with the groove 80 and pin 76, will be supported on the pin 76 and will be free to slide on top of the pin.", "Iaddend.", "When the truck .", "Iadd[.", "].90 .", "Iaddend.", "pulls away and the lip .", "Iadd[.", "].32 .", "Iaddend.", "is .", "released.", "Iadd.", "thereby freed .", "Iaddend.", "to fall to the perpendicular position, .", "the pin will first move to the forward portion of the bracket 66 before it begins to drive the bracket forward.", "With the pin in the forward position of the bracket 66 it cannot slide into notches 82 because the block 62 at the forward portion of the bracket 66 prevents such vertical movement, groove 80 is not aligned with the pin, note particularly FIG. 10..", "Iadd.", "with respect to the ramp 12, it will be seen that the lip lock apparatus 56 remains unlatched and ineffective and thus permit the lip to pivot downwardly.", "As the lip 32 pivots downwardly, the plates 58 will slide rearwardly along and be supported on the pin 76.", "During initial rearward movement of the plates 58, the block 62 will be carried rearwardly therewith through the frictional clamping engagement of the bracket 66 and cover plate 68.", "However, the block 62 will be restrained against further rearward movement when the pin 76 reaches the forward end of the bracket 66.", "Continued rearward movement of the plates 58 will result in the notches 82 moving into alignment with the pin 76 but the plates 58 will not drop because the groove 80 in the block 62 is not concurrently aligned therewith.", "The block 62 thus supports the plates 58 for continued rearward movement as the block is supported on the pin 76 and the plates are then supported on the bracket 66 carried by the block.", "Thus, the plates 58 may continue their rearward movement thereby permitting the lip to continue pivoting to its full down position.", "Iaddend.", "A lip lock release means is provided for those occasions where the lip .", "Iadd[.", "].32 .", "Iaddend.", "is projected and locked into place but then there is some reason to release the lip without having engaged the bed of a truck or there is no truck at the dock.", "This release means is provided in the form of a bolt 92 projecting upward from the frame 14.", "When the ramp descends below the level of the surrounding dock.", "Iadd.", ", .", "Iaddend.", "the lower surface of the bracket 66 will engage the top of the bolt 92.", "This will push the plates 58 .", "Iadd.", "and block 62 .", "Iaddend.", "upward and disengage the pin 76 from the .", "slots.", "Iadd.", "groove 80 and notches .", "Iaddend[.", "].82.", "at which time.", "Iadd.", "This unlatches the lock apparatus 56 as previously described and .", "Iaddend.", "the lip 32 will fall by gravity to its pendant position.", "Having thus described the invention in its preferred embodiment, it will be clear to those having ordinary skill in the art that obvious modifications may be made without departing from the spirit of the invention.", "Additionally, the language used to describe the invention is not considered limiting.", "Rather it is intended that the only limitations on the scope of the invention be as set out in the appended claims." ]
REFERENCE TO RELATED APPLICATION Reference is made to issued U.S. Pat. No. 6,289,743 by the same inventor which is hereby incorporated by reference. This utility patent draws priority from provisional application 60/410,341, filed Sep. 13, 2002. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to testing shoes, such as athletic shoes. The present invention relates to testing athletic shoes by first establishing a baseline of the shoe's resistance to rotational forces at a first temperature, and then by establishing a functional norm of the shoe's resistance to rotational forces at a second temperature at which it would be worn. These results would be quantified and grouped by the amount of resistance offered at the different conditions. Additional tests would subject the shoe to stress: i.e. a higher than normal temperature, or to wear the shoe for a set time or distance and then to again compare the resistance to axial torque in relation to both the baseline and functional norm. Based on these results, it would permit a consumer or advocate to determine what shoe is proper for the athlete or customer who will wear it. 2. Description of the Prior Art As noted above, applicant's previous U.S. Pat. No. 6,289,743 is incorporated by reference and is directed towards a shoe testing apparatus. This apparatus allows for the person using it to determine the amount of resistance to an axial twisting motion subjected to an athletic shoe. This resistance is measured in inch-pounds. Any units of measurement for torque may be used, in both english and metric units. This is important in that incorrect shoe selection and fitting can result in injury to the wearer. Particularly, a user whose foot exhibits a large amount of pronation is susceptible to such conditions as shin splints, plantar fascitis, posterior tibialis tendonitis and general knee pain. A pronated foot is characterized by a navicular drop of over 11 mm. The navicular bone is located in the medial midfoot and is the bone located distal to the talus and proximal the medial cuneform. Excessive pronantion may be caused by a habitual gait that rotates the tibia and femur in an inappropriate manner and may also be exacerbated by the weight of the runner or walker. The gait of the person in question is examined to estimate the amount the amount of pronation caused by the stance in the contact, midstance, and propulsion phases of walking, running, hiking, etc. Applicant's previous patent allows for various shoes to be tested in regards to axial rotation. The present invention improves on this technique by allowing various models of shoes to be tested after they have been subject to various real life stresses. Athletic shoes of the type commonly purchased today have varying amounts of support. This support is affected by the material of the uppers, the boarded lasts of the shoe, and the materials used in the midsole, such as polyurethane, plastic, and EVA (Ethyl Vinyl Acetate). The present invention allows the user of applicant's apparatus (the '743 patent) to determine the amount of axial rotation that various brands of shoes allow after being subject to stress. Shoes “out of the bog” a resistance value (measured in inch-pounds) that may be markedly different at a higher temperature or after repetitive motion The present invention measures (first) a baseline value at, for example, 66 degrees Fahrenheit, then a functional value after being maintained at, for example 88 degrees Farenheit for a time period of, for example, 72 hours or so. Second, the present invention allows for the user to test the loss of resistance after a set period of activity, for example a 10 km run. In both cases, a fatigue factor, represented as a percentage loss of resistance to axial rotation may be determined from a number of shoes of Various models and brands. SUMMARY OF THE INVENTION The present invention provides a method of testing and comparing various types of athletic shoes under stress. Resistance to axial rotation is measured in inch-pounds at a baseline temperature. Then the shoe is subject to either environmental (temperature) stress or kinetic (repetitive motion) stress. After a set period of time at a certain temperature or after a set amount of physical activity while the shoes are being worn, the shoe is then again subjected to axial rotation and the resistance in inch-pounds is again measured. The percentage difference is registered as a fatigue factor and allows the user to determine the brand of shoe that would or would not be advantageous to a certain customer's or athlete's gait. Other comparison tests may be performed. The shoes may be stressed by immersion in water, mud, bicycling, running, cross-country running and the like. It is an object of the invention to provide a method of stress testing footwear wherein a baseline of resistance to axial rotation in an athletic shoe may be determined. It is another object of the invention to provide a method of stress testing footwear wherein the user may determine an optimal shoe type or brand for a customer or athlete depending on an analysis of the various subphases of the stance during movement. Yet another object of the invention is to provide a method of stress testing footwear wherein the user may determine the fatigue factor in the shoe represented by a percentage loss of resistance in inch-pounds after the shoe has undergone a predetermined amount of stress. Yet another object of the invention is to provide a method of stress testing footwear wherein the fatigue factor is determined after the shoe has been maintained at a specific temperature for a specific period of time. Still yet another object of the invention is to provide a method of stress testing footwear wherein the fatigue factor is determined after the shoe has been worn during a predetermined amount of exercise: i.e. running or walking a set distance, or participating in an athletic event for a certain period of time. Yet another object of the invention is to provide a method of stress testing footwear wherein a large collection of data points may be determined for a specific brand of shoe so that the temperature of kinetic breakdown of the shoe support may be determined over time. Still yet another object of the invention is to provide a method of stress testing footwear wherein a large collection of data points may be determined for various brands and models of shoes under the same type of predetermined stress and thus the user may determine which brand is optimal for a specific gait in an event or an environment. These together with still other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this,disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and the above objects as well as objects other than those set forth above will become more apparent after a study of the following detailed description thereof. Such description makes reference to the annexed drawings wherein: FIG. 1 is a view showing the various forces and how they act on the leg during harmful pronation of the foot during the subphases of a person's stance. FIG. 2 is a block diagram of the method of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a method of testing athletic footwear after it has been subject to stress and calculating a fatigue factor as a percentage of lost stability from a predetermined baseline. This technique allows the user to determine what the best brand or the type of shoe would be for an athlete or a customer depending on the observed qualities of their gait regarding foot pronation and the amount of environmental or kinetic stress that the footwear would be subjected to during usual activity. The stability of the shoe is basically how well a shoe supports the user's arch and heel and, especially in regards to the instant invention, counteracts the rotational forces of pronation. A pronated foot, or hyper-pronated foot can be characterized by a navicular drop of over 11 mm. This drop of the navicular, located between the talus (heel) and the metatarsals (toes) of the human foot can lead to a variety of conditions such as shin splints, plantar fascitis, posterior tibialis tendonitis, and knee pain which will be discussed further hereinbelow under a section that refers to clinical observations made by applicant. Turn to FIG. 1 for a diagram demonstrating harmful pronation of the foot during the subphases of a person's stance. At 10 there is indicated the tibia rotation from the heel strike to full weight bearing. This is where posterior tibial tendonitis over the pronation may develop. The tibia rotates internally as the arch drops. At 12 is indicated the location of the navicular drop. Areas where what are called “shin splints” could develop are indicated at 14 and 15 . 14 indicates the area of antero-lateral shin splints and 15 indicates the area where medial shin splints can develop. Areas that subsequent knee pain could develop in are indicated at 16 as the femur rotates internally over the arch drop. This can additionally cause llio-tibial band pain indicated in the area at 17 . Generalised hip pain can also develop over pronation as indicated at 18 . All of these problems are in some way addressable by preventing the pronation of the foot and the navicular drop that causes the stress. In some cases, the gait may be habitual or brought on by physical causes. In many cases, the weight of the athlete (runner, walker) exacerbates the problem. Proper support of the foot goes a long way towards addressing this problem. The instant invention is a method of ascertaining what kind or which brand of shoe is best for a certain person performing a specified activity. Turning to FIG. 2, the overall steps of the instant invention are generally designated at 20 . The first step 22 is to establish a baseline. In the preferred embodiment described herein, this baseline is established at 66° F. It should be emphasized at this point that a wide range of temperatures could be used to set this baseline. Lower temperatures could be chosen if the athletic shoe was to be used in a sub arctic or arctic environment. Again, a skilled practitioner would find a wide range of baseline establishment temperatures to be workable. In the embodiment described herein, this baseline of 66° is set by first maintaining the shoe in a controlled environment for at least 72 hours. This amount of time gives every portion of the shoe, even the interior midsole a chance to reach the desired temperature. If desired, a thermometer (not shown) could be used to ascertain the temperature of the interior parts of the shoe. The shoe in question is then placed on the apparatus described in applicant's issued U.S. Pat. No. 6,289,743. This apparatus (incorporated by reference) allows the user to measure the resistance to axial torque in a desired direction. The reading is made in inch-pounds, but it should be noted that other scales could easily be used. On or more shoes can be tested in a sequence, with a plurality of brands to allow a multitude of data points to be collected at the desired baseline. This first measuring and recording step is indicated at 24 in FIG. 2 . The discussion now turns to the stress subjecting step which is indicated at 26 in FIG. 2. A wide variety of stresses can be put on the shoe. Two of them will be discussed in the embodiment described herein. The first is an environmental test, specifically a temperature test There are a number of reasons why this test is desirable. First, depending on the environment in which the shoe is going to be used, different ambient shoe temperatures can be expected. A sharp difference would be seen if the shoe were to be used for example during the month of July in Portland, Oreg. versus the same time period in Las Vegas, Nev. The second location would subject the shoe to a much higher ambient temperature. Thus, in the first environmental stressor step, the shoe is raised to a predetermined temperature and maintained at that temperature for a predetermined time. In one example of the invention, the shoe in question is placed in an environment of about 88° Fahrenheit and maintained in that environment for about 72 hours. It should be understood that these temperatures and times are only an example of one possible proposed test condition and should not be considered to be limiting the scope of the invention in any way. A skilled practitioner could use a spectrum of temperatures and times depending on the perceived environment in which the shoe was going to be used to get useful results from the apparatus. By comparing the torque produced at the first temperature versus the torque produced at the second temperature one can objectively measure and compare the different models and brands of athletic shoes. This gives an objective quality measurement for each model and brand of shoe which can then be employed to assist people with different shoe requirements. By selecting the correct shoe, one may reduce pain caused by pronation or improper gait. It is also to be understood that one of the main reasons that measurements are taken at a higher temperature is due to body heat and how it effects the shoe. The temperature at which the shoe is exposed to is related to body heat as well as external temperature. The second stressor test would be a kinetic stressor. This basically would involve repetitive movement of the shoe to either simulate an athletic activity or to perform the athletic activity. The user could, for example, run a ten-kilometer course or play a half hour of soccer. Other activities could, of course, be used, or a mechanical mechanism (not shown) could manipulate the shoe. Referring to reference numeral 28 of FIG. 2, the second measuring and recording step is shown. This is accomplished in the same manner as the first measuring and recording step 24 . Again the scale is read out in inch-pounds but other values could be used. Lastly, the calculation of the fatigue factor is accomplished. This factor is a percentage of the loss of resistance to axial rotation. This step is indicated at 30 . The discussion now turns to stability of various types of shoes and the classifications that applicant has developed for grouping them. Level 1 Stability is for excessive pronators to moderate pronators. Moderate pronators who experience hip, knee, shin, foot, or ankle pain benefit from this level of stability. Runners who are moderate pronators and are of large or heavy stature or walkers who are moderate to excessive pronators and who experience hip, knee, shin, foot, or ankle pain also benefit from this, the highest level of stability with the most resistance to axial torque. Level 2 Stability is for mild to moderate pronators who have no physical pain or for heavy runners with either neutral feet or mild pronation. Additionally, this level of stability is called for in supinators of heavy stature. Level 3 Stability is for neutral to mild pronators who have no physical symptoms or for runners with neutral feet or mild pronation of light to moderate stature. Additionally, this level of stability is appropriate to supinators of light to moderate stature. CLINICAL OBSERVATIONS The discussion now turns to observed conditions and the shoe requirements and recommendations therefore. A plurality of tables of mens and womens shoes with exemplary test results were provided in the provisional application from which this utility application is based. In the case of an athlete or customer of heavy stature, the shoe requirement would be maximum stability for support. Thus, a level 1 stability shoe would be recommended. For moderate to excessive pronation, flat or “mobile” feet the requirement would be that the long axis of the shoe should provide maximum resistance to pronation. The shoe should also have a firm heel counter. This helps the foot become more rigid and increases its efficiency as a lever arm. A level 1 type shoe is recommended. In the case of a supinated foot (the opposite of pronation), a rigid foot, or a foot that lacks natural cushioning, what is required is a firm heel counter with a soft midsole to provide the needed cushioning. A level 2 stability shoe is appropriate. For someone with ankle instability, the shoe should have maximum resistance to pronation along the long axis of the shoe. The shoe should have a firm heel counter. These two features translate stability to the ankle. This calls for a level 1 stability shoe. Knee pain or “runner's knee” which is associated with pronation also calls for the long axis of the shoe to have maximum resistance to pronation during the weight-bearing phase of the gait. This provides both better alignment for the patella and allows the quadriceps to work more efficiently. A level 1 stability shoe in recommended. The ilio-tibial band syndrome is also associated with pronation. Again, the long axis of the shoe should have maximum resistance to foot rotation during the weigh-bearing phase of the gait. The slackens the ilio-tibial band which reduces friction and irritation of the hip and outside the knee. This condition is best served by a level 1 stability shoe. With Achilles tendonitis maximum shoe stability is necessary to turn the pronated foot into a more rigid lever arm. The increases the efficiency of both the Achilles tendon and the calf muscles. Additionally, heel lifts may be helpful. A level 1 stability shoe is recommended. For shin splints, either medial (posterior tibial) or antero-lateral, the long axis of the shoe should again exhibit maximum resistance to rotation. This will reduce the undesired forces on the lower leg. Level 1 stability shoes are indicated. In the case of bunions or first metatarsal head pain, once again the shoe should have maximum resistance to pronation of the foot. This will reduce the translation of improper forces to the big toe as the shoe wearer moves through the push-off phase of the gait. The shoe should have a wide toe box to prevent pressure on the first metatarsal head. Level 1 stability is indicated. In plantar fascitis, the pronation of the foot stretches the plantar fascia which causes soreness and tenderness on medial and plantar surfaces of the heel. Maximum stability: i.e. resistance to pronatiom is again helpful along with a good toe spring in the shoe to reduce stretching of the plantar fascia. Level 1 stability is recommended. It should be emphasized that the instant invention is not in any way limited to the embodiments as they are described above but encompasses all embodiments as described in the scope of then following claims.
A method of testing athletic shoes is provided. The testing subjects athletic shoes to different temperature conditions in one test or different kinetic forces in another test. After undergoing the stressor (temperature, kinetic forces, other) the axial resistance exhibited by the shoe is measured by placing the shoe in the shoe testing device. The device ascertains the amount of torque required to rotate or twist each shoe to a standard amount. These results permits the different models and brands of athletic shoe to be independently categorized and grouped based on their performance with relation to the different stressor placed on the shoe. This would then permit the consumer, health professional and/or consultant to choose an athletic shoe which would assist in correcting pain caused by various degrees of motion in the foot or lower leg. By utilizing the categorizations, along with the needs of the individual, one may select an athletic shoe which can treat the effects of pronation and improper gait.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "REFERENCE TO RELATED APPLICATION Reference is made to issued U.S. Pat. No. 6,289,743 by the same inventor which is hereby incorporated by reference.", "This utility patent draws priority from provisional application 60/410,341, filed Sep. 13, 2002.", "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates generally to testing shoes, such as athletic shoes.", "The present invention relates to testing athletic shoes by first establishing a baseline of the shoe's resistance to rotational forces at a first temperature, and then by establishing a functional norm of the shoe's resistance to rotational forces at a second temperature at which it would be worn.", "These results would be quantified and grouped by the amount of resistance offered at the different conditions.", "Additional tests would subject the shoe to stress: i.e. a higher than normal temperature, or to wear the shoe for a set time or distance and then to again compare the resistance to axial torque in relation to both the baseline and functional norm.", "Based on these results, it would permit a consumer or advocate to determine what shoe is proper for the athlete or customer who will wear it.", "Description of the Prior Art As noted above, applicant's previous U.S. Pat. No. 6,289,743 is incorporated by reference and is directed towards a shoe testing apparatus.", "This apparatus allows for the person using it to determine the amount of resistance to an axial twisting motion subjected to an athletic shoe.", "This resistance is measured in inch-pounds.", "Any units of measurement for torque may be used, in both english and metric units.", "This is important in that incorrect shoe selection and fitting can result in injury to the wearer.", "Particularly, a user whose foot exhibits a large amount of pronation is susceptible to such conditions as shin splints, plantar fascitis, posterior tibialis tendonitis and general knee pain.", "A pronated foot is characterized by a navicular drop of over 11 mm.", "The navicular bone is located in the medial midfoot and is the bone located distal to the talus and proximal the medial cuneform.", "Excessive pronantion may be caused by a habitual gait that rotates the tibia and femur in an inappropriate manner and may also be exacerbated by the weight of the runner or walker.", "The gait of the person in question is examined to estimate the amount the amount of pronation caused by the stance in the contact, midstance, and propulsion phases of walking, running, hiking, etc.", "Applicant's previous patent allows for various shoes to be tested in regards to axial rotation.", "The present invention improves on this technique by allowing various models of shoes to be tested after they have been subject to various real life stresses.", "Athletic shoes of the type commonly purchased today have varying amounts of support.", "This support is affected by the material of the uppers, the boarded lasts of the shoe, and the materials used in the midsole, such as polyurethane, plastic, and EVA (Ethyl Vinyl Acetate).", "The present invention allows the user of applicant's apparatus (the '743 patent) to determine the amount of axial rotation that various brands of shoes allow after being subject to stress.", "Shoes “out of the bog”", "a resistance value (measured in inch-pounds) that may be markedly different at a higher temperature or after repetitive motion The present invention measures (first) a baseline value at, for example, 66 degrees Fahrenheit, then a functional value after being maintained at, for example 88 degrees Farenheit for a time period of, for example, 72 hours or so.", "Second, the present invention allows for the user to test the loss of resistance after a set period of activity, for example a 10 km run.", "In both cases, a fatigue factor, represented as a percentage loss of resistance to axial rotation may be determined from a number of shoes of Various models and brands.", "SUMMARY OF THE INVENTION The present invention provides a method of testing and comparing various types of athletic shoes under stress.", "Resistance to axial rotation is measured in inch-pounds at a baseline temperature.", "Then the shoe is subject to either environmental (temperature) stress or kinetic (repetitive motion) stress.", "After a set period of time at a certain temperature or after a set amount of physical activity while the shoes are being worn, the shoe is then again subjected to axial rotation and the resistance in inch-pounds is again measured.", "The percentage difference is registered as a fatigue factor and allows the user to determine the brand of shoe that would or would not be advantageous to a certain customer's or athlete's gait.", "Other comparison tests may be performed.", "The shoes may be stressed by immersion in water, mud, bicycling, running, cross-country running and the like.", "It is an object of the invention to provide a method of stress testing footwear wherein a baseline of resistance to axial rotation in an athletic shoe may be determined.", "It is another object of the invention to provide a method of stress testing footwear wherein the user may determine an optimal shoe type or brand for a customer or athlete depending on an analysis of the various subphases of the stance during movement.", "Yet another object of the invention is to provide a method of stress testing footwear wherein the user may determine the fatigue factor in the shoe represented by a percentage loss of resistance in inch-pounds after the shoe has undergone a predetermined amount of stress.", "Yet another object of the invention is to provide a method of stress testing footwear wherein the fatigue factor is determined after the shoe has been maintained at a specific temperature for a specific period of time.", "Still yet another object of the invention is to provide a method of stress testing footwear wherein the fatigue factor is determined after the shoe has been worn during a predetermined amount of exercise: i.e. running or walking a set distance, or participating in an athletic event for a certain period of time.", "Yet another object of the invention is to provide a method of stress testing footwear wherein a large collection of data points may be determined for a specific brand of shoe so that the temperature of kinetic breakdown of the shoe support may be determined over time.", "Still yet another object of the invention is to provide a method of stress testing footwear wherein a large collection of data points may be determined for various brands and models of shoes under the same type of predetermined stress and thus the user may determine which brand is optimal for a specific gait in an event or an environment.", "These together with still other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this,disclosure.", "For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.", "BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and the above objects as well as objects other than those set forth above will become more apparent after a study of the following detailed description thereof.", "Such description makes reference to the annexed drawings wherein: FIG. 1 is a view showing the various forces and how they act on the leg during harmful pronation of the foot during the subphases of a person's stance.", "FIG. 2 is a block diagram of the method of the invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a method of testing athletic footwear after it has been subject to stress and calculating a fatigue factor as a percentage of lost stability from a predetermined baseline.", "This technique allows the user to determine what the best brand or the type of shoe would be for an athlete or a customer depending on the observed qualities of their gait regarding foot pronation and the amount of environmental or kinetic stress that the footwear would be subjected to during usual activity.", "The stability of the shoe is basically how well a shoe supports the user's arch and heel and, especially in regards to the instant invention, counteracts the rotational forces of pronation.", "A pronated foot, or hyper-pronated foot can be characterized by a navicular drop of over 11 mm.", "This drop of the navicular, located between the talus (heel) and the metatarsals (toes) of the human foot can lead to a variety of conditions such as shin splints, plantar fascitis, posterior tibialis tendonitis, and knee pain which will be discussed further hereinbelow under a section that refers to clinical observations made by applicant.", "Turn to FIG. 1 for a diagram demonstrating harmful pronation of the foot during the subphases of a person's stance.", "At 10 there is indicated the tibia rotation from the heel strike to full weight bearing.", "This is where posterior tibial tendonitis over the pronation may develop.", "The tibia rotates internally as the arch drops.", "At 12 is indicated the location of the navicular drop.", "Areas where what are called “shin splints”", "could develop are indicated at 14 and 15 .", "14 indicates the area of antero-lateral shin splints and 15 indicates the area where medial shin splints can develop.", "Areas that subsequent knee pain could develop in are indicated at 16 as the femur rotates internally over the arch drop.", "This can additionally cause llio-tibial band pain indicated in the area at 17 .", "Generalised hip pain can also develop over pronation as indicated at 18 .", "All of these problems are in some way addressable by preventing the pronation of the foot and the navicular drop that causes the stress.", "In some cases, the gait may be habitual or brought on by physical causes.", "In many cases, the weight of the athlete (runner, walker) exacerbates the problem.", "Proper support of the foot goes a long way towards addressing this problem.", "The instant invention is a method of ascertaining what kind or which brand of shoe is best for a certain person performing a specified activity.", "Turning to FIG. 2, the overall steps of the instant invention are generally designated at 20 .", "The first step 22 is to establish a baseline.", "In the preferred embodiment described herein, this baseline is established at 66° F. It should be emphasized at this point that a wide range of temperatures could be used to set this baseline.", "Lower temperatures could be chosen if the athletic shoe was to be used in a sub arctic or arctic environment.", "Again, a skilled practitioner would find a wide range of baseline establishment temperatures to be workable.", "In the embodiment described herein, this baseline of 66° is set by first maintaining the shoe in a controlled environment for at least 72 hours.", "This amount of time gives every portion of the shoe, even the interior midsole a chance to reach the desired temperature.", "If desired, a thermometer (not shown) could be used to ascertain the temperature of the interior parts of the shoe.", "The shoe in question is then placed on the apparatus described in applicant's issued U.S. Pat. No. 6,289,743.", "This apparatus (incorporated by reference) allows the user to measure the resistance to axial torque in a desired direction.", "The reading is made in inch-pounds, but it should be noted that other scales could easily be used.", "On or more shoes can be tested in a sequence, with a plurality of brands to allow a multitude of data points to be collected at the desired baseline.", "This first measuring and recording step is indicated at 24 in FIG. 2 .", "The discussion now turns to the stress subjecting step which is indicated at 26 in FIG. 2. A wide variety of stresses can be put on the shoe.", "Two of them will be discussed in the embodiment described herein.", "The first is an environmental test, specifically a temperature test There are a number of reasons why this test is desirable.", "First, depending on the environment in which the shoe is going to be used, different ambient shoe temperatures can be expected.", "A sharp difference would be seen if the shoe were to be used for example during the month of July in Portland, Oreg.", "versus the same time period in Las Vegas, Nev.", "The second location would subject the shoe to a much higher ambient temperature.", "Thus, in the first environmental stressor step, the shoe is raised to a predetermined temperature and maintained at that temperature for a predetermined time.", "In one example of the invention, the shoe in question is placed in an environment of about 88° Fahrenheit and maintained in that environment for about 72 hours.", "It should be understood that these temperatures and times are only an example of one possible proposed test condition and should not be considered to be limiting the scope of the invention in any way.", "A skilled practitioner could use a spectrum of temperatures and times depending on the perceived environment in which the shoe was going to be used to get useful results from the apparatus.", "By comparing the torque produced at the first temperature versus the torque produced at the second temperature one can objectively measure and compare the different models and brands of athletic shoes.", "This gives an objective quality measurement for each model and brand of shoe which can then be employed to assist people with different shoe requirements.", "By selecting the correct shoe, one may reduce pain caused by pronation or improper gait.", "It is also to be understood that one of the main reasons that measurements are taken at a higher temperature is due to body heat and how it effects the shoe.", "The temperature at which the shoe is exposed to is related to body heat as well as external temperature.", "The second stressor test would be a kinetic stressor.", "This basically would involve repetitive movement of the shoe to either simulate an athletic activity or to perform the athletic activity.", "The user could, for example, run a ten-kilometer course or play a half hour of soccer.", "Other activities could, of course, be used, or a mechanical mechanism (not shown) could manipulate the shoe.", "Referring to reference numeral 28 of FIG. 2, the second measuring and recording step is shown.", "This is accomplished in the same manner as the first measuring and recording step 24 .", "Again the scale is read out in inch-pounds but other values could be used.", "Lastly, the calculation of the fatigue factor is accomplished.", "This factor is a percentage of the loss of resistance to axial rotation.", "This step is indicated at 30 .", "The discussion now turns to stability of various types of shoes and the classifications that applicant has developed for grouping them.", "Level 1 Stability is for excessive pronators to moderate pronators.", "Moderate pronators who experience hip, knee, shin, foot, or ankle pain benefit from this level of stability.", "Runners who are moderate pronators and are of large or heavy stature or walkers who are moderate to excessive pronators and who experience hip, knee, shin, foot, or ankle pain also benefit from this, the highest level of stability with the most resistance to axial torque.", "Level 2 Stability is for mild to moderate pronators who have no physical pain or for heavy runners with either neutral feet or mild pronation.", "Additionally, this level of stability is called for in supinators of heavy stature.", "Level 3 Stability is for neutral to mild pronators who have no physical symptoms or for runners with neutral feet or mild pronation of light to moderate stature.", "Additionally, this level of stability is appropriate to supinators of light to moderate stature.", "CLINICAL OBSERVATIONS The discussion now turns to observed conditions and the shoe requirements and recommendations therefore.", "A plurality of tables of mens and womens shoes with exemplary test results were provided in the provisional application from which this utility application is based.", "In the case of an athlete or customer of heavy stature, the shoe requirement would be maximum stability for support.", "Thus, a level 1 stability shoe would be recommended.", "For moderate to excessive pronation, flat or “mobile”", "feet the requirement would be that the long axis of the shoe should provide maximum resistance to pronation.", "The shoe should also have a firm heel counter.", "This helps the foot become more rigid and increases its efficiency as a lever arm.", "A level 1 type shoe is recommended.", "In the case of a supinated foot (the opposite of pronation), a rigid foot, or a foot that lacks natural cushioning, what is required is a firm heel counter with a soft midsole to provide the needed cushioning.", "A level 2 stability shoe is appropriate.", "For someone with ankle instability, the shoe should have maximum resistance to pronation along the long axis of the shoe.", "The shoe should have a firm heel counter.", "These two features translate stability to the ankle.", "This calls for a level 1 stability shoe.", "Knee pain or “runner's knee”", "which is associated with pronation also calls for the long axis of the shoe to have maximum resistance to pronation during the weight-bearing phase of the gait.", "This provides both better alignment for the patella and allows the quadriceps to work more efficiently.", "A level 1 stability shoe in recommended.", "The ilio-tibial band syndrome is also associated with pronation.", "Again, the long axis of the shoe should have maximum resistance to foot rotation during the weigh-bearing phase of the gait.", "The slackens the ilio-tibial band which reduces friction and irritation of the hip and outside the knee.", "This condition is best served by a level 1 stability shoe.", "With Achilles tendonitis maximum shoe stability is necessary to turn the pronated foot into a more rigid lever arm.", "The increases the efficiency of both the Achilles tendon and the calf muscles.", "Additionally, heel lifts may be helpful.", "A level 1 stability shoe is recommended.", "For shin splints, either medial (posterior tibial) or antero-lateral, the long axis of the shoe should again exhibit maximum resistance to rotation.", "This will reduce the undesired forces on the lower leg.", "Level 1 stability shoes are indicated.", "In the case of bunions or first metatarsal head pain, once again the shoe should have maximum resistance to pronation of the foot.", "This will reduce the translation of improper forces to the big toe as the shoe wearer moves through the push-off phase of the gait.", "The shoe should have a wide toe box to prevent pressure on the first metatarsal head.", "Level 1 stability is indicated.", "In plantar fascitis, the pronation of the foot stretches the plantar fascia which causes soreness and tenderness on medial and plantar surfaces of the heel.", "Maximum stability: i.e. resistance to pronatiom is again helpful along with a good toe spring in the shoe to reduce stretching of the plantar fascia.", "Level 1 stability is recommended.", "It should be emphasized that the instant invention is not in any way limited to the embodiments as they are described above but encompasses all embodiments as described in the scope of then following claims." ]
CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a divisional application of U.S. Ser. No. 10/543,187, filed Jul. 21, 2005, and the entire disclosure of which is hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention relates to a method for gas stunning of poultry. BACKGROUND OF THE INVENTION [0003] Over time, many different methods have been proposed for gas stunning of poultry arriving at the poultry slaughterhouse in transport crates, with no remarkable success. In practice however, several parameters must be considered in order to be able to optimize a method for gas stunning of poultry for slaughter. [0004] To optimize the method, the following parameters must be considered: Conveying speed (capacity of the system). Size and number of birds in the transport crates. The physical condition of the poultry flock which is determined by continuously observing variations in stress condition or resistance of the poultry which are significant for determining the time necessary for stunning the poultry which further may vary because of conditions in broiler houses, temperatures, transport time, and waiting time in the slaughterhouse. [0008] To optimize the gas stunning it is furthermore necessary to be able to continuously consider all these parameters prior to and during gas stunning of the poultry supplies delivered to the slaughterhouse, and continuously apply the most advantageous parameters to achieve optimum gas stunning of the actual chicken flock at any time to be stunned and slaughtered, respectively. [0009] To optimize these parameters, different periods of stunning time can be applied, but variations in the gas concentration, and variations of gas concentration in the different sections of the conveying route must also be considered, dependent on the conveying route length and conveying route location in the stunning chamber. [0010] The gas concentration may be monitored and controlled by means of sensors having different locations, and a PLC control system. Adjustment of the stunning time and simultaneous variation of the gas concentration require a change in the previously used methods by which a given slaughtering capacity of number of birds per minute required a fixed conveying time through stunning chamber. A given rate of slaughtering (slaughtering capacity) will always be determined by other subsequent parameters that cannot be changed right away why they are maintained. Consequently it may furthermore be necessary to be able to change the degree of stunning, depending on the condition of the poultry upon arrival at the slaughterhouse and unloading for slaughter. SUMMARY OF THE INVENTION [0011] On this background it is the purpose of the invention to provide an improved method for gas stunning of poultry for slaughter, which method by means of simple provisions and means makes it possible to optimize the stunning by being able to allow for all the parameters mentioned above. [0012] The method according to the invention adjusts the influence of the gas for stunning of the animals by reducing or prolonging the conveying time and/or the active conveying route length of the animals on said conveyors through the stunning chamber. It has surprisingly appeared that by means of such simple provisions it is possible to optimize the stunning, while at the same time allowing for all the parameters mentioned. As an especially important thing it should be mentioned that at the same time it is possible to consider the welfare of the animals by observing the stunning condition of the animals before they reach the actual slaughter. If the stunning condition of the animals is not optimum, it will be easy to prolong or reduce the conveying time and/or the conveying route through the stunning chamber. [0013] An optimum condition of stunning will be that the animals are so well stunned that with certainty they do not awaken before they reach slaughtering. On the other hand it is also important that the animals do not die in stunning because it is important that the pumping function of the heart is maintained in order to contribute to the pumping out of blood when the necks of the animals are cut in the actual slaughter. [0014] Appropriately, by the invention a method is used by which the adjustment of the conveying time through the stunning chamber is effected by increasing or reducing the speed of the said conveyors. [0015] By the method according to the invention it may furthermore be advantageous that the adjustment of the conveying route through the stunning chamber is effected by reducing or prolonging the active conveyor runs of the respective conveyors. [0016] Furthermore, the method according to the invention may be modified such that the influence of the gas for stunning of the animals moreover is adjusted by varying the gas concentration at varying heights in the stunning chamber in that increasing gas concentration is applied in a direction downwards in the stunning chamber [0017] The invention furthermore relates to a system for gas stunning of poultry for slaughter comprising a substantially horizontal conveyor arranged for receiving and introducing poultry for slaughter to a gas-filled stunning chamber in which a downwards running conveyor is arranged, which conveyor is arranged for successively conveying the poultry downwards in the stunning chamber, and an upwards running conveyor arranged for successively conveying the poultry upwards and out of the stunning chamber, wherein the downwards running conveyor either has a conveyor having a downwards running course and a horizontal course, the downwards running conveyor, comprising mutually interacting telescopic members for adjustment of the active conveying route length, or are constituted by a helical conveyor interacting with a horizontal, telescopic conveyor. [0018] Preferably, the system according to the invention is provided such that the upwards running conveyor is constituted by conveyors having mutually interacting telescopic members, namely, a horizontal conveyor and an upwards running conveyor having a slanting course. [0019] Appropriately, the system according to the invention is provided such that the stunning chamber is divided into a number of horizontal zones, for example, a lower zone having a gas concentration (C0 2 ) of approximately 45-51%, an intermediate zone having a gas concentration (C0 2 ) of 25% to approximately 32%-46%, and an upper zone having a gas concentration (C0 2 ) of 5% to approximately 8%-10%. Sensors are provided with the upper zone limits for monitoring and control respectively of the gas concentration in the zones. The actual gas concentration percentage varies a great deal in connection with shift between stopping and operation, and upon a changed rate of motion of the. This variation in gas concentration has relatively small influence on the stunning result, whereas the time of presence, especially in the first zone, and the total time of presence in the stunning chamber have great influence. [0020] The system according to the invention is preferably provided such that it comprises a PLC control system for controlling a number of mutually dependent mechanical parameters, for example speed of conveyors, setting (17.6 meters/minute), number of birds (chickens) on conveyors, speed of slaughtering line, setting (148 birds/minute). [0021] If one setting is changed, the other settings are changed correspondingly, for example if the birds are larger, it means that there are fewer animals on the conveyors, but the speed of the slaughtering line continues to be the same. Consequently it becomes necessary to convey more animals per minute through the stunning chamber, that is, increased conveying speed. At the same time each individual bird is larger which is why it is stunned for a longer time, is longer conveying time and conveying route length respectively are required. through the stunning chamber. BRIEF DESCRIPTION OF THE DRAWINGS [0022] The invention is explained in more detail below with reference to the drawing in which [0023] FIG. 1 shows a longitudinal sectional view, partially in section, through an embodiment of a system for gas stunning of poultry for slaughter according to the invention; and [0024] FIG. 2 shows a top view of another embodiment of a system for gas stunning of poultry for slaughter. DETAILED DESCRIPTION OF THE INVENTION [0025] The system 2 shown in FIG. 1 for gas stunning of poultry for slaughter comprises a supply conveyor (not shown) for supply of poultry, which for example arrives at the slaughterhouse by truck, and which have been taken out of any transport crates before they arc transferred to the stunning system 2 . The poultry 4 is transferred successively to a stunning conveyor 6 which actually is a system of endless conveyors having a number of sections running downwards into a stunning chamber 8 , the major part of which is a concrete pit 10 lowered in relation to the floor level, which chamber is filled with stunning gas, for example CO2 with varying gas concentrations, namely, an upper or first zone 12 having a gas concentration of approximately 5% to approximately 8%-10%, an intermediate or second zone 14 having a gas concentration of approximately 25% to approximately 32%-46%, and a lower and third zone 16 having a gas concentration of approximately 45-51%. [0026] The gas concentration in the zones 12 , 14 , 16 can be further varied according to requirements, for example in relation to bird size or type. The gas concentration in the respective zones is controlled by suitable gas sensors and an actually known gas filling/control system with filling valves. [0027] From the stunning conveyor 6 , the poultry 4 is successively conveyed into a downwards running conveyor section 18 , which continues into a horizontal conveyor section 20 , whose active length can be varied by means of a telescopic system 22 . From the conveyor section 20 the poultry 4 is transferred to a downwards running conveyor section 24 whose active length can be varied by means of a telescopic system 26 which interacts with the telescopic system 22 for the conveyor section 20 . From the conveyor section 24 the poultry 4 , which by now is stunned, is conveyed onto a horizontally running conveyor 28 whose active conveying route length also can be varied by means of a telescopic system 30 . The stunned poultry 4 is then conveyed upwards and out from the stunning chamber 8 by an upwards running conveyor 32 , which, and for being able to interact with the conveyor 26 , also comprises a telescopic system 34 for variation of the active conveying route length of the conveyor 28 . [0028] From the conveyor 32 the stunned poultry are transferred to an external conveyor for being shackled on a slaughtering line. Shortly after the stunned chickens have been shackled by their legs in slaughter shackles, the chickens pass a slaughter location where their necks are cut so that the chickens bleed out as a result of the pumping function of their hearts still being intact if the gas stunning is optimum. [0029] If it is determined that the gas stunning either is too great, that is the chickens are already dead, the stunning must be adjusted by shortening the conveying route and/or the conveying time through the stunning chamber so that the stunning becomes less. If the chickens on the contrary show signs of too little stunning, the stunning must likewise be adjusted so that the conveying route and/or the conveying time through the stunning chamber is increased. [0030] In both situations, adjustment can be effected by reducing or prolonging the conveying time and/or by changing the active conveying route lengths of the conveyors 20 , 24 , 28 , 32 by means of the telescopic systems 22 , 26 , 30 , 34 . [0031] Sensors in given locations ensure that the respective conveyors are in correct positions, for example for small, medium-sized, or large chickens. An important thing which also influences the stunning result is that the poultry 4 is stepped downwards, starting in a low gas concentration of Approximately 5%-10%. The step by step downwards conveying ensures that the chickens upon starting and stopping lift their heads whereby they can freely breathe in the relatively low gas concentration. This prevents the poultry from becoming stressed, and injuries are avoided. [0032] To reduce or prolong the conveying time through the stunning chamber 8 , it is of course also possible to adjust the speed of the respective conveyors. [0033] After the first part of the downwards movement, the poultry has “fallen asleep” and this continues further down where the gas concentration is max. 50% at the bottom of the chamber. Hereby it is ensured that the chickens will not wake up before their necks have been cut and they have bled out. Furthermore, regarding safety, it is an advantage to lower the stunning chamber below the floor level so that gas leakage above height of the head an operator is avoided. [0034] The system 36 outlined in FIG. 2 comprises a stunning chamber 38 which like the system 2 (FIG. I) described above comprises a concrete pit 40 lowered in relation to floor level. After unloading, poultry is transferred to the stunning chamber 38 via a horizontal supply conveyor 42 delivering the birds to a downwards running helical conveyor 44 which at the bottom of the stunning chamber 38 again delivers the now stunned birds to a horizontal, telescopic conveyor 46 from which the stunned birds are transferred to an upwards running conveyor 48 which conveys the stunned birds upwards and out of the stunning chamber 38 for further conveyance to shackling on a slaughtering line, etc. [0035] The conveyors 42 , 44 , 46 have relatively large widths of for example Approximately 800 mm each, that is at a given speed, the capacity of these conveyors is large. In a simple manner the width of the conveyors 42 , 44 , 46 and thus their capacity can be reduced by means of laterally displaceable walls 43 , 45 , 47 . By this lateral displacement of the walls 43 , 45 , 47 the conveying route length is moreover varied in that the length of the helical conveyor is prolonged by forcing the poultry outwards in the curve and oppositely, by forcing the poultry inwards in the curve. [0036] Alternatively, the capacity of the cooperating conveyors 42 , 44 , 46 can be varied by varying the conveying speed or the conveying route length in that the number of “twists” of the helical conveyor 44 can be adjusted to the actual conveying need, just as the active length of the telescopic conveyor 46 can be varied. In this connection, it should be mentioned that the slanting position of the upwards running conveyor also can be adjusted. The upwards running conveyor is provided with transversely positioned carriers 50 which, if the conveyor 48 has a very steep course, can be replaced by cups so that the stunned birds will surely be conveyed upwards and out of the stunning chamber 38 .
A method for gas stunning of poultry for slaughter is in which the poultry arrives at the poultry slaughterhouse, for example, in transport crates, where the poultry is subjected to gas after the poultry have been taken out of the transport crates, and where the poultry are conveyed by conveyors ( 18, 20, 24, 32 ) successively through a stunning chamber ( 8 ). The influence of the stunning gas for stunning of the poultry is adjusted in the stunning chamber by reducing or increasing by adjusting an effective length of at least one conveyor in the stunning chamber ( 8 ).
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a divisional application of U.S. Ser.", "No. 10/543,187, filed Jul. 21, 2005, and the entire disclosure of which is hereby incorporated by reference.", "FIELD OF THE INVENTION [0002] The present invention relates to a method for gas stunning of poultry.", "BACKGROUND OF THE INVENTION [0003] Over time, many different methods have been proposed for gas stunning of poultry arriving at the poultry slaughterhouse in transport crates, with no remarkable success.", "In practice however, several parameters must be considered in order to be able to optimize a method for gas stunning of poultry for slaughter.", "[0004] To optimize the method, the following parameters must be considered: Conveying speed (capacity of the system).", "Size and number of birds in the transport crates.", "The physical condition of the poultry flock which is determined by continuously observing variations in stress condition or resistance of the poultry which are significant for determining the time necessary for stunning the poultry which further may vary because of conditions in broiler houses, temperatures, transport time, and waiting time in the slaughterhouse.", "[0008] To optimize the gas stunning it is furthermore necessary to be able to continuously consider all these parameters prior to and during gas stunning of the poultry supplies delivered to the slaughterhouse, and continuously apply the most advantageous parameters to achieve optimum gas stunning of the actual chicken flock at any time to be stunned and slaughtered, respectively.", "[0009] To optimize these parameters, different periods of stunning time can be applied, but variations in the gas concentration, and variations of gas concentration in the different sections of the conveying route must also be considered, dependent on the conveying route length and conveying route location in the stunning chamber.", "[0010] The gas concentration may be monitored and controlled by means of sensors having different locations, and a PLC control system.", "Adjustment of the stunning time and simultaneous variation of the gas concentration require a change in the previously used methods by which a given slaughtering capacity of number of birds per minute required a fixed conveying time through stunning chamber.", "A given rate of slaughtering (slaughtering capacity) will always be determined by other subsequent parameters that cannot be changed right away why they are maintained.", "Consequently it may furthermore be necessary to be able to change the degree of stunning, depending on the condition of the poultry upon arrival at the slaughterhouse and unloading for slaughter.", "SUMMARY OF THE INVENTION [0011] On this background it is the purpose of the invention to provide an improved method for gas stunning of poultry for slaughter, which method by means of simple provisions and means makes it possible to optimize the stunning by being able to allow for all the parameters mentioned above.", "[0012] The method according to the invention adjusts the influence of the gas for stunning of the animals by reducing or prolonging the conveying time and/or the active conveying route length of the animals on said conveyors through the stunning chamber.", "It has surprisingly appeared that by means of such simple provisions it is possible to optimize the stunning, while at the same time allowing for all the parameters mentioned.", "As an especially important thing it should be mentioned that at the same time it is possible to consider the welfare of the animals by observing the stunning condition of the animals before they reach the actual slaughter.", "If the stunning condition of the animals is not optimum, it will be easy to prolong or reduce the conveying time and/or the conveying route through the stunning chamber.", "[0013] An optimum condition of stunning will be that the animals are so well stunned that with certainty they do not awaken before they reach slaughtering.", "On the other hand it is also important that the animals do not die in stunning because it is important that the pumping function of the heart is maintained in order to contribute to the pumping out of blood when the necks of the animals are cut in the actual slaughter.", "[0014] Appropriately, by the invention a method is used by which the adjustment of the conveying time through the stunning chamber is effected by increasing or reducing the speed of the said conveyors.", "[0015] By the method according to the invention it may furthermore be advantageous that the adjustment of the conveying route through the stunning chamber is effected by reducing or prolonging the active conveyor runs of the respective conveyors.", "[0016] Furthermore, the method according to the invention may be modified such that the influence of the gas for stunning of the animals moreover is adjusted by varying the gas concentration at varying heights in the stunning chamber in that increasing gas concentration is applied in a direction downwards in the stunning chamber [0017] The invention furthermore relates to a system for gas stunning of poultry for slaughter comprising a substantially horizontal conveyor arranged for receiving and introducing poultry for slaughter to a gas-filled stunning chamber in which a downwards running conveyor is arranged, which conveyor is arranged for successively conveying the poultry downwards in the stunning chamber, and an upwards running conveyor arranged for successively conveying the poultry upwards and out of the stunning chamber, wherein the downwards running conveyor either has a conveyor having a downwards running course and a horizontal course, the downwards running conveyor, comprising mutually interacting telescopic members for adjustment of the active conveying route length, or are constituted by a helical conveyor interacting with a horizontal, telescopic conveyor.", "[0018] Preferably, the system according to the invention is provided such that the upwards running conveyor is constituted by conveyors having mutually interacting telescopic members, namely, a horizontal conveyor and an upwards running conveyor having a slanting course.", "[0019] Appropriately, the system according to the invention is provided such that the stunning chamber is divided into a number of horizontal zones, for example, a lower zone having a gas concentration (C0 2 ) of approximately 45-51%, an intermediate zone having a gas concentration (C0 2 ) of 25% to approximately 32%-46%, and an upper zone having a gas concentration (C0 2 ) of 5% to approximately 8%-10%.", "Sensors are provided with the upper zone limits for monitoring and control respectively of the gas concentration in the zones.", "The actual gas concentration percentage varies a great deal in connection with shift between stopping and operation, and upon a changed rate of motion of the.", "This variation in gas concentration has relatively small influence on the stunning result, whereas the time of presence, especially in the first zone, and the total time of presence in the stunning chamber have great influence.", "[0020] The system according to the invention is preferably provided such that it comprises a PLC control system for controlling a number of mutually dependent mechanical parameters, for example speed of conveyors, setting (17.6 meters/minute), number of birds (chickens) on conveyors, speed of slaughtering line, setting (148 birds/minute).", "[0021] If one setting is changed, the other settings are changed correspondingly, for example if the birds are larger, it means that there are fewer animals on the conveyors, but the speed of the slaughtering line continues to be the same.", "Consequently it becomes necessary to convey more animals per minute through the stunning chamber, that is, increased conveying speed.", "At the same time each individual bird is larger which is why it is stunned for a longer time, is longer conveying time and conveying route length respectively are required.", "through the stunning chamber.", "BRIEF DESCRIPTION OF THE DRAWINGS [0022] The invention is explained in more detail below with reference to the drawing in which [0023] FIG. 1 shows a longitudinal sectional view, partially in section, through an embodiment of a system for gas stunning of poultry for slaughter according to the invention;", "and [0024] FIG. 2 shows a top view of another embodiment of a system for gas stunning of poultry for slaughter.", "DETAILED DESCRIPTION OF THE INVENTION [0025] The system 2 shown in FIG. 1 for gas stunning of poultry for slaughter comprises a supply conveyor (not shown) for supply of poultry, which for example arrives at the slaughterhouse by truck, and which have been taken out of any transport crates before they arc transferred to the stunning system 2 .", "The poultry 4 is transferred successively to a stunning conveyor 6 which actually is a system of endless conveyors having a number of sections running downwards into a stunning chamber 8 , the major part of which is a concrete pit 10 lowered in relation to the floor level, which chamber is filled with stunning gas, for example CO2 with varying gas concentrations, namely, an upper or first zone 12 having a gas concentration of approximately 5% to approximately 8%-10%, an intermediate or second zone 14 having a gas concentration of approximately 25% to approximately 32%-46%, and a lower and third zone 16 having a gas concentration of approximately 45-51%.", "[0026] The gas concentration in the zones 12 , 14 , 16 can be further varied according to requirements, for example in relation to bird size or type.", "The gas concentration in the respective zones is controlled by suitable gas sensors and an actually known gas filling/control system with filling valves.", "[0027] From the stunning conveyor 6 , the poultry 4 is successively conveyed into a downwards running conveyor section 18 , which continues into a horizontal conveyor section 20 , whose active length can be varied by means of a telescopic system 22 .", "From the conveyor section 20 the poultry 4 is transferred to a downwards running conveyor section 24 whose active length can be varied by means of a telescopic system 26 which interacts with the telescopic system 22 for the conveyor section 20 .", "From the conveyor section 24 the poultry 4 , which by now is stunned, is conveyed onto a horizontally running conveyor 28 whose active conveying route length also can be varied by means of a telescopic system 30 .", "The stunned poultry 4 is then conveyed upwards and out from the stunning chamber 8 by an upwards running conveyor 32 , which, and for being able to interact with the conveyor 26 , also comprises a telescopic system 34 for variation of the active conveying route length of the conveyor 28 .", "[0028] From the conveyor 32 the stunned poultry are transferred to an external conveyor for being shackled on a slaughtering line.", "Shortly after the stunned chickens have been shackled by their legs in slaughter shackles, the chickens pass a slaughter location where their necks are cut so that the chickens bleed out as a result of the pumping function of their hearts still being intact if the gas stunning is optimum.", "[0029] If it is determined that the gas stunning either is too great, that is the chickens are already dead, the stunning must be adjusted by shortening the conveying route and/or the conveying time through the stunning chamber so that the stunning becomes less.", "If the chickens on the contrary show signs of too little stunning, the stunning must likewise be adjusted so that the conveying route and/or the conveying time through the stunning chamber is increased.", "[0030] In both situations, adjustment can be effected by reducing or prolonging the conveying time and/or by changing the active conveying route lengths of the conveyors 20 , 24 , 28 , 32 by means of the telescopic systems 22 , 26 , 30 , 34 .", "[0031] Sensors in given locations ensure that the respective conveyors are in correct positions, for example for small, medium-sized, or large chickens.", "An important thing which also influences the stunning result is that the poultry 4 is stepped downwards, starting in a low gas concentration of Approximately 5%-10%.", "The step by step downwards conveying ensures that the chickens upon starting and stopping lift their heads whereby they can freely breathe in the relatively low gas concentration.", "This prevents the poultry from becoming stressed, and injuries are avoided.", "[0032] To reduce or prolong the conveying time through the stunning chamber 8 , it is of course also possible to adjust the speed of the respective conveyors.", "[0033] After the first part of the downwards movement, the poultry has “fallen asleep”", "and this continues further down where the gas concentration is max.", "50% at the bottom of the chamber.", "Hereby it is ensured that the chickens will not wake up before their necks have been cut and they have bled out.", "Furthermore, regarding safety, it is an advantage to lower the stunning chamber below the floor level so that gas leakage above height of the head an operator is avoided.", "[0034] The system 36 outlined in FIG. 2 comprises a stunning chamber 38 which like the system 2 (FIG.", "I) described above comprises a concrete pit 40 lowered in relation to floor level.", "After unloading, poultry is transferred to the stunning chamber 38 via a horizontal supply conveyor 42 delivering the birds to a downwards running helical conveyor 44 which at the bottom of the stunning chamber 38 again delivers the now stunned birds to a horizontal, telescopic conveyor 46 from which the stunned birds are transferred to an upwards running conveyor 48 which conveys the stunned birds upwards and out of the stunning chamber 38 for further conveyance to shackling on a slaughtering line, etc.", "[0035] The conveyors 42 , 44 , 46 have relatively large widths of for example Approximately 800 mm each, that is at a given speed, the capacity of these conveyors is large.", "In a simple manner the width of the conveyors 42 , 44 , 46 and thus their capacity can be reduced by means of laterally displaceable walls 43 , 45 , 47 .", "By this lateral displacement of the walls 43 , 45 , 47 the conveying route length is moreover varied in that the length of the helical conveyor is prolonged by forcing the poultry outwards in the curve and oppositely, by forcing the poultry inwards in the curve.", "[0036] Alternatively, the capacity of the cooperating conveyors 42 , 44 , 46 can be varied by varying the conveying speed or the conveying route length in that the number of “twists”", "of the helical conveyor 44 can be adjusted to the actual conveying need, just as the active length of the telescopic conveyor 46 can be varied.", "In this connection, it should be mentioned that the slanting position of the upwards running conveyor also can be adjusted.", "The upwards running conveyor is provided with transversely positioned carriers 50 which, if the conveyor 48 has a very steep course, can be replaced by cups so that the stunned birds will surely be conveyed upwards and out of the stunning chamber 38 ." ]
SUMMARY OF THE INVENTION The invention herein relates to a purse split insert for insertion in a purse having two separated compartments as well as in a purse having a single compartment. First insert means is provided having an exterior wall, an interior wall and opposing collapsible end walls. The exterior and interior walls have lower edges thereon and are joined together at the lower edges. Further, the first insert means has opposing sides which are connected by the opposing collapsible end walls which extend therebetween and thereby form an upper opening in the first insert means. Inside and outside surfaces are present on the first insert means exterior and interior walls. A plurality of flexible sheet-like members have lateral and lower peripheral edges and lie alongside and adjacent to portions of the exterior wall inside and outside and the interior wall inside surfaces. Means is provided for attaching the flexible sheet-like members at the lateral and lower peripheral edges to the adjacent portions of the exterior wall inside and outside and the interior wall inside surfaces to form a first plurality of upwardly opening article receiving pockets which are accessible at the first insert means exterior wall outside surface as well as through the first insert means upper opening. Second insert means has an exterior wall, an interior wall and opposing collapsible end walls. The latter exterior and interior wall have lower edges thereon and they are joined therealong. Further, the exterior and interior walls have opposing sides which are connected by the last mentioned opposing collapsible end walls to thereby form an upper opening in the second insert means. Inside and outside surfaces are present on the second insert means exterior and interior walls. A plurality of flexible sheet-like members having lateral and lower peripheral edges lie alongside and adjacent to portions of the exterior wall inside and outside and the interior wall inside surfaces. Means is provided for attaching the lateral and lower peripheral edges to the adjacent portions of the exterior wall inside and outside and the interior wall inside surfaces to thereby form a second plurality of upwardly opening article receiving pockets which are accessible at the second insert means exterior wall outside surface as well as through the second insert means upper opening. Releasable means is provided for attaching the first insert means interior wall outside surface to the second insert means interior wall outside surface. As a result, engagement of the releasable means facilitates insertion of the purse split insert in the purse having a single compartment and release thereof facilitates insertion in the purse having two separated compartments. A purse split insert is disclosed which is insertable into first and second purse compartments within a split compartment purse and into a sole compartment within a single compartment purse. A first purse insert has a first exterior wall which has a lower edge and opposing lateral edges. A first interior wall is present on the first purse insert wherein the first interior wall has a lower edge and opposing lateral edges. A first pair of expandable opposing end walls is also present in the first purse insert. The first exterior and interior walls are joined at the lower edge and the first pair of expandable opposing end walls are attached to and extend between the first exterior and interior walls at the opposing lateral edges so that an upper opening is formed in the first purse insert. A second purse insert has a second exterior wall which also has a lower edge and opposing lateral edges. A second interior wall is present on the second purse insert wherein the second interior wall also has a lower edge and opposing lateral edges. A second pair of expandable opposing end walls is also present on the second purse insert. The second exterior and interior walls are joined at the lower edges and the second pair of expandable opposing end walls are attached to and extend between the second exterior and interior walls at the opposing lateral edges. In this fashion an upper opening is formed as well in the second purse insert. Releasable means are provided for attaching the first interior wall to the second interior wall so that the first and second purse inserts are selectably joined together and separated for insertion within a single compartment purse and within a split compartment purse, respectively. A purse split insert is provided for placement as separate inserts within separate purse compartments in a split compartment purse and as a unitary insert within a single compartment in a single compartment purse. A first folded continuous member has opposing lateral sides and ends positioned in spaced side by side relationship. First means is provided for joining the opposing lateral edges whereby a first upper opening is formed between the first folded continuous member spaced ends. A second folded continuous member is provided having opposing lateral edges and ends positioned in spaced side by side relationship. Further, second means is provided for joining the opposing lateral edges, whereby a second upper opening is formed between the second folded continuous member spaced ends. Releasable means is provided for attaching the first and second folded continuous members together so that the first and second upper openings are in adjacent side by side relationship. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section through a split compartment purse showing the purse split inserts of the present invention in place. FIG. 2 is a section through a single compartment purse showing the purse split insert of the present invention in place. FIG. 3 is an end view of one insert in the purse split insert. FIG. 4 is an end view of another insert in the purse split insert. FIG. 5 is an isometric of the purse split insert of FIG. 3. FIG. 6 is a section along the line 6--6 of FIG. 3. FIG. 7 is a section along the line 7--7 of FIG. 4. FIG. 8 is a section along the line 8--8 of FIG. 4. FIG. 9 is an isometric of the purse split insert of FIG. 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS Ladies' purses are generally coordinated with other articles of ladies' dress, whereby it is not uncommon for several purses to be included in a lady's wardrobe. It therefore becomes necessary to shift articles commonly carried in a purse to a different purse when a change in attire requires it. The invention to be described herein is intended to facilitate the shifting of commonly carried articles from one purse to another purse. With reference to FIG. 1, a split compartment purse 10 is shown in section wherein the purse has an outer wall 11, a pair of end walls (one of which is shown as item 12 in the section of FIG. 1), a bottom wall 13 and an opposing wall 14, thereby creating an upper opening in the purse 10. A closure flap 16 extends from the upper portion of the opposing wall 14 having one portion of a snap fastener 17 mounted on the inside surface thereof. The closure flap 16, when placed over the upper opening shown in the purse 10, brings the portion 17 of the snap fastener into contact with a mating portion 18 of the fastener for securing the closure flap in place over the upper opening. A carrying strap 19 for the hand, arm or shoulder is shown extending from the end wall 12 in FIG. 1. A separator wall 21 is shown inside the purse 10 which separates the interior of the purse into two compartments shown as 10a and 10b in FIG. 1. A left purse split insert 22 is seen within the compartment 10a and a right purse split insert 23 is shown within the compartment 10b of split purse 10. It may be seen in FIG. 1 that the split inserts 22 and 23 are separated from one another by the separator wall 21. Turning to FIG. 2, a purse 24 is shown having a wall 26, a pair of end walls (one of which is shown in the section of FIG. 2 as item 27), and a bottom wall 28. An opposing wall 29 is shown, from the upper portion of which extends a closure flap 31. One portion of a snap 32 (or other fastening means) is shown on the inner surface of the closure flap 31 so that the closure flap may be positioned over the upper opening shown in the purse 24 and come into engagement with a mating part 33 of the snap mounted on the wall 26 of the purse 24. Again, a strap 34 is shown for carrying the purse 24 by hand, over the arm or over the shoulder. The purse split inserts 22 and 23 are seen within the single compartment in the purse 24 in contact with one another along one wall thereof and fastened together in a fashion and by means which will be hereinafter described . One portion of the purse split insert described herein is seen in FIG. 3 as the insert 22. Insert 22 has an exterior wall 36 and an interior wall 37. The exterior and internal walls 36 and 37 run into and out of the paper as seen in FIG. 3, having lateral edges, one of which is visible in FIG. 3. Expandable/collapsible end walls, one of which is shown at 38 in FIG. 3, extend between the opposing lateral edges of exterior and interior walls 36 and 37 of insert 22. Consequently, an upper opening is formed in insert 22 which is selectively opened and closed by moving the upper reaches of walls 36 and 37 toward and away from each other. The end walls, represented by item 38, are made of a relatively flexible fabric, while the exterior and interior walls 36 and 37, respectively, are fabricated from a stiffer fabric. Mating fastener pairs 39a and 39b are positioned on the inside surfaces of the upper reaches of walls 36 and 37 so that the upper opening in the insert 22 is held in a closed position by the mating fastener pairs when the upper ends of the walls 36 and 37 are moved together. Turning now to FIG. 4 of the drawings, the purse split insert 24 is seen having an interior wall 41, an exterior wall 42, and expandable/collapsible end walls, one of which is shown at 43 in FIG. 4. As described in connection with insert 22, the walls 41 and 42 of insert 23 are fabricated from a relatively stiff material, while the end walls represented by item 43 are made from a thinner material with less stiffness. As a result, the interior and exterior walls 41 and 42, respectively, of insert 23 may be moved together or spread apart to vary the size of an upper opening therein. Once again, when the upper portion of the internal and external walls of the insert 23 are moved together until they are in contact, pairs of mating fasteners shown as items 44a and 44b are engaged to maintain closure of the upper opening. Both of the inserts 22 and 23, as shown in FIGS. 3 and 4, display joinder of the external and internal walls 36 and 37 of insert 22 and the external and internal walls 42 and 41 of the insert 23 at the lower portions thereof. The exterior and interior walls of the inserts 22 and 23 are perceived in one form to be fabricated of a continuous wall member which extends from the upper portion of the interior wall past the lower portions of the walls to the upper portion of the exterior wall. In this fashion, the exterior and interior walls of each of the inserts are formed by a folded continuous member, with the ends of the member in spaced apart relation when the insert upper opening is opened. Alternatively, each of the interior and exterior walls of each insert may be fabricated from separate wall members having lower edges which are joined together, as by sewing, to form interior and exterior wall combinations as shown in FIGS. 3 and 4. In FIG. 3, at an upper position and at a lower position on the interior wall 37 a portion of a fastener 46 such as a strip of Velcro™ is seen affixed to the internal wall. As seen in FIG. 4, in corresponding upper and lower positions on the interior wall 41, mating portions 47 for the fastener portion 46 are seen affixed to the interior wall. The fastener portions 46 and 47 could as well be snaps or any other suitable releasable fastening means. In this fashion, the interior walls 37 and 41 of inserts 22 and 23, respectively, when placed in contact are held in side by side position by the mating features of the fastener portions 46 and 47. It may be seen that when the mating portions of the fasteners 46 and 47 are engaged, the purse split insert portions 22 and 23 are held together by the fasteners and the unitary combination of the purse split insert is insertable within the single compartment of purse 24 as seen in FIG. 2. When the purse split insert of the present invention is to be used in a split compartment purse such as purse 10 in FIG. 1, the fastener portions 46 and 47 seen in FIGS. 3 and 4 are released and the inserts 22 and 23 are individually placed within the separated compartments 10a and 10b, respectively, as shown in FIG. 1. It should be noted that in FIGS. 1 and 2 the inserts are shown with the upper opening fasteners 39a/39b and 44a/44b engaged so that the upper openings in each of the inserts 22 and 23 are closed. Turning now to FIG. 5 in the drawings, an isometric of the insert 22 is shown. The inside surface of interior wall 37 is designated 37b in FIG. 5. The inside surface 37b is divided into two halves by a sewn member 45 attached to the inside surface. A pair of slant top pockets 50 and 48 are formed between the sewn member 45 and the collapsible/expandable end wall designated 38b in FIG. 5. The pockets 50 and 48 occupy the left side of the inside surface 37bin FIG. 5 and are formed by sewing the lateral and lower peripheral edges of a piece of sheet-like fabric in place leaving the upper peripheral edge open. In this fashion upper openings 50a and 48a are provided in the pockets 50 and 48. On the right side of the inside surface 37b of interior wall 37 as seen in FIG. 5, a plurality of sheet-like pieces of fabric are sewn between the sewn member 45 and the expandable/collapsible end wall 38 at stepped heights on the inside surface. The number of sheet-like members 49a, 49b, 49c and 49d are also sewn at the lower peripheral edges to the inside surface 37b to form upwardly opening pockets for receiving items such as credit cards, etc. The outside surface of exterior wall 36 as seen in FIG. 5 has sheet-like members 51, 52 and 53 sewn thereto at the lateral and lower peripheral edges thereof to form respectively a slant top pocket having an opening 51a, a pen or other tubular article receiving pocket having an upper opening 52a, and an additional pocket having an upper opening 53a. FIG. 6 shows the inside surface 36a of exterior wall 36. The portions of the upper opening closure fasteners 39a are shown near the upper edge of the inner surface 36a. A strip of bias tape 54 is seen running down the lateral edges of the exterior wall 36 in FIG. 6 which when sewn in place along the lateral edges fixes the edges of the collapsible/expandable end walls 38 and 38b to the inside surface 36a of the exterior wall 36 at either lateral edge thereof. Further, a sewing operation at the lateral edges of exterior wall 36 secures one edge of slant top pockets 56 and 57 to the inside surface 36a of exterior wall 36. The opposing edges of the slant top pockets are secured to the inside surface 36a by a sewn member 58 running from the upper to the lower portion of the inside surface 36a. The slant top pockets 56 and 57 have upper openings as shown at 56a and 57a. FIG. 7 shows the outside surface of interior wall 41 and the mating portions 47 of the fastening combination 46/47 which affixes inserts 22 and 23 together in releasable fashion. It should be noted in FIG. 7 that the fastener portions 47 are depicted as Velcro™ strips. Velcro™ is a known "loop and hook" type fastener. The fastener portions could as readily be portions of snap type fasteners. In such a case a corresponding pattern of matching portions of snap type fasteners would be affixed to the outside surface of interior wall 37 in insert 22. FIG. 7 further shows a bias tape 61, similar to bias tape 54 in FIG. 6, which is sewn along the lateral edges of interior wall 41. FIG. 8 shows an inside surface 42a of the exterior wall 42 in purse split insert portion 23. The bias tape 61 strip is shown attached to the lateral edges of the exterior wall 42 serving to hold the expandable/collapsible wall 43 in place at one side of the insert and an opposing expandable/collapsible end wall 43b in place at the opposing side of the exterior wall 42. A sewn member 62 is shown extending from the upper edge of exterior wall inside surface 42a toward the lower edge thereof. Sheet-like members 63 and 64 have lateral and lower peripheral edges which are sewn, and therefore fixed to the inside surface 42a in conjunction with affixing the bias strips 61 in place and the affixing of the sewn member 62 in place. An upper slant top opening 63a provides access to an upwardly opening pocket thus formed by sheet-like member 63. In like fashion, an opening 64a provides access to a pocket thus formed by the sheet-like member 64. FIG. 9 is a perspective of the purse split insert portion 23 wherein the outside surface of exterior wall 42 and the inside surface 41a of interior wall 41 are visible. Expandable/collapsible end walls 43 and 43b are shown in partially closed or collapsed condition. Inside surface 41a has a sewn member 66 extending from the upper to the lower portions of the inside wall which serves to fix one edge of a sheet-like member 67 to the inside surface. The opposing side of the sheet-like member 67 is affixed to the inside surface 41a at the same time and by the same means for affixing the bias tape 61 and one edge of the expandable/collapsible wall 43b to the inside surface. The lower peripheral edge of the sheet-like member 67 is also fixed to the inside surface 41a as by sewing or through the use of an adhesive or the like. As a result, the sheet-like member 67 forms a pocket with an upper opening 67a therein. The opening 67a has a cover flap 68 attached to the inside surface 41a immediately thereabove. A fastener portion 69a is attached to the inside surface of the cover flap 68 which, when the flap 68 is lowered, is brought into contact with a mating fastener portion 69b attached to the outer surface of the sheet-like member 67. In this fashion a closure cover is provided for the opening 67a to allow articles to be deposited through the opening 67a into the pocket when the flap 68 is raised and to secure the articles within the pocket when the fastener portions 69a and 69b are brought into engagement. The fastener portions 69a and 69b may be closure devices such as snap fasteners as shown in FIG. 9. Further sheet-like members 71 and 72 are secured at the lateral edges thereof by the sewn member 66 and the bias tape 61 adjacent the expandable/collapsible end wall 43 on insert 23. The sheet-like members 71 and 72 have their lower peripheral edges fixed to the inside surface 41a in FIG. 9. As a consequence, openings 71a and 72a are provided which allow articles to be inserted therethrough and retained within pockets formed by the inside surface 41a and the sheet-like members 71 and 72. With further reference to FIG. 9, a fabric sheet 74 is depicted having its lateral edges secured to the outside surface of exterior wall 42 by the bias tape 61 at opposing lateral edges of the exterior wall. An upwardly-oriented opening 74a which extends across the width of the exterior wall 42 is thereby formed for receiving and storing larger flat articles therein. Another sewn member 76 extends from the opening 74a to the lower portion of the exterior wall 42. Sheet-like members 77 and 78 are fixed at their adjacent lateral peripheral edges by the sewn member 76 and at their opposing lateral edges by the bias tape 61 fixed to the opposing lateral edges of the insert 23. Sheet-like members 77 and 78 are secured across their lower peripheral edges to the outside surface of the exterior wall 42. A pair of pockets are thereby formed on the outer surface of the sheet-like member 74 having upwardly extending openings 77a and 78a therein. It may be seen from the foregoing that a purse split insert has been disclosed which is useful in split compartment or single compartment purses and which readily conveys articles generally contained within a purse from one purse to another regardless of purse type. Although the best mode contemplated for carrying out the present invention has been shown and described herein, it will be understood that modification and variation may be made without departing from what is regarded to be the subject matter of the invention.
A split insert pair for a purse is made of fabric which is stiffer at the outside walls and less stiff at the end walls and which has an upper opening which is capable of either being opened wide or held in closed position by fasteners located on opposite sides of the upper opening. Various upwardly opening pockets are situated on the inside and outside surfaces of the insert walls to receive the usual articles carried in a purse. An outside wall on each of the inserts of the pair is provided with matching patterns of releasable fasteners, so the pair of inserts is useable as a unitary joined pair or as separate inserts which may be placed in separate purse compartments.
Identify the most important aspect in the document and summarize the concept accordingly.
[ "SUMMARY OF THE INVENTION The invention herein relates to a purse split insert for insertion in a purse having two separated compartments as well as in a purse having a single compartment.", "First insert means is provided having an exterior wall, an interior wall and opposing collapsible end walls.", "The exterior and interior walls have lower edges thereon and are joined together at the lower edges.", "Further, the first insert means has opposing sides which are connected by the opposing collapsible end walls which extend therebetween and thereby form an upper opening in the first insert means.", "Inside and outside surfaces are present on the first insert means exterior and interior walls.", "A plurality of flexible sheet-like members have lateral and lower peripheral edges and lie alongside and adjacent to portions of the exterior wall inside and outside and the interior wall inside surfaces.", "Means is provided for attaching the flexible sheet-like members at the lateral and lower peripheral edges to the adjacent portions of the exterior wall inside and outside and the interior wall inside surfaces to form a first plurality of upwardly opening article receiving pockets which are accessible at the first insert means exterior wall outside surface as well as through the first insert means upper opening.", "Second insert means has an exterior wall, an interior wall and opposing collapsible end walls.", "The latter exterior and interior wall have lower edges thereon and they are joined therealong.", "Further, the exterior and interior walls have opposing sides which are connected by the last mentioned opposing collapsible end walls to thereby form an upper opening in the second insert means.", "Inside and outside surfaces are present on the second insert means exterior and interior walls.", "A plurality of flexible sheet-like members having lateral and lower peripheral edges lie alongside and adjacent to portions of the exterior wall inside and outside and the interior wall inside surfaces.", "Means is provided for attaching the lateral and lower peripheral edges to the adjacent portions of the exterior wall inside and outside and the interior wall inside surfaces to thereby form a second plurality of upwardly opening article receiving pockets which are accessible at the second insert means exterior wall outside surface as well as through the second insert means upper opening.", "Releasable means is provided for attaching the first insert means interior wall outside surface to the second insert means interior wall outside surface.", "As a result, engagement of the releasable means facilitates insertion of the purse split insert in the purse having a single compartment and release thereof facilitates insertion in the purse having two separated compartments.", "A purse split insert is disclosed which is insertable into first and second purse compartments within a split compartment purse and into a sole compartment within a single compartment purse.", "A first purse insert has a first exterior wall which has a lower edge and opposing lateral edges.", "A first interior wall is present on the first purse insert wherein the first interior wall has a lower edge and opposing lateral edges.", "A first pair of expandable opposing end walls is also present in the first purse insert.", "The first exterior and interior walls are joined at the lower edge and the first pair of expandable opposing end walls are attached to and extend between the first exterior and interior walls at the opposing lateral edges so that an upper opening is formed in the first purse insert.", "A second purse insert has a second exterior wall which also has a lower edge and opposing lateral edges.", "A second interior wall is present on the second purse insert wherein the second interior wall also has a lower edge and opposing lateral edges.", "A second pair of expandable opposing end walls is also present on the second purse insert.", "The second exterior and interior walls are joined at the lower edges and the second pair of expandable opposing end walls are attached to and extend between the second exterior and interior walls at the opposing lateral edges.", "In this fashion an upper opening is formed as well in the second purse insert.", "Releasable means are provided for attaching the first interior wall to the second interior wall so that the first and second purse inserts are selectably joined together and separated for insertion within a single compartment purse and within a split compartment purse, respectively.", "A purse split insert is provided for placement as separate inserts within separate purse compartments in a split compartment purse and as a unitary insert within a single compartment in a single compartment purse.", "A first folded continuous member has opposing lateral sides and ends positioned in spaced side by side relationship.", "First means is provided for joining the opposing lateral edges whereby a first upper opening is formed between the first folded continuous member spaced ends.", "A second folded continuous member is provided having opposing lateral edges and ends positioned in spaced side by side relationship.", "Further, second means is provided for joining the opposing lateral edges, whereby a second upper opening is formed between the second folded continuous member spaced ends.", "Releasable means is provided for attaching the first and second folded continuous members together so that the first and second upper openings are in adjacent side by side relationship.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a section through a split compartment purse showing the purse split inserts of the present invention in place.", "FIG. 2 is a section through a single compartment purse showing the purse split insert of the present invention in place.", "FIG. 3 is an end view of one insert in the purse split insert.", "FIG. 4 is an end view of another insert in the purse split insert.", "FIG. 5 is an isometric of the purse split insert of FIG. 3. FIG. 6 is a section along the line 6--6 of FIG. 3. FIG. 7 is a section along the line 7--7 of FIG. 4. FIG. 8 is a section along the line 8--8 of FIG. 4. FIG. 9 is an isometric of the purse split insert of FIG. 4. DESCRIPTION OF THE PREFERRED EMBODIMENTS Ladies'", "purses are generally coordinated with other articles of ladies'", "dress, whereby it is not uncommon for several purses to be included in a lady's wardrobe.", "It therefore becomes necessary to shift articles commonly carried in a purse to a different purse when a change in attire requires it.", "The invention to be described herein is intended to facilitate the shifting of commonly carried articles from one purse to another purse.", "With reference to FIG. 1, a split compartment purse 10 is shown in section wherein the purse has an outer wall 11, a pair of end walls (one of which is shown as item 12 in the section of FIG. 1), a bottom wall 13 and an opposing wall 14, thereby creating an upper opening in the purse 10.", "A closure flap 16 extends from the upper portion of the opposing wall 14 having one portion of a snap fastener 17 mounted on the inside surface thereof.", "The closure flap 16, when placed over the upper opening shown in the purse 10, brings the portion 17 of the snap fastener into contact with a mating portion 18 of the fastener for securing the closure flap in place over the upper opening.", "A carrying strap 19 for the hand, arm or shoulder is shown extending from the end wall 12 in FIG. 1. A separator wall 21 is shown inside the purse 10 which separates the interior of the purse into two compartments shown as 10a and 10b in FIG. 1. A left purse split insert 22 is seen within the compartment 10a and a right purse split insert 23 is shown within the compartment 10b of split purse 10.", "It may be seen in FIG. 1 that the split inserts 22 and 23 are separated from one another by the separator wall 21.", "Turning to FIG. 2, a purse 24 is shown having a wall 26, a pair of end walls (one of which is shown in the section of FIG. 2 as item 27), and a bottom wall 28.", "An opposing wall 29 is shown, from the upper portion of which extends a closure flap 31.", "One portion of a snap 32 (or other fastening means) is shown on the inner surface of the closure flap 31 so that the closure flap may be positioned over the upper opening shown in the purse 24 and come into engagement with a mating part 33 of the snap mounted on the wall 26 of the purse 24.", "Again, a strap 34 is shown for carrying the purse 24 by hand, over the arm or over the shoulder.", "The purse split inserts 22 and 23 are seen within the single compartment in the purse 24 in contact with one another along one wall thereof and fastened together in a fashion and by means which will be hereinafter described .", "One portion of the purse split insert described herein is seen in FIG. 3 as the insert 22.", "Insert 22 has an exterior wall 36 and an interior wall 37.", "The exterior and internal walls 36 and 37 run into and out of the paper as seen in FIG. 3, having lateral edges, one of which is visible in FIG. 3. Expandable/collapsible end walls, one of which is shown at 38 in FIG. 3, extend between the opposing lateral edges of exterior and interior walls 36 and 37 of insert 22.", "Consequently, an upper opening is formed in insert 22 which is selectively opened and closed by moving the upper reaches of walls 36 and 37 toward and away from each other.", "The end walls, represented by item 38, are made of a relatively flexible fabric, while the exterior and interior walls 36 and 37, respectively, are fabricated from a stiffer fabric.", "Mating fastener pairs 39a and 39b are positioned on the inside surfaces of the upper reaches of walls 36 and 37 so that the upper opening in the insert 22 is held in a closed position by the mating fastener pairs when the upper ends of the walls 36 and 37 are moved together.", "Turning now to FIG. 4 of the drawings, the purse split insert 24 is seen having an interior wall 41, an exterior wall 42, and expandable/collapsible end walls, one of which is shown at 43 in FIG. 4. As described in connection with insert 22, the walls 41 and 42 of insert 23 are fabricated from a relatively stiff material, while the end walls represented by item 43 are made from a thinner material with less stiffness.", "As a result, the interior and exterior walls 41 and 42, respectively, of insert 23 may be moved together or spread apart to vary the size of an upper opening therein.", "Once again, when the upper portion of the internal and external walls of the insert 23 are moved together until they are in contact, pairs of mating fasteners shown as items 44a and 44b are engaged to maintain closure of the upper opening.", "Both of the inserts 22 and 23, as shown in FIGS. 3 and 4, display joinder of the external and internal walls 36 and 37 of insert 22 and the external and internal walls 42 and 41 of the insert 23 at the lower portions thereof.", "The exterior and interior walls of the inserts 22 and 23 are perceived in one form to be fabricated of a continuous wall member which extends from the upper portion of the interior wall past the lower portions of the walls to the upper portion of the exterior wall.", "In this fashion, the exterior and interior walls of each of the inserts are formed by a folded continuous member, with the ends of the member in spaced apart relation when the insert upper opening is opened.", "Alternatively, each of the interior and exterior walls of each insert may be fabricated from separate wall members having lower edges which are joined together, as by sewing, to form interior and exterior wall combinations as shown in FIGS. 3 and 4.", "In FIG. 3, at an upper position and at a lower position on the interior wall 37 a portion of a fastener 46 such as a strip of Velcro™ is seen affixed to the internal wall.", "As seen in FIG. 4, in corresponding upper and lower positions on the interior wall 41, mating portions 47 for the fastener portion 46 are seen affixed to the interior wall.", "The fastener portions 46 and 47 could as well be snaps or any other suitable releasable fastening means.", "In this fashion, the interior walls 37 and 41 of inserts 22 and 23, respectively, when placed in contact are held in side by side position by the mating features of the fastener portions 46 and 47.", "It may be seen that when the mating portions of the fasteners 46 and 47 are engaged, the purse split insert portions 22 and 23 are held together by the fasteners and the unitary combination of the purse split insert is insertable within the single compartment of purse 24 as seen in FIG. 2. When the purse split insert of the present invention is to be used in a split compartment purse such as purse 10 in FIG. 1, the fastener portions 46 and 47 seen in FIGS. 3 and 4 are released and the inserts 22 and 23 are individually placed within the separated compartments 10a and 10b, respectively, as shown in FIG. 1. It should be noted that in FIGS. 1 and 2 the inserts are shown with the upper opening fasteners 39a/39b and 44a/44b engaged so that the upper openings in each of the inserts 22 and 23 are closed.", "Turning now to FIG. 5 in the drawings, an isometric of the insert 22 is shown.", "The inside surface of interior wall 37 is designated 37b in FIG. 5. The inside surface 37b is divided into two halves by a sewn member 45 attached to the inside surface.", "A pair of slant top pockets 50 and 48 are formed between the sewn member 45 and the collapsible/expandable end wall designated 38b in FIG. 5. The pockets 50 and 48 occupy the left side of the inside surface 37bin FIG. 5 and are formed by sewing the lateral and lower peripheral edges of a piece of sheet-like fabric in place leaving the upper peripheral edge open.", "In this fashion upper openings 50a and 48a are provided in the pockets 50 and 48.", "On the right side of the inside surface 37b of interior wall 37 as seen in FIG. 5, a plurality of sheet-like pieces of fabric are sewn between the sewn member 45 and the expandable/collapsible end wall 38 at stepped heights on the inside surface.", "The number of sheet-like members 49a, 49b, 49c and 49d are also sewn at the lower peripheral edges to the inside surface 37b to form upwardly opening pockets for receiving items such as credit cards, etc.", "The outside surface of exterior wall 36 as seen in FIG. 5 has sheet-like members 51, 52 and 53 sewn thereto at the lateral and lower peripheral edges thereof to form respectively a slant top pocket having an opening 51a, a pen or other tubular article receiving pocket having an upper opening 52a, and an additional pocket having an upper opening 53a.", "FIG. 6 shows the inside surface 36a of exterior wall 36.", "The portions of the upper opening closure fasteners 39a are shown near the upper edge of the inner surface 36a.", "A strip of bias tape 54 is seen running down the lateral edges of the exterior wall 36 in FIG. 6 which when sewn in place along the lateral edges fixes the edges of the collapsible/expandable end walls 38 and 38b to the inside surface 36a of the exterior wall 36 at either lateral edge thereof.", "Further, a sewing operation at the lateral edges of exterior wall 36 secures one edge of slant top pockets 56 and 57 to the inside surface 36a of exterior wall 36.", "The opposing edges of the slant top pockets are secured to the inside surface 36a by a sewn member 58 running from the upper to the lower portion of the inside surface 36a.", "The slant top pockets 56 and 57 have upper openings as shown at 56a and 57a.", "FIG. 7 shows the outside surface of interior wall 41 and the mating portions 47 of the fastening combination 46/47 which affixes inserts 22 and 23 together in releasable fashion.", "It should be noted in FIG. 7 that the fastener portions 47 are depicted as Velcro™ strips.", "Velcro™ is a known "loop and hook"", "type fastener.", "The fastener portions could as readily be portions of snap type fasteners.", "In such a case a corresponding pattern of matching portions of snap type fasteners would be affixed to the outside surface of interior wall 37 in insert 22.", "FIG. 7 further shows a bias tape 61, similar to bias tape 54 in FIG. 6, which is sewn along the lateral edges of interior wall 41.", "FIG. 8 shows an inside surface 42a of the exterior wall 42 in purse split insert portion 23.", "The bias tape 61 strip is shown attached to the lateral edges of the exterior wall 42 serving to hold the expandable/collapsible wall 43 in place at one side of the insert and an opposing expandable/collapsible end wall 43b in place at the opposing side of the exterior wall 42.", "A sewn member 62 is shown extending from the upper edge of exterior wall inside surface 42a toward the lower edge thereof.", "Sheet-like members 63 and 64 have lateral and lower peripheral edges which are sewn, and therefore fixed to the inside surface 42a in conjunction with affixing the bias strips 61 in place and the affixing of the sewn member 62 in place.", "An upper slant top opening 63a provides access to an upwardly opening pocket thus formed by sheet-like member 63.", "In like fashion, an opening 64a provides access to a pocket thus formed by the sheet-like member 64.", "FIG. 9 is a perspective of the purse split insert portion 23 wherein the outside surface of exterior wall 42 and the inside surface 41a of interior wall 41 are visible.", "Expandable/collapsible end walls 43 and 43b are shown in partially closed or collapsed condition.", "Inside surface 41a has a sewn member 66 extending from the upper to the lower portions of the inside wall which serves to fix one edge of a sheet-like member 67 to the inside surface.", "The opposing side of the sheet-like member 67 is affixed to the inside surface 41a at the same time and by the same means for affixing the bias tape 61 and one edge of the expandable/collapsible wall 43b to the inside surface.", "The lower peripheral edge of the sheet-like member 67 is also fixed to the inside surface 41a as by sewing or through the use of an adhesive or the like.", "As a result, the sheet-like member 67 forms a pocket with an upper opening 67a therein.", "The opening 67a has a cover flap 68 attached to the inside surface 41a immediately thereabove.", "A fastener portion 69a is attached to the inside surface of the cover flap 68 which, when the flap 68 is lowered, is brought into contact with a mating fastener portion 69b attached to the outer surface of the sheet-like member 67.", "In this fashion a closure cover is provided for the opening 67a to allow articles to be deposited through the opening 67a into the pocket when the flap 68 is raised and to secure the articles within the pocket when the fastener portions 69a and 69b are brought into engagement.", "The fastener portions 69a and 69b may be closure devices such as snap fasteners as shown in FIG. 9. Further sheet-like members 71 and 72 are secured at the lateral edges thereof by the sewn member 66 and the bias tape 61 adjacent the expandable/collapsible end wall 43 on insert 23.", "The sheet-like members 71 and 72 have their lower peripheral edges fixed to the inside surface 41a in FIG. 9. As a consequence, openings 71a and 72a are provided which allow articles to be inserted therethrough and retained within pockets formed by the inside surface 41a and the sheet-like members 71 and 72.", "With further reference to FIG. 9, a fabric sheet 74 is depicted having its lateral edges secured to the outside surface of exterior wall 42 by the bias tape 61 at opposing lateral edges of the exterior wall.", "An upwardly-oriented opening 74a which extends across the width of the exterior wall 42 is thereby formed for receiving and storing larger flat articles therein.", "Another sewn member 76 extends from the opening 74a to the lower portion of the exterior wall 42.", "Sheet-like members 77 and 78 are fixed at their adjacent lateral peripheral edges by the sewn member 76 and at their opposing lateral edges by the bias tape 61 fixed to the opposing lateral edges of the insert 23.", "Sheet-like members 77 and 78 are secured across their lower peripheral edges to the outside surface of the exterior wall 42.", "A pair of pockets are thereby formed on the outer surface of the sheet-like member 74 having upwardly extending openings 77a and 78a therein.", "It may be seen from the foregoing that a purse split insert has been disclosed which is useful in split compartment or single compartment purses and which readily conveys articles generally contained within a purse from one purse to another regardless of purse type.", "Although the best mode contemplated for carrying out the present invention has been shown and described herein, it will be understood that modification and variation may be made without departing from what is regarded to be the subject matter of the invention." ]
REFERENCE TO RELATED APPLICATION This is a divisional application of Ser. No. 07/311,402, filed Feb. 15, 1989 (now abandoned), which is a CIP application of Ser. No. 07/137,567, filed Dec. 24, 1987 (now abandoned) which is a CIP of Ser. No. 06/909,203, now U.S. Pat. No. 4,735,821. BACKGROUND OF THE INVENTION This invention relates to a capacitor for a semiconductor memory, and to a method in which a photo CVD process is carried out so that the deposition is effectively performed also on insides of depressions. There is broadly known and used a low pressure CVD method, a plasma CVD method, and a chemical vapor deposition method for semiconductor processing. In the semiconductor processing method, depressions such as a hole, a trench, a cave (a sub-surface re-entrant opening having surfaces out of line-of-sight) or so on are configured on whose surfaces are placed a product created by the CVD method to form a buried field insulating layer or an electric element such as a capacitance in the depression, or to fill an over-etching region in the form of a depression. When a formation of a layer on the depression is desired, it is inevitable that the thickness "ds" of the layer on an inner surface (depression) and the thickness "dt" of the layer on an upper surface result in dt/ds>1. One of the problems of researching to obtain a finely configured semiconductor in the VLSI field is how an inverse ratio, namely ds/dt, can be increased near 1. Further, in the case where the depth of a cave has a measure more than the measure of the opening of the cave, it was impossible to form a uniform layer throughout the inside of the cave. Such caves are formed, e.g., with a known trench method which can dig a cave of depth having a measure 3 to 5 times as large as the measure of the width of the opening thereof. Anyhow, existing methods are not suitable to perform a deposition in such a cave. Namely, according to an existing CVD method, atoms or molecules are deposited on a substrate in an excited condition which are diffused into vapor after being decomposed or after undergoing a reaction caused by thermal energy. The existing process can be performed effectively when it is carried out under negative pressure, since the active molecules have a relatively long mean free path in the vapor under a negative pressure, compared with that under the atmospheric pressure. For example, on a substrate with a trench of 2 micron meters in width and also in depth, a depression resulted in a layer 1 of micron meter thickness on the upper surface, a layer with at most a thickness of 0.7 micron meter on the side wall of the trench and a layer with the thickness of 0.6 micron meter on the bottom of the trench. In any case, a step coverage ds/dt is expected only up to about 0.7. According to another known method, step coverages are no more than that of the above method. Normally, ds/dt=0.3-0.5. A plasma enhanced CVD alone is comparable with the above LPCVD. Another problem associated with the prior art is as follows. When a surface having depressions is coated with an overlying layer, the top surface of the overlying layer inevitably becomes uneven. Some troubles are caused by the uneven surface. For example, when a multi-level interconnection is produced with intervening insulating films for isolating constituent electrode arrangements on different levels (as illustrated in FIGS. 8(A)-8(E)), the electrode arrangement (or pattern) overlying an uneven surface of the intervening insulating film may not be connected to the electrode pattern beneath the intervening insulating film. SUMMARY OF THE INVENTION This application is directed to a capacitor which can be used for finely densed capacitances formed on a semiconductor memory, and to a method for coating the side surface of a trench other than its bottom. The opening of the coating on the bottom can be used for forming a capacitance, a transistor, or so forth. The invention has been conceived on the basis of the discovery by the inventor of a phenomenon in which active atoms, (molecules) excited by irradiation with light can preserve their active energy, referred to hereafter as a first energy, for a relatively long time. The active energy of the atom partially remains after the atoms are laid on the substrate, the residual energy being referred to hereafter as the second energy. While undergoing a CVD method, atoms with the first energy are overlyinq the atoms with the second energy which are already deposited. According to experiment by the Applicant, the overlying atoms can wander on the substrate so that the sum of the first energy and the second energy takes less value. The wandering atoms can reach a bare surface of the substrate on which they are stabilized. This means that it is possible to form a layer even on a hidden surface from a principal surface. Further, the phenomenon makes it possible that a layer can be formed according to a new formation theorem which is entirely different from the exciting theorem. According to experiments described in detail infra, the phenomenon appears as if material is poured into a trench, like liquid. It is therefore an object of the invention to provide an improved CVD method capable of performing deposition on a depression region. It is another object of the invention to provide an improved CVD method according to which a thick layer is formed even on a depression region. It is further object of the invention to provide an improved CVD method according to which a deposition is established also in the inside of a deep cave. It is a still further object of the invention to produce an improved capacitor for a semiconductor memory. The above-discussed problem with respect to the uneven surface coated with an overlying layer is overcome. In accordance with the present invention, by isotropic etching of the uneven upper surface of the insulating film so that the upper surface on which overlying film is formed is made flat and smooth. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a CVD device used in methods of the invention. FIG. 2 is a section view of the semiconductor device formed in accordance with a first embodiment of the invention. FIGS. 3(A) to 3(c) are fragmentary section views showing a method for depositing a layer on a substrate in accordance with a second embodiment of the invention. FIGS. 4(A) to 4(c) are fragmentary section views showing a third embodiment of the invention. FIGS. 5(A) to 5(C) are fragmentary section views showing a fourth embodiment of the invention. FIG. 6 is a schematic view illustrating a reaction chamber usable in the present invention. FIGS. 7(A) to 7(D) are top elevational views of a substrate in which different caves are formed. FIGS. 8(A) to 8(E) are fragmentary sectional views showing a further embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an example of a CVD apparatus preferably used for the invention is shown. In the FIGURE, a CVD device comprises a reaction system 10, an exhausting system 11 and a reactant gas supply system 12. The reaction system 10 includes a prechamber 14 and a reaction chamber 13, both being evacuated in advance of deposition. First, a plurality of substrates 30 are prepared on which a deposition will be carried out. The substrates are supported on the holder 17 so as to be arranged apart from each other. Then, the plurality of substrates are transferred to the reaction chamber 13 from the prechamber 14 together with the holder 17 through a gate valve 31. In the reaction chamber 13, the substrates 30 are irradiated with ultraviolet light of 184 nm or 254 nm wavelength from a low pressure mercury lamp 21 in a light source chamber 22. The substrate 30 is irradiated with light from the lower side of the substrate 30 and heated from the upper side by a halogen lamp heater 16 provided in a heating chamber 15. Reactant gas is introduced to the reaction chamber 13 from a gas supply (not shown) via a flow rate meter 28, a valve 29 and a nozzle 18. In the reaction chamber 13, the gas constitutes flows designated with references 19 and 19' in which the gas is excited, made active and decomposed by the ultraviolet light emitted from the lamp 21, and a resultant product is deposited on the substrate 30 as a layer. As reactant gases, a mixed gas of polysilane and polyfluorosilane is used for the silicon layer. In addition to this reactant gas, an amount of ammonia gas can be further mixed to make a silicon nitride layer. When a p-type or an n-type semiconductor layer is desired, a suitable impurity or impurities may be blended. Such reactive gas is introduced with a carrier gas, if necessary. Further, the reactive gas for the silicon layer is mixed with oxide gas to form a silicon oxide layer, a phosphorous glass or a boron glass. Instead of a silicon layer, an alkylmetal can be introduced to form a metal layer, or an alkylmetal and a polysilane can be introduced to form a layer composed of a metal and a silicide. Referring now to FIG. 2, a section view of an experimental product formed by the above method is described to show a first embodiment of the invention. This product was fabricated using a monocrystalline silicon substrate 30' of 15 mm long×20 mm wide×380 micron meters thick. The substrate 30' was irradiated with ultraviolet light at 3 torr. Then, as shown in the FIGURE, a silicon nitride layer 33 was formed on the substrate 30' with a thickness of 1000 A on the bottom and also with a thickness of 1000 A on the side wall. The noticeable result of the experiment is that the silicon nitride layer 33" as observed also on the upper surface as an extension 35 of 5 mm, whose thickness was measured of 1000 A on the edge portion having 2 mm width from the side wall of the substrate 30'. What is further of interest is that the wandering of the deposited materials seems to depend little on the temperature of the substrate 30'. A silicon nitride layer can be formed at a temperature less than 400° C. Needless to say, no layer is formed without irradiation even at about 300° C.. FIGS. 3(A) to 3(c) are fragmentary cross sectional views showing a second embodiment according to the invention. On a silicon semiconductor substrate 1 is a silicon nitride layer 2 which was etched to prepare an opening as a mask for a trench 3. The trench 3 as created by etching with the nitride layer 2 as a mask. After removing the silicon nitride layer 2, a silicon oxide layer as deposited on the substrate 1 in accordance with the method explained above in conjunction with FIG. 1. In FIG. 3(B), broken lines 4 are plotted to explain how the silicon nitride layer 36 was grown. The broken lines 4-1 to 4-4 show contours in sequence of the layer growing. The thickness of each layer deposited on each step 35-1 and 35-1', 35-2 and 35-2' . . . , or 35-4 was observed to be uniform throughout the deposited surface including the inside of the trench 3. Since the uppermost surface of the layer 3 just over the trench tends to be finished in the form of a concave, the upper portion of the layer may be removed by isotropic etching to level the surface as shown in FIG. 3(C). Although this experiment was carried out to form a silicon oxide layer, other layers of silicide such as a silicon nitride layer can be formed according to a similar process, such as silicon nitride. Also, after completion of a layer different from a silicon oxide layer, the surface of the layer may be oxidized to form a surface of silicon oxide. Contrary to existing technique, the CVD according to the invention is carried out at relatively low temperature (about 300° C.) since the bottom of a trench is likely to produce lattice defects therein at a high temperature. The layer thus formed, however, has a very fine structure comparable with a layer conventionally formed at higher than 1000° C. Referring to FIGS. 4(A) to 4(c), a third embodiment is shown. The embodiment includes an extrinsic semiconductor. The process is substantially identical to the preceding embodiment so that redundant descriptions will not be repeated. On a silicon semiconductor are a silicon oxide or a silicon nitride layer 4, a polysilioon or amorphous silicon layer 5 which is doped with phosphorus as which is an impurity or a metallic conductive layer 5 such as of titanium chloride or tungsten, and a silicon oxide layer 6. In this configuration, a capacitance is constituted between the semiconductor substrate 1 and the conductive layer 6. A fourth embodiment of the invention is shown in FIGS. 5(a) to 5(C). The experiment was made to form a semiconductor device in which a cave is formed in a trench to increase the capacitance formed in the trench. The trench was formed with the depth of 5 micron meters and with the width of 2.5 micron meters at the upper portion and of 1.5 micron meters at the bottom portion, with a silicon nitride layer 2 and a silicon oxide 2' as a mask as shown in FIG. 5(A). Thereafter a silicon nitride layer 45 and 45, was deposited by a CVD method using light irradiation. Then the silicon nitride layer was let undergo an anisotropic etching to remove selectively the upper layer 45' and the part of the layer 45 formed on the bottom portion 39 of the trench 3. Further, for the substrate 1, an anisotropic etching was carried out to perform a lateral etching so that a cave 40 is formed. After removing the silicon oxide layer 2' and the silicon nitride layer 2, a silicon oxide layer 41 was deposited on the inside walls of the cave 40, the trench 3 and the surface of the semiconductor substrate 1 according to the method which is the same as that discussed in the preceding. Further on the layer 41 is formed a titanium silicide layer or silicon layer 42 which is doped with phosphorus, an insulating layer 4 such as silicon oxide or silicon nitride and a conductive layer 5 such as a polycrystalline silicon or titanium silicide layer which is doped with phosphorus, each layer being fabricated by a CVD method according to the present invention. Thereafter, a silicon oxide layer 46 was superimposed on the laminate over the trench 3 so as to completely stop the trench. During the process, contacts 44 and 43 ere defined by photolithography. Consequently, an improved semiconductor device was obtained with large capacitance. The etching process illustrated in FIGS. 5(A) and 5(B) will be explained with reference to FIG. 6, inside a reaction chamber, a substrate to be etched is disposed between a pair of electrodes. As an etchant gas, CF 4 , CF 3 Br, CCl 4 i or the like is inputted to the reaction chamber at a negative pressure. An alternating voltage, biased if necessary, is applied to the pair of electrodes to initiate discharge in between, whereupon a chemical vapor reaction takes place. Then, the chemical vapor reaction generates a plasma gas in the reaction chamber by virtue of the energy of the discharge. Under the alternating electric field induced by the applied voltage, the plasma particles reciprocate (resonate) in vertical particles reciprocate (resonate) in a vertical direction between the electrodes, and collide with the horizontal surface of the substrate perpendicularly to the direction of the electric field in the vicinity of the substrate. This etching process is called RIE (Reaction Ion Etching). The film 2 somewhat hides the side wall of the case 3. The reason why the side wall is partially removed adjacent to the bottom of the case 3 is that the side wall is slightly inclined and therefore not perfectly free from etching, that the anisotropy of RIE is not perfect, and that the effect of the hiding by the film 2 is lessened as departing from the film 2. The direction of anisotropy etching depends on the crystal orientation, having planes designated conventionally as (110) and (111), and the etchant. Some etchant attacks on the (111) planes at a low rate as compared with the other planes, while another etchant attacks on the plane (110) at a high rate as compared with the other planes. Speaking about FIG. 5(C). the cave is desirably formed, in order to increase the inner surface area, like the low portion of a wine-glass as illustrated in FIGS. 7(A) and 7(B). Of course, the lower profile of the cave may be elongated only in one horizontal direction as shown in the sketches 7(C) and 7(D), by appropriately choosing the orientation of the crystal and the etchant. Anisotropic etching itself is well-known in the art. Referring to FIGS. 8(A) to 8(E), a method for making interconnections between an electrode pattern of a lower level and another electrode pattern of a higher level is described. A silicon semiconductor substrate 51 is covered with an upper silicon oxide film 53 formed by CVD, for example, as illustrated in FIG. 8(A). Semiconductor devices may be fabricated within the substrate such as FET's or Bi-CMOS's. An aluminum film is formed to a thickness of 2 microns, for example, and patterned by known photolithographic techniques to produce a first electrode pattern 55 on the silicon oxide film 53 (FIG. 8(B)). The spacing between the constituent electrode strips of the pattern 55 can be as narrow as 1 micron. An insulating film of silicon nitride is deposited over the pattern in the same manner as the foregoing embodiments, completely filling the intervals between the strips of the pattern. The thickness of the insulating film 57 is typically about 2 microns. The depressions (between electrode strips 55 in this embodiment) can be sufficiently filled with silicon nitride, for example, even when the width of the depressions is less than the depth thereof. In accordance with the present invention, the upper surface 59 of the insulating film 57 is made flat by isotropic etching with an etchant of NF 3 , for example. With a suitable mask, through-holes 61 are opened in silicon nitride film 57 by etcing. A second electrode pattern 63 is formed from an aluminum film on flat surface 59 of silicon nitride film 57 in the same manner as the first electrode pattern, while king contact with the first electrode through the openings 61. Due to the isotropic etch, contact between the first and second electrode patterns is effected. While the present invention has been described with reference to several preferred embodiments thereof, many variations and modifications will now occur to those skilled in the art. The scope of the present application is limited solely by the scope of the appended claims and not by the specific embodiments disclosed herein.
An improved capacitor for a semiconductor memory, and method for depositing material on a substrate is shown. The material to be deposited is energized by irradiation with light in a chamber in which a CVD method is carried out. The energy induced by the irradiation remains in the molecules of the material even after the molecules have lain on the substrate. With the residual energy, the molecules can wander on the substrate even to a hidden surface. Due to this wandering, the deposition can be performed also on the inside of a deep cave.
Summarize the patent document, focusing on the invention's functionality and advantages.
[ "REFERENCE TO RELATED APPLICATION This is a divisional application of Ser.", "No. 07/311,402, filed Feb. 15, 1989 (now abandoned), which is a CIP application of Ser.", "No. 07/137,567, filed Dec. 24, 1987 (now abandoned) which is a CIP of Ser.", "No. 06/909,203, now U.S. Pat. No. 4,735,821.", "BACKGROUND OF THE INVENTION This invention relates to a capacitor for a semiconductor memory, and to a method in which a photo CVD process is carried out so that the deposition is effectively performed also on insides of depressions.", "There is broadly known and used a low pressure CVD method, a plasma CVD method, and a chemical vapor deposition method for semiconductor processing.", "In the semiconductor processing method, depressions such as a hole, a trench, a cave (a sub-surface re-entrant opening having surfaces out of line-of-sight) or so on are configured on whose surfaces are placed a product created by the CVD method to form a buried field insulating layer or an electric element such as a capacitance in the depression, or to fill an over-etching region in the form of a depression.", "When a formation of a layer on the depression is desired, it is inevitable that the thickness "ds"", "of the layer on an inner surface (depression) and the thickness "dt"", "of the layer on an upper surface result in dt/ds>1.", "One of the problems of researching to obtain a finely configured semiconductor in the VLSI field is how an inverse ratio, namely ds/dt, can be increased near 1.", "Further, in the case where the depth of a cave has a measure more than the measure of the opening of the cave, it was impossible to form a uniform layer throughout the inside of the cave.", "Such caves are formed, e.g., with a known trench method which can dig a cave of depth having a measure 3 to 5 times as large as the measure of the width of the opening thereof.", "Anyhow, existing methods are not suitable to perform a deposition in such a cave.", "Namely, according to an existing CVD method, atoms or molecules are deposited on a substrate in an excited condition which are diffused into vapor after being decomposed or after undergoing a reaction caused by thermal energy.", "The existing process can be performed effectively when it is carried out under negative pressure, since the active molecules have a relatively long mean free path in the vapor under a negative pressure, compared with that under the atmospheric pressure.", "For example, on a substrate with a trench of 2 micron meters in width and also in depth, a depression resulted in a layer 1 of micron meter thickness on the upper surface, a layer with at most a thickness of 0.7 micron meter on the side wall of the trench and a layer with the thickness of 0.6 micron meter on the bottom of the trench.", "In any case, a step coverage ds/dt is expected only up to about 0.7.", "According to another known method, step coverages are no more than that of the above method.", "Normally, ds/dt=0.3-0.5.", "A plasma enhanced CVD alone is comparable with the above LPCVD.", "Another problem associated with the prior art is as follows.", "When a surface having depressions is coated with an overlying layer, the top surface of the overlying layer inevitably becomes uneven.", "Some troubles are caused by the uneven surface.", "For example, when a multi-level interconnection is produced with intervening insulating films for isolating constituent electrode arrangements on different levels (as illustrated in FIGS. 8(A)-8(E)), the electrode arrangement (or pattern) overlying an uneven surface of the intervening insulating film may not be connected to the electrode pattern beneath the intervening insulating film.", "SUMMARY OF THE INVENTION This application is directed to a capacitor which can be used for finely densed capacitances formed on a semiconductor memory, and to a method for coating the side surface of a trench other than its bottom.", "The opening of the coating on the bottom can be used for forming a capacitance, a transistor, or so forth.", "The invention has been conceived on the basis of the discovery by the inventor of a phenomenon in which active atoms, (molecules) excited by irradiation with light can preserve their active energy, referred to hereafter as a first energy, for a relatively long time.", "The active energy of the atom partially remains after the atoms are laid on the substrate, the residual energy being referred to hereafter as the second energy.", "While undergoing a CVD method, atoms with the first energy are overlyinq the atoms with the second energy which are already deposited.", "According to experiment by the Applicant, the overlying atoms can wander on the substrate so that the sum of the first energy and the second energy takes less value.", "The wandering atoms can reach a bare surface of the substrate on which they are stabilized.", "This means that it is possible to form a layer even on a hidden surface from a principal surface.", "Further, the phenomenon makes it possible that a layer can be formed according to a new formation theorem which is entirely different from the exciting theorem.", "According to experiments described in detail infra, the phenomenon appears as if material is poured into a trench, like liquid.", "It is therefore an object of the invention to provide an improved CVD method capable of performing deposition on a depression region.", "It is another object of the invention to provide an improved CVD method according to which a thick layer is formed even on a depression region.", "It is further object of the invention to provide an improved CVD method according to which a deposition is established also in the inside of a deep cave.", "It is a still further object of the invention to produce an improved capacitor for a semiconductor memory.", "The above-discussed problem with respect to the uneven surface coated with an overlying layer is overcome.", "In accordance with the present invention, by isotropic etching of the uneven upper surface of the insulating film so that the upper surface on which overlying film is formed is made flat and smooth.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a CVD device used in methods of the invention.", "FIG. 2 is a section view of the semiconductor device formed in accordance with a first embodiment of the invention.", "FIGS. 3(A) to 3(c) are fragmentary section views showing a method for depositing a layer on a substrate in accordance with a second embodiment of the invention.", "FIGS. 4(A) to 4(c) are fragmentary section views showing a third embodiment of the invention.", "FIGS. 5(A) to 5(C) are fragmentary section views showing a fourth embodiment of the invention.", "FIG. 6 is a schematic view illustrating a reaction chamber usable in the present invention.", "FIGS. 7(A) to 7(D) are top elevational views of a substrate in which different caves are formed.", "FIGS. 8(A) to 8(E) are fragmentary sectional views showing a further embodiment of the invention.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an example of a CVD apparatus preferably used for the invention is shown.", "In the FIGURE, a CVD device comprises a reaction system 10, an exhausting system 11 and a reactant gas supply system 12.", "The reaction system 10 includes a prechamber 14 and a reaction chamber 13, both being evacuated in advance of deposition.", "First, a plurality of substrates 30 are prepared on which a deposition will be carried out.", "The substrates are supported on the holder 17 so as to be arranged apart from each other.", "Then, the plurality of substrates are transferred to the reaction chamber 13 from the prechamber 14 together with the holder 17 through a gate valve 31.", "In the reaction chamber 13, the substrates 30 are irradiated with ultraviolet light of 184 nm or 254 nm wavelength from a low pressure mercury lamp 21 in a light source chamber 22.", "The substrate 30 is irradiated with light from the lower side of the substrate 30 and heated from the upper side by a halogen lamp heater 16 provided in a heating chamber 15.", "Reactant gas is introduced to the reaction chamber 13 from a gas supply (not shown) via a flow rate meter 28, a valve 29 and a nozzle 18.", "In the reaction chamber 13, the gas constitutes flows designated with references 19 and 19'", "in which the gas is excited, made active and decomposed by the ultraviolet light emitted from the lamp 21, and a resultant product is deposited on the substrate 30 as a layer.", "As reactant gases, a mixed gas of polysilane and polyfluorosilane is used for the silicon layer.", "In addition to this reactant gas, an amount of ammonia gas can be further mixed to make a silicon nitride layer.", "When a p-type or an n-type semiconductor layer is desired, a suitable impurity or impurities may be blended.", "Such reactive gas is introduced with a carrier gas, if necessary.", "Further, the reactive gas for the silicon layer is mixed with oxide gas to form a silicon oxide layer, a phosphorous glass or a boron glass.", "Instead of a silicon layer, an alkylmetal can be introduced to form a metal layer, or an alkylmetal and a polysilane can be introduced to form a layer composed of a metal and a silicide.", "Referring now to FIG. 2, a section view of an experimental product formed by the above method is described to show a first embodiment of the invention.", "This product was fabricated using a monocrystalline silicon substrate 30'", "of 15 mm long×20 mm wide×380 micron meters thick.", "The substrate 30'", "was irradiated with ultraviolet light at 3 torr.", "Then, as shown in the FIGURE, a silicon nitride layer 33 was formed on the substrate 30'", "with a thickness of 1000 A on the bottom and also with a thickness of 1000 A on the side wall.", "The noticeable result of the experiment is that the silicon nitride layer 33"", "as observed also on the upper surface as an extension 35 of 5 mm, whose thickness was measured of 1000 A on the edge portion having 2 mm width from the side wall of the substrate 30'.", "What is further of interest is that the wandering of the deposited materials seems to depend little on the temperature of the substrate 30'.", "A silicon nitride layer can be formed at a temperature less than 400° C. Needless to say, no layer is formed without irradiation even at about 300° C..", "FIGS. 3(A) to 3(c) are fragmentary cross sectional views showing a second embodiment according to the invention.", "On a silicon semiconductor substrate 1 is a silicon nitride layer 2 which was etched to prepare an opening as a mask for a trench 3.", "The trench 3 as created by etching with the nitride layer 2 as a mask.", "After removing the silicon nitride layer 2, a silicon oxide layer as deposited on the substrate 1 in accordance with the method explained above in conjunction with FIG. 1. In FIG. 3(B), broken lines 4 are plotted to explain how the silicon nitride layer 36 was grown.", "The broken lines 4-1 to 4-4 show contours in sequence of the layer growing.", "The thickness of each layer deposited on each step 35-1 and 35-1', 35-2 and 35-2'", ", or 35-4 was observed to be uniform throughout the deposited surface including the inside of the trench 3.", "Since the uppermost surface of the layer 3 just over the trench tends to be finished in the form of a concave, the upper portion of the layer may be removed by isotropic etching to level the surface as shown in FIG. 3(C).", "Although this experiment was carried out to form a silicon oxide layer, other layers of silicide such as a silicon nitride layer can be formed according to a similar process, such as silicon nitride.", "Also, after completion of a layer different from a silicon oxide layer, the surface of the layer may be oxidized to form a surface of silicon oxide.", "Contrary to existing technique, the CVD according to the invention is carried out at relatively low temperature (about 300° C.) since the bottom of a trench is likely to produce lattice defects therein at a high temperature.", "The layer thus formed, however, has a very fine structure comparable with a layer conventionally formed at higher than 1000° C. Referring to FIGS. 4(A) to 4(c), a third embodiment is shown.", "The embodiment includes an extrinsic semiconductor.", "The process is substantially identical to the preceding embodiment so that redundant descriptions will not be repeated.", "On a silicon semiconductor are a silicon oxide or a silicon nitride layer 4, a polysilioon or amorphous silicon layer 5 which is doped with phosphorus as which is an impurity or a metallic conductive layer 5 such as of titanium chloride or tungsten, and a silicon oxide layer 6.", "In this configuration, a capacitance is constituted between the semiconductor substrate 1 and the conductive layer 6.", "A fourth embodiment of the invention is shown in FIGS. 5(a) to 5(C).", "The experiment was made to form a semiconductor device in which a cave is formed in a trench to increase the capacitance formed in the trench.", "The trench was formed with the depth of 5 micron meters and with the width of 2.5 micron meters at the upper portion and of 1.5 micron meters at the bottom portion, with a silicon nitride layer 2 and a silicon oxide 2'", "as a mask as shown in FIG. 5(A).", "Thereafter a silicon nitride layer 45 and 45, was deposited by a CVD method using light irradiation.", "Then the silicon nitride layer was let undergo an anisotropic etching to remove selectively the upper layer 45'", "and the part of the layer 45 formed on the bottom portion 39 of the trench 3.", "Further, for the substrate 1, an anisotropic etching was carried out to perform a lateral etching so that a cave 40 is formed.", "After removing the silicon oxide layer 2'", "and the silicon nitride layer 2, a silicon oxide layer 41 was deposited on the inside walls of the cave 40, the trench 3 and the surface of the semiconductor substrate 1 according to the method which is the same as that discussed in the preceding.", "Further on the layer 41 is formed a titanium silicide layer or silicon layer 42 which is doped with phosphorus, an insulating layer 4 such as silicon oxide or silicon nitride and a conductive layer 5 such as a polycrystalline silicon or titanium silicide layer which is doped with phosphorus, each layer being fabricated by a CVD method according to the present invention.", "Thereafter, a silicon oxide layer 46 was superimposed on the laminate over the trench 3 so as to completely stop the trench.", "During the process, contacts 44 and 43 ere defined by photolithography.", "Consequently, an improved semiconductor device was obtained with large capacitance.", "The etching process illustrated in FIGS. 5(A) and 5(B) will be explained with reference to FIG. 6, inside a reaction chamber, a substrate to be etched is disposed between a pair of electrodes.", "As an etchant gas, CF 4 , CF 3 Br, CCl 4 i or the like is inputted to the reaction chamber at a negative pressure.", "An alternating voltage, biased if necessary, is applied to the pair of electrodes to initiate discharge in between, whereupon a chemical vapor reaction takes place.", "Then, the chemical vapor reaction generates a plasma gas in the reaction chamber by virtue of the energy of the discharge.", "Under the alternating electric field induced by the applied voltage, the plasma particles reciprocate (resonate) in vertical particles reciprocate (resonate) in a vertical direction between the electrodes, and collide with the horizontal surface of the substrate perpendicularly to the direction of the electric field in the vicinity of the substrate.", "This etching process is called RIE (Reaction Ion Etching).", "The film 2 somewhat hides the side wall of the case 3.", "The reason why the side wall is partially removed adjacent to the bottom of the case 3 is that the side wall is slightly inclined and therefore not perfectly free from etching, that the anisotropy of RIE is not perfect, and that the effect of the hiding by the film 2 is lessened as departing from the film 2.", "The direction of anisotropy etching depends on the crystal orientation, having planes designated conventionally as (110) and (111), and the etchant.", "Some etchant attacks on the (111) planes at a low rate as compared with the other planes, while another etchant attacks on the plane (110) at a high rate as compared with the other planes.", "Speaking about FIG. 5(C).", "the cave is desirably formed, in order to increase the inner surface area, like the low portion of a wine-glass as illustrated in FIGS. 7(A) and 7(B).", "Of course, the lower profile of the cave may be elongated only in one horizontal direction as shown in the sketches 7(C) and 7(D), by appropriately choosing the orientation of the crystal and the etchant.", "Anisotropic etching itself is well-known in the art.", "Referring to FIGS. 8(A) to 8(E), a method for making interconnections between an electrode pattern of a lower level and another electrode pattern of a higher level is described.", "A silicon semiconductor substrate 51 is covered with an upper silicon oxide film 53 formed by CVD, for example, as illustrated in FIG. 8(A).", "Semiconductor devices may be fabricated within the substrate such as FET's or Bi-CMOS's.", "An aluminum film is formed to a thickness of 2 microns, for example, and patterned by known photolithographic techniques to produce a first electrode pattern 55 on the silicon oxide film 53 (FIG.", "8(B)).", "The spacing between the constituent electrode strips of the pattern 55 can be as narrow as 1 micron.", "An insulating film of silicon nitride is deposited over the pattern in the same manner as the foregoing embodiments, completely filling the intervals between the strips of the pattern.", "The thickness of the insulating film 57 is typically about 2 microns.", "The depressions (between electrode strips 55 in this embodiment) can be sufficiently filled with silicon nitride, for example, even when the width of the depressions is less than the depth thereof.", "In accordance with the present invention, the upper surface 59 of the insulating film 57 is made flat by isotropic etching with an etchant of NF 3 , for example.", "With a suitable mask, through-holes 61 are opened in silicon nitride film 57 by etcing.", "A second electrode pattern 63 is formed from an aluminum film on flat surface 59 of silicon nitride film 57 in the same manner as the first electrode pattern, while king contact with the first electrode through the openings 61.", "Due to the isotropic etch, contact between the first and second electrode patterns is effected.", "While the present invention has been described with reference to several preferred embodiments thereof, many variations and modifications will now occur to those skilled in the art.", "The scope of the present application is limited solely by the scope of the appended claims and not by the specific embodiments disclosed herein." ]
This application is a continuation of application Ser. No. 297,490, filed Jan. 17,1989 now abandoned. FIELD OF THE INVENTION This invention pertains to a window lock and, more particularly, to a window lock which provides for multi-point sequential locking of a window sash to a window frame. Additionally, the window lock provides for improved locking at each of the locking points. BACKGROUND OF THE INVENTION Movable windows in general use have sash which are either sliding, double hung or pivotal, with the latter type including awning and casement windows. Many different forms of window locks are available for locking a movable window. The assignee of the invention disclosed herein markets window locks for such movable windows. In many instances, the window can be of such size or of a structural material which renders it desirable to have multi-point locking. It is known to mount individual window locks at spaced points or locations on the window to achieve multi-point locking. Typically, each of the window locks is independently operable. However, the movable mechanisms of a pair of window locks can be connected together for simultaneous movement from a single handle as shown in the Van Klompenburg U.S. Pat. No. 4,095,829, owned by the assignee of this invention. Multi-point locking is shown in the Van Benschoten U.S. Pat. No. 2,114,645. There are commercially-available multi-point window lock structures operable by a single handle. The foregoing prior art does not disclose structure providing for sequential locking of the multi-point locking structure to provide for a delayed lock-up to accommodate racked or warped windows, nor do such structures have a window lock constructed to counteract flexibility of the window structure as may be encountered with a vinyl window. SUMMARY OF THE INVENTION A primary feature of the invention is to provide a window lock having improved locking functions for locking a window sash to a window frame and, more particularly, to a window lock constructed to provide for multi-point locking to lock a window sash to a window frame at spaced locations, with delayed lock-up of one lock structure relative to the other to accommodate racked or warped windows and with the structure also taking into account other considerations which may arise in locking of a window having some flexure, such as a vinyl window. Additional features of the invention relate to the versatility of the window lock in providing for simple, selective assembly of components to achieve the desired number of locking points; the assurance that the window lock mechanism cannot move by any force applied thereto other than by an operating handle; the sealing of a window lock housing to the window frame to render the window lock light, water and airtight; and an arrangement of the operating mechanism operable by the handle whereby the handle can have two limit positions wherein, in one limit position, the handle establishes a locked condition of the window with the handle close to the window frame and, in going to the other limit position, wherein the window is unlocked, the handle has moved through an arc approaching 180° wherein there is limited protrusion of the handle outwardly of the housing when the window is unlocked. An object of the invention is to provide a new and improved window lock. Another object of the invention is to provide a new and improved multi-point window lock and, more particularly, such a window lock for vinyl windows. A further object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window; the improvement comprising: multi-point locking of the window sash to the window frame by utilization of at least two of said ramped keepers and two of said cam members, each of said ramped keepers having an inclined ramp section and a generally planar section, and said slider having a length of movement along said path greater than that required to move a cam member along said ramp section and onto a generally planar section of a ramped keeper whereby delayed lock-up of one cam member and associated ramped keeper may be achieved relative to the other cam member and ramped keeper by having said ramped keepers at a distance apart greater than the distance between said cam members and a planar section of a ramped keeper having a length greater than said difference in distances. Still another object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window; the improvement comprising: a housing; a handle rotatably mounted on said housing for movement between two limit positions and operable to move said slider along said path and said slider and handle having coacting means to preclude gravity or other outside force from moving said slider along said path without moving said handle. An additional object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window; the improvement comprising: each of said cam member and ramped keeper being bevelled to resist any separating movement in a direction normal to said path as a result of flexibility of the window frame and window sash as may result due to high loads. DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, perspective view of a window shown in open position and which has the window lock structure of FIGS. 2-7 associated therewith; FIG. 2 is a side elevation of the window lock hardware shown without association with the window sash and window frame and with the window lock in unlocked position and being a view generally similar to that of FIG. 3 and with parts broken away; FIG. 3 is a view similar to FIG. 2 showing the window lock hardware in window-locking position and with the view being taken generally along the line 3--3 in FIG. 4; FIG. 4 is a sectional view taken generally along the line 4--4 in FIG. 10; and showing the structure in association with the window frame and window sash; FIG. 5 is a view similar to FIG. 4 and taken generally along the line 5--5 in FIG. 10; FIG. 6 is a fragmentary diagrammatic view of a part of the structure as positioned as shown in FIG. 2 and illustrating a first toggle position; FIG. 7 is a view similar to FIG. 6 and illustrating a second toggle position for the structure in window lock position and as shown in FIG. 3; FIG. 8 is a fragmentary elevation of the housing; FIG. 9 is an elevation view of the handle; and FIG. 10 is a fragmentary, perspective view of a window shown in the closed position having the window lock structure of FIGS. 2-7 associated therewith. DESCRIPTION OF THE PREFERRED EMBODIMENT The window lock is shown in association with a window in FIG. 1 and with the only room-visible part thereof being a housing 10 and a handle 12. The window has a window frame, indicated generally at 14, in which the window sash, generally indicated at 16, of a casement window is pivotally mounted. The mounting of such a window by hinges is well known in the art as well as use of a window operator, indicated generally at 18, for moving the window sash between closed and fully open positions or any desired position therebetween. As will be readily recognized, the window lock can also be used for an awning-type window wherein the pivotal movement of the window sash would be generally about a horizontal axis, rather than the vertical axis of the casement window. The concepts embodied in the window lock could be utilized with other types of movable windows, such as a double hung window. The window lock has particular utility with a vinyl window and an embodiment of a vinyl window is shown fragmentarily in FIGS. 4 and 5. The window frame 14 has vertical wall sections 20 and 22 suitably integrally interconnected by interconnecting walls and with a pair of interconnected vertical walls 24 and 26 extending at right angles thereto and with the wall 26 defining a room-facing surface of the window frame. The window sash 16 has a vertical exterior wall 28 with integrally associated walls including a wall 30 extending normal thereto which defines one of the walls mounting a vertical face panel 32 which can be brought closely adjacent to the vertical frame wall 24 when the window is closed and with a suitable weather strip 34 assuring a tight seal. The window lock has a slider 40 movable in a path extending lengthwise thereof and which mounts a cam member, in the form of a roller 42. The slider 40 is movable in said path by its mounting on a planar part of a bracket 44 which mounts a pair of shouldered guide rivets 46 and 48 which extend through the respective slider slots 50 and 52, respectively, and which enable movement of the slider from the window unlocked position, shown in FIG. 2, to the window locked position, shown in FIG. 3. The bracket 44 has a pair of bracket flanges 54 and 56 at right angles to the planar part thereof which can receive a pair of fasteners 58 and 60, respectively, which thread into a pair of alignment bosses 62 and 64 extending inwardly from the housing 10 and which fit into a slot formed in the walls 24 and 26 of the window frame. The inner face of the housing 10 extends beyond the perimeter of the opening in the window frame to abut against the interior room face of the vertical frame wall 26. The fasteners 58 and 60 can draw the bracket flanges 54 and 56 against the inner face of the frame wall 24 and the perimeter of the housing 10 against the wall 26 to capture the window frame therebetween. The perimeter part of the housing which bears against the wall 26 includes a continuous O-ring groove, parts of which are shown at 66 and 68 and which receive an O-ring to effect a light, water and airtight seal between the housing and the window frame. The housing 10 rotatably mounts the handle 12 for movement between two limit positions. One of these limit positions is the window locked position, as shown in FIG. 3, wherein the handle 12 extends doWnwardly and generally parallel to the frame wall 26. The handle can move to its other limit position, as seen in FIG. 2, which is the window unlocked position. This movement of the handle is through an arc approaching 180° whereby the handle, as seen in FIG. 2, barely extends beyond the housing 10 and, thus, does not protrude into the room when the window is open. The slider 40 and handle 12 have coacting means whereby rotation of the handle results in linear movement of the slider along the path lengthwise of the slider. This coacting means comprises a drive link 70 splined to the handle at its rotation axis and which has a pin 72 which coacts with a forked section of the slider. This forked section has a pair of tines 74 and 76 with an open-ended slot therebetween. With the window lock in locked condition and with the handle 12 in the position shown in FIG. 3, the handle can be rotated in a counterclockwise direction to the position shown in FIG. 2 and, during this rotation, the pin 72 will move sequentially inwardly and outwardly of the slot and in engagement with the tine 76 to move the slider 40 downwardly, as viewed in FIGS. 2 and 3. In return of the handle 12 to the position of FIG. 3, the handle 12 is rotated clockwise and the pin 72 moves sequentially inwardly and outwardly of the slot and coacts with an edge of the tine 74 to raise the slider, as viewed in FIGS. 2 and 3. The planar part of the bracket 44 has an arcuate cut-out 80 to permit the free end of the drive link 70 to move between the positions shown in FIGS. 2 and 3. The ends of the tines 74 and 76 of the forked section of the slider are bevelled to enable movement of the drive link 70 to a toggle position in either of the limit positions of the handle. This is diagrammatically illustrated in FIGS. 6 and 7. With the handle 12 moving to the window unlocked position of FIG. 2, the drive pin 72 moves in a counterclockwise direction, as viewed in FIG. 6, and the downward arc to a toggle position is permitted by the bevelled end 82 of the tine 76. The pin 72 has reached a toggle position wherein, if an upward force is exerted on the slider 40 as indicated by the upwardly-directed arrow, the bevelled end 82 of the tine 76 engages the pin 72 and tends to move the pin toward the right. This movement is prevented by coaction between the housing and the handle. This coaction is achieved by structure shown in FIGS. 8 and 9. FIG. 8 shows a side wall 83 of the housing 10 having an opening 84 to receive a stem 85 (FIG. 9) of the handle 12. A pair of abutments 86a and 86b are formed on the housing to define rotatable limit positions for the handle 12 by coaction with an arcuate rib 87 on the handle. The rib 87 has an included arc of approximately 104°, although not intended to be limiting, and the abutments 86a and 86b are spaced apart through an angular distance of approximately 250° whereby the handle can rotate through an arc of approximately 150°. A similar toggle position is achieved when the handle 12 is in window locked position. As seen in FIG. 7, any downward force applied on the slider 40, as represented by the downwardly-directed arrow, would cause a bevelled end 88 of the tine 74 to engage the drive pin 72 and urge the drive link 70 in a clockwise direction, as indicated by the arrow, which would be prevented by coaction of the handle 12 with the housing 10. The slider 40 cannot be moved by any outside force other than by handle movement. The previously-mentioned cam member on the slider 40, which is the roller 42, coacts with a ramped keeper 100 which is mounted by suitable means to the vertical wall 30 of the window sash. The ramped keeper has an inclined ramp section 102 and a generally planar section 104. The ramped keeper 100 is shown in FIG. 2 in relation to the roller 42 when the window sash is not fully closed. With clockwise rotation of the handle 12 toward the locked position shown in FIG. 3, the slider 40 moves upwardly and the roller 42 engages the inclined ramp section 102 and rolls therealong to draw and maintain the window sash fully closed when the roller 42 moves onto the generally planar section 100 of the ramped keeper. The ramped keeper can be a solid member, as shown, or can be shaped from a metal plate. In order to achieve multi-point locking, the window sash mounts a second ramped keeper 110 having the same construction as the ramped keeper 100 and at a distance therefrom A second cam member, in the form of a roller 112, coacts with the ramped keeper 110. This roller 112 is rotatably-mounted on a tie bar 114 which is connected to an end of the slider 40 for lengthwise movement therewith. An upper end of the tie bar is movable within a tie bar guide 116 which is fastened to the frame wall 20 by fasteners 118. Versatility in the location of points of locking is achieved by the manner in which a tie bar 114 may be associated with the slider 40. The tie bar 114 has a slot 120 at the lower end thereof which extends lengthwise of the tie bar. A tie bar rivet 122 is fixed to an offset upper end of the slider 40 and has a pair of aligned ears at a distance from the slider. With the tie bar 114 at an angle to the slider, the slot 120 can be aligned with the aligned ears of the tie bar rivet and the tie bar then moved past the ears and, thereafter, rotated to an alignment position, with the aligned ears then locking the tie bar 114 to the slider. There is also a tie bar rivet 124 at the lower end of the slider. The tie bar 114 can thus extend downwardly from the slider 40. Two tie bars can be used. Further variations can be achieved by the use of additional rollers with each tie bar (and additional ramped keepers) and the use of varying length tie bars. The multi-point locking is achieved with delayed lock-up of the roller 112 and ramp keeper 110 relative to the roller 42 and ramped keeper 100 by the slider having a length of movement along its path greater than that required to move a roller along the inclined ramp section 102 and onto a generally planar section 104 of a ramped keeper and having the ramped keepers at a distance apart greater than the distance between the rollers. A generally planar section of a ramped keeper has a length greater than the differences in the distances to provide a dwell for one roller while the other roller is on an inclined ramp section. An added feature with particular utility for a vinyl window because of the flexibility thereof is the bevelling of the rollers 42 and 112 and the generally planar sections 104 of the ramped keepers, as seen in FIGS. 4 and 5, to resist separation therebetween in a direction normal to the path of the slider 40. Referring more particularly to FIG. 4, any tendency of the window sash to move toward the left, which would cause separation between the ramped keeper and the roller, is resisted by the bevelled relation therebetween. The sequential locking action at the multiple lock points has a further advantage in limiting the maximum amount of force required at any one time to achieve the full locking of the window. From the foregoing, it will be evident that a window lock with extreme versatility and providing for multi-point locking has been provided. With the structure of the ramped keepers having the elongate generally planar sections providing an elongate dwell, there is an enhanced versatility in that the ramped keepers can be located in a desired relation to achieve the desired sequence of locking at various locking points. The tie bars can be provided in different lengths and with different numbers of rollers thereon and the desired tie bars can readily be associated with the slider at either the top or bottom thereof with the simple rotation connection which does not require the use of any attaching screws between the tie bar and the slider.
A window lock having plural ramped keepers for a window sash and plural rollers movably associated with a slider mountable on a window frame to provide multi-point locking. The ramped keepers are constructed and related to enable delayed lock-up of one roller and ramped keeper relative to the other in order to assure locking of racked or warped windows. A roller and associated ramped keeper are bevelled to counteract any flexibility that might be encountered in a flexible window, such as a window made of vinyl. The actuating mechanism provides for toggle positioning of the rotatable actuating handle and associated drive link to prevent movement of the lock mechanism by outside forces other than the handle. One or more tie bars, each having a roller, can be associated with the slider to provide for variation in the number of locking points and with further variations being achieved by the length of the tie bars as well as the number of rollers mounted thereon.
Condense the core contents of the given document.
[ "This application is a continuation of application Ser.", "No. 297,490, filed Jan. 17,1989 now abandoned.", "FIELD OF THE INVENTION This invention pertains to a window lock and, more particularly, to a window lock which provides for multi-point sequential locking of a window sash to a window frame.", "Additionally, the window lock provides for improved locking at each of the locking points.", "BACKGROUND OF THE INVENTION Movable windows in general use have sash which are either sliding, double hung or pivotal, with the latter type including awning and casement windows.", "Many different forms of window locks are available for locking a movable window.", "The assignee of the invention disclosed herein markets window locks for such movable windows.", "In many instances, the window can be of such size or of a structural material which renders it desirable to have multi-point locking.", "It is known to mount individual window locks at spaced points or locations on the window to achieve multi-point locking.", "Typically, each of the window locks is independently operable.", "However, the movable mechanisms of a pair of window locks can be connected together for simultaneous movement from a single handle as shown in the Van Klompenburg U.S. Pat. No. 4,095,829, owned by the assignee of this invention.", "Multi-point locking is shown in the Van Benschoten U.S. Pat. No. 2,114,645.", "There are commercially-available multi-point window lock structures operable by a single handle.", "The foregoing prior art does not disclose structure providing for sequential locking of the multi-point locking structure to provide for a delayed lock-up to accommodate racked or warped windows, nor do such structures have a window lock constructed to counteract flexibility of the window structure as may be encountered with a vinyl window.", "SUMMARY OF THE INVENTION A primary feature of the invention is to provide a window lock having improved locking functions for locking a window sash to a window frame and, more particularly, to a window lock constructed to provide for multi-point locking to lock a window sash to a window frame at spaced locations, with delayed lock-up of one lock structure relative to the other to accommodate racked or warped windows and with the structure also taking into account other considerations which may arise in locking of a window having some flexure, such as a vinyl window.", "Additional features of the invention relate to the versatility of the window lock in providing for simple, selective assembly of components to achieve the desired number of locking points;", "the assurance that the window lock mechanism cannot move by any force applied thereto other than by an operating handle;", "the sealing of a window lock housing to the window frame to render the window lock light, water and airtight;", "and an arrangement of the operating mechanism operable by the handle whereby the handle can have two limit positions wherein, in one limit position, the handle establishes a locked condition of the window with the handle close to the window frame and, in going to the other limit position, wherein the window is unlocked, the handle has moved through an arc approaching 180° wherein there is limited protrusion of the handle outwardly of the housing when the window is unlocked.", "An object of the invention is to provide a new and improved window lock.", "Another object of the invention is to provide a new and improved multi-point window lock and, more particularly, such a window lock for vinyl windows.", "A further object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window;", "the improvement comprising: multi-point locking of the window sash to the window frame by utilization of at least two of said ramped keepers and two of said cam members, each of said ramped keepers having an inclined ramp section and a generally planar section, and said slider having a length of movement along said path greater than that required to move a cam member along said ramp section and onto a generally planar section of a ramped keeper whereby delayed lock-up of one cam member and associated ramped keeper may be achieved relative to the other cam member and ramped keeper by having said ramped keepers at a distance apart greater than the distance between said cam members and a planar section of a ramped keeper having a length greater than said difference in distances.", "Still another object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window;", "the improvement comprising: a housing;", "a handle rotatably mounted on said housing for movement between two limit positions and operable to move said slider along said path and said slider and handle having coacting means to preclude gravity or other outside force from moving said slider along said path without moving said handle.", "An additional object of the invention is to provide a window lock for a window having a window frame and a movable window sash comprising, a slider having a cam member, a ramped keeper, and means for moving the slider in a path extending lengthwise thereof to cause the cam member to coact with the ramped keeper in establishing either a locked or unlocked condition of the window;", "the improvement comprising: each of said cam member and ramped keeper being bevelled to resist any separating movement in a direction normal to said path as a result of flexibility of the window frame and window sash as may result due to high loads.", "DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, perspective view of a window shown in open position and which has the window lock structure of FIGS. 2-7 associated therewith;", "FIG. 2 is a side elevation of the window lock hardware shown without association with the window sash and window frame and with the window lock in unlocked position and being a view generally similar to that of FIG. 3 and with parts broken away;", "FIG. 3 is a view similar to FIG. 2 showing the window lock hardware in window-locking position and with the view being taken generally along the line 3--3 in FIG. 4;", "FIG. 4 is a sectional view taken generally along the line 4--4 in FIG. 10;", "and showing the structure in association with the window frame and window sash;", "FIG. 5 is a view similar to FIG. 4 and taken generally along the line 5--5 in FIG. 10;", "FIG. 6 is a fragmentary diagrammatic view of a part of the structure as positioned as shown in FIG. 2 and illustrating a first toggle position;", "FIG. 7 is a view similar to FIG. 6 and illustrating a second toggle position for the structure in window lock position and as shown in FIG. 3;", "FIG. 8 is a fragmentary elevation of the housing;", "FIG. 9 is an elevation view of the handle;", "and FIG. 10 is a fragmentary, perspective view of a window shown in the closed position having the window lock structure of FIGS. 2-7 associated therewith.", "DESCRIPTION OF THE PREFERRED EMBODIMENT The window lock is shown in association with a window in FIG. 1 and with the only room-visible part thereof being a housing 10 and a handle 12.", "The window has a window frame, indicated generally at 14, in which the window sash, generally indicated at 16, of a casement window is pivotally mounted.", "The mounting of such a window by hinges is well known in the art as well as use of a window operator, indicated generally at 18, for moving the window sash between closed and fully open positions or any desired position therebetween.", "As will be readily recognized, the window lock can also be used for an awning-type window wherein the pivotal movement of the window sash would be generally about a horizontal axis, rather than the vertical axis of the casement window.", "The concepts embodied in the window lock could be utilized with other types of movable windows, such as a double hung window.", "The window lock has particular utility with a vinyl window and an embodiment of a vinyl window is shown fragmentarily in FIGS. 4 and 5.", "The window frame 14 has vertical wall sections 20 and 22 suitably integrally interconnected by interconnecting walls and with a pair of interconnected vertical walls 24 and 26 extending at right angles thereto and with the wall 26 defining a room-facing surface of the window frame.", "The window sash 16 has a vertical exterior wall 28 with integrally associated walls including a wall 30 extending normal thereto which defines one of the walls mounting a vertical face panel 32 which can be brought closely adjacent to the vertical frame wall 24 when the window is closed and with a suitable weather strip 34 assuring a tight seal.", "The window lock has a slider 40 movable in a path extending lengthwise thereof and which mounts a cam member, in the form of a roller 42.", "The slider 40 is movable in said path by its mounting on a planar part of a bracket 44 which mounts a pair of shouldered guide rivets 46 and 48 which extend through the respective slider slots 50 and 52, respectively, and which enable movement of the slider from the window unlocked position, shown in FIG. 2, to the window locked position, shown in FIG. 3. The bracket 44 has a pair of bracket flanges 54 and 56 at right angles to the planar part thereof which can receive a pair of fasteners 58 and 60, respectively, which thread into a pair of alignment bosses 62 and 64 extending inwardly from the housing 10 and which fit into a slot formed in the walls 24 and 26 of the window frame.", "The inner face of the housing 10 extends beyond the perimeter of the opening in the window frame to abut against the interior room face of the vertical frame wall 26.", "The fasteners 58 and 60 can draw the bracket flanges 54 and 56 against the inner face of the frame wall 24 and the perimeter of the housing 10 against the wall 26 to capture the window frame therebetween.", "The perimeter part of the housing which bears against the wall 26 includes a continuous O-ring groove, parts of which are shown at 66 and 68 and which receive an O-ring to effect a light, water and airtight seal between the housing and the window frame.", "The housing 10 rotatably mounts the handle 12 for movement between two limit positions.", "One of these limit positions is the window locked position, as shown in FIG. 3, wherein the handle 12 extends doWnwardly and generally parallel to the frame wall 26.", "The handle can move to its other limit position, as seen in FIG. 2, which is the window unlocked position.", "This movement of the handle is through an arc approaching 180° whereby the handle, as seen in FIG. 2, barely extends beyond the housing 10 and, thus, does not protrude into the room when the window is open.", "The slider 40 and handle 12 have coacting means whereby rotation of the handle results in linear movement of the slider along the path lengthwise of the slider.", "This coacting means comprises a drive link 70 splined to the handle at its rotation axis and which has a pin 72 which coacts with a forked section of the slider.", "This forked section has a pair of tines 74 and 76 with an open-ended slot therebetween.", "With the window lock in locked condition and with the handle 12 in the position shown in FIG. 3, the handle can be rotated in a counterclockwise direction to the position shown in FIG. 2 and, during this rotation, the pin 72 will move sequentially inwardly and outwardly of the slot and in engagement with the tine 76 to move the slider 40 downwardly, as viewed in FIGS. 2 and 3.", "In return of the handle 12 to the position of FIG. 3, the handle 12 is rotated clockwise and the pin 72 moves sequentially inwardly and outwardly of the slot and coacts with an edge of the tine 74 to raise the slider, as viewed in FIGS. 2 and 3.", "The planar part of the bracket 44 has an arcuate cut-out 80 to permit the free end of the drive link 70 to move between the positions shown in FIGS. 2 and 3.", "The ends of the tines 74 and 76 of the forked section of the slider are bevelled to enable movement of the drive link 70 to a toggle position in either of the limit positions of the handle.", "This is diagrammatically illustrated in FIGS. 6 and 7.", "With the handle 12 moving to the window unlocked position of FIG. 2, the drive pin 72 moves in a counterclockwise direction, as viewed in FIG. 6, and the downward arc to a toggle position is permitted by the bevelled end 82 of the tine 76.", "The pin 72 has reached a toggle position wherein, if an upward force is exerted on the slider 40 as indicated by the upwardly-directed arrow, the bevelled end 82 of the tine 76 engages the pin 72 and tends to move the pin toward the right.", "This movement is prevented by coaction between the housing and the handle.", "This coaction is achieved by structure shown in FIGS. 8 and 9.", "FIG. 8 shows a side wall 83 of the housing 10 having an opening 84 to receive a stem 85 (FIG.", "9) of the handle 12.", "A pair of abutments 86a and 86b are formed on the housing to define rotatable limit positions for the handle 12 by coaction with an arcuate rib 87 on the handle.", "The rib 87 has an included arc of approximately 104°, although not intended to be limiting, and the abutments 86a and 86b are spaced apart through an angular distance of approximately 250° whereby the handle can rotate through an arc of approximately 150°.", "A similar toggle position is achieved when the handle 12 is in window locked position.", "As seen in FIG. 7, any downward force applied on the slider 40, as represented by the downwardly-directed arrow, would cause a bevelled end 88 of the tine 74 to engage the drive pin 72 and urge the drive link 70 in a clockwise direction, as indicated by the arrow, which would be prevented by coaction of the handle 12 with the housing 10.", "The slider 40 cannot be moved by any outside force other than by handle movement.", "The previously-mentioned cam member on the slider 40, which is the roller 42, coacts with a ramped keeper 100 which is mounted by suitable means to the vertical wall 30 of the window sash.", "The ramped keeper has an inclined ramp section 102 and a generally planar section 104.", "The ramped keeper 100 is shown in FIG. 2 in relation to the roller 42 when the window sash is not fully closed.", "With clockwise rotation of the handle 12 toward the locked position shown in FIG. 3, the slider 40 moves upwardly and the roller 42 engages the inclined ramp section 102 and rolls therealong to draw and maintain the window sash fully closed when the roller 42 moves onto the generally planar section 100 of the ramped keeper.", "The ramped keeper can be a solid member, as shown, or can be shaped from a metal plate.", "In order to achieve multi-point locking, the window sash mounts a second ramped keeper 110 having the same construction as the ramped keeper 100 and at a distance therefrom A second cam member, in the form of a roller 112, coacts with the ramped keeper 110.", "This roller 112 is rotatably-mounted on a tie bar 114 which is connected to an end of the slider 40 for lengthwise movement therewith.", "An upper end of the tie bar is movable within a tie bar guide 116 which is fastened to the frame wall 20 by fasteners 118.", "Versatility in the location of points of locking is achieved by the manner in which a tie bar 114 may be associated with the slider 40.", "The tie bar 114 has a slot 120 at the lower end thereof which extends lengthwise of the tie bar.", "A tie bar rivet 122 is fixed to an offset upper end of the slider 40 and has a pair of aligned ears at a distance from the slider.", "With the tie bar 114 at an angle to the slider, the slot 120 can be aligned with the aligned ears of the tie bar rivet and the tie bar then moved past the ears and, thereafter, rotated to an alignment position, with the aligned ears then locking the tie bar 114 to the slider.", "There is also a tie bar rivet 124 at the lower end of the slider.", "The tie bar 114 can thus extend downwardly from the slider 40.", "Two tie bars can be used.", "Further variations can be achieved by the use of additional rollers with each tie bar (and additional ramped keepers) and the use of varying length tie bars.", "The multi-point locking is achieved with delayed lock-up of the roller 112 and ramp keeper 110 relative to the roller 42 and ramped keeper 100 by the slider having a length of movement along its path greater than that required to move a roller along the inclined ramp section 102 and onto a generally planar section 104 of a ramped keeper and having the ramped keepers at a distance apart greater than the distance between the rollers.", "A generally planar section of a ramped keeper has a length greater than the differences in the distances to provide a dwell for one roller while the other roller is on an inclined ramp section.", "An added feature with particular utility for a vinyl window because of the flexibility thereof is the bevelling of the rollers 42 and 112 and the generally planar sections 104 of the ramped keepers, as seen in FIGS. 4 and 5, to resist separation therebetween in a direction normal to the path of the slider 40.", "Referring more particularly to FIG. 4, any tendency of the window sash to move toward the left, which would cause separation between the ramped keeper and the roller, is resisted by the bevelled relation therebetween.", "The sequential locking action at the multiple lock points has a further advantage in limiting the maximum amount of force required at any one time to achieve the full locking of the window.", "From the foregoing, it will be evident that a window lock with extreme versatility and providing for multi-point locking has been provided.", "With the structure of the ramped keepers having the elongate generally planar sections providing an elongate dwell, there is an enhanced versatility in that the ramped keepers can be located in a desired relation to achieve the desired sequence of locking at various locking points.", "The tie bars can be provided in different lengths and with different numbers of rollers thereon and the desired tie bars can readily be associated with the slider at either the top or bottom thereof with the simple rotation connection which does not require the use of any attaching screws between the tie bar and the slider." ]
BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to a stacked gate flash memory cell structure and process which uses a large angle ion implant beam to form the source and drain regions in the cell. A low doped region is formed between the edge of either the source or drain and the edge of the first gate electrode. The tunnel dielectric is grown over this low doped region and is self-aligned with it. This method provides a self-aligned very small tunnel dielectric area. (2) Description of Related Art Conventional stacked gate flash memory cell structures have the disadvantage of a large tunnel dielectric area which requires large voltages for programming and erase operations of the memory cell. In addition larger tunnel dielectric areas introduce more defects and lower device yield. Often the tunnel dielectric is the same dielectric as the gate dielectric which leads to a compromise between gate dielectric thickness and tunnel oxide thickness. This invention has the advantage of a tunnel dielectric which is independent of the gate dielectric and the thickness of each can be optimized. In this invention the tunnel dielectric is self-aligned to the source and gate and has a width that can be accurately controlled. SUMMARY OF THE INVENTION It is a principle object of the invention to provide a method of forming a stacked gate flash memory cell with a smaller tunnel dielectric area than can be achieved using conventional processing. It is another object of the invention to provide a stacked gate flash memory cell with smaller tunnel dielectric area than can be achieved using conventional methods. A smaller tunnel dielectric area requires a lower voltage for programming and erasing operations in the memory cell. A smaller tunnel dielectric area also reduces defects and improves device yield. These objectives are achieved by using a self-aligned method of forming the tunnel dielectric region which permits the tunnel dielectric region to be kept small while maintaining critical dimensional tolerances. A oblique angle ion implant beam is used to form the N + source and drain regions of the flash memory cell using the first gate electrode as a mask. This results in either the source or drain region extending under one edge of the first gate electrode and a gap width between an edge of either the source or drain region, whichever does not extend under the first gate electrode, and an edge of the first gate electrode. Normally directed ion implantation is then used to form an N - low doped region in the gap width. The width of the low doped region can be accurately controlled by adjusting the angle of the oblique angle ion implant beam. There is no wafer rotation when the oblique angle ion implant beam is used. A thermal oxide is then grown which will become the tunnel dielectric or tunnel oxide region and a self-aligned thick oxide region. The thermal oxide grows faster over the N + source and drain regions than over the N - light doped region. The tunnel oxide is the thin oxide formed over the light doped region. The width of the tunnel oxide is controlled by the width of the light doped region. The width of the light doped region is accurately controlled by the angle of the large angle ion implant beam. The accuracy with which the width of the tunnel oxide region can be controlled and the self-aligned nature of the tunnel oxide region are both important in achieving a very small tunnel oxide width. The flash memory cell uses a floating gate and a control gate structure. When a suitable potential is applied to the control gate, which is also the Word line, while grounding the source or drain, whichever is formed adjacent to the light doped region, electrons are injected into the floating gate from the source or drain, whichever is formed adjacent to the light doped region, through the tunnel oxide. When a suitable potential is applied to the source or drain, whichever is formed adjacent to the light doped region, while grounding the control gate electrons are injected from the floating gate into the source or drain, whichever is formed adjacent to the light doped region, through the tunnel oxide. Smaller tunnel oxide areas require smaller voltages for the programming and erase operations just described. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a cross section view of the flash memory cell after formation of the first gate electrode with a nitride layer. FIG. 2A is a cross section view of the flash memory cell after formation of the first gate electrode with the nitride layer showing the large angle ion implant beam used to form the source and drain regions. FIG. 2B is a cross section view of the flash memory cell showing the formation of the source and drain regions using the large angle ion implant beam. FIG. 3A is a cross section view of the flash memory cell showing the formation of the light doped region using normally directed ion implantation. FIG. 3B is a top view of the flash memory cell after formation of the source, drain, and light doped regions. FIG. 4 is a cross section view of the flash memory cell showing the formation of the tunnel oxide, self-aligned thick oxide, and sidewall oxide regions. FIG. 5 is a cross section of the flash memory cell after the second gate electrode material has been formed. FIG. 6A is a cross section view of the flash memory cell after the second gate electrode has been formed, the oxide/nitride/oxide layer has been formed, and the control gate electrode or word line has been formed. FIG. 6B is a top view of the flash memory cell showing the first gate electrode, the second gate electrode, the control gate electrode, the source, the drain, and the light doped regions. FIG. 7 is a cross section view of the flash memory cell after the insulating dielectric layer and contacts to the control gate electrode have been formed. DESCRIPTION OF THE PREFERRED EMBODIMENTS Refer now to FIG. 1 through FIG. 7, there is shown the principle embodiment for the method of forming the flash memory cell with self-aligned tunnel dielectric area. FIG. 1 shows a P type silicon substrate 20 with a layer of gate oxide 30, such as SiO 2 , with a thickness of between about 200 Angstroms and 1000 Angstroms formed on the silicon substrate 20. A polysilicon first gate electrode 40 is formed on the layer of gate oxide and a nitride layer 42 is formed on the first gate electrode. At this stage of the process the first gate electrode 40 extends over a number of adjacent memory cells in order to serve as a mask for the formation of the source, drain, and light doped regions. The first gate electrode will be modified later to be isolated to a single cell. The first gate electrode and nitride layer are formed by means of conventional deposition, photoresist, lithography, and etching methods. Examples of these conventional methods can be found in the book "VLSI PROCESS TECHNOLOGY" Second Edition, by S. M. Sze, published by McGraw-Hill Book Co., New York, N.Y., 1988, pages 221-226 and 223-245. This embodiment describes a stacked gate flash memory cell where the drain region extends under an edge of the first gate electrode and a gap width is formed between the edge of the source region nearest the first gate and the edge of the first gate electrode nearest the source region. The invention works equally well if the source and drain regions are interchanged. Next, as shown in FIG. 2A, a large angle ion implant beam 50 is used to form the source and drain regions. The oblique angle ion implant beam forms an angle 52 of between about 10° and 60° between the beam direction and the sidewall of the first gate electrode. As shown in FIG. 2B N + source 22 and drain 24 regions are formed using a large angle ion implant beam 50 of arsenic ions with between about 1×10 15 and 8×10 15 ions/cm 2 at between about 30 and 100 keV. There is no wafer rotation during this implantation step. As shown in FIG. 2B, one edge of the drain 24 region extends under the edge of the first gate electrode 40 nearest the drain 24 region. There is a gap width 56 between the edge of the first gate electrode 40 nearest the source 22 region and the nearest edge of the source 22 region. The gap width 56 is the tunnel oxide dimension and is between about 0.1 microns and 0.3 microns. The gap width 56 is very nearly equal to the height 54 of the first gate electrode 40 with the nitride layer 42 multiplied by the tangent of the angle 40 between the oblique angle ion beam 50 and the sidewall of the first gate electrode 40. Next, as shown in FIG. 3A, the gate oxide layer not covered by the first gate electrode is removed by etching using the first gate electrode 40 with the nitride layer 42 as a mask. Next, the N - light doped region 26 is formed between the edge of the first gate electrode 40 nearest the source 22 region and the nearest edge of the source 22 region. The light doped drain region is formed using a normally directed ion beam 52 of phosphorous or arsenic with between about 1×10 13 and 1×10 14 ions/cm 2 at between about 30 and 50 keV. The edge of the first gate electrode 40 serves as a mask to determine one edge of the light doped region. FIG. 3B shows the top view of the flash memory cell at this stage of formation showing the first gate electrode 40, the source region 22, the drain region 24, and the light doped drain region 26. Next, as shown in FIG. 4, the side wall oxide 34, the tunnel oxide 32, and the self-aligned thick oxide 36 are formed using thermal oxidation at between about 800° C. and 950° C. The tunnel oxide 32 is between about 60 Angstroms and 100 Angstroms thick. The self-aligned thick oxide is grown at the same time as the tunnel oxide but since it is formed on an N + region the self-aligned thick oxide grows faster than the tunnel oxide which is formed on an N - region. The self-aligned thick oxide thickness is between about 200 Angstroms and 500 Angstroms. The tunnel oxide and the self-aligned thick oxide are formed independently of the gate oxide so that the thickness of the gate oxide and the tunnel oxide can both be optimized. Since the self-aligned thick oxide and the tunnel oxide regions are determined by the material they are grown on the self-aligned thick oxide is self aligned to the tunnel oxide and the width of the tunnel oxide region is automatically controlled. Next, as shown in FIG. 5, the nitride layer is removed from the first gate electrode and a second polysilicon layer 46 is formed on the silicon substrate using conventional means. The second polysilicon layer 46 forms electrical contact with the first gate electrode 40. Next, as shown in FIG. 6A, the second gate electrode 46 is formed by patterning the second polysilicon layer using conventional means of photoresist, lithography and etching. The first gate electrode 40 is electrically shorted to the second gate electrode 46 and together they will form the floating gate. Next a layer of oxide/nitride/oxide 47 with an effective thickness of between about 100 Angstroms and 300 Angstroms is formed over the second gate electrode by means of conventional chemical vapor deposition and/or thermal oxidation methods. Next a control polysilicon layer is formed on the layer of oxide/nitride/oxide 47. The control gate electrode or word line 48 is then formed by patterning the control polysilicon layer using conventional means of photoresist, lithography and etching. The floating gate is formed from the electrically shorted first gate electrode and second gate electrode and must not extend from one cell to another but must be isolated to a single cell. The etching of the control polysilicon layer to form the control gate electrode or word line is continued through the first and second polysilicon layers to achieve this isolation. Examples of such conventional means are given in the previously cited book by Sze, pages 221-226 and 233-245. FIG. 6B shows the top view of two adjacent flash memory cells showing the word lines 48 at right angles to the source region 22, the drain region 24, and the light doped region 26; and the separation of the floating gate between cells. Next, as shown in FIG. 7, the flash memory cell is completed by forming an insulation layer such as borophosphosilicate glass 70 over the silicon substrate. Contact openings are formed in the insulation layer to form metal contacts 72 to the word lines 48. A patterned metal conductor layer and a passivation dielectric layer, not shown, are formed on the silicon substrate to complete the formation of the stacked gate flash memory cell device. These completion operations can be accomplished using conventional means. Refer now to FIG. 6B and FIG. 7, there is shown an embodiment of the flash memory cell with a self aligned tunnel dielectric area. FIG. 7 shows a cross section view of the flash memory cell. The P type silicon substrate 20 has N + source 22 and drain 24 regions formed therein. One edge of the drain 24 region extends under the polysilicon first gate electrode 40. This embodiment describes a stacked gate flash memory cell where the drain region extends under an edge of the first gate electrode and a gap width is formed between the edge of the source region nearest the first gate and the edge of the first gate electrode nearest the source region. The invention works equally well if the source and drain regions are interchanged. There is an N - light doped region 26 between the edge of the source 22 region nearest the first gate electrode 40 and the edge of the first gate electrode. There is a tunnel oxide area 32, such as SiO 2 with a thickness of between about 60 Angstroms and 100 Angstroms, formed directly over the light doped region 26. A self-aligned thick oxide 36, such as SiO 2 with a thickness of between about 200 Angstroms and 500 Angstroms, is formed directly over the source 22 region and that part of the drain 24 region which is not under the first gate electrode. A gate oxide 25, such as SiO 2 with a thickness of between about 200 Angstroms and 1000 Angstroms, is formed on the silicon substrate and a polysilicon first gate electrode 40, with a thickness of between about 1000 Angstroms and 5000 Angstroms, is formed on the gate oxide 30. A polysilicon second gate electrode 46, with a thickness of between about 500 and 2000 Angstroms, is formed over the first gate electrode 40 after the tunnel oxide 32 and self-aligned thick oxide 36 have been formed and extends over the tunnel oxide 32 and over a portion of the self-aligned thick oxide 36 on both sides of the first gate electrode 40. The second gate electrode 46 makes electrical contact with the first gate electrode 40. A sidewall oxide 34 is formed on the sidewalls of the first gate electrode. A layer of oxide/nitride/oxide 47 with a thickness of between about 100 and 300 Angstroms is formed on the second gate electrode 46. A polysilicon control gate electrode 48, with a thickness of between about 2000 Angstroms and 5000 Angstroms, is formed over the oxide/nitride/oxide 47 layer. The control gate electrode 48 is the word line. FIG. 6B shows a top view of the flash memory cell. The word line 48 is at right angles to the source 22, the drain 24, and the light doped drain region. Refer again to FIG. 7, an insulating dielectric layer 70, such a borophosphosilicate glass, is formed over the silicon substrate after the word lines 48 have been formed and metal contacts 72 are formed through the insulating dielectric layer 70 to the word line 48. No electrical contact is made to the floating gate, formed from the electrically shorted first gate electrode 40 and second gate electrode 46, and the floating gate for each stacked gate flash memory cell is separate from the floating gates for other stacked gate flash memory cells. A patterned conducting metal layer and passivation dielectric layer, not shown, complete the formation of the flash memory cell. Referring again to FIG. 7, the first gate electrode 40 and the second gate electrode 46 are electrically connected together and form the floating gate of the flash memory cell. The control gate electrode 48 forms the word line. When a suitable potential is applied to the word line 48 while grounding the source 22 electrons are injected into the floating gate, first gate electrode 40 and second gate electrode 46, from the source 22 through the tunnel oxide 32. When a suitable potential is applied to the source 22 while grounding the word line 48 electrons are injected from the floating gate, first gate electrode 40 and second gate electrode 46, into the source 22 through the tunnel oxide 32. Smaller areas of the tunnel oxide region require lower voltages for the writing and erasing operations just described. While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.
This invention provides a stacked gate flash memory cell structure and a method for forming the stacked gate flash memory structure. The invention uses a large angle ion implant beam without wafer rotation to form the source and drain regions of the memory cell. A low doped region is formed between an edge of the first gate electrode and an edge of either the source or drain regions. The tunnel dielectric is formed directly above the low doped region. The width of the low doped region is controlled by the angle of the large angle ion implant beam and can be very accurately controlled. The tunnel dielectric is formed independently of the gate dielectric and the thickness of each can be optimized. The tunnel dielectric area can be made very small which improves reliability and reduces the voltage necessary to program and erase the memory cell.
Briefly outline the background technology and the problem the invention aims to solve.
[ "BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to a stacked gate flash memory cell structure and process which uses a large angle ion implant beam to form the source and drain regions in the cell.", "A low doped region is formed between the edge of either the source or drain and the edge of the first gate electrode.", "The tunnel dielectric is grown over this low doped region and is self-aligned with it.", "This method provides a self-aligned very small tunnel dielectric area.", "(2) Description of Related Art Conventional stacked gate flash memory cell structures have the disadvantage of a large tunnel dielectric area which requires large voltages for programming and erase operations of the memory cell.", "In addition larger tunnel dielectric areas introduce more defects and lower device yield.", "Often the tunnel dielectric is the same dielectric as the gate dielectric which leads to a compromise between gate dielectric thickness and tunnel oxide thickness.", "This invention has the advantage of a tunnel dielectric which is independent of the gate dielectric and the thickness of each can be optimized.", "In this invention the tunnel dielectric is self-aligned to the source and gate and has a width that can be accurately controlled.", "SUMMARY OF THE INVENTION It is a principle object of the invention to provide a method of forming a stacked gate flash memory cell with a smaller tunnel dielectric area than can be achieved using conventional processing.", "It is another object of the invention to provide a stacked gate flash memory cell with smaller tunnel dielectric area than can be achieved using conventional methods.", "A smaller tunnel dielectric area requires a lower voltage for programming and erasing operations in the memory cell.", "A smaller tunnel dielectric area also reduces defects and improves device yield.", "These objectives are achieved by using a self-aligned method of forming the tunnel dielectric region which permits the tunnel dielectric region to be kept small while maintaining critical dimensional tolerances.", "A oblique angle ion implant beam is used to form the N + source and drain regions of the flash memory cell using the first gate electrode as a mask.", "This results in either the source or drain region extending under one edge of the first gate electrode and a gap width between an edge of either the source or drain region, whichever does not extend under the first gate electrode, and an edge of the first gate electrode.", "Normally directed ion implantation is then used to form an N - low doped region in the gap width.", "The width of the low doped region can be accurately controlled by adjusting the angle of the oblique angle ion implant beam.", "There is no wafer rotation when the oblique angle ion implant beam is used.", "A thermal oxide is then grown which will become the tunnel dielectric or tunnel oxide region and a self-aligned thick oxide region.", "The thermal oxide grows faster over the N + source and drain regions than over the N - light doped region.", "The tunnel oxide is the thin oxide formed over the light doped region.", "The width of the tunnel oxide is controlled by the width of the light doped region.", "The width of the light doped region is accurately controlled by the angle of the large angle ion implant beam.", "The accuracy with which the width of the tunnel oxide region can be controlled and the self-aligned nature of the tunnel oxide region are both important in achieving a very small tunnel oxide width.", "The flash memory cell uses a floating gate and a control gate structure.", "When a suitable potential is applied to the control gate, which is also the Word line, while grounding the source or drain, whichever is formed adjacent to the light doped region, electrons are injected into the floating gate from the source or drain, whichever is formed adjacent to the light doped region, through the tunnel oxide.", "When a suitable potential is applied to the source or drain, whichever is formed adjacent to the light doped region, while grounding the control gate electrons are injected from the floating gate into the source or drain, whichever is formed adjacent to the light doped region, through the tunnel oxide.", "Smaller tunnel oxide areas require smaller voltages for the programming and erase operations just described.", "BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a cross section view of the flash memory cell after formation of the first gate electrode with a nitride layer.", "FIG. 2A is a cross section view of the flash memory cell after formation of the first gate electrode with the nitride layer showing the large angle ion implant beam used to form the source and drain regions.", "FIG. 2B is a cross section view of the flash memory cell showing the formation of the source and drain regions using the large angle ion implant beam.", "FIG. 3A is a cross section view of the flash memory cell showing the formation of the light doped region using normally directed ion implantation.", "FIG. 3B is a top view of the flash memory cell after formation of the source, drain, and light doped regions.", "FIG. 4 is a cross section view of the flash memory cell showing the formation of the tunnel oxide, self-aligned thick oxide, and sidewall oxide regions.", "FIG. 5 is a cross section of the flash memory cell after the second gate electrode material has been formed.", "FIG. 6A is a cross section view of the flash memory cell after the second gate electrode has been formed, the oxide/nitride/oxide layer has been formed, and the control gate electrode or word line has been formed.", "FIG. 6B is a top view of the flash memory cell showing the first gate electrode, the second gate electrode, the control gate electrode, the source, the drain, and the light doped regions.", "FIG. 7 is a cross section view of the flash memory cell after the insulating dielectric layer and contacts to the control gate electrode have been formed.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS Refer now to FIG. 1 through FIG. 7, there is shown the principle embodiment for the method of forming the flash memory cell with self-aligned tunnel dielectric area.", "FIG. 1 shows a P type silicon substrate 20 with a layer of gate oxide 30, such as SiO 2 , with a thickness of between about 200 Angstroms and 1000 Angstroms formed on the silicon substrate 20.", "A polysilicon first gate electrode 40 is formed on the layer of gate oxide and a nitride layer 42 is formed on the first gate electrode.", "At this stage of the process the first gate electrode 40 extends over a number of adjacent memory cells in order to serve as a mask for the formation of the source, drain, and light doped regions.", "The first gate electrode will be modified later to be isolated to a single cell.", "The first gate electrode and nitride layer are formed by means of conventional deposition, photoresist, lithography, and etching methods.", "Examples of these conventional methods can be found in the book "VLSI PROCESS TECHNOLOGY"", "Second Edition, by S. M. Sze, published by McGraw-Hill Book Co., New York, N.Y., 1988, pages 221-226 and 223-245.", "This embodiment describes a stacked gate flash memory cell where the drain region extends under an edge of the first gate electrode and a gap width is formed between the edge of the source region nearest the first gate and the edge of the first gate electrode nearest the source region.", "The invention works equally well if the source and drain regions are interchanged.", "Next, as shown in FIG. 2A, a large angle ion implant beam 50 is used to form the source and drain regions.", "The oblique angle ion implant beam forms an angle 52 of between about 10° and 60° between the beam direction and the sidewall of the first gate electrode.", "As shown in FIG. 2B N + source 22 and drain 24 regions are formed using a large angle ion implant beam 50 of arsenic ions with between about 1×10 15 and 8×10 15 ions/cm 2 at between about 30 and 100 keV.", "There is no wafer rotation during this implantation step.", "As shown in FIG. 2B, one edge of the drain 24 region extends under the edge of the first gate electrode 40 nearest the drain 24 region.", "There is a gap width 56 between the edge of the first gate electrode 40 nearest the source 22 region and the nearest edge of the source 22 region.", "The gap width 56 is the tunnel oxide dimension and is between about 0.1 microns and 0.3 microns.", "The gap width 56 is very nearly equal to the height 54 of the first gate electrode 40 with the nitride layer 42 multiplied by the tangent of the angle 40 between the oblique angle ion beam 50 and the sidewall of the first gate electrode 40.", "Next, as shown in FIG. 3A, the gate oxide layer not covered by the first gate electrode is removed by etching using the first gate electrode 40 with the nitride layer 42 as a mask.", "Next, the N - light doped region 26 is formed between the edge of the first gate electrode 40 nearest the source 22 region and the nearest edge of the source 22 region.", "The light doped drain region is formed using a normally directed ion beam 52 of phosphorous or arsenic with between about 1×10 13 and 1×10 14 ions/cm 2 at between about 30 and 50 keV.", "The edge of the first gate electrode 40 serves as a mask to determine one edge of the light doped region.", "FIG. 3B shows the top view of the flash memory cell at this stage of formation showing the first gate electrode 40, the source region 22, the drain region 24, and the light doped drain region 26.", "Next, as shown in FIG. 4, the side wall oxide 34, the tunnel oxide 32, and the self-aligned thick oxide 36 are formed using thermal oxidation at between about 800° C. and 950° C. The tunnel oxide 32 is between about 60 Angstroms and 100 Angstroms thick.", "The self-aligned thick oxide is grown at the same time as the tunnel oxide but since it is formed on an N + region the self-aligned thick oxide grows faster than the tunnel oxide which is formed on an N - region.", "The self-aligned thick oxide thickness is between about 200 Angstroms and 500 Angstroms.", "The tunnel oxide and the self-aligned thick oxide are formed independently of the gate oxide so that the thickness of the gate oxide and the tunnel oxide can both be optimized.", "Since the self-aligned thick oxide and the tunnel oxide regions are determined by the material they are grown on the self-aligned thick oxide is self aligned to the tunnel oxide and the width of the tunnel oxide region is automatically controlled.", "Next, as shown in FIG. 5, the nitride layer is removed from the first gate electrode and a second polysilicon layer 46 is formed on the silicon substrate using conventional means.", "The second polysilicon layer 46 forms electrical contact with the first gate electrode 40.", "Next, as shown in FIG. 6A, the second gate electrode 46 is formed by patterning the second polysilicon layer using conventional means of photoresist, lithography and etching.", "The first gate electrode 40 is electrically shorted to the second gate electrode 46 and together they will form the floating gate.", "Next a layer of oxide/nitride/oxide 47 with an effective thickness of between about 100 Angstroms and 300 Angstroms is formed over the second gate electrode by means of conventional chemical vapor deposition and/or thermal oxidation methods.", "Next a control polysilicon layer is formed on the layer of oxide/nitride/oxide 47.", "The control gate electrode or word line 48 is then formed by patterning the control polysilicon layer using conventional means of photoresist, lithography and etching.", "The floating gate is formed from the electrically shorted first gate electrode and second gate electrode and must not extend from one cell to another but must be isolated to a single cell.", "The etching of the control polysilicon layer to form the control gate electrode or word line is continued through the first and second polysilicon layers to achieve this isolation.", "Examples of such conventional means are given in the previously cited book by Sze, pages 221-226 and 233-245.", "FIG. 6B shows the top view of two adjacent flash memory cells showing the word lines 48 at right angles to the source region 22, the drain region 24, and the light doped region 26;", "and the separation of the floating gate between cells.", "Next, as shown in FIG. 7, the flash memory cell is completed by forming an insulation layer such as borophosphosilicate glass 70 over the silicon substrate.", "Contact openings are formed in the insulation layer to form metal contacts 72 to the word lines 48.", "A patterned metal conductor layer and a passivation dielectric layer, not shown, are formed on the silicon substrate to complete the formation of the stacked gate flash memory cell device.", "These completion operations can be accomplished using conventional means.", "Refer now to FIG. 6B and FIG. 7, there is shown an embodiment of the flash memory cell with a self aligned tunnel dielectric area.", "FIG. 7 shows a cross section view of the flash memory cell.", "The P type silicon substrate 20 has N + source 22 and drain 24 regions formed therein.", "One edge of the drain 24 region extends under the polysilicon first gate electrode 40.", "This embodiment describes a stacked gate flash memory cell where the drain region extends under an edge of the first gate electrode and a gap width is formed between the edge of the source region nearest the first gate and the edge of the first gate electrode nearest the source region.", "The invention works equally well if the source and drain regions are interchanged.", "There is an N - light doped region 26 between the edge of the source 22 region nearest the first gate electrode 40 and the edge of the first gate electrode.", "There is a tunnel oxide area 32, such as SiO 2 with a thickness of between about 60 Angstroms and 100 Angstroms, formed directly over the light doped region 26.", "A self-aligned thick oxide 36, such as SiO 2 with a thickness of between about 200 Angstroms and 500 Angstroms, is formed directly over the source 22 region and that part of the drain 24 region which is not under the first gate electrode.", "A gate oxide 25, such as SiO 2 with a thickness of between about 200 Angstroms and 1000 Angstroms, is formed on the silicon substrate and a polysilicon first gate electrode 40, with a thickness of between about 1000 Angstroms and 5000 Angstroms, is formed on the gate oxide 30.", "A polysilicon second gate electrode 46, with a thickness of between about 500 and 2000 Angstroms, is formed over the first gate electrode 40 after the tunnel oxide 32 and self-aligned thick oxide 36 have been formed and extends over the tunnel oxide 32 and over a portion of the self-aligned thick oxide 36 on both sides of the first gate electrode 40.", "The second gate electrode 46 makes electrical contact with the first gate electrode 40.", "A sidewall oxide 34 is formed on the sidewalls of the first gate electrode.", "A layer of oxide/nitride/oxide 47 with a thickness of between about 100 and 300 Angstroms is formed on the second gate electrode 46.", "A polysilicon control gate electrode 48, with a thickness of between about 2000 Angstroms and 5000 Angstroms, is formed over the oxide/nitride/oxide 47 layer.", "The control gate electrode 48 is the word line.", "FIG. 6B shows a top view of the flash memory cell.", "The word line 48 is at right angles to the source 22, the drain 24, and the light doped drain region.", "Refer again to FIG. 7, an insulating dielectric layer 70, such a borophosphosilicate glass, is formed over the silicon substrate after the word lines 48 have been formed and metal contacts 72 are formed through the insulating dielectric layer 70 to the word line 48.", "No electrical contact is made to the floating gate, formed from the electrically shorted first gate electrode 40 and second gate electrode 46, and the floating gate for each stacked gate flash memory cell is separate from the floating gates for other stacked gate flash memory cells.", "A patterned conducting metal layer and passivation dielectric layer, not shown, complete the formation of the flash memory cell.", "Referring again to FIG. 7, the first gate electrode 40 and the second gate electrode 46 are electrically connected together and form the floating gate of the flash memory cell.", "The control gate electrode 48 forms the word line.", "When a suitable potential is applied to the word line 48 while grounding the source 22 electrons are injected into the floating gate, first gate electrode 40 and second gate electrode 46, from the source 22 through the tunnel oxide 32.", "When a suitable potential is applied to the source 22 while grounding the word line 48 electrons are injected from the floating gate, first gate electrode 40 and second gate electrode 46, into the source 22 through the tunnel oxide 32.", "Smaller areas of the tunnel oxide region require lower voltages for the writing and erasing operations just described.", "While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to an apparatus for compressing video data to transmit moving picture data in real time through a transmission medium with a limited band width, and more particularly to an improved motion vector extractor which is capable of rapidly extracting motion vectors from the moving picture data to be transmitted and simplifying its circuit construction. 2. Description of the Prior Art Recently, digital video transmission systems have utilized a data compression method to transmit moving picture data in real time through a transmission channel with a limited band width to digital video reception systems such as a digital video phone, a digital video conversation system, a digital television and a high definition television. The data compression method is adapted to compress the moving picture data by removing time and spatial redundancies of the moving picture data. The time redundancy removing methods include motion vector estimation and compensation methods for transmitting only motion vectors regarding a moving object or a part of the moving object to have the actual video data transmission effect. This results from the moving picture data having a series of frames corresponding to the moving object. The motion vector estimation method is generally classified into a recursive method and a matching method. In the matching method, there is widely used a block matching algorithm for matching the moving picture data in the unit of block to estimate the motion vectors from the moving picture data. The ISO/IEC JTC1/SC29/WG11 recommendation proposed by the moving picture expert group (MPEG) specifies a block matching algorithm which finds the motion vectors in the unit of macro block including 16×16 pixels. This recommendation also suggests that the motion vectors be estimated in the unit of 1/2 pixel to enhance the accuracy thereof. On the basis of the above recommendation, the digital video transmission systems comprise a motion vector extractor for extracting a motion vector in a pixel unit smaller than an integer, such as 1/4 pixel or 1/2 pixel, to secure the accuracy of the video data to be transmitted. Such a conventional motion vector extractor produces interpolation pixel data using desired integer pixel data and integer pixel data adjacent up, down, to the left and to the right of the desired integer pixel data. The conventional motion vector extractor calculates a mean absolute difference (referred to hereinafter as "MAD") between the desired integer pixel data and each of the produced interpolation pixel data. Then, the conventional motion vector extractor compares the calculated MADs with one another and calculates the motion vector in accordance with the compared result. In the case of estimating the motion vector in the unit of 1/4 pixel, the conventional motion vector extractor must calculate 16 of 49 interpolation pixel data, adjacent to one side of the desired integer pixel data, and the corresponding MADs. In the case of estimating the motion vector in the unit of 1/2 pixel, the conventional motion vector extractor must calculate 4 of 9 interpolation pixel data, adjacent to one side of the desired integer pixel data, and the corresponding MADs. However, the above-mentioned conventional motion vector extractor has a disadvantage in that it sequentially calculates one by one the interpolation pixel data related to the desired integer pixel data, resulting in much time being required in calculating the motion vector. Further, the above-mentioned conventional motion vector extractor has another disadvantage in that it must have a complex circuit construction to enhance the motion vector calculating time. The problem with the above-mentioned conventional motion vector extractor will hereinafter be described in detail with reference to FIGS. 1 to 5. Referring to FIG. 1, there is shown a block diagram of the conventional motion vector extractor for extracting the motion vector in the unit of 1/4 pixel. As shown in this drawing, the conventional motion vector extractor comprises a first interpolation circuit 10 for inputting pixel data b(i,j) of the previous frame (referred to hereinafter as "present pixel data") and pixel data b(i+1,j) of the subsequent block line of the pixel data b(i,j) (referred to hereinafter as "subsequent line pixel data") from first and second input lines 11 and 13, respectively. Here, "i" and "j" designate vertical and horizontal coordinates of the pixel data, respectively. The first interpolation circuit 10 obtains four vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) with respect to the pixel data b(i,j) of the previous frame using the pixel data b(i,j) of the previous frame and the subsequent line pixel data b(i+1,j). Then, the first interpolation circuit 10 sequentially supplies the obtained vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) to a first register 12. The first register 12 sequentially supplies the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) from the first interpolation circuit 10 to a second interpolation circuit 22 and a second register 14. The second to fifth registers 14, 16, 18 and 20 are connected in series to the first register 12 to delay the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) from the first register 12 by a one pixel interval, respectively. As a result, the fifth register 20 sequentially supplies the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) regarding the present pixel data to the second interpolation circuit 22, whereas the first register 12 sequentially supplies vertical interpolation pixel data b 0 0 (i,j+1), b 0 1 (i,j+1), b 0 2 (i,j+1) and b 0 3 (i,j+1) regarding the subsequent pixel data to the second interpolation circuit 22. The second interpolation circuit 22 combines the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) regarding the present pixel data, supplied from the fifth register 20, and the vertical interpolation pixel data b 0 0 (i,j+1), b 0 1 (i,j+1), b 0 2 (i,j+1) and b 0 3 (i,j+1) regarding the subsequent pixel data, supplied from the first register 12. As a result of the combination, the second interpolation circuit 22 obtains four horizontal interpolation pixel data b 0 k (i,j), b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) with respect to each of the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j). The conventional motion vector extractor further comprises first to fourth MAD detectors 24, 26, 28 and 30 for inputting pixel data a (i,j) of the present frame from a third input line 15. The first MAD detector 24 sequentially obtains four MADs in the vertical direction on the basis of the pixel data a (i,j) of the present frame from the third input line 15 and the horizontal interpolation pixel data b 0 k (i,j) from the second interpolation circuit 22. Then, the first MAD detector 24 sequentially supplies the obtained four MADs to a comparator 32. Similarly, each of the second to fourth MAD detectors 26, 28 and 30 obtains four MADs in the vertical direction on the basis of the pixel data a (i,j) of the present frame from the third input line 15 and a corresponding one of the horizontal interpolation pixel data b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) from the second interpolation circuit 22 and then supplies the obtained four MADs to the comparator 32. The comparator 32 compares the MADs from the first to fourth MAD detectors 24, 26, 28 and 30 with one another and detects the motion vector in accordance with the compared result. The second interpolation circuit 22, the first to fourth MAD detectors 24, 26, 28 and 30 and the comparator 32 are operated four times to extract the motion vector regarding one pixel at output line 17. The first and second interpolation circuits 10 and 22 are operated four times to produce 16 interpolation pixel data on the basis of the following equation (1): b.sub.1.sup.k (i,j)=(4-l)/4{(4-k)b(i,j)/4+kb(i+1,j)/4}+l/4{(4-k)b(i,j+1)/4+kb(i+1,j+1)/4}(1) Referring to FIG. 2, there is shown a detailed block diagram of the first interpolation circuit 10 in FIG. 1. As shown in this drawing, the first interpolation circuit 10 includes a first attenuator 34 for inputting the pixel data b(i,j) of the previous frame from the first input line 11, and a second attenuator 36 for inputting the subsequent line pixel data b(i+1,j) from the second input line 13. The second attenuator 36 attenuates the subsequent line pixel data b(i+1,j) from the second input line 13 in such a manner that it can have a 1/4 amplitude. Then, the second attenuator 36 supplies the attenuated subsequent line pixel data b(i+1,j)/4 to a first adder 38. The first adder 38 adds pixel data from a first subtracter 44 to the attenuated subsequent line pixel data b(i+1,j)/4 from the second attenuator 36. As a result of the addition, the first adder 38 obtains the vertical interpolation pixel data b 0 k (i,j). The first adder 38 then supplies the obtained vertical interpolation pixel data b 0 k (i,j) to a multiplexer 40. The multiplexer 40 selectively transfers the vertical interpolation pixel data b 0 k (i,j) from the first adder 38 and the pixel data b(i,j) of the previous frame from the first input line 11 through an output line 35 to the first register 12 in FIG. 1. Namely, at the initial state, the multiplexer 40 transfers the pixel data b(i,j) of the previous frame from the first input line 11 as the vertical interpolation pixel data b 0 k (i,j) through the output line 35 to the first register 12. At the normal state, the multiplexer 40 transfers the vertical interpolation pixel data b 0 k (i,j) from the first adder 38 through the output line 35 to the first register 12. The first interpolation circuit 10 further includes a sixth register 42 for inputting the vertical interpolation pixel data b O k (i,j) selected by the multiplexer 40 through the output line 35. The sixth register 42 delays the vertical interpolation pixel data b O k (i,j) from the multiplexer 40 for a predetermined time period and supplies the delayed vertical interpolation pixel data b O k (i,j) to the first subtracter 44. The first attenuator 34 attenuates the pixel data b(i,j) of the previous frame from the first input line 11 in such a manner that it can have a 1/4 amplitude. Then, the first attenuator 34 supplies the attenuated pixel data b(i,j)/4 of the previous frame to the first subtracter 44. The first subtracter 44 subtracts the attenuated pixel data b(i,j)/4 of the previous frame from the first attenuator 34 from the delayed vertical interpolation pixel data b O k (i,j) from the sixth register 42 and supplies the resultant pixel data to the first adder 38. In result, the first interpolation circuit 10 produces the four vertical interpolation pixel data on the basis of the following equation (2): b.sub.O.sup.k (i,j)=b.sub.O.sup.k-1 (i,j)-b.sub.O (i,j)/4+b.sub.O (i,j+1)/4(2) Referring to FIG. 3, there is shown a detailed block diagram of the second interpolation circuit 22 in FIG. 1. As shown in this drawing, the second interpolation circuit 22 includes a third attenuator 46 for inputting the vertical interpolation pixel data b O k (i,j+1) of the subsequent pixel data from the first register 12 in FIG. 1 through a first input line 47, and a fourth attenuator 48 for inputting the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 in FIG. 1 through a second input line 49. The third attenuator 46 attenuates the vertical interpolation pixel data b O k (i,j+1) of the subsequent pixel data from the first register 12 in such a manner that it can have a 1/2 amplitude. Then, the third attenuator 46 supplies the attenuated vertical interpolation pixel data b O k (i,j+1)/2 of the subsequent pixel data to second and fourth adders 50 and 56. The fourth attenuator 48 attenuates the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 in such a manner that it can have a 1/2 amplitude. Then, the fourth attenuator 48 supplies the attenuated vertical interpolation pixel data b O k (i,j)/2 of the present pixel data to the second adder 50 and a third adder 54. The second adder 50 adds the attenuated vertical interpolation pixel data b O k (i,j+1)/2 and b O k (i,j)/2 from the third and fourth attenuators 46 and 48. As a result of the addition, the second adder 50 produces the horizontal interpolation pixel data b 2 k (i,j). The second interpolation circuit 22 further includes a fifth attenuator 52 for attenuating the horizontal interpolation pixel data {[b O k (i,j+1)+b O k (i,j)]/2=b 2 k (i,j)} from the second adder 50 in such a manner that it can have a 1/2 amplitude. The fifth attenuator 52 supplies the attenuated horizontal interpolation pixel data [b O k (i,j+1)+b O k (i,j)]/4 to the third and fourth adders 54 and 56. The third adder 54 adds the attenuated vertical interpolation pixel data b O k (i,j)/2 from the fourth attenuator 48 and the attenuated horizontal interpolation pixel data [b O k (i,j+1) +b O k (i,j)]/4 from the fifth attenuator 52. As a result of the addition, the third adder 54 produces the horizontal interpolation pixel data b 1 k (i,j). The fourth adder 56 adds the attenuated vertical interpolation pixel data b O k (i,j+1)/2 from the third attenuator 46 and the attenuated horizontal interpolation pixel data [b O k (i,j+1)+b O k (i,j)]/4 from the fifth attenuator 52. As a result of the addition, the fourth adder 56 produces the horizontal interpolation pixel data {b 3 k (i,j)=[3b O k (i,j+1)+b O k (i,j)]/4. The second interpolation circuit 22 further includes first to third output lines 51, 53 and 55 connected respectively to the third, second and fourth adders 54, 50 and 56. The second input line 49 transfers the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 as the horizontal interpolation pixel data to the first MAD detector 24 in FIG. 1. The first to third output lines 51, 53 and 55 transfer the horizontal interpolation pixel data b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) from the third, second and fourth adders 54, 50 and 56 to the second to fourth MAD detectors 26, 28 and 30 in FIG. 1, respectively. Referring to FIG. 4, there is shown a detailed block diagram of each of the first to fourth MAD detectors 24, 26, 28 and 30 in FIG. 1. As shown in this drawing, the MAD detector includes a second subtracter 58 for inputting the pixel data a(i,j) of the present frame and the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data through first and second input lines 15 and 59, respectively. The second subtracter 58 subtracts the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data from the pixel data a(i,j) of the present frame. As a result of the subtraction, the second subtracter 58 detects a difference between the pixel data a(i,j) of the present frame and the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data. Then, the second subtracter 58 supplies the detected difference to a seventh register 60. The first input line 15 is the same as the third input line 15 in FIG. 1. The second input line 59 is connected to the second input line 49, the first output line 51, the second output line 53 or the third output line 55 of the second interpolation circuit 22 in FIG. 1 to input the corresponding horizontal interpolation pixel data b O k (i,j), b 1 k (i,j), b 2 k (i,j) or b 3 k (i,j) therefrom. The seventh register 60 temporarily stores the inter-pixel difference from the second subtracter 58 and supplies the temporarily stored inter-pixel difference to an absolute value calculator 62. In result, the seventh register 60 acts to safely transfer the inter-pixel difference from the second subtracter 58 to the absolute value calculator 62. The absolute value calculator 62 obtains an absolute value of the inter-pixel difference from the seventh register 60 and supplies the obtained absolute value to an eighth register 64. The MAD detector further includes an accumulator 66 for inputting the absolute value of the inter-pixel difference from the eighth register 64. The accumulator 66 adds the absolute value of the inter-pixel difference from the eighth register 64 to an MAD from an output line 61 and transfers the resultant MAD to a ninth register 68. The ninth register 68 transfers the MAD from the accumulator 66 to the output line 61 through tenth to twelfth registers 70, 72 and 74. The ninth to twelfth registers 68, 70, 72 and 74 are connected between the accumulator 66 and the output line 61 to store the four MADs produced between the four vertical interpolation pixel data and the pixel data of the present frame, respectively. FIG. 5 is a table illustrating the interpolation pixel data from the first and second interpolation circuits 10 and 22 and the MADs from the first to fourth MAD detectors 24, 26, 28 and 30 with respect to the pixel data from the second input line 13 in FIG. 1. As mentioned above, the conventional motion vector extractor must perform the same operation four times to extract the motion vector with respect to one pixel, resulting in a significant reduction in the motion vector calculating speed. In order to enhance the motion vector calculating speed, the conventional motion vector extractor may perform the interpolation pixel data and MAD detections in a parallel manner. In this case, the circuit becomes very complex in construction. SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above problem, and it is an object of the present invention to provide an improved motion vector extractor which is capable of rapidly obtaining motion vectors and simplifying its circuit construction. In accordance with the present invention, the above and other objects can be accomplished by providing an improved motion vector extractor comprising first pixel delay means for delaying pixel data of the previous frame by a one pixel interval; second pixel delay means for delaying the pixel data of the previous frame by a horizontal line interval of a seek block; third pixel delay means for delaying the pixel data of the previous frame by a seek block horizontal line and one pixel interval; pixel interpolation means for combining the pixel data of the previous frame and the delayed pixel data of the previous frame from the first to third pixel delay means and producing at least one interpolation pixel data positioned between adjacent ones thereof, in accordance with the combined result; fourth pixel delay means for delaying pixel data of the present frame to produce rectangularly arranged pixel data of the present frame; a plurality of mean absolute difference detection means, each of the plurality of mean absolute difference detection means subtracting a corresponding one of the interpolation pixel data from the pixel interpolation means from a corresponding one of the rectangularly arranged pixel data of the present frame from the fourth pixel delay means to produce a mean absolute difference with respect to the corresponding pixel data of the present frame; and comparison means for comparing the mean absolute differences from the plurality of mean absolute difference detection means with one another and extracting a motion vector of a picture in accordance with the compared result. BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a block diagram of a conventional motion vector extractor; FIG. 2 is a detailed block diagram of a first interpolation circuit in FIG. 1; FIG. 3 is a detailed block diagram of a second interpolation circuit in FIG. 1; FIG. 4 is a detailed block diagram of each of the first to fourth MAD detectors in FIG. 1; FIG. 5 is a table illustrating output data from components in FIG. 1; FIG. 6 is a block diagram of an improved motion vector extractor in accordance with an embodiment of the present invention; FIG. 7 is a detailed block diagram of an interpolation circuit in FIG. 6; FIG. 8 is a detailed block diagram of each of the first to ninth MAD detectors in FIG. 6; and FIG. 9 is a table illustrating output data from components in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 6, there is shown a block diagram of an improved motion vector extractor in accordance with an embodiment of the present invention. As shown in this drawing, the improved motion vector extractor comprises first to fifth pixel delay elements 80, 82, 84, 86 and 88 connected in series to a first input line 81. In accordance with the preferred embodiment of the present invention, the improved motion vector extractor is constructed to extract a motion vector in the unit of 1/2 pixel. It is assumed here that the improved motion vector extractor processes the previous frame data of a seek block with 5×5 pixels with respect to the present frame data of a reference block with 3 ×3 pixels. The first pixel delay element 80 supplies pixel data b(i,j) of the previous frame from the first input line 81 to the second pixel delay element 82 and a first input line 83 of an interpolation circuit 90. The second pixel delay element 82 delays the pixel data b(i,j) of the previous frame from the first pixel delay element 80 by a one pixel interval and supplies the delayed pixel data b(i,j-1) of the previous frame to the third pixel delay element 84 and a second input line 85 of the interpolation circuit 90. The fourth pixel delay element 86 produces pixel data b(i-1,j) of the previous frame delayed by a horizontal line interval (i.e., five-pixel interval) of the seek block from the pixel data b(i,j) of the previous frame. Then, the fourth pixel delay element 86 supplies the produced pixel data b(i-1,j) of the previous frame to the fifth pixel delay element 88 and a third input line 87 of the interpolation circuit 90. The fifth pixel delay element 88 produces pixel data b(i-1,j-1) of the previous frame delayed by a seek block horizontal line and one pixel interval (i.e., six-pixel interval) from the pixel data b(i,j) of the previous frame. Then, the fifth pixel delay element 88 supplies the produced pixel data b(i-1,j-1) of the previous frame to a fourth input line 89 of the interpolation circuit 90. The third pixel delay element 84 acts to delay the delayed pixel data b(i,j-1) of the previous frame from the second pixel delay element 82 by a three-pixel interval and supply the delayed pixel data of the previous frame to the fourth pixel delay element 86. The interpolation circuit 90 inputs the pixel data b(i,j) of the previous frame from the first pixel delay element 80 and the delayed pixel data b(i,j-1), b(i-1,j) and b(i-1,j-1) of the previous frame from the second, fourth and fifth pixel delay elements 82, 86 and 88 through its first to fourth input lines 83, 85, 87 and 89, respectively. Then, the interpolation circuit 90 combines the inputted pixel data b(i,j), b(i,j-1), b(i-1,j) and b(i-1,j-1) of the previous frame. As a result of the combination, the interpolation circuit 90 produces four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j). The four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) are produced on the basis of the following equations (3) to (6): b.sub.0.sup.0 (i,j)=b(i,j) (3) b.sub.-1.sup.0 (i,j)=[b(i,j)+b(i-1,j)]/2 (4) b.sub.0.sup.-1 (i,j)=[b(i,j)+b(i,j-1)]/2 (5) b.sub.-1.sup.-1 (i,j)=[b(i,j)+b(i-1,j)+b(i,j-1)+b(i-1,j-1)]/4(6) The improved motion vector extractor further comprises first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116, each of which inputs a corresponding one of the four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) from the interpolation circuit 90, and a sixth pixel delay element 92 for inputting pixel data a(i,j) of the present frame from a second input line 91. The sixth pixel delay element 92 delays the pixel data a(i,j) of the present frame from the second input line 91 by the one pixel interval and supplies the delayed pixel data a(i,j-1) of the present frame to a seventh pixel delay element 94 and the fifth and sixth MAD detectors 108 and 110. The seventh pixel delay element 94 delays the delayed pixel data a(i,j-1) of the present frame from the sixth pixel delay element 92 again by the one pixel interval and thus produces pixel data a(i,j-2) of the present frame delayed by a two-pixel interval from the pixel data a(i,j) of the present frame. Then, the seventh pixel delay element 94 supplies the produced pixel data a(i,j-2) of the present frame to an eighth pixel delay element 96. The eighth pixel delay element 96 delays the delayed pixel data a(i,j-2) of the present frame from the seventh pixel delay element 94 again by the one pixel interval and thus produces pixel data a(i-1,j) of the present frame delayed by a horizontal line interval (i.e., three-pixel interval) of the reference block from the pixel data b(i,j) of the present frame. Then, the eighth pixel delay element 96 supplies the produced pixel data a(i,-1,j) of the present frame to the seventh and eighth MAD detectors 112 and 114 and a ninth pixel delay element 98. The ninth pixel delay element 98 delays the delayed pixel data a(i-1,j) of the present frame from the eighth pixel delay element 96 again by the one pixel interval and thus produces pixel data a(i-1,j-1) of the present frame delayed by a reference block horizontal line and one pixel interval (i.e., four-pixel interval) from the pixel data b(i,j) of the present frame. Then, the ninth pixel delay element 98 supplies the produced pixel data a(i-1,j-1) of the present frame to the ninth MAD detector 116. The first MAD detector 100 detects an MAD between the pixel data a(i,j) of the present frame from the second input line 91 and the interpolation pixel data b 0 0 (i,j) from a first output line 93 of the interpolation circuit 90. Then, the first MAD detector 100 supplies the detected MAD to a comparator 118. The second to fourth MAD detectors 102, 104 and 106 are connected respectively to second to fourth output lines 95, 97 and 99 of the interpolation circuit 90 to operate in a similar manner to the first MAD detector 100. Namely, each of the second to fourth MAD detectors 102, 104 and 106 detects an MAD between a corresponding one of the interpolation pixel data b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) from the interpolation circuit 90 and the pixel data a(i,j) of the present frame from the second input line 91. Then, the second to fourth MAD detectors 102, 104 and 106 supply the detected MADs to the comparator 118, respectively. The fifth to ninth MAD detectors 108, 110, 112, 114 and 116 are operated in a similar manner to the first to fourth MAD detectors 100, 102, 104 and 106 to detect respective MADs. Namely, the fifth MAD detector 108 detects an MAD between the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, interval, supplied from the sixth pixel delay element 92, and the interpolation pixel data b -1 0 (i,j) supplied from the second output line 95 of the interpolation circuit 90. The sixth MAD detector 110 detects an MAD between the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, supplied from the sixth pixel delay element 92, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90. The seventh MAD detector 112 detects an MAD between the pixel data a(i-1,j) of the present frame delayed by the horizontal line interval of the reference block, supplied from the eighth pixel delay element 96, and the interpolation pixel data b 0 -1 (i,j) supplied from the third output line 97 of the interpolation circuit 90. The eighth MAD detector 114 detects an MAD between the pixel data a(i-1,j) of the present frame delayed by the horizontal line interval of the reference block, supplied from the eighth pixel delay element 96, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90. Finally, the ninth MAD detector 116 detects an MAD between the pixel data a(i-1,j-1) of the present frame delayed by the reference block horizontal line and one pixel interval, supplied from the ninth pixel delay element 98, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90. The comparator 118 compares the nine MADs from the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 with one another. As a result of the comparison, the comparator 118 selects a minimum one of the nine MADs and outputs the selected MAD as a motion vector through an output line 101. Referring to FIG. 7, there is shown a detailed block diagram of the interpolation circuit 90 in FIG. 6. As shown in this drawing, the interpolation circuit 90 includes a first adder 120 for inputting the pixel data b(i,j) of the previous frame supplied through the first input line 83 from the first pixel delay element 80 in FIG. 6 and the pixel data b(i,j-1) of the previous frame delayed by the one pixel interval, supplied through the second input line 85 from the second pixel delay element 82 in FIG. 6. The first adder 120 adds the inputted two pixel data b(i,j) and b(i,j-1) and supplies the resultant pixel data [b(i,j)+b(i,j-1)] to a first attenuator 128. The first attenuator 128 attenuates the pixel data [b(i,j)+b(i,j-1)] from the first adder 120 in such a manner that it can have a 1/2 amplitude. Then, the first attenuator 128 supplies the attenuated pixel data [b(i,j)+b(i,j-1)]/2 as the interpolation pixel data b -1 0 (i,j) to the second and fifth MAD detectors 102 and 108 in FIG. 6 through the second output line 95. The interpolation circuit 90 further includes a second adder 122 for inputting the pixel data b(i,j) of the previous frame supplied through the first input line 83 from the first pixel delay element 80 in FIG. 6 and the pixel data b(i-1,j) of the previous frame delayed by the one horizontal line interval (i.e., three-pixel interval), supplied through the third input line 87 from the fourth pixel delay element 86 in FIG. 6. The second adder 122 adds the inputted two pixel data b(i,j) and b(i-1,j) and supplies the resultant pixel data [b(i,j)+b(i-1,j)] to a second attenuator 130. The second attenuator 130 attenuates the pixel data [b(i,j)+b(i-1,j)] from the second adder 122 in such a manner that it can have a 1/2 amplitude. Then, the second attenuator 130 supplies the attenuated pixel data [b(i,j)+b(i-1,j)]/2 as the interpolation pixel data b 0 -1 (i,j) to the third and seventh MAD detectors 104 and 112 in FIG. 6 through the third output line 97. The interpolation circuit 90 further includes a third adder 124 for inputting the pixel data b(i-1,j) of the previous frame delayed by the one block horizontal line interval, supplied through the third input line 87 from the fourth pixel delay element 86 in FIG. 6, and the pixel data b(i-1,j-1) of the previous frame delayed by the one block horizontal line and one pixel interval (i.e., four-pixel interval), supplied through the fourth input line 89 from the fifth pixel delay element 88 in FIG. 6. The third adder 124 adds the inputted two pixel data b(i-1,j) and b(i-1,j-1) and supplies the resultant pixel data [b(i-1,j)+b(i-1,j-1)] to a fourth adder 126 which also inputs the pixel data [b(i,j)+b(i,j-1)] from the first adder 120. The fourth adder 126 adds the pixel data [b(i,j)+b(i,j-1)] from the first adder 120 to the pixel data [b(i-1,j)+b(i-1,j-1)] from the third adder 124 and supplies the resultant pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)] to a third attenuator 132. The third attenuator 132 attenuates the pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)] from the fourth adder 126 in such a manner that it can have a 1/2 amplitude. Then, the third attenuator 132 supplies the attenuated pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)]/2 as the interpolation pixel data b -1 -1 (i,j) to the fourth, sixth, eighth and ninth MAD detectors 106, 110, 114 and 116 in FIG. 6 through the fourth output line 99. Referring to FIG. 8, there is shown a detailed block diagram of each of the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 in FIG. 6. As shown in this drawing, the MAD detector includes a subtracter 134 for inputting the interpolation pixel data b l k (i,j) from a first input line 135 and the pixel data a(i,j) of the present frame from a second input line 137. The first input line 135 is connected to the first, second, third or fourth output line 93, 95, 97 or 99 of the interpolation circuit 90 in FIGS. 6 and 7 to input the corresponding interpolation pixel data b l k (i,j) (i.e., b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) or b -1 -1 (i,j)) therefrom. The second input line 137 is connected to the second input line 91, an output line of the sixth pixel delay element 92, an output line of the eighth pixel delay element 96 or an output line of the ninth pixel delay element 98 in FIG. 6 to input therefrom the pixel data a(i,j) of the present frame, the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, the pixel data a(i-1,j) of the present frame delayed by the reference block horizontal line interval (i.e., three-pixel interval) or the pixel data a(i-1,j-1) of the present frame delayed by the reference block horizontal line and one pixel interval (i.e., four-pixel interval). For the convenience of the description, it is here assumed that the second input line 137 inputs the pixel data a(i,j) of the present frame from the second input line 91 in FIG. 6, not delayed. The subtracter 134 subtracts the interpolation pixel data b 1 k (i,j) from the pixel data a(i,j) of the present frame. As a result of the subtraction, the subtracter 134 detects a difference between the pixel data a(i,j) of the present frame and the interpolation pixel data b 1 k (i,j). Then, the subtracter 134 supplies the detected difference to a first register 136. The first register 136 temporarily stores the inter-pixel difference from the subtracter 134 and supplies the temporarily stored inter-pixel difference to an absolute value calculator 138. In result, the first register 136 acts to safely transfer the inter-pixel difference from the subtracter 134 to the absolute value calculator 138. The absolute value calculator 138 obtains an absolute value of the inter-pixel difference from the first register 136 and supplies the obtained absolute value to a second register 140. The MAD detector further includes an accumulator 142 for inputting the absolute value of the inter-pixel difference from the second register 140. The accumulator 142 adds the absolute value of the inter-pixel difference from the second register 140 to the present MAD fed back from its output line and transfers the resultant MAD to a third register 144. The third register 144 transfers the MAD from the accumulator 142 to the comparator 118 in FIG. 6 through an output line 139. FIG. 9 is a table illustrating the output data from the interpolation circuit 90 and the MADs from the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 with respect to the 5×5 pixel data from the first input line 81 in FIG. 6. As seen from this drawing, the improved motion vector extractor performs the calculating operation once to extract the motion vector. As apparent from the above description, the improved motion vector extractor of the present invention has the effect of shortening the motion vector extracting time. Also, the improved motion vector extractor of the present invention can produce the interpolation pixel data without resorting to parallel MAD processing as discussed in the Description of the Prior Art. Therefore, the circuit can be simplified in construction. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
An improved motion vector extractor comprising a first pixel delay element for delaying pixel data of the previous frame by a one pixel interval, a second pixel delay element for delaying the pixel data of the previous frame by a horizontal line interval of a seek block, a third pixel delay element for delaying the pixel data of the previous frame by a seek block horizontal line and one pixel interval, an interpolation circuit for combining the pixel data of the previous frame and the delayed pixel data of the previous frame from the first to third pixel delay elements to produce at least one interpolation pixel data positioned between adjacent ones thereof, a fourth pixel delay element for delaying pixel data of the present frame to produce rectangularly arranged pixel data of the present frame, a plurality of MAD detectors, each of the plurality of MAD detectors subtracting a corresponding one of the interpolation pixel data from the interpolation circuit from a corresponding one of the rectangularly arranged pixel data of the present frame from the fourth pixel delay element to produce an MAD with respect to the corresponding pixel data of the present frame, and a comparator for comparing the MADs from the plurality of MAD detectors with one another and extracting a motion vector in accordance with the compared result.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates in general to an apparatus for compressing video data to transmit moving picture data in real time through a transmission medium with a limited band width, and more particularly to an improved motion vector extractor which is capable of rapidly extracting motion vectors from the moving picture data to be transmitted and simplifying its circuit construction.", "Description of the Prior Art Recently, digital video transmission systems have utilized a data compression method to transmit moving picture data in real time through a transmission channel with a limited band width to digital video reception systems such as a digital video phone, a digital video conversation system, a digital television and a high definition television.", "The data compression method is adapted to compress the moving picture data by removing time and spatial redundancies of the moving picture data.", "The time redundancy removing methods include motion vector estimation and compensation methods for transmitting only motion vectors regarding a moving object or a part of the moving object to have the actual video data transmission effect.", "This results from the moving picture data having a series of frames corresponding to the moving object.", "The motion vector estimation method is generally classified into a recursive method and a matching method.", "In the matching method, there is widely used a block matching algorithm for matching the moving picture data in the unit of block to estimate the motion vectors from the moving picture data.", "The ISO/IEC JTC1/SC29/WG11 recommendation proposed by the moving picture expert group (MPEG) specifies a block matching algorithm which finds the motion vectors in the unit of macro block including 16×16 pixels.", "This recommendation also suggests that the motion vectors be estimated in the unit of 1/2 pixel to enhance the accuracy thereof.", "On the basis of the above recommendation, the digital video transmission systems comprise a motion vector extractor for extracting a motion vector in a pixel unit smaller than an integer, such as 1/4 pixel or 1/2 pixel, to secure the accuracy of the video data to be transmitted.", "Such a conventional motion vector extractor produces interpolation pixel data using desired integer pixel data and integer pixel data adjacent up, down, to the left and to the right of the desired integer pixel data.", "The conventional motion vector extractor calculates a mean absolute difference (referred to hereinafter as "MAD") between the desired integer pixel data and each of the produced interpolation pixel data.", "Then, the conventional motion vector extractor compares the calculated MADs with one another and calculates the motion vector in accordance with the compared result.", "In the case of estimating the motion vector in the unit of 1/4 pixel, the conventional motion vector extractor must calculate 16 of 49 interpolation pixel data, adjacent to one side of the desired integer pixel data, and the corresponding MADs.", "In the case of estimating the motion vector in the unit of 1/2 pixel, the conventional motion vector extractor must calculate 4 of 9 interpolation pixel data, adjacent to one side of the desired integer pixel data, and the corresponding MADs.", "However, the above-mentioned conventional motion vector extractor has a disadvantage in that it sequentially calculates one by one the interpolation pixel data related to the desired integer pixel data, resulting in much time being required in calculating the motion vector.", "Further, the above-mentioned conventional motion vector extractor has another disadvantage in that it must have a complex circuit construction to enhance the motion vector calculating time.", "The problem with the above-mentioned conventional motion vector extractor will hereinafter be described in detail with reference to FIGS. 1 to 5.", "Referring to FIG. 1, there is shown a block diagram of the conventional motion vector extractor for extracting the motion vector in the unit of 1/4 pixel.", "As shown in this drawing, the conventional motion vector extractor comprises a first interpolation circuit 10 for inputting pixel data b(i,j) of the previous frame (referred to hereinafter as "present pixel data") and pixel data b(i+1,j) of the subsequent block line of the pixel data b(i,j) (referred to hereinafter as "subsequent line pixel data") from first and second input lines 11 and 13, respectively.", "Here, "i"", "and "j"", "designate vertical and horizontal coordinates of the pixel data, respectively.", "The first interpolation circuit 10 obtains four vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) with respect to the pixel data b(i,j) of the previous frame using the pixel data b(i,j) of the previous frame and the subsequent line pixel data b(i+1,j).", "Then, the first interpolation circuit 10 sequentially supplies the obtained vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) to a first register 12.", "The first register 12 sequentially supplies the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) from the first interpolation circuit 10 to a second interpolation circuit 22 and a second register 14.", "The second to fifth registers 14, 16, 18 and 20 are connected in series to the first register 12 to delay the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) from the first register 12 by a one pixel interval, respectively.", "As a result, the fifth register 20 sequentially supplies the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) regarding the present pixel data to the second interpolation circuit 22, whereas the first register 12 sequentially supplies vertical interpolation pixel data b 0 0 (i,j+1), b 0 1 (i,j+1), b 0 2 (i,j+1) and b 0 3 (i,j+1) regarding the subsequent pixel data to the second interpolation circuit 22.", "The second interpolation circuit 22 combines the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j) regarding the present pixel data, supplied from the fifth register 20, and the vertical interpolation pixel data b 0 0 (i,j+1), b 0 1 (i,j+1), b 0 2 (i,j+1) and b 0 3 (i,j+1) regarding the subsequent pixel data, supplied from the first register 12.", "As a result of the combination, the second interpolation circuit 22 obtains four horizontal interpolation pixel data b 0 k (i,j), b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) with respect to each of the vertical interpolation pixel data b 0 0 (i,j), b 0 1 (i,j), b 0 2 (i,j) and b 0 3 (i,j).", "The conventional motion vector extractor further comprises first to fourth MAD detectors 24, 26, 28 and 30 for inputting pixel data a (i,j) of the present frame from a third input line 15.", "The first MAD detector 24 sequentially obtains four MADs in the vertical direction on the basis of the pixel data a (i,j) of the present frame from the third input line 15 and the horizontal interpolation pixel data b 0 k (i,j) from the second interpolation circuit 22.", "Then, the first MAD detector 24 sequentially supplies the obtained four MADs to a comparator 32.", "Similarly, each of the second to fourth MAD detectors 26, 28 and 30 obtains four MADs in the vertical direction on the basis of the pixel data a (i,j) of the present frame from the third input line 15 and a corresponding one of the horizontal interpolation pixel data b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) from the second interpolation circuit 22 and then supplies the obtained four MADs to the comparator 32.", "The comparator 32 compares the MADs from the first to fourth MAD detectors 24, 26, 28 and 30 with one another and detects the motion vector in accordance with the compared result.", "The second interpolation circuit 22, the first to fourth MAD detectors 24, 26, 28 and 30 and the comparator 32 are operated four times to extract the motion vector regarding one pixel at output line 17.", "The first and second interpolation circuits 10 and 22 are operated four times to produce 16 interpolation pixel data on the basis of the following equation (1): b.sub[.", "].1.", "sup.", "k (i,j)=(4-l)/4{(4-k)b(i,j)/4+kb(i+1,j)/4}+l/4{(4-k)b(i,j+1)/4+kb(i+1,j+1)/4}(1) Referring to FIG. 2, there is shown a detailed block diagram of the first interpolation circuit 10 in FIG. 1. As shown in this drawing, the first interpolation circuit 10 includes a first attenuator 34 for inputting the pixel data b(i,j) of the previous frame from the first input line 11, and a second attenuator 36 for inputting the subsequent line pixel data b(i+1,j) from the second input line 13.", "The second attenuator 36 attenuates the subsequent line pixel data b(i+1,j) from the second input line 13 in such a manner that it can have a 1/4 amplitude.", "Then, the second attenuator 36 supplies the attenuated subsequent line pixel data b(i+1,j)/4 to a first adder 38.", "The first adder 38 adds pixel data from a first subtracter 44 to the attenuated subsequent line pixel data b(i+1,j)/4 from the second attenuator 36.", "As a result of the addition, the first adder 38 obtains the vertical interpolation pixel data b 0 k (i,j).", "The first adder 38 then supplies the obtained vertical interpolation pixel data b 0 k (i,j) to a multiplexer 40.", "The multiplexer 40 selectively transfers the vertical interpolation pixel data b 0 k (i,j) from the first adder 38 and the pixel data b(i,j) of the previous frame from the first input line 11 through an output line 35 to the first register 12 in FIG. 1. Namely, at the initial state, the multiplexer 40 transfers the pixel data b(i,j) of the previous frame from the first input line 11 as the vertical interpolation pixel data b 0 k (i,j) through the output line 35 to the first register 12.", "At the normal state, the multiplexer 40 transfers the vertical interpolation pixel data b 0 k (i,j) from the first adder 38 through the output line 35 to the first register 12.", "The first interpolation circuit 10 further includes a sixth register 42 for inputting the vertical interpolation pixel data b O k (i,j) selected by the multiplexer 40 through the output line 35.", "The sixth register 42 delays the vertical interpolation pixel data b O k (i,j) from the multiplexer 40 for a predetermined time period and supplies the delayed vertical interpolation pixel data b O k (i,j) to the first subtracter 44.", "The first attenuator 34 attenuates the pixel data b(i,j) of the previous frame from the first input line 11 in such a manner that it can have a 1/4 amplitude.", "Then, the first attenuator 34 supplies the attenuated pixel data b(i,j)/4 of the previous frame to the first subtracter 44.", "The first subtracter 44 subtracts the attenuated pixel data b(i,j)/4 of the previous frame from the first attenuator 34 from the delayed vertical interpolation pixel data b O k (i,j) from the sixth register 42 and supplies the resultant pixel data to the first adder 38.", "In result, the first interpolation circuit 10 produces the four vertical interpolation pixel data on the basis of the following equation (2): b.sub.O.sup.", "k (i,j)=b.", "sub.O.sup.", "k-1 (i,j)-b.", "sub.", "O (i,j)/4+b.", "sub.", "O (i,j+1)/4(2) Referring to FIG. 3, there is shown a detailed block diagram of the second interpolation circuit 22 in FIG. 1. As shown in this drawing, the second interpolation circuit 22 includes a third attenuator 46 for inputting the vertical interpolation pixel data b O k (i,j+1) of the subsequent pixel data from the first register 12 in FIG. 1 through a first input line 47, and a fourth attenuator 48 for inputting the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 in FIG. 1 through a second input line 49.", "The third attenuator 46 attenuates the vertical interpolation pixel data b O k (i,j+1) of the subsequent pixel data from the first register 12 in such a manner that it can have a 1/2 amplitude.", "Then, the third attenuator 46 supplies the attenuated vertical interpolation pixel data b O k (i,j+1)/2 of the subsequent pixel data to second and fourth adders 50 and 56.", "The fourth attenuator 48 attenuates the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 in such a manner that it can have a 1/2 amplitude.", "Then, the fourth attenuator 48 supplies the attenuated vertical interpolation pixel data b O k (i,j)/2 of the present pixel data to the second adder 50 and a third adder 54.", "The second adder 50 adds the attenuated vertical interpolation pixel data b O k (i,j+1)/2 and b O k (i,j)/2 from the third and fourth attenuators 46 and 48.", "As a result of the addition, the second adder 50 produces the horizontal interpolation pixel data b 2 k (i,j).", "The second interpolation circuit 22 further includes a fifth attenuator 52 for attenuating the horizontal interpolation pixel data {[b O k (i,j+1)+b O k (i,j)]/2=b 2 k (i,j)} from the second adder 50 in such a manner that it can have a 1/2 amplitude.", "The fifth attenuator 52 supplies the attenuated horizontal interpolation pixel data [b O k (i,j+1)+b O k (i,j)]/4 to the third and fourth adders 54 and 56.", "The third adder 54 adds the attenuated vertical interpolation pixel data b O k (i,j)/2 from the fourth attenuator 48 and the attenuated horizontal interpolation pixel data [b O k (i,j+1) +b O k (i,j)]/4 from the fifth attenuator 52.", "As a result of the addition, the third adder 54 produces the horizontal interpolation pixel data b 1 k (i,j).", "The fourth adder 56 adds the attenuated vertical interpolation pixel data b O k (i,j+1)/2 from the third attenuator 46 and the attenuated horizontal interpolation pixel data [b O k (i,j+1)+b O k (i,j)]/4 from the fifth attenuator 52.", "As a result of the addition, the fourth adder 56 produces the horizontal interpolation pixel data {b 3 k (i,j)=[3b O k (i,j+1)+b O k (i,j)]/4.", "The second interpolation circuit 22 further includes first to third output lines 51, 53 and 55 connected respectively to the third, second and fourth adders 54, 50 and 56.", "The second input line 49 transfers the vertical interpolation pixel data b O k (i,j) of the present pixel data from the fifth register 20 as the horizontal interpolation pixel data to the first MAD detector 24 in FIG. 1. The first to third output lines 51, 53 and 55 transfer the horizontal interpolation pixel data b 1 k (i,j), b 2 k (i,j) and b 3 k (i,j) from the third, second and fourth adders 54, 50 and 56 to the second to fourth MAD detectors 26, 28 and 30 in FIG. 1, respectively.", "Referring to FIG. 4, there is shown a detailed block diagram of each of the first to fourth MAD detectors 24, 26, 28 and 30 in FIG. 1. As shown in this drawing, the MAD detector includes a second subtracter 58 for inputting the pixel data a(i,j) of the present frame and the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data through first and second input lines 15 and 59, respectively.", "The second subtracter 58 subtracts the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data from the pixel data a(i,j) of the present frame.", "As a result of the subtraction, the second subtracter 58 detects a difference between the pixel data a(i,j) of the present frame and the horizontal interpolation pixel data b 1 k (i,j) regarding the present pixel data.", "Then, the second subtracter 58 supplies the detected difference to a seventh register 60.", "The first input line 15 is the same as the third input line 15 in FIG. 1. The second input line 59 is connected to the second input line 49, the first output line 51, the second output line 53 or the third output line 55 of the second interpolation circuit 22 in FIG. 1 to input the corresponding horizontal interpolation pixel data b O k (i,j), b 1 k (i,j), b 2 k (i,j) or b 3 k (i,j) therefrom.", "The seventh register 60 temporarily stores the inter-pixel difference from the second subtracter 58 and supplies the temporarily stored inter-pixel difference to an absolute value calculator 62.", "In result, the seventh register 60 acts to safely transfer the inter-pixel difference from the second subtracter 58 to the absolute value calculator 62.", "The absolute value calculator 62 obtains an absolute value of the inter-pixel difference from the seventh register 60 and supplies the obtained absolute value to an eighth register 64.", "The MAD detector further includes an accumulator 66 for inputting the absolute value of the inter-pixel difference from the eighth register 64.", "The accumulator 66 adds the absolute value of the inter-pixel difference from the eighth register 64 to an MAD from an output line 61 and transfers the resultant MAD to a ninth register 68.", "The ninth register 68 transfers the MAD from the accumulator 66 to the output line 61 through tenth to twelfth registers 70, 72 and 74.", "The ninth to twelfth registers 68, 70, 72 and 74 are connected between the accumulator 66 and the output line 61 to store the four MADs produced between the four vertical interpolation pixel data and the pixel data of the present frame, respectively.", "FIG. 5 is a table illustrating the interpolation pixel data from the first and second interpolation circuits 10 and 22 and the MADs from the first to fourth MAD detectors 24, 26, 28 and 30 with respect to the pixel data from the second input line 13 in FIG. 1. As mentioned above, the conventional motion vector extractor must perform the same operation four times to extract the motion vector with respect to one pixel, resulting in a significant reduction in the motion vector calculating speed.", "In order to enhance the motion vector calculating speed, the conventional motion vector extractor may perform the interpolation pixel data and MAD detections in a parallel manner.", "In this case, the circuit becomes very complex in construction.", "SUMMARY OF THE INVENTION Therefore, the present invention has been made in view of the above problem, and it is an object of the present invention to provide an improved motion vector extractor which is capable of rapidly obtaining motion vectors and simplifying its circuit construction.", "In accordance with the present invention, the above and other objects can be accomplished by providing an improved motion vector extractor comprising first pixel delay means for delaying pixel data of the previous frame by a one pixel interval;", "second pixel delay means for delaying the pixel data of the previous frame by a horizontal line interval of a seek block;", "third pixel delay means for delaying the pixel data of the previous frame by a seek block horizontal line and one pixel interval;", "pixel interpolation means for combining the pixel data of the previous frame and the delayed pixel data of the previous frame from the first to third pixel delay means and producing at least one interpolation pixel data positioned between adjacent ones thereof, in accordance with the combined result;", "fourth pixel delay means for delaying pixel data of the present frame to produce rectangularly arranged pixel data of the present frame;", "a plurality of mean absolute difference detection means, each of the plurality of mean absolute difference detection means subtracting a corresponding one of the interpolation pixel data from the pixel interpolation means from a corresponding one of the rectangularly arranged pixel data of the present frame from the fourth pixel delay means to produce a mean absolute difference with respect to the corresponding pixel data of the present frame;", "and comparison means for comparing the mean absolute differences from the plurality of mean absolute difference detection means with one another and extracting a motion vector of a picture in accordance with the compared result.", "BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a block diagram of a conventional motion vector extractor;", "FIG. 2 is a detailed block diagram of a first interpolation circuit in FIG. 1;", "FIG. 3 is a detailed block diagram of a second interpolation circuit in FIG. 1;", "FIG. 4 is a detailed block diagram of each of the first to fourth MAD detectors in FIG. 1;", "FIG. 5 is a table illustrating output data from components in FIG. 1;", "FIG. 6 is a block diagram of an improved motion vector extractor in accordance with an embodiment of the present invention;", "FIG. 7 is a detailed block diagram of an interpolation circuit in FIG. 6;", "FIG. 8 is a detailed block diagram of each of the first to ninth MAD detectors in FIG. 6;", "and FIG. 9 is a table illustrating output data from components in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 6, there is shown a block diagram of an improved motion vector extractor in accordance with an embodiment of the present invention.", "As shown in this drawing, the improved motion vector extractor comprises first to fifth pixel delay elements 80, 82, 84, 86 and 88 connected in series to a first input line 81.", "In accordance with the preferred embodiment of the present invention, the improved motion vector extractor is constructed to extract a motion vector in the unit of 1/2 pixel.", "It is assumed here that the improved motion vector extractor processes the previous frame data of a seek block with 5×5 pixels with respect to the present frame data of a reference block with 3 ×3 pixels.", "The first pixel delay element 80 supplies pixel data b(i,j) of the previous frame from the first input line 81 to the second pixel delay element 82 and a first input line 83 of an interpolation circuit 90.", "The second pixel delay element 82 delays the pixel data b(i,j) of the previous frame from the first pixel delay element 80 by a one pixel interval and supplies the delayed pixel data b(i,j-1) of the previous frame to the third pixel delay element 84 and a second input line 85 of the interpolation circuit 90.", "The fourth pixel delay element 86 produces pixel data b(i-1,j) of the previous frame delayed by a horizontal line interval (i.e., five-pixel interval) of the seek block from the pixel data b(i,j) of the previous frame.", "Then, the fourth pixel delay element 86 supplies the produced pixel data b(i-1,j) of the previous frame to the fifth pixel delay element 88 and a third input line 87 of the interpolation circuit 90.", "The fifth pixel delay element 88 produces pixel data b(i-1,j-1) of the previous frame delayed by a seek block horizontal line and one pixel interval (i.e., six-pixel interval) from the pixel data b(i,j) of the previous frame.", "Then, the fifth pixel delay element 88 supplies the produced pixel data b(i-1,j-1) of the previous frame to a fourth input line 89 of the interpolation circuit 90.", "The third pixel delay element 84 acts to delay the delayed pixel data b(i,j-1) of the previous frame from the second pixel delay element 82 by a three-pixel interval and supply the delayed pixel data of the previous frame to the fourth pixel delay element 86.", "The interpolation circuit 90 inputs the pixel data b(i,j) of the previous frame from the first pixel delay element 80 and the delayed pixel data b(i,j-1), b(i-1,j) and b(i-1,j-1) of the previous frame from the second, fourth and fifth pixel delay elements 82, 86 and 88 through its first to fourth input lines 83, 85, 87 and 89, respectively.", "Then, the interpolation circuit 90 combines the inputted pixel data b(i,j), b(i,j-1), b(i-1,j) and b(i-1,j-1) of the previous frame.", "As a result of the combination, the interpolation circuit 90 produces four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j).", "The four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) are produced on the basis of the following equations (3) to (6): b.sub[.", "].0.", "sup[.", "].0 (i,j)=b(i,j) (3) b.sub.", "-1.", "sup[.", "].0 (i,j)=[b(i,j)+b(i-1,j)]/2 (4) b.sub[.", "].0.", "sup.", "-1 (i,j)=[b(i,j)+b(i,j-1)]/2 (5) b.sub.", "-1.", "sup.", "-1 (i,j)=[b(i,j)+b(i-1,j)+b(i,j-1)+b(i-1,j-1)]/4(6) The improved motion vector extractor further comprises first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116, each of which inputs a corresponding one of the four interpolation pixel data b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) from the interpolation circuit 90, and a sixth pixel delay element 92 for inputting pixel data a(i,j) of the present frame from a second input line 91.", "The sixth pixel delay element 92 delays the pixel data a(i,j) of the present frame from the second input line 91 by the one pixel interval and supplies the delayed pixel data a(i,j-1) of the present frame to a seventh pixel delay element 94 and the fifth and sixth MAD detectors 108 and 110.", "The seventh pixel delay element 94 delays the delayed pixel data a(i,j-1) of the present frame from the sixth pixel delay element 92 again by the one pixel interval and thus produces pixel data a(i,j-2) of the present frame delayed by a two-pixel interval from the pixel data a(i,j) of the present frame.", "Then, the seventh pixel delay element 94 supplies the produced pixel data a(i,j-2) of the present frame to an eighth pixel delay element 96.", "The eighth pixel delay element 96 delays the delayed pixel data a(i,j-2) of the present frame from the seventh pixel delay element 94 again by the one pixel interval and thus produces pixel data a(i-1,j) of the present frame delayed by a horizontal line interval (i.e., three-pixel interval) of the reference block from the pixel data b(i,j) of the present frame.", "Then, the eighth pixel delay element 96 supplies the produced pixel data a(i,-1,j) of the present frame to the seventh and eighth MAD detectors 112 and 114 and a ninth pixel delay element 98.", "The ninth pixel delay element 98 delays the delayed pixel data a(i-1,j) of the present frame from the eighth pixel delay element 96 again by the one pixel interval and thus produces pixel data a(i-1,j-1) of the present frame delayed by a reference block horizontal line and one pixel interval (i.e., four-pixel interval) from the pixel data b(i,j) of the present frame.", "Then, the ninth pixel delay element 98 supplies the produced pixel data a(i-1,j-1) of the present frame to the ninth MAD detector 116.", "The first MAD detector 100 detects an MAD between the pixel data a(i,j) of the present frame from the second input line 91 and the interpolation pixel data b 0 0 (i,j) from a first output line 93 of the interpolation circuit 90.", "Then, the first MAD detector 100 supplies the detected MAD to a comparator 118.", "The second to fourth MAD detectors 102, 104 and 106 are connected respectively to second to fourth output lines 95, 97 and 99 of the interpolation circuit 90 to operate in a similar manner to the first MAD detector 100.", "Namely, each of the second to fourth MAD detectors 102, 104 and 106 detects an MAD between a corresponding one of the interpolation pixel data b -1 0 (i,j), b 0 -1 (i,j) and b -1 -1 (i,j) from the interpolation circuit 90 and the pixel data a(i,j) of the present frame from the second input line 91.", "Then, the second to fourth MAD detectors 102, 104 and 106 supply the detected MADs to the comparator 118, respectively.", "The fifth to ninth MAD detectors 108, 110, 112, 114 and 116 are operated in a similar manner to the first to fourth MAD detectors 100, 102, 104 and 106 to detect respective MADs.", "Namely, the fifth MAD detector 108 detects an MAD between the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, interval, supplied from the sixth pixel delay element 92, and the interpolation pixel data b -1 0 (i,j) supplied from the second output line 95 of the interpolation circuit 90.", "The sixth MAD detector 110 detects an MAD between the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, supplied from the sixth pixel delay element 92, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90.", "The seventh MAD detector 112 detects an MAD between the pixel data a(i-1,j) of the present frame delayed by the horizontal line interval of the reference block, supplied from the eighth pixel delay element 96, and the interpolation pixel data b 0 -1 (i,j) supplied from the third output line 97 of the interpolation circuit 90.", "The eighth MAD detector 114 detects an MAD between the pixel data a(i-1,j) of the present frame delayed by the horizontal line interval of the reference block, supplied from the eighth pixel delay element 96, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90.", "Finally, the ninth MAD detector 116 detects an MAD between the pixel data a(i-1,j-1) of the present frame delayed by the reference block horizontal line and one pixel interval, supplied from the ninth pixel delay element 98, and the interpolation pixel data b -1 -1 (i,j) supplied from the fourth output line 99 of the interpolation circuit 90.", "The comparator 118 compares the nine MADs from the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 with one another.", "As a result of the comparison, the comparator 118 selects a minimum one of the nine MADs and outputs the selected MAD as a motion vector through an output line 101.", "Referring to FIG. 7, there is shown a detailed block diagram of the interpolation circuit 90 in FIG. 6. As shown in this drawing, the interpolation circuit 90 includes a first adder 120 for inputting the pixel data b(i,j) of the previous frame supplied through the first input line 83 from the first pixel delay element 80 in FIG. 6 and the pixel data b(i,j-1) of the previous frame delayed by the one pixel interval, supplied through the second input line 85 from the second pixel delay element 82 in FIG. 6. The first adder 120 adds the inputted two pixel data b(i,j) and b(i,j-1) and supplies the resultant pixel data [b(i,j)+b(i,j-1)] to a first attenuator 128.", "The first attenuator 128 attenuates the pixel data [b(i,j)+b(i,j-1)] from the first adder 120 in such a manner that it can have a 1/2 amplitude.", "Then, the first attenuator 128 supplies the attenuated pixel data [b(i,j)+b(i,j-1)]/2 as the interpolation pixel data b -1 0 (i,j) to the second and fifth MAD detectors 102 and 108 in FIG. 6 through the second output line 95.", "The interpolation circuit 90 further includes a second adder 122 for inputting the pixel data b(i,j) of the previous frame supplied through the first input line 83 from the first pixel delay element 80 in FIG. 6 and the pixel data b(i-1,j) of the previous frame delayed by the one horizontal line interval (i.e., three-pixel interval), supplied through the third input line 87 from the fourth pixel delay element 86 in FIG. 6. The second adder 122 adds the inputted two pixel data b(i,j) and b(i-1,j) and supplies the resultant pixel data [b(i,j)+b(i-1,j)] to a second attenuator 130.", "The second attenuator 130 attenuates the pixel data [b(i,j)+b(i-1,j)] from the second adder 122 in such a manner that it can have a 1/2 amplitude.", "Then, the second attenuator 130 supplies the attenuated pixel data [b(i,j)+b(i-1,j)]/2 as the interpolation pixel data b 0 -1 (i,j) to the third and seventh MAD detectors 104 and 112 in FIG. 6 through the third output line 97.", "The interpolation circuit 90 further includes a third adder 124 for inputting the pixel data b(i-1,j) of the previous frame delayed by the one block horizontal line interval, supplied through the third input line 87 from the fourth pixel delay element 86 in FIG. 6, and the pixel data b(i-1,j-1) of the previous frame delayed by the one block horizontal line and one pixel interval (i.e., four-pixel interval), supplied through the fourth input line 89 from the fifth pixel delay element 88 in FIG. 6. The third adder 124 adds the inputted two pixel data b(i-1,j) and b(i-1,j-1) and supplies the resultant pixel data [b(i-1,j)+b(i-1,j-1)] to a fourth adder 126 which also inputs the pixel data [b(i,j)+b(i,j-1)] from the first adder 120.", "The fourth adder 126 adds the pixel data [b(i,j)+b(i,j-1)] from the first adder 120 to the pixel data [b(i-1,j)+b(i-1,j-1)] from the third adder 124 and supplies the resultant pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)] to a third attenuator 132.", "The third attenuator 132 attenuates the pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)] from the fourth adder 126 in such a manner that it can have a 1/2 amplitude.", "Then, the third attenuator 132 supplies the attenuated pixel data [b(i-1,j)+b(i-1,j-1)+b(i,j)+b(i,j-1)]/2 as the interpolation pixel data b -1 -1 (i,j) to the fourth, sixth, eighth and ninth MAD detectors 106, 110, 114 and 116 in FIG. 6 through the fourth output line 99.", "Referring to FIG. 8, there is shown a detailed block diagram of each of the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 in FIG. 6. As shown in this drawing, the MAD detector includes a subtracter 134 for inputting the interpolation pixel data b l k (i,j) from a first input line 135 and the pixel data a(i,j) of the present frame from a second input line 137.", "The first input line 135 is connected to the first, second, third or fourth output line 93, 95, 97 or 99 of the interpolation circuit 90 in FIGS. 6 and 7 to input the corresponding interpolation pixel data b l k (i,j) (i.e., b 0 0 (i,j), b -1 0 (i,j), b 0 -1 (i,j) or b -1 -1 (i,j)) therefrom.", "The second input line 137 is connected to the second input line 91, an output line of the sixth pixel delay element 92, an output line of the eighth pixel delay element 96 or an output line of the ninth pixel delay element 98 in FIG. 6 to input therefrom the pixel data a(i,j) of the present frame, the pixel data a(i,j-1) of the present frame delayed by the one pixel interval, the pixel data a(i-1,j) of the present frame delayed by the reference block horizontal line interval (i.e., three-pixel interval) or the pixel data a(i-1,j-1) of the present frame delayed by the reference block horizontal line and one pixel interval (i.e., four-pixel interval).", "For the convenience of the description, it is here assumed that the second input line 137 inputs the pixel data a(i,j) of the present frame from the second input line 91 in FIG. 6, not delayed.", "The subtracter 134 subtracts the interpolation pixel data b 1 k (i,j) from the pixel data a(i,j) of the present frame.", "As a result of the subtraction, the subtracter 134 detects a difference between the pixel data a(i,j) of the present frame and the interpolation pixel data b 1 k (i,j).", "Then, the subtracter 134 supplies the detected difference to a first register 136.", "The first register 136 temporarily stores the inter-pixel difference from the subtracter 134 and supplies the temporarily stored inter-pixel difference to an absolute value calculator 138.", "In result, the first register 136 acts to safely transfer the inter-pixel difference from the subtracter 134 to the absolute value calculator 138.", "The absolute value calculator 138 obtains an absolute value of the inter-pixel difference from the first register 136 and supplies the obtained absolute value to a second register 140.", "The MAD detector further includes an accumulator 142 for inputting the absolute value of the inter-pixel difference from the second register 140.", "The accumulator 142 adds the absolute value of the inter-pixel difference from the second register 140 to the present MAD fed back from its output line and transfers the resultant MAD to a third register 144.", "The third register 144 transfers the MAD from the accumulator 142 to the comparator 118 in FIG. 6 through an output line 139.", "FIG. 9 is a table illustrating the output data from the interpolation circuit 90 and the MADs from the first to ninth MAD detectors 100, 102, 104, 106, 108, 110, 112, 114 and 116 with respect to the 5×5 pixel data from the first input line 81 in FIG. 6. As seen from this drawing, the improved motion vector extractor performs the calculating operation once to extract the motion vector.", "As apparent from the above description, the improved motion vector extractor of the present invention has the effect of shortening the motion vector extracting time.", "Also, the improved motion vector extractor of the present invention can produce the interpolation pixel data without resorting to parallel MAD processing as discussed in the Description of the Prior Art.", "Therefore, the circuit can be simplified in construction.", "Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims." ]
CROSS REFERENCE TO RELATED APPLICATION This is the 35 USC 371 national stage of International application PCT/FR99/00931 filed on Apr. 20, 1999, which designated the United States of America. FIELD OF THE INVENTION The invention relates to an air distillation process with production of argon by means of an air distillation plant comprising an air distillation apparatus and at least one column for production of impure argon, the plant being intended to deliver argon with a nominal argon extraction yield ρ n at the outlet of the said impure-argon production column. BACKGROUND OF THE INVENTION The invention applies in particular to the production of argon by means of air distillation plants having a double distillation column. In such a plant with a double air distillation column, medium-pressure nitrogen is generally removed from the top of the medium-pressure column of the double column. This medium-pressure nitrogen is generally used, after expansion in a turbine, as a source of refrigeration, especially to cool the air to be distilled. Thus, a portion of the refrigeration energy supplied to the air to be distilled can be recovered and therefore the operating costs of such a plant can be reduced. Such a plant is designed to meet nominal argon production requirements with a nominal argon extraction yield ρ n at the outlet of the impure-argon production column, called the mixture column. In general, it is sought to have a maximum yield ρ n . Hitherto, when the argon production requirements decrease, for example during periods of less load on a consuming plant or when storage tanks to be filled are full, the argon extraction yield ρ at the outlet of the impure-argon production column is correspondingly reduced in order to meet at the very most these reduced argon-proauction requirements. SUMMARY OF THE INVENTION The object of the invention is to provide an air distillation process with production of argon allowing the operating costs to be optimized when the argon-production requirements are less than the nominal requirements. For this purpose, the subject of the invention is an air distillation process with production of argon by means of an air distillation plant comprising an air distillation apparatus and at least one column for production of impure argon, the plant being designed to deliver argon with a nominal argon extraction yield ρ n at the outlet of the said impure-argon production column, characterized in that, for reduced argon production requirements corresponding to a necessary argon extraction yield ρ at the outlet of the impure-argon production column with ρ≦ρ o ≦ρ n , where ρ o is a predetermined optimum yield, the argon extraction yield at the outlet of the impure-argon production column is maintained at approximately the value ρ o . Depending on the particular embodiments, the process may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination: the argon extracted in excess with respect to the necessary extraction yield ρ is used as a source of refrigeration in the air distillation plant, for example to cool the air to be distilled; the said excess argon is at least partially withdrawn in gas and/or liquid form at the top of the impure-argon production column and this withdrawn portion is sent into at least one heat exchanger of the plant or into the air distillation apparatus; the said at least partially withdrawn portion is mixed with a residual fluid withdrawn from one of the columns of the plant before it is sent into the said heat exchanger; the said at least partially withdrawn portion is mixed with a fluid intended for one of the columns of the plant; since the plant also comprises a column for production of nearly pure argon by argon removal connected to the said impure-argon production column, at least a portion of the excess argon is withdrawn in gas and/or liquid form at the bottom or at the top of the pure-argon production column and this withdrawn portion is sent into at least one heat exchanger of the plant or into the air distillation apparatus; since the air distillation apparatus comprises a double column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, medium-pressure nitrogen is withdrawn from the top of the medium-pressure column, ρ o is the yield for which medium-pressure nitrogen can be withdrawn at a maximum flow rate D(ρ o ) and, for a necessary extraction yield ρ of less than ρ o , medium-pressure nitrogen is withdrawn at a flow rate of greater than D(ρ); for a necessary extraction yield ρ of less than ρ o , medium-pressure nitrogen is withdrawn at the maximum flow rate D(ρ o ); the medium-pressure nitrogen withdrawn as source of refrigeration in the plant is used by sending it, especially after expansion in a turbine, in a heat exchanger of the plant, for example to cool the air to be distilled; since the air distillation apparatus comprises a double column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, medium-pressure nitrogen is withdrawn from the top of the medium-pressure column, ρ o is the yield for which air can be expanded to the low pressure at a maximum flow rate D′ (ρ o ) with the performance of external work, for the purpose of blowing it into the low-pressure column, and, for a necessary extract-ion yield ρ of less than ρ o , air is expanded to the low pressure, with the performance of external work, at a flow rage greater than D′ (ρ o ), and especially a flow rate equal to D′ (ρ o ) The subject of the invention is also a plant for the implementation of the process as defined above, characterized in that it comprises an air distillation apparatus, at least one impure-argon production column, a heat exchanger, especially one through which a feed line for air to be distilled passes, and at least one branch line for sending at least one portion of the argon extracted in excess into the said heat exchanger. Depending on the particular embodiments, the plant may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination: an inlet of the said branch line is connected to an outlet for liquid or gaseous argon from the top of the impure-argon production column; the plant comprises a nearly-pure argon production column connected to the impure-argon production column, and an inlet of the said branch line is connected to an outlet for gas or liquid from the bottom or from the top of the nearly-pure argon production column; the said branch line is connected to an outlet for residual fluid from one of the columns of the plant in order to mix a residual fluid with the argon conveyed in the said branch line; the said branch line is connected to an inlet for fluid into one of the columns of the plant in order to mix the fluid with the argon conveyed in the said branch line; the distillation apparatus comprises a double distillation column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, the top of the medium-pressure column has a medium-pressure nitrogen outlet and a line connects the said medium-pressure nitrogen outlet to a heat exchanger of the plant, especially one through which a feed line for air to be distilled passes; the said line is provided with a turbine for expanding the medium-pressure nitrogen withdrawn; and the plant comprises a turbine for blowing purified air into the low-pressure column. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more clearly understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings in which: FIG. 1 is a diagrammatic view of an air distillation plant with production of argon according to the invention; FIG. 2 is an enlarged partial view of a variant of the plant in FIG. 1, illustrating the region around the impure-argon production column; FIG. 3 is a view similar to FIG. 1, illustrating a second embodiment of an air distillation plant according to the invention; FIG. 4 is a diagrammatic partial view of another embodiment of an air distillation plant according to the invention; FIG. 5 is a view similar to FIG. 1, illustrating a third embodiment of an air distillation plant according to the invention; and FIG. 6 is a view similar to FIG. 3, illustrating a fourth embodiment of an air distillation apparatus according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an air distillation plant 1 with production of argon. This plant 1 essentially comprises a double air distillation column 2 , an impure-argon production column 3 , called a mixture column, a pure-argon production column 4 , called a nitrogen-removal column, a main heat-exchange line 5 , a main compressor 6 for the air to be distilled and an apparatus 7 for purifying the air to be distilled. The double column 2 comprises a medium-pressure column, operating at a medium pressure of, for example, 6 bar absolute, a low-pressure column 9 , operating at a low pressure of less than the medium pressure, for example a pressure slightly above 1 bar absolute, and a main reboiler 10 . The impure-argon production column 3 comprises a top condenser 12 for partially condensing the impure argon from the top of the column 3 . The pure-argon production column 4 comprises a top condenser 13 and a bottom boiler 14 . A gas line 16 , called an argon bleed line, connects an intermediate point in the low-pressure column 9 to the bottom of the impure-argon production column 3 , from the base of which column 3 a liquid return line 17 rejoins the column 9 , at approximately the same level as the line 16 . A gas line 19 connects an outlet of the top condenser 12 of the column 3 to an intermediate level in the nearly-pure argon production column 4 . This line draws off that portion of the impure argon at the top of the column 3 that has not condensed in the condenser 12 . This line 19 passes from the column 3 in succession through a heat exchanger 20 , in order to condense the gaseous impure argon, and an expansion valve 21 , in order to expand this condensed impure argon. The gaseous air to be distilled, compressed by the compressor 6 and purified of water and of CO 2 , for example by adsorption, in the apparatus 7 is divided into two primary streams. The first primary air stream is cooled in the main heat-exchange line 5 and then split into two secondary streams. The first secondary stream is injected into the bottom of the medium-pressure column near its dew point. The second secondary stream is sent into the bottom vaporizer 14 of the pure-argon production column 4 , where this second secondary stream is liquefied, by vaporizing the argon in the bottom of this column 4 . The liquid thus produced is sent via a line 23 into the bottom of the medium-pressure column 8 . The second primary air stream, compressed and purified, is pressurized by a compressor 230 , then liquefied on passing through the main heat-exchange line 5 and expanded in an expansion valve 231 down to approximately the pressure prevailing in the medium-pressure column 8 . A first portion of this stream is then injected into the medium-pressure column 8 at an intermediate level. The other portion of this stream is supercooled on passing through a heat exchanger 24 , then expanded in an expansion valve 240 and injected into the low-pressure column 9 at an intermediate level. The reboiler 10 vaporizes the liquid oxygen in the bottom of the low-pressure column 9 by condensation of the nitrogen at the top of the medium-pressure column 8 . “Rich liquid” LR (i.e. liquid enriched with oxygen) is withdrawn from the bottom of the medium-pressure column 8 , then supercooled in the heat exchanger 24 and finally split into two streams. The first stream is sent, after expansion in an expansion valve 25 , into the low-pressure column 9 at an intermediate level. The second stream is sent, after expansion in an expansion valve 26 into the top condenser 12 of the impure-argon production column 3 , where this second stream is vaporized, by condensing the impure argon at the top of the column 3 . The gas thus produced is sent back, via a line 27 , into the low-pressure column 9 at an intermediate level below that at which the first stream of rich liquid was injected. “Depleted liquid” (almost pure nitrogen) LP is bled from the upper part of the medium-pressure column 8 , then supercooled in the heat exchanger 24 and finally split into three streams. The first stream is expanded in an expansion valve 30 and then injected into the top of the low-pressure column 9 . The second stream is expanded in an expansion valve 31 , then vaporized in the heat exchanger 20 , by condensing the impure argon conveyed by the line 19 , and then this vaporized stream is again expanded in an expansion valve 32 . Next, this second stream is sent back via a residue line 33 into the heat exchanger 24 where this second stream is warmed by cooling the liquids LP and LR passing through the exchanger 24 . Finally, this second stream is sent into the main heat-exchange line 5 , where this second stream is warmed, thus helping to cool the air to be distilled. The third stream of depleted liquid is expanded in an expansion valve 34 before being sent into the top condenser 13 of the pure-argon production column 4 , where this third stream is vaporized by condensing the impure nitrogen at the top of the column 4 . The gas thus produced is sent, after expansion in an expansion valve 35 , into the residue line 33 in order to be warmed, on the one hand, in the heat exchanger 24 , thus cooling the liquids LP and LR, and, on the other hand, in the main heat-exchange line 5 , thereby helping to cool the air to be distilled. Impure or residual nitrogen NR, withdrawn from the top of the low-pressure column 9 , are [sic] sent into the residue line 33 where this impure nitrogen is warmed on passing through the heat exchanger 24 and then the main heat-exchange line 5 . Liquid oxygen OL, withdrawn from the bottom of the low-pressure column 9 , is pumped by a pump 37 and then sent via a line 38 into the main heat-exchange line 5 where this liquid oxygen is vaporized, thereby helping to cool the air to be distilled. Medium-pressure gaseous nitrogen NGMP is bled from the top of the medium-pressure column 8 and then sent via a line 39 to the heat-exchange line 5 in order to help to cool the air to be distilled. In an intermediate region of this heat-exchange line 5 , the medium-pressure gaseous nitrogen is split into two streams. The first stream passes through the rest of the line 5 , where it is warmed and then delivered via a production line 40 , for example in order to feed a plant 140 where it is consumed. The second stream is expanded in a turbine 41 and then sent into the residue line 33 at the cold end of the heat-exchange line 5 in order again to help to cool the air to be distilled. Medium-pressure liquid nitrogen NLMP is withdrawn from the top of the medium-pressure column 8 and then sent via a line 43 into the heat exchanger 24 , where this liquid nitrogen is supercooled by warming the residual gases conveyed by the residue line 33 . Next, this liquid nitrogen is delivered, for example, by feeding, after expansion in an expansion valve 143 , a storage tank 144 . Nearly pure liquid argon ArL is withdrawn from the bottom of the column 4 and then delivered via a production line 45 . Impure or residual nitrogen is bled off from the top of the column 4 and then removed via a line 46 . The plant 1 furthermore comprises a branch line 48 , the inlet 49 of which is connected to the line 19 , between the heat exchanger 20 and the expansion valve 21 , and the outlet 50 of which emerges in the residue line 33 just upstream of the heat exchanger 24 . The role of this branch line 48 will be described later. The medium-pressure column 8 has, for example, 40 theoretical trays and the low-pressure column 9 has, for example, 65 theoretical trays. The plant 1 is designed, for example, to handle an air flow rate of 1000 Nm 3 /h and to extract 207.4 Nm 3 /h of pure oxygen, 6.4 Nm 3 /h of pure argon and 160 Nm 3 /h of medium-pressure gaseous nitrogen. These numbers correspond to the nominal operation of the plant 1 . The nominal argon extraction yield ρ n at the outlet of the impure-argon production column 3 is approximately 69%. This yield ρ n is in this case equal to the optimum argon extraction yield ρ o with respect to the amount of medium-pressure nitrogen that can be withdrawn from the top of the medium-pressure column 8 . When the argon supply requirements decrease, for example for constant oxygen supply requirements, the argon extraction yield ρ at the outlet of the column 3 necessary to meet these reduced requirements is less than ρ o . However, the extraction yield is maintained at the value ρ o and the excess argon thus extracted at the outlet of the impure-argon production column 3 is sent back into the residue line 33 via the branch line 48 . Thus, by maintaining the extraction yield ρ at the value ρ o , the flow rate D at which medium-pressure nitrogen can be withdrawn from the top of the medium-pressure column 8 is maintained at the maximum value D(ρ o ) In contrast, if, as in the prior art, argon were to be produced with an argon extraction yield ρ<ρ o corresponding to the argon supply requirements, the flow rate D(ρ) at which medium-pressure nitrogen can be withdrawn would be less than D(ρ o ) Table I below illustrates this observation. TABLE I Case Case Case Case Case 1 2A 2B 3A 3B D (air) 1000 1000 1000 1000 1000 (Nm 3 /h) D (oxygen) 207.5 207.5 207.5 207.5 207.5 (Nm 3 /h) D (argon) Extracted from 6.4 2.8 6.4 0 6.4 (Nm 3 /h) the mixture column Amount −6.4 −2.8 −2.8 0 0 produced (ArL) D (NGMP) Total 160 130 160 100 160 Expanded in 80 52 52 30 30 the turbine Amount 80 78 108 70 130 remaining Gain (NGMP) NGMP 30 60 Energy −3% −6% In this table, Case 1 corresponds to the nominal operating conditions of the plant 1 . Cases 2 A and 2 B correspond to the operation of the plant for argon supply requirements of less than the nominal requirements, these corresponding to a necessary argon extraction yield ρ at the outlet of the column 3 of approximately 30%. Cases 3 A and 3 B correspond to the operation of the argon plant 1 for zero argon supply requirements, these therefore corresponding to a necessary argon extraction yield p of 0%. The letters A and B correspond to the implementation of a process according to the prior art and to the implementation of a process according to the invention, respectively. In these cases, it is assumed that the medium-pressure liquid nitrogen is bled off at a constant flow rate. It may therefore be seen that the process according to the invention makes it possible to maintain the amount of medium-pressure gaseous nitrogen bled off at its maximum level. The excess medium-pressure gaseous nitrogen thus extracted, i.e. D(ρ o )−D(ρ), makes it possible to reduce the energy necessary to operate the plant 1 by approximately 3% in Case 2 B compared with Case 2 A and by approximately 6% in Case 3 B compared with Case 3 A. More generally, the excess medium-pressure nitrogen obtained by implementing the process may be used in various ways. Thus, this excess may be bled off in liquid and/or gas form from the top of the medium-pressure column 8 , utilized by delivering it to a plant where it is consumed, or used as a source of refrigeration in the plant 1 . It is thus possible, for example, to increase the amount of medium-pressure gaseous nitrogen expanded in the turbine 41 and therefore, for example, to reduce the amount of liquid oxygen passing through the main heat-exchange line 5 . Thus, a line 52 (shown dotted in FIG. 1) may allow liquid oxygen to be produced directly. As a variant, it is possible, during periods in which excess argon is extracted, to withdraw medium-pressure nitrogen at a flow rate D which is such that D(ρ)<D<D(ρ o ), where ρ is the necessary extraction yield. The branch line 48 makes it possible to recover the refrigerating energy of the argon extracted in excess from the outlet of the impure-argon production column 3 . This argon produced in excess is in fact used as a source of refrigeration in the heat exchanger 24 and in the heat-exchange line 5 . As a variant, this branch line 48 may be omitted, the excess argon extracted then being vented, or the inlet of this branch line 48 may thus be connected to other points in the plant 1 . The inlet 49 of the line 48 may be connected to the bottom or to the top of the pure-argon production column 4 in order to bleed off the excess argon extracted via the column 3 . The inlet 49 of the line 48 may also be connected to the top of the impure-argon production column 3 in order to bleed off the gaseous impure argon, as illustrated in FIG. 2 . According to other variants, the branch line 48 may pass independently through the heat exchanger 24 and/or the main heat-exchange line 5 , without the excess argon extracted being mixed with a residual gas. Depending on the variants, and on the characteristics of the air distillation apparatus 2 used, the optimum yield ρ o may be different from the nominal yield ρ n . This yield ρ o is generally less than ρ n . In this case, the argon extraction yield is maintained at the value ρ o for argon supply requirements corresponding to a necessary yield ρ<ρ o <ρ n . In the plant 1 described, the extraction yield ρ o is the optimum with respect to the amount of medium-pressure nitrogen that can be withdrawn from the top of the medium-pressure column 8 . However, depending on the type of plant and in particular on the nature of the air distillation apparatus 2 used, this extraction yield may be the optimum with respect to other quantities. A first example, illustrated in FIG. 3, relates to air distillation plants in which the refrigeration is produced by an air-blowing turbine. As is known, this turbine 501 is placed in a line 502 which connects the outlet of the air purification apparatus 7 to the low-pressure column 9 at an intermediate level, and which passes at least partially through the heat-exchange line 5 . The turbine 501 expands air, purified by the apparatus 7 and then compressed by an auxiliary compressor 503 coupled to the turbine 501 , to the low pressure to within the pressure drops. This air-blowing turbine 501 provides the refrigeration of the plant 1 instead of the turbine 41 in FIG. 1 . In such a case, the yield ρ o may be the optimum yield for a predetermined amount of medium-pressure gaseous nitrogen withdrawn from the top of the medium-pressure column 9 with respect to the amount of air expanded in the air-blowing turbine. Thus, by keeping the argon extraction yield ρ at the value ρ o , a maximum amount of air is expanded in the air-blowing turbine, thereby making it possible, as previously, to maximize the amount of refrigeration produced. FIG. 4 illustrates a second example in which the air distillation apparatus 2 is a single distillation column. In this case, impure nitrogen NC is withdrawn from the top of the column 2 , then warmed in a heat exchanger 51 , compressed in a compressor 52 and cooled in the exchanger 51 by heat exchange with the nitrogen NC to be compressed. Next, this compressed and cooled nitrogen is liquefied, by vaporizing the oxygen in the bottom of the column 2 . Next, the liquefied nitrogen is expanded in an expansion valve 53 and then reintroduced into the top of the column 2 . The yield ρ o then corresponds approximately to the minimum flow rate of impure nitrogen NC at the top that has to be used to vaporize the oxygen at the bottom. Thus, maintaining the argon extraction yield at ρ o during periods of reduced argon supply requirements makes it possible to reduce the compression energy delivered to the cycle compressor 52 and therefore the operating costs of the plant 1 . According to the example in FIG. 5, the liquid argon from the condenser 20 is sent to the point 50 where it is mixed with impure nitrogen (lower depleted liquid) withdrawn from the medium-pressure column 8 at an intermediate level and sent into the line 133 . The mixture is partly sent into the top of the low-pressure column 9 after expansion in the valve 30 . One portion of the mixture is sent after expansion in the valve 31 to the condenser 20 and another portion is sent after expansion in the valve 34 to the condenser 13 . The rest of the apparatus is identical to that in FIG. 1 . According to the example in FIG. 6, the gas produced by vaporization in the condenser 13 is expanded in the valve 35 and mixed with the residual nitrogen from the low-pressure column 9 . The liquid argon from the bottom of the column 4 is sent partly into the line 33 . The gas vaporized by the condenser 20 is expanded in 32 and optionally mixed with the liquid argon in the branch line 48 . Next, the liquid argon is mixed with the lower depleted liquid of the medium-pressure column and sent into the top of the low-pressure column after expansion. Any impure argon from the line 19 is sent into the pure-argon production column 4 . The rest of the apparatus is identical to that in FIG. 3 . More generally, the process according to the invention makes it possible to reduce the energy to be delivered to air distillation plants with production of argon. The refrigerating capacity of the apparatus may be produced partly by a Claude turbine or a hydraulic turbine. The process may also produce pressurized nitrogen by withdrawing liquid nitrogen from the medium-pressure column, pressurizing it and vaporizing it in the exchange line. Nevertheless, the process does not necessarily include the pressurization of a liquid before it is vaporized in the exchange line. The air separation apparatus may be a triple column or may include a mixing column.
A method for air distillation with production of argon using an air distilling installation (1) comprising an air distilling apparatus (2) in particular with double column, and at least one column for producing impure argon. The installation has dimensions for supplying argon with a nominal yield ρ n of argon extraction at the impure argon producing column output. For reduced argon production requirements corresponding to a required yield ρ of argon extraction at the impure argon producing column output, with ρ≦ρ o ≦ρ n where ρ o is a predetermined optimal yield, the argon extraction yield in the impure argon producing column is maintained at the value ρ o .
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "CROSS REFERENCE TO RELATED APPLICATION This is the 35 USC 371 national stage of International application PCT/FR99/00931 filed on Apr. 20, 1999, which designated the United States of America.", "FIELD OF THE INVENTION The invention relates to an air distillation process with production of argon by means of an air distillation plant comprising an air distillation apparatus and at least one column for production of impure argon, the plant being intended to deliver argon with a nominal argon extraction yield ρ n at the outlet of the said impure-argon production column.", "BACKGROUND OF THE INVENTION The invention applies in particular to the production of argon by means of air distillation plants having a double distillation column.", "In such a plant with a double air distillation column, medium-pressure nitrogen is generally removed from the top of the medium-pressure column of the double column.", "This medium-pressure nitrogen is generally used, after expansion in a turbine, as a source of refrigeration, especially to cool the air to be distilled.", "Thus, a portion of the refrigeration energy supplied to the air to be distilled can be recovered and therefore the operating costs of such a plant can be reduced.", "Such a plant is designed to meet nominal argon production requirements with a nominal argon extraction yield ρ n at the outlet of the impure-argon production column, called the mixture column.", "In general, it is sought to have a maximum yield ρ n .", "Hitherto, when the argon production requirements decrease, for example during periods of less load on a consuming plant or when storage tanks to be filled are full, the argon extraction yield ρ at the outlet of the impure-argon production column is correspondingly reduced in order to meet at the very most these reduced argon-proauction requirements.", "SUMMARY OF THE INVENTION The object of the invention is to provide an air distillation process with production of argon allowing the operating costs to be optimized when the argon-production requirements are less than the nominal requirements.", "For this purpose, the subject of the invention is an air distillation process with production of argon by means of an air distillation plant comprising an air distillation apparatus and at least one column for production of impure argon, the plant being designed to deliver argon with a nominal argon extraction yield ρ n at the outlet of the said impure-argon production column, characterized in that, for reduced argon production requirements corresponding to a necessary argon extraction yield ρ at the outlet of the impure-argon production column with ρ≦ρ o ≦ρ n , where ρ o is a predetermined optimum yield, the argon extraction yield at the outlet of the impure-argon production column is maintained at approximately the value ρ o .", "Depending on the particular embodiments, the process may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination: the argon extracted in excess with respect to the necessary extraction yield ρ is used as a source of refrigeration in the air distillation plant, for example to cool the air to be distilled;", "the said excess argon is at least partially withdrawn in gas and/or liquid form at the top of the impure-argon production column and this withdrawn portion is sent into at least one heat exchanger of the plant or into the air distillation apparatus;", "the said at least partially withdrawn portion is mixed with a residual fluid withdrawn from one of the columns of the plant before it is sent into the said heat exchanger;", "the said at least partially withdrawn portion is mixed with a fluid intended for one of the columns of the plant;", "since the plant also comprises a column for production of nearly pure argon by argon removal connected to the said impure-argon production column, at least a portion of the excess argon is withdrawn in gas and/or liquid form at the bottom or at the top of the pure-argon production column and this withdrawn portion is sent into at least one heat exchanger of the plant or into the air distillation apparatus;", "since the air distillation apparatus comprises a double column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, medium-pressure nitrogen is withdrawn from the top of the medium-pressure column, ρ o is the yield for which medium-pressure nitrogen can be withdrawn at a maximum flow rate D(ρ o ) and, for a necessary extraction yield ρ of less than ρ o , medium-pressure nitrogen is withdrawn at a flow rate of greater than D(ρ);", "for a necessary extraction yield ρ of less than ρ o , medium-pressure nitrogen is withdrawn at the maximum flow rate D(ρ o );", "the medium-pressure nitrogen withdrawn as source of refrigeration in the plant is used by sending it, especially after expansion in a turbine, in a heat exchanger of the plant, for example to cool the air to be distilled;", "since the air distillation apparatus comprises a double column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, medium-pressure nitrogen is withdrawn from the top of the medium-pressure column, ρ o is the yield for which air can be expanded to the low pressure at a maximum flow rate D′ (ρ o ) with the performance of external work, for the purpose of blowing it into the low-pressure column, and, for a necessary extract-ion yield ρ of less than ρ o , air is expanded to the low pressure, with the performance of external work, at a flow rage greater than D′ (ρ o ), and especially a flow rate equal to D′ (ρ o ) The subject of the invention is also a plant for the implementation of the process as defined above, characterized in that it comprises an air distillation apparatus, at least one impure-argon production column, a heat exchanger, especially one through which a feed line for air to be distilled passes, and at least one branch line for sending at least one portion of the argon extracted in excess into the said heat exchanger.", "Depending on the particular embodiments, the plant may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination: an inlet of the said branch line is connected to an outlet for liquid or gaseous argon from the top of the impure-argon production column;", "the plant comprises a nearly-pure argon production column connected to the impure-argon production column, and an inlet of the said branch line is connected to an outlet for gas or liquid from the bottom or from the top of the nearly-pure argon production column;", "the said branch line is connected to an outlet for residual fluid from one of the columns of the plant in order to mix a residual fluid with the argon conveyed in the said branch line;", "the said branch line is connected to an inlet for fluid into one of the columns of the plant in order to mix the fluid with the argon conveyed in the said branch line;", "the distillation apparatus comprises a double distillation column which itself comprises a medium-pressure column, a low-pressure column and a reboiler for bringing the top of the medium-pressure column into heat-exchange relationship with the bottom of the low-pressure column, the top of the medium-pressure column has a medium-pressure nitrogen outlet and a line connects the said medium-pressure nitrogen outlet to a heat exchanger of the plant, especially one through which a feed line for air to be distilled passes;", "the said line is provided with a turbine for expanding the medium-pressure nitrogen withdrawn;", "and the plant comprises a turbine for blowing purified air into the low-pressure column.", "BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more clearly understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings in which: FIG. 1 is a diagrammatic view of an air distillation plant with production of argon according to the invention;", "FIG. 2 is an enlarged partial view of a variant of the plant in FIG. 1, illustrating the region around the impure-argon production column;", "FIG. 3 is a view similar to FIG. 1, illustrating a second embodiment of an air distillation plant according to the invention;", "FIG. 4 is a diagrammatic partial view of another embodiment of an air distillation plant according to the invention;", "FIG. 5 is a view similar to FIG. 1, illustrating a third embodiment of an air distillation plant according to the invention;", "and FIG. 6 is a view similar to FIG. 3, illustrating a fourth embodiment of an air distillation apparatus according to the invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an air distillation plant 1 with production of argon.", "This plant 1 essentially comprises a double air distillation column 2 , an impure-argon production column 3 , called a mixture column, a pure-argon production column 4 , called a nitrogen-removal column, a main heat-exchange line 5 , a main compressor 6 for the air to be distilled and an apparatus 7 for purifying the air to be distilled.", "The double column 2 comprises a medium-pressure column, operating at a medium pressure of, for example, 6 bar absolute, a low-pressure column 9 , operating at a low pressure of less than the medium pressure, for example a pressure slightly above 1 bar absolute, and a main reboiler 10 .", "The impure-argon production column 3 comprises a top condenser 12 for partially condensing the impure argon from the top of the column 3 .", "The pure-argon production column 4 comprises a top condenser 13 and a bottom boiler 14 .", "A gas line 16 , called an argon bleed line, connects an intermediate point in the low-pressure column 9 to the bottom of the impure-argon production column 3 , from the base of which column 3 a liquid return line 17 rejoins the column 9 , at approximately the same level as the line 16 .", "A gas line 19 connects an outlet of the top condenser 12 of the column 3 to an intermediate level in the nearly-pure argon production column 4 .", "This line draws off that portion of the impure argon at the top of the column 3 that has not condensed in the condenser 12 .", "This line 19 passes from the column 3 in succession through a heat exchanger 20 , in order to condense the gaseous impure argon, and an expansion valve 21 , in order to expand this condensed impure argon.", "The gaseous air to be distilled, compressed by the compressor 6 and purified of water and of CO 2 , for example by adsorption, in the apparatus 7 is divided into two primary streams.", "The first primary air stream is cooled in the main heat-exchange line 5 and then split into two secondary streams.", "The first secondary stream is injected into the bottom of the medium-pressure column near its dew point.", "The second secondary stream is sent into the bottom vaporizer 14 of the pure-argon production column 4 , where this second secondary stream is liquefied, by vaporizing the argon in the bottom of this column 4 .", "The liquid thus produced is sent via a line 23 into the bottom of the medium-pressure column 8 .", "The second primary air stream, compressed and purified, is pressurized by a compressor 230 , then liquefied on passing through the main heat-exchange line 5 and expanded in an expansion valve 231 down to approximately the pressure prevailing in the medium-pressure column 8 .", "A first portion of this stream is then injected into the medium-pressure column 8 at an intermediate level.", "The other portion of this stream is supercooled on passing through a heat exchanger 24 , then expanded in an expansion valve 240 and injected into the low-pressure column 9 at an intermediate level.", "The reboiler 10 vaporizes the liquid oxygen in the bottom of the low-pressure column 9 by condensation of the nitrogen at the top of the medium-pressure column 8 .", "“Rich liquid”", "LR (i.e. liquid enriched with oxygen) is withdrawn from the bottom of the medium-pressure column 8 , then supercooled in the heat exchanger 24 and finally split into two streams.", "The first stream is sent, after expansion in an expansion valve 25 , into the low-pressure column 9 at an intermediate level.", "The second stream is sent, after expansion in an expansion valve 26 into the top condenser 12 of the impure-argon production column 3 , where this second stream is vaporized, by condensing the impure argon at the top of the column 3 .", "The gas thus produced is sent back, via a line 27 , into the low-pressure column 9 at an intermediate level below that at which the first stream of rich liquid was injected.", "“Depleted liquid”", "(almost pure nitrogen) LP is bled from the upper part of the medium-pressure column 8 , then supercooled in the heat exchanger 24 and finally split into three streams.", "The first stream is expanded in an expansion valve 30 and then injected into the top of the low-pressure column 9 .", "The second stream is expanded in an expansion valve 31 , then vaporized in the heat exchanger 20 , by condensing the impure argon conveyed by the line 19 , and then this vaporized stream is again expanded in an expansion valve 32 .", "Next, this second stream is sent back via a residue line 33 into the heat exchanger 24 where this second stream is warmed by cooling the liquids LP and LR passing through the exchanger 24 .", "Finally, this second stream is sent into the main heat-exchange line 5 , where this second stream is warmed, thus helping to cool the air to be distilled.", "The third stream of depleted liquid is expanded in an expansion valve 34 before being sent into the top condenser 13 of the pure-argon production column 4 , where this third stream is vaporized by condensing the impure nitrogen at the top of the column 4 .", "The gas thus produced is sent, after expansion in an expansion valve 35 , into the residue line 33 in order to be warmed, on the one hand, in the heat exchanger 24 , thus cooling the liquids LP and LR, and, on the other hand, in the main heat-exchange line 5 , thereby helping to cool the air to be distilled.", "Impure or residual nitrogen NR, withdrawn from the top of the low-pressure column 9 , are [sic] sent into the residue line 33 where this impure nitrogen is warmed on passing through the heat exchanger 24 and then the main heat-exchange line 5 .", "Liquid oxygen OL, withdrawn from the bottom of the low-pressure column 9 , is pumped by a pump 37 and then sent via a line 38 into the main heat-exchange line 5 where this liquid oxygen is vaporized, thereby helping to cool the air to be distilled.", "Medium-pressure gaseous nitrogen NGMP is bled from the top of the medium-pressure column 8 and then sent via a line 39 to the heat-exchange line 5 in order to help to cool the air to be distilled.", "In an intermediate region of this heat-exchange line 5 , the medium-pressure gaseous nitrogen is split into two streams.", "The first stream passes through the rest of the line 5 , where it is warmed and then delivered via a production line 40 , for example in order to feed a plant 140 where it is consumed.", "The second stream is expanded in a turbine 41 and then sent into the residue line 33 at the cold end of the heat-exchange line 5 in order again to help to cool the air to be distilled.", "Medium-pressure liquid nitrogen NLMP is withdrawn from the top of the medium-pressure column 8 and then sent via a line 43 into the heat exchanger 24 , where this liquid nitrogen is supercooled by warming the residual gases conveyed by the residue line 33 .", "Next, this liquid nitrogen is delivered, for example, by feeding, after expansion in an expansion valve 143 , a storage tank 144 .", "Nearly pure liquid argon ArL is withdrawn from the bottom of the column 4 and then delivered via a production line 45 .", "Impure or residual nitrogen is bled off from the top of the column 4 and then removed via a line 46 .", "The plant 1 furthermore comprises a branch line 48 , the inlet 49 of which is connected to the line 19 , between the heat exchanger 20 and the expansion valve 21 , and the outlet 50 of which emerges in the residue line 33 just upstream of the heat exchanger 24 .", "The role of this branch line 48 will be described later.", "The medium-pressure column 8 has, for example, 40 theoretical trays and the low-pressure column 9 has, for example, 65 theoretical trays.", "The plant 1 is designed, for example, to handle an air flow rate of 1000 Nm 3 /h and to extract 207.4 Nm 3 /h of pure oxygen, 6.4 Nm 3 /h of pure argon and 160 Nm 3 /h of medium-pressure gaseous nitrogen.", "These numbers correspond to the nominal operation of the plant 1 .", "The nominal argon extraction yield ρ n at the outlet of the impure-argon production column 3 is approximately 69%.", "This yield ρ n is in this case equal to the optimum argon extraction yield ρ o with respect to the amount of medium-pressure nitrogen that can be withdrawn from the top of the medium-pressure column 8 .", "When the argon supply requirements decrease, for example for constant oxygen supply requirements, the argon extraction yield ρ at the outlet of the column 3 necessary to meet these reduced requirements is less than ρ o .", "However, the extraction yield is maintained at the value ρ o and the excess argon thus extracted at the outlet of the impure-argon production column 3 is sent back into the residue line 33 via the branch line 48 .", "Thus, by maintaining the extraction yield ρ at the value ρ o , the flow rate D at which medium-pressure nitrogen can be withdrawn from the top of the medium-pressure column 8 is maintained at the maximum value D(ρ o ) In contrast, if, as in the prior art, argon were to be produced with an argon extraction yield ρ<ρ o corresponding to the argon supply requirements, the flow rate D(ρ) at which medium-pressure nitrogen can be withdrawn would be less than D(ρ o ) Table I below illustrates this observation.", "TABLE I Case Case Case Case Case 1 2A 2B 3A 3B D (air) 1000 1000 1000 1000 1000 (Nm 3 /h) D (oxygen) 207.5 207.5 207.5 207.5 207.5 (Nm 3 /h) D (argon) Extracted from 6.4 2.8 6.4 0 6.4 (Nm 3 /h) the mixture column Amount −6.4 −2.8 −2.8 0 0 produced (ArL) D (NGMP) Total 160 130 160 100 160 Expanded in 80 52 52 30 30 the turbine Amount 80 78 108 70 130 remaining Gain (NGMP) NGMP 30 60 Energy −3% −6% In this table, Case 1 corresponds to the nominal operating conditions of the plant 1 .", "Cases 2 A and 2 B correspond to the operation of the plant for argon supply requirements of less than the nominal requirements, these corresponding to a necessary argon extraction yield ρ at the outlet of the column 3 of approximately 30%.", "Cases 3 A and 3 B correspond to the operation of the argon plant 1 for zero argon supply requirements, these therefore corresponding to a necessary argon extraction yield p of 0%.", "The letters A and B correspond to the implementation of a process according to the prior art and to the implementation of a process according to the invention, respectively.", "In these cases, it is assumed that the medium-pressure liquid nitrogen is bled off at a constant flow rate.", "It may therefore be seen that the process according to the invention makes it possible to maintain the amount of medium-pressure gaseous nitrogen bled off at its maximum level.", "The excess medium-pressure gaseous nitrogen thus extracted, i.e. D(ρ o )−D(ρ), makes it possible to reduce the energy necessary to operate the plant 1 by approximately 3% in Case 2 B compared with Case 2 A and by approximately 6% in Case 3 B compared with Case 3 A. More generally, the excess medium-pressure nitrogen obtained by implementing the process may be used in various ways.", "Thus, this excess may be bled off in liquid and/or gas form from the top of the medium-pressure column 8 , utilized by delivering it to a plant where it is consumed, or used as a source of refrigeration in the plant 1 .", "It is thus possible, for example, to increase the amount of medium-pressure gaseous nitrogen expanded in the turbine 41 and therefore, for example, to reduce the amount of liquid oxygen passing through the main heat-exchange line 5 .", "Thus, a line 52 (shown dotted in FIG. 1) may allow liquid oxygen to be produced directly.", "As a variant, it is possible, during periods in which excess argon is extracted, to withdraw medium-pressure nitrogen at a flow rate D which is such that D(ρ)<D<D(ρ o ), where ρ is the necessary extraction yield.", "The branch line 48 makes it possible to recover the refrigerating energy of the argon extracted in excess from the outlet of the impure-argon production column 3 .", "This argon produced in excess is in fact used as a source of refrigeration in the heat exchanger 24 and in the heat-exchange line 5 .", "As a variant, this branch line 48 may be omitted, the excess argon extracted then being vented, or the inlet of this branch line 48 may thus be connected to other points in the plant 1 .", "The inlet 49 of the line 48 may be connected to the bottom or to the top of the pure-argon production column 4 in order to bleed off the excess argon extracted via the column 3 .", "The inlet 49 of the line 48 may also be connected to the top of the impure-argon production column 3 in order to bleed off the gaseous impure argon, as illustrated in FIG. 2 .", "According to other variants, the branch line 48 may pass independently through the heat exchanger 24 and/or the main heat-exchange line 5 , without the excess argon extracted being mixed with a residual gas.", "Depending on the variants, and on the characteristics of the air distillation apparatus 2 used, the optimum yield ρ o may be different from the nominal yield ρ n .", "This yield ρ o is generally less than ρ n .", "In this case, the argon extraction yield is maintained at the value ρ o for argon supply requirements corresponding to a necessary yield ρ<ρ o <ρ n .", "In the plant 1 described, the extraction yield ρ o is the optimum with respect to the amount of medium-pressure nitrogen that can be withdrawn from the top of the medium-pressure column 8 .", "However, depending on the type of plant and in particular on the nature of the air distillation apparatus 2 used, this extraction yield may be the optimum with respect to other quantities.", "A first example, illustrated in FIG. 3, relates to air distillation plants in which the refrigeration is produced by an air-blowing turbine.", "As is known, this turbine 501 is placed in a line 502 which connects the outlet of the air purification apparatus 7 to the low-pressure column 9 at an intermediate level, and which passes at least partially through the heat-exchange line 5 .", "The turbine 501 expands air, purified by the apparatus 7 and then compressed by an auxiliary compressor 503 coupled to the turbine 501 , to the low pressure to within the pressure drops.", "This air-blowing turbine 501 provides the refrigeration of the plant 1 instead of the turbine 41 in FIG. 1 .", "In such a case, the yield ρ o may be the optimum yield for a predetermined amount of medium-pressure gaseous nitrogen withdrawn from the top of the medium-pressure column 9 with respect to the amount of air expanded in the air-blowing turbine.", "Thus, by keeping the argon extraction yield ρ at the value ρ o , a maximum amount of air is expanded in the air-blowing turbine, thereby making it possible, as previously, to maximize the amount of refrigeration produced.", "FIG. 4 illustrates a second example in which the air distillation apparatus 2 is a single distillation column.", "In this case, impure nitrogen NC is withdrawn from the top of the column 2 , then warmed in a heat exchanger 51 , compressed in a compressor 52 and cooled in the exchanger 51 by heat exchange with the nitrogen NC to be compressed.", "Next, this compressed and cooled nitrogen is liquefied, by vaporizing the oxygen in the bottom of the column 2 .", "Next, the liquefied nitrogen is expanded in an expansion valve 53 and then reintroduced into the top of the column 2 .", "The yield ρ o then corresponds approximately to the minimum flow rate of impure nitrogen NC at the top that has to be used to vaporize the oxygen at the bottom.", "Thus, maintaining the argon extraction yield at ρ o during periods of reduced argon supply requirements makes it possible to reduce the compression energy delivered to the cycle compressor 52 and therefore the operating costs of the plant 1 .", "According to the example in FIG. 5, the liquid argon from the condenser 20 is sent to the point 50 where it is mixed with impure nitrogen (lower depleted liquid) withdrawn from the medium-pressure column 8 at an intermediate level and sent into the line 133 .", "The mixture is partly sent into the top of the low-pressure column 9 after expansion in the valve 30 .", "One portion of the mixture is sent after expansion in the valve 31 to the condenser 20 and another portion is sent after expansion in the valve 34 to the condenser 13 .", "The rest of the apparatus is identical to that in FIG. 1 .", "According to the example in FIG. 6, the gas produced by vaporization in the condenser 13 is expanded in the valve 35 and mixed with the residual nitrogen from the low-pressure column 9 .", "The liquid argon from the bottom of the column 4 is sent partly into the line 33 .", "The gas vaporized by the condenser 20 is expanded in 32 and optionally mixed with the liquid argon in the branch line 48 .", "Next, the liquid argon is mixed with the lower depleted liquid of the medium-pressure column and sent into the top of the low-pressure column after expansion.", "Any impure argon from the line 19 is sent into the pure-argon production column 4 .", "The rest of the apparatus is identical to that in FIG. 3 .", "More generally, the process according to the invention makes it possible to reduce the energy to be delivered to air distillation plants with production of argon.", "The refrigerating capacity of the apparatus may be produced partly by a Claude turbine or a hydraulic turbine.", "The process may also produce pressurized nitrogen by withdrawing liquid nitrogen from the medium-pressure column, pressurizing it and vaporizing it in the exchange line.", "Nevertheless, the process does not necessarily include the pressurization of a liquid before it is vaporized in the exchange line.", "The air separation apparatus may be a triple column or may include a mixing column." ]
This is a continuation of application Ser. No. 503,578, filed June 13, 1983, now abandoned. FIELD OF THE INVENTION The invention concerns an adhesive transfer tape which makes electrically and thermally conductive bonds such as are desirable for attaching a semiconductor die or chip to an electrically and thermally conductive substrate, a use previously served primarily by spreadable adhesives or by strips of solder or eutectic alloy. BACKGROUND ART Semiconductors such as integrated circuits are formed on wafers which are then cut into dice or chips that individually may be mounted onto substrates. Usually the substrate is electrically and thermally conductive, and mounting provides both good electrical and good thermal conductivity between the die and the substrate. Good thermal conductivity permits the substrate to serve as a heat sink for the die. An effective heat sink is desirable, because as a rule of thumb, an increase of 10° C. in the operating temperature of a semiconductor die reduces its life by one-half. Generally the attainment of good thermal conductivity is inherently accompanied by adequate electrical conductivity. Of the two prevalent techniques for attaching a semiconductor die to an electrically and thermally conductive substrate, one employs a solder or eutectic alloy such as a gold-silicon alloy. While such alloys provide excellent electrical and thermal conductivity, they are exceedingly expensive. Also, their application temperatures may be so high that some dice might be damaged, and differences in thermal expansion sometimes cause a die to break. Furthermore, it is difficult to handle an individual die together with an alloy strip of the same size. Because of the expense and difficulties in using eutectic alloys, it has become more common to employ a spreadable die attach adhesive consisting of a heat-curing epoxy resin composition filled with fine metal particles, usually silver and occasionally gold. Spreadable epoxy adhesives can be difficult to use, especially those which are marketed in two parts and must be thoroughly mixed shortly before use. Care must be taken to keep the metal particles in suspension, to spread out a uniform layer of the proper thickness, and not to allow voids in the adhesive layer. Automated attachment of dice to substrates is complicated by the waiting period during which the epoxy composition is cured. DISCLOSURE OF THE INVENTION The above-discussed difficulties of prior die attach systems are avoided in the present invention by an electrically and thermally conductive adhesive transfer tape which is easy to use and reliably attaches individual semiconductor dice to conductive substrates. As compared to metal-filled epoxy compositions, the novel adhesive transfer tape should be of comparable cost. Briefly, the adhesive transfer tape of the invention comprises a flexible, low-adhesion carrier web to which is lightly adhered a layer of adhesive containing electrically and thermally conductive particles which at the bonding temperature of the adhesive are at least as deformable as are substantially pure silver spherical particles at ordinary room temperature. The particles should be of uniform thickness. By "uniform" is meant that substantially all of the particles (disregarding fines, which are too difficult to eliminate) differ in diameters by no more than 2 to 1. The average thickness of the particles is greater than the thickness of the adhesive between particles, preferably from 10 to 100% greater. The particles are uniformly distributed throughout the layer or throughout preselected segments of the layer. When the particle-containing adhesive layer is removed from the carrier web and compressed between two flat, rigid plates, the particles are flattened to the thickness of the adhesive between particles. This provides small, flat conductive areas at both surfaces of the adhesive layer sufficient to provide good electrical and thermal contact between a die and a conductive substrate through each of the flattened particles. While being primarily useful as a die attach adhesive tape, the novel transfer tape can be used wherever it is desired to make an electrically conductive bond between two rigid, uniformly spaced surfaces. Although such uses may not require good thermal conductivity, this inherently is achieved due to the direct contact of each of the electrically and thermally conductive particles to each of the surfaces which are being bonded together. In one such use, the novel tape can be used for surface-mounted components of a printed circuit board. For example, a chip carrier having a plurality of conductive pads can be bonded by the novel transfer tape to connect each pad individually to a conductor in the printed circuit board. The adhesive layer of the novel tape provides good electrical conductivity through its thickness and good electrical insulation laterally, especially when the particles occupy less than 40% by volume of the adhesive layer. To economize the use of the electrically conductive particles, they may be located only in segments of the novel adhesive transfer tape which are to contact individual electrical conductors. This can be accomplished by the steps of: (1) coating onto a flexible, low-adhesion carrier web a viscous monomer composition which is radiation-polymerizable to an adhesive state, (2) selectively exposing the coating to radiation to polymerize segments of the monomer composition to a substantially tack-free adhesive state, (3) applying electrically conductive particles to the coating to become adhered only to the viscous monomer composition, and (4) again exposing the coating to radiation to polymerize the balance of the coating to a substantially tack-free adhesive state. Because the viscosity of a mixture of polymerizable monomers may be too low to provide desirably thin coatings, the monomers may be partially polymerized to provide a sufficiently viscous monomer composition, e.g., having a coatable viscosity within the range of 1000 to 40,000 cps. A second technique for locating electrically conductive particles only in preselected segments of the adhesive layer involves the steps of: (1) coating onto a flexible, low-adhesion carrier web a viscous monomer composition which is radiation-polymerizable to an adhesive state and contains electrically conductive particles, (2) selectively exposing the coating to radiation to polymerize segments of the monomer composition to a solvent-resistant adhesive state, (3) dissolving or otherwise removing portions of the coating between the polymerized adhesive segments, and (4) overcoating the entire segment-containing face of the carrier web with an adhesive such that the total thickness of both adhesive layers between particles is less than the average thickness of the particles. The adhesive applied in step (4) can be applied from solution or as a radiation-polymerizable monomer composition. A third technique is similar to the second except that instead of steps (1) and (2), an adhesive is applied from solution only onto preselected segments of the low-adhesion carrier, e.g., by silk screening. Preferably the adhesive of the novel transfer tape is heat-activatable, i.e., a thermosetting, hot-melt or hot-tackifying adhesive. Such adhesives usually are nontacky at ordinary room temperatures and, upon being activated by heat, flow sufficiently under pressure such that the faces of the small, flat conductive areas created at the surfaces of the adhesive layer should be free from adhesive. When the novel transfer tape has a heat-activatable adhesive, its low-adhesion carrier web preferably has sufficient resistance to heat to permit the adhesive to be heat-activated while being supported by the carrier web. Particularly useful carrier webs are polytetrafluoroethylene and polyimide films, both of which have good heat resistance, strength, dimensional stability, and age resistance. Also useful are biaxially-oriented polyethylene terephthalate, aromatic polyimide ("Kevlar"), and polyvinyl fluoride ("Tedlar") films. The adhesive layer of the novel adhesive transfer tape preferably is a polymer of alkyl acrylate and/or methacrylate having an average of 1-12 carbon atoms in the alkyl groups. Such a polymer provides better adhesion when it is a copolymer of monomers, up to 50 mol % of which is at least one copolymerizable monomer selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, amides of said acids, and N-vinyl-2-pyrrolidone. The acids should be minimized or avoided when electrical connections are to be made where corrosion might be a problem. Polymers based on alkyl acrylates having an average of 4-12 carbon atoms in their alkyl groups are pressure-sensitive adhesives and may have a weight-averaged T g in the range from -20° to -70° C. When the average is 1-3 or when a polymer is based on an alkyl methacrylate, the copolymer may have a weight-averaged T g in the range from -10° to -80° C. and be nontacky or poorly tacky at ordinary room temperatures, but become aggressively tacky when heated. An adhesive which is nontacky at ordinary room temperatures better holds electrically-conductive particles in place after the novel tape has been applied to make electrical connections. Hence, those electrical connections tend to be more secure and more resistant to brief exposure to soldering temperatures. Where such exposure is contemplated, a weight-averaged T g of from 30° to 80° C. is preferred. However, much the same result can be attained by crosslinking a polymer of lower T g after the electrical connections have been made, e.g., as taught in U.S. Pat. No. 2,925,174. The particles of the novel tape preferably are substantially spherical, a shape readily deformable to the thickness of the adhesive between particles. Preflattened particles such as those of U.S. Pat. No. 3,514,326 (Stow) can also be used but should be made of softer materials because pre-flattened particles are more resistant to further flattening. When pre-flattened particles are further flattened, there is a hazard of trapping adhesive between the areas particles and the surface against which they are further flattened. Whether pre-flattened or spherical, the particles preferably are made of a metal such as silver or gold or of laminated metals, one of which preferably is at least as deformable at the bonding temperature of the adhesive as is substantially pure silver at ordinary room temperatures. When a transfer tape of the invention has a heat-activatable adhesive, its particles may be laminates of materials, one of which melts at the activation temperature of the adhesive. Such a laminated particle may have a surface layer that melts and a core that does not melt at the activation temperature of the adhesive, for example, a solder surface layer and either a higher melting metal core such as copper or a nonmetallic core. Another useful laminated particle has a surface layer that does not melt and a core that melts at the activation temperature of the adhesive. The core of such a particle may be a solder, and its surface layer may be a higher melting metal such as silver or copper. Each of the particles of the novel tape may be an aggregate of tiny fused granules such as granules of a metal which is at least as deformable as substantially pure silver. Because the heat-activatable adhesive of the novel tape preferably is nontacky at ordinary ambient temperatures, the adhesive layer could be wound directly upon itself for storage and shipment. Since it is necessary to form the adhesive layer on a low-adhesion carrier web, it is convenient to wind the two together for storage and shipment. A preferred range of thicknesses for the adhesive between particles is from 0.01 to 0.05 mm, and the average particle thickness is preferably between 20 and 80% greater than the adhesive thickness between particles. When the particles have highly uniform thicknesses, excellent results are attained at an average particle diameter only 5% greater than the adhesive thickness between particles. When the particles comprise 5% by volume of the adhesive layer and their average thickness is one-third greater than the adhesive layer between particles, the average spacing between adjacent particles is about 0.13 mm when the adhesive thickness between particles is 0.02 mm. The average spacing may be as great as about 0.5 mm and preferably is within the range of 0.05 to 0.3 mm in order to insure a good overall electrical and thermal conductivity. While the novel tape preferably contains electrically and thermally conductive particles, equivalent results can be attained by substituting for the particles other electrically and thermally conductive elements which are as deformable as are the particles under the same conditions to provide small, flat conductive areas at both surfaces of the adhesive layer. For example, the electrically and thermally conductive elements may together form a metal foil, the thickness of which is less than that of the adhesive by itself, but which has at each surface of the layer protuberances that are closely spaced and uniformly distributed throughout the layer. The average distance between apices of the protuberances at one surface to those at the other surface should be greater than, perferably from 10% to 100% greater than, the thickness of the adhesive between protuberances. The protuberances may be provided by embossing the foil as in U.S. Pat. No. 3,497,383 (Olyphant) to form ridges at the surfaces of the adhesive layer that are flattened to provide narrow, elongated flat areas when the adhesive layer is compressed between two flat, rigid plates. Each upstanding portion of metal foil extending between an elongated flat area in one surface and the closest flat area in the other surface provides a metal element that conducts heat and electricity across the adhesive layer. Alternatively, a metal foil may have additional metal fused to its surfaces. For example, drops of silver or of a solder may be fused to a copper foil to provide protuberances, each of which is sufficiently soft to be flattened when the adhesive layer is compressed between two flat, rigid plates. The metal foil may have uniformly distributed perforations, in which event the adhesive layer of the novel tape may be continuous. When the metal foil is imperforate, the adhesive layer necessarily is separated by the foil into two laminae. Useful electrically and thermally conductive elements of the novel tape can also be provided by a wire screen of a conductive material which at the bonding temperature of the adhesive preferably is at least as deformable as is substantially pure silver at ordinary room temperature. The pressure applied to such a screen would not only provide small, flat areas on the wires at the surfaces of the adhesive layer but would also flatten the wires at their crossing points, thus enhancing the conductivity of the direct paths between the flattened surface areas. The novel adhesive transfer tape may be used as a die attach adhesive as follows. First, the tape is adhered by its heat-activated adhesive layer to the back surface of an undiced semiconductor wafer. The wafer is then diced while the carrier web serves the function for which wafer sawing films are currently used. Each resulting die has its own conductive adhesive layer by which it may be bonded to a conductive substrate after removal of the carrier web. If desired, the adhesive-bearing die may be stored indefinitely at room temperature before being adhesively attached to a substrate. Preferably the novel adhesive tape is used in connection with a conventional wafer sawing film. After bonding the tape by its own heat-activated adhesive tape to a semiconductor wafer and allowing the adhesive to cool, the carrier web is stripped away, and the exposed adhesive layer is adhered to the wafer sawing film by the low-tack adhesive of the wafer sawing film. Then while the wafer sawing film is stretched in a hoop fixture, the wafer and adhesive are diced. Care should be taken in selecting the wafer sawing film that its low-tack adhesive does not contaminate the adhesive of the novel tape. The adhesive layer of the novel tape may be transferred onto an adhesiveless backing of a wafer sawing film which has a low-adhesion surface. A semiconductor wafer may be bonded by the adhesive layer to the wafer sawing film and sawed into dice, each thus immediately having an electrically and thermally conductive adhesive layer. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings FIG. 1 is a schematic transverse cross-section of a die attach adhesive tape of the invention; FIG. 2 is a schematic transverse cross-section showing a semiconductor wafer to which the tape of FIG. 1 has been adhered and in turn mounted on a wafer sawing film for dicing; and FIG. 3 shows the use of an adhesive tape similar to that of FIGS. 1 and 2 being used to attach a semiconductor die to a conductive substrate. FIG. 4 is a schematic transverse cross-section of another embodiment of the adhesive tape of the invention; and FIG. 5 illustrates another schematic transverse cross-section of yet another embodiment of the adhesive tape of the invention. DETAILED DESCRIPTION The adhesive tape 10 of FIG. 1 has a flexible carrier web 12 having a low-adhesion surface 14 to which is lightly adhered a layer of adhesive 16 containing spherical electrically and thermally conductive metal particles 18, the diameters of which exceed the thickness of the adhesive 16 between particles. In FIG. 2, a piece of tape 10 has been adhered by its layer of adhesive 16 to a semiconductor wafer 20 and the carrier web 12 has been stripped off and discarded. The exposed layer of adhesive 16 has been pressed against the low-tack adhesive layer 21 of a conventional wafer sawing film 22 having a carrier web 24. While the wafer sawing film is stretched across a hoop fixture (not shown), the wafer 20 and the adhesive layer 16 are sawed at 26. Because the adhesive bond between the low-tack adhesive layer 21 and the carrier web 24 is stronger than the bond between the two adhesive layers, each die 20a and its adhesive layer 16a can be lifted off the wafer sawing film 22 and adhesively bonded to a conductive substrate to provide a composite similar to that illustrated in FIG. 3. FIG. 3 shows a die 30 which is bonded to an electrically and thermally conductive substrate 32 by a layer of heat-activated adhesive 34 containing electrically and thermally conductive laminated particles 36. Each of those particles has been flattened by pressing the die 30 against the substrate 32, and that part of the adhesive 34 which had covered the particles has been forced out from between the particles and the substrate 32, thus providing small, flat conductive areas at each surface of the layer of adhesive 34. Each particle 36 has a core 39 and a surface layer 38, one of which may have melted while the other did not melt at the temperature at which the adhesive 34 was activated. FIG. 4 illustrates another embodiment of the invention wherein adhesive tape 40 is illustrated containing wire screen 41 of a conductive material and adhesive 16. FIG. 5 illustrates adhesive tape 50 with embossed foil 51 and adhesive 16. In the following examples, all parts are given by weight unless otherwise noted. EXAMPLE 1 An acrylic polymer was made by mixing together 15.5 parts ethyl acrylate, 15.5 parts methyl acrylate, 1.65 parts acrylamide, 0.3 part gamma-methacryloxypropyltrimethoxysilane, 67 parts ethyl acetate and 0.1 part azo-bis-isobutylnitrile ("Vazo" 64 catalyst), purging the mixture with nitrogen to remove oxygen, and heating at 53°-55° C. for 16 hours to give 98-99% conversion to polymer. Weight-averaged T g of this polymer was 60° C. To this was added 16.5 parts of spherical silver particles which had been sieved, selecting particles which passed through a 400-mesh Tyler sieve (38-micrometer openings) and which were held on a 500-mesh sieve (25-micrometer openings). This combination was then knife-coated onto a film of polytetrafluoroethylene as a low adhesion carrier web and was dried for 5 minutes at 100° C. to a dried thickness of 25 micrometers between the silver particles to provide an adhesive transfer tape of the invention. The thickness of its adhesive layer between particles was about 80% of the average diameter of the particles. The adhesive layer was transferred to the back surface of a 75-mm diameter silicon wafer by preheating the wafer on a hot plate to 200° C., positioning the adhesive over the wafer and bringing it into full contact with the wafer by means of a rubber roll. After cooling, the adhesive was trimmed around the wafer circumference, and the release liner and excess adhesive were removed. The wafer was then sawed into individual 1.3 mm×1.3 mm dice after being mounted onto a blue vinyl wafer sawing film (Semiconductor Equipment Corp. Part No. 18074). Individual dice were removed from the wafer sawing film and bonded at 250° C. under a compressive force of 55 newtons to a silver layer on an alumina ceramic substrate. Electrical resistance of the bond between a silicon die and the silver layer was 0.3 ohm as measured by the 4-probe resistance method. The thermal conductivity was 0.017 watts/cm° C. The force required to shear this bond was 46 newtons at ordinary room temperature; 6.7 newtons at 100° C.; and 1.0 newton at 200° C. EXAMPLE 2 An acrylic polymer having a weight-averaged T g of 28° C. was selected and prepared as in Example 1 from the following: ______________________________________ Parts______________________________________methyl methacrylate 6.10methyl acrylate 22.00acrylamide 1.65silane 0.30"Vazo" 64 catalyst 0.05ethyl acetate 70.00______________________________________ To this was added 9 parts of spherical silver particles which had been sieved, selecting particles which passed through a Tyler sieve of 200-mesh (75-micrometer openings) and were held on 325-mesh (45-micrometer openings) followed by flattening in a 3-roll paint mill to a thickness of approximately 40 micrometers. This was knife-coated onto a silicone-surface biaxially-oriented polyethylene terepthalate film and dried 10 minutes at 80° C. to a thickness of about 20 micrometers between the silver particles. The thickness of the adhesive layer between particles was about one-half the average thickness of the particles. The adhesive layer of this transfer tape was transferred to the back of a silicon wafer as in Example 1 except at 150° C. After being sawed into individual dice as in Example 1, each die was bonded onto a silver-coated alumina substrate at 180° C. under a compressive force of 67 newtons. The 4-probe bond resistance measurement indicated a bond resistance of 2.4 ohms between the die and the silver coating. The force required to shear this bond was 17 newtons at ordinary room temperature. EXAMPLE 3 To another portion of the polymer solution of Example 1 was added 8.25 parts spherical silver particles sieved in the same manner as Example 1. This was knife-coated onto a flexible polytetrafluoroethylene film and dried 5 minutes at 100° C. Between particles the dried adhesive layer was 15 micrometers thick or approximately 50% of the average particle diameter. The adhesive layer was transferred at 200° C. to the back of a silicon wafer which was then sawed into 1.3 mm×1.3 mm dice in the same manner as in Example 1. The resistance between a die and the silver layer of the substrate to which it was bonded at 250° C. was 0.6 ohm measured as in Example 1. The force required to shear the bond was 39 newtons at ordinary room temperature. EXAMPLE 4 To another portion of the polymer solution of Example 1 was added 16.5 parts of the flattened silver particles used in Example 2. This was knife-coated onto a a polytetrafluoroethylene film carrier web and dried 10 minutes at 100° C. The adhesive thickness between particles was about 40 micrometers or 75% of the average particle thickness. This adhesive was transferred to the back of a silicon wafer which was then sawed into 1.3 mm×1.3 mm dice in the same manner as in Example 1. When bonded at 250° C. onto a silver-coated alumina substrate, the bond had a resistance of 0.5 ohm and was sheared at a force of 48 newtons at ordinary room temperature.
The adhesive layer of the novel transfer tape contains electrically and thermally conductive particles such as silver which are preferably spherical and are larger than the thickness of the adhesive between particles. When used to bond two rigid substrates together, pressure is applied to the substrates to flatten the particles to the thickness of the adhesive between particles, thus making good electrical and thermal connection between the substrates through each particle.
Concisely explain the essential features and purpose of the invention.
[ "This is a continuation of application Ser.", "No. 503,578, filed June 13, 1983, now abandoned.", "FIELD OF THE INVENTION The invention concerns an adhesive transfer tape which makes electrically and thermally conductive bonds such as are desirable for attaching a semiconductor die or chip to an electrically and thermally conductive substrate, a use previously served primarily by spreadable adhesives or by strips of solder or eutectic alloy.", "BACKGROUND ART Semiconductors such as integrated circuits are formed on wafers which are then cut into dice or chips that individually may be mounted onto substrates.", "Usually the substrate is electrically and thermally conductive, and mounting provides both good electrical and good thermal conductivity between the die and the substrate.", "Good thermal conductivity permits the substrate to serve as a heat sink for the die.", "An effective heat sink is desirable, because as a rule of thumb, an increase of 10° C. in the operating temperature of a semiconductor die reduces its life by one-half.", "Generally the attainment of good thermal conductivity is inherently accompanied by adequate electrical conductivity.", "Of the two prevalent techniques for attaching a semiconductor die to an electrically and thermally conductive substrate, one employs a solder or eutectic alloy such as a gold-silicon alloy.", "While such alloys provide excellent electrical and thermal conductivity, they are exceedingly expensive.", "Also, their application temperatures may be so high that some dice might be damaged, and differences in thermal expansion sometimes cause a die to break.", "Furthermore, it is difficult to handle an individual die together with an alloy strip of the same size.", "Because of the expense and difficulties in using eutectic alloys, it has become more common to employ a spreadable die attach adhesive consisting of a heat-curing epoxy resin composition filled with fine metal particles, usually silver and occasionally gold.", "Spreadable epoxy adhesives can be difficult to use, especially those which are marketed in two parts and must be thoroughly mixed shortly before use.", "Care must be taken to keep the metal particles in suspension, to spread out a uniform layer of the proper thickness, and not to allow voids in the adhesive layer.", "Automated attachment of dice to substrates is complicated by the waiting period during which the epoxy composition is cured.", "DISCLOSURE OF THE INVENTION The above-discussed difficulties of prior die attach systems are avoided in the present invention by an electrically and thermally conductive adhesive transfer tape which is easy to use and reliably attaches individual semiconductor dice to conductive substrates.", "As compared to metal-filled epoxy compositions, the novel adhesive transfer tape should be of comparable cost.", "Briefly, the adhesive transfer tape of the invention comprises a flexible, low-adhesion carrier web to which is lightly adhered a layer of adhesive containing electrically and thermally conductive particles which at the bonding temperature of the adhesive are at least as deformable as are substantially pure silver spherical particles at ordinary room temperature.", "The particles should be of uniform thickness.", "By "uniform"", "is meant that substantially all of the particles (disregarding fines, which are too difficult to eliminate) differ in diameters by no more than 2 to 1.", "The average thickness of the particles is greater than the thickness of the adhesive between particles, preferably from 10 to 100% greater.", "The particles are uniformly distributed throughout the layer or throughout preselected segments of the layer.", "When the particle-containing adhesive layer is removed from the carrier web and compressed between two flat, rigid plates, the particles are flattened to the thickness of the adhesive between particles.", "This provides small, flat conductive areas at both surfaces of the adhesive layer sufficient to provide good electrical and thermal contact between a die and a conductive substrate through each of the flattened particles.", "While being primarily useful as a die attach adhesive tape, the novel transfer tape can be used wherever it is desired to make an electrically conductive bond between two rigid, uniformly spaced surfaces.", "Although such uses may not require good thermal conductivity, this inherently is achieved due to the direct contact of each of the electrically and thermally conductive particles to each of the surfaces which are being bonded together.", "In one such use, the novel tape can be used for surface-mounted components of a printed circuit board.", "For example, a chip carrier having a plurality of conductive pads can be bonded by the novel transfer tape to connect each pad individually to a conductor in the printed circuit board.", "The adhesive layer of the novel tape provides good electrical conductivity through its thickness and good electrical insulation laterally, especially when the particles occupy less than 40% by volume of the adhesive layer.", "To economize the use of the electrically conductive particles, they may be located only in segments of the novel adhesive transfer tape which are to contact individual electrical conductors.", "This can be accomplished by the steps of: (1) coating onto a flexible, low-adhesion carrier web a viscous monomer composition which is radiation-polymerizable to an adhesive state, (2) selectively exposing the coating to radiation to polymerize segments of the monomer composition to a substantially tack-free adhesive state, (3) applying electrically conductive particles to the coating to become adhered only to the viscous monomer composition, and (4) again exposing the coating to radiation to polymerize the balance of the coating to a substantially tack-free adhesive state.", "Because the viscosity of a mixture of polymerizable monomers may be too low to provide desirably thin coatings, the monomers may be partially polymerized to provide a sufficiently viscous monomer composition, e.g., having a coatable viscosity within the range of 1000 to 40,000 cps.", "A second technique for locating electrically conductive particles only in preselected segments of the adhesive layer involves the steps of: (1) coating onto a flexible, low-adhesion carrier web a viscous monomer composition which is radiation-polymerizable to an adhesive state and contains electrically conductive particles, (2) selectively exposing the coating to radiation to polymerize segments of the monomer composition to a solvent-resistant adhesive state, (3) dissolving or otherwise removing portions of the coating between the polymerized adhesive segments, and (4) overcoating the entire segment-containing face of the carrier web with an adhesive such that the total thickness of both adhesive layers between particles is less than the average thickness of the particles.", "The adhesive applied in step (4) can be applied from solution or as a radiation-polymerizable monomer composition.", "A third technique is similar to the second except that instead of steps (1) and (2), an adhesive is applied from solution only onto preselected segments of the low-adhesion carrier, e.g., by silk screening.", "Preferably the adhesive of the novel transfer tape is heat-activatable, i.e., a thermosetting, hot-melt or hot-tackifying adhesive.", "Such adhesives usually are nontacky at ordinary room temperatures and, upon being activated by heat, flow sufficiently under pressure such that the faces of the small, flat conductive areas created at the surfaces of the adhesive layer should be free from adhesive.", "When the novel transfer tape has a heat-activatable adhesive, its low-adhesion carrier web preferably has sufficient resistance to heat to permit the adhesive to be heat-activated while being supported by the carrier web.", "Particularly useful carrier webs are polytetrafluoroethylene and polyimide films, both of which have good heat resistance, strength, dimensional stability, and age resistance.", "Also useful are biaxially-oriented polyethylene terephthalate, aromatic polyimide ("Kevlar"), and polyvinyl fluoride ("Tedlar") films.", "The adhesive layer of the novel adhesive transfer tape preferably is a polymer of alkyl acrylate and/or methacrylate having an average of 1-12 carbon atoms in the alkyl groups.", "Such a polymer provides better adhesion when it is a copolymer of monomers, up to 50 mol % of which is at least one copolymerizable monomer selected from acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, amides of said acids, and N-vinyl-2-pyrrolidone.", "The acids should be minimized or avoided when electrical connections are to be made where corrosion might be a problem.", "Polymers based on alkyl acrylates having an average of 4-12 carbon atoms in their alkyl groups are pressure-sensitive adhesives and may have a weight-averaged T g in the range from -20° to -70° C. When the average is 1-3 or when a polymer is based on an alkyl methacrylate, the copolymer may have a weight-averaged T g in the range from -10° to -80° C. and be nontacky or poorly tacky at ordinary room temperatures, but become aggressively tacky when heated.", "An adhesive which is nontacky at ordinary room temperatures better holds electrically-conductive particles in place after the novel tape has been applied to make electrical connections.", "Hence, those electrical connections tend to be more secure and more resistant to brief exposure to soldering temperatures.", "Where such exposure is contemplated, a weight-averaged T g of from 30° to 80° C. is preferred.", "However, much the same result can be attained by crosslinking a polymer of lower T g after the electrical connections have been made, e.g., as taught in U.S. Pat. No. 2,925,174.", "The particles of the novel tape preferably are substantially spherical, a shape readily deformable to the thickness of the adhesive between particles.", "Preflattened particles such as those of U.S. Pat. No. 3,514,326 (Stow) can also be used but should be made of softer materials because pre-flattened particles are more resistant to further flattening.", "When pre-flattened particles are further flattened, there is a hazard of trapping adhesive between the areas particles and the surface against which they are further flattened.", "Whether pre-flattened or spherical, the particles preferably are made of a metal such as silver or gold or of laminated metals, one of which preferably is at least as deformable at the bonding temperature of the adhesive as is substantially pure silver at ordinary room temperatures.", "When a transfer tape of the invention has a heat-activatable adhesive, its particles may be laminates of materials, one of which melts at the activation temperature of the adhesive.", "Such a laminated particle may have a surface layer that melts and a core that does not melt at the activation temperature of the adhesive, for example, a solder surface layer and either a higher melting metal core such as copper or a nonmetallic core.", "Another useful laminated particle has a surface layer that does not melt and a core that melts at the activation temperature of the adhesive.", "The core of such a particle may be a solder, and its surface layer may be a higher melting metal such as silver or copper.", "Each of the particles of the novel tape may be an aggregate of tiny fused granules such as granules of a metal which is at least as deformable as substantially pure silver.", "Because the heat-activatable adhesive of the novel tape preferably is nontacky at ordinary ambient temperatures, the adhesive layer could be wound directly upon itself for storage and shipment.", "Since it is necessary to form the adhesive layer on a low-adhesion carrier web, it is convenient to wind the two together for storage and shipment.", "A preferred range of thicknesses for the adhesive between particles is from 0.01 to 0.05 mm, and the average particle thickness is preferably between 20 and 80% greater than the adhesive thickness between particles.", "When the particles have highly uniform thicknesses, excellent results are attained at an average particle diameter only 5% greater than the adhesive thickness between particles.", "When the particles comprise 5% by volume of the adhesive layer and their average thickness is one-third greater than the adhesive layer between particles, the average spacing between adjacent particles is about 0.13 mm when the adhesive thickness between particles is 0.02 mm.", "The average spacing may be as great as about 0.5 mm and preferably is within the range of 0.05 to 0.3 mm in order to insure a good overall electrical and thermal conductivity.", "While the novel tape preferably contains electrically and thermally conductive particles, equivalent results can be attained by substituting for the particles other electrically and thermally conductive elements which are as deformable as are the particles under the same conditions to provide small, flat conductive areas at both surfaces of the adhesive layer.", "For example, the electrically and thermally conductive elements may together form a metal foil, the thickness of which is less than that of the adhesive by itself, but which has at each surface of the layer protuberances that are closely spaced and uniformly distributed throughout the layer.", "The average distance between apices of the protuberances at one surface to those at the other surface should be greater than, perferably from 10% to 100% greater than, the thickness of the adhesive between protuberances.", "The protuberances may be provided by embossing the foil as in U.S. Pat. No. 3,497,383 (Olyphant) to form ridges at the surfaces of the adhesive layer that are flattened to provide narrow, elongated flat areas when the adhesive layer is compressed between two flat, rigid plates.", "Each upstanding portion of metal foil extending between an elongated flat area in one surface and the closest flat area in the other surface provides a metal element that conducts heat and electricity across the adhesive layer.", "Alternatively, a metal foil may have additional metal fused to its surfaces.", "For example, drops of silver or of a solder may be fused to a copper foil to provide protuberances, each of which is sufficiently soft to be flattened when the adhesive layer is compressed between two flat, rigid plates.", "The metal foil may have uniformly distributed perforations, in which event the adhesive layer of the novel tape may be continuous.", "When the metal foil is imperforate, the adhesive layer necessarily is separated by the foil into two laminae.", "Useful electrically and thermally conductive elements of the novel tape can also be provided by a wire screen of a conductive material which at the bonding temperature of the adhesive preferably is at least as deformable as is substantially pure silver at ordinary room temperature.", "The pressure applied to such a screen would not only provide small, flat areas on the wires at the surfaces of the adhesive layer but would also flatten the wires at their crossing points, thus enhancing the conductivity of the direct paths between the flattened surface areas.", "The novel adhesive transfer tape may be used as a die attach adhesive as follows.", "First, the tape is adhered by its heat-activated adhesive layer to the back surface of an undiced semiconductor wafer.", "The wafer is then diced while the carrier web serves the function for which wafer sawing films are currently used.", "Each resulting die has its own conductive adhesive layer by which it may be bonded to a conductive substrate after removal of the carrier web.", "If desired, the adhesive-bearing die may be stored indefinitely at room temperature before being adhesively attached to a substrate.", "Preferably the novel adhesive tape is used in connection with a conventional wafer sawing film.", "After bonding the tape by its own heat-activated adhesive tape to a semiconductor wafer and allowing the adhesive to cool, the carrier web is stripped away, and the exposed adhesive layer is adhered to the wafer sawing film by the low-tack adhesive of the wafer sawing film.", "Then while the wafer sawing film is stretched in a hoop fixture, the wafer and adhesive are diced.", "Care should be taken in selecting the wafer sawing film that its low-tack adhesive does not contaminate the adhesive of the novel tape.", "The adhesive layer of the novel tape may be transferred onto an adhesiveless backing of a wafer sawing film which has a low-adhesion surface.", "A semiconductor wafer may be bonded by the adhesive layer to the wafer sawing film and sawed into dice, each thus immediately having an electrically and thermally conductive adhesive layer.", "BRIEF DESCRIPTION OF THE DRAWINGS In the drawings FIG. 1 is a schematic transverse cross-section of a die attach adhesive tape of the invention;", "FIG. 2 is a schematic transverse cross-section showing a semiconductor wafer to which the tape of FIG. 1 has been adhered and in turn mounted on a wafer sawing film for dicing;", "and FIG. 3 shows the use of an adhesive tape similar to that of FIGS. 1 and 2 being used to attach a semiconductor die to a conductive substrate.", "FIG. 4 is a schematic transverse cross-section of another embodiment of the adhesive tape of the invention;", "and FIG. 5 illustrates another schematic transverse cross-section of yet another embodiment of the adhesive tape of the invention.", "DETAILED DESCRIPTION The adhesive tape 10 of FIG. 1 has a flexible carrier web 12 having a low-adhesion surface 14 to which is lightly adhered a layer of adhesive 16 containing spherical electrically and thermally conductive metal particles 18, the diameters of which exceed the thickness of the adhesive 16 between particles.", "In FIG. 2, a piece of tape 10 has been adhered by its layer of adhesive 16 to a semiconductor wafer 20 and the carrier web 12 has been stripped off and discarded.", "The exposed layer of adhesive 16 has been pressed against the low-tack adhesive layer 21 of a conventional wafer sawing film 22 having a carrier web 24.", "While the wafer sawing film is stretched across a hoop fixture (not shown), the wafer 20 and the adhesive layer 16 are sawed at 26.", "Because the adhesive bond between the low-tack adhesive layer 21 and the carrier web 24 is stronger than the bond between the two adhesive layers, each die 20a and its adhesive layer 16a can be lifted off the wafer sawing film 22 and adhesively bonded to a conductive substrate to provide a composite similar to that illustrated in FIG. 3. FIG. 3 shows a die 30 which is bonded to an electrically and thermally conductive substrate 32 by a layer of heat-activated adhesive 34 containing electrically and thermally conductive laminated particles 36.", "Each of those particles has been flattened by pressing the die 30 against the substrate 32, and that part of the adhesive 34 which had covered the particles has been forced out from between the particles and the substrate 32, thus providing small, flat conductive areas at each surface of the layer of adhesive 34.", "Each particle 36 has a core 39 and a surface layer 38, one of which may have melted while the other did not melt at the temperature at which the adhesive 34 was activated.", "FIG. 4 illustrates another embodiment of the invention wherein adhesive tape 40 is illustrated containing wire screen 41 of a conductive material and adhesive 16.", "FIG. 5 illustrates adhesive tape 50 with embossed foil 51 and adhesive 16.", "In the following examples, all parts are given by weight unless otherwise noted.", "EXAMPLE 1 An acrylic polymer was made by mixing together 15.5 parts ethyl acrylate, 15.5 parts methyl acrylate, 1.65 parts acrylamide, 0.3 part gamma-methacryloxypropyltrimethoxysilane, 67 parts ethyl acetate and 0.1 part azo-bis-isobutylnitrile ("Vazo"", "64 catalyst), purging the mixture with nitrogen to remove oxygen, and heating at 53°-55° C. for 16 hours to give 98-99% conversion to polymer.", "Weight-averaged T g of this polymer was 60° C. To this was added 16.5 parts of spherical silver particles which had been sieved, selecting particles which passed through a 400-mesh Tyler sieve (38-micrometer openings) and which were held on a 500-mesh sieve (25-micrometer openings).", "This combination was then knife-coated onto a film of polytetrafluoroethylene as a low adhesion carrier web and was dried for 5 minutes at 100° C. to a dried thickness of 25 micrometers between the silver particles to provide an adhesive transfer tape of the invention.", "The thickness of its adhesive layer between particles was about 80% of the average diameter of the particles.", "The adhesive layer was transferred to the back surface of a 75-mm diameter silicon wafer by preheating the wafer on a hot plate to 200° C., positioning the adhesive over the wafer and bringing it into full contact with the wafer by means of a rubber roll.", "After cooling, the adhesive was trimmed around the wafer circumference, and the release liner and excess adhesive were removed.", "The wafer was then sawed into individual 1.3 mm×1.3 mm dice after being mounted onto a blue vinyl wafer sawing film (Semiconductor Equipment Corp.", "Part No. 18074).", "Individual dice were removed from the wafer sawing film and bonded at 250° C. under a compressive force of 55 newtons to a silver layer on an alumina ceramic substrate.", "Electrical resistance of the bond between a silicon die and the silver layer was 0.3 ohm as measured by the 4-probe resistance method.", "The thermal conductivity was 0.017 watts/cm° C. The force required to shear this bond was 46 newtons at ordinary room temperature;", "6.7 newtons at 100° C.;", "and 1.0 newton at 200° C. EXAMPLE 2 An acrylic polymer having a weight-averaged T g of 28° C. was selected and prepared as in Example 1 from the following: ______________________________________ Parts______________________________________methyl methacrylate 6.10methyl acrylate 22.00acrylamide 1.65silane 0.30"Vazo"", "64 catalyst 0.05ethyl acetate 70.00______________________________________ To this was added 9 parts of spherical silver particles which had been sieved, selecting particles which passed through a Tyler sieve of 200-mesh (75-micrometer openings) and were held on 325-mesh (45-micrometer openings) followed by flattening in a 3-roll paint mill to a thickness of approximately 40 micrometers.", "This was knife-coated onto a silicone-surface biaxially-oriented polyethylene terepthalate film and dried 10 minutes at 80° C. to a thickness of about 20 micrometers between the silver particles.", "The thickness of the adhesive layer between particles was about one-half the average thickness of the particles.", "The adhesive layer of this transfer tape was transferred to the back of a silicon wafer as in Example 1 except at 150° C. After being sawed into individual dice as in Example 1, each die was bonded onto a silver-coated alumina substrate at 180° C. under a compressive force of 67 newtons.", "The 4-probe bond resistance measurement indicated a bond resistance of 2.4 ohms between the die and the silver coating.", "The force required to shear this bond was 17 newtons at ordinary room temperature.", "EXAMPLE 3 To another portion of the polymer solution of Example 1 was added 8.25 parts spherical silver particles sieved in the same manner as Example 1.", "This was knife-coated onto a flexible polytetrafluoroethylene film and dried 5 minutes at 100° C. Between particles the dried adhesive layer was 15 micrometers thick or approximately 50% of the average particle diameter.", "The adhesive layer was transferred at 200° C. to the back of a silicon wafer which was then sawed into 1.3 mm×1.3 mm dice in the same manner as in Example 1.", "The resistance between a die and the silver layer of the substrate to which it was bonded at 250° C. was 0.6 ohm measured as in Example 1.", "The force required to shear the bond was 39 newtons at ordinary room temperature.", "EXAMPLE 4 To another portion of the polymer solution of Example 1 was added 16.5 parts of the flattened silver particles used in Example 2.", "This was knife-coated onto a a polytetrafluoroethylene film carrier web and dried 10 minutes at 100° C. The adhesive thickness between particles was about 40 micrometers or 75% of the average particle thickness.", "This adhesive was transferred to the back of a silicon wafer which was then sawed into 1.3 mm×1.3 mm dice in the same manner as in Example 1.", "When bonded at 250° C. onto a silver-coated alumina substrate, the bond had a resistance of 0.5 ohm and was sheared at a force of 48 newtons at ordinary room temperature." ]
BACKGROUND OF THE INVENTION The present invention relates to a manually operated switch such as a wall-mounted light switch for controlling the level of light intensity from a light fixture and more particularly to a light level controller actuated by the switch which includes a microcomputer for initiating control programs to regulate the level of light intensity. Wall-mounted light switches which include a dimmer have become increasingly popular especially for residential applications where it is desired to precisely control the level of light intensity in a particular room. Such light switches usually include a variable resistor which is manually manipulated to control the voltage input to the light, where the variable resistor is connected in series with the household AC power line. A desirable feature in such switches would be the ability to return to predetermined levels of light intensity from conditions of either full power on or full power off. At present, however, such switches have no such memory and formerly established light intensity levels may be reestablished only by manual operation and guesswork. There are in existence, however, touch actuated dimmer controls which cycle through a dim to a bright cycle and back again, and include a memory function such that removing the hand from the switch will stop the cycle and store the level of light intensity at that point in memory. A subsequent touch will turn the light off and yet a further touch will return the light to its previous intensity level based upon the value of the intensity level stored in memory. While an improvement over the manually-operated variable-resistor type of dimmer, this dimmer may require the user to manually cycle through a complete cycle of dim light to bright light to arrive at a desired intensity level. This latter switch is known as a DECORA® touch dimmer and is manufactured by Leviton Manufacturing Company, Inc. of Littleneck, N.Y. The DECORA® touch dimmer, however, lacks the versatility needed for certain aesthetic effects such as an automatic gradual fade from one light level to another. Moreover, it cannot change the direction, that is, either the increasing (up) or the decreasing (down), of light intensity from one direction to another without completing a full cycle from dim to bright and back again. Also, the touch dimmer has no "remote" capability that would enable one to use its features from a remote location such as a hallway or another room. Full function remotes are common with ordinary two-position light switches, but have not been available for dimmers because of the complexity of the circuitry. Yet another touch-type light control is shown in Hamilton, U.S. Pat. No. 3,805,096, and in Hosaka, et al., U.S. Pat. No. 4,359,670. These devices are responsive to the duration of touch for initiating various control functions but include no provision for automatically fading light from one level to another. Automatic fading has in the past been available only in theatrical lighting systems employing very complicated switching inputs such as keyboard commands or elaborate banks of switches. Examples of such systems are shown in Williams, U.S. Pat. No. 4,241,295; Dinges, et al., U.S. Pat. No. 4,240,011; Van Buren, U.S. Pat. No. 3,706,914; and Isaacs, U.S. Pat. Nos. 3,766,431 and 3,668,467. SUMMARY OF THE INVENTION The present invention provides a highly versatile microcomputer-controlled light level intensity switch which is operated by a pair of non-latching switches which provide inputs to the microcomputer. The non-latching switches may be arranged as upper and lower switches on a rocker panel or independent pair of panels which are normally biased to remain in a neutral position. The switches are each connected in series with the AC mains power line so that when either switch is depressed a signal in the form of a series of sequential pulses is provided to the microcomputer. When the switch is depressed in either the up or down direction, the microcomputer first determines whether the depression of the switch is momentary, that is, a brief tap, or whether it is being held down for a period of more than transitory duration. When the switch is held, the microcomputer advances the level of light intensity in the direction indicated by the switch, that is, either towards bright or towards dim. When the switch is subsequently released the microcomputer stores that current level of light intensity as a "preset" level in its memory. If the switch is first tapped in either direction with the light intensity at some static level the microcomputer will cause the level of light intensity to automatically advance or "fade" towards a predetermined level, either "full on," "off," or "preset." The fade may occur at a rate which can be programmed in the microcomputer. If desired, the speed of the fade may vary depending upon whether the fade is from dim to bright or vice versa. For example, it is possible to program all downward fades to occur more gradually than all upward fades. If the switch is tapped again while the light intensity is fading towards the preset level, the microcomputer will halt the fade and cause the light intensity level to abruptly shift to the preset level. If the "up" switch is tapped with light at the preset level, the light intensity will fade to full maximum. If it is tapped in the downward position when the light intensity level is at the preset position the light intensity will fade towards zero. Thus, the microcomputer interprets the character of the command, that is, a hold or a tap, determines the current control mode, and initiates a light intensity control function accordingly. The three types of programs are preset, automatic fade, and abrupt transition. The non-latching switches provide a pulse input, which is derived from the AC power source, to the light switch through a clamp and half-wave rectifying network. Thus, the input to the microcomputer is a series of square wave pulses. The microcomputer has an internal program which counts the number of a sequential series of pulses to determine if the switch is being tapped or held and executes a control program mode accordingly. The microcomputer is connected to a source of light such as an incandescent light bulb of between 40 and 2,000 watts by means of a thyristor solid state switch. The thyristor controls power to the incandescent light source by turning on at a predetermined phase angle relative to the phase of the AC line source. For this purpose the thyristor is responsive to a timed firing signal generated by the microcomputer according to the program in operation. The firing signal is synchronized with the incoming power supply line by a zero crossing detector which detects the transition in the AC power line from positive to negative. The microcomputer receives the zero crossing information and synchronizes this information with its internal clock which controls the timing of the firing signal for the thyristor. In this way the timing of the thyristor firing signal is calibrated to the desired level of light intensity and represents a phase angle at which the AC line is gated into the incandescent light source. When either the "up" or "down" switch is held the computer first determines the current level of light intensity. The microcomputer then causes the level of light intensity to increase for "up" or decrease for "down" in predetermined increments by initiating thyristor firing signals which either advance the phase gating of the AC wave or retard it. As long as either switch is held "on," the level of light intensity will gradually advance or decline. Each time an additional increment of light intensity is added it replaces the current level in the memory which continues to be sampled in a closed-loop fashion until the switch is released. When the switch is released the current level of light intensity is stored in memory as a "preset" level. When either switch is tapped the microcomputer interrogates memory to find out if the current level is equal to the preset level. This determines whether a fade is in progress or whether the light intensity is not changing. The subsequent control modes, "fade" and "abrupt transition," then depend upon whether the new level in memory is preset, full on, or full off, and whether the current level is higher than, lower than, or equal to this level. The switches are wired in line with the main 120-volt AC line. Since the switches are at all times either "on" or "off" and there are no variable resistors used for the dimming function, a parallel set of remote switches, also wired in line with the AC line, may be provided to give full remote capability. Thus, another switch box may be provided in a hallway or adjacent room which fully duplicates the functions of the primary switch box without the necessity for duplication of the microcomputer and its associated circuitry. The remote switches are wired in parallel with the primary switches through their wall-mounted switch box forming a second parallel input to the microcomputer. A primary object of this invention is to provide a light level controller which provides a maximum degree of flexibility in altering levels of light intensity according to the desires of the user. A further object of this invention is to provide a light level controller which includes an automatic fader for gradually fading the light intensity level from a current level to a preset level. Yet a further object of this invention is to provide a light level controller having means for manually overriding the automatic fader and for making abrupt transitions in light level intensity from a current level to a predetermined level. A still further object of this invention is to provide a light level controller having the above features which can be mounted within a standard wall switch panel box and connected to a standard 60-cycle AC household power supply. Yet a further of this invention is to provide a light level controller in a wall switch mounting which is microcomputer-controlled and responsive to the state of non-latching switches which provide a digital input signal to the microcomputer. A still further object of this invention is to provide a light level controller having a plurality of light control modes in which the particular mode chosen is a function of the period of time that the non-latching control switch is pressed. A further object of this invention is to provide a light level controller in a wall switch mounting having a visual indication of the intensity of the light on the room. A still further object of this invention is to provide a wall-mounted light level controller having full remote capability. The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideraton of the following detailed description of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of a circuit constructed according to the present invention. FIG. 2 is a side view of a wall switch mounting containing the circuit of the present invention illustrated in FIG. 1. FIG. 3 is a front view of an alternate type of wall switch mounting. FIG. 3(a) is a side view of the wall switch mounting of FIG. 3. FIG. 4 is a flow chart diagram depicting the method of operation of the circuit illustrated in FIG. 1. FIG. 4(a) is a continuation of a portion of the flow chart diagram of FIG. 4. FIG. 4(b) is a further continuation of the flow chart diagram of FIG. 4. FIG. 5 is a waveform diagram illustrating the method of controlling the line voltage input to a light source using the circuit of FIG. 1 DETAILED DESCRIPTION OF THE INVENTION A light source 10 which may be, for example, an incandescent light source drawing between 40 and 2,000 watts of power, is connected to a source of AC power 12 through a thyristor 14. The AC source 12 is a standard household power supply, 60-cycle, 120-volt AC. The thyristor 14 is a bi-directional SCR controller. The control line 11 for the thyristor 14 is connected to a microcomputer 16. The microcomputer 16 is powered by a DC power supply 18 and includes an input from a zero crossing detector 20 which is also connected to AC power source 12. A wall switch mounting 22 (enclosed within the dotted line in FIG. 1) may include a pair of nonlatching switches 24a and 24b and an LED display 26. The LED display may be connected to the microcomputer 16 by a bus 28 which may include any desired plurality of lines. In the example shown in FIG. 1, line 28 is an eight line bus. Each of the nonlatching switches 24a and 24b includes a rectifier and clamp circuit 30a and 30b, respectively, which provide half-wave rectification and voltage clamping. The switches 24a and 24b are connected to AC power source 12 through a resistor 17 and diodes 13 and 15. The output of the rectifier and clamp circuits 30a and 30b are connected as inputs to microcomputer 16. Microcomputer 16 also includes a clock which may, for example, be a crystal oscillator 32. The microcomputer 16 also includes as an input, a reset network 34. A remote input 19 may also be provided as a parallel input to circuts 30a and 30b. Remote input 19 is in all respects identical to the network of switches 24a and 24b including resistor 17 connected to the AC line and diodes 13 and 15. Thus, either the wall mounting 22 or the remote input 19 may initiate the functions discussed herein. Between thyristor 14 and light source 10 there is a choke or induction coil 36 which provides current damping for the light source 10. Without such a choke 36 the filament in an incandescent light source such as light source 10 may physically oscillate under certain conditions. Thyristor 14 has an output comprising AC pulses having relatively fast rise times. The choke 36 smooths the shape of these pulses so that there is no ringing or spurious oscillation within the light source 10. The input of the microcomputer 16 from the rectifier and clamp circuits 30a and 30b is responsive to a series of sequential square wave pulses. These pulses are developed from the line inputs through either switch 24a or 24b. For example, if switch 24a is depressed the line voltage is fed to rectifier and clamp circuit 30a which provides half-wave rectification and clamps the voltage peaks to a level compatible with the microcomputer inputs, that is approximately 5 volts. The switches 24a and 24b are arranged to provide "up" and "down" light level changes, respectively. A detailed functional description of the consequence of pressing either switch will be explained below, but, in general, switch 24a increases the brightness level of the light source 10 and may therefore be considered an "up" switch and switch 24b decreases the brightness level of the light source 10 and may therefore be considered a "down" switch. Accordingly, rectifier and clamp circuit 30b provides negative-going square wave pulses as an input to microcomputer 16 and the circuit 30a provides positive-going square wave pulses. The reset network 34 provides a signal that resets the microcomputer 16 upon initial power up of the system irrespective of fluctuation in the DC power supply 18. Such circuits are well known in the electronics art. The zero crossing detector 20 determines the zero crossing points of the input power AC waveform from AC power source 12. This information is synchronized with the crystal oscillator 32 so that the thyristor 14 may be controlled by gating voltage from the AC power source 12 into the light source 10 at predetermined times relative to the zero crossing points. Microcomputer 16 is a single chip microcontroller which may include read only memory and random access memory. Such a microcontroller is manufactured by National Semiconductor Co. and bears the model number COP413L. The microcomputer 16 receives commands from the rectifier and clamp circuits 30a and 30b, and synchronizes those commands with the zero crossing points of the AC power line by way of a signal from zero crossing detector 20, and provides appropriate firing commands to thyristor 14 over line 11. The programs executed by microcomputer 16 and the method of operating switches 24a and 24b to achieve the programmed results will be explained below. Referring now to the flow chart diagrams of FIGS. 4, 4(a) and 4(b), there are four possible switch conditions for switches 24a and 24b. These are identified as the decision nodes "up held", "down held", "up valid", and "down valid". There also exists the possibility that none of the four above conditions exists and the light will remain at its current level by the continuous completing of the zero crossing ("Z.C.") subroutine, shown in the bottom half of FIG. 4, once every 1/120 second. This subroutine is responsible for generating a firing or command signal over line 11 which controls the phase angle at which the triac fires during each 1/2 cycle of the 60 cycle AC power input. If desired, the Z.C. subroutine may be executed every other half cycle or every third half cycle. Thus an instruction could be provided in the program to skip a certain number of half cycles before executing the Z.C. subroutine. The effect of such a instruction would be to provide a more gradual automatic fade or preset. The first step in the zero crossing subroutine is to determine if the current intensity level "C" equals a new or desired intensity level. The new level, indicated by the letter "N," may have one of three values. It may be equal to the "preset" level "full on" or "full off." Thus, in a case where N is equal to C, which would be the case if none of the switch conditions identified in the four decision nodes above currently existed, the microcomputer 16 would determine the time of zero crossing of the AC input wave with reference to its own internal clock. As soon as it is determined that a zero crossing has occurred the microcomputer 16 begins counting until it reaches a point in time in the current half-cycle of the AC wave at which the voltage input will cause the light 10 to have the desired level of light intensity N (FIG. 5). This point in time may be expressed as a phase angle of the line input wave. At the predetermined phase angle the microcomputer will initiate a firing signal which will cause the thyristor 14 to gate the remaining portion of the AC voltage wave into the light source 10. The resultant voltage input which is shown as the "load voltage" line in FIG. 5 is a sharply rising pulse whose power content represents a fraction of the total available AC power line output. The sharply rising input wave form is smoothed by choke 36 to eliminate ringing or oscillation of the filament in the light source 10. The thyristor 14 is fired once each half cycle and after each firing the microcomputer 16 interrogates the inputs from circuits 30a and 30b to determine the status of switches 24a and 24b. The interrogation sequence and the resulting computations to determine the proper light level occur during a brief period of time at the beginning and at the end of each half cycle of the input waveform as indicated by the shaded portions under the curve of the input wave in FIG. 5. During these periods no firing signal is generated and the thyristor 14 remains off. These are the points in the cycle, however, when the input voltage is lowest and the effect upon power availability is therefore negligible. The microcomputer 16 determines the status of the switches 24a and 24b based upon the number of sequential square wave pulses counted at each of the switch inputs from circuits 30a and 30b during each sampling period. Depressing either of the switches 24a or 24b will cause circuit 30a or 30b to generate a series of square wave pulses for as long as the switch is depressed. Thus, the number of sequential pulses received is a function of the length of time that the user manually depresses the panel (refer to FIGS. 2 and 3) that actuates the switches 24a and 24b. The microcomputer 16 counts the number of pulses in order to discriminate between a "hold" condition and a "tap" condition. If the microcomputer 16 reads a predetermined number of pulses "n" when it interrogates a switch input it may interpret the condition as a hold, and if it receives a number of pulses greater than a predetermined minimum "m" but less than n it may interpret the switch condition as a "tap." The predetermined minimum is necessary so that the micro-computer will not interpret spurious noise as a valid switch condition. Referring again to the top of FIG. 4, if n pulses are counted while the input from rectifying and clamp circuit 30a is being sampled the microcomputer 16 determines that the up switch is being held. It then determines whether the current level of light C is at full power or less than full power. If the current level of light C is less than full the microcomputer increments C and simultaneously makes the new level just achieved equal to C and the preset level P equal to C. The zero crossing subroutine is then executed. The result of this loop is that as long as the user continues to depress switch 24a, the microcomputer 16 will cause C to increment one step at a time per half cycle until the switch is released. If switch 24b remains depressed the microcomputer 16 will decrement C simultaneously making N equal to C and P equal to C until the light is either fully off or until the user releases the button controlling switch 24b. The operations N=C and P=C are also memory operations and values of N and P are stored in memory for subsequent operations. The above described loops represent the preset mode of light control and serve to establish a new value in memory for a level of light intensity P at the same time that a new level of light intensity is being established in the light source 10 through the zero crossing subroutine. If during a sampling period the microcomputer 16 discovers a "tap" condition on the "up" switch 24a, it executes the computational routine shown in FIG. 4(a). First the microcomputer 16 determines if the current level of light intensity equals the new or desired level of light intensity N. N could be the preset level stored in memory or could be a level corresponding to full power on. If C=N, the microcomputer 16 then determines whether C=full power. If yes, the zero crossing subroutine is executed. If no, microcomputer 16 determines if N is then equal to P. If yes, the microcomputer makes N equal to full power and executes the zero crossing subroutine. If no, the microcomputer 16 makes N equal to P and executes the zero crossing subroutine. When N=P or N=full and the zero crossing subroutine is executed, N will not be equal to C and therefore the command "move C one towards N" in the zero crossing subroutine will be executed. Since the computational routine in FIG. 4(a) established N as a value which was not equal to the current value C of the light intensity level, the zero crossing subroutine will repeat itself until N=C (assuming no switches have been depressed in the meantime), at which time the level of light intensity will remain constant at the new level N. Thus, when N does not equal C in the zero crossing subroutine, an automatic fade mode is initiated which moves C one incremental value towards N each time the loop is repeated. This loop is executed a chosen number of times a second and by choosing that number or the magnitude of the incremental steps through which N moves, the designer may regulate the slope of the automatic fade mode. For example, if the increments of N are made very small it would take the completion of more loops to move C to the value of N (a slower fade) than it would if the incremental values of C were made larger (a faster fade). According to the preferred embodiment, each half cycle is divided into 160 incremental steps and the Z.C. subroutine is executed every third half cycle. This results in a fade in which the incremental increases or decreases in light intensity are imperceptible and the fade appears to be smooth and continuous. If the up button is tapped while the automatic fade mode is in operation, a different set of conditions will exist at the first decision node in FIG. 4(a). In this case C will not be equal to N because N=P≠C and the microcomputer 16 will be in the process of fading C towards N. In such a case the microcomputer first determines if N is greater than or less than C. If N is greater than C, C is assigned a value that is equal to N. This causes the level of light intensity to abruptly jump from C to N. When the zero crossing subroutine is executed N will then be equal to C and the automatic fade mode will be circumvented as shown in FIG. 4. Thus, the difference between a fade and an abrupt transition lies in making C either equal to a new or desired level N or in making C equal to some value that is not N prior to execution of the zero crossing subroutine. For example, if N is not greater than C in FIG. 4(a), microcomputer 16 makes N equal to P, a preset level which is lower than C. Since N is then not equal to C at the commencement of the zero crossing subroutine, C moves one step at a time towards N which is lower than C, and a downward automatic fade is commenced. The operation of the switch when the down button is tapped is similar in operation to the situation encountered when the up button is tapped. If no fade is in progress when the down button is tapped, C will be equal to N. Subsequently, N will be made equal to zero and the zero crossing subroutine will cause the light intensity level to fade to off. If a fade is in progress such that when the down button is tapped, N is either equal to, greater than, or less than C, the light either fades to off or makes an abrupt transition to off. A delay mode may be provided when a down fade is in progress to make downward fading more gradual than upward fading. Thus, if during a Z.C. subroutine a downward fade is detected, the microcomputer 16 delays the thyristor firing until the delay subroutine has been completed, incrementing the delay function one step at a time until its completion. If the down button is pressed while an up fade is in progress, N is made equal to zero and C fades toward N in the zero crossing subroutine. If the down is pushed while the system is fading towards off, N will be less than C and microcomputer 16 will make C equal to N which will cause the auto-fade mode in the zero crossing subroutine to be circumvented and the light will make an abrupt transition to off. Physically the system represented in the block diagram of FIG. 1 may be enclosed in a wall mounted light switch. One example of such a switch is shown in the side view of the switch in FIG. 2. The switch of FIG. 2 includes a cover plate 38 and a rectangular bezel 40. The bezel 40 encloses a rocker mounted panel 42 which includes two inwardly extending fingers 44a and 44b. The fingers 44a and 44b are adapted to make contact with non-latching push buttons 46a and 46b. The push buttons 46a and 46b are mounted on a PC board 48 which also includes the circuit elements shown in the block diagram of FIG. 1 with the exception of the incandescent light source 10 and the AC power supply 12. The PC board 48 is mounted to an aluminum heat sink 50. An air gap safety switch 52 is also mounted to the heat sink which breaks the circuit when slider 67 is actuated. The switch components are enclosed in a box 54 of a size compatible with the current size standards for wall-mounted light switch boxes. Inside the box 54 is choke coil 36. An aperture 56 in box 54 provides a means for connection to the incandescent light source 10 by way of wire 58. The rocker panel 42 includes apertures 60 (only one such aperture is shown in FIG. 2) in which are mounted light-emitting diodes (LEDs) such as LED 62. LED 62 is part of LED display 26 identified in FIG. 1. There may be as many LEDs as desired. According to the preferred embodiment there should be eight because the National Semiconductor chip used for microcomputer 16 has eight outputs which may be arranged to provide a signal indicating the current level of light intensity. For example, the LEDs may be arranged in an array extending along the rocker panel 42 from top to bottom so that the vertical position in the array of the LED that is on indicates the level of brightness. The nonlatching push buttons 46a and 46b correspond functionally to switches 24a and 24b in FIG. 1. Thus, depressing the upper portion of the rocker panel 42 will cause finger 44a to engage push button 46a and close the "up" switch 24a. Similarly, pressing the lower half of rocker panel 42 will close "down" switch 24b. The rocker panel 42 is biased by a pair of angled legs 64a and 64b that fit snugly within an aperture in heat sink 50. The legs 64a and 64b cause the fingers 44a and 44b to release the push buttons 46a and 46b when there is no manual pressure on either half on the rocker panel 42. An alternative embodiment of the wall mounting for FIG. 2 is shown in FIGS. 3 and 3a. The wall mounting of FIG. 3 includes a cover plate 66 and a two push plates 68a and 68b. LEDs 62 are arranged vertically from top to bottom through apertures in plates 68a and 68b, respectively. Each of the push plates 68a and 68b include inwardly protruding fingers 70a and 70b which engage pushbuttons 72a and 72b which are similar in all respects to pushbuttons 46a and 46b. The plates 68a and 68b are biased by a biasing means such as a spring (not shown). The electrical components of FIG. 1 are housed within a box 74 in a way similar to that depicted in FIG. 2. Although non-latching switches are preferred, a center-off toggle switch (i.e., standard wall-mounted switch) could be used. The user must simply momentarily depress the switch in either direction and return it to center for a "tap" and hold it longer for a "hold." In actual operation, pushing the up panel 68a or the upper half of rocker switch 42 when the light is off will cause the level of light intensity to rise and fade gradually towards the preset level. If the fade is in progress, tapping panel 68a or rocking switch 42 in the up position will cause the light to make an abrupt transition to the preset level. If up is pressed while the light is at the preset level the light will fade to a full power condition and if up is pressed while the light is fading to a full up condition the light will make an abrupt transition to full power. If down switch 68b or the lower half of rocker panel 42 is depressed, indicating a down switch condition, the light will fade towards off or zero. If down is pushed while a down fade is in progress, the light will make an abrupt transition to off. If, on the other hand, the up switch panel 68a or the upper portion of rocker panel 42 is pushed while a down fade is in progress, the light will fade to the preset level. Whenever panel 68a or 68b is held in one position for a period of more than transitory duration, the light level will move up or down stopping only when the panel is released. Simultaneously, the microcomputer 16 will store that current level of light intensity in memory as the preset level P. This preset remains in memory until a subsequent holding of either of the switches to establish a new level. If desired, the switching function may be divided between "tap" and "hold" and a second set of switches may be provided to take over one of the above functions. For example, a rocker panel could be dedicated to upward and downward taps and a second panel or toggle could provide the hold function for preset. Moreover, it is not necessary that the tap or hold functions depend on the time duration of the depression of the switches. If two sets of switches are used, the microcomputer 16 may be programmed to accept one set of switches at one input pin as the tap input and the second set as the hold, or preset, input on another pin regardless of length of time that either is held down. The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.
A light level controller includes a microcomputer controlled light switch which responds to a manual tap or a longer manual depression of the switch in order to initiate various control modes for a light source. Preset levels of light intensity may be stored in the microcomputer's memory and an automatic fade mode may be initiated to cause the level of light intensity to fade from a current level to a preset level at a pre-established rate. The controller may respond to the momentary depression of the switch to initiate the automatic fade mode or if tapped while a fade is in progress it may cause the light source to make an abrupt transition to either full on or full off, depending on whether a higher or lower level of light intensity is desired. A depression of the switch for a period longer than a tap will cause the level of light intensity to continue to change until the switch is released, and simultaneously this level will be stored in memory.
Briefly summarize the main idea's components and working principles as described in the context.
[ "BACKGROUND OF THE INVENTION The present invention relates to a manually operated switch such as a wall-mounted light switch for controlling the level of light intensity from a light fixture and more particularly to a light level controller actuated by the switch which includes a microcomputer for initiating control programs to regulate the level of light intensity.", "Wall-mounted light switches which include a dimmer have become increasingly popular especially for residential applications where it is desired to precisely control the level of light intensity in a particular room.", "Such light switches usually include a variable resistor which is manually manipulated to control the voltage input to the light, where the variable resistor is connected in series with the household AC power line.", "A desirable feature in such switches would be the ability to return to predetermined levels of light intensity from conditions of either full power on or full power off.", "At present, however, such switches have no such memory and formerly established light intensity levels may be reestablished only by manual operation and guesswork.", "There are in existence, however, touch actuated dimmer controls which cycle through a dim to a bright cycle and back again, and include a memory function such that removing the hand from the switch will stop the cycle and store the level of light intensity at that point in memory.", "A subsequent touch will turn the light off and yet a further touch will return the light to its previous intensity level based upon the value of the intensity level stored in memory.", "While an improvement over the manually-operated variable-resistor type of dimmer, this dimmer may require the user to manually cycle through a complete cycle of dim light to bright light to arrive at a desired intensity level.", "This latter switch is known as a DECORA® touch dimmer and is manufactured by Leviton Manufacturing Company, Inc. of Littleneck, N.Y. The DECORA® touch dimmer, however, lacks the versatility needed for certain aesthetic effects such as an automatic gradual fade from one light level to another.", "Moreover, it cannot change the direction, that is, either the increasing (up) or the decreasing (down), of light intensity from one direction to another without completing a full cycle from dim to bright and back again.", "Also, the touch dimmer has no "remote"", "capability that would enable one to use its features from a remote location such as a hallway or another room.", "Full function remotes are common with ordinary two-position light switches, but have not been available for dimmers because of the complexity of the circuitry.", "Yet another touch-type light control is shown in Hamilton, U.S. Pat. No. 3,805,096, and in Hosaka, et al.", ", U.S. Pat. No. 4,359,670.", "These devices are responsive to the duration of touch for initiating various control functions but include no provision for automatically fading light from one level to another.", "Automatic fading has in the past been available only in theatrical lighting systems employing very complicated switching inputs such as keyboard commands or elaborate banks of switches.", "Examples of such systems are shown in Williams, U.S. Pat. No. 4,241,295;", "Dinges, et al.", ", U.S. Pat. No. 4,240,011;", "Van Buren, U.S. Pat. No. 3,706,914;", "and Isaacs, U.S. Pat. Nos. 3,766,431 and 3,668,467.", "SUMMARY OF THE INVENTION The present invention provides a highly versatile microcomputer-controlled light level intensity switch which is operated by a pair of non-latching switches which provide inputs to the microcomputer.", "The non-latching switches may be arranged as upper and lower switches on a rocker panel or independent pair of panels which are normally biased to remain in a neutral position.", "The switches are each connected in series with the AC mains power line so that when either switch is depressed a signal in the form of a series of sequential pulses is provided to the microcomputer.", "When the switch is depressed in either the up or down direction, the microcomputer first determines whether the depression of the switch is momentary, that is, a brief tap, or whether it is being held down for a period of more than transitory duration.", "When the switch is held, the microcomputer advances the level of light intensity in the direction indicated by the switch, that is, either towards bright or towards dim.", "When the switch is subsequently released the microcomputer stores that current level of light intensity as a "preset"", "level in its memory.", "If the switch is first tapped in either direction with the light intensity at some static level the microcomputer will cause the level of light intensity to automatically advance or "fade"", "towards a predetermined level, either "full on,"", ""off,"", "or "preset.", """, "The fade may occur at a rate which can be programmed in the microcomputer.", "If desired, the speed of the fade may vary depending upon whether the fade is from dim to bright or vice versa.", "For example, it is possible to program all downward fades to occur more gradually than all upward fades.", "If the switch is tapped again while the light intensity is fading towards the preset level, the microcomputer will halt the fade and cause the light intensity level to abruptly shift to the preset level.", "If the "up"", "switch is tapped with light at the preset level, the light intensity will fade to full maximum.", "If it is tapped in the downward position when the light intensity level is at the preset position the light intensity will fade towards zero.", "Thus, the microcomputer interprets the character of the command, that is, a hold or a tap, determines the current control mode, and initiates a light intensity control function accordingly.", "The three types of programs are preset, automatic fade, and abrupt transition.", "The non-latching switches provide a pulse input, which is derived from the AC power source, to the light switch through a clamp and half-wave rectifying network.", "Thus, the input to the microcomputer is a series of square wave pulses.", "The microcomputer has an internal program which counts the number of a sequential series of pulses to determine if the switch is being tapped or held and executes a control program mode accordingly.", "The microcomputer is connected to a source of light such as an incandescent light bulb of between 40 and 2,000 watts by means of a thyristor solid state switch.", "The thyristor controls power to the incandescent light source by turning on at a predetermined phase angle relative to the phase of the AC line source.", "For this purpose the thyristor is responsive to a timed firing signal generated by the microcomputer according to the program in operation.", "The firing signal is synchronized with the incoming power supply line by a zero crossing detector which detects the transition in the AC power line from positive to negative.", "The microcomputer receives the zero crossing information and synchronizes this information with its internal clock which controls the timing of the firing signal for the thyristor.", "In this way the timing of the thyristor firing signal is calibrated to the desired level of light intensity and represents a phase angle at which the AC line is gated into the incandescent light source.", "When either the "up"", "or "down"", "switch is held the computer first determines the current level of light intensity.", "The microcomputer then causes the level of light intensity to increase for "up"", "or decrease for "down"", "in predetermined increments by initiating thyristor firing signals which either advance the phase gating of the AC wave or retard it.", "As long as either switch is held "on,"", "the level of light intensity will gradually advance or decline.", "Each time an additional increment of light intensity is added it replaces the current level in the memory which continues to be sampled in a closed-loop fashion until the switch is released.", "When the switch is released the current level of light intensity is stored in memory as a "preset"", "level.", "When either switch is tapped the microcomputer interrogates memory to find out if the current level is equal to the preset level.", "This determines whether a fade is in progress or whether the light intensity is not changing.", "The subsequent control modes, "fade"", "and "abrupt transition,"", "then depend upon whether the new level in memory is preset, full on, or full off, and whether the current level is higher than, lower than, or equal to this level.", "The switches are wired in line with the main 120-volt AC line.", "Since the switches are at all times either "on"", "or "off"", "and there are no variable resistors used for the dimming function, a parallel set of remote switches, also wired in line with the AC line, may be provided to give full remote capability.", "Thus, another switch box may be provided in a hallway or adjacent room which fully duplicates the functions of the primary switch box without the necessity for duplication of the microcomputer and its associated circuitry.", "The remote switches are wired in parallel with the primary switches through their wall-mounted switch box forming a second parallel input to the microcomputer.", "A primary object of this invention is to provide a light level controller which provides a maximum degree of flexibility in altering levels of light intensity according to the desires of the user.", "A further object of this invention is to provide a light level controller which includes an automatic fader for gradually fading the light intensity level from a current level to a preset level.", "Yet a further object of this invention is to provide a light level controller having means for manually overriding the automatic fader and for making abrupt transitions in light level intensity from a current level to a predetermined level.", "A still further object of this invention is to provide a light level controller having the above features which can be mounted within a standard wall switch panel box and connected to a standard 60-cycle AC household power supply.", "Yet a further of this invention is to provide a light level controller in a wall switch mounting which is microcomputer-controlled and responsive to the state of non-latching switches which provide a digital input signal to the microcomputer.", "A still further object of this invention is to provide a light level controller having a plurality of light control modes in which the particular mode chosen is a function of the period of time that the non-latching control switch is pressed.", "A further object of this invention is to provide a light level controller in a wall switch mounting having a visual indication of the intensity of the light on the room.", "A still further object of this invention is to provide a wall-mounted light level controller having full remote capability.", "The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideraton of the following detailed description of the invention taken in conjunction with the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of a circuit constructed according to the present invention.", "FIG. 2 is a side view of a wall switch mounting containing the circuit of the present invention illustrated in FIG. 1. FIG. 3 is a front view of an alternate type of wall switch mounting.", "FIG. 3(a) is a side view of the wall switch mounting of FIG. 3. FIG. 4 is a flow chart diagram depicting the method of operation of the circuit illustrated in FIG. 1. FIG. 4(a) is a continuation of a portion of the flow chart diagram of FIG. 4. FIG. 4(b) is a further continuation of the flow chart diagram of FIG. 4. FIG. 5 is a waveform diagram illustrating the method of controlling the line voltage input to a light source using the circuit of FIG. 1 DETAILED DESCRIPTION OF THE INVENTION A light source 10 which may be, for example, an incandescent light source drawing between 40 and 2,000 watts of power, is connected to a source of AC power 12 through a thyristor 14.", "The AC source 12 is a standard household power supply, 60-cycle, 120-volt AC.", "The thyristor 14 is a bi-directional SCR controller.", "The control line 11 for the thyristor 14 is connected to a microcomputer 16.", "The microcomputer 16 is powered by a DC power supply 18 and includes an input from a zero crossing detector 20 which is also connected to AC power source 12.", "A wall switch mounting 22 (enclosed within the dotted line in FIG. 1) may include a pair of nonlatching switches 24a and 24b and an LED display 26.", "The LED display may be connected to the microcomputer 16 by a bus 28 which may include any desired plurality of lines.", "In the example shown in FIG. 1, line 28 is an eight line bus.", "Each of the nonlatching switches 24a and 24b includes a rectifier and clamp circuit 30a and 30b, respectively, which provide half-wave rectification and voltage clamping.", "The switches 24a and 24b are connected to AC power source 12 through a resistor 17 and diodes 13 and 15.", "The output of the rectifier and clamp circuits 30a and 30b are connected as inputs to microcomputer 16.", "Microcomputer 16 also includes a clock which may, for example, be a crystal oscillator 32.", "The microcomputer 16 also includes as an input, a reset network 34.", "A remote input 19 may also be provided as a parallel input to circuts 30a and 30b.", "Remote input 19 is in all respects identical to the network of switches 24a and 24b including resistor 17 connected to the AC line and diodes 13 and 15.", "Thus, either the wall mounting 22 or the remote input 19 may initiate the functions discussed herein.", "Between thyristor 14 and light source 10 there is a choke or induction coil 36 which provides current damping for the light source 10.", "Without such a choke 36 the filament in an incandescent light source such as light source 10 may physically oscillate under certain conditions.", "Thyristor 14 has an output comprising AC pulses having relatively fast rise times.", "The choke 36 smooths the shape of these pulses so that there is no ringing or spurious oscillation within the light source 10.", "The input of the microcomputer 16 from the rectifier and clamp circuits 30a and 30b is responsive to a series of sequential square wave pulses.", "These pulses are developed from the line inputs through either switch 24a or 24b.", "For example, if switch 24a is depressed the line voltage is fed to rectifier and clamp circuit 30a which provides half-wave rectification and clamps the voltage peaks to a level compatible with the microcomputer inputs, that is approximately 5 volts.", "The switches 24a and 24b are arranged to provide "up"", "and "down"", "light level changes, respectively.", "A detailed functional description of the consequence of pressing either switch will be explained below, but, in general, switch 24a increases the brightness level of the light source 10 and may therefore be considered an "up"", "switch and switch 24b decreases the brightness level of the light source 10 and may therefore be considered a "down"", "switch.", "Accordingly, rectifier and clamp circuit 30b provides negative-going square wave pulses as an input to microcomputer 16 and the circuit 30a provides positive-going square wave pulses.", "The reset network 34 provides a signal that resets the microcomputer 16 upon initial power up of the system irrespective of fluctuation in the DC power supply 18.", "Such circuits are well known in the electronics art.", "The zero crossing detector 20 determines the zero crossing points of the input power AC waveform from AC power source 12.", "This information is synchronized with the crystal oscillator 32 so that the thyristor 14 may be controlled by gating voltage from the AC power source 12 into the light source 10 at predetermined times relative to the zero crossing points.", "Microcomputer 16 is a single chip microcontroller which may include read only memory and random access memory.", "Such a microcontroller is manufactured by National Semiconductor Co. and bears the model number COP413L.", "The microcomputer 16 receives commands from the rectifier and clamp circuits 30a and 30b, and synchronizes those commands with the zero crossing points of the AC power line by way of a signal from zero crossing detector 20, and provides appropriate firing commands to thyristor 14 over line 11.", "The programs executed by microcomputer 16 and the method of operating switches 24a and 24b to achieve the programmed results will be explained below.", "Referring now to the flow chart diagrams of FIGS. 4, 4(a) and 4(b), there are four possible switch conditions for switches 24a and 24b.", "These are identified as the decision nodes "up held", "down held", "up valid", and "down valid".", "There also exists the possibility that none of the four above conditions exists and the light will remain at its current level by the continuous completing of the zero crossing ("Z.C.") subroutine, shown in the bottom half of FIG. 4, once every 1/120 second.", "This subroutine is responsible for generating a firing or command signal over line 11 which controls the phase angle at which the triac fires during each 1/2 cycle of the 60 cycle AC power input.", "If desired, the Z.C. subroutine may be executed every other half cycle or every third half cycle.", "Thus an instruction could be provided in the program to skip a certain number of half cycles before executing the Z.C. subroutine.", "The effect of such a instruction would be to provide a more gradual automatic fade or preset.", "The first step in the zero crossing subroutine is to determine if the current intensity level "C"", "equals a new or desired intensity level.", "The new level, indicated by the letter "N,"", "may have one of three values.", "It may be equal to the "preset"", "level "full on"", "or "full off.", """, "Thus, in a case where N is equal to C, which would be the case if none of the switch conditions identified in the four decision nodes above currently existed, the microcomputer 16 would determine the time of zero crossing of the AC input wave with reference to its own internal clock.", "As soon as it is determined that a zero crossing has occurred the microcomputer 16 begins counting until it reaches a point in time in the current half-cycle of the AC wave at which the voltage input will cause the light 10 to have the desired level of light intensity N (FIG.", "5).", "This point in time may be expressed as a phase angle of the line input wave.", "At the predetermined phase angle the microcomputer will initiate a firing signal which will cause the thyristor 14 to gate the remaining portion of the AC voltage wave into the light source 10.", "The resultant voltage input which is shown as the "load voltage"", "line in FIG. 5 is a sharply rising pulse whose power content represents a fraction of the total available AC power line output.", "The sharply rising input wave form is smoothed by choke 36 to eliminate ringing or oscillation of the filament in the light source 10.", "The thyristor 14 is fired once each half cycle and after each firing the microcomputer 16 interrogates the inputs from circuits 30a and 30b to determine the status of switches 24a and 24b.", "The interrogation sequence and the resulting computations to determine the proper light level occur during a brief period of time at the beginning and at the end of each half cycle of the input waveform as indicated by the shaded portions under the curve of the input wave in FIG. 5. During these periods no firing signal is generated and the thyristor 14 remains off.", "These are the points in the cycle, however, when the input voltage is lowest and the effect upon power availability is therefore negligible.", "The microcomputer 16 determines the status of the switches 24a and 24b based upon the number of sequential square wave pulses counted at each of the switch inputs from circuits 30a and 30b during each sampling period.", "Depressing either of the switches 24a or 24b will cause circuit 30a or 30b to generate a series of square wave pulses for as long as the switch is depressed.", "Thus, the number of sequential pulses received is a function of the length of time that the user manually depresses the panel (refer to FIGS. 2 and 3) that actuates the switches 24a and 24b.", "The microcomputer 16 counts the number of pulses in order to discriminate between a "hold"", "condition and a "tap"", "condition.", "If the microcomputer 16 reads a predetermined number of pulses "n"", "when it interrogates a switch input it may interpret the condition as a hold, and if it receives a number of pulses greater than a predetermined minimum "m"", "but less than n it may interpret the switch condition as a "tap.", """, "The predetermined minimum is necessary so that the micro-computer will not interpret spurious noise as a valid switch condition.", "Referring again to the top of FIG. 4, if n pulses are counted while the input from rectifying and clamp circuit 30a is being sampled the microcomputer 16 determines that the up switch is being held.", "It then determines whether the current level of light C is at full power or less than full power.", "If the current level of light C is less than full the microcomputer increments C and simultaneously makes the new level just achieved equal to C and the preset level P equal to C. The zero crossing subroutine is then executed.", "The result of this loop is that as long as the user continues to depress switch 24a, the microcomputer 16 will cause C to increment one step at a time per half cycle until the switch is released.", "If switch 24b remains depressed the microcomputer 16 will decrement C simultaneously making N equal to C and P equal to C until the light is either fully off or until the user releases the button controlling switch 24b.", "The operations N=C and P=C are also memory operations and values of N and P are stored in memory for subsequent operations.", "The above described loops represent the preset mode of light control and serve to establish a new value in memory for a level of light intensity P at the same time that a new level of light intensity is being established in the light source 10 through the zero crossing subroutine.", "If during a sampling period the microcomputer 16 discovers a "tap"", "condition on the "up"", "switch 24a, it executes the computational routine shown in FIG. 4(a).", "First the microcomputer 16 determines if the current level of light intensity equals the new or desired level of light intensity N. N could be the preset level stored in memory or could be a level corresponding to full power on.", "If C=N, the microcomputer 16 then determines whether C=full power.", "If yes, the zero crossing subroutine is executed.", "If no, microcomputer 16 determines if N is then equal to P. If yes, the microcomputer makes N equal to full power and executes the zero crossing subroutine.", "If no, the microcomputer 16 makes N equal to P and executes the zero crossing subroutine.", "When N=P or N=full and the zero crossing subroutine is executed, N will not be equal to C and therefore the command "move C one towards N"", "in the zero crossing subroutine will be executed.", "Since the computational routine in FIG. 4(a) established N as a value which was not equal to the current value C of the light intensity level, the zero crossing subroutine will repeat itself until N=C (assuming no switches have been depressed in the meantime), at which time the level of light intensity will remain constant at the new level N. Thus, when N does not equal C in the zero crossing subroutine, an automatic fade mode is initiated which moves C one incremental value towards N each time the loop is repeated.", "This loop is executed a chosen number of times a second and by choosing that number or the magnitude of the incremental steps through which N moves, the designer may regulate the slope of the automatic fade mode.", "For example, if the increments of N are made very small it would take the completion of more loops to move C to the value of N (a slower fade) than it would if the incremental values of C were made larger (a faster fade).", "According to the preferred embodiment, each half cycle is divided into 160 incremental steps and the Z.C. subroutine is executed every third half cycle.", "This results in a fade in which the incremental increases or decreases in light intensity are imperceptible and the fade appears to be smooth and continuous.", "If the up button is tapped while the automatic fade mode is in operation, a different set of conditions will exist at the first decision node in FIG. 4(a).", "In this case C will not be equal to N because N=P≠C and the microcomputer 16 will be in the process of fading C towards N. In such a case the microcomputer first determines if N is greater than or less than C. If N is greater than C, C is assigned a value that is equal to N. This causes the level of light intensity to abruptly jump from C to N. When the zero crossing subroutine is executed N will then be equal to C and the automatic fade mode will be circumvented as shown in FIG. 4. Thus, the difference between a fade and an abrupt transition lies in making C either equal to a new or desired level N or in making C equal to some value that is not N prior to execution of the zero crossing subroutine.", "For example, if N is not greater than C in FIG. 4(a), microcomputer 16 makes N equal to P, a preset level which is lower than C. Since N is then not equal to C at the commencement of the zero crossing subroutine, C moves one step at a time towards N which is lower than C, and a downward automatic fade is commenced.", "The operation of the switch when the down button is tapped is similar in operation to the situation encountered when the up button is tapped.", "If no fade is in progress when the down button is tapped, C will be equal to N. Subsequently, N will be made equal to zero and the zero crossing subroutine will cause the light intensity level to fade to off.", "If a fade is in progress such that when the down button is tapped, N is either equal to, greater than, or less than C, the light either fades to off or makes an abrupt transition to off.", "A delay mode may be provided when a down fade is in progress to make downward fading more gradual than upward fading.", "Thus, if during a Z.C. subroutine a downward fade is detected, the microcomputer 16 delays the thyristor firing until the delay subroutine has been completed, incrementing the delay function one step at a time until its completion.", "If the down button is pressed while an up fade is in progress, N is made equal to zero and C fades toward N in the zero crossing subroutine.", "If the down is pushed while the system is fading towards off, N will be less than C and microcomputer 16 will make C equal to N which will cause the auto-fade mode in the zero crossing subroutine to be circumvented and the light will make an abrupt transition to off.", "Physically the system represented in the block diagram of FIG. 1 may be enclosed in a wall mounted light switch.", "One example of such a switch is shown in the side view of the switch in FIG. 2. The switch of FIG. 2 includes a cover plate 38 and a rectangular bezel 40.", "The bezel 40 encloses a rocker mounted panel 42 which includes two inwardly extending fingers 44a and 44b.", "The fingers 44a and 44b are adapted to make contact with non-latching push buttons 46a and 46b.", "The push buttons 46a and 46b are mounted on a PC board 48 which also includes the circuit elements shown in the block diagram of FIG. 1 with the exception of the incandescent light source 10 and the AC power supply 12.", "The PC board 48 is mounted to an aluminum heat sink 50.", "An air gap safety switch 52 is also mounted to the heat sink which breaks the circuit when slider 67 is actuated.", "The switch components are enclosed in a box 54 of a size compatible with the current size standards for wall-mounted light switch boxes.", "Inside the box 54 is choke coil 36.", "An aperture 56 in box 54 provides a means for connection to the incandescent light source 10 by way of wire 58.", "The rocker panel 42 includes apertures 60 (only one such aperture is shown in FIG. 2) in which are mounted light-emitting diodes (LEDs) such as LED 62.", "LED 62 is part of LED display 26 identified in FIG. 1. There may be as many LEDs as desired.", "According to the preferred embodiment there should be eight because the National Semiconductor chip used for microcomputer 16 has eight outputs which may be arranged to provide a signal indicating the current level of light intensity.", "For example, the LEDs may be arranged in an array extending along the rocker panel 42 from top to bottom so that the vertical position in the array of the LED that is on indicates the level of brightness.", "The nonlatching push buttons 46a and 46b correspond functionally to switches 24a and 24b in FIG. 1. Thus, depressing the upper portion of the rocker panel 42 will cause finger 44a to engage push button 46a and close the "up"", "switch 24a.", "Similarly, pressing the lower half of rocker panel 42 will close "down"", "switch 24b.", "The rocker panel 42 is biased by a pair of angled legs 64a and 64b that fit snugly within an aperture in heat sink 50.", "The legs 64a and 64b cause the fingers 44a and 44b to release the push buttons 46a and 46b when there is no manual pressure on either half on the rocker panel 42.", "An alternative embodiment of the wall mounting for FIG. 2 is shown in FIGS. 3 and 3a.", "The wall mounting of FIG. 3 includes a cover plate 66 and a two push plates 68a and 68b.", "LEDs 62 are arranged vertically from top to bottom through apertures in plates 68a and 68b, respectively.", "Each of the push plates 68a and 68b include inwardly protruding fingers 70a and 70b which engage pushbuttons 72a and 72b which are similar in all respects to pushbuttons 46a and 46b.", "The plates 68a and 68b are biased by a biasing means such as a spring (not shown).", "The electrical components of FIG. 1 are housed within a box 74 in a way similar to that depicted in FIG. 2. Although non-latching switches are preferred, a center-off toggle switch (i.e., standard wall-mounted switch) could be used.", "The user must simply momentarily depress the switch in either direction and return it to center for a "tap"", "and hold it longer for a "hold.", """, "In actual operation, pushing the up panel 68a or the upper half of rocker switch 42 when the light is off will cause the level of light intensity to rise and fade gradually towards the preset level.", "If the fade is in progress, tapping panel 68a or rocking switch 42 in the up position will cause the light to make an abrupt transition to the preset level.", "If up is pressed while the light is at the preset level the light will fade to a full power condition and if up is pressed while the light is fading to a full up condition the light will make an abrupt transition to full power.", "If down switch 68b or the lower half of rocker panel 42 is depressed, indicating a down switch condition, the light will fade towards off or zero.", "If down is pushed while a down fade is in progress, the light will make an abrupt transition to off.", "If, on the other hand, the up switch panel 68a or the upper portion of rocker panel 42 is pushed while a down fade is in progress, the light will fade to the preset level.", "Whenever panel 68a or 68b is held in one position for a period of more than transitory duration, the light level will move up or down stopping only when the panel is released.", "Simultaneously, the microcomputer 16 will store that current level of light intensity in memory as the preset level P. This preset remains in memory until a subsequent holding of either of the switches to establish a new level.", "If desired, the switching function may be divided between "tap"", "and "hold"", "and a second set of switches may be provided to take over one of the above functions.", "For example, a rocker panel could be dedicated to upward and downward taps and a second panel or toggle could provide the hold function for preset.", "Moreover, it is not necessary that the tap or hold functions depend on the time duration of the depression of the switches.", "If two sets of switches are used, the microcomputer 16 may be programmed to accept one set of switches at one input pin as the tap input and the second set as the hold, or preset, input on another pin regardless of length of time that either is held down.", "The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow." ]
RELATED APPLICATIONS [0001] The present application is based on, and claims priority from, French Application Number 0800674, filed Feb. 8, 2008, the disclosure of which is hereby incorporated by reference herein in its entiretly. TECHNICAL FIELD [0002] The present invention relates to the field of methods and systems for optimizing the locating of an aircraft in airports and, more particularly, in the take-off and landing phases, and notably in the air-ground and ground-air transition phases. BACKGROUND OF THE INVENTION [0003] Nowadays, in most aircraft, the calculation of the aeroplane position is performed on the basis of a ground locating system for the airport rolling phases and an in-flight locating system for take-off, landing and cruising flight. [0004] With respect to the ground locating system, generally the latter is handled by a computer, of FMS type, the acronym signifying “Flight Management System”. In particular, the computer fulfils the flight plan display, computation and aeroplane position display functions. [0005] With respect to the ground locating system, generally the latter is handled by another computer, in certain cases called ANS, the acronym standing for “Airport Navigation System”. The latter fulfils the aeroplane map display, computation and ground position display functions. [0006] These two locating systems are nowadays independent inasmuch as they are interfaced with other equipment or systems incorporating sensors that are different depending on whether the aircraft is in the rolling, take-off, stabilized flight or landing phase. Notably, the dynamic aeroplane parameters and the contextual navigation parameters (obstacles, weather, runways, traffic) can differ according to one or other of the navigation systems. [0007] When rolling, the longitudinal speeds are low and can be zero, when stopped, or even negative, in a so-called “pushback” reversing manoeuvre, the lateral speeds are almost zero, except when turning. [0008] Currently, the accuracy of the ground locating systems is of the order of a metre for the rolling phases. [0009] The ground locating system during the rolling phase generally uses sensors of GPS or IRS type, IRS standing for “Inertial Reference System”. This locating system is often coupled, in the airports, with a precision local augmentation system of GBAS type, the acronym standing for “Ground-based augmentation system”. The latter system makes it possible to more accurately locate the aircraft thanks to an error correction done on the ground. [0010] Moreover, this information can be tallied with information originating from antennas fixed to the ground at known positions capable of fixing the aircraft by multilateration. In certain cases, cameras make it possible to view the markings on the ground or even to know the number of turns of the wheels of the landing gears for example. [0011] The ground locating system can also take into account data obtained from the dynamics of the aircraft originating from sensors placed on the braking system or even on the landing gears for example. [0012] In flight, the longitudinal speeds are high, generally above 100 knots, the lateral speed depends on the wind, and can reach 250 knots, and finally the vertical speed is non-zero. [0013] Currently, the accuracies of the in-flight locating systems are of the order of 200 m in approach and greater than a kilometre when cruising. [0014] The in-flight locating system uses, to fix the positioning of the aircraft, mainly equipment comprising sensors of IRS or GPS type and a regional augmentation system of SBAS type, the acronym standing for “Satellite-based augmentation system”. The latter system makes it possible to locate with greater accuracy the aircraft thanks to an error correction made by satellites. [0015] In some cases, it is possible for such equipment to be coupled with a local augmentation system of GBAS type such as an approach configuration for landing. [0016] The in-flight locating system can also use equipment picking up the signals from the radio navigation beacons of VOR or DME type, the acronym DME standing for “Distance Measurement Equipment”. [0017] Nowadays, the in-flight locating systems are more accurate than the ground locating systems when the aircraft is in flight and conversely the ground locating systems are more accurate than the in-flight locating systems when the aircraft is on the ground. [0018] The two systems can be used in any configuration of the aircraft, on the ground or in flight. Generally, the system used is that of the most appropriate context of the aircraft. In other words, in the rolling phase, the crew selects the ground locating system and in the flight phase, of cruising flight type, the crew selects the in-flight locating system. [0019] However, there is a problem in the transitional take-off and landing phase during the changeover from one locating system to the other in which the accuracies of the locating systems do not allow for a continuous changeover of the position of the aircraft. This problem causes trouble for the crew, notably for the display of the aeroplane position when there is a changeover between the display of the airport map and the display of the flight plan. [0020] Moreover, in the take-off phase, there is a problem associated with the offset between the theoretical position, called the designated take-off point, and the actual position of the aircraft on the runway just before throttle-up. [0021] This problem is caused either by the uncertainty concerning the position of the aircraft on the runway relative to the theoretical point, or from an access to the runway via an access ramp not originally planned, a change having been made during the rolling phase. Currently, the crew is responsible for modifying the offset manually in the onboard computer in order to resolve the difference between the theoretical position and the actual position of the aircraft on the runway. [0022] One aim of the invention is to overcome the abovementioned drawbacks. SUMMARY OF THE INVENTION [0023] The invention proposes a method of optimizing the calculation of the position of the aircraft in all the take-off phases, that is, from its stopping point, just before throttle-up, to a point in the flight plan at which the flight is considered stabilized. Moreover, the invention makes it possible to optimize the calculation of its position in the landing phase. [0024] The invention makes it possible to implement a method, in the air-ground and ground-air transition phases, of hybrid calculation between its position measured on the basis of an in-flight locating system and its position measured on the basis of a ground locating system. [0025] Advantageously, the method of optimizing the locating of an aircraft during the take-off or landing phase comprising a transition step, the latter being defined between two events (A 0 , AS), the first event being a condition of contact between the aircraft and the runway and the second event being a threshold condition defining a stabilized flight phase, wherein the transition step comprises the determination of at least one “transition position” of the aircraft by a weighting between the “ground position” determined by the ground locating system and the “flight position” determined by the in-flight locating system. [0026] Advantageously, a first step, at the moment of throttle-up, comprises the determination of at least one position of the aircraft by the onboard computer, denoted “starting position”; a second step ( 20 ) preceding the transition step, when the aircraft accelerates, comprises the calculation of at least one “ground position” of the aircraft by the ground locating system; a final step ( 22 ) following the transition step, beyond the threshold condition (AS), comprises the determination of at least one “flight position” of the aircraft by the in-flight locating system. [0027] Advantageously, a preliminary step, preceding the transition step, comprises the calculation of a threshold position of the aircraft, beyond which the position of the aircraft is calculated in a hybrid manner; a landing step, following the transition step, when the aircraft is in contact with the runway, comprises the calculation of at least one “ground position” of the aircraft by the ground locating system. [0028] Advantageously, the first step comprises the automatic realigning of the “starting position” in the onboard computer based on a calculation of the difference measured between the designated take-off point, denoted “theoretical take-off position”, and the actual position of the aircraft obtained, just before throttle-up, by the ground locating system. [0029] Advantageously, the “take-off position” is determined by the designation, in the onboard computer, of an element of the airport database, the designation being produced in preparation of the flight by the crew. [0030] Advantageously, the first event used to calculate the position of the aircraft in the transition step is triggered for a change of altitude of the aircraft. [0031] Advantageously, the first event is triggered for a change of pressure on the aircraft landing gears. [0032] Advantageously, in a first embodiment, the threshold condition is validated by a crossed altitude threshold. [0033] Advantageously, in a second embodiment, the threshold condition is validated by a crossed rolling threshold. [0034] Advantageously, in a third embodiment, the threshold condition is validated by a predetermined duration. [0035] Advantageously, a “transition position” in the transition phase is calculated on the basis of a percentage of the first position (PCT_ROU) and a percentage of the second position (PCT_VOL). [0036] Advantageously, the latitude of the aircraft, in the transition phase, is determined by the relation: [0000] Lat(aircraft)=[PCT_VOL·Lat_VOL]+[(100−PCT_VOL)·Lat_ROU], [0000] in which the latitude calculated on the basis of the ground locating system is denoted Lat_ROU and the latitude calculated on the basis of the in-flight locating system is denoted Lat_VOL and in which PCT_VOL represents the percentage of the weighting of the position obtained from the in-flight locating system. [0037] Advantageously, the longitude of the aircraft, in the transition phase, is determined by the relation: [0000] Long(aircraft)=[PCT_VOL×Long_VOL]+[(100−PCT_VOL)×Long_ROU], [0000] in which the longitude calculated on the basis of the ground locating system is denoted Long_ROU and the latitude calculated on the basis of the in-flight locating system is denoted Long_VOL, and in which PCT_VOL represents the percentage of the weighting of the position obtained from the in-flight locating system. [0038] Advantageously, the percentage of the first position (PCT_ROU) and the percentage of the second position (PCT_VOL) are determined on the basis of an altitude-dependent linear relation. [0039] Advantageously, the latitude and the longitude of the current position of the aircraft are determined by the following relations: [0000] LAT  ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL ,  LONG ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0000] in which ALT(AS) is the altitude at the point from which the position of the aircraft is entirely calculated on the basis of the in-flight locating system and LAT(aeroplane) is the current altitude of the aircraft. [0040] Advantageously, the percentage of the first position (PCT_ROU) and the percentage of the second position (PCT_VOL) are determined on the basis of a time-dependent linear relation. [0041] Advantageously, the latitude and the longitude of the current position of the aircraft are determined by the following relations: [0000] LAT  ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LAT_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LAT_VOL ,  LONG ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LONG_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LONG_VOL , [0000] in which Ts is the time of passage at the point from which the position of the aircraft is entirely calculated on the basis of the in-flight locating system, T 0 is the time of passage when the aircraft leaves the runway and T(aeroplane) is the local time of the aircraft. [0042] Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention. Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive. BRIEF DESCRIPTION OF THE DRAWINGS [0043] The present invention is illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein: [0044] FIG. 1A : a diagram of the data making it possible to implement the first step of the first method according to the invention; [0045] FIG. 1B : a diagram illustrating the principle of realigning of the positioning of an aircraft on a take-off runway according to the first inventive method; [0046] FIG. 2 : an example of hybridization of the locating of the aircraft in the transitional take-off phase; [0047] FIG. 3 : the diagram of the data used to hybridize the locating of the aircraft. DETAILED DESCRIPTION OF THE INVENTION [0048] The invention makes it possible to optimize the calculation of the position of the aircraft notably by a first method corresponding to the take-off phase and a second method corresponding to the landing phase, the inventive concepts of the two methods being the same. [0049] During the take-off phase, a first method according to the invention comprises several steps. [0050] A first step of the first method consists in automatically readjusting, before throttle-up, the theoretical take-off position in the onboard computer. The theoretical take-off position is generally designated on preparation of the flight by the crew. [0051] In the preparation of the flight generally performed in the parking area, the pilot initializes, through the onboard computer, the inertial units and the current position of the aircraft. The crew has to select an access ramp to the runway or at least one element of the airport database in order to define the runway entry point. [0052] The take-off comprises a rolling phase and a flight phase. The rolling of the aircraft prior to take-off proceeds from the initialization of the flight until the moment when the aircraft leaves the runway. [0053] The rolling itself comprises a first rolling phase of the initialization of the flight until the moment of throttle-up and an acceleration phase on the runway between throttle-up and the moment when the aircraft leaves the runway. [0054] The method according to the invention makes it possible to establish in this first step an automatic realigning in the computer of the take-off position actually measured based on the ground locating system. [0055] FIG. 1A represents a schematic view of a runway 1 and of two access ramps B 1 , B 2 . In the example of FIG. 1A , the crew has previously selected ramp B 1 so as to be positioned on the theoretical take-off position 3 . [0056] From the airport database and the selected element B 1 , the computer determines the point of intersection 2 of the ramp B 1 and the runway 1 and the theoretical take-off point 3 . [0057] The theoretical take-off point of the runway generated by the computer is situated at a distance from the point of intersection 2 calculated so that the aircraft can perform its final turning before the take-off and be positioned facing the runway. This final point of the runway generated in this way from the selection of the element by the crew is called the “theoretical take-off point”. [0058] In reality, the aircraft is rarely exactly placed at the theoretical take-off point generated by the computer, and can be more or less offset from this position. In the example of FIG. 1A , the aircraft is situated at a position 4 when stopped and is ready for throttling-up. [0059] The invention makes it possible, based on the ground locating system, to measure the actual position 4 of the aircraft and automatically update this actual take-off position in the computer so that this final value replaces the theoretical position 3 . [0060] The calculation of this offset is performed from the computer and the database of the airport elements which comprises the coordinates and the geometrical shapes, notably of the runways, of the runway thresholds, of the runway axes, of the access ramps, of the access ramp axes, of the intersections between the taxiways and the runways and the intersections between runways themselves, and of the specific markings on the runways. [0061] The theoretical take-off point generated in this way following the selection of an element by the crew is the point of the take-off runway that presents the highest probability of the aircraft being positioned there. The aircraft has previously used the element of the airport selected by the crew. [0062] For this, a mapping rule associates an element of the database of airport elements with a determined point of the runway that is optimal for the take-off, i.e. the theoretical take-off point. [0063] In the phase of positioning of the aircraft on the take-off runway, the onboard computer detects at regular intervals if the aircraft is in the take-off situation, generally the aircraft is stopped in this situation and the crew is preparing to throttle up. This final situation is recorded by a condition, denoted take-off condition. [0064] When the take-off condition is validated, the deviation between the theoretical take-off position and the actually measured position of the aircraft by the ground locating system is measured. When the value of the measured deviation is situated above a tolerance threshold, the computer realigns the position of the aircraft on the actually measured position. Below the threshold, the value of the theoretical take-off position is maintained in the computer. [0065] FIG. 1B represents a Computer K, such as an ANS, having calculated a take-off point “PT_take-off” from the selection, by the crew, of an element of the airport database, called “database airport” in FIG. 1B . [0066] The method according to the invention therefore makes it possible to compare the position of the take-off point PT_take-off with the current position of the aircraft, the latter being measured on the basis of the ground locating system. [0067] The current position, measured by the ground locating system SYS_LOC_SOL, is accompanied by an uncertainty margin linked to the context of the aircraft and to the locating system. [0068] If the “take-off” condition is validated, that is, the aircraft is stopped and the throttling-up can be performed, then, according to the value of the difference of the measured positions between the take-off point and the current position of the aircraft, an automatic realignment of the take-off point is performed in the FMS, an offset generally called “take-off shift”. This realignment makes it possible to update the computer so that the initial take-off point is a correct point supplied to the in-flight locating system. [0069] The automatic realignment of the take-off position is carried out for a value of the difference of the measured positions that exceeds a predetermined threshold. This final threshold value takes into account the uncertainty margins measured by the aircraft position detection equipment. [0070] The second step of the method is performed in the acceleration phase of the aircraft on the take-off runway between the moment of throttling-up and the moment when the aircraft leaves the runway and is no longer in contact with the runway. [0071] In this step, the position of the aircraft is entirely measured from the ground locating system, the latter being handled by a system of sensors of GPS and/or IRS type with a local augmentation system of GBAS type and possibly using a multilateration based on antennas fixed to the ground, the positions of which are known. [0072] FIG. 2 represents the distribution of the weighting of the measurements of the positions (LOC_SOL, LOC_VOL) of the aircraft by the ground locating system and by the in-flight locating system during the take-off phase. [0073] The weighting of the measurements in the method according to the invention is different depending on whether the aircraft is in one of the three distinct phases represented: acceleration, take-off or the transition phase and a final flight phase, denoted stabilization phase. [0074] The position of the aircraft, throughout the acceleration phase, is contained in the part 20 of the curve between the take-off point, represented by the origin of the graph, and the point where the aircraft leaves the runway, represented by the point A 0 . [0075] A third step of the method, following the acceleration of the aircraft, comprises the calculation of at least one position between the point A 0 where the aircraft leaves the runway and a threshold point As from which the position of the aircraft is entirely measured based on the in-flight locating system. [0076] FIG. 2 represents, in the part 21 of the curve between the point A 0 and the point AS, a linear hybridization between the measurement of the position of the aircraft by the ground locating system and the measurement of the position by the in-flight locating system. [0077] The method according to the invention makes it possible to have several indicators to determine the point A 0 . This final point can be determined after the rotation of the aircraft, involving a crossed altitude condition above the take-off runway or even by an indicator of the overshooting of a pressure threshold on the landing gears. As an example, the altitude condition of the point A 0 can be obtained for an altitude threshold above the runway of 10 feet. [0078] The point AS is considered as a threshold position that no longer requires the accuracy of the ground locating system. This final position can be determined in several ways depending on the embodiments. The altitude condition of the point AS can be obtained for a predetermined altitude threshold above the ground; it could for example be 50 feet. [0079] In another embodiment, the point AS can be determined by a condition of a crossed rolling threshold, that is, after the aircraft has performed a turn. [0080] A variant embodiment of the invention makes it possible to determine the point AS from a delay corresponding to a predetermined time after throttling-up. [0081] During this transition phase following take-off, when the aircraft has left the runway, the invention proposes to measure, in this step, the position of the aircraft by a weighting expressed as a percentage of a first position, denoted PCT ROU, determined on the basis of the ground locating system and a second position, denoted PCT VOL, determined on the basis of the in-flight locating system. [0082] This weighting can be a function of the altitude, of the speed or of the roll of the aircraft or even a combination of these data. The weighting can also be carried out for predetermined period of time, for example from the moment of throttling-up. [0083] The curve linking the two positions deriving from their respective locating system may be linear or indeed non-linear. In the latter case, it may be a curve of the second degree or logarithmic for example, or even any other basic function. [0084] An exemplary implementation of hybridization based on a weighting of the location of the aircraft according to the positions of each locating system makes it possible to equally determine the latitude, denoted Lat(aeroplane), and the longitude, denoted Long(aeroplane), of the aircraft by the following relations: [0000] LAT(aeroplane)=[PCT_VOL*LAT_VOL]+[(100%−PCT_VOL)*LAT_ROU]; [0000] in which the latitude calculated on the basis of the ground locating system is denoted LAT_ROU and the latitude calculated on the basis of the in-flight locating system is denoted LAT_VOL; and [0000] LONG(aeroplane)=[PCT_VOL*LONG_VOL]+[(100%−PCT_VOL)*LONG_ROU]; [0000] in which the longitude calculated on the basis of the ground locating system is denoted LONG_ROU and the longitude calculated on the basis of the in-flight locating system is denoted LONG_VOL. [0085] FIG. 2 represents a linear slope between A 0 and AS where the hybridization of the positions LOC_SOL and LOC_VOL is performed according to the altitude. The percentages PCT_VOL and PCT_ROU corresponding to the hybridization of the positions deriving from the in-flight and ground locating systems are therefore functions of the altitude. [0086] In the example, the relation, linking the positions LOC_SOL and LOC_VOL with the altitude, is linear between the points A 0 and AS. ALT(aeroplane) represents the instantaneous altitude of the aircraft and ALT(AS) represents the altitude at the point AS. [0087] The relations then become: [0000] LAT  ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL LONG ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0000] in which the latitude calculated on the basis of the ground locating system is denoted LAT_ROU and the latitude calculated on the basis of the in-flight locating system is denoted LAT_VOL; and In which the longitude calculated on the basis of the ground locating system is denoted LONG_ROU and the longitude calculated on the basis of the in-flight locating system is denoted LONG_VOL. [0088] In this final example, after the passage at the point AS, the altitude, called “threshold altitude”, the calculation of the position of the aircraft is performed solely by the in-flight locating system. [0089] The following then apply: PCT_ROU=0% and PCT_VOL=100%. [0090] In another embodiment, the percentages PCT_VOL and PCT_ROU corresponding to the hybridization of the positions deriving from the in-flight and ground locating systems are functions of time. T(aeroplane) is used to denote the local time of the aircraft expressed in seconds, Ts the planned time at which the aircraft uses only its in-flight locating system corresponding to the point AS, and T 0 the time, expressed in seconds, at which the aircraft leaves the runway, this point corresponding to the point A 0 in FIG. 2 . [0091] The relations then become: [0000] LAT  ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LAT_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LAT_VOL LONG ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LONG_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LONG_VOL [0092] When the time Ts has elapsed, the position of the aircraft uses 100% of the position deriving from the in-flight locating system. [0093] A second method makes it possible to calculate, on the basis of a hybridization similar to that used on take-off, the position of the aircraft when the latter is in the approach phase. An altitude, time or flying mode threshold condition, for example on final levelling-off, makes it possible to determine a hybrid calculation mode. [0094] Until the condition is reached, that is, the aircraft is in cruising flight mode and upstream of the final approach phase, the position of the aircraft is entirely determined on the basis of the in-flight locating system. [0095] In the final transitional approach phase, a hybridization of the calculation of the position of the aircraft between the position deriving from the in-flight locating system and from the ground locating system can be determined as a function of the altitude. [0000] The relations are as follows: [0000] LAT  ( Aeroplane ) = ALT  ( aeroplane ) - ALT  ( AS ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL LONG ( Aeroplane ) = ALT  ( aeroplane ) - ALT  ( AS ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0096] In the same way as in the take-off phase, a variant embodiment makes it possible to implement a method in which the hybridization of the position of the aircraft is a function of time. [0097] Finally, when the aircraft makes contact with the runway, this condition being determined by a measurement of the altitude or of a pressure of the landing gears for example, the position of the aircraft is then entirely determined on the basis of the ground locating system, as well as during the rolling phases preceding the landing. [0098] FIG. 3 represents the principle of hybridization of the position of the aircraft based on the data obtained from the aircraft computer. LOC VOL represents the position deriving from the in-flight locating system, LOC SOL represents the position deriving from the ground locating system. The hybridization between the two measured positions is checked and performed on the basis of the data associated with the context of the aircraft: the time determined by the computer clock, the pressure of the landing gear by sensors positioned on the aircraft, the altitude, the roll and the speed determined on the basis of the aircraft's onboard computer. The computer is then capable of determining a hybridized position in the take-off and approach phases. [0099] It will be readily seen by one of ordinary skill in the art that the present invention fulfils all of the objects set forth above. After reading the foregoing specification, one of ordinary skill in the art will be able to affect various changes, substitutions of equivalents and various aspects of the invention as broadly disclosed herein. It is therefore intended that the protection granted hereon be limited only by definition contained in the appended claims and equivalents thereof.
The present invention relates to the field of methods and systems for optimizing the locating of an aircraft in airports and, more particularly, in the take-off and landing phases, and notably in the air-ground and ground-air transition phases. The method of optimizing the locating of an aircraft during the take-off or landing phase comprising a transition step ( 21 ), the latter being defined between two events (A 0, AS), the first event being a condition of contact between the aircraft and the runway and the second event being a threshold condition defining a stabilized flight phase, is wherein the transition step ( 21 ) comprises the determination of at least one “transition position” of the aircraft by a weighting between the “ground position” (LOC_SOL) determined by the ground locating system and the “flight position” (LOV_VOL) determined by the in-flight locating system.
Condense the core contents of the given document.
[ "RELATED APPLICATIONS [0001] The present application is based on, and claims priority from, French Application Number 0800674, filed Feb. 8, 2008, the disclosure of which is hereby incorporated by reference herein in its entiretly.", "TECHNICAL FIELD [0002] The present invention relates to the field of methods and systems for optimizing the locating of an aircraft in airports and, more particularly, in the take-off and landing phases, and notably in the air-ground and ground-air transition phases.", "BACKGROUND OF THE INVENTION [0003] Nowadays, in most aircraft, the calculation of the aeroplane position is performed on the basis of a ground locating system for the airport rolling phases and an in-flight locating system for take-off, landing and cruising flight.", "[0004] With respect to the ground locating system, generally the latter is handled by a computer, of FMS type, the acronym signifying “Flight Management System.”", "In particular, the computer fulfils the flight plan display, computation and aeroplane position display functions.", "[0005] With respect to the ground locating system, generally the latter is handled by another computer, in certain cases called ANS, the acronym standing for “Airport Navigation System.”", "The latter fulfils the aeroplane map display, computation and ground position display functions.", "[0006] These two locating systems are nowadays independent inasmuch as they are interfaced with other equipment or systems incorporating sensors that are different depending on whether the aircraft is in the rolling, take-off, stabilized flight or landing phase.", "Notably, the dynamic aeroplane parameters and the contextual navigation parameters (obstacles, weather, runways, traffic) can differ according to one or other of the navigation systems.", "[0007] When rolling, the longitudinal speeds are low and can be zero, when stopped, or even negative, in a so-called “pushback”", "reversing manoeuvre, the lateral speeds are almost zero, except when turning.", "[0008] Currently, the accuracy of the ground locating systems is of the order of a metre for the rolling phases.", "[0009] The ground locating system during the rolling phase generally uses sensors of GPS or IRS type, IRS standing for “Inertial Reference System.”", "This locating system is often coupled, in the airports, with a precision local augmentation system of GBAS type, the acronym standing for “Ground-based augmentation system.”", "The latter system makes it possible to more accurately locate the aircraft thanks to an error correction done on the ground.", "[0010] Moreover, this information can be tallied with information originating from antennas fixed to the ground at known positions capable of fixing the aircraft by multilateration.", "In certain cases, cameras make it possible to view the markings on the ground or even to know the number of turns of the wheels of the landing gears for example.", "[0011] The ground locating system can also take into account data obtained from the dynamics of the aircraft originating from sensors placed on the braking system or even on the landing gears for example.", "[0012] In flight, the longitudinal speeds are high, generally above 100 knots, the lateral speed depends on the wind, and can reach 250 knots, and finally the vertical speed is non-zero.", "[0013] Currently, the accuracies of the in-flight locating systems are of the order of 200 m in approach and greater than a kilometre when cruising.", "[0014] The in-flight locating system uses, to fix the positioning of the aircraft, mainly equipment comprising sensors of IRS or GPS type and a regional augmentation system of SBAS type, the acronym standing for “Satellite-based augmentation system.”", "The latter system makes it possible to locate with greater accuracy the aircraft thanks to an error correction made by satellites.", "[0015] In some cases, it is possible for such equipment to be coupled with a local augmentation system of GBAS type such as an approach configuration for landing.", "[0016] The in-flight locating system can also use equipment picking up the signals from the radio navigation beacons of VOR or DME type, the acronym DME standing for “Distance Measurement Equipment.”", "[0017] Nowadays, the in-flight locating systems are more accurate than the ground locating systems when the aircraft is in flight and conversely the ground locating systems are more accurate than the in-flight locating systems when the aircraft is on the ground.", "[0018] The two systems can be used in any configuration of the aircraft, on the ground or in flight.", "Generally, the system used is that of the most appropriate context of the aircraft.", "In other words, in the rolling phase, the crew selects the ground locating system and in the flight phase, of cruising flight type, the crew selects the in-flight locating system.", "[0019] However, there is a problem in the transitional take-off and landing phase during the changeover from one locating system to the other in which the accuracies of the locating systems do not allow for a continuous changeover of the position of the aircraft.", "This problem causes trouble for the crew, notably for the display of the aeroplane position when there is a changeover between the display of the airport map and the display of the flight plan.", "[0020] Moreover, in the take-off phase, there is a problem associated with the offset between the theoretical position, called the designated take-off point, and the actual position of the aircraft on the runway just before throttle-up.", "[0021] This problem is caused either by the uncertainty concerning the position of the aircraft on the runway relative to the theoretical point, or from an access to the runway via an access ramp not originally planned, a change having been made during the rolling phase.", "Currently, the crew is responsible for modifying the offset manually in the onboard computer in order to resolve the difference between the theoretical position and the actual position of the aircraft on the runway.", "[0022] One aim of the invention is to overcome the abovementioned drawbacks.", "SUMMARY OF THE INVENTION [0023] The invention proposes a method of optimizing the calculation of the position of the aircraft in all the take-off phases, that is, from its stopping point, just before throttle-up, to a point in the flight plan at which the flight is considered stabilized.", "Moreover, the invention makes it possible to optimize the calculation of its position in the landing phase.", "[0024] The invention makes it possible to implement a method, in the air-ground and ground-air transition phases, of hybrid calculation between its position measured on the basis of an in-flight locating system and its position measured on the basis of a ground locating system.", "[0025] Advantageously, the method of optimizing the locating of an aircraft during the take-off or landing phase comprising a transition step, the latter being defined between two events (A 0 , AS), the first event being a condition of contact between the aircraft and the runway and the second event being a threshold condition defining a stabilized flight phase, wherein the transition step comprises the determination of at least one “transition position”", "of the aircraft by a weighting between the “ground position”", "determined by the ground locating system and the “flight position”", "determined by the in-flight locating system.", "[0026] Advantageously, a first step, at the moment of throttle-up, comprises the determination of at least one position of the aircraft by the onboard computer, denoted “starting position”;", "a second step ( 20 ) preceding the transition step, when the aircraft accelerates, comprises the calculation of at least one “ground position”", "of the aircraft by the ground locating system;", "a final step ( 22 ) following the transition step, beyond the threshold condition (AS), comprises the determination of at least one “flight position”", "of the aircraft by the in-flight locating system.", "[0027] Advantageously, a preliminary step, preceding the transition step, comprises the calculation of a threshold position of the aircraft, beyond which the position of the aircraft is calculated in a hybrid manner;", "a landing step, following the transition step, when the aircraft is in contact with the runway, comprises the calculation of at least one “ground position”", "of the aircraft by the ground locating system.", "[0028] Advantageously, the first step comprises the automatic realigning of the “starting position”", "in the onboard computer based on a calculation of the difference measured between the designated take-off point, denoted “theoretical take-off position”, and the actual position of the aircraft obtained, just before throttle-up, by the ground locating system.", "[0029] Advantageously, the “take-off position”", "is determined by the designation, in the onboard computer, of an element of the airport database, the designation being produced in preparation of the flight by the crew.", "[0030] Advantageously, the first event used to calculate the position of the aircraft in the transition step is triggered for a change of altitude of the aircraft.", "[0031] Advantageously, the first event is triggered for a change of pressure on the aircraft landing gears.", "[0032] Advantageously, in a first embodiment, the threshold condition is validated by a crossed altitude threshold.", "[0033] Advantageously, in a second embodiment, the threshold condition is validated by a crossed rolling threshold.", "[0034] Advantageously, in a third embodiment, the threshold condition is validated by a predetermined duration.", "[0035] Advantageously, a “transition position”", "in the transition phase is calculated on the basis of a percentage of the first position (PCT_ROU) and a percentage of the second position (PCT_VOL).", "[0036] Advantageously, the latitude of the aircraft, in the transition phase, is determined by the relation: [0000] Lat(aircraft)=[PCT_VOL·Lat_VOL]+[(100−PCT_VOL)·Lat_ROU], [0000] in which the latitude calculated on the basis of the ground locating system is denoted Lat_ROU and the latitude calculated on the basis of the in-flight locating system is denoted Lat_VOL and in which PCT_VOL represents the percentage of the weighting of the position obtained from the in-flight locating system.", "[0037] Advantageously, the longitude of the aircraft, in the transition phase, is determined by the relation: [0000] Long(aircraft)=[PCT_VOL×Long_VOL]+[(100−PCT_VOL)×Long_ROU], [0000] in which the longitude calculated on the basis of the ground locating system is denoted Long_ROU and the latitude calculated on the basis of the in-flight locating system is denoted Long_VOL, and in which PCT_VOL represents the percentage of the weighting of the position obtained from the in-flight locating system.", "[0038] Advantageously, the percentage of the first position (PCT_ROU) and the percentage of the second position (PCT_VOL) are determined on the basis of an altitude-dependent linear relation.", "[0039] Advantageously, the latitude and the longitude of the current position of the aircraft are determined by the following relations: [0000] LAT  ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL ,  LONG ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0000] in which ALT(AS) is the altitude at the point from which the position of the aircraft is entirely calculated on the basis of the in-flight locating system and LAT(aeroplane) is the current altitude of the aircraft.", "[0040] Advantageously, the percentage of the first position (PCT_ROU) and the percentage of the second position (PCT_VOL) are determined on the basis of a time-dependent linear relation.", "[0041] Advantageously, the latitude and the longitude of the current position of the aircraft are determined by the following relations: [0000] LAT  ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LAT_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LAT_VOL ,  LONG ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LONG_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LONG_VOL , [0000] in which Ts is the time of passage at the point from which the position of the aircraft is entirely calculated on the basis of the in-flight locating system, T 0 is the time of passage when the aircraft leaves the runway and T(aeroplane) is the local time of the aircraft.", "[0042] Still other objects and advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein the preferred embodiments of the invention are shown and described, simply by way of illustration of the best mode contemplated of carrying out the invention.", "As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious aspects, all without departing from the invention.", "Accordingly, the drawings and description thereof are to be regarded as illustrative in nature, and not as restrictive.", "BRIEF DESCRIPTION OF THE DRAWINGS [0043] The present invention is illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout and wherein: [0044] FIG. 1A : a diagram of the data making it possible to implement the first step of the first method according to the invention;", "[0045] FIG. 1B : a diagram illustrating the principle of realigning of the positioning of an aircraft on a take-off runway according to the first inventive method;", "[0046] FIG. 2 : an example of hybridization of the locating of the aircraft in the transitional take-off phase;", "[0047] FIG. 3 : the diagram of the data used to hybridize the locating of the aircraft.", "DETAILED DESCRIPTION OF THE INVENTION [0048] The invention makes it possible to optimize the calculation of the position of the aircraft notably by a first method corresponding to the take-off phase and a second method corresponding to the landing phase, the inventive concepts of the two methods being the same.", "[0049] During the take-off phase, a first method according to the invention comprises several steps.", "[0050] A first step of the first method consists in automatically readjusting, before throttle-up, the theoretical take-off position in the onboard computer.", "The theoretical take-off position is generally designated on preparation of the flight by the crew.", "[0051] In the preparation of the flight generally performed in the parking area, the pilot initializes, through the onboard computer, the inertial units and the current position of the aircraft.", "The crew has to select an access ramp to the runway or at least one element of the airport database in order to define the runway entry point.", "[0052] The take-off comprises a rolling phase and a flight phase.", "The rolling of the aircraft prior to take-off proceeds from the initialization of the flight until the moment when the aircraft leaves the runway.", "[0053] The rolling itself comprises a first rolling phase of the initialization of the flight until the moment of throttle-up and an acceleration phase on the runway between throttle-up and the moment when the aircraft leaves the runway.", "[0054] The method according to the invention makes it possible to establish in this first step an automatic realigning in the computer of the take-off position actually measured based on the ground locating system.", "[0055] FIG. 1A represents a schematic view of a runway 1 and of two access ramps B 1 , B 2 .", "In the example of FIG. 1A , the crew has previously selected ramp B 1 so as to be positioned on the theoretical take-off position 3 .", "[0056] From the airport database and the selected element B 1 , the computer determines the point of intersection 2 of the ramp B 1 and the runway 1 and the theoretical take-off point 3 .", "[0057] The theoretical take-off point of the runway generated by the computer is situated at a distance from the point of intersection 2 calculated so that the aircraft can perform its final turning before the take-off and be positioned facing the runway.", "This final point of the runway generated in this way from the selection of the element by the crew is called the “theoretical take-off point.”", "[0058] In reality, the aircraft is rarely exactly placed at the theoretical take-off point generated by the computer, and can be more or less offset from this position.", "In the example of FIG. 1A , the aircraft is situated at a position 4 when stopped and is ready for throttling-up.", "[0059] The invention makes it possible, based on the ground locating system, to measure the actual position 4 of the aircraft and automatically update this actual take-off position in the computer so that this final value replaces the theoretical position 3 .", "[0060] The calculation of this offset is performed from the computer and the database of the airport elements which comprises the coordinates and the geometrical shapes, notably of the runways, of the runway thresholds, of the runway axes, of the access ramps, of the access ramp axes, of the intersections between the taxiways and the runways and the intersections between runways themselves, and of the specific markings on the runways.", "[0061] The theoretical take-off point generated in this way following the selection of an element by the crew is the point of the take-off runway that presents the highest probability of the aircraft being positioned there.", "The aircraft has previously used the element of the airport selected by the crew.", "[0062] For this, a mapping rule associates an element of the database of airport elements with a determined point of the runway that is optimal for the take-off, i.e. the theoretical take-off point.", "[0063] In the phase of positioning of the aircraft on the take-off runway, the onboard computer detects at regular intervals if the aircraft is in the take-off situation, generally the aircraft is stopped in this situation and the crew is preparing to throttle up.", "This final situation is recorded by a condition, denoted take-off condition.", "[0064] When the take-off condition is validated, the deviation between the theoretical take-off position and the actually measured position of the aircraft by the ground locating system is measured.", "When the value of the measured deviation is situated above a tolerance threshold, the computer realigns the position of the aircraft on the actually measured position.", "Below the threshold, the value of the theoretical take-off position is maintained in the computer.", "[0065] FIG. 1B represents a Computer K, such as an ANS, having calculated a take-off point “PT_take-off”", "from the selection, by the crew, of an element of the airport database, called “database airport”", "in FIG. 1B .", "[0066] The method according to the invention therefore makes it possible to compare the position of the take-off point PT_take-off with the current position of the aircraft, the latter being measured on the basis of the ground locating system.", "[0067] The current position, measured by the ground locating system SYS_LOC_SOL, is accompanied by an uncertainty margin linked to the context of the aircraft and to the locating system.", "[0068] If the “take-off”", "condition is validated, that is, the aircraft is stopped and the throttling-up can be performed, then, according to the value of the difference of the measured positions between the take-off point and the current position of the aircraft, an automatic realignment of the take-off point is performed in the FMS, an offset generally called “take-off shift.”", "This realignment makes it possible to update the computer so that the initial take-off point is a correct point supplied to the in-flight locating system.", "[0069] The automatic realignment of the take-off position is carried out for a value of the difference of the measured positions that exceeds a predetermined threshold.", "This final threshold value takes into account the uncertainty margins measured by the aircraft position detection equipment.", "[0070] The second step of the method is performed in the acceleration phase of the aircraft on the take-off runway between the moment of throttling-up and the moment when the aircraft leaves the runway and is no longer in contact with the runway.", "[0071] In this step, the position of the aircraft is entirely measured from the ground locating system, the latter being handled by a system of sensors of GPS and/or IRS type with a local augmentation system of GBAS type and possibly using a multilateration based on antennas fixed to the ground, the positions of which are known.", "[0072] FIG. 2 represents the distribution of the weighting of the measurements of the positions (LOC_SOL, LOC_VOL) of the aircraft by the ground locating system and by the in-flight locating system during the take-off phase.", "[0073] The weighting of the measurements in the method according to the invention is different depending on whether the aircraft is in one of the three distinct phases represented: acceleration, take-off or the transition phase and a final flight phase, denoted stabilization phase.", "[0074] The position of the aircraft, throughout the acceleration phase, is contained in the part 20 of the curve between the take-off point, represented by the origin of the graph, and the point where the aircraft leaves the runway, represented by the point A 0 .", "[0075] A third step of the method, following the acceleration of the aircraft, comprises the calculation of at least one position between the point A 0 where the aircraft leaves the runway and a threshold point As from which the position of the aircraft is entirely measured based on the in-flight locating system.", "[0076] FIG. 2 represents, in the part 21 of the curve between the point A 0 and the point AS, a linear hybridization between the measurement of the position of the aircraft by the ground locating system and the measurement of the position by the in-flight locating system.", "[0077] The method according to the invention makes it possible to have several indicators to determine the point A 0 .", "This final point can be determined after the rotation of the aircraft, involving a crossed altitude condition above the take-off runway or even by an indicator of the overshooting of a pressure threshold on the landing gears.", "As an example, the altitude condition of the point A 0 can be obtained for an altitude threshold above the runway of 10 feet.", "[0078] The point AS is considered as a threshold position that no longer requires the accuracy of the ground locating system.", "This final position can be determined in several ways depending on the embodiments.", "The altitude condition of the point AS can be obtained for a predetermined altitude threshold above the ground;", "it could for example be 50 feet.", "[0079] In another embodiment, the point AS can be determined by a condition of a crossed rolling threshold, that is, after the aircraft has performed a turn.", "[0080] A variant embodiment of the invention makes it possible to determine the point AS from a delay corresponding to a predetermined time after throttling-up.", "[0081] During this transition phase following take-off, when the aircraft has left the runway, the invention proposes to measure, in this step, the position of the aircraft by a weighting expressed as a percentage of a first position, denoted PCT ROU, determined on the basis of the ground locating system and a second position, denoted PCT VOL, determined on the basis of the in-flight locating system.", "[0082] This weighting can be a function of the altitude, of the speed or of the roll of the aircraft or even a combination of these data.", "The weighting can also be carried out for predetermined period of time, for example from the moment of throttling-up.", "[0083] The curve linking the two positions deriving from their respective locating system may be linear or indeed non-linear.", "In the latter case, it may be a curve of the second degree or logarithmic for example, or even any other basic function.", "[0084] An exemplary implementation of hybridization based on a weighting of the location of the aircraft according to the positions of each locating system makes it possible to equally determine the latitude, denoted Lat(aeroplane), and the longitude, denoted Long(aeroplane), of the aircraft by the following relations: [0000] LAT(aeroplane)=[PCT_VOL*LAT_VOL]+[(100%−PCT_VOL)*LAT_ROU];", "[0000] in which the latitude calculated on the basis of the ground locating system is denoted LAT_ROU and the latitude calculated on the basis of the in-flight locating system is denoted LAT_VOL;", "and [0000] LONG(aeroplane)=[PCT_VOL*LONG_VOL]+[(100%−PCT_VOL)*LONG_ROU];", "[0000] in which the longitude calculated on the basis of the ground locating system is denoted LONG_ROU and the longitude calculated on the basis of the in-flight locating system is denoted LONG_VOL.", "[0085] FIG. 2 represents a linear slope between A 0 and AS where the hybridization of the positions LOC_SOL and LOC_VOL is performed according to the altitude.", "The percentages PCT_VOL and PCT_ROU corresponding to the hybridization of the positions deriving from the in-flight and ground locating systems are therefore functions of the altitude.", "[0086] In the example, the relation, linking the positions LOC_SOL and LOC_VOL with the altitude, is linear between the points A 0 and AS.", "ALT(aeroplane) represents the instantaneous altitude of the aircraft and ALT(AS) represents the altitude at the point AS.", "[0087] The relations then become: [0000] LAT  ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL LONG ( Aeroplane ) = ALT  ( AS ) - ALT  ( aeroplane ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0000] in which the latitude calculated on the basis of the ground locating system is denoted LAT_ROU and the latitude calculated on the basis of the in-flight locating system is denoted LAT_VOL;", "and In which the longitude calculated on the basis of the ground locating system is denoted LONG_ROU and the longitude calculated on the basis of the in-flight locating system is denoted LONG_VOL.", "[0088] In this final example, after the passage at the point AS, the altitude, called “threshold altitude”, the calculation of the position of the aircraft is performed solely by the in-flight locating system.", "[0089] The following then apply: PCT_ROU=0% and PCT_VOL=100%.", "[0090] In another embodiment, the percentages PCT_VOL and PCT_ROU corresponding to the hybridization of the positions deriving from the in-flight and ground locating systems are functions of time.", "T(aeroplane) is used to denote the local time of the aircraft expressed in seconds, Ts the planned time at which the aircraft uses only its in-flight locating system corresponding to the point AS, and T 0 the time, expressed in seconds, at which the aircraft leaves the runway, this point corresponding to the point A 0 in FIG. 2 .", "[0091] The relations then become: [0000] LAT  ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LAT_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LAT_VOL LONG ( Aeroplane ) = Ts - T  ( aeroplane ) Ts - T   0 · LONG_ROU + T  ( aeroplane ) - T   0 Ts - T   0 · LONG_VOL [0092] When the time Ts has elapsed, the position of the aircraft uses 100% of the position deriving from the in-flight locating system.", "[0093] A second method makes it possible to calculate, on the basis of a hybridization similar to that used on take-off, the position of the aircraft when the latter is in the approach phase.", "An altitude, time or flying mode threshold condition, for example on final levelling-off, makes it possible to determine a hybrid calculation mode.", "[0094] Until the condition is reached, that is, the aircraft is in cruising flight mode and upstream of the final approach phase, the position of the aircraft is entirely determined on the basis of the in-flight locating system.", "[0095] In the final transitional approach phase, a hybridization of the calculation of the position of the aircraft between the position deriving from the in-flight locating system and from the ground locating system can be determined as a function of the altitude.", "[0000] The relations are as follows: [0000] LAT  ( Aeroplane ) = ALT  ( aeroplane ) - ALT  ( AS ) ALT  ( AS ) · LAT_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LAT_VOL LONG ( Aeroplane ) = ALT  ( aeroplane ) - ALT  ( AS ) ALT  ( AS ) · LONG_ROU + ALT  ( aeroplane ) ALT  ( AS ) · LONG_VOL [0096] In the same way as in the take-off phase, a variant embodiment makes it possible to implement a method in which the hybridization of the position of the aircraft is a function of time.", "[0097] Finally, when the aircraft makes contact with the runway, this condition being determined by a measurement of the altitude or of a pressure of the landing gears for example, the position of the aircraft is then entirely determined on the basis of the ground locating system, as well as during the rolling phases preceding the landing.", "[0098] FIG. 3 represents the principle of hybridization of the position of the aircraft based on the data obtained from the aircraft computer.", "LOC VOL represents the position deriving from the in-flight locating system, LOC SOL represents the position deriving from the ground locating system.", "The hybridization between the two measured positions is checked and performed on the basis of the data associated with the context of the aircraft: the time determined by the computer clock, the pressure of the landing gear by sensors positioned on the aircraft, the altitude, the roll and the speed determined on the basis of the aircraft's onboard computer.", "The computer is then capable of determining a hybridized position in the take-off and approach phases.", "[0099] It will be readily seen by one of ordinary skill in the art that the present invention fulfils all of the objects set forth above.", "After reading the foregoing specification, one of ordinary skill in the art will be able to affect various changes, substitutions of equivalents and various aspects of the invention as broadly disclosed herein.", "It is therefore intended that the protection granted hereon be limited only by definition contained in the appended claims and equivalents thereof." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process, composition and use of marking bodies for marking and identifying pourable materials. 2. Description of the Prior Art It is frequently desired to mark or identify the origin and quality of pourable materials which are frequently used in large quantities and which can be natural substances. For this purpose records can be made, or e.g. plates can be prepared on which corresponding record entries are made. This is relatively complicated and disadvantageous, because such records or plates can be lost. Even with the aid of detailed descriptions of such materials on delivery notes and/or invoices or packings, the problem is still not solved. Thus, for example, in the case of greened areas, and in particular on roofs, use is made of substrates, drainage bulk and filling materials of different qualities, which are based on specific starting material, formulations and production processes. In general building planners, architects or contractors are not in a position to evaluate the quality or origin of the materials used. The obvious appearance or characteristics establishable by manual samples generally differs, sometimes even between individual batches, due to the varying appearances of natural materials, different origins and frequently changing moisture contents. However, it is virtually indispensable for the responsible parties to establish on delivery and installation whether the requested quality has also been supplied and installed, particularly as architects have a long-term planning responsibility. A contractor must be able to expect that the promised characteristics or effects are actually obtained. Objectively, up to now, the characteristics or properties of such substrates or materials have only been possible by analysis at specialized institutes or laboratories. However, the testing methods can last several weeks or months and lead to costs which can exceed the material price, depending on the object size. Obviously, high-quality substrates and drainage bulk materials are much more expensive than those with a lower quality. It is therefore clear that it is advantageous and important to be able to rapidly and easily distinguish such pourable materials on the basis of their origin and/or quality. Thus, even after purchase has taken place and independently of whether supplied loose or in packed form and both at the time of use or installation and at a distant time, it is possible to establish from where they come and that their action has not been impaired, although their overall appearance may have been considerably changed. This problem is solved according to the process of the invention by the use of a marking body within a substrate material. In addition, the present invention can also be described as the use of one or more natural or synthetic, not difficultly or easily degradable or decomposable foreign bodies for marking and identifying pourable substances or materials which can be differentiated visibly as a result of their colors, consistency or some other property from the loose or bulk materials to be identified, without impairing the function of the latter. SUMMARY OF THE INVENTION The invention provides a process for marking and identifying loose, pourable materials to indicate their origin or quality which by adding one or more marking bodies to the pourable material to form a mixture. The marking bodies have a color, consistency or other visibly identifiable property different from the loose, pourable materials to be identified. The presence of the marking bodies in the mixture does not impair the use of the mixture to form an element as compared to a similar element formed from the pourable materials without the marking bodies. The origin or quality of the pourable materials can be identified at a point in time after the formation of the mixture and after the formation of an element with the mixture. The pourable materials comprise one or more components selected from the group consisting of peat, compost, humus, clay, lava, pumice-stone, sand, fertilizers, soil stabilizers, soil improving substances, recycled soil substances, soil drainage substances and soil fillers. The invention also provides a composition capable of such identification. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The invention provides a simple and clean process which can be rapidly and inexpensively performed and which permits the identification of bulk material on delivery and installation, and optionally also after several years, so that its origin and quality can be reliably determined. Obviously, only sufficient foreign or marking bodies are used as permit an identification within an appropriate interval of time, without having to be excessively sought. As these marking bodies may be synthetic and not or only difficulty decomposable and are only present in very small quantities, they do not impair the function of the pourable material. It is also logical that these marking bodies must differ with respect to their color, consistency or some other property from the pourable materials, so that they can be easily detected. If a certain number of marking bodies are added per m 3 , they are recognizable on delivery and installation on the bulk material surface. In addition, at any random time they can be made to appear by spreading the bulk material over a larger surface so that, calculated per m 2 they can be made visible on the surface and permit a reliable identification. In the preferred embodiment the marking bodies may have a diameter of from about 2 to about 10 mm and a thickness of from about 1 to about 10 mm. The marking bodies may comprise a natural or synthetic material which is or is not easily degradable by weathering or biodegradability. Synthetic materials include plastics. When using such pourable materials it can also be advantageous to only have such marking bodies in materials at the time of delivery for a few days or weeks after the installation or incorporation of such materials. Suitable materials for such rapidly or medium-term degradable or decomposable marking bodies are e.g. paper, board or wood, which can be degraded in a few days or weeks as a function of the temporary moisture content of the bulk material. It would also be conceivable to produce such marking bodies from corn or potato starch. Thus, for example, in the pharmaceutical industry, there are numerous tablets, which dissolve rapidly before or after ingestion and which largely consist of starch as the carrier. As a function of the size of the marking body and the binders used, such marking bodies will also decompose within a few hours, days, or weeks. An example of the medium-term stability of such marking bodies, e.g. made from starch are the "putting inserts" used in golf. It is required that these inserts reliably decompose within one vegetation period or one year. It is obvious that the probability of identification is increased with a rising number of marking bodies. Further advantages and features which in particular relate to the nature of the pourable materials, the quantity of the marking bodies and their structure or design are part of the invention. The marking bodies may have the shape of the logo, trademark or flower and which ensure good marking and identifying possibilities. Examples of the invention are described in greater detail hereinafter. The pourable materials or substrates can contain one or more of the following constituents: peat, bark humus, so-called top soil or subsoil, lava, limestone fines or chips, pumice, expanded clay, expanded shale, mineral or organic recycling substances, vermiculite, fertilizers, other action improving agents, etc. Obviously the substrates can have different compositions in accordance with the most varied fields of use, such as for intense greened roof areas, plant containers for very high plant demands, extensively greened roof areas with demanding vegetation, as well as with lower plant demands. The invention can be used as well as for greening underground car parks with substrate thickness of approximately 25 to 50 cm, or as a filling substrate layer under an underground car park substrate as from a depth of about 50 cm. The invention can be used as well as a tree substrate for top quality avenue trees and at isolated locations. A useful tree hole depth is approximately 40 to about 180 cm tree hole depth. The composition can be used for peat bed substrates for soils for special demands, e.g. of azaleas and rhododendrons or for vegetation forms with very different demands. The composition can be used as container substrates for raising plants in pots and nurseries, larger isolated containers, as well as for drainage material for rapidly draining away excess water whilst at the same time storing plant-available water in drainage layers. All the substrates and materials are so adjusted by special formulations that they meet the particular use requirement and offer optimum growth conditions for the particular plant types. The invention is not restricted to the aforementioned pourable materials and can instead be used in wider technical fields, if such materials have to be marked and subsequently identified, such as can e.g. be the case with chemical products, detergent or concrete aggregates. In the following three Tables 1 to 3, in each case, a certain number of mixing tests with different loose, pourable, earth substrate materials are given and to which are added a varying number of green marking bodies in the form of crushed, expanded clay granules with a diameter of 6 to 10 mm. One hundred such green marking bodies have a weight of approximately 17 grams. However, for the expert other weights and shapes are conceivable for the marking bodies according to the invention. However, it is readily apparent that it is also possible to use different colored marking bodies, also made from different materials and in different sizes and which can still act in accordance with the invention. For this purpose 100 or 60 liters of substrate are fed into a mixing drum, to which are subsequently added the marking body quantities given in the tables. The mixing drums are then rotated for about 10 minutes in order to simulate the substrate production process, so that a good mixing of the marking bodies with the particular substrate is ensured. The mixture is then completely transferred into a 1 m 2 box whose side edge height is 15 cm. Using a wood lath the mixture surface is flattened. Determination then takes place by counting of the number of marking bodies which are visible and this is given in the tables. In a further process step the mixture is watered from above with a hose sprinkler in order to produce or simulate natural conditions, such as e.g. rain. Subsequently determination takes place by counting of the number of marking bodies which are now visible. The values are given in the tables. TABLE 1______________________________________Optima Intensive Substrate Type I/01 for IntensiveRoof Greened Areas. Marking Visible/ Visible/ bodies dry watered Added No./m.sup.2 No./m.sup.2______________________________________1.1 100 1 Substrate 25 1 31.2 100 1 Substrate 50 4 51.3 100 1 Substrate 100 7 131.4 100 1 Substrate 200 11 21______________________________________ TABLE 2______________________________________Optima Underground Car Park Substrate Type H 0/25 Marking Visible/ Visible/ bodies dry watered Added No./m.sup.2 No./m.sup.2______________________________________2.1 100 1 Substrate 100 7 122.2 100 1 Substrate 200 13 29______________________________________ TABLE 3______________________________________Optima Mineral Substrate Type M2/10 (Expanded Clay Bodies) Marking Visible/ Visible/ bodies dry watered Added No./m.sup.2 No./m.sup.2______________________________________3.1 60 1 Substrate 15 4 43.2 60 1 Substrate 30 6 83.3 60 1 Substrate 60 10 113.4 60 1 Substrate 120 16 16______________________________________ It is obvious that if a large number of marking bodies are used, such as is the case with tests 1.3, 1.4, 2.1, 2.2, and 3.3 and 3.4, a corresponding large number of marking bodies can be identified on the surface of the subsequently spread out material. Thus, from the practical standpoint with approximately 100 liters of substrate, 25 marking bodies should be adequate because test 1.1 shows that subsequently 1 or 3 per m 2 are visible. In the case of the substrates in question, the test quantity of 25 bodies per 100 1 of substrate is adequate. Mathematically it can be gathered therefrom that for 1 m 3 (=100 1) 250 marking bodies lead to a sensible result. However, according to the invention the numbers can also be reduced, e.g. to 100 marking bodies/m 3 , provided that the subsequent identification work is not too tiresome. Values below 100 marking bodies/m 3 are therefore also conceivable. From about 10 to about 100 marking bodies added to the mixture per m 3 of pourable materials is preferred. However, it is naturally undesirable to add too many marking bodies to the substrates or loose, pourable materials, because this leads to additional costs and possible to an undesirable appearance. Therefore, for the aforementioned substrates, an upper limit of 1000 marking bodies/m 3 appears suitable. However, this value does not constitute a clearly defined upper limit, because loose, pourable materials with other characteristics may make necessary different numbers of marking bodies. However, the expert can easily establish the desired quantity of marking bodies by a few tests.
A composition and process for identifying the origin or quality of loose, pourable materials by mixing the materials with one or more marking bodies which have a color, consistency or other visibly identifiable property different from the pourable materials. The marking bodies in the mixture do not impair the intended use of the pourable materials. The origin or quality of the pourable materials can be identified at a point in time distant from the forming of the mixture and even after manufacturing article with the mixture. The pourable materials can be peat, compost, humus, clay, lava, pumice-stone, sand, fertilizers, soil stabilizers, soil improving substances, recycled soil substances, soil drainage substances and soil fillers.
Summarize the key points of the given document.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The invention relates to a process, composition and use of marking bodies for marking and identifying pourable materials.", "Description of the Prior Art It is frequently desired to mark or identify the origin and quality of pourable materials which are frequently used in large quantities and which can be natural substances.", "For this purpose records can be made, or e.g. plates can be prepared on which corresponding record entries are made.", "This is relatively complicated and disadvantageous, because such records or plates can be lost.", "Even with the aid of detailed descriptions of such materials on delivery notes and/or invoices or packings, the problem is still not solved.", "Thus, for example, in the case of greened areas, and in particular on roofs, use is made of substrates, drainage bulk and filling materials of different qualities, which are based on specific starting material, formulations and production processes.", "In general building planners, architects or contractors are not in a position to evaluate the quality or origin of the materials used.", "The obvious appearance or characteristics establishable by manual samples generally differs, sometimes even between individual batches, due to the varying appearances of natural materials, different origins and frequently changing moisture contents.", "However, it is virtually indispensable for the responsible parties to establish on delivery and installation whether the requested quality has also been supplied and installed, particularly as architects have a long-term planning responsibility.", "A contractor must be able to expect that the promised characteristics or effects are actually obtained.", "Objectively, up to now, the characteristics or properties of such substrates or materials have only been possible by analysis at specialized institutes or laboratories.", "However, the testing methods can last several weeks or months and lead to costs which can exceed the material price, depending on the object size.", "Obviously, high-quality substrates and drainage bulk materials are much more expensive than those with a lower quality.", "It is therefore clear that it is advantageous and important to be able to rapidly and easily distinguish such pourable materials on the basis of their origin and/or quality.", "Thus, even after purchase has taken place and independently of whether supplied loose or in packed form and both at the time of use or installation and at a distant time, it is possible to establish from where they come and that their action has not been impaired, although their overall appearance may have been considerably changed.", "This problem is solved according to the process of the invention by the use of a marking body within a substrate material.", "In addition, the present invention can also be described as the use of one or more natural or synthetic, not difficultly or easily degradable or decomposable foreign bodies for marking and identifying pourable substances or materials which can be differentiated visibly as a result of their colors, consistency or some other property from the loose or bulk materials to be identified, without impairing the function of the latter.", "SUMMARY OF THE INVENTION The invention provides a process for marking and identifying loose, pourable materials to indicate their origin or quality which by adding one or more marking bodies to the pourable material to form a mixture.", "The marking bodies have a color, consistency or other visibly identifiable property different from the loose, pourable materials to be identified.", "The presence of the marking bodies in the mixture does not impair the use of the mixture to form an element as compared to a similar element formed from the pourable materials without the marking bodies.", "The origin or quality of the pourable materials can be identified at a point in time after the formation of the mixture and after the formation of an element with the mixture.", "The pourable materials comprise one or more components selected from the group consisting of peat, compost, humus, clay, lava, pumice-stone, sand, fertilizers, soil stabilizers, soil improving substances, recycled soil substances, soil drainage substances and soil fillers.", "The invention also provides a composition capable of such identification.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The invention provides a simple and clean process which can be rapidly and inexpensively performed and which permits the identification of bulk material on delivery and installation, and optionally also after several years, so that its origin and quality can be reliably determined.", "Obviously, only sufficient foreign or marking bodies are used as permit an identification within an appropriate interval of time, without having to be excessively sought.", "As these marking bodies may be synthetic and not or only difficulty decomposable and are only present in very small quantities, they do not impair the function of the pourable material.", "It is also logical that these marking bodies must differ with respect to their color, consistency or some other property from the pourable materials, so that they can be easily detected.", "If a certain number of marking bodies are added per m 3 , they are recognizable on delivery and installation on the bulk material surface.", "In addition, at any random time they can be made to appear by spreading the bulk material over a larger surface so that, calculated per m 2 they can be made visible on the surface and permit a reliable identification.", "In the preferred embodiment the marking bodies may have a diameter of from about 2 to about 10 mm and a thickness of from about 1 to about 10 mm.", "The marking bodies may comprise a natural or synthetic material which is or is not easily degradable by weathering or biodegradability.", "Synthetic materials include plastics.", "When using such pourable materials it can also be advantageous to only have such marking bodies in materials at the time of delivery for a few days or weeks after the installation or incorporation of such materials.", "Suitable materials for such rapidly or medium-term degradable or decomposable marking bodies are e.g. paper, board or wood, which can be degraded in a few days or weeks as a function of the temporary moisture content of the bulk material.", "It would also be conceivable to produce such marking bodies from corn or potato starch.", "Thus, for example, in the pharmaceutical industry, there are numerous tablets, which dissolve rapidly before or after ingestion and which largely consist of starch as the carrier.", "As a function of the size of the marking body and the binders used, such marking bodies will also decompose within a few hours, days, or weeks.", "An example of the medium-term stability of such marking bodies, e.g. made from starch are the "putting inserts"", "used in golf.", "It is required that these inserts reliably decompose within one vegetation period or one year.", "It is obvious that the probability of identification is increased with a rising number of marking bodies.", "Further advantages and features which in particular relate to the nature of the pourable materials, the quantity of the marking bodies and their structure or design are part of the invention.", "The marking bodies may have the shape of the logo, trademark or flower and which ensure good marking and identifying possibilities.", "Examples of the invention are described in greater detail hereinafter.", "The pourable materials or substrates can contain one or more of the following constituents: peat, bark humus, so-called top soil or subsoil, lava, limestone fines or chips, pumice, expanded clay, expanded shale, mineral or organic recycling substances, vermiculite, fertilizers, other action improving agents, etc.", "Obviously the substrates can have different compositions in accordance with the most varied fields of use, such as for intense greened roof areas, plant containers for very high plant demands, extensively greened roof areas with demanding vegetation, as well as with lower plant demands.", "The invention can be used as well as for greening underground car parks with substrate thickness of approximately 25 to 50 cm, or as a filling substrate layer under an underground car park substrate as from a depth of about 50 cm.", "The invention can be used as well as a tree substrate for top quality avenue trees and at isolated locations.", "A useful tree hole depth is approximately 40 to about 180 cm tree hole depth.", "The composition can be used for peat bed substrates for soils for special demands, e.g. of azaleas and rhododendrons or for vegetation forms with very different demands.", "The composition can be used as container substrates for raising plants in pots and nurseries, larger isolated containers, as well as for drainage material for rapidly draining away excess water whilst at the same time storing plant-available water in drainage layers.", "All the substrates and materials are so adjusted by special formulations that they meet the particular use requirement and offer optimum growth conditions for the particular plant types.", "The invention is not restricted to the aforementioned pourable materials and can instead be used in wider technical fields, if such materials have to be marked and subsequently identified, such as can e.g. be the case with chemical products, detergent or concrete aggregates.", "In the following three Tables 1 to 3, in each case, a certain number of mixing tests with different loose, pourable, earth substrate materials are given and to which are added a varying number of green marking bodies in the form of crushed, expanded clay granules with a diameter of 6 to 10 mm.", "One hundred such green marking bodies have a weight of approximately 17 grams.", "However, for the expert other weights and shapes are conceivable for the marking bodies according to the invention.", "However, it is readily apparent that it is also possible to use different colored marking bodies, also made from different materials and in different sizes and which can still act in accordance with the invention.", "For this purpose 100 or 60 liters of substrate are fed into a mixing drum, to which are subsequently added the marking body quantities given in the tables.", "The mixing drums are then rotated for about 10 minutes in order to simulate the substrate production process, so that a good mixing of the marking bodies with the particular substrate is ensured.", "The mixture is then completely transferred into a 1 m 2 box whose side edge height is 15 cm.", "Using a wood lath the mixture surface is flattened.", "Determination then takes place by counting of the number of marking bodies which are visible and this is given in the tables.", "In a further process step the mixture is watered from above with a hose sprinkler in order to produce or simulate natural conditions, such as e.g. rain.", "Subsequently determination takes place by counting of the number of marking bodies which are now visible.", "The values are given in the tables.", "TABLE 1______________________________________Optima Intensive Substrate Type I/01 for IntensiveRoof Greened Areas.", "Marking Visible/ Visible/ bodies dry watered Added No./m.", "sup[.", "].2 No./m.", "sup[.", "].2______________________________________1.1 100 1 Substrate 25 1 31.2 100 1 Substrate 50 4 51.3 100 1 Substrate 100 7 131.4 100 1 Substrate 200 11 21______________________________________ TABLE 2______________________________________Optima Underground Car Park Substrate Type H 0/25 Marking Visible/ Visible/ bodies dry watered Added No./m.", "sup[.", "].2 No./m.", "sup[.", "].2______________________________________2.1 100 1 Substrate 100 7 122.2 100 1 Substrate 200 13 29______________________________________ TABLE 3______________________________________Optima Mineral Substrate Type M2/10 (Expanded Clay Bodies) Marking Visible/ Visible/ bodies dry watered Added No./m.", "sup[.", "].2 No./m.", "sup[.", "].2______________________________________3.1 60 1 Substrate 15 4 43.2 60 1 Substrate 30 6 83.3 60 1 Substrate 60 10 113.4 60 1 Substrate 120 16 16______________________________________ It is obvious that if a large number of marking bodies are used, such as is the case with tests 1.3, 1.4, 2.1, 2.2, and 3.3 and 3.4, a corresponding large number of marking bodies can be identified on the surface of the subsequently spread out material.", "Thus, from the practical standpoint with approximately 100 liters of substrate, 25 marking bodies should be adequate because test 1.1 shows that subsequently 1 or 3 per m 2 are visible.", "In the case of the substrates in question, the test quantity of 25 bodies per 100 1 of substrate is adequate.", "Mathematically it can be gathered therefrom that for 1 m 3 (=100 1) 250 marking bodies lead to a sensible result.", "However, according to the invention the numbers can also be reduced, e.g. to 100 marking bodies/m 3 , provided that the subsequent identification work is not too tiresome.", "Values below 100 marking bodies/m 3 are therefore also conceivable.", "From about 10 to about 100 marking bodies added to the mixture per m 3 of pourable materials is preferred.", "However, it is naturally undesirable to add too many marking bodies to the substrates or loose, pourable materials, because this leads to additional costs and possible to an undesirable appearance.", "Therefore, for the aforementioned substrates, an upper limit of 1000 marking bodies/m 3 appears suitable.", "However, this value does not constitute a clearly defined upper limit, because loose, pourable materials with other characteristics may make necessary different numbers of marking bodies.", "However, the expert can easily establish the desired quantity of marking bodies by a few tests." ]
CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 12/618,772, filed Nov. 15, 2009, which is a continuation of U.S. patent application Ser. No. 11/424,659, filed Jun. 16, 2006, now U.S. Pat. No. 7,631,145, which claims the benefit of U.S. Provisional Patent Application No. 60/693,987, filed Jun. 23, 2005, which are incorporated by reference. BACKGROUND OF THE INVENTION Typical cache designs provide a dedicated area of memory to separately store a subset of a larger portion of data in memory. By storing data that is likely to be accessed again in the future in the dedicated area of memory, which may be more quickly or otherwise more efficiently accessed, overall efficiency of data access may be greatly improved. An underlying assumption of typical cache designs is locality of access, which refers to the likelihood that data accessed at one point in time is likely to be accessed again. If the subset of data stored in the dedicated memory area is likely to be accessed again in the future, the cache may be capable of achieving high levels of efficiency. On the other hand, if the subset of data stored in the dedicated memory area is not likely to be accessed again in the future, the cache is unlikely to achieve an acceptable measure of efficiency. In many computer systems, only a limited amount of dedicated memory area may be available for implementing a cache system. Depending on the nature of the data to be accessed, the limited amount of dedicated memory area may be insufficient to provide an efficient cache system following traditional cache designs. For example, one type of data that has potential for utilizing efficient caching is graphics data such as texel data to be accessed from memory by a graphics processing system and rendered on a display. From one frame to the next, there may be a high degree of locality of access. In other words, a high number of the memory locations accessed to retrieve texel data for the current frame rendered on the display may be accessed again to retrieve the same texel data for the next frame rendered on the display. This may often be the case, for instance, in situations where the rendered image remains largely unchanged from one frame to the next. Such locality of access from one frame to the next frame presents a potential for implementation of an efficient cache system. However, a prohibitively large amount of dedicated memory area may be required to exploit such locality of access, when traditional cache designs are utilized. In this example, the locality of access exists across frames. That is, a piece of texel data that is currently accessed is likely to be accessed again, but not until the next frame. Here, a traditional cache design that updates cache memory with the most recently accessed data may require enough dedicated memory area to provide caching for a full frame worth of texel data accesses, in order for the cache to perform properly. Otherwise, the cache may run out of memory space and begin overwriting useful cache entries stored from the current frame, before those cache entries are ever accessed in the next frame. Thus, cache entries that would have produced “hits” (a data access request that result in a match in the cache) in such a system may be destroyed prematurely, leading to an extremely low “hit rate” (ratio of data access requests that result in a match in the cache). FIG. 1 is a block diagram of an illustrative computer system 100 containing memory components for which efficient data caching may be employed. As shown, computer system 100 includes a graphics card 102 , a central processing unit (CPU) 104 , a chipset comprising a northbridge chip 106 and a southbridge chip 108 , system memory 110 , PCI slots 112 , disk drive controller 114 , universal serial bus (USB) connectors 116 , audio CODEC 118 , a super I/O controller 120 , and keyboard controller 122 . As shown in FIG. 1 , graphics card 102 includes a graphics processing unit (GPU) 124 and local memory 126 . Also, graphics card 102 is connected to a display 128 that may be part of computer system 100 . Here, GPU 124 is a semiconductor chip designed to perform graphics processing operations associated with rendering an image that may be presented on display 128 . Data residing in local memory 126 may be used as input data in the graphics rendering process, which produces a final image for presentation on display 128 . Alternatively or additionally, data residing in system memory 110 may also be used as input data in the graphics rendering process. These accesses to memory performed by GPU 124 may be associated with significant latencies that impact the performance of the system. It may thus be desirable to provide a data caching system so that GPU 124 may access such data in a more efficient manner. However, as discussed above, usage of the large amount of dedicated memory area required for caching data using traditional cache designs may simply be impracticable. For example, a typical graphics processing unit implemented as a semiconductor chip, such as GPU 124 , may have a limited amount of on-chip memory. This may be the case due to a variety of factors, such as manufacturing cost. The amount of dedicated memory area required to provide caching for a full frame worth of texel data accesses, for instance, may simply be too large to fit within the limited on-chip memory associated with the graphics processing unit. One alternative may be to forego the advantages of caching and design the system to accommodate deficiencies such as higher latencies associated with memory accesses without caching. Such a system is likely to incur high area costs associated with the accommodation of high access latency. Another alternative may be to simply implement a traditional cache design using the limited amount of memory area available, even though it may be insufficient to fully exploit the temporal locality of access of the underlying data. As previously mentioned, this likely leads to an inefficient cache characterized by an extremely low hit rate. Such a system is also likely to have inferior memory access performance. Thus, there is an urgent need for an improved cache design capable of utilizing a limited amount of memory area to achieve efficient data caching. BRIEF SUMMARY OF THE INVENTION The present invention relates to methods, apparatuses, and systems for caching data. A cache memory area may be used for storing data from memory locations in an original memory area. The cache memory area may be used in conjunction with a repeatedly updated record of storage associated with the cache memory area. The repeatedly updated record of storage can thus provide a history of data storage associated with the cache memory area. The cache memory area may be loaded with entries previously stored in the cache memory area, by utilizing the repeatedly updated record of storage. In this manner, the record may be used to “warm up” the cache memory area, loading it with data entries that were previously cached and may be likely to be accessed again if repetition of memory accesses exists in the span of history captured by the repeatedly updated record of storage. In one embodiment of the invention, the repeatedly updated record of storage comprises a sequence of first memory allocations, each of the first memory allocations capable of storing a plurality of entries each comprising a tag for referencing a memory location in the original memory area. Further, the cache memory area comprises a sequence of second memory corresponding to a limited range of the sequence of first memory locations, each of the second memory allocations capable of storing a plurality of entries each comprising a data value associated with a memory location in the original memory area. In this embodiment, accesses occur to at least one of the second memory allocations, and the limited range to which the second sequence of memory allocations correspond is advanced by unloading data from one of the second memory allocations and loading one of the second memory allocations with data corresponding to entries stored in a subsequent one of the sequence of first memory allocations. The sequence of second memory allocations may be implemented as on-chip memory within a semiconductor chip containing a system requesting access to a memory location in the original memory area, wherein the sequence of first memory allocations is implemented as off-chip memory that is not part of the semiconductor chip containing the system requesting access to the memory location in the original memory area. The system requesting access may be a graphics processing unit requesting access to texel data stored in the original memory area. In one embodiment of the invention, each of the plurality of entries stored in each of the first memory allocations comprises both a tag for referencing a memory location in the original memory area and a corresponding data value associated with the memory location. In another embodiment of the invention, each of the first memory allocations is dynamically selected to store either entries each comprising a tag for referencing a memory location in the original memory area or entries each comprising both a tag for referencing a memory location in the original memory area and a corresponding data value associated with the memory location. Each of the plurality of entries stored in each of the second memory allocations may further comprise a tag for referencing a memory location in the original memory area. The accessing step may comprise reading entries in at least one of the second memory allocations. The accessing step may also comprise replacing entries in at least one of the second memory allocations. The step of unloading one of the second memory allocations may comprise writing changed entries from the second memory allocation back to associated memory locations in the original memory area. The step of unloading one of the second memory allocations may comprise writing changed entries from the second memory allocation back to associated entries in a corresponding first memory allocation. The step of loading one of the second memory allocations with data corresponding to entries stored in the subsequent one of the sequence of first memory allocations may comprise loading only data corresponding to entries having valid tags. The step of loading one of the second memory allocations with data corresponding to entries stored in the subsequent one of the sequence of first memory allocations may comprise loading only data corresponding to entries accessed in a previous frame. In one embodiment of the invention, caching data from an original memory area may further involve inserting an additional first memory allocation into the sequence of first memory allocations to accommodate additional accesses to memory locations in the original memory area. The sequence of first memory allocations may comprise a head list and a tail list, and wherein the inserting step comprises obtaining the additional first memory allocation from a free list and appending the additional first memory allocation to the head list. In one embodiment of the invention, caching data from an original memory area may further involve deleting one of the first memory allocations from the sequence of first memory allocations to accommodate deletion of memory accesses to memory locations in the original memory area. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an illustrative computer system containing memory components for which efficient data caching may be employed. FIG. 2 is a graphical illustration of a cache system containing a sequence of first memory allocations and a second sequence of memory allocations, in accordance with one embodiment of the present invention; FIG. 3 shows the sequence of first memory allocations and the sequence of second memory allocations previously shown in FIG. 2 , with the sequence of second memory allocations having shifted to hold data corresponding to a different range of the first memory allocations; FIG. 4 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 ; FIG. 5 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 1 ; FIG. 6 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 6 ; FIG. 7 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 7 ; FIG. 8 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 2 - 9 , and the replacement bucket corresponding to bucket 8 ; FIG. 9 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 ; FIG. 10 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 4 ; FIG. 11 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , the replacement bucket corresponding to bucket 4 , and occurrence of a first hit in bucket 7 ; and FIG. 12 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 4 . DETAILED DESCRIPTION OF THE INVENTION Basic Cache System Structure FIG. 2 is a graphical illustration of a cache system containing a sequence of first memory allocations 202 and a second sequence of memory allocations 204 , in accordance with one embodiment of the present invention. Together, the sequence of first memory allocations 202 and the sequence of second memory allocation 204 may be used to provide a cache system to cache data from an original memory area. The original memory area may refer to any portion of memory for which it may be appropriate to provide data caching. For instance, the original memory area may refer to parts of a frame buffer that holds data corresponding to pixels within a particular displayable image. In computer system 100 in FIG. 1 , for instance, such a frame buffer is accessed by graphics processing unit (GPU) 124 and may be implemented in graphics card local memory 126 , system memory 110 , or some other memory resource. Thus, the first memory allocations 202 and second memory allocations 204 may be used to provide a cache system for such a frame buffer. According to one embodiment of the invention, the second memory allocations 204 are implemented in a memory area that resides on the same semiconductor chip as the system requesting accesses to data, while the first memory allocations 202 are implemented in a memory area that does not reside on the same semiconductor chip. As such, in the context of computer system 100 , the second memory allocations 204 may be implemented in on-chip memory that is part of the semiconductor chip on which GPU 124 is implemented, while the first memory allocations 202 may be implemented in off-chip memory separate from GPU 124 , such as graphics card local memory 126 or system memory 110 . Referring back to FIG. 2 , the sequence of first memory allocations 202 hold enough tags to represent a history of data accesses that allows locality of access to be exploited. As shown in the figure, the sequence of first memory allocations 202 comprises memory allocations labeled 0 through 14 , and so on. Each one of the first memory allocations 202 is capable of storing a plurality of entries. Each such entry may comprise a tag that refers to a memory location in an original memory area. Each one of the first memory allocations 202 may be conceptually described as a “bucket” of entries. Thus, these buckets of entries may be used to hold tags that correspond to a history of data accesses to the original memory area. A sufficient number of the first memory allocations 202 , or buckets, are provided so that enough entries of tags may be stored to represent a history of data accesses that allows locality of access to be exploited. For example, for graphical data such as texel data, the locality of access may exist across frames. Thus, the first memory allocations 202 may collectively hold enough tags to represent data accesses corresponding to the rendering of an entire frame of graphical data. According to one embodiment of the invention, each entry stored in each of the first memory allocations 202 comprises a tag but not a corresponding data value. By not requiring a data value to be stored as part of each entry, the first memory allocations 202 may be implemented using a reduced amount of memory area. In an alternative embodiment, each entry stored in each of the first memory allocations 202 comprises not only a tag but also a corresponding data value. By requiring a data value to be stored as part of each entry, the first memory allocations 202 may be accessed directly to obtain corresponding data values. However, with this approach, the first memory allocations 202 may require a larger amount of memory area to implement. In yet another embodiment of the present invention, a hybrid technique allows each of the first memory allocations 202 to be dynamically selected between storing entries each comprising a tag or entries each comprising both a tag and a corresponding data value. In one example, in caching graphical data such as texel data, a larger pool of tag buckets and a smaller pool of texel data buckets may be available. Thus, for a particular bucket, storage of data as well as tags versus storage of tags only may be decided dynamically based on various considerations, such as efficiency of directly loading from texel memory, resultant miss rate, and compressibility. For example, both data and tags may be stored if data can be efficiently read from texel memory, without negatively impacting the miss rate, and if the data is highly compressible such that the writing out of both data and tag in compressed form may save read bandwidth on future passes. Referring back to FIG. 2 , the sequence of second memory allocations 204 hold data corresponding to a limited range of the first memory allocations 202 . In this manner, the sequence of second memory allocations 204 holds a “window” of cached data. As shown in the figure, the sequence of second memory allocations 204 currently holds data corresponding to tags stored in a limited range of first memory allocations, labeled 0 through 7 . Each one of the second memory allocations 204 is capable of storing a plurality of entries. Each such entry may comprise a data value that is associated with a memory location in an original memory area, such as main memory. As in the case of the first memory allocations 202 , each one of the second memory allocations 204 may be conceptually described as a “bucket” of entries. Entries in the second memory allocations 204 may thus be used to provide a window of cached data for data accesses to the original memory area. According to the present embodiment of the invention, the second memory allocations 204 are implemented in a memory area that resides on the same semiconductor chip as the system requesting accesses to data. For example, for a graphics processing unit that accesses graphical data for image rendering, the second memory allocations 204 may be implemented as on-chip memory that is part of the same semiconductor chip on which the graphics processing unit is implemented. FIG. 3 shows the sequence of first memory allocations 202 and the sequence of second memory allocations 204 previously shown in FIG. 2 , with the sequence of second memory allocations 204 having shifted to hold data corresponding to a different range of the first memory allocations 202 . As shown in the figure, the sequence of second memory allocations 204 now holds data corresponding to tags stored in a different range of first memory allocations, labeled 1 through 8 . As data access continues, the sequence of second memory allocations 204 may continue to be shifted in this manner to hold data corresponding to different ranges of first memory allocations, moving down the sequence of first memory allocations 202 . By storing only a window of data, the sequence of second memory allocations 204 may be implemented using a limited amount of memory space. Because the sequence of first memory allocations 202 contains sufficient tags to represent a history of previous data accesses to the original memory area, the data shifted into the sequence of second memory allocations 202 correspond to memory locations in the original memory area that are likely to be accessed. Thus, the arrangement of the sequence of first memory allocations 202 and sequence of second memory allocations 204 , as illustrated in the present embodiment of the invention, allow for greater hit rates to be achieved while utilizing a limited amount of costly memory area. In the context of a previous example, FIGS. 2 and 3 may illustrate a cache system associated with a graphics processing unit. The cache system may be used to cache texel data stored in main memory that the graphics processing unit accesses to render consecutive frames of graphical images. The cache system may include an off-chip cache (representing first memory allocations 202 ), organized as a sequence buckets. The cache system may also include an on-chip cache (representing second memory allocations 204 ), organized as a window of N buckets. As shown in FIGS. 2 and 3 , N=8. From one frame to the next, the sequence of texel data accesses may change very little. To exploit this inter-frame locality of access, the off-chip cache may store a full sequence of texel data accesses corresponding to an entire frame of image rendering. Each entry of this data may comprise a tag and a corresponding data value. Alternatively, each entry may comprise only a tag. These entries fill the sequence of buckets in the off-chip cache. By contrast, the on-chip cache only stores a window of N buckets of texel data accesses. Each entry in the on-chip cache may comprise both a tag and a corresponding data value. In this example, once the sequence of buckets in the off-chip cache have been initialized with data corresponding to an entire frame of image rendering, each new frame that follows may begin with the loading of the window of N buckets in the on-chip cache with data corresponding to the first N buckets in the off-chip cache. As rendering progresses, the window of N buckets in the on-chip cache may be shifted. Here, data may be unloaded from the oldest bucket of the on-chip cache. Then, data corresponding to the next bucket from the sequence of buckets in the off-chip cache may be loaded into the on-chip cache. The window of N buckets in the on-chip cache may thus be shifted to hold data corresponding to different ranges of the sequence of buckets in the off-chip cache. Examples of Detailed Cache Operations FIGS. 4 through 12 present a series of snapshots of the N buckets of on-chip cache associated with a cache system utilized by a graphics processing unit for rendering consecutive frame of texel data, corresponding to the example mentioned above in accordance with one embodiment of the invention. These snapshots illustrate in further detail cache operations that may be performed in connection with the N buckets of the on-chip cache. In each of these snapshots, “v” labels one of the N buckets of the on-chip cache as the replacement bucket. As the graphics processing unit accesses data for rendering texel data, a determination may be made as to whether each requested data access can be obtained from a cache entry in one of the N buckets. If so, the determination results in a “hit,” and the requested data is obtained from the cached entry. Otherwise, the determination results in a “miss,” and the requested data is obtained from the original memory area. The requested data obtained from the original memory area upon a “miss” is typically added as a new entry into the on-chip cache, replacing an old entry that is evicted as a result. The replacement bucket, as marked by “v” in FIGS. 4 through 12 , represents the selected bucket, amongst the N buckets, from which such an old entry is to be evicted and replaced. Also, in each of these snapshots, “*” represents recent activity, such as hits and replacements, that has taken place in particular ones of the N buckets. FIG. 4 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 . Here, each of the N buckets are initially empty. Thus, there are no hits and the buckets are filled with new entries as texel data is accessed for the first frame, beginning with bucket 0 . According to one embodiment of the invention, a replacement policy for choosing which of the N buckets to select as the replacement bucket, when there is a miss in all N buckets, may include the following rules: (1) start by designating the oldest bucket as the replacement bucket. Once misses start to cause eviction of entries that have been touched in the current frame, make the next bucket in the list the new replacement bucket, (2) advance the replacement bucket if a newer bucket is getting more hits currently, and (3) advance the replacement bucket if it is necessary as result of a window shift. Returning to FIG. 4 , bucket 0 is filled with new entries until an entry in bucket 0 that has been touched in the current frame becomes targeted to be evicted. At this point, the replacement bucket is advanced to bucket 1 , as illustrated in FIG. 5 . FIG. 5 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 1 . Bucket 1 is filled with new entries until an entry in bucket 1 that has been touched in the current frame becomes targeted to be evicted. At this point, the replacement bucket is advanced to bucket 2 . This process continues to fill subsequent buckets until eventually, the replacement bucket is advanced to bucket 6 , as illustrated in FIG. 6 . FIG. 6 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 6 . According to the present embodiment of the invention, the window may be shifted whenever there is a hit in the newest bucket (or a miss replacement into the newest bucket). Such a rule tends to cause the texture data to be loaded ahead of the access to such data for rendering, so that the rendering process does not stall waiting for a new bucket to be loaded. Returning to FIG. 6 , as bucket 6 is filled with new entries, the replacement bucket may be advanced to the last of the N buckets. At this point, the window of N buckets is advanced. First, data is unloaded from bucket 0 , which may involve writing the entries in bucket 0 that have been changed back to memory. A “dirty bit ram” may be employed that uses a bit to indicate whether each entry has been changed. The “dirty bit ram” may reside in the on-chip cache along with the texel data and tag data, as a binary value stored in each entry of each of the N buckets of the on-chip cache. Alternatively, it may reside as packed data in a distinct on-chip memory, stored separately from the entries of each of the N buckets of the on-chip cache. This alternative allows easy access to find the dirty entries. The write back to memory mentioned above may involve updating both the off-chip cache as well as the original memory area. For an entry in the off-chip cache that includes both a tag and a data value, both the tag and the data value may be updated using the changed entry. For an entry in the off-chip cache that includes only a tag, just the tag may be updated using the changed entry. Next, a new bucket 8 is loaded from the off-chip cache. Here, because the current frame is the first frame, bucket 8 initially remains empty. The window of N buckets after this advance is shown in FIG. 7 . FIG. 7 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 7 . As bucket 7 is filled with new entries, the replacement bucket may be advanced to the last of the N buckets. At this point, the window of N buckets is again advanced, in a similar fashion as described with respect to FIG. 6 . The window of N buckets after this advance is shown in FIG. 8 . FIG. 8 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 2 - 9 , and the replacement bucket corresponding to bucket 8 . The window of N buckets continues to be advanced in a similar fashion until the end of the frame. FIG. 9 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 . At the start of the next frame following the first frame, the window of N buckets in the on-chip cache is loaded with data corresponding to the first N buckets in the off-chip cache. For an entry in the off-chip cache that comprises both a tag and a data value, the data may be loaded directly from the off-chip cache. For an entry in the off-chip cache that comprises only a tag, the data may be loaded from a memory location in the original memory area referenced by the tag in the off-chip cache entry. According to one embodiment of the present invention, the on-chip cache is only loaded with those entries in the off-chip cache which are valid and were accessed in the previous frame. This may keep less useful data from being loaded and help to prevent failure conditions such as texture thrash cases. Once the window of N buckets in the on-chip cache has been loaded, it may be checked for requested data accesses, resulting in either a hit or a miss for each data access. Assuming that a high degree of inter-frame locality of access exits, the N buckets may produce mostly hits, along with a few misses. As the number of hits shifts to concentrate in a new bucket, the replacement bucket is shifted to the new bucket. FIG. 10 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 4 . As shown in FIG. 10 , the replacement bucket is shifted to bucket 4 , in response to the higher frequency of hits shown for bucket 4 . FIG. 11 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , the replacement bucket corresponding to bucket 4 , and occurrence of a first hit in bucket 7 . At some point, the last of the N buckets, shown here as bucket 7 , receives a hit. In response, the window of N buckets is advanced, in a similar fashion as described with respect to FIG. 6 . The window of N buckets after this advance is shown in FIG. 12 . FIG. 12 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 4 . Advanced Management of Memory Resources According to one embodiment of the invention, the sequence of first memory allocations 202 may be implemented as a linked list that is actively managed, by use of insertions and deletions. In the present embodiment of the invention, this is accomplished by maintaining three linked lists: a head list (memory allocations from an initial point of data access to the current point), a tail list (memory allocations that have not received any hits yet), and a free list (unused memory allocations available for insertion). In the example of a graphics processing unit rendering consecutive frames of texel data discussed previously, the head list may represent buckets in the off-chip cache from the beginning of the frame to the current point, and the tail list may represent buckets in the off-chip cache from the current point to the end of the frame. Such a mechanism may be implemented to handle the deletion or addition of a large number of texel data from one frame to the next. Continuing with the graphics processing unit example, when a replacement is to be performed in a bucket that has not gotten any hits yet, an insertion of a new bucket may instead be performed. This may involve breaking the tail list from the head list, shifting the buckets in the head list to make room for a new bucket (and shifting the on-chip cache accordingly), obtaining a new bucket from the free list into which the replacements may be performed, and adding the new bucket to the end of the head list. The first entry of the tail list may be maintained at the end of the on-chip window, until a hit occurs. Then, a hit in the tail list may be found and normal operation may resume. By allowing additional buckets to be inserted in this manner, the addition of a large number of texel data may be managed without writing over existing cache entries. Further, deletion of a large number of texel data may also be managed by detecting that the location in the cache record corresponding to the current point of data access has been lost—in other words, the correct beginning of the tail list has been lost. According to the present embodiment of the invention, this condition may be indicated by the occurrence of a large number of insertions. Upon detecting the loss of the beginning of the tail list, the cache system may enter a search mode to attempt to find the beginning of the tail list. In this search mode, one or more of the on-chip buckets may be converted to hold only tags, instead of tags along with data. By holding only tags, these on-chip buckets are capable of storing a much longer record of cache entries. In fact, many buckets worth of tags may be stored into a single on-chip cache, and these buckets can be quickly checked for hits. Once a bucket having a hit is detected in this manner, the bucket may be loaded to continue normal operation. Buckets between the end of the head list and the first bucket having a hit in the tail list may be deleted, by moving them to the free list. Also, if the free list is empty, entries from the tail list may be taken and used as free entries. This may be appropriate for the situation where accessed data changes significantly, and the cached bucket chain has to be rebuilt from scratch While the present invention has been described in terms of specific embodiments, it should be apparent to those skilled in the art that the scope of the present invention is not limited to the described specific embodiments. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that additions, subtractions, substitutions, and other modifications may be made without departing from the broader spirit and scope of the invention as set forth in the claims.
Methods, apparatuses, and systems are presented for caching. A cache memory area may be used for storing data from memory locations in an original memory area. The cache memory area may be used in conjunction with a repeatedly updated record of storage associated with the cache memory area. The repeatedly updated record of storage can thus provide a history of data storage associated with the cache memory area. The cache memory area may be loaded with entries previously stored in the cache memory area, by utilizing the repeatedly updated record of storage. In this manner, the record may be used to “warm up” the cache memory area, loading it with data entries that were previously cached and may be likely to be accessed again if repetition of memory accesses exists in the span of history captured by the repeatedly updated record of storage.
Identify and summarize the most critical features from the given passage.
[ "CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser.", "No. 12/618,772, filed Nov. 15, 2009, which is a continuation of U.S. patent application Ser.", "No. 11/424,659, filed Jun. 16, 2006, now U.S. Pat. No. 7,631,145, which claims the benefit of U.S. Provisional Patent Application No. 60/693,987, filed Jun. 23, 2005, which are incorporated by reference.", "BACKGROUND OF THE INVENTION Typical cache designs provide a dedicated area of memory to separately store a subset of a larger portion of data in memory.", "By storing data that is likely to be accessed again in the future in the dedicated area of memory, which may be more quickly or otherwise more efficiently accessed, overall efficiency of data access may be greatly improved.", "An underlying assumption of typical cache designs is locality of access, which refers to the likelihood that data accessed at one point in time is likely to be accessed again.", "If the subset of data stored in the dedicated memory area is likely to be accessed again in the future, the cache may be capable of achieving high levels of efficiency.", "On the other hand, if the subset of data stored in the dedicated memory area is not likely to be accessed again in the future, the cache is unlikely to achieve an acceptable measure of efficiency.", "In many computer systems, only a limited amount of dedicated memory area may be available for implementing a cache system.", "Depending on the nature of the data to be accessed, the limited amount of dedicated memory area may be insufficient to provide an efficient cache system following traditional cache designs.", "For example, one type of data that has potential for utilizing efficient caching is graphics data such as texel data to be accessed from memory by a graphics processing system and rendered on a display.", "From one frame to the next, there may be a high degree of locality of access.", "In other words, a high number of the memory locations accessed to retrieve texel data for the current frame rendered on the display may be accessed again to retrieve the same texel data for the next frame rendered on the display.", "This may often be the case, for instance, in situations where the rendered image remains largely unchanged from one frame to the next.", "Such locality of access from one frame to the next frame presents a potential for implementation of an efficient cache system.", "However, a prohibitively large amount of dedicated memory area may be required to exploit such locality of access, when traditional cache designs are utilized.", "In this example, the locality of access exists across frames.", "That is, a piece of texel data that is currently accessed is likely to be accessed again, but not until the next frame.", "Here, a traditional cache design that updates cache memory with the most recently accessed data may require enough dedicated memory area to provide caching for a full frame worth of texel data accesses, in order for the cache to perform properly.", "Otherwise, the cache may run out of memory space and begin overwriting useful cache entries stored from the current frame, before those cache entries are ever accessed in the next frame.", "Thus, cache entries that would have produced “hits”", "(a data access request that result in a match in the cache) in such a system may be destroyed prematurely, leading to an extremely low “hit rate”", "(ratio of data access requests that result in a match in the cache).", "FIG. 1 is a block diagram of an illustrative computer system 100 containing memory components for which efficient data caching may be employed.", "As shown, computer system 100 includes a graphics card 102 , a central processing unit (CPU) 104 , a chipset comprising a northbridge chip 106 and a southbridge chip 108 , system memory 110 , PCI slots 112 , disk drive controller 114 , universal serial bus (USB) connectors 116 , audio CODEC 118 , a super I/O controller 120 , and keyboard controller 122 .", "As shown in FIG. 1 , graphics card 102 includes a graphics processing unit (GPU) 124 and local memory 126 .", "Also, graphics card 102 is connected to a display 128 that may be part of computer system 100 .", "Here, GPU 124 is a semiconductor chip designed to perform graphics processing operations associated with rendering an image that may be presented on display 128 .", "Data residing in local memory 126 may be used as input data in the graphics rendering process, which produces a final image for presentation on display 128 .", "Alternatively or additionally, data residing in system memory 110 may also be used as input data in the graphics rendering process.", "These accesses to memory performed by GPU 124 may be associated with significant latencies that impact the performance of the system.", "It may thus be desirable to provide a data caching system so that GPU 124 may access such data in a more efficient manner.", "However, as discussed above, usage of the large amount of dedicated memory area required for caching data using traditional cache designs may simply be impracticable.", "For example, a typical graphics processing unit implemented as a semiconductor chip, such as GPU 124 , may have a limited amount of on-chip memory.", "This may be the case due to a variety of factors, such as manufacturing cost.", "The amount of dedicated memory area required to provide caching for a full frame worth of texel data accesses, for instance, may simply be too large to fit within the limited on-chip memory associated with the graphics processing unit.", "One alternative may be to forego the advantages of caching and design the system to accommodate deficiencies such as higher latencies associated with memory accesses without caching.", "Such a system is likely to incur high area costs associated with the accommodation of high access latency.", "Another alternative may be to simply implement a traditional cache design using the limited amount of memory area available, even though it may be insufficient to fully exploit the temporal locality of access of the underlying data.", "As previously mentioned, this likely leads to an inefficient cache characterized by an extremely low hit rate.", "Such a system is also likely to have inferior memory access performance.", "Thus, there is an urgent need for an improved cache design capable of utilizing a limited amount of memory area to achieve efficient data caching.", "BRIEF SUMMARY OF THE INVENTION The present invention relates to methods, apparatuses, and systems for caching data.", "A cache memory area may be used for storing data from memory locations in an original memory area.", "The cache memory area may be used in conjunction with a repeatedly updated record of storage associated with the cache memory area.", "The repeatedly updated record of storage can thus provide a history of data storage associated with the cache memory area.", "The cache memory area may be loaded with entries previously stored in the cache memory area, by utilizing the repeatedly updated record of storage.", "In this manner, the record may be used to “warm up”", "the cache memory area, loading it with data entries that were previously cached and may be likely to be accessed again if repetition of memory accesses exists in the span of history captured by the repeatedly updated record of storage.", "In one embodiment of the invention, the repeatedly updated record of storage comprises a sequence of first memory allocations, each of the first memory allocations capable of storing a plurality of entries each comprising a tag for referencing a memory location in the original memory area.", "Further, the cache memory area comprises a sequence of second memory corresponding to a limited range of the sequence of first memory locations, each of the second memory allocations capable of storing a plurality of entries each comprising a data value associated with a memory location in the original memory area.", "In this embodiment, accesses occur to at least one of the second memory allocations, and the limited range to which the second sequence of memory allocations correspond is advanced by unloading data from one of the second memory allocations and loading one of the second memory allocations with data corresponding to entries stored in a subsequent one of the sequence of first memory allocations.", "The sequence of second memory allocations may be implemented as on-chip memory within a semiconductor chip containing a system requesting access to a memory location in the original memory area, wherein the sequence of first memory allocations is implemented as off-chip memory that is not part of the semiconductor chip containing the system requesting access to the memory location in the original memory area.", "The system requesting access may be a graphics processing unit requesting access to texel data stored in the original memory area.", "In one embodiment of the invention, each of the plurality of entries stored in each of the first memory allocations comprises both a tag for referencing a memory location in the original memory area and a corresponding data value associated with the memory location.", "In another embodiment of the invention, each of the first memory allocations is dynamically selected to store either entries each comprising a tag for referencing a memory location in the original memory area or entries each comprising both a tag for referencing a memory location in the original memory area and a corresponding data value associated with the memory location.", "Each of the plurality of entries stored in each of the second memory allocations may further comprise a tag for referencing a memory location in the original memory area.", "The accessing step may comprise reading entries in at least one of the second memory allocations.", "The accessing step may also comprise replacing entries in at least one of the second memory allocations.", "The step of unloading one of the second memory allocations may comprise writing changed entries from the second memory allocation back to associated memory locations in the original memory area.", "The step of unloading one of the second memory allocations may comprise writing changed entries from the second memory allocation back to associated entries in a corresponding first memory allocation.", "The step of loading one of the second memory allocations with data corresponding to entries stored in the subsequent one of the sequence of first memory allocations may comprise loading only data corresponding to entries having valid tags.", "The step of loading one of the second memory allocations with data corresponding to entries stored in the subsequent one of the sequence of first memory allocations may comprise loading only data corresponding to entries accessed in a previous frame.", "In one embodiment of the invention, caching data from an original memory area may further involve inserting an additional first memory allocation into the sequence of first memory allocations to accommodate additional accesses to memory locations in the original memory area.", "The sequence of first memory allocations may comprise a head list and a tail list, and wherein the inserting step comprises obtaining the additional first memory allocation from a free list and appending the additional first memory allocation to the head list.", "In one embodiment of the invention, caching data from an original memory area may further involve deleting one of the first memory allocations from the sequence of first memory allocations to accommodate deletion of memory accesses to memory locations in the original memory area.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an illustrative computer system containing memory components for which efficient data caching may be employed.", "FIG. 2 is a graphical illustration of a cache system containing a sequence of first memory allocations and a second sequence of memory allocations, in accordance with one embodiment of the present invention;", "FIG. 3 shows the sequence of first memory allocations and the sequence of second memory allocations previously shown in FIG. 2 , with the sequence of second memory allocations having shifted to hold data corresponding to a different range of the first memory allocations;", "FIG. 4 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 ;", "FIG. 5 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 1 ;", "FIG. 6 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 6 ;", "FIG. 7 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 7 ;", "FIG. 8 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 2 - 9 , and the replacement bucket corresponding to bucket 8 ;", "FIG. 9 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 ;", "FIG. 10 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 4 ;", "FIG. 11 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , the replacement bucket corresponding to bucket 4 , and occurrence of a first hit in bucket 7 ;", "and FIG. 12 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 4 .", "DETAILED DESCRIPTION OF THE INVENTION Basic Cache System Structure FIG. 2 is a graphical illustration of a cache system containing a sequence of first memory allocations 202 and a second sequence of memory allocations 204 , in accordance with one embodiment of the present invention.", "Together, the sequence of first memory allocations 202 and the sequence of second memory allocation 204 may be used to provide a cache system to cache data from an original memory area.", "The original memory area may refer to any portion of memory for which it may be appropriate to provide data caching.", "For instance, the original memory area may refer to parts of a frame buffer that holds data corresponding to pixels within a particular displayable image.", "In computer system 100 in FIG. 1 , for instance, such a frame buffer is accessed by graphics processing unit (GPU) 124 and may be implemented in graphics card local memory 126 , system memory 110 , or some other memory resource.", "Thus, the first memory allocations 202 and second memory allocations 204 may be used to provide a cache system for such a frame buffer.", "According to one embodiment of the invention, the second memory allocations 204 are implemented in a memory area that resides on the same semiconductor chip as the system requesting accesses to data, while the first memory allocations 202 are implemented in a memory area that does not reside on the same semiconductor chip.", "As such, in the context of computer system 100 , the second memory allocations 204 may be implemented in on-chip memory that is part of the semiconductor chip on which GPU 124 is implemented, while the first memory allocations 202 may be implemented in off-chip memory separate from GPU 124 , such as graphics card local memory 126 or system memory 110 .", "Referring back to FIG. 2 , the sequence of first memory allocations 202 hold enough tags to represent a history of data accesses that allows locality of access to be exploited.", "As shown in the figure, the sequence of first memory allocations 202 comprises memory allocations labeled 0 through 14 , and so on.", "Each one of the first memory allocations 202 is capable of storing a plurality of entries.", "Each such entry may comprise a tag that refers to a memory location in an original memory area.", "Each one of the first memory allocations 202 may be conceptually described as a “bucket”", "of entries.", "Thus, these buckets of entries may be used to hold tags that correspond to a history of data accesses to the original memory area.", "A sufficient number of the first memory allocations 202 , or buckets, are provided so that enough entries of tags may be stored to represent a history of data accesses that allows locality of access to be exploited.", "For example, for graphical data such as texel data, the locality of access may exist across frames.", "Thus, the first memory allocations 202 may collectively hold enough tags to represent data accesses corresponding to the rendering of an entire frame of graphical data.", "According to one embodiment of the invention, each entry stored in each of the first memory allocations 202 comprises a tag but not a corresponding data value.", "By not requiring a data value to be stored as part of each entry, the first memory allocations 202 may be implemented using a reduced amount of memory area.", "In an alternative embodiment, each entry stored in each of the first memory allocations 202 comprises not only a tag but also a corresponding data value.", "By requiring a data value to be stored as part of each entry, the first memory allocations 202 may be accessed directly to obtain corresponding data values.", "However, with this approach, the first memory allocations 202 may require a larger amount of memory area to implement.", "In yet another embodiment of the present invention, a hybrid technique allows each of the first memory allocations 202 to be dynamically selected between storing entries each comprising a tag or entries each comprising both a tag and a corresponding data value.", "In one example, in caching graphical data such as texel data, a larger pool of tag buckets and a smaller pool of texel data buckets may be available.", "Thus, for a particular bucket, storage of data as well as tags versus storage of tags only may be decided dynamically based on various considerations, such as efficiency of directly loading from texel memory, resultant miss rate, and compressibility.", "For example, both data and tags may be stored if data can be efficiently read from texel memory, without negatively impacting the miss rate, and if the data is highly compressible such that the writing out of both data and tag in compressed form may save read bandwidth on future passes.", "Referring back to FIG. 2 , the sequence of second memory allocations 204 hold data corresponding to a limited range of the first memory allocations 202 .", "In this manner, the sequence of second memory allocations 204 holds a “window”", "of cached data.", "As shown in the figure, the sequence of second memory allocations 204 currently holds data corresponding to tags stored in a limited range of first memory allocations, labeled 0 through 7 .", "Each one of the second memory allocations 204 is capable of storing a plurality of entries.", "Each such entry may comprise a data value that is associated with a memory location in an original memory area, such as main memory.", "As in the case of the first memory allocations 202 , each one of the second memory allocations 204 may be conceptually described as a “bucket”", "of entries.", "Entries in the second memory allocations 204 may thus be used to provide a window of cached data for data accesses to the original memory area.", "According to the present embodiment of the invention, the second memory allocations 204 are implemented in a memory area that resides on the same semiconductor chip as the system requesting accesses to data.", "For example, for a graphics processing unit that accesses graphical data for image rendering, the second memory allocations 204 may be implemented as on-chip memory that is part of the same semiconductor chip on which the graphics processing unit is implemented.", "FIG. 3 shows the sequence of first memory allocations 202 and the sequence of second memory allocations 204 previously shown in FIG. 2 , with the sequence of second memory allocations 204 having shifted to hold data corresponding to a different range of the first memory allocations 202 .", "As shown in the figure, the sequence of second memory allocations 204 now holds data corresponding to tags stored in a different range of first memory allocations, labeled 1 through 8 .", "As data access continues, the sequence of second memory allocations 204 may continue to be shifted in this manner to hold data corresponding to different ranges of first memory allocations, moving down the sequence of first memory allocations 202 .", "By storing only a window of data, the sequence of second memory allocations 204 may be implemented using a limited amount of memory space.", "Because the sequence of first memory allocations 202 contains sufficient tags to represent a history of previous data accesses to the original memory area, the data shifted into the sequence of second memory allocations 202 correspond to memory locations in the original memory area that are likely to be accessed.", "Thus, the arrangement of the sequence of first memory allocations 202 and sequence of second memory allocations 204 , as illustrated in the present embodiment of the invention, allow for greater hit rates to be achieved while utilizing a limited amount of costly memory area.", "In the context of a previous example, FIGS. 2 and 3 may illustrate a cache system associated with a graphics processing unit.", "The cache system may be used to cache texel data stored in main memory that the graphics processing unit accesses to render consecutive frames of graphical images.", "The cache system may include an off-chip cache (representing first memory allocations 202 ), organized as a sequence buckets.", "The cache system may also include an on-chip cache (representing second memory allocations 204 ), organized as a window of N buckets.", "As shown in FIGS. 2 and 3 , N=8.", "From one frame to the next, the sequence of texel data accesses may change very little.", "To exploit this inter-frame locality of access, the off-chip cache may store a full sequence of texel data accesses corresponding to an entire frame of image rendering.", "Each entry of this data may comprise a tag and a corresponding data value.", "Alternatively, each entry may comprise only a tag.", "These entries fill the sequence of buckets in the off-chip cache.", "By contrast, the on-chip cache only stores a window of N buckets of texel data accesses.", "Each entry in the on-chip cache may comprise both a tag and a corresponding data value.", "In this example, once the sequence of buckets in the off-chip cache have been initialized with data corresponding to an entire frame of image rendering, each new frame that follows may begin with the loading of the window of N buckets in the on-chip cache with data corresponding to the first N buckets in the off-chip cache.", "As rendering progresses, the window of N buckets in the on-chip cache may be shifted.", "Here, data may be unloaded from the oldest bucket of the on-chip cache.", "Then, data corresponding to the next bucket from the sequence of buckets in the off-chip cache may be loaded into the on-chip cache.", "The window of N buckets in the on-chip cache may thus be shifted to hold data corresponding to different ranges of the sequence of buckets in the off-chip cache.", "Examples of Detailed Cache Operations FIGS. 4 through 12 present a series of snapshots of the N buckets of on-chip cache associated with a cache system utilized by a graphics processing unit for rendering consecutive frame of texel data, corresponding to the example mentioned above in accordance with one embodiment of the invention.", "These snapshots illustrate in further detail cache operations that may be performed in connection with the N buckets of the on-chip cache.", "In each of these snapshots, “v”", "labels one of the N buckets of the on-chip cache as the replacement bucket.", "As the graphics processing unit accesses data for rendering texel data, a determination may be made as to whether each requested data access can be obtained from a cache entry in one of the N buckets.", "If so, the determination results in a “hit,” and the requested data is obtained from the cached entry.", "Otherwise, the determination results in a “miss,” and the requested data is obtained from the original memory area.", "The requested data obtained from the original memory area upon a “miss”", "is typically added as a new entry into the on-chip cache, replacing an old entry that is evicted as a result.", "The replacement bucket, as marked by “v”", "in FIGS. 4 through 12 , represents the selected bucket, amongst the N buckets, from which such an old entry is to be evicted and replaced.", "Also, in each of these snapshots, “*”", "represents recent activity, such as hits and replacements, that has taken place in particular ones of the N buckets.", "FIG. 4 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 .", "Here, each of the N buckets are initially empty.", "Thus, there are no hits and the buckets are filled with new entries as texel data is accessed for the first frame, beginning with bucket 0 .", "According to one embodiment of the invention, a replacement policy for choosing which of the N buckets to select as the replacement bucket, when there is a miss in all N buckets, may include the following rules: (1) start by designating the oldest bucket as the replacement bucket.", "Once misses start to cause eviction of entries that have been touched in the current frame, make the next bucket in the list the new replacement bucket, (2) advance the replacement bucket if a newer bucket is getting more hits currently, and (3) advance the replacement bucket if it is necessary as result of a window shift.", "Returning to FIG. 4 , bucket 0 is filled with new entries until an entry in bucket 0 that has been touched in the current frame becomes targeted to be evicted.", "At this point, the replacement bucket is advanced to bucket 1 , as illustrated in FIG. 5 .", "FIG. 5 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 1 .", "Bucket 1 is filled with new entries until an entry in bucket 1 that has been touched in the current frame becomes targeted to be evicted.", "At this point, the replacement bucket is advanced to bucket 2 .", "This process continues to fill subsequent buckets until eventually, the replacement bucket is advanced to bucket 6 , as illustrated in FIG. 6 .", "FIG. 6 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 6 .", "According to the present embodiment of the invention, the window may be shifted whenever there is a hit in the newest bucket (or a miss replacement into the newest bucket).", "Such a rule tends to cause the texture data to be loaded ahead of the access to such data for rendering, so that the rendering process does not stall waiting for a new bucket to be loaded.", "Returning to FIG. 6 , as bucket 6 is filled with new entries, the replacement bucket may be advanced to the last of the N buckets.", "At this point, the window of N buckets is advanced.", "First, data is unloaded from bucket 0 , which may involve writing the entries in bucket 0 that have been changed back to memory.", "A “dirty bit ram”", "may be employed that uses a bit to indicate whether each entry has been changed.", "The “dirty bit ram”", "may reside in the on-chip cache along with the texel data and tag data, as a binary value stored in each entry of each of the N buckets of the on-chip cache.", "Alternatively, it may reside as packed data in a distinct on-chip memory, stored separately from the entries of each of the N buckets of the on-chip cache.", "This alternative allows easy access to find the dirty entries.", "The write back to memory mentioned above may involve updating both the off-chip cache as well as the original memory area.", "For an entry in the off-chip cache that includes both a tag and a data value, both the tag and the data value may be updated using the changed entry.", "For an entry in the off-chip cache that includes only a tag, just the tag may be updated using the changed entry.", "Next, a new bucket 8 is loaded from the off-chip cache.", "Here, because the current frame is the first frame, bucket 8 initially remains empty.", "The window of N buckets after this advance is shown in FIG. 7 .", "FIG. 7 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 7 .", "As bucket 7 is filled with new entries, the replacement bucket may be advanced to the last of the N buckets.", "At this point, the window of N buckets is again advanced, in a similar fashion as described with respect to FIG. 6 .", "The window of N buckets after this advance is shown in FIG. 8 .", "FIG. 8 is a snapshot of the window of N buckets in the on-chip cache, as a first frame of texel data is initially rendered, with the window corresponding to buckets 2 - 9 , and the replacement bucket corresponding to bucket 8 .", "The window of N buckets continues to be advanced in a similar fashion until the end of the frame.", "FIG. 9 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 0 .", "At the start of the next frame following the first frame, the window of N buckets in the on-chip cache is loaded with data corresponding to the first N buckets in the off-chip cache.", "For an entry in the off-chip cache that comprises both a tag and a data value, the data may be loaded directly from the off-chip cache.", "For an entry in the off-chip cache that comprises only a tag, the data may be loaded from a memory location in the original memory area referenced by the tag in the off-chip cache entry.", "According to one embodiment of the present invention, the on-chip cache is only loaded with those entries in the off-chip cache which are valid and were accessed in the previous frame.", "This may keep less useful data from being loaded and help to prevent failure conditions such as texture thrash cases.", "Once the window of N buckets in the on-chip cache has been loaded, it may be checked for requested data accesses, resulting in either a hit or a miss for each data access.", "Assuming that a high degree of inter-frame locality of access exits, the N buckets may produce mostly hits, along with a few misses.", "As the number of hits shifts to concentrate in a new bucket, the replacement bucket is shifted to the new bucket.", "FIG. 10 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , and the replacement bucket corresponding to bucket 4 .", "As shown in FIG. 10 , the replacement bucket is shifted to bucket 4 , in response to the higher frequency of hits shown for bucket 4 .", "FIG. 11 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 0 - 7 , the replacement bucket corresponding to bucket 4 , and occurrence of a first hit in bucket 7 .", "At some point, the last of the N buckets, shown here as bucket 7 , receives a hit.", "In response, the window of N buckets is advanced, in a similar fashion as described with respect to FIG. 6 .", "The window of N buckets after this advance is shown in FIG. 12 .", "FIG. 12 is a snapshot of the window of N buckets in the on-chip cache, as the next frame of texel data is initially rendered, with the window corresponding to buckets 1 - 8 , and the replacement bucket corresponding to bucket 4 .", "Advanced Management of Memory Resources According to one embodiment of the invention, the sequence of first memory allocations 202 may be implemented as a linked list that is actively managed, by use of insertions and deletions.", "In the present embodiment of the invention, this is accomplished by maintaining three linked lists: a head list (memory allocations from an initial point of data access to the current point), a tail list (memory allocations that have not received any hits yet), and a free list (unused memory allocations available for insertion).", "In the example of a graphics processing unit rendering consecutive frames of texel data discussed previously, the head list may represent buckets in the off-chip cache from the beginning of the frame to the current point, and the tail list may represent buckets in the off-chip cache from the current point to the end of the frame.", "Such a mechanism may be implemented to handle the deletion or addition of a large number of texel data from one frame to the next.", "Continuing with the graphics processing unit example, when a replacement is to be performed in a bucket that has not gotten any hits yet, an insertion of a new bucket may instead be performed.", "This may involve breaking the tail list from the head list, shifting the buckets in the head list to make room for a new bucket (and shifting the on-chip cache accordingly), obtaining a new bucket from the free list into which the replacements may be performed, and adding the new bucket to the end of the head list.", "The first entry of the tail list may be maintained at the end of the on-chip window, until a hit occurs.", "Then, a hit in the tail list may be found and normal operation may resume.", "By allowing additional buckets to be inserted in this manner, the addition of a large number of texel data may be managed without writing over existing cache entries.", "Further, deletion of a large number of texel data may also be managed by detecting that the location in the cache record corresponding to the current point of data access has been lost—in other words, the correct beginning of the tail list has been lost.", "According to the present embodiment of the invention, this condition may be indicated by the occurrence of a large number of insertions.", "Upon detecting the loss of the beginning of the tail list, the cache system may enter a search mode to attempt to find the beginning of the tail list.", "In this search mode, one or more of the on-chip buckets may be converted to hold only tags, instead of tags along with data.", "By holding only tags, these on-chip buckets are capable of storing a much longer record of cache entries.", "In fact, many buckets worth of tags may be stored into a single on-chip cache, and these buckets can be quickly checked for hits.", "Once a bucket having a hit is detected in this manner, the bucket may be loaded to continue normal operation.", "Buckets between the end of the head list and the first bucket having a hit in the tail list may be deleted, by moving them to the free list.", "Also, if the free list is empty, entries from the tail list may be taken and used as free entries.", "This may be appropriate for the situation where accessed data changes significantly, and the cached bucket chain has to be rebuilt from scratch While the present invention has been described in terms of specific embodiments, it should be apparent to those skilled in the art that the scope of the present invention is not limited to the described specific embodiments.", "The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.", "It will, however, be evident that additions, subtractions, substitutions, and other modifications may be made without departing from the broader spirit and scope of the invention as set forth in the claims." ]
BACKGROUND OF THE INVENTION The present invention relates to CM-chitin derivatives having a tripeptide, Arg-Gly-Asp (SEQ ID NO: 1), as an essential unit, and salts thereof, as well as a composition for inhibiting adhesion of animal cells and a composition for inhibiting coagulation of blood platelets. Fibronectin is a protein involved in the cell-extracellular substrate adhesion and is likewise thought to be involved in coagulation of blood platelets and the metastasis of cancer. These interactions are mediated by a series of receptors present in the cell surface region. It is confirmed that these receptors can specifically recognize an amino acid sequence: Arg-Gly-Asp (SEQ ID NO: 1) of the fibronectin although the fibronectin is a macromolecule having a molecular weight of about 250,000 and it has been reported that the sequence plays an important role in the interaction between the receptors and the fibronectin (Nature, 1984, 309, p. 30). Since then, there have been many studies conducted in which an oligopeptide or polypeptide having such an amino acid sequence: Arg-Gly-Asp (SEQ ID NO: 1) is used. There have been various studies reported, such as a method for inhibiting the coagulation of blood platelets by the use of various linear and cyclic oligopeptides having an Arg-Gly-Asp (SEQ ID NO: 1) sequence (Polymer Preprints, Japan, 1989, 38, p. 3149; Japanese Unexamined Patent Publication (hereinafter referred to as "J. P. KOKAI") No. Hei 2-174797); a method in which a peptide having an Arg-Gly-Asp (SEQ ID NO: 1) sequence is used as a cell movement-inhibiting agent (J. P. KOKAI No. Hei 2-4716); and a method using as a cell-adhesive membrane, a PMMA film on which Arg-Gly-Asp (SEQ ID NO: 1) sequences are immobilized (Polymer Preprints, Japan, 1988, 37, p. 705). In addition, J. P. KOKAI Nos. Hei 1-309682 and Hei 1-305960 disclose a method which comprises peptides having Arg-Gly-Asp (SEQ ID NO: 1) sequences as essential structural units covalently bonded to a polymer and the resulting product is used as a substrate for cultivating animal cells or for biological composite artificial organs and J. P. KOKAI No. Sho 64-6217 discloses a method in which a polypeptide having Arg-Gly-Asp-Ser (SEQ ID NO: 7) sequences is used as a platelet protective agent for blood taken out of the body. Further, there is a known method comprising inhibiting the metastasis of cancer by the use of an oligopeptide having Arg-Gly-Asp (SEQ ID NO: 1) sequences or a polypeptide having the sequence as repeating units (Int. J. Biol. Macromol., 1989, 11, p. 23; ibid, 1989, 11, p. 226; Jpn. J. Cancer Res., 1989, 60, p. 722). Chitin is a polysaccharide in which N-acetyl-D-glucosamine is linked through the β- (1→4) bond and is a main component of the exoskeleton of Crustacea and Insects. It is widely distributed in lower animals and invertebrates and serves to support and/or protect the organs. The functions thereof correspond to those of cellulose in the plant. Chitin is also called the last biomass, derivatives thereof have been variously studied recently and, in particular, many studies concerning solvent-soluble chitin derivatives have been reported. Among them, CM-chitin in which a carboxymethyl group is bonded to the C-6 hydroxyl group is water-soluble and a very important compound as a starting material for preparing various chitin derivatives. Chitin and derivatives thereof are detailed in "Applications of Chitin Chitosan", edited by the Society for research of chitin chitosan published by Gihodo Publishing Company and "The Last Biomass: Chitin Chitosan", edited by the same Society, published by Gihodo Publishing Company. The CM-chitin causes deacetylation during carboxylation and this indicates the presence of an amino group in addition to a carboxyl group. The amino group thereof can easily undergo carboxylation with a dibasic acid or a derivative thereof, preferably a polybasic acid anhydride. The N, O-sulfation of the CM-chitin is also easy. However, there is no known compound in which an oligopeptide having an Arg-Gly-Asp (SEQ ID NO: 1) sequence as an essential unit or a polypeptide having the sequences as repeating unit. If such an oligopeptide or a polypeptide is introduced into a compound, it would be expected that the ability of bonding thereof to a receptor and the stability thereof in blood would be greatly enhanced. Accordingly, an object of the present invention is to provide a novel CM-chitin derivative. Another object of the present invention is to provide a composition for inhibiting adhesion of animal cells containing the chitin derivative as an effective component. A further object of the present invention is to provide a composition for suppressing coagulation of blood platelets which comprises the novel CM-chitin derivative as an effective component. According to an aspect of the present invention, a CM-chitin derivative is provided having, as an essential structural unit, an adhesive peptide represented by the following general formula (I) through any one of an amido bond, an ester bond, an ether bond and a urethane bond on the side chain and salts thereof: -[R.sup.1 ]-[CO]-([X]-Arg-Gly-Asp-[Y]).sub.n -[Z]-[R.sup.2 ]--. . . (I) (SEQ ID NO: 1) In general formula (I), [ ] means that each corresponding group or residue may be present or absent and if they are present, X and Y each represents an amino acid residue selected from the group consisting of Ser, Gly, Val, Asn and Pro or a peptide residue consisting of two or more of the amino acids; Z represents --O-- or --NH--; one of R 1 and R 2 represents a hydrogen atom, a linear or branched alkyl group having 1 to 9 carbon atoms or an aryl group having 6 to 9 carbon atoms in which the alkyl and aryl groups may be substituted and the other represents a hydrogen atom, a linear or branched alkylene group having 1 to 9 carbon atoms or an arylene group having 6 to 9 carbon atoms wherein the alkylene and arylene groups may be substituted; and n is an integer ranging from 1 to 5. Examples of substituents for R 1 and R 2 include halogen atoms, carbonyl, carboxyl, amino, hydroxyl, sulfo, aryl, nitro and cyano groups, unsaturated hydrocarbon group which has a double bond and triple bond and they may have two or more substituents. According to another aspect of the present invention, there is provided a composition for inhibiting adhesion of animal cells or for suppressing coagulation of blood platelets comprising the foregoing CM-chitin derivative as an effective component. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a CM-chitin derivative in which an adhesive peptide having, as an essential unit, an Arg-Gly-Asp (SEQ ID No: 1) sequence is covalently bonded to a sulfated CM-chitin, carboxylated CM-chitin or CM-chitin. The molecular weight of the CM-chitin derivatives is not more than 200,000, in particular, 3,000 to 100,000 and the derivative is preferably soluble in water at room temperature. Examples of carboxylating agents used herein are succinic anhydride, maleic anhydride, phthalic anhydride, itaconic anhydride, citraconic anhydride, pyromellitic anhydride and trimellitic anhydride. Amino acids used in the adhesive peptide may be either L- or D-isomers and preferably L-isomers. Examples of the salts of the CM-chitin derivatives of the invention are those with inorganic acids such as hydrochlorides, sulfates, nitrates, phosphates and borates; and those with organic acid s such as acetates, trifluoroacetates, trifluoromethanesulfonates, lactates and tartrates. Methods for synthesizing these peptides are not restricted to specific ones and may be liquid phase and solid phase methods and those in which an automatic synthesizer is employed. These synthesis methods are detailed in, for instance, Lectures on Biochemical Experiments, "Chemistry of Proteins IV", pp. 207-495, edited by Biochemical Society of Japan, published by Tokyo Kagaku Dojin Publishing Company; Lectures on Biochemical Experiments, Second Series, "Chemistry of Proteins (the last volume)", edited by Biochemical Society of Japan, published by Tokyo Kagaku Dojin Publishing Company; and "Fundamental Knowledge and Experiments of Peptide Synthesis", edited by Izumiya et al., published by Maruzen Publishing Company. Alternatively, it is also possible to use commercially available synthetic peptides. Amide bond-forming methods in which agents such as cyanogen bromide, acid azides or water-soluble carbodiimides can be used for coupling the CM-chitin or carboxylated CM-chitin with an adhesive peptide. The CM-chitin derivatives of the invention have a core sequence: Arg-Gly-Asp (SEQ ID No: 1) of a cell-cohesive protein and are adhered to cells through the core sequence according to a mechanism similar to that for the cell-adhesive protein. For this reason, they serve as agonists or antagonists of the cell-adhesive protein which exhibit a variety of biological activities such as immunoregulating action, wound-healing action, action for inhibiting platelet coagulation observed in blood vessels and nervous disorder-healing action. Thus, at least one of the CM-chitin derivatives of the invention can be administered to patients together with commonly used optional carriers or pharmaceutical auxiliary agents in the form of wound-healing agents, immunoregulating agents or platelet coagulation-inhibiting agents. In particular, the derivatives are preferably used as animal cell adhesion-inhibiting agents or platelet coagulation-inhibiting agents. The dose thereof varies depending on various factors such as conditions to be treated, age and weight of patients and generally ranges from 0.2 μg/kg to 400 mg/kg. The CM-chitin derivatives may be administered through various routes which are generally used for the administration of peptide-containing medicines. For instance, they are preferably administered parenterally, intravenously, intramuscularly and subcutaneously. In the preparation of injectable pharmaceutical preparations containing the same, the chitin derivative is dissolved in, for instance, PBS or physiological saline to give an injectable solution. These pharmaceutical preparations may comprise a commonly used stabilizer such as glycine and albumin. Moreover, the chitin derivative may be parenterally administered by encapsulating them in liposomes to give microcapsules. Further, if they are formulated in the form of, for instance, suppository, sublingual tablets and nasal sprays, they can be absorbed through mucous other than digestive tracts. The present invention will hereinafter be explained in more detail with reference to the following non-limitative working Examples and Preparation Examples, but the present invention is by no means limited to these specific Examples. Preparation Example 1: Synthesis of Cohesive Peptide by Solid Phase Method Synthesis of this peptide was performed using a peptide synthesizer according to the Merrifield System. α- Amino groups were protected with Boc, the resulting peptide was purified by preparative high performance liquid chromatography (HPLC) after separating from the solid phase of a resin to give an adhesive synthetic peptide showing a single peak. ______________________________________Adhesive Peptides SynthesizedName Structural Formula Sequence No. Yield______________________________________Pep- H--(Arg--Gly--Asp)--OH (SEQ ID NO: 1) 37%tide-1Pep- H--(Arg--Gly--Asp).sub.2 --OH (SEQ ID NO: 2) 28%tide-2Pep- H--(Arg--Gly--Asp).sub.3 --OH (SEQ ID NO: 3) 19%tide-3Pep- H--(Arg--Gly--Asp).sub.5 --OH (SEQ ID NO: 4) 11%tide-4______________________________________ Preparation Example 2: Syntheses of Peptide-5: H-(Arg-Gly-Asp-Ser-Gly)-NH 2 (SEQ ID NO: 5) The peptide-5 was prepared by a liquid phase method according to a sequential-extension method. (1) Synthesis of Boc Ser(Bzl)GlyNH 2 To 400 ml of CH 2 Cl 2 , there was dissolved 59 g (0.2 mole) of Boc Ser(Bzl) and then 41.2 g (0.2 mole) of DCC was added thereto with ice-cooling. A solution of 22.1 g of GlyNH 2 . HC1 in 400 ml of CH 2 C1 2 which was then neutralized by the addition of 20.2 g of N-methylmorpholine under ice-cooling was added to the resulting solution. The mixture was stirred for 3 hours under ice-cooling and then at room temperature overnight. After separating precipitates formed by filtration, the filtrate was concentrated under reduced pressure and then the residue obtained was dissolved in ethyl acetate. The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 58.3 g (yield 83%) of a product as white powder. (2) Synthesis of BocAsp(OBzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 1) There was added 400 ml of TFA/CH 2 C1 2 (=1/1) to 56.2 g (0.16 mole) of BocSer((Bzl)GlyNH 2 , the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl. After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure. There were dissolved the resulting compound and 51 7 g (0.16 mole) of BocAsp (Obzl) in 800 ml of CH 2 Cl 2 followed by addition of 33 g (0.16 mole) of DCC under ice-cooling, stirring for 3 hours and further at room temperature overnight. After distilling off the CH 2 Cl 2 under reduced pressure, the resulting residue was dissolved in ethyl acetate. The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 71.2 g (yield 80%) of a product as white powder. (3) Synthesis of BocGlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 9) There was added 400 ml of TFA/CH 2 Cl 2 (=1/1) to 66.7 g (0.12 mole) of BocAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 1), the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl. After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure. There were dissolved the resulting compound and 51.7 g (0.12 mole) of BocGly in 700 ml of CH 2 Cl 2 followed by addition of 24.7 g (0.12 mo)e) of DCC under ice-cooling, stirring for 3 hours and further at room temperature overnight. After removing the resulting DCurea by filtration and distilling off the CH 2 Cl 2 under reduced pressure, the resulting residue was dissolved in ethyl acetate. The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 61.8 g (yield 84%) of a product as white powder. Synthesis of BocArg(Mts)GlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 5) There was added 400 ml of TFA/CH 2 Cl 2 (=1/1) to 61.3 g (0.1 mole) of BocGlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 9), the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl. After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure. There was dissolved the resulting compound and 45.6 g (0.1 mole) of BocArg(Mts) (Mts: a mesitylene-2-sulfonyl group) in 800 ml of DMF followed by addition of 22.5 g (0.1 mole) of DCC and 14 g (0.1 mole) of HOBt under ice-cooling, stirring for 3 hours and further at room temperature overnight. After removing the resulting Dcurea by filtration and distilling off the solvent under reduced pressure, the resulting residue was dissolved in ethyl acetate. The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 42.8 g (yield 45%) of a product as white powder. (5) Removal of Protective Groups (Synthesis of Peptide-5) To a solution of BocArg(Mts)GlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO:5) (5 g; 5.3 Mm) in TFA, there was added, under ice-cooling, a 1M solution of trifluoromethanesulfonic acid-thioanisole-m-cresol in TFA to react these for one hour and then the protective groups present on the side chains and termini of the peptide were removed. The reaction solution was poured into ether, the resulting oily precipitates were dissolved in distilled water, then washed with ethyl acetate, passed through a column packed with an anion-exchange resin (Amberlite IRA-400Cl Type) to thus convert into hydrochloride and lyophilized to give 2.17 g (yield 86%) of a white solid. ______________________________________Amino Acid Analysis (nmol/50μ 1)______________________________________Arg 4.9877Gly 10.3916Asp 5.0199Ser 4.8891Mass Spectra: M.sup.+ 404______________________________________ Preparation Example 3: Synthesis of Peptide-6: H-(Gly-Arg-Gly-Asp-Ser-Pro)-OH (SEQ ID NO:6) Synthesis of this peptide was performed using a peptide synthesizer according to the Merrifield System. α-Amino groups were protected with Boc, the resulting peptide was purified by preparative HPLC after separating from the solid phase of a resin to give an adhesive synthetic peptide showing a single peak (yield 25%). Example 1: Synthesis of CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) There was dissolved, in a phosphate buffer of Ph 7.4, 0.30 g of a CM-chitin (available from Yaizu Fishery Chemical Industries, Ltd.) having a viscosity of 9 cps (1% solution at 20° C.), a degree of etherification of 0.78 and a degree of deacetylation of 0.5 and a solution of 128 mg of water-soluble DCC [1-ethyl-3,3-(dimethylaminopropyl)-carbodiimide] in 2.6 ml of a phosphate buffer was added thereto while maintaining the temperature at 0° C. to perform the reaction for 1.5 hour. Then a solution of 400 mg of an adhesive peptide: Arg-Gly-Asp-Ser (SEQ ID NO: 7) (available from Teikoku Chemical Industries Co., Ltd.) in 8 ml of a phosphate buffer was added to the reaction solution and the reaction was continued at 4° C. overnight. The reaction solution was packed in a Visking tube, purified through dialysis against deionized water and then pure water to remove the low molecular weight components and then lyophilized (yield 0.24 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. ______________________________________Amino Acid Analysis (nmol/50μ 1)______________________________________ glucosamine 20.5558 Arg 2.0556 Gly 2.1352 Asp 1.9854 Ser 1.8792______________________________________ The rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments was determined from the ratio of the concentration of arginine residue to that of glucosamine in accordance with the following relation and found to be about 10%. Rate of Introduction=[Arg] / [glucosamine]×100 IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 2: Synthesis of Succinylated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) There was dissolved, in 100 ml of a 1% triethylamine solution, 20.0 g of the CM-chitin used in Example 1, 34.0 g of succinic anhydride and 2.00 g of 4-dimethylaminopyridine were added to the resulting solution and the mixture was stirred at room temperature for a day and night. After completion of the reaction, the solution was poured into a large excess of acetone to again precipitate the succinylated CM-chitin. After collecting the precipitates, the precipitates were washed with a large amount of methanol and then ether and dried in vacuo. Yield=22.40 g. There was dissolved, in a phosphate buffer of Ph 7.4, 0.30 g of the succinylated CM-chitin and a solution of 128 mg of water-soluble DCC [1-ethyl-3,3-(dimethylaminopropyl)-carbodiimide] in 2.6 ml of a phosphate buffer was added thereto while maintaining the temperature at 0° C. to continue the reaction for 1.5 hour. Then a solution of 400 mg of Arg-Gly-Asp-Ser (SEQ ID NO:7) in 8 ml of a phosphate buffer was added to the reaction solution and the reaction was continued at 4° C. overnight. The reaction solution was packed in a Visking tube, purified through dialysis against deionized water and then pure water to remove the low molecular weight components and then lyophilized (yield 0.26 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 10%. The structural formula of the succinylated CM-chitin-Arg-Gly-Asp-Ser SEQ ID NO: 7) is as follows: ##STR1## ______________________________________Succinylated CM--Chitin Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 23.6218Arg 2.3622Gly 2.1253Asp 2.2391Ser 2.0031______________________________________ Stretching vibration of amidocarbonyl (C=O) 1652 cm.sup.-1 Example 3: Synthesis of Maleyl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 36.6 g of maleic anhydride were reacted to give 21.60 g of maleyl derivative of CM-chitin. The maleyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of Ph 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.33 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 11%. ______________________________________Maleyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 28.4956Arg 3.1345Gly 2.7751Asp 2.7213Ser 2.5694______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 4: Synthesis of Phthaloyl derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 50.0 g of phthalic anhydride were reacted to give 22.31 g of phthaloyl derivative of CM-chitin. The phthaloyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.44 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 12%. ______________________________________Phthaloyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1 )______________________________________glucosamine 19.1856Arg 2.3023Gly 2.2231Asp 1.8937Ser 1.7632______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 5: Synthesis of Itaconyl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 38.0 g of itaconic anhydride were reacted to give 21.45 g of itaconyl derivative of CM-chitin. The itaconyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.36 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 9%. ______________________________________Itaconyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 35.2316Arg 3.1708Gly 3.2511Asp 3.1005Ser 2.8862______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 6: Synthesis of Trimellityl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example I and 64.9 g of trimellitic anhydride were reacted to give 23.75 g of trimellityl derivative of CM-chitin. The trimellityl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.37 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 14%. ______________________________________Trimellityl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 18.7612Arg 2.6266Gly 2.7899Asp 2.5532Ser 2.2689______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1656 cm 31 1 Example 7: Synthesis of CM-Chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) The same procedures used in Example 1 were repeated except that 460 mg of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) (available from Kokusan Chemical Industries Co., Ltd.) was used as the cohesive peptide fragment to give 0.36 g of CM-chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 10%. ______________________________________CM--Chitin Gly--Arg--Gly--Asp--Ser (SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 15.3319Arg 1.5332Gly 3.2132Asp 1.3468Ser 1.1132______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 8: Synthesis of Succinylated CM-Chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) The same procedures used in Example 2 were repeated except that 460 mg of Gly-Arg-Gly-Asp-Ser was used as the adhesive peptide fragment to give 0.39 g of succinylated CM-chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 12%. ______________________________________Succinylated CM--Chitin-Gly--Arg--Gly--Asp--Ser(SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 30.3268Arg 3.6392Gly 7.0624Asp 3.5691Ser 3.3006______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 9: Synthesis of Succinylated CM-Chitin Arg-Gly-Asp (SEQ ID NO: 1) The same procedures were used in Example 2 were repeated except that 460 mg of Arg-Gly-Asp was used as the adhesive peptide fragment to give 0.34 of succinylated CM-chitin-Arg-Gly-Asp (SEQ ID NO: 1). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp (SEQ ID NO: 1) fragment was found to be about 16%. ______________________________________Succinylated CM--Chitin-Arg--Gly--Asp (SEQ ID NO: 1)Amino Acid Analysis (nmole.50μ 1)______________________________________glucosamine 27.8867Arg 4.4619Gly 4.5518Asp 4.4911______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 10: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 2 (SEQ ID NO: 2) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 2 (SEQ ID NO:2) was used as the cohesive peptide fragment to give 0.31 g of succinylated CM-chitin-(Arg-Gly-Asp) 2 (SEQ ID NO: 2). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 2 (SEQ ID NO: 2) fragment was found to be about 12%. ______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).sub.2 (SEQ ID NO: 2)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 25.1913Arg 6.0459Gly 5.9883Asp 5.8996______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 11: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 3 (SEQ ID NO: 3) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 3 (SEQ ID NO: 3) was used as the cohesive peptide fragment to give 0.33 g of succinylated CM-chitin-(Arg-Gly-Asp) 3 (SEQ ID NO: 3). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 3 (SEQ ID NO: 3) fragment was found to be about 10%. ______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).sub.3 (SEQ ID NO: 3)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 22.3161Arg 6.6949Gly 6.5132Asp 6.2323______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 12: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 5 (SEQ ID NO: 4) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 5 (SEQ ID NO: 4) was used as the cohesive peptide fragment to give 0.28 g of succinylated CM-chitin-(Arg-Gly-Asp) 5 (SEQ ID NO: 4). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 5 (SEQ ID NO: 4) fragment was found to be about 15%. ______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).sub.5 (SEQ ID NO: 4)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 23.6811Arg 23.0108Gly 21.0993Asp 20.3332______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1656 cm -1 Example 13: Synthesis of Sulfated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) A CM-chitin having a degree of etherification of 0.50 and a degree of deacetylation of 0.05 was sulfated according to the Tokura's method (Jpn. J. Cancer Res., 1989, 80, pp. 866-872; Cancer Res., 1990 50, pp. 3631-3637) and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the sulfated CM-chitin in the same manner were used in Example 1 (yield 0.36 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 12%. ______________________________________Sulfated CM--Chitin-Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 33.1569Arg 3.9780Gly 3.9251Asp 3.6053Ser 3.4921______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 14: Synthesis of Sulfated CM-Chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) In the same manner used in Example 1, 460 mg of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) and the sulfated CM-chitin obtained in Example 13 were covalently bonded to give 0.35 g of sulfated CM-chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 10%. ______________________________________Sulfated CM--Chitin-Gly--Arg--Gly--Asp--Ser (SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 25.1515Arg 2.51Gly 5.2134Asp 2.4251Ser 2.1111______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1655 cm -1 Example 15: Synthesis of Sulfated Succinylated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) In the same manner used in Example 13, the succinylated CM-chitin obtained in Example 2 was sulfated and Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded thereto in the same manner used in Example 2 (yield 0.37 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 14%. ______________________________________Sulfated Succinylated CM--Chitin-Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 18.6932Arg 2.6170Gly 2.7739Asp 2.5931Ser 2.2168______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 16: Synthesis of Sulfated Succinylated CM-Chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) In the same manner used in Example 13, the succinylated CM-chitin obtained in Example 2 was sulfated and Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragments were covalently bonded thereto in the same manner used in Example 7 (yield 0.31 g). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 17%. ______________________________________Sulfated Succinylated CM--Chitin Gly--Arg--Gly--Asp--Ser(SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 22.5661Arg 3.8362Gly 7.4963Asp 3.6811Ser 3.2593______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 17: Synthesis of CM-chitin-Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5) The same procedures used in Example 1 were repeated except that 460 mg of the peptide-5 (Arg-Gly-Asp-Ser-Gly-NH 2 ; Preparation Example 2) (SEQ ID NO: 5) was used as an adhesive peptide fragment to give 0.36 g of CM-chitin Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5) fragment was found to be about 10%. ______________________________________CM--Chitin-Arg--Gly--Asp--Ser--Gly--NH.sub.2 (SEQ ID NO: 5)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 17.6368Arg 1.8166Gly 3.8243Asp 1.8468Ser 1.6112______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1658 cm -1 Example 18: Synthesis of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 1 were repeated except that 1.5 g of Arg-Gly-Asp-Ser (SEQ ID NO: 7) was used as an adhesive peptide fragment to give 0.32 g of CM-chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 20%. ______________________________________CM--Chitin-Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 20.4598Arg 4.1052Gly 4.2688Asp 3.9808Ser 3.7784______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1655 cm -1 Example 19: Synthesis of CM-Chitin-Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6) The same procedures used in Example 1 were repeated except that 480 mg of Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6), i.e., the adhesive peptide fragment-6 (Preparation Example 3) was used as an adhesive peptide fragment to give 0.35 g of CM-chitin-Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6). The structure of the product was confirmed by IR and the analysis of amino acid sequence. As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6) fragment was found to be about 10%. ______________________________________CM--Chitin-Gly--Arg--Gly--Asp--Ser--Pro (SEQ ID NO: 6)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 15.3319Arg 1.5332Gly 3.2132Asp 1.3468Ser 1.1132Pro 1.3326______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1657 cm -1 Test Example 1: Determination of Cell Adhesion-Inhibitory Activity A method for determining the activity of the CM-chitin derivatives of the present invention for inhibiting adhesion of cells to fibronectin or vitronectin will be described below. The competitive assays used herein have widely been employed tin the field of biochemistry and are detailed in, for instance, "Method in Enzymology", 1981, 82, pp. 803-831; and J. P. KOKAI Nos. Hei 1-309682 and Hei 2-174797. EXPERIMENTAL METHOD 1. Preparation of Adsorption Plate Commercially available fibroneotin (derived from human; purchased from Seikaqaku Kogyo K. K.) and vitronectin (derived from human; purchased from Funakoshi Co., Ltd.) each was diluted to 1.0 μ1/ml and 2.0 μ1/ml with PBS (NaH 2 PO 4 0.005 M+NaCl 0.07 M), 0.5 ml of the resulting diluted solution was dispensed into a plastic plate having 24 wells and incubated at 37° C. overnight to perform coating of the plate. Then bovine serum albumin (BSA 1%) was added followed by incubation at 37° C. for one hour for inhibiting the occurrence of nonspecific adsorption, then washing with PBS in the usual manner and sufficient drainage to give an adsorption plate. 2. Adhesion-Inhibitory Test A CM-chitin derivative obtained through lyophilization was diluted with Dulbecco's Modified Eagles Medium (hereunder referred to as "DMEM") to give solutions of the CM-chitin derivative having concentrations of 0, 0.25, 0.5, 1.0 and 1.5 mg/ml respectively. Each of the solutions (0.25 ml) was dispensed to the plate prepared above, 0.25 ml of a suspension of endothelium cells of blood vessel (4×10 6 cells/ml) was added to the plate and incubated at 37° C. for one hour to thus cause cohesion of the cells. The plate was washed three times with DMEM medium to remove non-adhesive cells, then the adhered cells were peeled off with a 0.025% EDTA trypsin solution and stained with a 2% Trypan Blue solution to determine the number of the adhered cells. The results thus obtained are summarized in the following Tables 1 and 2. TABLE 1______________________________________Cell Adhesion-Inhibitory effect Against Fibronectin (cell/well) Concentration (mg/ml)Compound Added 0 .25 0.5 1.0 1.5______________________________________CM--chitin 160 171 157 165 152CM--chitin derivative-1 160 131 106 79 69CM--chitin derivative-2 160 135 99 82 75CM--chitin derivative-3 160 123 100 77 55CM--chitin derivative-4 160 141 121 80 67CM--chitin derivative-5 160 136 105 86 72CM--chitin derivative-6 160 127 107 93 66CM--chitin derivative-7 160 119 98 84 71CM--chitin derivative-8 160 130 113 80 59CM--chitin derivative 9 160 121 97 85 65CM--chitin derivative-10 160 122 110 87 73CM--chitin derivative-11 160 143 125 78 70CM--chitin derivative-12 160 125 101 89 77Sulfated CM--chitin 160 150 155 147 141CM--chitin derivative-13 160 97 77 57 33CM--chitin derivative-14 160 111 93 68 41CM--chitin derivative-15 160 105 89 65 37CM--chitin derivative-16 160 103 81 75 50CM--chitin derivative-17 160 99 84 61 35CM--chitin derivative-18 160 133 101 75 52CM--chitin derivative-19 160 127 106 79 56ArgGlyAsp 160 157 162 141 83(SEQ ID NO: 1)GlyArgGlyAspSer 160 154 140 95 80(SEQ ID NO: 8)______________________________________ TABLE 2______________________________________Cell Adhesion-Inhibitory effect Against Vitronectin (cell/well) Concentration (mg/ml)Compound Added 0 10 50 100 300______________________________________CM--chitin 249 260 243 240 255CM--chitin derivative-1 249 148 89 72 41CM--chitin derivative-2 249 137 96 78 59CM--chitin derivative-3 249 141 87 69 49CM--chitin derivative-4 249 145 90 67 45CM--chitin derivative-5 249 129 91 80 48CM--chitin derivative-6 249 133 98 71 56CM--chitin derivative-7 249 143 85 79 55CM--chitin derivative-8 249 130 95 69 47CM--chitin derivative-9 249 139 88 77 58CM--chitin derivative-10 249 136 86 71 43CM--chitin derivative-11 249 147 100 73 45CM--chitin derivative-12 249 150 101 80 59Sulfated CM--chitin 249 231 235 222 200CM--chitin derivative-13 249 103 70 47 31CM--chitin derivative-14 249 107 78 43 34CM--chitin derivative-15 249 115 69 54 38CM--chitin derivative-16 249 122 81 63 40CM--chitin derivative-17 249 114 76 48 33CM--chitin derivative-18 249 125 83 56 44CM--chitin derivative-19 249 130 92 63 39ArgGlyAsp 249 171 132 104 73(SEQ ID NO: 1)GlyArgGlyAspSer 249 157 116 87 61(SEQ lD NO: 8)______________________________________ Test Example 2: Determination of Platelet Coagulation-Inhibitory Activity The platelet coagulation-inhibitory effect of the CM-chitin derivative of the present invention was assayed, in vitro, using human plasma rich in platelet. The experimental method will be described below. EXPERIMENTAL METHOD To fresh human blood, there was added 1/9 volume of a 3.8% sodium citrate solution, the resulting mixture was centrifuged (1000 rpm; for 10 minutes) and the upper layer was separated as a plasma rich in platelet. A lyophilized CM-chitin derivative was dissolved in physiological saline to give a plurality of solutions having various concentrations ranging from 0 to 1.5 mg/ml. Each of the solutions (25 μ1) was added to 200 μ1 of the plasma, incubated at 37° C. for 3 minutes, then a 50 μM of ADP (adenosine diphosphate) solution or a 200 μg/ml collagen solution was added to determine the extent of coagulation in terms of transmittance determined by an aggregometer. The results thus obtained are listed in the following Table 3. Rate of Coagulation Inhibition=(1-T/T .)×100% T . : transmittance observed when a salt of CM-chitin derivative was not added. T : transmittance observed when a salt of CM-chitin derivative was added. TABLE 3______________________________________Platelet Coagulation-Inhibitory Action IC.sub.50 (μg/ml) ADP CollagenCompound Added Stimulation Stimulation______________________________________CM--chitin 96 90CM--chitin derivative-1 15 10CM--chitin derivative-2 18 10CM--chitin derivative-3 21 7CM--chitin derivative-4 29 15CM--chitin derivative-5 17 12CM--chitin derivative-6 26 11CM--chitin derivative-7 30 16CM--chitin derivative-8 24 14CM--chitin derivative-9 28 9CM--chitin derivative-10 20 13CM--chitin derivative-11 21 12CM--chitin derivative-12 30 8Sulfated CM--chitin 72 61CM--chitin derivative-13 17 7CM--chitin derivative-14 12 3CM--chitin derivative-15 15 6CM--chitin derivative-16 12 2CM--chitin derivative-17 14 5CM--chitin derivative-18 21 10CM--chitin derivative-19 19 5ArgGlyAsp 27 22(SEQ ID NO: 1)GlyArgGlyAspSer 31 18(SEQ ID NO: 8)______________________________________ __________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 9(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 3 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:ArgGlyAsp(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 6 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:ArgGlyAspArgGlyAsp15(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:ArgGlyAspArgGlyAspArgGlyAsp15(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 15 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:ArgGlyAspArgGlyAspArgGlyAspArgGlyAspArgGlyAsp151015(2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 5 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:ArgGlyAspSerGly15(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 6 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:GlyArgGlyAspSerPro15(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 4 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:ArgGlyAspSer1(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 5 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:GlyArgGlyAspSer1 5(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 4 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:GlyAspSerGly1
A CM-chitin derivative which has, as an essential unit, a cohesive peptide represented by the following general formula (I), bonded to the side chain of CM-chitin, wherein the bond connecting CM-chitin and said peptide is selected from the group consisting of an amido bond, an ester bond, an ether bond and a urethane bond: -[R.sup.1 ]-[CO]-([X]-Arg-Gly-Asp-[Y]).sub.n -[Z]-[R.sup.2 ]- . . . (I)(SEQ ID NO:1) wherein the bracket [ ] means that the corresponding group or residue may be present or absent and if they are present, X and Y each represents an amino acid residue selected from the group consisting of Ser, Gly, Val, Asn and Pro or a peptide residue; Z represents --O-- or --NH--; one of R 1 and R 2 represents a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms or aryl group having 6 to 9 carbon atoms and the other represents a hydrogen atom, a linear or branched alkylene group having 1 to 9 carbon atoms or an arylene group having 6 to 9 carbon atoms wherein the alkylene and arylene groups may have substituents; and n is an integer ranging from 1 to 5. The derivative or salt thereof is useful as an effective component of compositions for inhibiting adhesion of animal cells or for inhibiting coagulation of blood platelets.
Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function.
[ "BACKGROUND OF THE INVENTION The present invention relates to CM-chitin derivatives having a tripeptide, Arg-Gly-Asp (SEQ ID NO: 1), as an essential unit, and salts thereof, as well as a composition for inhibiting adhesion of animal cells and a composition for inhibiting coagulation of blood platelets.", "Fibronectin is a protein involved in the cell-extracellular substrate adhesion and is likewise thought to be involved in coagulation of blood platelets and the metastasis of cancer.", "These interactions are mediated by a series of receptors present in the cell surface region.", "It is confirmed that these receptors can specifically recognize an amino acid sequence: Arg-Gly-Asp (SEQ ID NO: 1) of the fibronectin although the fibronectin is a macromolecule having a molecular weight of about 250,000 and it has been reported that the sequence plays an important role in the interaction between the receptors and the fibronectin (Nature, 1984, 309, p. 30).", "Since then, there have been many studies conducted in which an oligopeptide or polypeptide having such an amino acid sequence: Arg-Gly-Asp (SEQ ID NO: 1) is used.", "There have been various studies reported, such as a method for inhibiting the coagulation of blood platelets by the use of various linear and cyclic oligopeptides having an Arg-Gly-Asp (SEQ ID NO: 1) sequence (Polymer Preprints, Japan, 1989, 38, p. 3149;", "Japanese Unexamined Patent Publication (hereinafter referred to as "J.", "P. KOKAI") No. Hei 2-174797);", "a method in which a peptide having an Arg-Gly-Asp (SEQ ID NO: 1) sequence is used as a cell movement-inhibiting agent (J.", "P. KOKAI No. Hei 2-4716);", "and a method using as a cell-adhesive membrane, a PMMA film on which Arg-Gly-Asp (SEQ ID NO: 1) sequences are immobilized (Polymer Preprints, Japan, 1988, 37, p. 705).", "In addition, J. P. KOKAI Nos. Hei 1-309682 and Hei 1-305960 disclose a method which comprises peptides having Arg-Gly-Asp (SEQ ID NO: 1) sequences as essential structural units covalently bonded to a polymer and the resulting product is used as a substrate for cultivating animal cells or for biological composite artificial organs and J. P. KOKAI No. Sho 64-6217 discloses a method in which a polypeptide having Arg-Gly-Asp-Ser (SEQ ID NO: 7) sequences is used as a platelet protective agent for blood taken out of the body.", "Further, there is a known method comprising inhibiting the metastasis of cancer by the use of an oligopeptide having Arg-Gly-Asp (SEQ ID NO: 1) sequences or a polypeptide having the sequence as repeating units (Int.", "J. Biol.", "Macromol.", ", 1989, 11, p. 23;", "ibid, 1989, 11, p. 226;", "Jpn.", "J. Cancer Res.", ", 1989, 60, p. 722).", "Chitin is a polysaccharide in which N-acetyl-D-glucosamine is linked through the β- (1→4) bond and is a main component of the exoskeleton of Crustacea and Insects.", "It is widely distributed in lower animals and invertebrates and serves to support and/or protect the organs.", "The functions thereof correspond to those of cellulose in the plant.", "Chitin is also called the last biomass, derivatives thereof have been variously studied recently and, in particular, many studies concerning solvent-soluble chitin derivatives have been reported.", "Among them, CM-chitin in which a carboxymethyl group is bonded to the C-6 hydroxyl group is water-soluble and a very important compound as a starting material for preparing various chitin derivatives.", "Chitin and derivatives thereof are detailed in "Applications of Chitin Chitosan", edited by the Society for research of chitin chitosan published by Gihodo Publishing Company and "The Last Biomass: Chitin Chitosan", edited by the same Society, published by Gihodo Publishing Company.", "The CM-chitin causes deacetylation during carboxylation and this indicates the presence of an amino group in addition to a carboxyl group.", "The amino group thereof can easily undergo carboxylation with a dibasic acid or a derivative thereof, preferably a polybasic acid anhydride.", "The N, O-sulfation of the CM-chitin is also easy.", "However, there is no known compound in which an oligopeptide having an Arg-Gly-Asp (SEQ ID NO: 1) sequence as an essential unit or a polypeptide having the sequences as repeating unit.", "If such an oligopeptide or a polypeptide is introduced into a compound, it would be expected that the ability of bonding thereof to a receptor and the stability thereof in blood would be greatly enhanced.", "Accordingly, an object of the present invention is to provide a novel CM-chitin derivative.", "Another object of the present invention is to provide a composition for inhibiting adhesion of animal cells containing the chitin derivative as an effective component.", "A further object of the present invention is to provide a composition for suppressing coagulation of blood platelets which comprises the novel CM-chitin derivative as an effective component.", "According to an aspect of the present invention, a CM-chitin derivative is provided having, as an essential structural unit, an adhesive peptide represented by the following general formula (I) through any one of an amido bond, an ester bond, an ether bond and a urethane bond on the side chain and salts thereof: -[R.", "sup[.", "].1 ]-[CO]-([X]-Arg-Gly-Asp-[Y]).", "sub.", "n -[Z]-[R.", "sup[.", "].2 ]--.", "(I) (SEQ ID NO: 1) In general formula (I), [ ] means that each corresponding group or residue may be present or absent and if they are present, X and Y each represents an amino acid residue selected from the group consisting of Ser, Gly, Val, Asn and Pro or a peptide residue consisting of two or more of the amino acids;", "Z represents --O-- or --NH--;", "one of R 1 and R 2 represents a hydrogen atom, a linear or branched alkyl group having 1 to 9 carbon atoms or an aryl group having 6 to 9 carbon atoms in which the alkyl and aryl groups may be substituted and the other represents a hydrogen atom, a linear or branched alkylene group having 1 to 9 carbon atoms or an arylene group having 6 to 9 carbon atoms wherein the alkylene and arylene groups may be substituted;", "and n is an integer ranging from 1 to 5.", "Examples of substituents for R 1 and R 2 include halogen atoms, carbonyl, carboxyl, amino, hydroxyl, sulfo, aryl, nitro and cyano groups, unsaturated hydrocarbon group which has a double bond and triple bond and they may have two or more substituents.", "According to another aspect of the present invention, there is provided a composition for inhibiting adhesion of animal cells or for suppressing coagulation of blood platelets comprising the foregoing CM-chitin derivative as an effective component.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a CM-chitin derivative in which an adhesive peptide having, as an essential unit, an Arg-Gly-Asp (SEQ ID No: 1) sequence is covalently bonded to a sulfated CM-chitin, carboxylated CM-chitin or CM-chitin.", "The molecular weight of the CM-chitin derivatives is not more than 200,000, in particular, 3,000 to 100,000 and the derivative is preferably soluble in water at room temperature.", "Examples of carboxylating agents used herein are succinic anhydride, maleic anhydride, phthalic anhydride, itaconic anhydride, citraconic anhydride, pyromellitic anhydride and trimellitic anhydride.", "Amino acids used in the adhesive peptide may be either L- or D-isomers and preferably L-isomers.", "Examples of the salts of the CM-chitin derivatives of the invention are those with inorganic acids such as hydrochlorides, sulfates, nitrates, phosphates and borates;", "and those with organic acid s such as acetates, trifluoroacetates, trifluoromethanesulfonates, lactates and tartrates.", "Methods for synthesizing these peptides are not restricted to specific ones and may be liquid phase and solid phase methods and those in which an automatic synthesizer is employed.", "These synthesis methods are detailed in, for instance, Lectures on Biochemical Experiments, "Chemistry of Proteins IV", pp. 207-495, edited by Biochemical Society of Japan, published by Tokyo Kagaku Dojin Publishing Company;", "Lectures on Biochemical Experiments, Second Series, "Chemistry of Proteins (the last volume)", edited by Biochemical Society of Japan, published by Tokyo Kagaku Dojin Publishing Company;", "and "Fundamental Knowledge and Experiments of Peptide Synthesis", edited by Izumiya et al.", ", published by Maruzen Publishing Company.", "Alternatively, it is also possible to use commercially available synthetic peptides.", "Amide bond-forming methods in which agents such as cyanogen bromide, acid azides or water-soluble carbodiimides can be used for coupling the CM-chitin or carboxylated CM-chitin with an adhesive peptide.", "The CM-chitin derivatives of the invention have a core sequence: Arg-Gly-Asp (SEQ ID No: 1) of a cell-cohesive protein and are adhered to cells through the core sequence according to a mechanism similar to that for the cell-adhesive protein.", "For this reason, they serve as agonists or antagonists of the cell-adhesive protein which exhibit a variety of biological activities such as immunoregulating action, wound-healing action, action for inhibiting platelet coagulation observed in blood vessels and nervous disorder-healing action.", "Thus, at least one of the CM-chitin derivatives of the invention can be administered to patients together with commonly used optional carriers or pharmaceutical auxiliary agents in the form of wound-healing agents, immunoregulating agents or platelet coagulation-inhibiting agents.", "In particular, the derivatives are preferably used as animal cell adhesion-inhibiting agents or platelet coagulation-inhibiting agents.", "The dose thereof varies depending on various factors such as conditions to be treated, age and weight of patients and generally ranges from 0.2 μg/kg to 400 mg/kg.", "The CM-chitin derivatives may be administered through various routes which are generally used for the administration of peptide-containing medicines.", "For instance, they are preferably administered parenterally, intravenously, intramuscularly and subcutaneously.", "In the preparation of injectable pharmaceutical preparations containing the same, the chitin derivative is dissolved in, for instance, PBS or physiological saline to give an injectable solution.", "These pharmaceutical preparations may comprise a commonly used stabilizer such as glycine and albumin.", "Moreover, the chitin derivative may be parenterally administered by encapsulating them in liposomes to give microcapsules.", "Further, if they are formulated in the form of, for instance, suppository, sublingual tablets and nasal sprays, they can be absorbed through mucous other than digestive tracts.", "The present invention will hereinafter be explained in more detail with reference to the following non-limitative working Examples and Preparation Examples, but the present invention is by no means limited to these specific Examples.", "Preparation Example 1: Synthesis of Cohesive Peptide by Solid Phase Method Synthesis of this peptide was performed using a peptide synthesizer according to the Merrifield System.", "α- Amino groups were protected with Boc, the resulting peptide was purified by preparative high performance liquid chromatography (HPLC) after separating from the solid phase of a resin to give an adhesive synthetic peptide showing a single peak.", "______________________________________Adhesive Peptides SynthesizedName Structural Formula Sequence No. Yield______________________________________Pep- H--(Arg--Gly--Asp)--OH (SEQ ID NO: 1) 37%tide-1Pep- H--(Arg--Gly--Asp).", "sub[.", "].2 --OH (SEQ ID NO: 2) 28%tide-2Pep- H--(Arg--Gly--Asp).", "sub[.", "].3 --OH (SEQ ID NO: 3) 19%tide-3Pep- H--(Arg--Gly--Asp).", "sub[.", "].5 --OH (SEQ ID NO: 4) 11%tide-4______________________________________ Preparation Example 2: Syntheses of Peptide-5: H-(Arg-Gly-Asp-Ser-Gly)-NH 2 (SEQ ID NO: 5) The peptide-5 was prepared by a liquid phase method according to a sequential-extension method.", "(1) Synthesis of Boc Ser(Bzl)GlyNH 2 To 400 ml of CH 2 Cl 2 , there was dissolved 59 g (0.2 mole) of Boc Ser(Bzl) and then 41.2 g (0.2 mole) of DCC was added thereto with ice-cooling.", "A solution of 22.1 g of GlyNH 2 .", "HC1 in 400 ml of CH 2 C1 2 which was then neutralized by the addition of 20.2 g of N-methylmorpholine under ice-cooling was added to the resulting solution.", "The mixture was stirred for 3 hours under ice-cooling and then at room temperature overnight.", "After separating precipitates formed by filtration, the filtrate was concentrated under reduced pressure and then the residue obtained was dissolved in ethyl acetate.", "The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 58.3 g (yield 83%) of a product as white powder.", "(2) Synthesis of BocAsp(OBzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 1) There was added 400 ml of TFA/CH 2 C1 2 (=1/1) to 56.2 g (0.16 mole) of BocSer((Bzl)GlyNH 2 , the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl.", "After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure.", "There were dissolved the resulting compound and 51 7 g (0.16 mole) of BocAsp (Obzl) in 800 ml of CH 2 Cl 2 followed by addition of 33 g (0.16 mole) of DCC under ice-cooling, stirring for 3 hours and further at room temperature overnight.", "After distilling off the CH 2 Cl 2 under reduced pressure, the resulting residue was dissolved in ethyl acetate.", "The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 71.2 g (yield 80%) of a product as white powder.", "(3) Synthesis of BocGlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 9) There was added 400 ml of TFA/CH 2 Cl 2 (=1/1) to 66.7 g (0.12 mole) of BocAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 1), the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl.", "After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure.", "There were dissolved the resulting compound and 51.7 g (0.12 mole) of BocGly in 700 ml of CH 2 Cl 2 followed by addition of 24.7 g (0.12 mo)e) of DCC under ice-cooling, stirring for 3 hours and further at room temperature overnight.", "After removing the resulting DCurea by filtration and distilling off the CH 2 Cl 2 under reduced pressure, the resulting residue was dissolved in ethyl acetate.", "The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 61.8 g (yield 84%) of a product as white powder.", "Synthesis of BocArg(Mts)GlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 5) There was added 400 ml of TFA/CH 2 Cl 2 (=1/1) to 61.3 g (0.1 mole) of BocGlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO: 9), the resulting mixture was stirred at room temperature for one hour and the TFA and CH 2 Cl 2 were removed by concentration under reduced pressure followed by dissolution in ethyl acetate, neutralization with an aqueous solution of NaHCO 3 and washing with an aqueous solution of NaCl.", "After drying the solution over Na 2 SO 4 , the ethyl acetate was removed by distillation under reduced pressure.", "There was dissolved the resulting compound and 45.6 g (0.1 mole) of BocArg(Mts) (Mts: a mesitylene-2-sulfonyl group) in 800 ml of DMF followed by addition of 22.5 g (0.1 mole) of DCC and 14 g (0.1 mole) of HOBt under ice-cooling, stirring for 3 hours and further at room temperature overnight.", "After removing the resulting Dcurea by filtration and distilling off the solvent under reduced pressure, the resulting residue was dissolved in ethyl acetate.", "The solution was washed, in turn, with an NaHCO 3 aqueous solution, 1M citric acid aqueous solution and then an NaCl aqueous solution, dried over Na 2 SO 4 and evaporated to dryness under reduced pressure to give 42.8 g (yield 45%) of a product as white powder.", "(5) Removal of Protective Groups (Synthesis of Peptide-5) To a solution of BocArg(Mts)GlyAsp(Obzl)Ser((Bzl)GlyNH 2 (SEQ ID NO:5) (5 g;", "5.3 Mm) in TFA, there was added, under ice-cooling, a 1M solution of trifluoromethanesulfonic acid-thioanisole-m-cresol in TFA to react these for one hour and then the protective groups present on the side chains and termini of the peptide were removed.", "The reaction solution was poured into ether, the resulting oily precipitates were dissolved in distilled water, then washed with ethyl acetate, passed through a column packed with an anion-exchange resin (Amberlite IRA-400Cl Type) to thus convert into hydrochloride and lyophilized to give 2.17 g (yield 86%) of a white solid.", "______________________________________Amino Acid Analysis (nmol/50μ 1)______________________________________Arg 4.9877Gly 10.3916Asp 5.0199Ser 4.8891Mass Spectra: M.sup.", "+ 404______________________________________ Preparation Example 3: Synthesis of Peptide-6: H-(Gly-Arg-Gly-Asp-Ser-Pro)-OH (SEQ ID NO:6) Synthesis of this peptide was performed using a peptide synthesizer according to the Merrifield System.", "α-Amino groups were protected with Boc, the resulting peptide was purified by preparative HPLC after separating from the solid phase of a resin to give an adhesive synthetic peptide showing a single peak (yield 25%).", "Example 1: Synthesis of CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) There was dissolved, in a phosphate buffer of Ph 7.4, 0.30 g of a CM-chitin (available from Yaizu Fishery Chemical Industries, Ltd.) having a viscosity of 9 cps (1% solution at 20° C.), a degree of etherification of 0.78 and a degree of deacetylation of 0.5 and a solution of 128 mg of water-soluble DCC [1-ethyl-3,3-(dimethylaminopropyl)-carbodiimide] in 2.6 ml of a phosphate buffer was added thereto while maintaining the temperature at 0° C. to perform the reaction for 1.5 hour.", "Then a solution of 400 mg of an adhesive peptide: Arg-Gly-Asp-Ser (SEQ ID NO: 7) (available from Teikoku Chemical Industries Co., Ltd.) in 8 ml of a phosphate buffer was added to the reaction solution and the reaction was continued at 4° C. overnight.", "The reaction solution was packed in a Visking tube, purified through dialysis against deionized water and then pure water to remove the low molecular weight components and then lyophilized (yield 0.24 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "______________________________________Amino Acid Analysis (nmol/50μ 1)______________________________________ glucosamine 20.5558 Arg 2.0556 Gly 2.1352 Asp 1.9854 Ser 1.8792______________________________________ The rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments was determined from the ratio of the concentration of arginine residue to that of glucosamine in accordance with the following relation and found to be about 10%.", "Rate of Introduction=[Arg] / [glucosamine]×100 IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 2: Synthesis of Succinylated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) There was dissolved, in 100 ml of a 1% triethylamine solution, 20.0 g of the CM-chitin used in Example 1, 34.0 g of succinic anhydride and 2.00 g of 4-dimethylaminopyridine were added to the resulting solution and the mixture was stirred at room temperature for a day and night.", "After completion of the reaction, the solution was poured into a large excess of acetone to again precipitate the succinylated CM-chitin.", "After collecting the precipitates, the precipitates were washed with a large amount of methanol and then ether and dried in vacuo.", "Yield=22.40 g. There was dissolved, in a phosphate buffer of Ph 7.4, 0.30 g of the succinylated CM-chitin and a solution of 128 mg of water-soluble DCC [1-ethyl-3,3-(dimethylaminopropyl)-carbodiimide] in 2.6 ml of a phosphate buffer was added thereto while maintaining the temperature at 0° C. to continue the reaction for 1.5 hour.", "Then a solution of 400 mg of Arg-Gly-Asp-Ser (SEQ ID NO:7) in 8 ml of a phosphate buffer was added to the reaction solution and the reaction was continued at 4° C. overnight.", "The reaction solution was packed in a Visking tube, purified through dialysis against deionized water and then pure water to remove the low molecular weight components and then lyophilized (yield 0.26 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 10%.", "The structural formula of the succinylated CM-chitin-Arg-Gly-Asp-Ser SEQ ID NO: 7) is as follows: ##STR1## ______________________________________Succinylated CM--Chitin Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 23.6218Arg 2.3622Gly 2.1253Asp 2.2391Ser 2.0031______________________________________ Stretching vibration of amidocarbonyl (C=O) 1652 cm.", "sup.", "-1 Example 3: Synthesis of Maleyl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 36.6 g of maleic anhydride were reacted to give 21.60 g of maleyl derivative of CM-chitin.", "The maleyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of Ph 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.33 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 11%.", "______________________________________Maleyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 28.4956Arg 3.1345Gly 2.7751Asp 2.7213Ser 2.5694______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 4: Synthesis of Phthaloyl derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 50.0 g of phthalic anhydride were reacted to give 22.31 g of phthaloyl derivative of CM-chitin.", "The phthaloyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.44 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 12%.", "______________________________________Phthaloyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1 )______________________________________glucosamine 19.1856Arg 2.3023Gly 2.2231Asp 1.8937Ser 1.7632______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 5: Synthesis of Itaconyl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example 1 and 38.0 g of itaconic anhydride were reacted to give 21.45 g of itaconyl derivative of CM-chitin.", "The itaconyl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.36 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 9%.", "______________________________________Itaconyl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 35.2316Arg 3.1708Gly 3.2511Asp 3.1005Ser 2.8862______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 6: Synthesis of Trimellityl Derivative of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 2 were repeated except that 20.00 g of the CM-chitin obtained in Example I and 64.9 g of trimellitic anhydride were reacted to give 23.75 g of trimellityl derivative of CM-chitin.", "The trimellityl derivative of CM-chitin (0.30 g) was dissolved in a phosphate buffer of pH 7.4 and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the CM-chitin derivative in the same manner used in Example 2 (yield 0.37 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 14%.", "______________________________________Trimellityl Derivative of CM--Chitin Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 18.7612Arg 2.6266Gly 2.7899Asp 2.5532Ser 2.2689______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1656 cm 31 1 Example 7: Synthesis of CM-Chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) The same procedures used in Example 1 were repeated except that 460 mg of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) (available from Kokusan Chemical Industries Co., Ltd.) was used as the cohesive peptide fragment to give 0.36 g of CM-chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 10%.", "______________________________________CM--Chitin Gly--Arg--Gly--Asp--Ser (SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 15.3319Arg 1.5332Gly 3.2132Asp 1.3468Ser 1.1132______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 8: Synthesis of Succinylated CM-Chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) The same procedures used in Example 2 were repeated except that 460 mg of Gly-Arg-Gly-Asp-Ser was used as the adhesive peptide fragment to give 0.39 g of succinylated CM-chitin Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 12%.", "______________________________________Succinylated CM--Chitin-Gly--Arg--Gly--Asp--Ser(SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 30.3268Arg 3.6392Gly 7.0624Asp 3.5691Ser 3.3006______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 9: Synthesis of Succinylated CM-Chitin Arg-Gly-Asp (SEQ ID NO: 1) The same procedures were used in Example 2 were repeated except that 460 mg of Arg-Gly-Asp was used as the adhesive peptide fragment to give 0.34 of succinylated CM-chitin-Arg-Gly-Asp (SEQ ID NO: 1).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp (SEQ ID NO: 1) fragment was found to be about 16%.", "______________________________________Succinylated CM--Chitin-Arg--Gly--Asp (SEQ ID NO: 1)Amino Acid Analysis (nmole[.", "].50μ 1)______________________________________glucosamine 27.8867Arg 4.4619Gly 4.5518Asp 4.4911______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 10: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 2 (SEQ ID NO: 2) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 2 (SEQ ID NO:2) was used as the cohesive peptide fragment to give 0.31 g of succinylated CM-chitin-(Arg-Gly-Asp) 2 (SEQ ID NO: 2).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 2 (SEQ ID NO: 2) fragment was found to be about 12%.", "______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).", "sub[.", "].2 (SEQ ID NO: 2)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 25.1913Arg 6.0459Gly 5.9883Asp 5.8996______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 11: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 3 (SEQ ID NO: 3) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 3 (SEQ ID NO: 3) was used as the cohesive peptide fragment to give 0.33 g of succinylated CM-chitin-(Arg-Gly-Asp) 3 (SEQ ID NO: 3).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 3 (SEQ ID NO: 3) fragment was found to be about 10%.", "______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).", "sub[.", "].3 (SEQ ID NO: 3)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 22.3161Arg 6.6949Gly 6.5132Asp 6.2323______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1648 cm -1 Example 12: Synthesis of Succinylated CM-Chitin-(Arg-Gly-Asp) 5 (SEQ ID NO: 4) The same procedures used in Example 2 were repeated except that 460 mg of (Arg-Gly-Asp) 5 (SEQ ID NO: 4) was used as the cohesive peptide fragment to give 0.28 g of succinylated CM-chitin-(Arg-Gly-Asp) 5 (SEQ ID NO: 4).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of (Arg-Gly-Asp) 5 (SEQ ID NO: 4) fragment was found to be about 15%.", "______________________________________Succinylated CM--Chitin-(Arg--Gly--Asp).", "sub[.", "].5 (SEQ ID NO: 4)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 23.6811Arg 23.0108Gly 21.0993Asp 20.3332______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1656 cm -1 Example 13: Synthesis of Sulfated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) A CM-chitin having a degree of etherification of 0.50 and a degree of deacetylation of 0.05 was sulfated according to the Tokura's method (Jpn.", "J. Cancer Res.", ", 1989, 80, pp. 866-872;", "Cancer Res.", ", 1990 50, pp. 3631-3637) and then Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded to the sulfated CM-chitin in the same manner were used in Example 1 (yield 0.36 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 12%.", "______________________________________Sulfated CM--Chitin-Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 33.1569Arg 3.9780Gly 3.9251Asp 3.6053Ser 3.4921______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1650 cm -1 Example 14: Synthesis of Sulfated CM-Chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) In the same manner used in Example 1, 460 mg of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) and the sulfated CM-chitin obtained in Example 13 were covalently bonded to give 0.35 g of sulfated CM-chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 10%.", "______________________________________Sulfated CM--Chitin-Gly--Arg--Gly--Asp--Ser (SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 25.1515Arg 2.51Gly 5.2134Asp 2.4251Ser 2.1111______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1655 cm -1 Example 15: Synthesis of Sulfated Succinylated CM-Chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7) In the same manner used in Example 13, the succinylated CM-chitin obtained in Example 2 was sulfated and Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragments were covalently bonded thereto in the same manner used in Example 2 (yield 0.37 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 14%.", "______________________________________Sulfated Succinylated CM--Chitin-Arg--Gly--Asp--Ser(SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 18.6932Arg 2.6170Gly 2.7739Asp 2.5931Ser 2.2168______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1654 cm -1 Example 16: Synthesis of Sulfated Succinylated CM-Chitin-Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) In the same manner used in Example 13, the succinylated CM-chitin obtained in Example 2 was sulfated and Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragments were covalently bonded thereto in the same manner used in Example 7 (yield 0.31 g).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser (SEQ ID NO: 8) fragment was found to be about 17%.", "______________________________________Sulfated Succinylated CM--Chitin Gly--Arg--Gly--Asp--Ser(SEQ ID NO: 8)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 22.5661Arg 3.8362Gly 7.4963Asp 3.6811Ser 3.2593______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1652 cm -1 Example 17: Synthesis of CM-chitin-Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5) The same procedures used in Example 1 were repeated except that 460 mg of the peptide-5 (Arg-Gly-Asp-Ser-Gly-NH 2 ;", "Preparation Example 2) (SEQ ID NO: 5) was used as an adhesive peptide fragment to give 0.36 g of CM-chitin Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser-Gly-NH 2 (SEQ ID NO: 5) fragment was found to be about 10%.", "______________________________________CM--Chitin-Arg--Gly--Asp--Ser--Gly--NH.", "sub[.", "].2 (SEQ ID NO: 5)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 17.6368Arg 1.8166Gly 3.8243Asp 1.8468Ser 1.6112______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1658 cm -1 Example 18: Synthesis of CM-Chitin Arg-Gly-Asp-Ser (SEQ ID NO: 7) The same procedures used in Example 1 were repeated except that 1.5 g of Arg-Gly-Asp-Ser (SEQ ID NO: 7) was used as an adhesive peptide fragment to give 0.32 g of CM-chitin-Arg-Gly-Asp-Ser (SEQ ID NO: 7).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Arg-Gly-Asp-Ser (SEQ ID NO: 7) fragment was found to be about 20%.", "______________________________________CM--Chitin-Arg--Gly--Asp--Ser (SEQ ID NO: 7)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 20.4598Arg 4.1052Gly 4.2688Asp 3.9808Ser 3.7784______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1655 cm -1 Example 19: Synthesis of CM-Chitin-Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6) The same procedures used in Example 1 were repeated except that 480 mg of Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6), i.e., the adhesive peptide fragment-6 (Preparation Example 3) was used as an adhesive peptide fragment to give 0.35 g of CM-chitin-Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6).", "The structure of the product was confirmed by IR and the analysis of amino acid sequence.", "As a result of the amino acid sequence analysis, the rate of introduction of Gly-Arg-Gly-Asp-Ser-Pro (SEQ ID NO: 6) fragment was found to be about 10%.", "______________________________________CM--Chitin-Gly--Arg--Gly--Asp--Ser--Pro (SEQ ID NO: 6)Amino Acid Analysis (nmole/50μ 1)______________________________________glucosamine 15.3319Arg 1.5332Gly 3.2132Asp 1.3468Ser 1.1132Pro 1.3326______________________________________ IR: stretching vibration of amidocarbonyl (C=O) 1657 cm -1 Test Example 1: Determination of Cell Adhesion-Inhibitory Activity A method for determining the activity of the CM-chitin derivatives of the present invention for inhibiting adhesion of cells to fibronectin or vitronectin will be described below.", "The competitive assays used herein have widely been employed tin the field of biochemistry and are detailed in, for instance, "Method in Enzymology", 1981, 82, pp. 803-831;", "and J. P. KOKAI Nos. Hei 1-309682 and Hei 2-174797.", "EXPERIMENTAL METHOD 1.", "Preparation of Adsorption Plate Commercially available fibroneotin (derived from human;", "purchased from Seikaqaku Kogyo K. K.) and vitronectin (derived from human;", "purchased from Funakoshi Co., Ltd.) each was diluted to 1.0 μ1/ml and 2.0 μ1/ml with PBS (NaH 2 PO 4 0.005 M+NaCl 0.07 M), 0.5 ml of the resulting diluted solution was dispensed into a plastic plate having 24 wells and incubated at 37° C. overnight to perform coating of the plate.", "Then bovine serum albumin (BSA 1%) was added followed by incubation at 37° C. for one hour for inhibiting the occurrence of nonspecific adsorption, then washing with PBS in the usual manner and sufficient drainage to give an adsorption plate.", "Adhesion-Inhibitory Test A CM-chitin derivative obtained through lyophilization was diluted with Dulbecco's Modified Eagles Medium (hereunder referred to as "DMEM") to give solutions of the CM-chitin derivative having concentrations of 0, 0.25, 0.5, 1.0 and 1.5 mg/ml respectively.", "Each of the solutions (0.25 ml) was dispensed to the plate prepared above, 0.25 ml of a suspension of endothelium cells of blood vessel (4×10 6 cells/ml) was added to the plate and incubated at 37° C. for one hour to thus cause cohesion of the cells.", "The plate was washed three times with DMEM medium to remove non-adhesive cells, then the adhered cells were peeled off with a 0.025% EDTA trypsin solution and stained with a 2% Trypan Blue solution to determine the number of the adhered cells.", "The results thus obtained are summarized in the following Tables 1 and 2.", "TABLE 1______________________________________Cell Adhesion-Inhibitory effect Against Fibronectin (cell/well) Concentration (mg/ml)Compound Added 0 [.", "].25 0.5 1.0 1.5______________________________________CM--chitin 160 171 157 165 152CM--chitin derivative-1 160 131 106 79 69CM--chitin derivative-2 160 135 99 82 75CM--chitin derivative-3 160 123 100 77 55CM--chitin derivative-4 160 141 121 80 67CM--chitin derivative-5 160 136 105 86 72CM--chitin derivative-6 160 127 107 93 66CM--chitin derivative-7 160 119 98 84 71CM--chitin derivative-8 160 130 113 80 59CM--chitin derivative 9 160 121 97 85 65CM--chitin derivative-10 160 122 110 87 73CM--chitin derivative-11 160 143 125 78 70CM--chitin derivative-12 160 125 101 89 77Sulfated CM--chitin 160 150 155 147 141CM--chitin derivative-13 160 97 77 57 33CM--chitin derivative-14 160 111 93 68 41CM--chitin derivative-15 160 105 89 65 37CM--chitin derivative-16 160 103 81 75 50CM--chitin derivative-17 160 99 84 61 35CM--chitin derivative-18 160 133 101 75 52CM--chitin derivative-19 160 127 106 79 56ArgGlyAsp 160 157 162 141 83(SEQ ID NO: 1)GlyArgGlyAspSer 160 154 140 95 80(SEQ ID NO: 8)______________________________________ TABLE 2______________________________________Cell Adhesion-Inhibitory effect Against Vitronectin (cell/well) Concentration (mg/ml)Compound Added 0 10 50 100 300______________________________________CM--chitin 249 260 243 240 255CM--chitin derivative-1 249 148 89 72 41CM--chitin derivative-2 249 137 96 78 59CM--chitin derivative-3 249 141 87 69 49CM--chitin derivative-4 249 145 90 67 45CM--chitin derivative-5 249 129 91 80 48CM--chitin derivative-6 249 133 98 71 56CM--chitin derivative-7 249 143 85 79 55CM--chitin derivative-8 249 130 95 69 47CM--chitin derivative-9 249 139 88 77 58CM--chitin derivative-10 249 136 86 71 43CM--chitin derivative-11 249 147 100 73 45CM--chitin derivative-12 249 150 101 80 59Sulfated CM--chitin 249 231 235 222 200CM--chitin derivative-13 249 103 70 47 31CM--chitin derivative-14 249 107 78 43 34CM--chitin derivative-15 249 115 69 54 38CM--chitin derivative-16 249 122 81 63 40CM--chitin derivative-17 249 114 76 48 33CM--chitin derivative-18 249 125 83 56 44CM--chitin derivative-19 249 130 92 63 39ArgGlyAsp 249 171 132 104 73(SEQ ID NO: 1)GlyArgGlyAspSer 249 157 116 87 61(SEQ lD NO: 8)______________________________________ Test Example 2: Determination of Platelet Coagulation-Inhibitory Activity The platelet coagulation-inhibitory effect of the CM-chitin derivative of the present invention was assayed, in vitro, using human plasma rich in platelet.", "The experimental method will be described below.", "EXPERIMENTAL METHOD To fresh human blood, there was added 1/9 volume of a 3.8% sodium citrate solution, the resulting mixture was centrifuged (1000 rpm;", "for 10 minutes) and the upper layer was separated as a plasma rich in platelet.", "A lyophilized CM-chitin derivative was dissolved in physiological saline to give a plurality of solutions having various concentrations ranging from 0 to 1.5 mg/ml.", "Each of the solutions (25 μ1) was added to 200 μ1 of the plasma, incubated at 37° C. for 3 minutes, then a 50 μM of ADP (adenosine diphosphate) solution or a 200 μg/ml collagen solution was added to determine the extent of coagulation in terms of transmittance determined by an aggregometer.", "The results thus obtained are listed in the following Table 3.", "Rate of Coagulation Inhibition=(1-T/T .)×100% T .", ": transmittance observed when a salt of CM-chitin derivative was not added.", "T : transmittance observed when a salt of CM-chitin derivative was added.", "TABLE 3______________________________________Platelet Coagulation-Inhibitory Action IC.", "sub[.", "].50 (μg/ml) ADP CollagenCompound Added Stimulation Stimulation______________________________________CM--chitin 96 90CM--chitin derivative-1 15 10CM--chitin derivative-2 18 10CM--chitin derivative-3 21 7CM--chitin derivative-4 29 15CM--chitin derivative-5 17 12CM--chitin derivative-6 26 11CM--chitin derivative-7 30 16CM--chitin derivative-8 24 14CM--chitin derivative-9 28 9CM--chitin derivative-10 20 13CM--chitin derivative-11 21 12CM--chitin derivative-12 30 8Sulfated CM--chitin 72 61CM--chitin derivative-13 17 7CM--chitin derivative-14 12 3CM--chitin derivative-15 15 6CM--chitin derivative-16 12 2CM--chitin derivative-17 14 5CM--chitin derivative-18 21 10CM--chitin derivative-19 19 5ArgGlyAsp 27 22(SEQ ID NO: 1)GlyArgGlyAspSer 31 18(SEQ ID NO: 8)______________________________________ __________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 9(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 3 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:ArgGlyAsp(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 6 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:ArgGlyAspArgGlyAsp15(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:ArgGlyAspArgGlyAspArgGlyAsp15(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 15 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:ArgGlyAspArgGlyAspArgGlyAspArgGlyAspArgGlyAsp151015(2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 5 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:ArgGlyAspSerGly15(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 6 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:GlyArgGlyAspSerPro15(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 4 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:ArgGlyAspSer1(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 5 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:GlyArgGlyAspSer1 5(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 4 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:GlyAspSerGly1" ]
FIELD OF THE INVENTION [0001] The present invention generally relates to ceramic micro-reactors and more particularly to a method of placing catalyst material within the ceramic micro-reactors. BACKGROUND OF THE INVENTION [0002] intentionally blank [0003] Fuel reformers have been developed for use in conjunction with various types of systems, e.g., fuel cell devices, but they are typically cumbersome and complex systems consisting of several discrete sections connected together with gas plumbing and hardware to produce hydrogen gas, and are thus not optimal for power source applications with high production volume. Recently fuel reformers have been developed utilizing ceramic monolithic structures in which the miniaturization of the reformer can be achieved. Utilizing multilayer laminated ceramic technology, ceramic components and systems are now being developed for use in microfluidic chemical processing and energy generation systems. Traditionally, multilayer ceramic structures have been used primarily for constructing “3D” circuit boards with a high degree of electronic circuitry or components embedded or integrated into the ceramic. These monolithic ceramic structures formed also have the useful properties of being relatively inert, stable to chemical reactions, and capable of tolerating high temperatures. Additionally, the ceramic materials used to form components or devices, including channeled configurations, are excellent candidates for catalyst supports and so are compatible for use in microreactor devices. An exemplary application being the generation of hydrogen for use in conjunction with fuel cell for power generation. [0004] During steam reforming, a mixture of hydrocarbon fuel and water is catalytically converted, with the application of heat, to a hydrogen enriched fuel gas for use with fuel cells. Typically, a steam reformer is endothermically operated at an elevated temperature, for example, greater than 200° C., thereby requiring a heat source to ensure the reforming reaction is maintained in its optimal operating temperature. Common means for generating these elevated temperatures has been found using conventional electrical heaters and chemical reactors (combustors) that are physically or thermally linked to the reformation reactor. [0005] Like most heterogeneous endothermic reactions, steam reformation reaction rates are kinetically limited and thus require high surface area catalysts in order to provide practical rates of hydrogen production. However, since the reaction takes place at elevated temperatures, the overall efficiency of the reformation reaction is, to a large degree, dependent on the heat lost from the reformer to the surroundings while the reaction is taking place. To minimize this heat loss, it is advantageous to construct a reformation reactor with a small volume to minimize the surface area through which heat is lost to the surroundings. So, while the nature of the steam reformation reaction requires high surface area, this must be done in a minimum amount of volume. Thus, the optimal catalyst for this class of reactions is one with very high surface areas contained internally within a very porous structure and the optimal reactor design is one that minimizes external surface area (and thus, system volume) while still maintaining a reasonably low pressure drop. Practically this means that the porous reformation catalyst should occupy as much of the internal reactor volume as possible by minimizing volume for plenums, heat transfer conduits, containment, and, if a wall-coated design, fluid channels down the reactor channel(s) Furthermore, because highly porous catalysts tend to have relatively low thermal conductivity, it is usually optimal for the steam reformation reactor design to minimize thermal transfer lengths between the heat source, such as a combustor, and the bulk of the reformation catalyst (the heat sink during operation). In practice, this often means constructing channels or chambers within the reformation reactor to be on the order of 1 mm or even smaller in at least 1 dimension. Commonly this type of design is often referred to as a “micro-reactor” even though external dimensions of the reactor may be much. [0006] Traditional filling of a ceramic-based reactor with high-surface area porous catalyst has been done after the firing (sintering) of the ceramic. Typically this is done by one of three methods: 1) catalyst pellets or particles are sucked, blown, shaken or simply dropped into the reactor (resulting in a packed-bed type reactor); 2) a catalyst paste is vacuumed or pushed into the reactor after which the reactor is heated to dry the paste and/or to burn out pore formers and/or to activate binders (resulting in packed bed or porous fixed bed type reactor); or 3) catalyst slurry is put into the reactor followed by a high velocity gas purge that blows out the slurry from the center areas of the reactor followed by heating to dry the catalyst and/or activate binders (resulting in a wall-coated type reactor). Unfortunately, all of these approaches have draw backs. First and foremost is that post-fire filling of any kind involves one or more manufacturing steps that must be done after the reactor housing is formed and thus it is difficult to have full control over how optimally the catalyst is formed and located. Second, post-fire filled reactor designs often must incorporate compromises that lower overall effectiveness of the reactor in order to accommodate the post-fire filling process, e.g., extra plenums may need to be added or extra inlet/outlet added for filling that must then be capped before operation. The post-fire slurry process has the additional drawback in that the fluid mechanics for blowing out the excess slurry to form a central fluid channel results in a smaller and smaller catalyst volume fraction as the dimensions of the reactor channel are reduced. Put another way, the thickness of the resulting catalyst layer is limited by the flow dynamics of the slurry-coating process, thus possibly limiting the reactor's catalyst volume fraction below an optimal level. [0007] Accordingly, it is desirable to provide an improved method of placing catalyst material within ceramic micro-reactors. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and [0009] FIG. 1 is a simplified top view of a first portion of a first exemplary embodiment of a micro-reactor; [0010] FIG. 2 is a simplified side view taken along line 2 - 2 of FIG. 1 ; [0011] FIG. 3 is a simplified top view of a second portion of the first exemplary embodiment; [0012] FIG. 4 is a simplified side view taken along line 4 - 2 of FIG. 3 ; [0013] FIG. 5 is a simplified side view of the first exemplary embodiment, including the first and second portion; [0014] FIG. 6 is a simplified sectional view of a fuel processor including a chemical combustion heater and a reactor for reforming methanol to hydrogen, both of which may be fabricated using the exemplary embodiments, and an integrated fuel cell stack; [0015] FIG. 7 is a schematic diagram of a fuel cell system including micro-reactors in accordance with the exemplary embodiments integrated with a fuel reformer system. DETAILED DESCRIPTION OF THE INVENTION [0016] The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention. [0017] A process is described herein that allows for integrating a high surface area supported catalyst into a ceramic micro-reactor without significantly changing the processing steps and without additional post-fire processing, thereby allowing for more optimal catalyst placement and loading, lower costs and reduced scrap. This process can form reactor channels with thick high surface area, e.g., non-sintering support, catalyst layers, e.g. greater than 50 micrometer, and high volume fraction of catalyst, e.g., greater than sixty percent within the reactor cavity. [0018] The process comprises applying high surface area catalyst layers to a green-state ceramic tape, for example, by screen printing or stencil filling techniques. After printing, the ceramic tapes (with metallization, if needed) are laminated together and then fired, thereby forming a single unit. No post-processing is required for catalyst loading. [0019] An important use of this technology is in portable power applications: specifically, fuel processors (for hydrogen generation). In the fuel processor, the endothermic reformation reaction can effectively utilize a much thicker wall-coated catalyst layer than can be utilized by corresponding heating reaction in the adjacent combustor. For portable applications, total reactor volume is critical (smaller is better) so there is a need for a mass-manufacturable technique for relatively thick wall-coated catalyst layer application that is not limited by the fluid-dynamics inherent in the traditional slurry-coated technique. [0020] The micro-reactor manufactured in accordance with the exemplary embodiments is anticipated for use in, for example, a fuel processor, an integrated reactor system that includes one or more chemical combustion heater(s), one or more reformation reactors, and possibly additional reactors (such as a water-gas-shift reactor or a preferential oxidizer or methanation reactor) all of which may be fabricated with the exemplary embodiments. The chemical combustion heater is thermally coupled to endothermic reaction zones within the fuel processor. The micro-reactor is formed utilizing multilayer ceramic technology in which thin ceramic layers are assembled then sintered to provide for miniature dimensions in which the encapsulated catalyst(s) are utilized. [0021] Referring to FIGS. 1 and 2 and in accordance with a first exemplary embodiment, a first green sheet layer 112 is cut to define opening 114 and channels 116 , and 117 and is then positioned on a second green sheet layer 118 to form a structure 100 . The first green sheet layer 112 may be formed by cutting a green ceramic sheet using a variety of methods including mechanical cutting or punching, laser or other high energy beam drilling, or simply casting or screen printing the green ceramic layer with the holes already formed. Alternatively structure 100 could be made by embossing or ablating a green ceramic layer or by injection molding or casting or some combination there of. Alternatively, structure 100 could be made by a printing or rapid prototyping technique in which a ceramic paste is printed, then cured, and then added to by printing and curing additional layers. This procedure is repeated ( FIGS. 3 and 4 ) for third green sheet layer 312 to define opening 314 and channels 316 and 317 including placement over a fourth green sheet 318 to form a structure 300 . The green sheet layers 112 , 118 , 312 , 318 may comprise any desired thickness, but typically are cut in thicknesses of 50, 125, or 250 micrometers. [0022] A catalyst material 320 is dispensed within the openings 114 and 314 , preferably by an ink jet process to a desired thickness; however, other processes such as screen printing or stencil filling techniques could be used. [0023] Referring to FIG. 4 , another green sheet layer 412 is cut to define the opening 414 . The structure 300 is flipped ( FIGS. 5 and 6 ) and laminated on one side of the green sheet layer 412 and the structure 100 is laminated on an opposed side of the green sheet layer 412 , wherein the first and third green sheet layers 112 , 312 are aligned to one another so the catalyst material 320 within openings 114 and 314 are aligned with one end of opening 414 , and channels 116 and 316 are aligned with the other end of the opening 414 . Since the catalyst material 320 was printed only within the openings 114 , 314 , a gap 502 is defined by the opening 414 not occupied by the catalyst material 118 , 318 . Channels 116 , 316 and channels 117 , 317 provide an inlet and an outlet, respectively, to the gap 502 , and therefore to the catalyst material 420 . [0024] Catalyst layers 320 formed using this process are typically between 50 and 1000 micrometers thick, however one of the significant advantages of this technique is that it allows construction of catalyst layers of any desired thickness. Furthermore, this pre-fired (green state) catalyst filling technique allows for the precise placement of the catalyst to ensure optimal reactor performance and does not require any additional inlets or outlets or flow channels that are sometimes required with post-fire catalyst filling techniques. [0025] Referring now to FIG. 7 , illustrated is a fuel processor 740 according to the present invention, including a plurality of microfluidic channels as well as a reformation reactor, and a chemical combustion heater, either of which could be fabricated according to any of the previously disclosed embodiments of the present invention. Fuel processor system 740 is comprised of a three-dimensional multilayer ceramic structure 742 . Ceramic structure 742 is formed utilizing multilayer laminate ceramic technology. Structure 742 is typically formed in component parts which are then sintered in such a way as to provide for a monolithic housing. Ceramic structure 742 has defined therein a fuel processor, generally referenced 744 . Fuel processor 744 includes a reformation-reaction zone, or fuel reformer 746 , a vaporization chamber, or vaporization zone 748 , and an integrated chemical combustion heater, 750 . It should be understood that the high surface area catalyst(s) within the fuel reformer 746 and/or the chemical combustion heater 750 could be formed according to any of the previously disclosed embodiments herein. In addition, included as a part of fuel processor 744 , is a waste heat recovery zone 752 , and a fuel cell stack 754 . [0026] Ceramic structure 742 further includes at least one fuel inlet ceramic cavity 756 in fluidic communication with fuel vaporizer 748 and a liquid fuel source. At least one fuel input inlet 758 is formed to provide for fluidic communication between a fuel source 760 , and combustion heater 750 . It should be understood that anticipated by this disclosure is a single fuel tank that is in fluidic communication with both fuel vaporizer 748 and chemical combustion heater 750 . [0027] During operation of the fuel processor 740 , fuel 757 enters fuel vaporizer 748 through a ceramic cavity 756 and is vaporized with the vaporous fuel exiting vaporizer 748 through output 762 which is in fluidic communication with fuel reformer 746 . Fuel inlet 758 provides for the input of fuel to chemical combustion heater 750 . An air inlet 764 provides for the input of air to chemical combustion heater 750 and to waste heat recovery zone 752 . Chemical combustion heater 750 allows for complete air oxidation of fuel input 758 and subsequent dissipation of heat through structure 742 and more specifically, to fuel reformer 746 and fuel vaporizer 748 . [0028] Fuel 757 entering fuel vaporizer 748 is vaporized and the resultant vaporous methanol and water enters the reaction zone, or more specifically fuel reformer, 746 where it is converted to hydrogen enriched gas. There is provided a hydrogen enriched gas outlet channel 766 from fuel reformer 746 that is in fluidic communication with an inlet to fuel cell stack 754 , and more particularly to a fuel cell anode 755 . Fuel cell anode 755 provides for depletion of hydrogen from the hydrogen enriched gas mixture. This hydrogen depleted hydrogen enriched gas mixture exits fuel cell stack 754 , and more particularly anode 755 through a fluidic communication 768 and is input to an inlet of chemical combustion heater 750 . Chemical combustion heater 750 also oxidizes portions of this gas mixture to generate heat and provides for any uncombusted materials present, such as remaining hydrogen and carbon monoxide, to undergo air oxidation to water and carbon dioxide, and these as well nitrogen from air, are then vented through an outlet 772 away from structure 742 into the atmosphere. [0029] Efficient thermal insulators 774 and 776 are positioned around fuel processor 744 , under fuel vaporizer zone 748 , and above fuel cell stack 754 to keep outer temperatures low for packaging and also to keep heat generated within the device localized to the fuel processor 744 . As illustrated in FIG. 7 , in this particular example, high temperature fuel cell stack 754 is integrated with fuel processor 744 . This particular fuel cell design allows for the operation of the fuel cell stack at a temperature ranging from 140-230° C., with a preferred temperature of 170° C. Fuel vaporizer zone 748 operates at a temperature ranging from 120-230° C., with a preferred temperature of 180° C. and fuel reformer 746 operates at a temperature ranging from 180-300° C., with a preferred temperature of 250° C. Additionally, in this particular embodiment of fuel processor system 740 , included is a top cap 778 . [0030] Finally, it is anticipated by this disclosure that although illustrated in FIG. 7 is the integration of fuel cell stack 754 with processor 744 , a design in which a fuel cell is not integrated with fuel processor 744 is additionally anticipated. Further information on a reformed hydrogen fuel system device of this type can be found in U.S. patent application Ser. No. 09/649,528, entitled “HYDROGEN GENERATOR UTILIZING CERAMIC TECHNOLOGY”, filed Aug. 28, 2000, assigned to the same assignee. When fuel cell stack 754 is integrated with fuel reformer 746 , advantage can be taken of the heat of the substrate to operate high temperature fuel cell stack 754 . For high power applications, it is convenient to design a separate fuel cell stack 754 and a fuel processor unit 744 and couple them to supply the hydrogen enriched fuel for the fuel cell. In such instances, when a fuel cell stack is not integrated with the fuel processor, and the fuel processor is designed as a stand alone device, external connection can be made to connect the stand alone fuel processor to a traditional fuel cell stack for higher power applications. [0031] Illustrated in FIG. 8 in a simplified block diagram 880 , is the fuel processor system 740 of FIG. 7 , including a multilayer ceramic structure, a fuel processor, a fuel cell stack, insulators, and fuels, similar to previously described multilayer ceramic structure 742 having a fuel processor 744 , fuel cell stack 754 , insulators 774 and 776 , and fuels 754 and 760 of device 740 . As illustrated, a fuel cartridge, generally including an optional pump mechanism 882 supplies water and methanol into a steam reformer 884 , generally similar to fuel reformer 746 of FIG. 7 and a chemical combustion heater 886 , generally similar to chemical combustion heater 750 of FIG. 7 . An air supply 888 provides for the supplying of air to heater 886 and a fuel cell stack 892 . Heater 886 is monitored by a temperature sensor, including control circuitry, 890 thereby providing for steam reformer 884 to operate at a temperature of approximately 230° C. Operation of steam reformer 884 at this temperature allows for the reforming of input fuel 882 into a reformed gas mixture, generally referred to as the hydrogen enriched gas. More particularly, in the presence of a catalyst, such as copper oxide, zinc oxide, or copper zinc oxide, the fuel solution 882 is reformed into hydrogen, carbon dioxide, and some carbon monoxide. Steam reformer 884 operates in conjunction with an optional carbon monoxide cleanup (not shown), that in the presence of a preferential oxidation catalyst and air (or 0 2 ), reforms a large percentage of the present carbon monoxide into carbon dioxide. This reformed gas mixture supplies fuel through a fuel output to fuel cell 892 , generally similar to fuel cell stack 754 of FIG. 7 . Fuel cell 892 generates electricity 894 and is illustrated in this particular example as providing energy to a DC-DC converter 896 , thereby supplying power to a cell phone 898 and/or battery 800 , for example. [0032] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
A method is provided for placing high surface area catalyst material ( 320 ) within ceramic micro-reactors. The method comprises forming a first cavity ( 114 ) in a first green sheet ( 112 ) and disposing a high surface area catalyst material ( 320 ) within the first cavity ( 114 ). The first green sheet ( 112 ) is placed adjacent to a second green sheet 118 wherein the first cavity is surrounded by the first and second green sheets. At least one input channel ( 316 ) and one output channel ( 317 ) is provided to the catalyst material before the ceramic micro-reactor is fired.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "FIELD OF THE INVENTION [0001] The present invention generally relates to ceramic micro-reactors and more particularly to a method of placing catalyst material within the ceramic micro-reactors.", "BACKGROUND OF THE INVENTION [0002] intentionally blank [0003] Fuel reformers have been developed for use in conjunction with various types of systems, e.g., fuel cell devices, but they are typically cumbersome and complex systems consisting of several discrete sections connected together with gas plumbing and hardware to produce hydrogen gas, and are thus not optimal for power source applications with high production volume.", "Recently fuel reformers have been developed utilizing ceramic monolithic structures in which the miniaturization of the reformer can be achieved.", "Utilizing multilayer laminated ceramic technology, ceramic components and systems are now being developed for use in microfluidic chemical processing and energy generation systems.", "Traditionally, multilayer ceramic structures have been used primarily for constructing “3D”", "circuit boards with a high degree of electronic circuitry or components embedded or integrated into the ceramic.", "These monolithic ceramic structures formed also have the useful properties of being relatively inert, stable to chemical reactions, and capable of tolerating high temperatures.", "Additionally, the ceramic materials used to form components or devices, including channeled configurations, are excellent candidates for catalyst supports and so are compatible for use in microreactor devices.", "An exemplary application being the generation of hydrogen for use in conjunction with fuel cell for power generation.", "[0004] During steam reforming, a mixture of hydrocarbon fuel and water is catalytically converted, with the application of heat, to a hydrogen enriched fuel gas for use with fuel cells.", "Typically, a steam reformer is endothermically operated at an elevated temperature, for example, greater than 200° C., thereby requiring a heat source to ensure the reforming reaction is maintained in its optimal operating temperature.", "Common means for generating these elevated temperatures has been found using conventional electrical heaters and chemical reactors (combustors) that are physically or thermally linked to the reformation reactor.", "[0005] Like most heterogeneous endothermic reactions, steam reformation reaction rates are kinetically limited and thus require high surface area catalysts in order to provide practical rates of hydrogen production.", "However, since the reaction takes place at elevated temperatures, the overall efficiency of the reformation reaction is, to a large degree, dependent on the heat lost from the reformer to the surroundings while the reaction is taking place.", "To minimize this heat loss, it is advantageous to construct a reformation reactor with a small volume to minimize the surface area through which heat is lost to the surroundings.", "So, while the nature of the steam reformation reaction requires high surface area, this must be done in a minimum amount of volume.", "Thus, the optimal catalyst for this class of reactions is one with very high surface areas contained internally within a very porous structure and the optimal reactor design is one that minimizes external surface area (and thus, system volume) while still maintaining a reasonably low pressure drop.", "Practically this means that the porous reformation catalyst should occupy as much of the internal reactor volume as possible by minimizing volume for plenums, heat transfer conduits, containment, and, if a wall-coated design, fluid channels down the reactor channel(s) Furthermore, because highly porous catalysts tend to have relatively low thermal conductivity, it is usually optimal for the steam reformation reactor design to minimize thermal transfer lengths between the heat source, such as a combustor, and the bulk of the reformation catalyst (the heat sink during operation).", "In practice, this often means constructing channels or chambers within the reformation reactor to be on the order of 1 mm or even smaller in at least 1 dimension.", "Commonly this type of design is often referred to as a “micro-reactor”", "even though external dimensions of the reactor may be much.", "[0006] Traditional filling of a ceramic-based reactor with high-surface area porous catalyst has been done after the firing (sintering) of the ceramic.", "Typically this is done by one of three methods: 1) catalyst pellets or particles are sucked, blown, shaken or simply dropped into the reactor (resulting in a packed-bed type reactor);", "2) a catalyst paste is vacuumed or pushed into the reactor after which the reactor is heated to dry the paste and/or to burn out pore formers and/or to activate binders (resulting in packed bed or porous fixed bed type reactor);", "or 3) catalyst slurry is put into the reactor followed by a high velocity gas purge that blows out the slurry from the center areas of the reactor followed by heating to dry the catalyst and/or activate binders (resulting in a wall-coated type reactor).", "Unfortunately, all of these approaches have draw backs.", "First and foremost is that post-fire filling of any kind involves one or more manufacturing steps that must be done after the reactor housing is formed and thus it is difficult to have full control over how optimally the catalyst is formed and located.", "Second, post-fire filled reactor designs often must incorporate compromises that lower overall effectiveness of the reactor in order to accommodate the post-fire filling process, e.g., extra plenums may need to be added or extra inlet/outlet added for filling that must then be capped before operation.", "The post-fire slurry process has the additional drawback in that the fluid mechanics for blowing out the excess slurry to form a central fluid channel results in a smaller and smaller catalyst volume fraction as the dimensions of the reactor channel are reduced.", "Put another way, the thickness of the resulting catalyst layer is limited by the flow dynamics of the slurry-coating process, thus possibly limiting the reactor's catalyst volume fraction below an optimal level.", "[0007] Accordingly, it is desirable to provide an improved method of placing catalyst material within ceramic micro-reactors.", "Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.", "BRIEF DESCRIPTION OF THE DRAWINGS [0008] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and [0009] FIG. 1 is a simplified top view of a first portion of a first exemplary embodiment of a micro-reactor;", "[0010] FIG. 2 is a simplified side view taken along line 2 - 2 of FIG. 1 ;", "[0011] FIG. 3 is a simplified top view of a second portion of the first exemplary embodiment;", "[0012] FIG. 4 is a simplified side view taken along line 4 - 2 of FIG. 3 ;", "[0013] FIG. 5 is a simplified side view of the first exemplary embodiment, including the first and second portion;", "[0014] FIG. 6 is a simplified sectional view of a fuel processor including a chemical combustion heater and a reactor for reforming methanol to hydrogen, both of which may be fabricated using the exemplary embodiments, and an integrated fuel cell stack;", "[0015] FIG. 7 is a schematic diagram of a fuel cell system including micro-reactors in accordance with the exemplary embodiments integrated with a fuel reformer system.", "DETAILED DESCRIPTION OF THE INVENTION [0016] The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention.", "Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.", "[0017] A process is described herein that allows for integrating a high surface area supported catalyst into a ceramic micro-reactor without significantly changing the processing steps and without additional post-fire processing, thereby allowing for more optimal catalyst placement and loading, lower costs and reduced scrap.", "This process can form reactor channels with thick high surface area, e.g., non-sintering support, catalyst layers, e.g. greater than 50 micrometer, and high volume fraction of catalyst, e.g., greater than sixty percent within the reactor cavity.", "[0018] The process comprises applying high surface area catalyst layers to a green-state ceramic tape, for example, by screen printing or stencil filling techniques.", "After printing, the ceramic tapes (with metallization, if needed) are laminated together and then fired, thereby forming a single unit.", "No post-processing is required for catalyst loading.", "[0019] An important use of this technology is in portable power applications: specifically, fuel processors (for hydrogen generation).", "In the fuel processor, the endothermic reformation reaction can effectively utilize a much thicker wall-coated catalyst layer than can be utilized by corresponding heating reaction in the adjacent combustor.", "For portable applications, total reactor volume is critical (smaller is better) so there is a need for a mass-manufacturable technique for relatively thick wall-coated catalyst layer application that is not limited by the fluid-dynamics inherent in the traditional slurry-coated technique.", "[0020] The micro-reactor manufactured in accordance with the exemplary embodiments is anticipated for use in, for example, a fuel processor, an integrated reactor system that includes one or more chemical combustion heater(s), one or more reformation reactors, and possibly additional reactors (such as a water-gas-shift reactor or a preferential oxidizer or methanation reactor) all of which may be fabricated with the exemplary embodiments.", "The chemical combustion heater is thermally coupled to endothermic reaction zones within the fuel processor.", "The micro-reactor is formed utilizing multilayer ceramic technology in which thin ceramic layers are assembled then sintered to provide for miniature dimensions in which the encapsulated catalyst(s) are utilized.", "[0021] Referring to FIGS. 1 and 2 and in accordance with a first exemplary embodiment, a first green sheet layer 112 is cut to define opening 114 and channels 116 , and 117 and is then positioned on a second green sheet layer 118 to form a structure 100 .", "The first green sheet layer 112 may be formed by cutting a green ceramic sheet using a variety of methods including mechanical cutting or punching, laser or other high energy beam drilling, or simply casting or screen printing the green ceramic layer with the holes already formed.", "Alternatively structure 100 could be made by embossing or ablating a green ceramic layer or by injection molding or casting or some combination there of.", "Alternatively, structure 100 could be made by a printing or rapid prototyping technique in which a ceramic paste is printed, then cured, and then added to by printing and curing additional layers.", "This procedure is repeated ( FIGS. 3 and 4 ) for third green sheet layer 312 to define opening 314 and channels 316 and 317 including placement over a fourth green sheet 318 to form a structure 300 .", "The green sheet layers 112 , 118 , 312 , 318 may comprise any desired thickness, but typically are cut in thicknesses of 50, 125, or 250 micrometers.", "[0022] A catalyst material 320 is dispensed within the openings 114 and 314 , preferably by an ink jet process to a desired thickness;", "however, other processes such as screen printing or stencil filling techniques could be used.", "[0023] Referring to FIG. 4 , another green sheet layer 412 is cut to define the opening 414 .", "The structure 300 is flipped ( FIGS. 5 and 6 ) and laminated on one side of the green sheet layer 412 and the structure 100 is laminated on an opposed side of the green sheet layer 412 , wherein the first and third green sheet layers 112 , 312 are aligned to one another so the catalyst material 320 within openings 114 and 314 are aligned with one end of opening 414 , and channels 116 and 316 are aligned with the other end of the opening 414 .", "Since the catalyst material 320 was printed only within the openings 114 , 314 , a gap 502 is defined by the opening 414 not occupied by the catalyst material 118 , 318 .", "Channels 116 , 316 and channels 117 , 317 provide an inlet and an outlet, respectively, to the gap 502 , and therefore to the catalyst material 420 .", "[0024] Catalyst layers 320 formed using this process are typically between 50 and 1000 micrometers thick, however one of the significant advantages of this technique is that it allows construction of catalyst layers of any desired thickness.", "Furthermore, this pre-fired (green state) catalyst filling technique allows for the precise placement of the catalyst to ensure optimal reactor performance and does not require any additional inlets or outlets or flow channels that are sometimes required with post-fire catalyst filling techniques.", "[0025] Referring now to FIG. 7 , illustrated is a fuel processor 740 according to the present invention, including a plurality of microfluidic channels as well as a reformation reactor, and a chemical combustion heater, either of which could be fabricated according to any of the previously disclosed embodiments of the present invention.", "Fuel processor system 740 is comprised of a three-dimensional multilayer ceramic structure 742 .", "Ceramic structure 742 is formed utilizing multilayer laminate ceramic technology.", "Structure 742 is typically formed in component parts which are then sintered in such a way as to provide for a monolithic housing.", "Ceramic structure 742 has defined therein a fuel processor, generally referenced 744 .", "Fuel processor 744 includes a reformation-reaction zone, or fuel reformer 746 , a vaporization chamber, or vaporization zone 748 , and an integrated chemical combustion heater, 750 .", "It should be understood that the high surface area catalyst(s) within the fuel reformer 746 and/or the chemical combustion heater 750 could be formed according to any of the previously disclosed embodiments herein.", "In addition, included as a part of fuel processor 744 , is a waste heat recovery zone 752 , and a fuel cell stack 754 .", "[0026] Ceramic structure 742 further includes at least one fuel inlet ceramic cavity 756 in fluidic communication with fuel vaporizer 748 and a liquid fuel source.", "At least one fuel input inlet 758 is formed to provide for fluidic communication between a fuel source 760 , and combustion heater 750 .", "It should be understood that anticipated by this disclosure is a single fuel tank that is in fluidic communication with both fuel vaporizer 748 and chemical combustion heater 750 .", "[0027] During operation of the fuel processor 740 , fuel 757 enters fuel vaporizer 748 through a ceramic cavity 756 and is vaporized with the vaporous fuel exiting vaporizer 748 through output 762 which is in fluidic communication with fuel reformer 746 .", "Fuel inlet 758 provides for the input of fuel to chemical combustion heater 750 .", "An air inlet 764 provides for the input of air to chemical combustion heater 750 and to waste heat recovery zone 752 .", "Chemical combustion heater 750 allows for complete air oxidation of fuel input 758 and subsequent dissipation of heat through structure 742 and more specifically, to fuel reformer 746 and fuel vaporizer 748 .", "[0028] Fuel 757 entering fuel vaporizer 748 is vaporized and the resultant vaporous methanol and water enters the reaction zone, or more specifically fuel reformer, 746 where it is converted to hydrogen enriched gas.", "There is provided a hydrogen enriched gas outlet channel 766 from fuel reformer 746 that is in fluidic communication with an inlet to fuel cell stack 754 , and more particularly to a fuel cell anode 755 .", "Fuel cell anode 755 provides for depletion of hydrogen from the hydrogen enriched gas mixture.", "This hydrogen depleted hydrogen enriched gas mixture exits fuel cell stack 754 , and more particularly anode 755 through a fluidic communication 768 and is input to an inlet of chemical combustion heater 750 .", "Chemical combustion heater 750 also oxidizes portions of this gas mixture to generate heat and provides for any uncombusted materials present, such as remaining hydrogen and carbon monoxide, to undergo air oxidation to water and carbon dioxide, and these as well nitrogen from air, are then vented through an outlet 772 away from structure 742 into the atmosphere.", "[0029] Efficient thermal insulators 774 and 776 are positioned around fuel processor 744 , under fuel vaporizer zone 748 , and above fuel cell stack 754 to keep outer temperatures low for packaging and also to keep heat generated within the device localized to the fuel processor 744 .", "As illustrated in FIG. 7 , in this particular example, high temperature fuel cell stack 754 is integrated with fuel processor 744 .", "This particular fuel cell design allows for the operation of the fuel cell stack at a temperature ranging from 140-230° C., with a preferred temperature of 170° C. Fuel vaporizer zone 748 operates at a temperature ranging from 120-230° C., with a preferred temperature of 180° C. and fuel reformer 746 operates at a temperature ranging from 180-300° C., with a preferred temperature of 250° C. Additionally, in this particular embodiment of fuel processor system 740 , included is a top cap 778 .", "[0030] Finally, it is anticipated by this disclosure that although illustrated in FIG. 7 is the integration of fuel cell stack 754 with processor 744 , a design in which a fuel cell is not integrated with fuel processor 744 is additionally anticipated.", "Further information on a reformed hydrogen fuel system device of this type can be found in U.S. patent application Ser.", "No. 09/649,528, entitled “HYDROGEN GENERATOR UTILIZING CERAMIC TECHNOLOGY”, filed Aug. 28, 2000, assigned to the same assignee.", "When fuel cell stack 754 is integrated with fuel reformer 746 , advantage can be taken of the heat of the substrate to operate high temperature fuel cell stack 754 .", "For high power applications, it is convenient to design a separate fuel cell stack 754 and a fuel processor unit 744 and couple them to supply the hydrogen enriched fuel for the fuel cell.", "In such instances, when a fuel cell stack is not integrated with the fuel processor, and the fuel processor is designed as a stand alone device, external connection can be made to connect the stand alone fuel processor to a traditional fuel cell stack for higher power applications.", "[0031] Illustrated in FIG. 8 in a simplified block diagram 880 , is the fuel processor system 740 of FIG. 7 , including a multilayer ceramic structure, a fuel processor, a fuel cell stack, insulators, and fuels, similar to previously described multilayer ceramic structure 742 having a fuel processor 744 , fuel cell stack 754 , insulators 774 and 776 , and fuels 754 and 760 of device 740 .", "As illustrated, a fuel cartridge, generally including an optional pump mechanism 882 supplies water and methanol into a steam reformer 884 , generally similar to fuel reformer 746 of FIG. 7 and a chemical combustion heater 886 , generally similar to chemical combustion heater 750 of FIG. 7 .", "An air supply 888 provides for the supplying of air to heater 886 and a fuel cell stack 892 .", "Heater 886 is monitored by a temperature sensor, including control circuitry, 890 thereby providing for steam reformer 884 to operate at a temperature of approximately 230° C. Operation of steam reformer 884 at this temperature allows for the reforming of input fuel 882 into a reformed gas mixture, generally referred to as the hydrogen enriched gas.", "More particularly, in the presence of a catalyst, such as copper oxide, zinc oxide, or copper zinc oxide, the fuel solution 882 is reformed into hydrogen, carbon dioxide, and some carbon monoxide.", "Steam reformer 884 operates in conjunction with an optional carbon monoxide cleanup (not shown), that in the presence of a preferential oxidation catalyst and air (or 0 2 ), reforms a large percentage of the present carbon monoxide into carbon dioxide.", "This reformed gas mixture supplies fuel through a fuel output to fuel cell 892 , generally similar to fuel cell stack 754 of FIG. 7 .", "Fuel cell 892 generates electricity 894 and is illustrated in this particular example as providing energy to a DC-DC converter 896 , thereby supplying power to a cell phone 898 and/or battery 800 , for example.", "[0032] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist.", "It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way.", "Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims." ]
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/334,474, filed on Nov. 16, 2001. FIELD OF THE INVENTION [0002] The present invention pertains to amusement slides, particularly water slides. BACKGROUND OF THE INVENTION [0003] In known water slides, a user typically coasts along a slippery surface from a higher elevation to a lower elevation, either in a straight line path or a path that includes curves. A water slide may take the form of a flume in which a large volume of water is introduced at the entry for lubricating the surface of the slide and for assisting in moving the user along the flume, and/or one or more sections that are misted with water to maintain the slippery characteristic of the slide surface. Sometimes the user will sit or lie on a mat or ride in a vehicle designed to coast along a predefined route. Water slides typically terminate at an exit pool. SUMMARY OF THE INVENTION [0004] The present invention provides an amusement device in the nature of a slide having a long predetermined path along its length from a high elevation at a first end portion thereof to a lower elevation at a second end portion thereof. The slide has a rider entrance between the first and second end portions and at an elevation below the high elevation. A rider is introduced through the entrance in a direction toward the first end portion such that the rider slides upward toward the first end portion while decelerating, followed by sliding travel of the rider along the predetermined path from the first end portion to the second end portion. DESCRIPTION OF THE DRAWINGS [0005] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: [0006] [0006]FIG. 1 is a side elevation of an undulating amusement slide in accordance with the present invention; [0007] [0007]FIG. 2 is a top plan of the slide of FIG. 1; [0008] [0008]FIG. 3 is an enlarged, somewhat diagrammatic bottom perspective of a portion of the slide of FIG. 1, with parts shown in exploded relationship, and FIG. 4 is a top perspective of such portion with parts assembled; [0009] [0009]FIG. 5 is a somewhat diagrammatic, enlarged transverse section taken along line 5 - 5 of FIG. 2; and [0010] [0010]FIG. 6 is a top plan of a modified slide in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0011] With reference to FIG. 1 and FIG. 2, an embodiment of a slide 10 in accordance with the present invention includes an entry platform 12 at a high elevation, reachable by several flights of stairs 14 . Platform 10 includes a recessed entry box 16 into which water is continuously pumped. The entry box is configured so that water overflows into a downhill “inlet section” or segment 18 which, for much of its length, can function as a flume. A user may slide in the flume or ride in a buoyant and resilient vehicle, such a donut-shaped, inflated inner tube, or a double “figure 8” tube having two cavities for two riders. Upright sidewalls define the long, narrow path of the inlet segment. [0012] The upper portion 20 of the inlet segment 18 is curved gradually downward to a more steeply inclined central section 22 for acceleration of the rider or riders. The central section 22 can be substantially linear, leading to the lower portion 24 which is curved oppositely from the upper portion 20 to the bottom end 26 . The bottom end 26 can be approximately horizontal. In the case of an inlet segment 18 having an upper portion 20 formed as a flume and carrying a substantial volume of water introduced at the entry box 16 , roller drains 28 can be provided at approximately the center and toward the of the inlet section 18 . Drains of this type are illustrated in FIG. 3 and FIG. 4. These views also illustrate the general contour of the narrow inlet segment 18 . The roller drain sections include an essentially flat, horizontal bottom 21 along which the rider's vehicle coasts, and curved sidewalls 23 for retaining the rider or vehicle in the flume. Rollers 29 extend transversely across the bottom and are spaced apart slightly so that water in the trough will pass between the rollers. [0013] Returning to FIGS. 1 and 2, by the time the rider reaches the bottom 26 of the inlet section 18 , he or she will be traveling at a high rate of speed along the slippery bottom surface of the flume, although by this time the slippery characteristics of the inlet section may be maintained by misting since essentially all or at least most of the water introduced from the entry box will have passed through the roller drains 28 . At this point, i.e., the bottom or outlet 26 of the inlet segment (which also is the rider entrance for the next segment), the rider passes to an upwardly curved section 30 of a separate slide portion or segment 32 which also can be referred to as the “exit slide.” In the illustrated embodiment, the exit slide 32 is substantially wider than the inlet segment 18 , allowing for unpredictable twists and turns of the rider or vehicle after it is propelled out of the inlet segment 18 . The inlet segment 18 preferably enters the exit slide 32 at an angle so that the rider is propelled toward the center of the exit slide. [0014] Upon entering the exit slide, the rider and vehicle decelerate from a high rate of speed as they transit upward along the upper curved section 30 . Ultimately, the rider will travel back down along the upper curved section, past the bottom 26 of the inlet section 18 . Along the entire exit slide 32 , the slippery characteristics of the slide can be maintained by misting, such as by apparatus of the type shown in FIG. 5. Nozzles 34 can be spaced along the length of the slide, with some nozzles pointed inward and others more outward to lubricate the entire flat bottom surface 35 of the slide. Sidewalls 36 are provided to retain the rider and vehicle in the exit slide. [0015] Referring to FIGS. 1 and 2, from a location close to the top of the upper curved section 30 , the rider accelerates downward to a generally horizontal bottom section 38 , then up and over a hill section 40 which may be designed to follow an approximate free fall parabolic path or which may result in the rider becoming airborne for a short distance after passing the top 42 of the hill. The rider then coasts along an exit section 46 which is inclined downward at a small acute angle, such as approximately 5 degrees, for maintaining a fast but safe rate of speed or slight deceleration until the rider exits the slide into an exit pool 48 . The exit slide defines a separate, long, predetermined path along its length from the higher elevation toward the top of section 30 to which a rider is propelled, to the lower elevation at the exit end. [0016] While an embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, the invention has been described with reference to a flume inlet section 18 for introducing the rider into the main slide 32 . This also could be achieved by a misted inlet slide, in which case the drains 28 could be deleted. In another embodiment, the rider could be propelled onto the main slide 32 in a different manner. For example, with reference to FIG. 6, a mechanical acceleration component 50 could be provided to introduce the rider onto the main slide at approximately the same location and speed. The mechanical acceleration apparatus could include one or more conveyors or spring-loaded or elastic-cord members to propel one or more riders onto the main slide 32 for travel upward along the curved section 30 , then downward and over the hill section 40 to an exit section 46 . Similarly, the exit slide could be provided without a hill section 40 , or with more than one hill, and/or with curves.
A rider slides down an inlet slide to a low entrance opening of a separate exit slide. The exit slide has an inclined portion along which the rider decelerates from the entrance as he or she moves upward, followed by downward travel along a predetermined path of the separate exit slide from a high elevation, past the entrance, to a low elevation.
Identify and summarize the most critical features from the given passage.
[ "CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/334,474, filed on Nov. 16, 2001.", "FIELD OF THE INVENTION [0002] The present invention pertains to amusement slides, particularly water slides.", "BACKGROUND OF THE INVENTION [0003] In known water slides, a user typically coasts along a slippery surface from a higher elevation to a lower elevation, either in a straight line path or a path that includes curves.", "A water slide may take the form of a flume in which a large volume of water is introduced at the entry for lubricating the surface of the slide and for assisting in moving the user along the flume, and/or one or more sections that are misted with water to maintain the slippery characteristic of the slide surface.", "Sometimes the user will sit or lie on a mat or ride in a vehicle designed to coast along a predefined route.", "Water slides typically terminate at an exit pool.", "SUMMARY OF THE INVENTION [0004] The present invention provides an amusement device in the nature of a slide having a long predetermined path along its length from a high elevation at a first end portion thereof to a lower elevation at a second end portion thereof.", "The slide has a rider entrance between the first and second end portions and at an elevation below the high elevation.", "A rider is introduced through the entrance in a direction toward the first end portion such that the rider slides upward toward the first end portion while decelerating, followed by sliding travel of the rider along the predetermined path from the first end portion to the second end portion.", "DESCRIPTION OF THE DRAWINGS [0005] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: [0006] [0006 ]FIG. 1 is a side elevation of an undulating amusement slide in accordance with the present invention;", "[0007] [0007 ]FIG. 2 is a top plan of the slide of FIG. 1;", "[0008] [0008 ]FIG. 3 is an enlarged, somewhat diagrammatic bottom perspective of a portion of the slide of FIG. 1, with parts shown in exploded relationship, and FIG. 4 is a top perspective of such portion with parts assembled;", "[0009] [0009 ]FIG. 5 is a somewhat diagrammatic, enlarged transverse section taken along line 5 - 5 of FIG. 2;", "and [0010] [0010 ]FIG. 6 is a top plan of a modified slide in accordance with the present invention.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0011] With reference to FIG. 1 and FIG. 2, an embodiment of a slide 10 in accordance with the present invention includes an entry platform 12 at a high elevation, reachable by several flights of stairs 14 .", "Platform 10 includes a recessed entry box 16 into which water is continuously pumped.", "The entry box is configured so that water overflows into a downhill “inlet section”", "or segment 18 which, for much of its length, can function as a flume.", "A user may slide in the flume or ride in a buoyant and resilient vehicle, such a donut-shaped, inflated inner tube, or a double “figure 8”", "tube having two cavities for two riders.", "Upright sidewalls define the long, narrow path of the inlet segment.", "[0012] The upper portion 20 of the inlet segment 18 is curved gradually downward to a more steeply inclined central section 22 for acceleration of the rider or riders.", "The central section 22 can be substantially linear, leading to the lower portion 24 which is curved oppositely from the upper portion 20 to the bottom end 26 .", "The bottom end 26 can be approximately horizontal.", "In the case of an inlet segment 18 having an upper portion 20 formed as a flume and carrying a substantial volume of water introduced at the entry box 16 , roller drains 28 can be provided at approximately the center and toward the of the inlet section 18 .", "Drains of this type are illustrated in FIG. 3 and FIG. 4. These views also illustrate the general contour of the narrow inlet segment 18 .", "The roller drain sections include an essentially flat, horizontal bottom 21 along which the rider's vehicle coasts, and curved sidewalls 23 for retaining the rider or vehicle in the flume.", "Rollers 29 extend transversely across the bottom and are spaced apart slightly so that water in the trough will pass between the rollers.", "[0013] Returning to FIGS. 1 and 2, by the time the rider reaches the bottom 26 of the inlet section 18 , he or she will be traveling at a high rate of speed along the slippery bottom surface of the flume, although by this time the slippery characteristics of the inlet section may be maintained by misting since essentially all or at least most of the water introduced from the entry box will have passed through the roller drains 28 .", "At this point, i.e., the bottom or outlet 26 of the inlet segment (which also is the rider entrance for the next segment), the rider passes to an upwardly curved section 30 of a separate slide portion or segment 32 which also can be referred to as the “exit slide.”", "In the illustrated embodiment, the exit slide 32 is substantially wider than the inlet segment 18 , allowing for unpredictable twists and turns of the rider or vehicle after it is propelled out of the inlet segment 18 .", "The inlet segment 18 preferably enters the exit slide 32 at an angle so that the rider is propelled toward the center of the exit slide.", "[0014] Upon entering the exit slide, the rider and vehicle decelerate from a high rate of speed as they transit upward along the upper curved section 30 .", "Ultimately, the rider will travel back down along the upper curved section, past the bottom 26 of the inlet section 18 .", "Along the entire exit slide 32 , the slippery characteristics of the slide can be maintained by misting, such as by apparatus of the type shown in FIG. 5. Nozzles 34 can be spaced along the length of the slide, with some nozzles pointed inward and others more outward to lubricate the entire flat bottom surface 35 of the slide.", "Sidewalls 36 are provided to retain the rider and vehicle in the exit slide.", "[0015] Referring to FIGS. 1 and 2, from a location close to the top of the upper curved section 30 , the rider accelerates downward to a generally horizontal bottom section 38 , then up and over a hill section 40 which may be designed to follow an approximate free fall parabolic path or which may result in the rider becoming airborne for a short distance after passing the top 42 of the hill.", "The rider then coasts along an exit section 46 which is inclined downward at a small acute angle, such as approximately 5 degrees, for maintaining a fast but safe rate of speed or slight deceleration until the rider exits the slide into an exit pool 48 .", "The exit slide defines a separate, long, predetermined path along its length from the higher elevation toward the top of section 30 to which a rider is propelled, to the lower elevation at the exit end.", "[0016] While an embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.", "For example, the invention has been described with reference to a flume inlet section 18 for introducing the rider into the main slide 32 .", "This also could be achieved by a misted inlet slide, in which case the drains 28 could be deleted.", "In another embodiment, the rider could be propelled onto the main slide 32 in a different manner.", "For example, with reference to FIG. 6, a mechanical acceleration component 50 could be provided to introduce the rider onto the main slide at approximately the same location and speed.", "The mechanical acceleration apparatus could include one or more conveyors or spring-loaded or elastic-cord members to propel one or more riders onto the main slide 32 for travel upward along the curved section 30 , then downward and over the hill section 40 to an exit section 46 .", "Similarly, the exit slide could be provided without a hill section 40 , or with more than one hill, and/or with curves." ]
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit of Taiwan application serial no. 98132452, filed on Sep. 25, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The invention relates to a touch panel, and more particularly, to a touching point detection method thereof. [0004] 2. Description of Related Art [0005] With the advancement in electronic techniques, consumers' demands on quality and functions of electronic products have increased as well. In order to attract the consumers by making the operation of these electronic products more convenient, various humanized human-machine interfaces have been proposed. [0006] In the various human-machine interfaces, the most common interface is the so-called touch panel. The touch panel is a device capable of receiving input signals such as contacts (i.e. fingers, stylus, and etc.) and the like. When the user's finger touches the touch panel, the touch sensor on the panel transmits back an electrical signal generated correspondingly. The touch signal is then utilized to determine the corresponding actions performed by the user on the touch panel. [0007] In a conventional capacitive touch panel, the number and the coordinates of the touching point are directly detected according to the capacitive varying value transmitted by the touch units disposed thereon. However, in the practical application, noises always cause various affects. Thus, in a conventional touch panel, many complicated circuit devices have to be disposed to reduce the noise in the environment, thereby increasing the manufacturing cost. Moreover, the forces the users exerted when touching on the touch panel are not the same, so the differentiation generated by different users is not often considered. Hence, conventional touch panels usually result in many inaccuracies when detecting the number of the touching point and the coordinates thereof. SUMMARY OF THE INVENTION [0008] The invention is directed to a touch panel configured to detect a number of a touching point accurately and positioning a location of the touching point. [0009] The invention is further directed to a method of detecting a touching point on a touch panel, and the method is configured to accurately detect a number of the touching point and positioning a location of the touching point. [0010] The invention provides a touch panel including at least one touching detection column and a touching point detection module. The touching detection column includes N first touching detection units, where N is a positive integer. Each first touching detection unit transmits a first capacitance varying value according to an area covered by a touching point. The touching point detection module is coupled to the first touching detection units to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units. Consequently, a first capacitance varying order distribution is obtained. The touching point detection module obtains a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution. [0011] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by an (i+1) th first touching detection unit from the first capacitance varying value transmitted by an i th first touching detection unit according to the arrangement order of the first touching detection units to perform the subtractive operation. Moreover, the touching point detection module subtracts the first capacitance varying value transmitted by an (i−1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit to perform the subtractive operation, where i is an even number. [0012] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by the (i+1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit according to the arrangement order of the first touching detection units to perform the subtractive operation. Moreover, the touching point detection module subtracts the first capacitance varying value transmitted by an (i−1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit to perform the subtractive operation, where i is an odd number. [0013] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by the (i+1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit according to the arrangement order of the first touching detection units to operate the subtractive operation, where i is a positive integer. [0014] According to an embodiment of the invention, the touching point detection module obtains a plurality of symbol results and a plurality of absolute differences according to the subtractive operation. [0015] According to an embodiment of the invention, the touching point detection module further determines whether each of the absolute differences and each corresponding symbol result are recorded to the first capacitance varying order distribution according to a comparison result of each of the absolute differences and a threshold. [0016] According to an embodiment of the invention, the touching point detection module obtains the number of the first touching point according to the symbol results in the first capacitance varying order distribution. [0017] According to an embodiment of the invention, the touching point detection module obtains the coordinates of the first touching point according to the consecutive absolute differences in the first capacitance varying order distribution. [0018] According to an embodiment of the invention, the touch panel further includes at least one touching detection row. The touching detection row is coupled to the touching point detection module. The touching detection row includes M second touching detection units. Each second touching detection unit transmits a second capacitance varying value according to an area covered by the touching point, wherein M is a positive integer. [0019] According to an embodiment of the invention, the touching point detection module operates the subtractive operation on the second capacitance varying values transmitted by two adjacent second touching detection units according to an arrangement order of the second touching detection units to obtain a second capacitance varying order distribution. The touching point detection module obtains a number of the second touching point on the touch panel and coordinates of the second touching point according to the second capacitance varying order distribution. [0020] According to an embodiment of the invention, the touching point detection module further determines whether each of the absolute differences and each corresponding symbol result are recorded to the second capacitance varying order distribution according to a comparison result of each of the absolute differences and a threshold. [0021] According to an embodiment of the invention, the touching point detection module obtains the number of the second touching point according to a number of times consecutively showing the symbol results in the second capacitance varying order distribution. [0022] According to an embodiment of the invention, the touching point detection module obtains the coordinates of the second touching point according to the consecutive absolute differences in the second capacitance varying order distribution. [0023] The invention is further directed to a method of detecting a touching point on a touch panel. The method includes the following. Firstly, a plurality of first touching detection units is provided and therefore arranged into at least one touching detection column. A touching point detection module is provided to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units. As a consequence, a first capacitance varying order distribution is obtained. Finally, the touching point detection module is provided to obtain a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution. [0024] In light of the foregoing, the subtractive operation is operated by using the capacitance varying values transmitted by adjacent touching detection units in the same touching detection column or the same touching detection row. In addition, the number of the touching point and the coordinates of the touching point are determined according to the distribution of the symbol results obtained from the subtractive operation. Furthermore, the absolute differences obtained from the subtractive operation are applied to compensate the calculated coordinates of the touching point, so that the coordinates of the touching point can be marked more accurately. [0025] In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with drawings are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS [0026] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. [0027] FIG. 1A is a schematic view illustrating a touch panel 100 according to an embodiment of the invention. [0028] FIG. 1B illustrates another exemplary embodiment of the touch panel 100 . [0029] FIG. 2 is a schematic view illustrating a touch panel 200 according to another embodiment of the invention. [0030] FIG. 3 is a flowchart illustrating a method of detecting a touching point on a touch panel according to an embodiment of the invention. DESCRIPTION OF EMBODIMENTS [0031] Referring to FIG. 1A , FIG. 1A is a schematic view illustrating a touch panel 100 according to an embodiment of the invention. The touch panel 100 includes a touching detection column 110 having a plurality of touching detection units 111 ˜ 115 and a touching point detection module 120 . Each of the touching detection units transmits a corresponding capacitance varying value according to an area covered by a touching point. [0032] The touching point detection module 120 is coupled to the touching detection column 110 . When the touching point detection module 120 detects the touching point on the touching detection column 110 , the touching point detection module 120 operates a subtractive operation on capacitance varying values transmitted by two adjacent touching detection units according to an arrangement order of the touching detection units 111 ˜ 115 . In other words, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 111 , 112 according to an order from left to right as shown in FIG. 1 . Afterwards, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 114 , 115 . Accordingly, the detection is performed until the subtractive operation has been operated on the capacitance varying values transmitted by two adjacent touching detection units within all of the touching detection units 111 ˜ 115 . [0033] Obviously, the touching point detection module 120 also operates the subtractive operation in another order from right to left as shown in FIG. 1 . That is, the subtractive operation is first operated on the capacitance varying values transmitted by the touching detection units 115 , 114 . Afterwards, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 114 , 113 . Here, when the touching point detection module 120 detects the touching point, the order of executing the subtractive operation is not limited. [0034] Moreover, in the so-called subtractive operation, the touching point detection module 120 performs subtraction on the capacitance varying values transmitted by two adjacent touching detection units. In other words, the touching point detection module 120 subtracts the capacitance varying value transmitted by the touching detection unit 112 from the capacitance varying value transmitted by the touching detection unit 111 . Next, the touching point detection module 120 subtracts the capacitance varying value transmitted form the touching detection unit 112 from the capacitance varying value transmitted by the touching detection unit 113 . Accordingly, the touching point detection module 120 sequentially executes multiple subtractive operations aforementioned. Moreover, each subtractive operation result is recorded according to an order of executions to obtain a capacitance varying order distribution. [0035] The touching point detection module 120 can also subtracts the capacitance varying value transmitted by the touching detection unit 111 from the capacitance varying value transmitted by the touching detection unit 112 . Afterwards, the touching point detection module 120 subtracts the capacitance varying value transmitted by the touching detection unit 113 from the capacitance varying value transmitted by the touching detection unit 112 . Accordingly, multiple subtractive operations are executed in sequence to obtain the capacitance varying order distribution. [0036] That is, the touching point detection module 120 sets the capacitance varying values that are transmitted by the even number touching detection units 112 , 114 in the touching detection column 110 to be the subtrahend in the subtractive operation. In addition, the capacitance varying values that are transmitted by the odd number touching detection units 111 , 113 , 115 in the touching detection column 110 are set to be the minuend in the subtraction. Alternatively, the capacitance varying values that are transmitted by the odd number touching detection units 111 , 113 , 115 in the touching detection column 110 are set to be the subtrahend in the subtractive operation. Additionally, the capacitance varying values that are transmitted by the even number touching detection units 112 , 114 in the touching detection column 110 are set to be the minuend in the subtraction. [0037] It should be noted that a symbol result and an absolute difference are produced in every subtractive operation aforementioned. When the capacitance varying value transmitted by the touching detection unit set to be the minuend (i.e. the touching detection unit 111 ) is larger than the capacitance varying value transmitted by the touching detection unit set to be the subtrahend (i.e. the touching detection unit 112 ), the symbol result generated from the subtractive operation is “+”. On the contrary, in the case mentioned above, when the capacitance varying value transmitted the touching detection unit 111 is smaller than the capacitance varying value transmitted by the touching detection unit 112 , which is set to be the subtrahend, the symbol result generated from the subtractive operation is “−”. The absolute difference is an absolute value of the difference between the capacitance varying values of the touching detection units 111 , 112 . Further, when operating the subtractive operation, the touching point detection module 120 compares the calculated absolute difference with a predetermined threshold. When the absolute difference is smaller than the threshold, the touching point detection module 120 forsakes the result generated from this subtractive operation. When the absolute difference is larger than or equal to the threshold, the touching point detection module 120 records the symbol result and the absolute difference generated from the subtractive operation into the capacitance varying order distribution. The threshold is set to prevent the capacitance varying value transmitted by the touching detection unit from being affected by environmental noise, which leads to an erroneous touching point. For example, in the illustration of FIG. 1 , the range of a touching point 160 includes a small portion of touching detection unit 112 and most of the touching detection unit 113 . The touching detection units 114 , 115 are not covered at all. Theoretically, the capacitance varying values transmitted by the touching detection units 114 , 115 should both be 0. However, without setting the threshold, when the touching detection unit 115 generates a capacitance varying value larger than 0 due to the interference of environmental noise, the symbol result and the absolute difference generated from the subtractive operation of the touching detection units 114 , 115 are not 0, thereby affecting the result of the detection. [0038] The threshold can be set in accordance to actual usage and environment. When the detection of the touch panel is expected to be more sensitive, a lower threshold can be set in an environment with less interference. Oppositely, when the detection of the touch panel is expected to be more constant, a higher threshold can be set in an environment with more interference. An exemplary example is shown in the following to illustrate the operation of the touch panel 100 in the present embodiment. Referring to FIG. 1 , the range of the touching point 160 includes a small portion of the touching detection unit 112 and most of the touching detection unit 113 . Additionally, the touching detecting units 111 , 113 , 115 are set to minuend and the touching detecting units 112 , 114 are set to be subtrahend. The touching point detection module 120 operates the subtractive operation from right to left in sequence. Firstly, the touching point detection module 120 operates the subtractive operation on the touching detection units 111 , 112 , and a symbol result obtained is “−”. Thereafter, the touching point detection module 120 operates the subtractive operation on the touching detection units 112 , 113 . Since an area covered by the touching detection unit 113 is larger than an area covered by the touching detection unit 112 , the symbol result here is “+”. Next, the touching point detection module 120 operates the subtractive operation on the touching detection units 113 , 114 and consequently obtains a symbol result of “+”. Since the touching detection units 114 , 115 are not covered, the capacitance varying values thereof do not exceed the threshold. Thus, the symbol result obtained from the subtractive operation on the touching detection units 114 , 115 is 0. [0039] It should be noted that when a bit is used to record the symbol result of the subtractive operation of two adjacent touching detection units, “1” is utilized to represent the symbol result “+” and “0” is used to represent the symbol result “−”. Alternatively, “1” can be utilized to represent the symbol result “−” while “0” is used to represent the symbol result “+”. However, since a bit can not generate a third level to represent the symbol result “0”, “1” or “0” can be set to permanently represent the symbol result “0”. [0040] Therefore, in the present embodiment, the capacitance varying order distribution has symbol results of “−” “+” “+” “0”. Here, “0” means the symbol result of this subtractive operation is not recorded into the capacitance varying order distribution. From the capacitance varying order distribution, it is observed that a continuous symbol result (“−” “+” “+”) is present under the condition of this embodiment. Accordingly, the touching point detection module 120 determines the touch panel 100 of the present embodiment to include a touching point. [0041] From the illustrations aforementioned, when a plurality of touching points touches a touching apparatus 100 , the capacitance varying order distribution then shows changes in the continuous symbol results (“+” or “−”) that are equivalent to the numbers of touching points. The touching point detection module 120 can also obtain the numbers of more than one touching points according to the capacitance varying order distribution. [0042] Obviously, the touching detection units covered by the touching point 160 are also obtained by utilizing the capacitance varying order distribution. In addition, with the principle that the larger the area of the touching detection units covered by the touching point 160 , the larger the transmitted capacitance varying value is, a plurality of absolute differences in the capacitance varying order distribution is used to calculate the accurate coordinates of the touching point 160 . [0043] Referring to FIG. 1B , FIG. 1B illustrates another exemplary embodiment of the touch panel 100 . In the illustration in FIG. 1B , the subtractive operations of the capacitance varying values transmitted by two adjacent touching detection units are different from those illustrated in FIG. 1A . When the subtractive operation is operated on the touching detection units 112 , 113 in FIG. 1B , the capacitance varying value of the touching detection unit 113 is subtracted from the capacitance varying value of the touching detection unit 112 . That is, in the present embodiment, the capacitance varying value of the latter touching detection unit of two adjacent touching detection units is subtracted from the capacitance varying value of the former touching detection unit to complete the subtractive operation. [0044] From the illustrations in FIG. 1A and FIG. 1B , the subtrahend and the minuend of two adjacent touching detection units in the subtractive operation are not limited in the invention. The subtractive operations operated on the capacitance varying values transmitted by two adjacent touching detection units all belong within the protection range of the invention. [0045] Referring to FIG. 2 , FIG. 2 is a schematic view illustrating a touch panel 200 according to another embodiment of the invention. The touch panel 200 includes a plurality of touching detection columns disposed along axes 211 , 212 , 213 , 214 , and 215 , and a plurality of touching detection rows disposed along axes 221 , 222 , 223 , 224 , and 225 . The exemplary embodiments of the touching detection column and the touching detection column 110 illustrated in FIG. 1 are the same. The touching detection row and the touching detection column are disposed in perpendicular to each other. Take the touching detection row disposed along the axis 221 as an example, the touching detection row includes touching detection units 2211 , 2212 , 2213 , and 2214 . [0046] A touching point detection module 230 is coupled to all of the touching detection rows and touching detection columns. Here, the touching point detection module 230 operates the subtractive operation on each adjacent touching detection unit of each touching detection row to obtain the corresponding capacitance varying order distribution. Next, the touching point detection module 230 operates the subtractive operation on each adjacent touching detection unit of each touching detection column to obtain the corresponding capacitance varying order distribution. On the other hand, the touching point detection module 230 can first operate the subtractive operation on each adjacent touching detection unit of each touching detection column to obtain the corresponding capacitance varying order distribution, and then operate the subtractive operation on each adjacent touching detection unit of each touching detection row to obtain the corresponding capacitance varying order distribution. The operating method of the subtractive operation on the touching detection row is the same as the exemplary embodiment of the subtractive operation on the touching detection column, and is thus not repeated herein. [0047] That is, since the touching detection row and the touching detecting column both have touching detection units that are independent to one another, the touch panel 200 can obtain coordinates of the touching point in the perpendicular axis and horizontal axis to attain the ability of two-dimensional positioning. [0048] It should be noted that in the present embodiment, the touching point detection module 230 includes a plurality of difference calculators 231 ˜ 238 for respectively calculating differences in capacitance varying values of adjacent touching detection units in different touching detection rows and touching detection columns. Since the touching point detection module 230 only calculates the difference in capacitance varying values of two adjacent touching detection units at a time, only one difference calculator may be used. Moreover, the subtractive operation is performed by selecting the capacitance varying values of adjacent touching detection units to be calculated during a plurality of different timing periods through a multiplexer. [0049] Referring to FIG. 3 , FIG. 3 is a flowchart illustrating a method of detecting a touching point on a touch panel according to an embodiment of the invention. The method includes the following. Firstly, a plurality of first touching detection units is provided and arranged into at least one touching detection column (S 310 ). Next, a touching point detection module is provided to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units. As a consequence, a first capacitance varying order distribution is obtained (S 320 ). Finally, the touching point detection module is provided to obtain a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution (S 330 ). The operation details of the method of detecting the touching point of the touch panel in the embodiment of the invention are illustrated in the different embodiments illustrated in FIGS. 1A , 1 B, and 2 , and thus are not repeated hereinafter. [0050] In summary, in the invention, the subtractive operation is sequentially operated on the capacitance varying values of two adjacent touching detection units in each touching detection column and each touching detection row so as to generate the capacitance varying order distribution. Furthermore, the number and the relative position of the touching points are determined according to the number of continuous symbol results in the capacitance varying order distribution. In addition, the coordinates of the touching point are positioned accurately with the absolute differences in the capacitance varying order distribution. [0051] Although the invention has been described with reference to the above embodiments, it is apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the invention. Accordingly, the scope of the invention is defined by the attached claims not by the above detailed descriptions.
A touch panel is disclosed. The touch panel mentioned above includes at least a touching detection column and a touching detection module. The detection column includes N first touching detection units, N is a positive integer. Each of the first touching detection units transfers a first capacitance varying value according to an area cover by a touching point. The touching detection module operates a differential operating on the first capacitance varying values from two of the first touching detection units which is disposed adjoining in sequential for obtaining a capacitance varying order distribution. The touching detection module obtains a number of at least one first touching point and coordinates thereof by calculating the capacitance varying order distribution.
Summarize the document in concise, focusing on the main idea's functionality and advantages.
[ "CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit of Taiwan application serial no. 98132452, filed on Sep. 25, 2009.", "The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.", "BACKGROUND OF THE INVENTION [0002] 1.", "Field of the Invention [0003] The invention relates to a touch panel, and more particularly, to a touching point detection method thereof.", "[0004] 2.", "Description of Related Art [0005] With the advancement in electronic techniques, consumers'", "demands on quality and functions of electronic products have increased as well.", "In order to attract the consumers by making the operation of these electronic products more convenient, various humanized human-machine interfaces have been proposed.", "[0006] In the various human-machine interfaces, the most common interface is the so-called touch panel.", "The touch panel is a device capable of receiving input signals such as contacts (i.e. fingers, stylus, and etc.) and the like.", "When the user's finger touches the touch panel, the touch sensor on the panel transmits back an electrical signal generated correspondingly.", "The touch signal is then utilized to determine the corresponding actions performed by the user on the touch panel.", "[0007] In a conventional capacitive touch panel, the number and the coordinates of the touching point are directly detected according to the capacitive varying value transmitted by the touch units disposed thereon.", "However, in the practical application, noises always cause various affects.", "Thus, in a conventional touch panel, many complicated circuit devices have to be disposed to reduce the noise in the environment, thereby increasing the manufacturing cost.", "Moreover, the forces the users exerted when touching on the touch panel are not the same, so the differentiation generated by different users is not often considered.", "Hence, conventional touch panels usually result in many inaccuracies when detecting the number of the touching point and the coordinates thereof.", "SUMMARY OF THE INVENTION [0008] The invention is directed to a touch panel configured to detect a number of a touching point accurately and positioning a location of the touching point.", "[0009] The invention is further directed to a method of detecting a touching point on a touch panel, and the method is configured to accurately detect a number of the touching point and positioning a location of the touching point.", "[0010] The invention provides a touch panel including at least one touching detection column and a touching point detection module.", "The touching detection column includes N first touching detection units, where N is a positive integer.", "Each first touching detection unit transmits a first capacitance varying value according to an area covered by a touching point.", "The touching point detection module is coupled to the first touching detection units to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units.", "Consequently, a first capacitance varying order distribution is obtained.", "The touching point detection module obtains a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution.", "[0011] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by an (i+1) th first touching detection unit from the first capacitance varying value transmitted by an i th first touching detection unit according to the arrangement order of the first touching detection units to perform the subtractive operation.", "Moreover, the touching point detection module subtracts the first capacitance varying value transmitted by an (i−1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit to perform the subtractive operation, where i is an even number.", "[0012] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by the (i+1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit according to the arrangement order of the first touching detection units to perform the subtractive operation.", "Moreover, the touching point detection module subtracts the first capacitance varying value transmitted by an (i−1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit to perform the subtractive operation, where i is an odd number.", "[0013] According to an embodiment of the invention, the touching point detection module subtracts the first capacitance varying value transmitted by the (i+1) th first touching detection unit from the first capacitance varying value transmitted by the i th first touching detection unit according to the arrangement order of the first touching detection units to operate the subtractive operation, where i is a positive integer.", "[0014] According to an embodiment of the invention, the touching point detection module obtains a plurality of symbol results and a plurality of absolute differences according to the subtractive operation.", "[0015] According to an embodiment of the invention, the touching point detection module further determines whether each of the absolute differences and each corresponding symbol result are recorded to the first capacitance varying order distribution according to a comparison result of each of the absolute differences and a threshold.", "[0016] According to an embodiment of the invention, the touching point detection module obtains the number of the first touching point according to the symbol results in the first capacitance varying order distribution.", "[0017] According to an embodiment of the invention, the touching point detection module obtains the coordinates of the first touching point according to the consecutive absolute differences in the first capacitance varying order distribution.", "[0018] According to an embodiment of the invention, the touch panel further includes at least one touching detection row.", "The touching detection row is coupled to the touching point detection module.", "The touching detection row includes M second touching detection units.", "Each second touching detection unit transmits a second capacitance varying value according to an area covered by the touching point, wherein M is a positive integer.", "[0019] According to an embodiment of the invention, the touching point detection module operates the subtractive operation on the second capacitance varying values transmitted by two adjacent second touching detection units according to an arrangement order of the second touching detection units to obtain a second capacitance varying order distribution.", "The touching point detection module obtains a number of the second touching point on the touch panel and coordinates of the second touching point according to the second capacitance varying order distribution.", "[0020] According to an embodiment of the invention, the touching point detection module further determines whether each of the absolute differences and each corresponding symbol result are recorded to the second capacitance varying order distribution according to a comparison result of each of the absolute differences and a threshold.", "[0021] According to an embodiment of the invention, the touching point detection module obtains the number of the second touching point according to a number of times consecutively showing the symbol results in the second capacitance varying order distribution.", "[0022] According to an embodiment of the invention, the touching point detection module obtains the coordinates of the second touching point according to the consecutive absolute differences in the second capacitance varying order distribution.", "[0023] The invention is further directed to a method of detecting a touching point on a touch panel.", "The method includes the following.", "Firstly, a plurality of first touching detection units is provided and therefore arranged into at least one touching detection column.", "A touching point detection module is provided to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units.", "As a consequence, a first capacitance varying order distribution is obtained.", "Finally, the touching point detection module is provided to obtain a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution.", "[0024] In light of the foregoing, the subtractive operation is operated by using the capacitance varying values transmitted by adjacent touching detection units in the same touching detection column or the same touching detection row.", "In addition, the number of the touching point and the coordinates of the touching point are determined according to the distribution of the symbol results obtained from the subtractive operation.", "Furthermore, the absolute differences obtained from the subtractive operation are applied to compensate the calculated coordinates of the touching point, so that the coordinates of the touching point can be marked more accurately.", "[0025] In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with drawings are described in detail below.", "BRIEF DESCRIPTION OF THE DRAWINGS [0026] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification.", "The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.", "[0027] FIG. 1A is a schematic view illustrating a touch panel 100 according to an embodiment of the invention.", "[0028] FIG. 1B illustrates another exemplary embodiment of the touch panel 100 .", "[0029] FIG. 2 is a schematic view illustrating a touch panel 200 according to another embodiment of the invention.", "[0030] FIG. 3 is a flowchart illustrating a method of detecting a touching point on a touch panel according to an embodiment of the invention.", "DESCRIPTION OF EMBODIMENTS [0031] Referring to FIG. 1A , FIG. 1A is a schematic view illustrating a touch panel 100 according to an embodiment of the invention.", "The touch panel 100 includes a touching detection column 110 having a plurality of touching detection units 111 ˜ 115 and a touching point detection module 120 .", "Each of the touching detection units transmits a corresponding capacitance varying value according to an area covered by a touching point.", "[0032] The touching point detection module 120 is coupled to the touching detection column 110 .", "When the touching point detection module 120 detects the touching point on the touching detection column 110 , the touching point detection module 120 operates a subtractive operation on capacitance varying values transmitted by two adjacent touching detection units according to an arrangement order of the touching detection units 111 ˜ 115 .", "In other words, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 111 , 112 according to an order from left to right as shown in FIG. 1 .", "Afterwards, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 114 , 115 .", "Accordingly, the detection is performed until the subtractive operation has been operated on the capacitance varying values transmitted by two adjacent touching detection units within all of the touching detection units 111 ˜ 115 .", "[0033] Obviously, the touching point detection module 120 also operates the subtractive operation in another order from right to left as shown in FIG. 1 .", "That is, the subtractive operation is first operated on the capacitance varying values transmitted by the touching detection units 115 , 114 .", "Afterwards, the touching point detection module 120 operates the subtractive operation on the capacitance varying values transmitted by the touching detection units 114 , 113 .", "Here, when the touching point detection module 120 detects the touching point, the order of executing the subtractive operation is not limited.", "[0034] Moreover, in the so-called subtractive operation, the touching point detection module 120 performs subtraction on the capacitance varying values transmitted by two adjacent touching detection units.", "In other words, the touching point detection module 120 subtracts the capacitance varying value transmitted by the touching detection unit 112 from the capacitance varying value transmitted by the touching detection unit 111 .", "Next, the touching point detection module 120 subtracts the capacitance varying value transmitted form the touching detection unit 112 from the capacitance varying value transmitted by the touching detection unit 113 .", "Accordingly, the touching point detection module 120 sequentially executes multiple subtractive operations aforementioned.", "Moreover, each subtractive operation result is recorded according to an order of executions to obtain a capacitance varying order distribution.", "[0035] The touching point detection module 120 can also subtracts the capacitance varying value transmitted by the touching detection unit 111 from the capacitance varying value transmitted by the touching detection unit 112 .", "Afterwards, the touching point detection module 120 subtracts the capacitance varying value transmitted by the touching detection unit 113 from the capacitance varying value transmitted by the touching detection unit 112 .", "Accordingly, multiple subtractive operations are executed in sequence to obtain the capacitance varying order distribution.", "[0036] That is, the touching point detection module 120 sets the capacitance varying values that are transmitted by the even number touching detection units 112 , 114 in the touching detection column 110 to be the subtrahend in the subtractive operation.", "In addition, the capacitance varying values that are transmitted by the odd number touching detection units 111 , 113 , 115 in the touching detection column 110 are set to be the minuend in the subtraction.", "Alternatively, the capacitance varying values that are transmitted by the odd number touching detection units 111 , 113 , 115 in the touching detection column 110 are set to be the subtrahend in the subtractive operation.", "Additionally, the capacitance varying values that are transmitted by the even number touching detection units 112 , 114 in the touching detection column 110 are set to be the minuend in the subtraction.", "[0037] It should be noted that a symbol result and an absolute difference are produced in every subtractive operation aforementioned.", "When the capacitance varying value transmitted by the touching detection unit set to be the minuend (i.e. the touching detection unit 111 ) is larger than the capacitance varying value transmitted by the touching detection unit set to be the subtrahend (i.e. the touching detection unit 112 ), the symbol result generated from the subtractive operation is “+.”", "On the contrary, in the case mentioned above, when the capacitance varying value transmitted the touching detection unit 111 is smaller than the capacitance varying value transmitted by the touching detection unit 112 , which is set to be the subtrahend, the symbol result generated from the subtractive operation is “−.”", "The absolute difference is an absolute value of the difference between the capacitance varying values of the touching detection units 111 , 112 .", "Further, when operating the subtractive operation, the touching point detection module 120 compares the calculated absolute difference with a predetermined threshold.", "When the absolute difference is smaller than the threshold, the touching point detection module 120 forsakes the result generated from this subtractive operation.", "When the absolute difference is larger than or equal to the threshold, the touching point detection module 120 records the symbol result and the absolute difference generated from the subtractive operation into the capacitance varying order distribution.", "The threshold is set to prevent the capacitance varying value transmitted by the touching detection unit from being affected by environmental noise, which leads to an erroneous touching point.", "For example, in the illustration of FIG. 1 , the range of a touching point 160 includes a small portion of touching detection unit 112 and most of the touching detection unit 113 .", "The touching detection units 114 , 115 are not covered at all.", "Theoretically, the capacitance varying values transmitted by the touching detection units 114 , 115 should both be 0.", "However, without setting the threshold, when the touching detection unit 115 generates a capacitance varying value larger than 0 due to the interference of environmental noise, the symbol result and the absolute difference generated from the subtractive operation of the touching detection units 114 , 115 are not 0, thereby affecting the result of the detection.", "[0038] The threshold can be set in accordance to actual usage and environment.", "When the detection of the touch panel is expected to be more sensitive, a lower threshold can be set in an environment with less interference.", "Oppositely, when the detection of the touch panel is expected to be more constant, a higher threshold can be set in an environment with more interference.", "An exemplary example is shown in the following to illustrate the operation of the touch panel 100 in the present embodiment.", "Referring to FIG. 1 , the range of the touching point 160 includes a small portion of the touching detection unit 112 and most of the touching detection unit 113 .", "Additionally, the touching detecting units 111 , 113 , 115 are set to minuend and the touching detecting units 112 , 114 are set to be subtrahend.", "The touching point detection module 120 operates the subtractive operation from right to left in sequence.", "Firstly, the touching point detection module 120 operates the subtractive operation on the touching detection units 111 , 112 , and a symbol result obtained is “−.”", "Thereafter, the touching point detection module 120 operates the subtractive operation on the touching detection units 112 , 113 .", "Since an area covered by the touching detection unit 113 is larger than an area covered by the touching detection unit 112 , the symbol result here is “+.”", "Next, the touching point detection module 120 operates the subtractive operation on the touching detection units 113 , 114 and consequently obtains a symbol result of “+.”", "Since the touching detection units 114 , 115 are not covered, the capacitance varying values thereof do not exceed the threshold.", "Thus, the symbol result obtained from the subtractive operation on the touching detection units 114 , 115 is 0.", "[0039] It should be noted that when a bit is used to record the symbol result of the subtractive operation of two adjacent touching detection units, “1”", "is utilized to represent the symbol result “+”", "and “0”", "is used to represent the symbol result “−.”", "Alternatively, “1”", "can be utilized to represent the symbol result “−”", "while “0”", "is used to represent the symbol result “+.”", "However, since a bit can not generate a third level to represent the symbol result “0”, “1”", "or “0”", "can be set to permanently represent the symbol result “0.”", "[0040] Therefore, in the present embodiment, the capacitance varying order distribution has symbol results of “−”", "“+”", "“+”", "“0.”", "Here, “0”", "means the symbol result of this subtractive operation is not recorded into the capacitance varying order distribution.", "From the capacitance varying order distribution, it is observed that a continuous symbol result (“−”", "“+”", "“+”) is present under the condition of this embodiment.", "Accordingly, the touching point detection module 120 determines the touch panel 100 of the present embodiment to include a touching point.", "[0041] From the illustrations aforementioned, when a plurality of touching points touches a touching apparatus 100 , the capacitance varying order distribution then shows changes in the continuous symbol results (“+”", "or “−”) that are equivalent to the numbers of touching points.", "The touching point detection module 120 can also obtain the numbers of more than one touching points according to the capacitance varying order distribution.", "[0042] Obviously, the touching detection units covered by the touching point 160 are also obtained by utilizing the capacitance varying order distribution.", "In addition, with the principle that the larger the area of the touching detection units covered by the touching point 160 , the larger the transmitted capacitance varying value is, a plurality of absolute differences in the capacitance varying order distribution is used to calculate the accurate coordinates of the touching point 160 .", "[0043] Referring to FIG. 1B , FIG. 1B illustrates another exemplary embodiment of the touch panel 100 .", "In the illustration in FIG. 1B , the subtractive operations of the capacitance varying values transmitted by two adjacent touching detection units are different from those illustrated in FIG. 1A .", "When the subtractive operation is operated on the touching detection units 112 , 113 in FIG. 1B , the capacitance varying value of the touching detection unit 113 is subtracted from the capacitance varying value of the touching detection unit 112 .", "That is, in the present embodiment, the capacitance varying value of the latter touching detection unit of two adjacent touching detection units is subtracted from the capacitance varying value of the former touching detection unit to complete the subtractive operation.", "[0044] From the illustrations in FIG. 1A and FIG. 1B , the subtrahend and the minuend of two adjacent touching detection units in the subtractive operation are not limited in the invention.", "The subtractive operations operated on the capacitance varying values transmitted by two adjacent touching detection units all belong within the protection range of the invention.", "[0045] Referring to FIG. 2 , FIG. 2 is a schematic view illustrating a touch panel 200 according to another embodiment of the invention.", "The touch panel 200 includes a plurality of touching detection columns disposed along axes 211 , 212 , 213 , 214 , and 215 , and a plurality of touching detection rows disposed along axes 221 , 222 , 223 , 224 , and 225 .", "The exemplary embodiments of the touching detection column and the touching detection column 110 illustrated in FIG. 1 are the same.", "The touching detection row and the touching detection column are disposed in perpendicular to each other.", "Take the touching detection row disposed along the axis 221 as an example, the touching detection row includes touching detection units 2211 , 2212 , 2213 , and 2214 .", "[0046] A touching point detection module 230 is coupled to all of the touching detection rows and touching detection columns.", "Here, the touching point detection module 230 operates the subtractive operation on each adjacent touching detection unit of each touching detection row to obtain the corresponding capacitance varying order distribution.", "Next, the touching point detection module 230 operates the subtractive operation on each adjacent touching detection unit of each touching detection column to obtain the corresponding capacitance varying order distribution.", "On the other hand, the touching point detection module 230 can first operate the subtractive operation on each adjacent touching detection unit of each touching detection column to obtain the corresponding capacitance varying order distribution, and then operate the subtractive operation on each adjacent touching detection unit of each touching detection row to obtain the corresponding capacitance varying order distribution.", "The operating method of the subtractive operation on the touching detection row is the same as the exemplary embodiment of the subtractive operation on the touching detection column, and is thus not repeated herein.", "[0047] That is, since the touching detection row and the touching detecting column both have touching detection units that are independent to one another, the touch panel 200 can obtain coordinates of the touching point in the perpendicular axis and horizontal axis to attain the ability of two-dimensional positioning.", "[0048] It should be noted that in the present embodiment, the touching point detection module 230 includes a plurality of difference calculators 231 ˜ 238 for respectively calculating differences in capacitance varying values of adjacent touching detection units in different touching detection rows and touching detection columns.", "Since the touching point detection module 230 only calculates the difference in capacitance varying values of two adjacent touching detection units at a time, only one difference calculator may be used.", "Moreover, the subtractive operation is performed by selecting the capacitance varying values of adjacent touching detection units to be calculated during a plurality of different timing periods through a multiplexer.", "[0049] Referring to FIG. 3 , FIG. 3 is a flowchart illustrating a method of detecting a touching point on a touch panel according to an embodiment of the invention.", "The method includes the following.", "Firstly, a plurality of first touching detection units is provided and arranged into at least one touching detection column (S 310 ).", "Next, a touching point detection module is provided to operate a subtractive operation on a plurality of first capacitance varying values transmitted by two adjacent first touching detection units according to an arrangement order of the first touching detection units.", "As a consequence, a first capacitance varying order distribution is obtained (S 320 ).", "Finally, the touching point detection module is provided to obtain a number of at least one first touching point on the touch panel and coordinates of the first touching point according to the first capacitance varying order distribution (S 330 ).", "The operation details of the method of detecting the touching point of the touch panel in the embodiment of the invention are illustrated in the different embodiments illustrated in FIGS. 1A , 1 B, and 2 , and thus are not repeated hereinafter.", "[0050] In summary, in the invention, the subtractive operation is sequentially operated on the capacitance varying values of two adjacent touching detection units in each touching detection column and each touching detection row so as to generate the capacitance varying order distribution.", "Furthermore, the number and the relative position of the touching points are determined according to the number of continuous symbol results in the capacitance varying order distribution.", "In addition, the coordinates of the touching point are positioned accurately with the absolute differences in the capacitance varying order distribution.", "[0051] Although the invention has been described with reference to the above embodiments, it is apparent to one of ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the invention.", "Accordingly, the scope of the invention is defined by the attached claims not by the above detailed descriptions." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus, an information processing system, a print control method and a storage medium storing a computer readable program, which can control a print job received from host equipment to be transferred to a printer, and particularly relates to an information processing apparatus, a print system, a print controlling method and a storage medium storing a computer readable program, as a print server that manages print jobs received from a plurality of client computers as host equipment on a group basis and controls the print jobs as a group job to be transmitted to a printer. 2. Related Background Art Conventionally, the printer system to which this type of information processing unit can be applied is configured to enable a printer to communicate with a client computer (PC), a server computer and the like, and is configured to store a print job received upon a job processing request from each client in a job spooler in the order of reception and sequentially analyze the print job and print it by the printer. Furthermore, print systems in recent years are configured such that the job name of a print job and the like spooled in a server can be displayed on a client, and there exist systems that make it possible to specify a print job and perform suspension and termination and even order control of the printing of specified print jobs depending on the authorization of the client by using network utility software installed in the client. Furthermore, as software operating on clients in recent years, there exist systems that enables batch print, by holding print jobs of PDL format generated by a printer driver without requesting a print server to print them, and transmitting by one operation a plurality of print jobs as a print request to a print server. However, in the above described utility software of prior art, it is possible to perform order control for print jobs spooled in a server (print server), but it is not possible to group a plurality of jobs and control the printing of the group job so as not to allow other print jobs to interrupt in the group job. Furthermore, for reducing the load on a network and a print server, it is conceivable that only a print request and job information are transmitted from the client to the print server, the order control is managed at the print server and the print job itself is spooled by the client making a print request, but it is impossible to print by one operation a plurality of jobs split and spooled in both the print server to be outputted to the same printer from different clients and the client, or to specify from a different client the order in which jobs client-spooled in the same group are processed. Furthermore, when print jobs are grouped, all print jobs to be grouped are not necessarily already prepared, and the user using a client computer can not necessarily make a request for printing a next print job in print order instantly from the client computer in every occasion, and it is conceivable that a print request is made after a considerable time because the user is absent for a certain time. In this case, since printing can not be started unless all print jobs that are grouped are ready for printing, in other words, unless the print jobs are ready to be transmitted to the printer, print jobs spooled in a server spooler at the print server and in a client spooler at each client must keep waiting, but in the conventional print queue, it is a precondition that the print job for which a print request is made is ready for printing and therefore the print job must be transmitted to the printer when turn for the print job to be printed comes in the print queue. Furthermore, in conventional software that enables batch print, print jobs from a single client can be printed by one operation, but print jobs generated from a plurality of clients can not be printed by one operation. Furthermore, in a conventional manner, a notification of completion is provided to the client making a request once an output of each print job is ended since the processing of group printing is not taken into account, thus not confirming the state of printing for all jobs printed in the same group and the fact that a set of printing has been properly done prior to provide the notification of completion to each client. Furthermore, there are disadvantages that if printing fails due to a printer error and the like before it is confirmed that printing for all the jobs in the group has been done, the user making a print request or the server cannot change the printing matter unless all the jobs in the group are consolidated and the client is notified thereof, a quick and flexible response cannot be made to the emergence of such an error, the group print operation remains suspended, and an intended result of printing operation cannot be obtained quickly. Furthermore, for the single print job, it is taken into account to change the printing matter in print systems in recent years, but it is not taken into account to change the printing matter for the grouping job as described above. Therefore, for the single print job, the ejection side is not a matter of concern so long as PDL is the same even when the printing matter is changed. That is because the print job is internally spooled and printing in invert page order is achieved due to the function of the printer itself. However, it is achieved due to the function of the printer itself only for the single job, and it not yet achieved for the grouping job considered in the present invention. SUMMARY OF THE INVENTION This invention is designed to solve the above described problems, and it is a first object of the present invention to enable print control that prevents a usual print job from being mixed with grouping print jobs for the same printer even if the usual print job is spooled together in the print server in the case where a plurality of print jobs for which requests for printing are made by a plurality of clients are grouped and then printed. Furthermore, it is a second object of the present invention to confirm that print jobs whose print operation is ended have been actually printed and ejected by one operation and inform the host computer of each print job that they have been printed by one operation. Furthermore, it is a third object of the present invention to change the printing matter to another printer by one operation if an error occurs in a printer before jobs to be printed are printed and ejected by one operation. Furthermore, it is a fourth object of the present invention to provide a mechanism in which a printer performs processing on the print job in the order of reception, thereby making it possible to maintain the proper order of printing even if the printing matter is changed to a printer whose ejection side is different. Furthermore, it is a fifth object of the present invention to provide a mechanism in which the grouping job where print jobs from a plurality of clients are grouped and printed is specified when a print request from the clients. An information processing unit as a server of the present invention has; identifying means for identifying first print jobs with a plurality of print jobs to be grouped and printed in succession and second print jobs to be printed as a single print job, based on print requests received from clients; determining means for determining whether all print jobs in a grouping print job corresponding to the above described print job are ready if the above described print request is a request for printing print jobs identified by the above described identifying means as the first print job; and controlling means for controlling the print of grouping print jobs for which it is determined by the above described determining means that all print jobs in the group are ready, while controlling the print of grouping print jobs for which it is determined by the above described determining means that all print jobs in the group are not yet ready to be held. Furthermore, a second information processing unit related to the present invention has; job managing means for managing grouping jobs with a plurality of print jobs to be grouped and printed in succession based on print requests received from a plurality of clients, determining means for determining the spooling matter spooling a plurality of print jobs included in the above described grouping jobs when the above described grouping jobs are printed, and transmission controlling means for controlling transmission so that print jobs determined by the above described determining means as being spooled in the above described clients transmit transmission permission information for permitting transmission of the above described print jobs to the above described client, and print jobs determined by the above described determining means as being spooled in their own spoolers transmit the above described print jobs spooled therein to a printer. Furthermore, a third invention related to the present invention has; acquiring means for acquiring information of grouping jobs being managed at a management server from the management server managing the order of printing grouping jobs with a plurality of print jobs to be grouped and printed in succession, first user interface providing means for providing a first user interface for specifying grouping jobs into which print jobs for which a print request is to be made are grouped based on the information of the grouping jobs acquired by the above described acquiring means, and print request making means for making a print request including indicative information to group print jobs into grouping jobs specified via the first user interface provided by the above described first user interface providing means. Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of an information processing system to which the present invention is applicable; FIG. 2 is a block diagram illustrating a configuration of an information processing unit that shows a first embodiment of the present invention; FIG. 3 illustrates an example of a memory map of a RAM shown in FIG. 2; FIG. 4 illustrates an example of a memory map of an FD shown in FIG. 2; FIG. 5 illustrates a relationship of an FD drive shown in FIG. 2 with the FD inserted therein; FIG. 6 is a block diagram illustrating a print control module configuration of an information processing unit that shows a first embodiment of the present invention; FIG. 7 illustrates an example of a data structure of job information common to a client and a server shown in FIG. 6; FIG. 8 illustrates an example of group specified information managed by a client machine shown in FIG. 6; FIG. 9 is a sequence diagram briefly illustrating a processing in the present invention; FIG. 10 is a flow chart of an example of a first data processing procedure in an information processing unit related to the present invention; FIG. 11 is a flow chart of an example of a second data processing procedure in an information processing unit related to the present invention; FIG. 12 is a flow chart of an example of a third data processing procedure in an information processing unit related to the present invention; FIG. 13 is a flow chart of an example of a data processing procedure in an information processing unit illustrating a second embodiment of the present invention; FIG. 14 is a flow chart of an example of a first data processing procedure in an information processing unit illustrating a third embodiment of the present invention; FIG. 15 is a flow chart of an example of a second data processing procedure in an information processing unit illustrating a third embodiment of the present invention; FIG. 16 illustrates an example of a data structure of group print information generated by a server machine shown in FIG. 6; FIG. 17 illustrates an example of a dialog box screen for specifying a group print provided by modules in a client; FIG. 18 illustrates an example of a graphical user interface screen displayed on the client in accordance with a group job management table managed at a print server; FIG. 19 illustrates an example of a graphical user interface for performing a print setting provided by a printer driver; and FIG. 20 illustrates a memory map of a storage medium storing each type of data processing program that can be read by a print system to which an information processing unit of the present invention is applicable. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a block diagram for explaining the configuration of an information processing system to which the present invention can be applied. It is assumed that the number of client computers connected to this system is n. In FIG. 1, reference numerals 102 , 103 and 104 denote information processors as client computers (client) which are connected to a network 106 by a network 106 by a network cable of an Ethernet or the like. These computers can execute various kinds of application programs and are loaded with printer drivers each having a function for converting print data into a printer language corresponding to a printer. Reference numeral 101 is an information processor as a server (called a print server, hereinafter) and connected to the network 106 by the network cable to accumulate files employed in the network or to monitor the using status of the network 106 . The print server 101 manages a plurality of printers connected to the network 106 . In the configuration, the clients 102 to 104 and the print server 101 serve as general information processors. In the clients and the print server, print control programs for performing respectively different controls are stored so as to be executable. The print server 101 in the first embodiment of the invention further includes functions for storing and printing print jobs having the print data for which print requests are issued from the client computers 102 , 103 and 104 , or receiving only job information including no print data from the client computers 102 , 103 and 104 , managing the print order of the client computers 102 , 103 and 104 , or informing the clients arranged in accordance with the print order of the transmit permission of the print jobs including the print data, obtaining a variety of kinds of information of the status or the print jobs of a network printer 105 or informing the client computers 102 , 103 and 104 of them. Reference numeral 105 denotes the network printer as a print controller which is connected to the network 106 through a network interface not shown. The network printer 105 analyzes the print job including the print data transmitted from the each client computer and converts it into a dot image one page by one page and prints each page. Reference numeral 106 denotes the network connected to the client computers 102 , 103 , 104 , the server 101 , the network server 105 or the like. FIG. 2 is a block diagram for explaining the configuration of an information processor according to the present invention. The client computers 102 , 103 , 104 as the information processors have the same configurations as the above. The server 101 also has a hardware configuration similar to the above configuration. Accordingly, FIG. 2 is shown as the block diagram for explaining the configurations of the clients and the server. In FIG. 2, reference numeral 200 denotes a CPU as the control means of the information processors and controls to execute application programs stored in a hard disk (HD) 205 , printer driver programs, OS and the control programs of the network printer control program of the present invention and to temporarily store in a RAM 202 information, files, etc. required for executing the programs. Reference numeral 201 denotes a ROM in which various data including programs such as basic I/O programs, font data utilized upon document processing, data for a template, etc. are stored. Reference numeral 202 denotes a RAM as temporarily storing means functioning as the main memory, the work area, etc. of the CPU 200 . Reference numeral 203 denotes a floppy disk (FD) drive as storing medium reading means which can load a main computer system with programs stored in an FD 204 as the storing medium through an FD drive 203 as shown in FIG. 5 described below. In this connection, the storing medium is not limited to the FD and may include a CD-ROM, a CD-R, a CD-RW, a PC card, a DVD, an IC memory card, an MO, a memory stick, etc. Reference numeral 204 denotes the floppy disk (FD) as the storing medium in which programs readable by a computer are stored. In this FD 204 , the network printer control program described in the present embodiment and related data are stored. The configuration of contents stored in the FD 204 will be described below by referring to FIG. 4 . Reference numeral 205 denotes the hard disk (HD) which is one of external storing means and functions as a large capacity storage memory in which the application program, the printer driver program, the OS, the network printer program, the associated program, etc. are stored. Further, a spooler as spooling means is maintained therein. The spooling means designates a client spooler in the clients, and a server spooler in the print server. Further, in the print server, a table for storing the job information received from the clients and controlling the order is also formed and stored in the external storing means. Reference numeral 206 denotes a keyboard as instruction input means through which a user instructs the client computer to input the instructions of the control command of a device, or an operator or a manager instructs the print server to input the instructions. Reference numeral 207 denotes a display as display means adapted to display the commands inputted from the keyboard 206 , and the state of the printer, etc. Reference numeral 208 denotes a system bus for governing the flow of data in the computers such as the clients or the print server. Reference numeral 209 denotes an interface as input and output means through which the information processors transmit data and receive data between an external device and them. FIG. 3 is a diagram showing an example of a memory map of the RAM 202 shown in FIG. 2 . The memory map shows a state in which the RAM 202 is loaded with the network printer control program unloaded from the FD 204 so that the program can be executed. According to the present embodiment, although an example in which the RAM 202 is loaded with the network printer control program and the associated data from the FD 204 so as to execute the program and data, the RAM 202 may be loaded with the network printer control program from the HD 205 in which the network printer program is already installed every time the network printer control program is operated from the FD 204 , with the exception of the above example. As media for storing the network printer control program, there may be exemplified the CD-ROM, the CD-R, the PC card, the DVD, the IC memory card except the FD. Further, the network printer control program may be stored in the ROM 21 . Then, the network printer control program is configured to form a part of the memory map so that it can be directly executed by the CPU 200 . Further, the network printer control program may be simply called a print control program. In the clients, the print control program includes programs for performing controls of designating grouping jobs as print jobs which are designated to be grouped and instructing a printer to be changed. In the print server, the print control program includes programs for controlling the order of the grouping jobs, managing the spools of all the print jobs in the grouping jobs and noticing the end of print of the grouping jobs or a request for change of a printer, etc. The print control program of the present invention for carrying out the above mentioned controls may be separately divided into a module installed in the clients and a module installed in the print serve. An execution part may be selected so that the print control program is installed by installing it once and it functions for the clients or for the print server depending on an environment where the print control program is executed. The print control program according to the present embodiment includes both the functions. Reference numeral 301 denotes a basic I/O program which is an area where a program with an IPL (initial program loading) function or the like for reading the OS to the RAM 202 from the HD 205 and starting the operation of the OS when the power of the controller is included. Reference numeral 302 denotes an operating system (OS). 303 designates the network printer control program and stored in an area ensured on the RAM 202 . 304 denotes the associated data and stored in an area ensured on the RAM 202 . 305 denotes a work area and an area for executing the printer control program by the CPU 200 is ensured therefor. FIG. 4 is a diagram showing one example of the memory map of the FD 204 shown in FIG. 2 . In FIG. 4, reference numeral 400 denotes the contents of the data of the FD 204 . 401 denotes volume information showing the information of the data. 402 denotes directory information. 403 designates the network printer control program as the print control program which s described in the present embodiment. 404 denotes the associated data thereof. The network printer control program 403 is programmed on the basis of a flowchart described in the present embodiment. According to the present embodiment, the configuration of the client is the same as that of the server. FIG. 5 is a view illustrating the relation between the FD 204 and the FD drive 203 shown in FIG. 2 into which the FD 204 is inserted. In FIG. 5, the parts the same as those shown in FIG. 2 are designated by the same reference numerals. In the FD 204 , the network printer control program described in the present embodiment and the related data are stored. FIG. 6 is a block diagram for explaining the configuration of the print control module of the information processor according to the present invention. Components the same as those shown in FIG. 1 are designated by the same reference numerals. Referring to FIG. 6, reference numeral 600 denotes a client machine in which a client module corresponding to the network printer control program as the print control program for executing a procedure shown in a flowchart described below. In the same figure, reference numeral 601 denotes an application software for creating documents or tables and outputs graphic drawing data to a graphic engine 602 upon displaying or printing. The graphic engine 602 is graphic drawing means provided by the OS, which indicates a GDI in the OS of Windows (registered trademark of Microsoft Corporation, in U.S.A.). The graphic engine 602 converts a GDI (Graphic Device Interface) function as the graphic drawing data outputted from the application 601 into a DDI (Device Driver Interface) function as graphic drawing data which can be interpreted by a printer driver 603 and outputs the DDI function to the printer driver 603 upon printing process. The printer driver 603 converts the DDI function into the print data including a PDL (Page Description Language) which can be interpreted by the printer on the basis of the DDI function received from the graphic engine 602 and outputs the print data as the print job with a JL (Job Language) added to a Windows Spooler 604 as a spooler provided by the OS. Further, the application 601 shifts its processing to the printer driver 603 upon set-up of printing. The printer driver 603 displays a graphical user interface screen on the display 207 as the display part to make a user perform various kinds of printing set-up. The spooler 604 of the OS sequentially delivers the print jobs received from the printer driver to a client spooler 606 . A client manager 605 monitors the client spooler 606 . When the spooler 606 begins to spool the print job, the client manager decides the set-up of the print job to extract jog information from the print job, in the case of the client spooler, to issue a print request to a print server 610 and to make a client spooler 606 spool the print job. On the other hand, in the case of a server spool, the client manager supplies the print job spooled in the client spooler 606 to the print server 610 as a print request to finish a print processing as the client. Further, when the client manager 605 receives a transmit permission notice of the print job from the print server 610 , the client manager begins to transmit the print job spooled on the client spooler 606 directly to a network printer. At this time, the print job spooled in the client spooler is not deleted but held. When the client manager 605 receives a print completion notice from the print server 610 , client manager can delete the spooled print job. Reference numeral 610 denotes a machine in which a print server module corresponding to the network printer control program as the print control program for executing a procedure shown in a flowchart described below. 611 denotes a server manager which receives a print request from each client through the network 106 . In the case where the print request is the print job including the print data, the print job is spooled in a server spooler 612 and the job information receiving the print request is managed in a job management table 613 . On the other hand, in the case when the print request is the job information including no print data, the job management table is updated on the basis of the job information. Further, the server manager 611 monitors the processing state of the job in each network printer, updates the job management table 613 every time the output of the print job is completed, and starts the transmission of subsequent print jobs. At this time, when the print jobs to be transmitted are spooled in the server spooler 612 , the print server 610 transmit them as they are. However, when the print jobs to be transmitted are spooled by the client spooler 606 , the transmit permission notice of the print jobs is supplied to its client. Further, the job management 613 (job managing means) has a print queue 615 for controlling a print order on the basis of the job information received from the client and managing an order for sequentially supplying the transmit permissions of the print jobs and a group job management table 616 for managing as to whether or not the information of all the print jobs in a group job is prepared. Reference numerals 105 and 650 denote network printers. In this connection, the above described classification is made depending on depending on the functions of respective devices. If both softwares are provided on the same information processors (machines), in other words, if the print server which the client asks to print is provided on the same machine, a communication between processes on the same machines can be executed without employing the network. A different machine operates as one client. Further, the spooler of the OS may internally include similar functions to these functions. FIG. 7 is a diagram showing one example of the data structure of the job information generated in the client and managed by the print server, as described with reference to FIG. 6 . This job information is information which shows the type of the print job created by the client manager 605 on the basis of the print job generated by the printer driver 603 of the client and is transmitted to the print server 610 as the print request. As shown in FIG. 7, the job information according to the present embodiment comprises a job ID for identifying the print job to the client from the print server, a printer name for designating a device to which the print job is outputted, a machine name as the host name of the client, the status of the print job, a document name extracted from the original document of the print job (generally, a document name designated in an application), the data size of the print job, a spool method for designating as to whether the print job is spooled by using the client spooler or by using the server spooler (0 or 1 bit expression may be utilized), a permission/inhibition of group print indicating as to whether or not the print job is grouped and controlled as a grouping job, a group name when the print job is grouped and printed as the grouping job, a print order in a group when the print job is grouped and printed, the number of jobs in a group showing the total number of print jobs included in the group when the print job is grouped and printed, etc. FIG. 8 is a diagram showing one example of group designating information managed by the client 600 shown in FIG. 6 . In the present embodiment, the group designating information is created when the client manager 605 receives the print job, as described below. Further, the group designating information may be generated by the printer driver on the basis of a value designated by a user in accordance with a user interface screen provided by the printer driver when a print step is designated from the application. As shown in FIG. 8, the group designating information in the present embodiment comprises a client name as the host name of the client, a group name (ID) showing a group name when the print job is grouped and printed, a print order in a group when the print job is grouped and printed, the total number of jobs in a group, etc. FIG. 9 is a sequence diagram of the present invention showing an example of a procedure for grouping and printing the print jobs received from the three clients. Initially, referring to FIG. 9, the procedures of the clients and the server in the group print according to the present invention will be described. In FIG. 9, the clients PC 1 , PC 2 , and PC 3 spool respective print jobs (print job 1 , print job 2 , and print job 3 ) in the client spoolers. Further, each client informs the print server of the job information. The print server groups the print jobs on the basis of the print information and prints them in accordance with a print order designated by each client, for example, an order of the print job 3 , the print job 2 and the print job 1 . Initially, the print job to be grouped and printed is generated and a client spooling step is carried out from the client PC 1 . In the case where the group job is first generated, the group designating information shown in FIG. 8 and the job information shown in FIG. 7 are generated simultaneously with the formation of the print job. The client PC 1 instructs the print server to perform a group print by using the group designating information and the job information. At this time, the print server generates the group information on the basis of the received group designating information and the job information, adds a new group job to the above described group job management table and manages it. The group job management table has cells of the total number of jobs in the group job and a state of “waiting for print” after receiving the job information is written in a proper cell on the basis of the information of the print order in the group included in the job information received from each client and the cell is updated. The server manager 611 monitors the group job management table 616 in the job management table 613 to decide whether or not all the status of cells with the total number of jobs of a group name of ION becomes a state of “waiting for print.” More specifically, when the server manager 611 decides that all the print jobs in the same group become a state of “waiting for print”, in other words, they are spooled by the clients or the server, it supplies a print request to a print queue for a printer to which the information is outputted and begins to control an order relative to other print jobs in order to start the printing step of the group job. Next, the job information (a group name is designated) shown in FIG. 7 is inputted to the print server from the client PC 3 and the client PC 2 and the group management table is respectively updated so that a print request is supplied to the print queue as mentioned above. In this case, the print order in the group is set to a sequence of the clients 1 , 2 and 3 . However, a timing at which the job information is supplied to the print server or a timing at which the job information is spooled in each spooler may be arbitrarily set, because the print order in the group is determined in the job information of each print job. When the client PC 1 shown in FIG. 9 starts the printing step of the print job to be grouped by the printer driver, the print job is spooled once in the spooler 604 of Windows, and then, the print job spooled similarly to an ordinary printing for the OS is outputted. The client manager 605 catches the outputted print job and spools it in the client spooler 606 . Then, the client manager decides the set-up of the print job and generates the job information while the client manager 605 spools the print job in the client spooler 606 and supplies it to the print server 610 as a print request, in the case of the client spool. Further, the job information may be generated by the printer driver 603 . On the other hand, in the case of the server spool, the client manager 605 supplies the print job spooled in the client spooler 606 to the print server 610 as the print request to spool the print job in the server spooler 612 of the print server. FIG. 10 is a flowchart showing one example of a first data processing procedure in the information processor according to the present invention, which corresponds to the spool processing procedure by the client 601 shown in FIG. 6 . Here, s 1001 to s 1006 designate respective steps. In the client 600 , when the application 601 starts a printing process, a user sets a printing step by employing a graphical user interface (see FIG. 19) for setting the printing step provided by the printer driver in step s 1001 . The printer driver 603 provides a graphical user interface screen for setting the print step and displays it on the display 207 through the OS. Referring to FIG. 19, 1901 denotes a menu capable of setting the types of print job. In “print” of the menu, a print job is generated for an ordinary printing process, and the print job is transmitted to the print server or the printer together with a print request. On the other hand, in “group print” in the menu, a print job is generated as a group print job (also called a grouping job. This print job is not spooled in the print server or the client. The job information is outputted to the print server. After print set-up values are set by the user, the application 601 begins to output the graphic drawing data to the graphic engine 602 , that is to say, starts a printing process. Thus, as mentioned above, the graphic engine receives the GDI function as the graphic drawing data, converts the GDI function into the DDI function and delivers it to the printer driver 603 . The printer driver 603 generates print data described by a page describing language on the basis of the received DDI function and supplies the print job to the Windows spooler 604 . The Windows spooler 604 outputs the received print job to the client manager 605 . When the client manager 605 starts a spool processing for the client spooler 606 of the print job received from the Windows spooler 604 , the client manager 605 obtains the job ID from the server manager 611 of the print server 610 and generates job information as shown in FIG. 7, for instance, JOB-INFO-2 of Windows. The job information except the “job ID” can be created on the basis of information in the client. For instance, the “printer name” may be the name or the path of a printer designated in a device to which the job information is outputted. As for the “document name,” the name of a document may be got from the application 601 . Further, the “permission/inhibition of group print” can be generated by judging whether the menu 1901 is set to the “group print” or the “print,” as mentioned above. Further, in the “spool method,” is generated information indicating that whether or not the check box of the server spooler in a spool method 1902 shown in FIG. 19 is checked, and, the server spooler is used when the check box is checked, and the client spooler is used when it is not checked. A communication method between the client and the server may depend on, for instance, a multiprotocol function such as RPC or a processing utilizing the communication function of Winsock or Win 32API and may not depend on a specific communication method. In step s 1002 , the client manager 605 decides whether or not this job is the job of the group print or an ordinary job by setting up the print step of the print job or viewing the “permission/inhibition of group print” of the generated job information. Further, while the “permission/inhibition of group print” is designated by a user upon instruction of a print by employing the graphical user interface for setting the print step of the printer driver, and then, the print is instructed, the display of the graphical user interface screen may be carried out by displaying a DLL registered as the port monitor of the Windows spooler 604 or a dialog in the client, every time data is supplied to the port as a contact for the Windows spooler 604 , or designating the screen as a port exclusively used for a group print for each port. For instance, the group printing may be automatically carried out on the basis of information capable of specifying the print job to be grouped by the printing system according to the invention, such as a prescribed document name employed by the application or an ID allocated uniquely by the Windows spooler 604 , etc. The above designation is different from an ordinary job only in respect of a point that designating information related to the group print is added to the job information of each job, so that this designation can be registered as a set-up for each port on the client. However, a special set-up is not needed for setting the printer or the printer server as common resources to other clients. When it is decided that the above job is the print job for a group printing in accordance with the decision in the step s 1002 , the client manager 605 supplies a dialog box for receiving a designation from a user shown in FIG. 17 to the OS and displays the dialog box on the display 207 . The dialog box shown in FIG. 17 can designate a group name (or ID) for designating the group print, the total number of jobs in the group and the print order as shown in FIG. 8 . The user designates the group name and the print order by using the keyboard 206 or a mouse, etc. As for a method for designating the group printing, since the group designating information may be designated for each job, any method for uniquely specifying the contents of the group designating information relative to information (document name, job ID, etc.) capable of a job may be possibly employed. Further, the designated values possessed by the client such as a registry or an INI file may be employed without display of the dialog box and a manual input, or a plurality of information may be held so that the user can select it. Next, in step s 1004 , the client manager 605 decides whether the grouping job is a new grouping job or a grouping job already registered in the print server 610 on the basis of the group name inputted by the user relative to the dialog of FIG. 17 displayed in step s 1003 . In other words, upon designation of the group name shown in FIG. 17, when a new name is inputted by the user, the client manager decides that it is a new grouping job. When a “reference button” 1701 is pushed to refer to the group name of the grouping job registered in the print server 610 , the client manager decides that the grouping job is the already registered group print. When it is decided that the grouping job is a new group print, the print manager shifts the process to step s 1005 . In the step s 1005 , the client manager 605 urges the user to manually input the information of a print order in the new group job and the total number of print jobs in the new group job. Further, the client manager 605 adds group print designating information including a group name, a print order in the group and the number of jobs in the group to the job information shown in FIG. 7 . In step s 1006 , the client manager 605 adds information including a group name (or ID), a print order, the total number of jobs, etc, for designating the group print shown in FIG. 8 to the job information of the print job, on the basis of the input of the dialog box. The present invention is described on the assumption that members for the group print are included in the job information. However, for instance, information capable of discriminating the group print is embedded in comment information or a document name so that the present embodiment can be realized without preparing special members (for instance, a character line such as Group 01-1-5 is added to a comment or a document name). Then, in step s 1007 , the client manager 605 performs a spool processing of the print job. The spool processing is performed in such a manner as described below. First, the client manager 605 views the “spool method” of the job information to decide whether the print job is the print job of the client spool or the print job of the server spool. When the client manager decides that it is the client spool, the client manager 605 spools the print job received from the Windows spooler 604 in the client spooler 606 so as to coordinate with the group designating information, and transmits the job information (see FIG. 7) and the group designating information (see FIG. 8) to the print server 610 . On the other hand, when the client manager decides that it is the print job of the server spool, the server manager 605 sends the print job, the job information and the group designating information to the print server 610 to open the printing step in the client 600 . Next, the spool procedure of the clients 2 and 3 , that is to say, a procedure for adding remaining print jobs to a proper grouping job will be described after the grouping job is set up. A procedure from steps s 1001 to s 1003 is the same as that of the above processing, and accordingly, the explanation thereof will be omitted. In step s 1004 , the client manager 605 decides whether the grouping job is a new grouping job or a grouping job already registered in the print server 610 on the basis of the group name inputted by the user for the dialog in FIG. 17 displayed in the step s 1003 . In the dialog shown in FIG. 17, when the “reference button” 1701 is pressed in accordance with the instruction of the user to refer to the group name of the grouping job registered in the print server 610 , the client manager decides that it is the registered group print and advances the process to step s 1009 . In the step s 1009 , the client manager 605 asks the server manager 611 of the print server 610 about the list of the grouping jobs spooled in the print server 610 . This inquiry means may be an ordinary communication between processes such as the RPC processing of API, for instance, the Enumjobs of Win 32API. For this inquiry, in the print server 610 , there will be carried out processings as mentioned below. Initially, when the server manager 611 receives the inquiry of the list of the grouping jobs from the client manager 605 , the server manager 611 refers to the group job management table 616 managed in the job management table 613 to generate the list of the grouping jobs to respond to the client manager 605 . Then, the server manager 611 returns the generated list to the client manager 650 . Further, in the cases other than the inquiry, various kinds of spool processings are carried out. When a print request including the job information is received from the client, the server manager 611 recognizes the print request and controls the job management table 613 to manage a print order. At this time, when the job management table 613 analyzes the job information to decide that the print request is the group print job, the job management table 613 updates the group job management table 616 so as to indicate that the job of a relevant print order is spooled in a new job or the already registered grouping job. At the same time, the server manager 611 spools the print job in the server spooler 612 . In the case where the spool method is the client spool, only the job information is managed and the spool processing is left to the client. In the step s 1009 , the client manager 605 acquires the list of the grouping jobs from the server manager 611 in accordance with the above inquiry, generates data for display and displays it on the display 207 through the OS as shown in FIG. 18 . FIG. 18 shows one example of a display screen formed by the client manager on the basis of the list of the grouping jobs managed by the group job management table. Reference numeral 1801 denotes the name of the grouping job managed by the print server 610 . 1803 denotes a print order in each group with the total number of jobs and the print order displayed. 1803 denotes the status of a print job. A notice of “waiting for print” indicates that the print job is already spooled. A notice of “not processed” indicates that a print job corresponding to a relevant print order has not been spooled yet. 1804 denotes a spool method. A “client” indicates the print job including print data is spooled in the client spooler 606 . A “server” indicates that the print job including print data is spooled in the server spooler 612 . 1805 denotes the name of a client who performs the print request of a corresponding print job. In the graphical user interface, the user can determine a selection state for each print job by using a pointing device such as the keyboard 206 or a mouse. In the example of FIG. 18, a second print job in the print order of a Group 2 located in a range shown in 1806 is selected. When an OK button 1807 is designated under this selected state, each item of the dialog for designating the group print illustrated in FIG. 17 is automatically selected. For instance, when the OK button 1807 is designated while the range of 1806 is selected, “Group 2” is inputted as the group name shown in FIG. 17, and “2/5” is automatically inputted as the print order. When the print job is designated by the user as shown in FIG. 18 in such a manner, the client manager 605 decides the group name of the designated print job in step s 1010 , and inputs the decided group name to the item of the group name. Subsequently, in step s 1011 , when the print job is designated by the user as shown in FIG. 18, the client manager 605 decides the print order and the total number of jobs of the print job and inputs them to the respective items. As described above, according to the present embodiment, the user designates the print job in the grouping job by using the graphical user interface screen so as to automatically input the respective items. The present invention is not limited thereto. For instance, the client manager 605 may get only the group name of the grouping job from the print server 610 to designate the grouping job therefrom, and then, the user may manually input the print order or the like. When various designations in the group print job are set, the procedure advances to a processing of step s 1006 . Steps after the step s 1006 are the same as those described above, and accordingly, the explanation thereof will be omitted. FIG. 16 is a diagram showing one example of the data structure of group print information created by the server manager 611 of the print server 610 shown in FIG. 6 . This group print information is formed on the basis of the job information and the group designating information received from the client. As illustrated in FIG. 16, according to the present embodiment, group names, the total number of jobs, printer names, printer status and job IDs, print orders, status and client names are included so that the number of them correspond to the number of jobs. Now, by referring to a flowchart shown in FIG. 11, there will be described a spool processing by the server manager 611 operating on the print server 610 shown in FIG. 6 . FIG. 11 is a flowchart showing a second data processing procedure in the information processor according to the present invention, which corresponds to the spool processing by the server manager 611 operating on the print server 610 shown in FIG. 6 . Here, s 1101 to s 1112 denote respective steps. In the step s 1101 , when the spool processing of a job from the client 600 is started, the server manager 611 generates a job ID and delivers the job ID to the client manager to perform a spool processing mentioned below in step s 1102 . In the step s 1102 , the server manager 611 receives job information and a print request from the client manager 606 . Further, the server manager 611 also receives group designating information from the client manager 606 as required. When the server manager 611 receives the print request, the server manager 611 updates a print queue in order to start the management of the print order as a result of receiving a new job in the print queue in the job management table 613 , and spools the print job received from the client in the server spooler 612 . When the server manager 611 does not receive the print job from the client, in other words, in the case of the print job subjected to the client spool processing, the client spools the print job, and the print server 610 manages the print order. Subsequently, in step s 1103 , the server manager 611 searches the job information delivered from the client manager 606 . Then, in step s 1104 , the server manager 611 decides whether or not the print job is a grouping job as a print job in which a group print is designated depending on the presence or absence of group print designating information in the job information. When the print job is the print job with a group print designation, proessings are different between the spool of the first job and the spool of a second job and jobs after that in the same group as described below. In step s 1105 , the server manager 611 decides whether or not the received print job is a new group print job on the basis of the job information and the group designating information. When it is decided that the print job is the new group print job, the procedure advances to step s 1106 . Otherwise, in other words, if group print information (GP-INFO) shown in FIG. 16 is already generated on a storage device, the processing advances to step s 1107 . In the step s 1106 , the server manager 611 generates the group print information (GP-INFO) and stores the new group print information in the group job management table 616 of the job management table 613 . This group print information GP-INFO is managed on the basis of list data for each printer in which the print step is designated. Then, in the step s 1107 , the server manager 611 records information peculiar to the job such as the printed client name (or address) or the print order in the group, etc. to the generated group print information (GP-INFO) from the job information. Next, in step s 1108 , the server manager 611 decides whether or not the print job is a first job in the print order in the same group. In this case, when the print job is the first job, the spool order of the job corresponds to the print order in the group. Therefore, the procedure advances to step s 1110 to finish the spool processing without changing the position of the job. Then, in the decision of the step s 1108 , when it is decided that the print job is not the first print job in view of the print order, the procedure moves to step s 1109 to arrange the job information of the print job so as to correspond to the sequence designated in the same group and to arrange the spool order of the print job in the server spooler 612 as required. Now, the spool order of the print jobs will be described below. This processing is carried out at the time of a spool processing of the print job of the server spool. More specifically, any job before the print job in the print order which is being processed, among jobs already spooled in the group print information (GP-INFO) moves just after that job. If only jobs after the print job in the print order which is being processed are spooled, that job will move so as to come to the first, and the procedure moves to step s 1110 to finish the spool processing. The print jobs are spooled in accordance with the print order as described above, so that the print jobs can be easily read upon print of the grouping job. However, even when the spool order of the print jobs does not correspond to the print order of the print jobs, the print processing of the jobs can be actually performed. On the other hand, in the step s 1104 , when it is decided that the spool is equal to a spool of the print job which is not the group print job, the procedure moves to step s 1111 . In the step s 1111 , the server manager 611 recognizes whether or not a present spool position interrupts jobs printed in accordance with the group print designation. If the server manager decides that the spool position of the print job interrupts the jobs with the group print designation in the same group to designate the change of another order such as a priority (in the case of YES), the server manager decides whether or not the jobs before and behind that spool position are of group print designation from the job information. In step s 1112 , the spool position is changed so as to spool the job behind the former position. In the step s 1111 , if an ordinary spool position does not interrupt the group print jobs, the procedure directly advances to step s 1110 to finish the spool processing. As for the print processing of the spooled print job, there will be described the processing of the server manager 611 of the print server 610 by referring to a flowchart shown in FIG. 12 . FIG. 12 is a flowchart showing. one example of a third data processing procedure in the information processor according to the present invention and corresponds to that of the server manager 611 in the print server 610 shown in FIG. 6 . This procedure is executed for a process unit like the thread of Windows in such a way that the server manager 611 monitors the status of a printer under the control connected to the network, manages spooled jobs, and successively starts the transmissions of the print jobs to proper printers. s 1201 to s 1208 denote respective steps. First, in step s 1201 , the server manager 611 monitors the status of the printer under the control. When the server manager decides that the print job can be transmitted to the monitored printer, this process is started. Then, in step s 1202 , the server manager 611 searches job information spooled in the job management table 613 . Then, in step s 1203 , the server manager decides whether or not the print job waiting for print is present among the print jobs to be transmitted to the proper printer in the job management table 613 . When this state is a steady state and there is no print job waiting for print, the server manager stays in the step s 1201 to continuously wait for a job to be spooled until it is decided that the job waiting for print exists in the step s 1203 . On the other hand, in the step s 1203 , when it is decided that there is a job waiting for print, the server manager 611 decides whether or not the print job waiting for print belongs to a group print. If the print jobs are arranged in the print order of group print designation, the server manager 611 analyzes the group job management table 616 in step s 1205 so that it decides whether or not all print jobs in the same group are spooled. In this case, when the server manager decides that all the print jobs in the group are spooled, the server manager 611 carries out the print processing of the grouping job in step s 1206 . Specifically, the server manager 611 ,transmits the print jobs sequentially spooled in accordance with the print order in the group to the printer. In this transmit processing, the server manager 611 recognizes the spool method of the print job in the print order, reads out the proper print job stored in the server spooler 612 in the case of the server spool, and transmits the print job to the printer through the network. Further, in the case of the client spool, the server manager 611 recognizes the client 1805 shown in FIG. 18 and supplies print transmit permission information including information for designating the job ID to the relevant client. When the transmit processing of print data to the printer 105 from the print server 610 or the client 600 is completed, the server manager 611 changes the status information of the group print information (GP-INFO) managed in the group job management table 616 and the group management table 610 shown in FIG. 6 to “end of transmission” to shift to a processing of the print job corresponding to a next print order. The jobs of the same group are continuously transmitted to the printer 105 to perform a print process by repeating the print procedure. On the other hand, in the step s 1205 , when it is decided that the print order of the first job of the same group is obtained before all the jobs in the same group are spooled so that all the print jobs of the same group are not spooled, the procedure advances to step s 1208 . The server manager 611 shifts its control to a next print job in the print queue for the relevant printer and returns to the step s 1203 to continue to process the next job similarly. In the step s 1204 , in the case where it is decided that the print job of the print order in the print queue 615 is an ordinary print job, the procedure directly moves to step s 1206 so that the server manager 611 performs the print processing (transmission control of the print job) as described above. The print processing is carried out in the print server 610 accordance with the above procedure. If the print is not recognized, after the transfer of data is completed, the group print information GP-INFO is deleted when the job is deleted. These procedures are performed, so that even when a plurality of series of print jobs printed at arbitrary timing by a plurality host computers are spooled in the print server under a state in which ordinary jobs mixed, or spooled in the client, they can be continuously printed together in regular order designated for the same printer. [Second Embodiment] Now, a second embodiment of the present invention will be described below. After the print jobs are printed in accordance with the procedure described in the first embodiment, the server manager 611 of the print server 610 may recognize the print state of each print similarly to the ordinary print job from the printer 105 , record it in the group print information and inform the client manager 605 of the client 600 in which the respective jobs are spooled of the end of print after recognizing the end of printing processes of all the print jobs in the group print information. The above matter will be described in the second embodiment. FIG. 13 is a flowchart showing one example of a fourth data processing procedure in the information processor according to the second embodiment of the present invention, which corresponds to a print recognition thread (detailed procedure of print recognition process) by the server manager 611 shown in FIG. 6 . Steps s 1301 to s 1312 denote respective steps. Initially, in step s 1301 , the print recognition thread is started. This thread may be started upon start of the server manager 611 and. stay until the power of the server machine 610 falls, or may be started only during a period after the print processing until the print recognition is obtained and the operation of the thread is finished at an arbitrary timing. Then, after the start of the thread, in step s 1302 , the server manager 611 monitors the status of the printer under control through the network to wait for the notice of print recognition from the printer 105 . In this recognition method, for instance, in the case of the network printer under the network environment of TCP/IP, the print server may carry out a polling using a command such as get of SNMP, or may receive a notice from the printer 105 by a trap or the like. Further, in the case the printer is connected to a local places, a communication through a center-cable may be employed and any protocol or any method for obtaining information may be utilized. In such a manner, when the notice of print recognition is sent to the server manager from the printer 105 , in step s 1303 , the server manager 611 decides whether or not a notice of error of the print job is sent from the printer 105 . When the server manager 611 decides that the notice of error is sent, the procedure moves to step s 1312 . Then, the server manager 611 recognizes the client of the related print job by using the group job management table shown in FIG. 18 and gives notice of an error to the client manager 605 of the relevant client 600 . On the other hand, in the step s 1303 , when the server manager decides that the notice of error is not sent from the printer, in step s 1304 , the server manager 611 decides whether or not the print job is the group print job from the job information of the print job in which the end of print is recognized. When the server manager decides that the print job is the job of group print, the server manager updates the status of the relevant print job in the group job information (GP-INFO) from “during printing” to “end of printing” in step s 1305 . Then, in step s 1306 , the server manager 611 decides whether the end of printing of all the print jobs in the group print job information (GP-INFO). When the server manager decides that there remain jobs which are being printed, the manager returns the process to the step s 1302 to wait for a notice of print recognition from the printer 105 . On the other hand, in the step s 1306 , when the server manager decides that a notice of print recognition of the last job in the group is sent from the printer, the server manager 611 shifts the process to step s 1307 to give notice to the client manager 605 of the client 600 supplying the print request for the print job in the group. After the server manager gives notice to each of the clients, the server manager 611 deletes all job information of the same group instep s 1308 . When the print job including print data remains in the server spooler 612 even after the print processing, the server manager 611 delete the print data as well as the job information. After the job information in the group is deleted in such a way, in the step s 1309 , the server manager 611 deletes the group print information whose print is finished and returns to the step s 1302 . On the other hand, in the step s 1304 , when a notice of print recognition of an ordinary job is sent from the printer, the server manager 611 gives notice to the client 601 of each client machine in step s 1310 , deletes the job in step s 1311 and returns to the step s 1302 . According to the above described procedure, the print recognition of the group print can be also done by hardly adding an excess processing to the procedure for recognizing the printing process of the ordinary job. Therefore, even when only the print recognition of each job can be obtained from the printer 105 , it can be recognized that the printed jobs are printed and discharged together, and a notice that the jobs are printed together can be given to a host computer supplying a print request for each print job. [Third Embodiment] According to the second embodiment, it is recognized that the print jobs for which the print requests are sent are printed and the printed jobs are discharged together and the notice that the print jobs are printed together is sent to the client (host computer) issuing the print request for each print job. However, any error may be possibly generated in the printer 105 during the printing process. In the case where an error is generated in the printer before the print jobs to which the print requests are issued are printed and the printed jobs are delivered together, a configuration may be used in which the destination where printing is performed is changed together to another printer on the network. Now, a third embodiment of the present invention will be described hereinafter. FIG. 14 is a flowchart showing an example of a fifth data processing procedure in the information processor showing the third embodiment of the present invention, which corresponds to the procedure for changing the printer to another printer by the server manager 611 in the print server 610 . Steps s 1401 to s 1414 denote respective steps. Further, in the third embodiment, the printing process is performed in accordance with the procedure of the first embodiment, and a process will be described after the print server is brought into a state in which the print server waits for print in accordance with the procedure of the second embodiment. First, in step s 1401 , when a process of print recognition is started, the server manager 611 is put to a state in which the server manager 611 acquires the status of the printer 105 or the print job on the basis of the notice from the printer 105 , or is waiting for receiving a notice from the client 601 . Next, in the step s 1402 , when a notice of the error of the print job is sent to the server manager 611 from the printer 105 , the server manager 611 decides whether or not the error corresponds to the error of the job after the transfer of data in step s 1403 . In this decision, the status of each job may be obtained directly from the printer 105 . When the error of the printer 105 is generated before the print recognition is not got, this may be judged as the error of the job. When the normal completion of the job cannot be recognized, it may be judged as the error of the job. In the step s 1403 , when it is decided that the error of the print job is an error after the transfer of data to the printer 105 , the server manager 611 searches the job information from a notified job ID to decide whether or not the print job is the group print job on the basis of the job information. Here, when it is decided that the print job is not the print job of the group print, the server manager 611 sets the status of the print job to “error” in step s 1405 , gives a notice that the job is printed to the client manager 605 of the client 600 in step s 1406 and returns to the step s 1402 to wait for a next recognition. On the other hand, in the step 1404 , when it is decided that the print job is the group print job, the server manager 611 updates the group print information (GP-INFO) in step s 1407 to judge the status of the print job of the group print information (GP-INFO) as an error. Next, in step s 1408 , the server manager 611 decides whether or not the substitute of the printer is designated upon error of the printer. This decision process is carried out after the client points out the error upon generation of the error, as described below. The information of a substitute printer name is previously added to the group designating information shown in FIG. 8 and the substitute printer name is managed in the group print information (GP-INFO) shown in FIG. 16 so that the server manager 611 can decide it. Here, when it is decided that the substitute printer for the currently employed printer is not designated, the server manager 611 only changes the status of the print job in the steps s 1405 and s 1406 similarly to the ordinary job, and then, gives a notice to the client manager 605 of the client 600 . In this case, the change of the printer is not executed until an instruction is sent to the server manager from the client manager 605 of the client 600 . On the other hand, in the step s 1408 , when the substitute printer for the printer is designated upon generation of an error, the procedure advances to step s 1409 , and the server manager 611 shifts all the job information in the group to the list data of a substitute printer, for instance, a printer 650 . Further, the management of the group print information (GP-INFO) is also shifted to the group print information list of the new printer. In this case, after the print server 611 changes the automatically spooling printer, in step s 1410 , the server manager 611 gives a notice of the change of a printer to the client of the client machine, After the printer is changed to another printer, the print jobs are printed as the jobs of the group print in a similar manner to that of the first embodiment. On the other hand, when an instruction is supplied so to change the printer to a substitute printer after steps 1402 and s 1403 shift to step s 1411 shown in FIG. 14, the server manager 611 decides whether or not the print job of the substitute printer designated by the client is the group print job in step s 1412 on the basis of the job information. When the print job is not the job of group print, the server manager 611 moves only the designated print job in step s 1413 . When the print job is the job of group print, the server manager updates group print information (GP-INFO) in step s 1414 , shifts to the steps s 1409 and s 1410 . The server manager 611 changes the output part of all the print jobs in the group to the substitute printer and spools the job information of the print jobs in the print queue in the relevant printer. The substitute printer may be designated on the basis of a registry, an INI file and information for managing the printers by the print server or the printers having the same printer driver may be selected at random. Accordingly, any method for designating the printer which can normally print created documents can be utilized. Now, there will be described a processing when the printer of the job is changed to other intended printers in accordance with the instruction of the user of the client 600 after the print recognition from the print server 610 is notified upon generation of the error. FIG. 15 is a flowchart showing one example of a sixth data processing procedure in the information processor showing the third embodiment of the present invention, which corresponds to the procedure of print recognition of the client manager 605 and the procedure for changing the printer of the group print in the client manager 605 (a printer change procedure after notification of the error of the job). s 1501 to s 1511 denote respective steps. First, in step s 1501 , the above described process is started upon start of the client manager 605 or after the print processing, the client manager 605 is waiting for an instruction in step s 1502 . When any instruction is sent to the client manager 605 from the server manager 611 , in step s 1503 , the client manager 605 decides whether or not the instruction is the notification of print recognition in other words, the print confirmation. Whether or not the printer is changed to the substitute printer, the print confirmation is similarly carried out. In step s 1503 , when it is decided that the print confirmation is supplied to the client manager, in step s 1504 , the client manager 605 provides, for example, the graphical user interface screen showing the change of the status or the like such as the dialog box or the print manager print manager and displays the print confirmation or notification on the display 207 through the OS to give a notice to the user. Then, the procedure returns to the step s 1502 after the confirmation. In case of the group print, after the confirmation process to the client is finished, the job information is deleted. Therefore, for this display process, a special display for indicating that the print confirmation of the group print is completed may be done by obtaining the job information or the group print information from the server manager 611 of the print server 610 . On the other hand, in step s 1503 , when it is decided that the notice is not the print confirmation, the client manager 605 decides in step s 1505 whether or not the notice is an error notice. When the client manager 605 decides that the notice is the error notice, the procedure advances to step s 1506 . The client manager 605 provides a dialog showing the error of a job to display it on the display 207 through the OS and notify the user of the error. In this display, the client manager 605 may give a notice to the user as the change of the status of the print job like the print manager of Windows without displaying a special notice message. Then, after the notice of an error is displayed, in step s 1507 , the client manager 605 provides a user interface (UI) for changing the printer such as the dialog box of Windows and displays the notice on the display 207 shown in FIG. 2 . Next, in step s 1508 , the client manager 605 decides whether or not the printer of the job is instructed to be changed in accordance with the instruction of the user. When the client manager 605 decides that the printer of the job is instructed to be changed to a substitute, the procedure advances to step s 1509 . The client manager 605 notifies the server manager 611 of the server 610 of the substitute printer to return to the step s 1502 . Even in the case of the job, only the substitute printer may be designated relative to the print job whose printer is to be changed. Further, when the printer is changed to a substitute by the server manager 611 , a notice of change of the printer is sent from the sever manager 611 . In this case, the procedure advances to the steps s 1503 and s 1505 from the step s 1502 for waiting for an instruction. Instep s 1510 , the client manager 605 decides whether or not the instruction for changing the printer is sent. When the instruction for changing the printer is not supplied to the client manager, the procedure returns to the step s 1502 . When the client manager 605 decides that the instruction for changing the printer is sent, the procedure moves to step s 1511 to notify the user of the substitute printer through the dialog box or the like on the display 207 shown in FIG. 2 . Then, the procedure returns to step s 1502 . In this case, after the printer changing process of the job is completed, only a notice of the changed result is sent or displayed. The server manager 611 of the print server 610 instructed to change the printer from the client manager 605 of the client 600 as described above moves to the steps S 1402 , s 1403 and s 1411 shown in FIG. 14 . In case of the instruction for changing the printer, the server manager 611 decides whether or not the job for which the change of the printer is instructed by the client is the job of group print on the basis of the job information. When the job is not the job of group print, the server manager 611 moves only the designated job in the step s 1413 . When the job is the job of group print, the server manager updates the GP-INFO to move to the steps 1409 and s 1410 and spool all the jobs in the group in the substitute printer. Further, when the printer of the grouping job is changed, the server manager 611 decides as follows. First, the server manager 611 decides whether the substitute printer is a face-up printer or a face-down printer. When the substitute printer is the face-down printer, the print job may be printed from its head, so that the print job may be controlled to be transmitted in accordance with the print order of the print order of the group designating information (GP-INFO) managed by the group job management table 616 . On the other hand, when the substitute printer is the face-up printer, the print job must be printed from its end. As for the order of pages of one print job, the print job may be spooled in the printer so that a printing operation can be performed successively from the last page thereof by using the function of the printer. However, in the case of the grouping job in which a plurality of print jobs are grouped to treat them as one print job, the transmission control needs to be performed from the end of the print order of the group designating information. Therefore, in the case where the printer is changed to the face-up printer, the spool methods are decided successively from the last print job in the print order designated by the group designating information. Then, when it is decided that the server spooler 612 is employed, the print job spooled in the server spooler is transmitted. When it is decided that the client spooler 606 is employed, a transmit permission information is sent to the client manager 605 of the client issuing the print request for the print job to be printed. Further, when the printer is changed from the face-up printer to the face-down printer, the server manager 611 may control the transmission of the print job by changing a print order reverse to a normal print order. Under this control, even when the printer is changed to a printer whose paper discharge method is different from the former printer, a printing process can be effected while the paper discharge order of the grouping job is ensured. The change of the printer can be designated by any client. However, when instructions are first outputted from other clients, only a changed result is displayed to each client like the process for automatically changing the printer of the print server. In accordance with the above described procedure, when a printing operation cannot be continuously performed due to the error of the printer 105 or the like before the end of all the print jobs in the group is recognized, the print server 611 can automatically change the printer to a printer designated upon default or can completely change the printer to the substitute printer in accordance with the instruction of the client manager 605 of the client 600 . In the above described embodiment, although the network printer is employed as the example, it should be noted that the present invention is not limited to the network printer, and any printer capable of transmitting data from the print server and obtaining the status information, such as a printer locally connected to the print server, may be utilized. To the case where there is provided only the spool of the job information like a virtual print server system, and, the case where a print server function is installed in the network printer, the present invention can be applied. According to each of the embodiments, even when a plurality of jobs are printed at arbitrary timing by a plurality of clients, the jobs can be printed together in the print order designated by the printer. Further, according to the embodiments of the invention, each client PC can recognize that all the jobs printed together are completely printed. Further, when the printing of the jobs to be printed together cannot be recognized, the printer can be changed to the substitute printer so as to print a plurality of jobs together. Now, the configuration of a data processing program which can be read by a print system to which the information processor of the present invention can be applied by referring to a memory map shown in FIG. 20 . FIG. 20 is a diagram for explaining the memory map of a memory medium for storing various types of data processing programs readable by the print system to which the present invention can be applied. Information for managing program groups stored in the memory medium, which is not particularly shown, for instance, version information, an implement or, etc. is also stored in the memory medium. In addition, information depending on the OS of a program read side, for instance, icons or the like for identifying and displaying the programs may be stored in the memory medium. Further, data dependent upon a variety of programs is managed by the above described directory. Still further, programs for installing these programs in a computer or a program or the like for thawing the installed program when it is compressed, etc. may be stored in the memory medium. The functions shown in FIGS. 10 to 15 in the above embodiments may be executed by the host computer on the basis of an externally installed program. In this case, when the information groups including programs are supplied to an output device from the external memory medium by the memory medium such as a CD-ROM, a flash memory or an FD, or through the network, the present invention may be applied. As mentioned above, needless to say, the memory medium on which the program code of software for achieving the functions of the above described embodiments is stored is supplied to the system or the device, and the system or the computer (or a CPU or a MPU) of the device reads and executes the program code stored in the memory medium so that the object of the present invention can be realized. In that case, the program code itself read from the memory medium realizes the new function of the present invention and the memory medium on which the program code is stored configures the present invention. As the memory medium for supplying the program code, for instance, a floppy disk, a hard disk, an optical disk, a photomagnetic disk, a CD-ROM, a CD-R, a CDRW, a DVD, a magnetic tape, a nonvolatile memory card, a ROM, an EEPROM, etc. may be employed. Further, it should be noted that the program code read by the computer is executed so that not only the functions of the embodiments can be realized, but also the OS (operating system) operating on the computer or the like performs a part or all of the actual processings by which the above described functions of the embodiments may be realized. Further, it should be noted that, after the program code read from the memory medium is written in a memory provided in a function expanding board inserted into the computer or a function expanding unit connected to the compute, a CPU or the like provided in the function expanding board or the function expanding unit performs a part or all of the actual processings, by which the functions of the above described embodiments may be realized. As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims. As mentioned above, according to the present invention, since a plurality of print jobs for which the print requests are supplied from a plurality of clients are controlled and printed before all the print jobs to be grouped are prepared, even when ordinary print jobs are mixed therein and they are spooled in the print server, the printing process of the same printer can be controlled without mixing the ordinary print jobs in the group print job. Further, the print jobs are spooled in the client, so that the load of the network and the print server can be reduced, and the print jobs spooled in the client and the print jobs spooled in the print server can be grouped, and the print jobs can be successively transmitted and controlled according to the print order. Still further, even when the print information for each print job can be merely obtained from the printer, the print jobs whose print operations are finished can recognized that they are printed and discharged together and inform the client of each print job that the print jobs are printed together. Further, when the print jobs cannot be printed due to the error of the printer, the printer can be together changed to another designated printer. Further, when the printer is changed to a printer whose discharge surface is different from that of the former printer, the printer processes the print jobs in regular order by which the print jobs are received, so that a print control can be performed while a proper print order for the grouping job is maintained. Accordingly, even when the print jobs to be formed in an order different from the print order are successively received, they can be edited freely so as to meet the designated order, and the print jobs can be continuously printed by the same printer in an order intended by the user and can flexibly meet troubles during the printing process of the printer, the manner of the processing order of the print jobs of the printer can be expanded and the process of the printing function can be extremely improved. Therefore, the present invention can achieve excellent effects as mentioned above. Still further, the print jobs to be printed can be grouped relative to the group print jobs already managed by the management server. Furthermore, upon print request by the client, the user can designate a new grouping job obtained by grouping printing the print jobs from a plurality of clients. Additionally, when the print jobs are included in the group print job already managed by the management server, the user can easily designate the group name or the print order by employing the graphical user interface.
The object is to print continuously in the specified order by one operation a series of print jobs printed in any timing by a plurality of host computers for the same printer even if a usual print job is spooled together in a print server. In a method for solving the problem, a print server identifies ordered print jobs for which print order is to be specified and non-ordered print jobs out of a plurality of print jobs transmitted in any timing from a client, the print order for each print job identified as such is rearranged and aligned in specified order, and the output order for each print job aligned for a printer based on the state of alignment.
Summarize the key points of the given document.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to an information processing apparatus, an information processing system, a print control method and a storage medium storing a computer readable program, which can control a print job received from host equipment to be transferred to a printer, and particularly relates to an information processing apparatus, a print system, a print controlling method and a storage medium storing a computer readable program, as a print server that manages print jobs received from a plurality of client computers as host equipment on a group basis and controls the print jobs as a group job to be transmitted to a printer.", "Related Background Art Conventionally, the printer system to which this type of information processing unit can be applied is configured to enable a printer to communicate with a client computer (PC), a server computer and the like, and is configured to store a print job received upon a job processing request from each client in a job spooler in the order of reception and sequentially analyze the print job and print it by the printer.", "Furthermore, print systems in recent years are configured such that the job name of a print job and the like spooled in a server can be displayed on a client, and there exist systems that make it possible to specify a print job and perform suspension and termination and even order control of the printing of specified print jobs depending on the authorization of the client by using network utility software installed in the client.", "Furthermore, as software operating on clients in recent years, there exist systems that enables batch print, by holding print jobs of PDL format generated by a printer driver without requesting a print server to print them, and transmitting by one operation a plurality of print jobs as a print request to a print server.", "However, in the above described utility software of prior art, it is possible to perform order control for print jobs spooled in a server (print server), but it is not possible to group a plurality of jobs and control the printing of the group job so as not to allow other print jobs to interrupt in the group job.", "Furthermore, for reducing the load on a network and a print server, it is conceivable that only a print request and job information are transmitted from the client to the print server, the order control is managed at the print server and the print job itself is spooled by the client making a print request, but it is impossible to print by one operation a plurality of jobs split and spooled in both the print server to be outputted to the same printer from different clients and the client, or to specify from a different client the order in which jobs client-spooled in the same group are processed.", "Furthermore, when print jobs are grouped, all print jobs to be grouped are not necessarily already prepared, and the user using a client computer can not necessarily make a request for printing a next print job in print order instantly from the client computer in every occasion, and it is conceivable that a print request is made after a considerable time because the user is absent for a certain time.", "In this case, since printing can not be started unless all print jobs that are grouped are ready for printing, in other words, unless the print jobs are ready to be transmitted to the printer, print jobs spooled in a server spooler at the print server and in a client spooler at each client must keep waiting, but in the conventional print queue, it is a precondition that the print job for which a print request is made is ready for printing and therefore the print job must be transmitted to the printer when turn for the print job to be printed comes in the print queue.", "Furthermore, in conventional software that enables batch print, print jobs from a single client can be printed by one operation, but print jobs generated from a plurality of clients can not be printed by one operation.", "Furthermore, in a conventional manner, a notification of completion is provided to the client making a request once an output of each print job is ended since the processing of group printing is not taken into account, thus not confirming the state of printing for all jobs printed in the same group and the fact that a set of printing has been properly done prior to provide the notification of completion to each client.", "Furthermore, there are disadvantages that if printing fails due to a printer error and the like before it is confirmed that printing for all the jobs in the group has been done, the user making a print request or the server cannot change the printing matter unless all the jobs in the group are consolidated and the client is notified thereof, a quick and flexible response cannot be made to the emergence of such an error, the group print operation remains suspended, and an intended result of printing operation cannot be obtained quickly.", "Furthermore, for the single print job, it is taken into account to change the printing matter in print systems in recent years, but it is not taken into account to change the printing matter for the grouping job as described above.", "Therefore, for the single print job, the ejection side is not a matter of concern so long as PDL is the same even when the printing matter is changed.", "That is because the print job is internally spooled and printing in invert page order is achieved due to the function of the printer itself.", "However, it is achieved due to the function of the printer itself only for the single job, and it not yet achieved for the grouping job considered in the present invention.", "SUMMARY OF THE INVENTION This invention is designed to solve the above described problems, and it is a first object of the present invention to enable print control that prevents a usual print job from being mixed with grouping print jobs for the same printer even if the usual print job is spooled together in the print server in the case where a plurality of print jobs for which requests for printing are made by a plurality of clients are grouped and then printed.", "Furthermore, it is a second object of the present invention to confirm that print jobs whose print operation is ended have been actually printed and ejected by one operation and inform the host computer of each print job that they have been printed by one operation.", "Furthermore, it is a third object of the present invention to change the printing matter to another printer by one operation if an error occurs in a printer before jobs to be printed are printed and ejected by one operation.", "Furthermore, it is a fourth object of the present invention to provide a mechanism in which a printer performs processing on the print job in the order of reception, thereby making it possible to maintain the proper order of printing even if the printing matter is changed to a printer whose ejection side is different.", "Furthermore, it is a fifth object of the present invention to provide a mechanism in which the grouping job where print jobs from a plurality of clients are grouped and printed is specified when a print request from the clients.", "An information processing unit as a server of the present invention has;", "identifying means for identifying first print jobs with a plurality of print jobs to be grouped and printed in succession and second print jobs to be printed as a single print job, based on print requests received from clients;", "determining means for determining whether all print jobs in a grouping print job corresponding to the above described print job are ready if the above described print request is a request for printing print jobs identified by the above described identifying means as the first print job;", "and controlling means for controlling the print of grouping print jobs for which it is determined by the above described determining means that all print jobs in the group are ready, while controlling the print of grouping print jobs for which it is determined by the above described determining means that all print jobs in the group are not yet ready to be held.", "Furthermore, a second information processing unit related to the present invention has;", "job managing means for managing grouping jobs with a plurality of print jobs to be grouped and printed in succession based on print requests received from a plurality of clients, determining means for determining the spooling matter spooling a plurality of print jobs included in the above described grouping jobs when the above described grouping jobs are printed, and transmission controlling means for controlling transmission so that print jobs determined by the above described determining means as being spooled in the above described clients transmit transmission permission information for permitting transmission of the above described print jobs to the above described client, and print jobs determined by the above described determining means as being spooled in their own spoolers transmit the above described print jobs spooled therein to a printer.", "Furthermore, a third invention related to the present invention has;", "acquiring means for acquiring information of grouping jobs being managed at a management server from the management server managing the order of printing grouping jobs with a plurality of print jobs to be grouped and printed in succession, first user interface providing means for providing a first user interface for specifying grouping jobs into which print jobs for which a print request is to be made are grouped based on the information of the grouping jobs acquired by the above described acquiring means, and print request making means for making a print request including indicative information to group print jobs into grouping jobs specified via the first user interface provided by the above described first user interface providing means.", "Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating a configuration of an information processing system to which the present invention is applicable;", "FIG. 2 is a block diagram illustrating a configuration of an information processing unit that shows a first embodiment of the present invention;", "FIG. 3 illustrates an example of a memory map of a RAM shown in FIG. 2;", "FIG. 4 illustrates an example of a memory map of an FD shown in FIG. 2;", "FIG. 5 illustrates a relationship of an FD drive shown in FIG. 2 with the FD inserted therein;", "FIG. 6 is a block diagram illustrating a print control module configuration of an information processing unit that shows a first embodiment of the present invention;", "FIG. 7 illustrates an example of a data structure of job information common to a client and a server shown in FIG. 6;", "FIG. 8 illustrates an example of group specified information managed by a client machine shown in FIG. 6;", "FIG. 9 is a sequence diagram briefly illustrating a processing in the present invention;", "FIG. 10 is a flow chart of an example of a first data processing procedure in an information processing unit related to the present invention;", "FIG. 11 is a flow chart of an example of a second data processing procedure in an information processing unit related to the present invention;", "FIG. 12 is a flow chart of an example of a third data processing procedure in an information processing unit related to the present invention;", "FIG. 13 is a flow chart of an example of a data processing procedure in an information processing unit illustrating a second embodiment of the present invention;", "FIG. 14 is a flow chart of an example of a first data processing procedure in an information processing unit illustrating a third embodiment of the present invention;", "FIG. 15 is a flow chart of an example of a second data processing procedure in an information processing unit illustrating a third embodiment of the present invention;", "FIG. 16 illustrates an example of a data structure of group print information generated by a server machine shown in FIG. 6;", "FIG. 17 illustrates an example of a dialog box screen for specifying a group print provided by modules in a client;", "FIG. 18 illustrates an example of a graphical user interface screen displayed on the client in accordance with a group job management table managed at a print server;", "FIG. 19 illustrates an example of a graphical user interface for performing a print setting provided by a printer driver;", "and FIG. 20 illustrates a memory map of a storage medium storing each type of data processing program that can be read by a print system to which an information processing unit of the present invention is applicable.", "DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a block diagram for explaining the configuration of an information processing system to which the present invention can be applied.", "It is assumed that the number of client computers connected to this system is n. In FIG. 1, reference numerals 102 , 103 and 104 denote information processors as client computers (client) which are connected to a network 106 by a network 106 by a network cable of an Ethernet or the like.", "These computers can execute various kinds of application programs and are loaded with printer drivers each having a function for converting print data into a printer language corresponding to a printer.", "Reference numeral 101 is an information processor as a server (called a print server, hereinafter) and connected to the network 106 by the network cable to accumulate files employed in the network or to monitor the using status of the network 106 .", "The print server 101 manages a plurality of printers connected to the network 106 .", "In the configuration, the clients 102 to 104 and the print server 101 serve as general information processors.", "In the clients and the print server, print control programs for performing respectively different controls are stored so as to be executable.", "The print server 101 in the first embodiment of the invention further includes functions for storing and printing print jobs having the print data for which print requests are issued from the client computers 102 , 103 and 104 , or receiving only job information including no print data from the client computers 102 , 103 and 104 , managing the print order of the client computers 102 , 103 and 104 , or informing the clients arranged in accordance with the print order of the transmit permission of the print jobs including the print data, obtaining a variety of kinds of information of the status or the print jobs of a network printer 105 or informing the client computers 102 , 103 and 104 of them.", "Reference numeral 105 denotes the network printer as a print controller which is connected to the network 106 through a network interface not shown.", "The network printer 105 analyzes the print job including the print data transmitted from the each client computer and converts it into a dot image one page by one page and prints each page.", "Reference numeral 106 denotes the network connected to the client computers 102 , 103 , 104 , the server 101 , the network server 105 or the like.", "FIG. 2 is a block diagram for explaining the configuration of an information processor according to the present invention.", "The client computers 102 , 103 , 104 as the information processors have the same configurations as the above.", "The server 101 also has a hardware configuration similar to the above configuration.", "Accordingly, FIG. 2 is shown as the block diagram for explaining the configurations of the clients and the server.", "In FIG. 2, reference numeral 200 denotes a CPU as the control means of the information processors and controls to execute application programs stored in a hard disk (HD) 205 , printer driver programs, OS and the control programs of the network printer control program of the present invention and to temporarily store in a RAM 202 information, files, etc.", "required for executing the programs.", "Reference numeral 201 denotes a ROM in which various data including programs such as basic I/O programs, font data utilized upon document processing, data for a template, etc.", "are stored.", "Reference numeral 202 denotes a RAM as temporarily storing means functioning as the main memory, the work area, etc.", "of the CPU 200 .", "Reference numeral 203 denotes a floppy disk (FD) drive as storing medium reading means which can load a main computer system with programs stored in an FD 204 as the storing medium through an FD drive 203 as shown in FIG. 5 described below.", "In this connection, the storing medium is not limited to the FD and may include a CD-ROM, a CD-R, a CD-RW, a PC card, a DVD, an IC memory card, an MO, a memory stick, etc.", "Reference numeral 204 denotes the floppy disk (FD) as the storing medium in which programs readable by a computer are stored.", "In this FD 204 , the network printer control program described in the present embodiment and related data are stored.", "The configuration of contents stored in the FD 204 will be described below by referring to FIG. 4 .", "Reference numeral 205 denotes the hard disk (HD) which is one of external storing means and functions as a large capacity storage memory in which the application program, the printer driver program, the OS, the network printer program, the associated program, etc.", "are stored.", "Further, a spooler as spooling means is maintained therein.", "The spooling means designates a client spooler in the clients, and a server spooler in the print server.", "Further, in the print server, a table for storing the job information received from the clients and controlling the order is also formed and stored in the external storing means.", "Reference numeral 206 denotes a keyboard as instruction input means through which a user instructs the client computer to input the instructions of the control command of a device, or an operator or a manager instructs the print server to input the instructions.", "Reference numeral 207 denotes a display as display means adapted to display the commands inputted from the keyboard 206 , and the state of the printer, etc.", "Reference numeral 208 denotes a system bus for governing the flow of data in the computers such as the clients or the print server.", "Reference numeral 209 denotes an interface as input and output means through which the information processors transmit data and receive data between an external device and them.", "FIG. 3 is a diagram showing an example of a memory map of the RAM 202 shown in FIG. 2 .", "The memory map shows a state in which the RAM 202 is loaded with the network printer control program unloaded from the FD 204 so that the program can be executed.", "According to the present embodiment, although an example in which the RAM 202 is loaded with the network printer control program and the associated data from the FD 204 so as to execute the program and data, the RAM 202 may be loaded with the network printer control program from the HD 205 in which the network printer program is already installed every time the network printer control program is operated from the FD 204 , with the exception of the above example.", "As media for storing the network printer control program, there may be exemplified the CD-ROM, the CD-R, the PC card, the DVD, the IC memory card except the FD.", "Further, the network printer control program may be stored in the ROM 21 .", "Then, the network printer control program is configured to form a part of the memory map so that it can be directly executed by the CPU 200 .", "Further, the network printer control program may be simply called a print control program.", "In the clients, the print control program includes programs for performing controls of designating grouping jobs as print jobs which are designated to be grouped and instructing a printer to be changed.", "In the print server, the print control program includes programs for controlling the order of the grouping jobs, managing the spools of all the print jobs in the grouping jobs and noticing the end of print of the grouping jobs or a request for change of a printer, etc.", "The print control program of the present invention for carrying out the above mentioned controls may be separately divided into a module installed in the clients and a module installed in the print serve.", "An execution part may be selected so that the print control program is installed by installing it once and it functions for the clients or for the print server depending on an environment where the print control program is executed.", "The print control program according to the present embodiment includes both the functions.", "Reference numeral 301 denotes a basic I/O program which is an area where a program with an IPL (initial program loading) function or the like for reading the OS to the RAM 202 from the HD 205 and starting the operation of the OS when the power of the controller is included.", "Reference numeral 302 denotes an operating system (OS).", "303 designates the network printer control program and stored in an area ensured on the RAM 202 .", "304 denotes the associated data and stored in an area ensured on the RAM 202 .", "305 denotes a work area and an area for executing the printer control program by the CPU 200 is ensured therefor.", "FIG. 4 is a diagram showing one example of the memory map of the FD 204 shown in FIG. 2 .", "In FIG. 4, reference numeral 400 denotes the contents of the data of the FD 204 .", "401 denotes volume information showing the information of the data.", "402 denotes directory information.", "403 designates the network printer control program as the print control program which s described in the present embodiment.", "404 denotes the associated data thereof.", "The network printer control program 403 is programmed on the basis of a flowchart described in the present embodiment.", "According to the present embodiment, the configuration of the client is the same as that of the server.", "FIG. 5 is a view illustrating the relation between the FD 204 and the FD drive 203 shown in FIG. 2 into which the FD 204 is inserted.", "In FIG. 5, the parts the same as those shown in FIG. 2 are designated by the same reference numerals.", "In the FD 204 , the network printer control program described in the present embodiment and the related data are stored.", "FIG. 6 is a block diagram for explaining the configuration of the print control module of the information processor according to the present invention.", "Components the same as those shown in FIG. 1 are designated by the same reference numerals.", "Referring to FIG. 6, reference numeral 600 denotes a client machine in which a client module corresponding to the network printer control program as the print control program for executing a procedure shown in a flowchart described below.", "In the same figure, reference numeral 601 denotes an application software for creating documents or tables and outputs graphic drawing data to a graphic engine 602 upon displaying or printing.", "The graphic engine 602 is graphic drawing means provided by the OS, which indicates a GDI in the OS of Windows (registered trademark of Microsoft Corporation, in U.S.A.).", "The graphic engine 602 converts a GDI (Graphic Device Interface) function as the graphic drawing data outputted from the application 601 into a DDI (Device Driver Interface) function as graphic drawing data which can be interpreted by a printer driver 603 and outputs the DDI function to the printer driver 603 upon printing process.", "The printer driver 603 converts the DDI function into the print data including a PDL (Page Description Language) which can be interpreted by the printer on the basis of the DDI function received from the graphic engine 602 and outputs the print data as the print job with a JL (Job Language) added to a Windows Spooler 604 as a spooler provided by the OS.", "Further, the application 601 shifts its processing to the printer driver 603 upon set-up of printing.", "The printer driver 603 displays a graphical user interface screen on the display 207 as the display part to make a user perform various kinds of printing set-up.", "The spooler 604 of the OS sequentially delivers the print jobs received from the printer driver to a client spooler 606 .", "A client manager 605 monitors the client spooler 606 .", "When the spooler 606 begins to spool the print job, the client manager decides the set-up of the print job to extract jog information from the print job, in the case of the client spooler, to issue a print request to a print server 610 and to make a client spooler 606 spool the print job.", "On the other hand, in the case of a server spool, the client manager supplies the print job spooled in the client spooler 606 to the print server 610 as a print request to finish a print processing as the client.", "Further, when the client manager 605 receives a transmit permission notice of the print job from the print server 610 , the client manager begins to transmit the print job spooled on the client spooler 606 directly to a network printer.", "At this time, the print job spooled in the client spooler is not deleted but held.", "When the client manager 605 receives a print completion notice from the print server 610 , client manager can delete the spooled print job.", "Reference numeral 610 denotes a machine in which a print server module corresponding to the network printer control program as the print control program for executing a procedure shown in a flowchart described below.", "611 denotes a server manager which receives a print request from each client through the network 106 .", "In the case where the print request is the print job including the print data, the print job is spooled in a server spooler 612 and the job information receiving the print request is managed in a job management table 613 .", "On the other hand, in the case when the print request is the job information including no print data, the job management table is updated on the basis of the job information.", "Further, the server manager 611 monitors the processing state of the job in each network printer, updates the job management table 613 every time the output of the print job is completed, and starts the transmission of subsequent print jobs.", "At this time, when the print jobs to be transmitted are spooled in the server spooler 612 , the print server 610 transmit them as they are.", "However, when the print jobs to be transmitted are spooled by the client spooler 606 , the transmit permission notice of the print jobs is supplied to its client.", "Further, the job management 613 (job managing means) has a print queue 615 for controlling a print order on the basis of the job information received from the client and managing an order for sequentially supplying the transmit permissions of the print jobs and a group job management table 616 for managing as to whether or not the information of all the print jobs in a group job is prepared.", "Reference numerals 105 and 650 denote network printers.", "In this connection, the above described classification is made depending on depending on the functions of respective devices.", "If both softwares are provided on the same information processors (machines), in other words, if the print server which the client asks to print is provided on the same machine, a communication between processes on the same machines can be executed without employing the network.", "A different machine operates as one client.", "Further, the spooler of the OS may internally include similar functions to these functions.", "FIG. 7 is a diagram showing one example of the data structure of the job information generated in the client and managed by the print server, as described with reference to FIG. 6 .", "This job information is information which shows the type of the print job created by the client manager 605 on the basis of the print job generated by the printer driver 603 of the client and is transmitted to the print server 610 as the print request.", "As shown in FIG. 7, the job information according to the present embodiment comprises a job ID for identifying the print job to the client from the print server, a printer name for designating a device to which the print job is outputted, a machine name as the host name of the client, the status of the print job, a document name extracted from the original document of the print job (generally, a document name designated in an application), the data size of the print job, a spool method for designating as to whether the print job is spooled by using the client spooler or by using the server spooler (0 or 1 bit expression may be utilized), a permission/inhibition of group print indicating as to whether or not the print job is grouped and controlled as a grouping job, a group name when the print job is grouped and printed as the grouping job, a print order in a group when the print job is grouped and printed, the number of jobs in a group showing the total number of print jobs included in the group when the print job is grouped and printed, etc.", "FIG. 8 is a diagram showing one example of group designating information managed by the client 600 shown in FIG. 6 .", "In the present embodiment, the group designating information is created when the client manager 605 receives the print job, as described below.", "Further, the group designating information may be generated by the printer driver on the basis of a value designated by a user in accordance with a user interface screen provided by the printer driver when a print step is designated from the application.", "As shown in FIG. 8, the group designating information in the present embodiment comprises a client name as the host name of the client, a group name (ID) showing a group name when the print job is grouped and printed, a print order in a group when the print job is grouped and printed, the total number of jobs in a group, etc.", "FIG. 9 is a sequence diagram of the present invention showing an example of a procedure for grouping and printing the print jobs received from the three clients.", "Initially, referring to FIG. 9, the procedures of the clients and the server in the group print according to the present invention will be described.", "In FIG. 9, the clients PC 1 , PC 2 , and PC 3 spool respective print jobs (print job 1 , print job 2 , and print job 3 ) in the client spoolers.", "Further, each client informs the print server of the job information.", "The print server groups the print jobs on the basis of the print information and prints them in accordance with a print order designated by each client, for example, an order of the print job 3 , the print job 2 and the print job 1 .", "Initially, the print job to be grouped and printed is generated and a client spooling step is carried out from the client PC 1 .", "In the case where the group job is first generated, the group designating information shown in FIG. 8 and the job information shown in FIG. 7 are generated simultaneously with the formation of the print job.", "The client PC 1 instructs the print server to perform a group print by using the group designating information and the job information.", "At this time, the print server generates the group information on the basis of the received group designating information and the job information, adds a new group job to the above described group job management table and manages it.", "The group job management table has cells of the total number of jobs in the group job and a state of “waiting for print”", "after receiving the job information is written in a proper cell on the basis of the information of the print order in the group included in the job information received from each client and the cell is updated.", "The server manager 611 monitors the group job management table 616 in the job management table 613 to decide whether or not all the status of cells with the total number of jobs of a group name of ION becomes a state of “waiting for print.”", "More specifically, when the server manager 611 decides that all the print jobs in the same group become a state of “waiting for print”, in other words, they are spooled by the clients or the server, it supplies a print request to a print queue for a printer to which the information is outputted and begins to control an order relative to other print jobs in order to start the printing step of the group job.", "Next, the job information (a group name is designated) shown in FIG. 7 is inputted to the print server from the client PC 3 and the client PC 2 and the group management table is respectively updated so that a print request is supplied to the print queue as mentioned above.", "In this case, the print order in the group is set to a sequence of the clients 1 , 2 and 3 .", "However, a timing at which the job information is supplied to the print server or a timing at which the job information is spooled in each spooler may be arbitrarily set, because the print order in the group is determined in the job information of each print job.", "When the client PC 1 shown in FIG. 9 starts the printing step of the print job to be grouped by the printer driver, the print job is spooled once in the spooler 604 of Windows, and then, the print job spooled similarly to an ordinary printing for the OS is outputted.", "The client manager 605 catches the outputted print job and spools it in the client spooler 606 .", "Then, the client manager decides the set-up of the print job and generates the job information while the client manager 605 spools the print job in the client spooler 606 and supplies it to the print server 610 as a print request, in the case of the client spool.", "Further, the job information may be generated by the printer driver 603 .", "On the other hand, in the case of the server spool, the client manager 605 supplies the print job spooled in the client spooler 606 to the print server 610 as the print request to spool the print job in the server spooler 612 of the print server.", "FIG. 10 is a flowchart showing one example of a first data processing procedure in the information processor according to the present invention, which corresponds to the spool processing procedure by the client 601 shown in FIG. 6 .", "Here, s 1001 to s 1006 designate respective steps.", "In the client 600 , when the application 601 starts a printing process, a user sets a printing step by employing a graphical user interface (see FIG. 19) for setting the printing step provided by the printer driver in step s 1001 .", "The printer driver 603 provides a graphical user interface screen for setting the print step and displays it on the display 207 through the OS.", "Referring to FIG. 19, 1901 denotes a menu capable of setting the types of print job.", "In “print”", "of the menu, a print job is generated for an ordinary printing process, and the print job is transmitted to the print server or the printer together with a print request.", "On the other hand, in “group print”", "in the menu, a print job is generated as a group print job (also called a grouping job.", "This print job is not spooled in the print server or the client.", "The job information is outputted to the print server.", "After print set-up values are set by the user, the application 601 begins to output the graphic drawing data to the graphic engine 602 , that is to say, starts a printing process.", "Thus, as mentioned above, the graphic engine receives the GDI function as the graphic drawing data, converts the GDI function into the DDI function and delivers it to the printer driver 603 .", "The printer driver 603 generates print data described by a page describing language on the basis of the received DDI function and supplies the print job to the Windows spooler 604 .", "The Windows spooler 604 outputs the received print job to the client manager 605 .", "When the client manager 605 starts a spool processing for the client spooler 606 of the print job received from the Windows spooler 604 , the client manager 605 obtains the job ID from the server manager 611 of the print server 610 and generates job information as shown in FIG. 7, for instance, JOB-INFO-2 of Windows.", "The job information except the “job ID”", "can be created on the basis of information in the client.", "For instance, the “printer name”", "may be the name or the path of a printer designated in a device to which the job information is outputted.", "As for the “document name,” the name of a document may be got from the application 601 .", "Further, the “permission/inhibition of group print”", "can be generated by judging whether the menu 1901 is set to the “group print”", "or the “print,” as mentioned above.", "Further, in the “spool method,” is generated information indicating that whether or not the check box of the server spooler in a spool method 1902 shown in FIG. 19 is checked, and, the server spooler is used when the check box is checked, and the client spooler is used when it is not checked.", "A communication method between the client and the server may depend on, for instance, a multiprotocol function such as RPC or a processing utilizing the communication function of Winsock or Win 32API and may not depend on a specific communication method.", "In step s 1002 , the client manager 605 decides whether or not this job is the job of the group print or an ordinary job by setting up the print step of the print job or viewing the “permission/inhibition of group print”", "of the generated job information.", "Further, while the “permission/inhibition of group print”", "is designated by a user upon instruction of a print by employing the graphical user interface for setting the print step of the printer driver, and then, the print is instructed, the display of the graphical user interface screen may be carried out by displaying a DLL registered as the port monitor of the Windows spooler 604 or a dialog in the client, every time data is supplied to the port as a contact for the Windows spooler 604 , or designating the screen as a port exclusively used for a group print for each port.", "For instance, the group printing may be automatically carried out on the basis of information capable of specifying the print job to be grouped by the printing system according to the invention, such as a prescribed document name employed by the application or an ID allocated uniquely by the Windows spooler 604 , etc.", "The above designation is different from an ordinary job only in respect of a point that designating information related to the group print is added to the job information of each job, so that this designation can be registered as a set-up for each port on the client.", "However, a special set-up is not needed for setting the printer or the printer server as common resources to other clients.", "When it is decided that the above job is the print job for a group printing in accordance with the decision in the step s 1002 , the client manager 605 supplies a dialog box for receiving a designation from a user shown in FIG. 17 to the OS and displays the dialog box on the display 207 .", "The dialog box shown in FIG. 17 can designate a group name (or ID) for designating the group print, the total number of jobs in the group and the print order as shown in FIG. 8 .", "The user designates the group name and the print order by using the keyboard 206 or a mouse, etc.", "As for a method for designating the group printing, since the group designating information may be designated for each job, any method for uniquely specifying the contents of the group designating information relative to information (document name, job ID, etc.) capable of a job may be possibly employed.", "Further, the designated values possessed by the client such as a registry or an INI file may be employed without display of the dialog box and a manual input, or a plurality of information may be held so that the user can select it.", "Next, in step s 1004 , the client manager 605 decides whether the grouping job is a new grouping job or a grouping job already registered in the print server 610 on the basis of the group name inputted by the user relative to the dialog of FIG. 17 displayed in step s 1003 .", "In other words, upon designation of the group name shown in FIG. 17, when a new name is inputted by the user, the client manager decides that it is a new grouping job.", "When a “reference button”", "1701 is pushed to refer to the group name of the grouping job registered in the print server 610 , the client manager decides that the grouping job is the already registered group print.", "When it is decided that the grouping job is a new group print, the print manager shifts the process to step s 1005 .", "In the step s 1005 , the client manager 605 urges the user to manually input the information of a print order in the new group job and the total number of print jobs in the new group job.", "Further, the client manager 605 adds group print designating information including a group name, a print order in the group and the number of jobs in the group to the job information shown in FIG. 7 .", "In step s 1006 , the client manager 605 adds information including a group name (or ID), a print order, the total number of jobs, etc, for designating the group print shown in FIG. 8 to the job information of the print job, on the basis of the input of the dialog box.", "The present invention is described on the assumption that members for the group print are included in the job information.", "However, for instance, information capable of discriminating the group print is embedded in comment information or a document name so that the present embodiment can be realized without preparing special members (for instance, a character line such as Group 01-1-5 is added to a comment or a document name).", "Then, in step s 1007 , the client manager 605 performs a spool processing of the print job.", "The spool processing is performed in such a manner as described below.", "First, the client manager 605 views the “spool method”", "of the job information to decide whether the print job is the print job of the client spool or the print job of the server spool.", "When the client manager decides that it is the client spool, the client manager 605 spools the print job received from the Windows spooler 604 in the client spooler 606 so as to coordinate with the group designating information, and transmits the job information (see FIG. 7) and the group designating information (see FIG. 8) to the print server 610 .", "On the other hand, when the client manager decides that it is the print job of the server spool, the server manager 605 sends the print job, the job information and the group designating information to the print server 610 to open the printing step in the client 600 .", "Next, the spool procedure of the clients 2 and 3 , that is to say, a procedure for adding remaining print jobs to a proper grouping job will be described after the grouping job is set up.", "A procedure from steps s 1001 to s 1003 is the same as that of the above processing, and accordingly, the explanation thereof will be omitted.", "In step s 1004 , the client manager 605 decides whether the grouping job is a new grouping job or a grouping job already registered in the print server 610 on the basis of the group name inputted by the user for the dialog in FIG. 17 displayed in the step s 1003 .", "In the dialog shown in FIG. 17, when the “reference button”", "1701 is pressed in accordance with the instruction of the user to refer to the group name of the grouping job registered in the print server 610 , the client manager decides that it is the registered group print and advances the process to step s 1009 .", "In the step s 1009 , the client manager 605 asks the server manager 611 of the print server 610 about the list of the grouping jobs spooled in the print server 610 .", "This inquiry means may be an ordinary communication between processes such as the RPC processing of API, for instance, the Enumjobs of Win 32API.", "For this inquiry, in the print server 610 , there will be carried out processings as mentioned below.", "Initially, when the server manager 611 receives the inquiry of the list of the grouping jobs from the client manager 605 , the server manager 611 refers to the group job management table 616 managed in the job management table 613 to generate the list of the grouping jobs to respond to the client manager 605 .", "Then, the server manager 611 returns the generated list to the client manager 650 .", "Further, in the cases other than the inquiry, various kinds of spool processings are carried out.", "When a print request including the job information is received from the client, the server manager 611 recognizes the print request and controls the job management table 613 to manage a print order.", "At this time, when the job management table 613 analyzes the job information to decide that the print request is the group print job, the job management table 613 updates the group job management table 616 so as to indicate that the job of a relevant print order is spooled in a new job or the already registered grouping job.", "At the same time, the server manager 611 spools the print job in the server spooler 612 .", "In the case where the spool method is the client spool, only the job information is managed and the spool processing is left to the client.", "In the step s 1009 , the client manager 605 acquires the list of the grouping jobs from the server manager 611 in accordance with the above inquiry, generates data for display and displays it on the display 207 through the OS as shown in FIG. 18 .", "FIG. 18 shows one example of a display screen formed by the client manager on the basis of the list of the grouping jobs managed by the group job management table.", "Reference numeral 1801 denotes the name of the grouping job managed by the print server 610 .", "1803 denotes a print order in each group with the total number of jobs and the print order displayed.", "1803 denotes the status of a print job.", "A notice of “waiting for print”", "indicates that the print job is already spooled.", "A notice of “not processed”", "indicates that a print job corresponding to a relevant print order has not been spooled yet.", "1804 denotes a spool method.", "A “client”", "indicates the print job including print data is spooled in the client spooler 606 .", "A “server”", "indicates that the print job including print data is spooled in the server spooler 612 .", "1805 denotes the name of a client who performs the print request of a corresponding print job.", "In the graphical user interface, the user can determine a selection state for each print job by using a pointing device such as the keyboard 206 or a mouse.", "In the example of FIG. 18, a second print job in the print order of a Group 2 located in a range shown in 1806 is selected.", "When an OK button 1807 is designated under this selected state, each item of the dialog for designating the group print illustrated in FIG. 17 is automatically selected.", "For instance, when the OK button 1807 is designated while the range of 1806 is selected, “Group 2”", "is inputted as the group name shown in FIG. 17, and “2/5”", "is automatically inputted as the print order.", "When the print job is designated by the user as shown in FIG. 18 in such a manner, the client manager 605 decides the group name of the designated print job in step s 1010 , and inputs the decided group name to the item of the group name.", "Subsequently, in step s 1011 , when the print job is designated by the user as shown in FIG. 18, the client manager 605 decides the print order and the total number of jobs of the print job and inputs them to the respective items.", "As described above, according to the present embodiment, the user designates the print job in the grouping job by using the graphical user interface screen so as to automatically input the respective items.", "The present invention is not limited thereto.", "For instance, the client manager 605 may get only the group name of the grouping job from the print server 610 to designate the grouping job therefrom, and then, the user may manually input the print order or the like.", "When various designations in the group print job are set, the procedure advances to a processing of step s 1006 .", "Steps after the step s 1006 are the same as those described above, and accordingly, the explanation thereof will be omitted.", "FIG. 16 is a diagram showing one example of the data structure of group print information created by the server manager 611 of the print server 610 shown in FIG. 6 .", "This group print information is formed on the basis of the job information and the group designating information received from the client.", "As illustrated in FIG. 16, according to the present embodiment, group names, the total number of jobs, printer names, printer status and job IDs, print orders, status and client names are included so that the number of them correspond to the number of jobs.", "Now, by referring to a flowchart shown in FIG. 11, there will be described a spool processing by the server manager 611 operating on the print server 610 shown in FIG. 6 .", "FIG. 11 is a flowchart showing a second data processing procedure in the information processor according to the present invention, which corresponds to the spool processing by the server manager 611 operating on the print server 610 shown in FIG. 6 .", "Here, s 1101 to s 1112 denote respective steps.", "In the step s 1101 , when the spool processing of a job from the client 600 is started, the server manager 611 generates a job ID and delivers the job ID to the client manager to perform a spool processing mentioned below in step s 1102 .", "In the step s 1102 , the server manager 611 receives job information and a print request from the client manager 606 .", "Further, the server manager 611 also receives group designating information from the client manager 606 as required.", "When the server manager 611 receives the print request, the server manager 611 updates a print queue in order to start the management of the print order as a result of receiving a new job in the print queue in the job management table 613 , and spools the print job received from the client in the server spooler 612 .", "When the server manager 611 does not receive the print job from the client, in other words, in the case of the print job subjected to the client spool processing, the client spools the print job, and the print server 610 manages the print order.", "Subsequently, in step s 1103 , the server manager 611 searches the job information delivered from the client manager 606 .", "Then, in step s 1104 , the server manager 611 decides whether or not the print job is a grouping job as a print job in which a group print is designated depending on the presence or absence of group print designating information in the job information.", "When the print job is the print job with a group print designation, proessings are different between the spool of the first job and the spool of a second job and jobs after that in the same group as described below.", "In step s 1105 , the server manager 611 decides whether or not the received print job is a new group print job on the basis of the job information and the group designating information.", "When it is decided that the print job is the new group print job, the procedure advances to step s 1106 .", "Otherwise, in other words, if group print information (GP-INFO) shown in FIG. 16 is already generated on a storage device, the processing advances to step s 1107 .", "In the step s 1106 , the server manager 611 generates the group print information (GP-INFO) and stores the new group print information in the group job management table 616 of the job management table 613 .", "This group print information GP-INFO is managed on the basis of list data for each printer in which the print step is designated.", "Then, in the step s 1107 , the server manager 611 records information peculiar to the job such as the printed client name (or address) or the print order in the group, etc.", "to the generated group print information (GP-INFO) from the job information.", "Next, in step s 1108 , the server manager 611 decides whether or not the print job is a first job in the print order in the same group.", "In this case, when the print job is the first job, the spool order of the job corresponds to the print order in the group.", "Therefore, the procedure advances to step s 1110 to finish the spool processing without changing the position of the job.", "Then, in the decision of the step s 1108 , when it is decided that the print job is not the first print job in view of the print order, the procedure moves to step s 1109 to arrange the job information of the print job so as to correspond to the sequence designated in the same group and to arrange the spool order of the print job in the server spooler 612 as required.", "Now, the spool order of the print jobs will be described below.", "This processing is carried out at the time of a spool processing of the print job of the server spool.", "More specifically, any job before the print job in the print order which is being processed, among jobs already spooled in the group print information (GP-INFO) moves just after that job.", "If only jobs after the print job in the print order which is being processed are spooled, that job will move so as to come to the first, and the procedure moves to step s 1110 to finish the spool processing.", "The print jobs are spooled in accordance with the print order as described above, so that the print jobs can be easily read upon print of the grouping job.", "However, even when the spool order of the print jobs does not correspond to the print order of the print jobs, the print processing of the jobs can be actually performed.", "On the other hand, in the step s 1104 , when it is decided that the spool is equal to a spool of the print job which is not the group print job, the procedure moves to step s 1111 .", "In the step s 1111 , the server manager 611 recognizes whether or not a present spool position interrupts jobs printed in accordance with the group print designation.", "If the server manager decides that the spool position of the print job interrupts the jobs with the group print designation in the same group to designate the change of another order such as a priority (in the case of YES), the server manager decides whether or not the jobs before and behind that spool position are of group print designation from the job information.", "In step s 1112 , the spool position is changed so as to spool the job behind the former position.", "In the step s 1111 , if an ordinary spool position does not interrupt the group print jobs, the procedure directly advances to step s 1110 to finish the spool processing.", "As for the print processing of the spooled print job, there will be described the processing of the server manager 611 of the print server 610 by referring to a flowchart shown in FIG. 12 .", "FIG. 12 is a flowchart showing.", "one example of a third data processing procedure in the information processor according to the present invention and corresponds to that of the server manager 611 in the print server 610 shown in FIG. 6 .", "This procedure is executed for a process unit like the thread of Windows in such a way that the server manager 611 monitors the status of a printer under the control connected to the network, manages spooled jobs, and successively starts the transmissions of the print jobs to proper printers.", "s 1201 to s 1208 denote respective steps.", "First, in step s 1201 , the server manager 611 monitors the status of the printer under the control.", "When the server manager decides that the print job can be transmitted to the monitored printer, this process is started.", "Then, in step s 1202 , the server manager 611 searches job information spooled in the job management table 613 .", "Then, in step s 1203 , the server manager decides whether or not the print job waiting for print is present among the print jobs to be transmitted to the proper printer in the job management table 613 .", "When this state is a steady state and there is no print job waiting for print, the server manager stays in the step s 1201 to continuously wait for a job to be spooled until it is decided that the job waiting for print exists in the step s 1203 .", "On the other hand, in the step s 1203 , when it is decided that there is a job waiting for print, the server manager 611 decides whether or not the print job waiting for print belongs to a group print.", "If the print jobs are arranged in the print order of group print designation, the server manager 611 analyzes the group job management table 616 in step s 1205 so that it decides whether or not all print jobs in the same group are spooled.", "In this case, when the server manager decides that all the print jobs in the group are spooled, the server manager 611 carries out the print processing of the grouping job in step s 1206 .", "Specifically, the server manager 611 ,transmits the print jobs sequentially spooled in accordance with the print order in the group to the printer.", "In this transmit processing, the server manager 611 recognizes the spool method of the print job in the print order, reads out the proper print job stored in the server spooler 612 in the case of the server spool, and transmits the print job to the printer through the network.", "Further, in the case of the client spool, the server manager 611 recognizes the client 1805 shown in FIG. 18 and supplies print transmit permission information including information for designating the job ID to the relevant client.", "When the transmit processing of print data to the printer 105 from the print server 610 or the client 600 is completed, the server manager 611 changes the status information of the group print information (GP-INFO) managed in the group job management table 616 and the group management table 610 shown in FIG. 6 to “end of transmission”", "to shift to a processing of the print job corresponding to a next print order.", "The jobs of the same group are continuously transmitted to the printer 105 to perform a print process by repeating the print procedure.", "On the other hand, in the step s 1205 , when it is decided that the print order of the first job of the same group is obtained before all the jobs in the same group are spooled so that all the print jobs of the same group are not spooled, the procedure advances to step s 1208 .", "The server manager 611 shifts its control to a next print job in the print queue for the relevant printer and returns to the step s 1203 to continue to process the next job similarly.", "In the step s 1204 , in the case where it is decided that the print job of the print order in the print queue 615 is an ordinary print job, the procedure directly moves to step s 1206 so that the server manager 611 performs the print processing (transmission control of the print job) as described above.", "The print processing is carried out in the print server 610 accordance with the above procedure.", "If the print is not recognized, after the transfer of data is completed, the group print information GP-INFO is deleted when the job is deleted.", "These procedures are performed, so that even when a plurality of series of print jobs printed at arbitrary timing by a plurality host computers are spooled in the print server under a state in which ordinary jobs mixed, or spooled in the client, they can be continuously printed together in regular order designated for the same printer.", "[Second Embodiment] Now, a second embodiment of the present invention will be described below.", "After the print jobs are printed in accordance with the procedure described in the first embodiment, the server manager 611 of the print server 610 may recognize the print state of each print similarly to the ordinary print job from the printer 105 , record it in the group print information and inform the client manager 605 of the client 600 in which the respective jobs are spooled of the end of print after recognizing the end of printing processes of all the print jobs in the group print information.", "The above matter will be described in the second embodiment.", "FIG. 13 is a flowchart showing one example of a fourth data processing procedure in the information processor according to the second embodiment of the present invention, which corresponds to a print recognition thread (detailed procedure of print recognition process) by the server manager 611 shown in FIG. 6 .", "Steps s 1301 to s 1312 denote respective steps.", "Initially, in step s 1301 , the print recognition thread is started.", "This thread may be started upon start of the server manager 611 and.", "stay until the power of the server machine 610 falls, or may be started only during a period after the print processing until the print recognition is obtained and the operation of the thread is finished at an arbitrary timing.", "Then, after the start of the thread, in step s 1302 , the server manager 611 monitors the status of the printer under control through the network to wait for the notice of print recognition from the printer 105 .", "In this recognition method, for instance, in the case of the network printer under the network environment of TCP/IP, the print server may carry out a polling using a command such as get of SNMP, or may receive a notice from the printer 105 by a trap or the like.", "Further, in the case the printer is connected to a local places, a communication through a center-cable may be employed and any protocol or any method for obtaining information may be utilized.", "In such a manner, when the notice of print recognition is sent to the server manager from the printer 105 , in step s 1303 , the server manager 611 decides whether or not a notice of error of the print job is sent from the printer 105 .", "When the server manager 611 decides that the notice of error is sent, the procedure moves to step s 1312 .", "Then, the server manager 611 recognizes the client of the related print job by using the group job management table shown in FIG. 18 and gives notice of an error to the client manager 605 of the relevant client 600 .", "On the other hand, in the step s 1303 , when the server manager decides that the notice of error is not sent from the printer, in step s 1304 , the server manager 611 decides whether or not the print job is the group print job from the job information of the print job in which the end of print is recognized.", "When the server manager decides that the print job is the job of group print, the server manager updates the status of the relevant print job in the group job information (GP-INFO) from “during printing”", "to “end of printing”", "in step s 1305 .", "Then, in step s 1306 , the server manager 611 decides whether the end of printing of all the print jobs in the group print job information (GP-INFO).", "When the server manager decides that there remain jobs which are being printed, the manager returns the process to the step s 1302 to wait for a notice of print recognition from the printer 105 .", "On the other hand, in the step s 1306 , when the server manager decides that a notice of print recognition of the last job in the group is sent from the printer, the server manager 611 shifts the process to step s 1307 to give notice to the client manager 605 of the client 600 supplying the print request for the print job in the group.", "After the server manager gives notice to each of the clients, the server manager 611 deletes all job information of the same group instep s 1308 .", "When the print job including print data remains in the server spooler 612 even after the print processing, the server manager 611 delete the print data as well as the job information.", "After the job information in the group is deleted in such a way, in the step s 1309 , the server manager 611 deletes the group print information whose print is finished and returns to the step s 1302 .", "On the other hand, in the step s 1304 , when a notice of print recognition of an ordinary job is sent from the printer, the server manager 611 gives notice to the client 601 of each client machine in step s 1310 , deletes the job in step s 1311 and returns to the step s 1302 .", "According to the above described procedure, the print recognition of the group print can be also done by hardly adding an excess processing to the procedure for recognizing the printing process of the ordinary job.", "Therefore, even when only the print recognition of each job can be obtained from the printer 105 , it can be recognized that the printed jobs are printed and discharged together, and a notice that the jobs are printed together can be given to a host computer supplying a print request for each print job.", "[Third Embodiment] According to the second embodiment, it is recognized that the print jobs for which the print requests are sent are printed and the printed jobs are discharged together and the notice that the print jobs are printed together is sent to the client (host computer) issuing the print request for each print job.", "However, any error may be possibly generated in the printer 105 during the printing process.", "In the case where an error is generated in the printer before the print jobs to which the print requests are issued are printed and the printed jobs are delivered together, a configuration may be used in which the destination where printing is performed is changed together to another printer on the network.", "Now, a third embodiment of the present invention will be described hereinafter.", "FIG. 14 is a flowchart showing an example of a fifth data processing procedure in the information processor showing the third embodiment of the present invention, which corresponds to the procedure for changing the printer to another printer by the server manager 611 in the print server 610 .", "Steps s 1401 to s 1414 denote respective steps.", "Further, in the third embodiment, the printing process is performed in accordance with the procedure of the first embodiment, and a process will be described after the print server is brought into a state in which the print server waits for print in accordance with the procedure of the second embodiment.", "First, in step s 1401 , when a process of print recognition is started, the server manager 611 is put to a state in which the server manager 611 acquires the status of the printer 105 or the print job on the basis of the notice from the printer 105 , or is waiting for receiving a notice from the client 601 .", "Next, in the step s 1402 , when a notice of the error of the print job is sent to the server manager 611 from the printer 105 , the server manager 611 decides whether or not the error corresponds to the error of the job after the transfer of data in step s 1403 .", "In this decision, the status of each job may be obtained directly from the printer 105 .", "When the error of the printer 105 is generated before the print recognition is not got, this may be judged as the error of the job.", "When the normal completion of the job cannot be recognized, it may be judged as the error of the job.", "In the step s 1403 , when it is decided that the error of the print job is an error after the transfer of data to the printer 105 , the server manager 611 searches the job information from a notified job ID to decide whether or not the print job is the group print job on the basis of the job information.", "Here, when it is decided that the print job is not the print job of the group print, the server manager 611 sets the status of the print job to “error”", "in step s 1405 , gives a notice that the job is printed to the client manager 605 of the client 600 in step s 1406 and returns to the step s 1402 to wait for a next recognition.", "On the other hand, in the step 1404 , when it is decided that the print job is the group print job, the server manager 611 updates the group print information (GP-INFO) in step s 1407 to judge the status of the print job of the group print information (GP-INFO) as an error.", "Next, in step s 1408 , the server manager 611 decides whether or not the substitute of the printer is designated upon error of the printer.", "This decision process is carried out after the client points out the error upon generation of the error, as described below.", "The information of a substitute printer name is previously added to the group designating information shown in FIG. 8 and the substitute printer name is managed in the group print information (GP-INFO) shown in FIG. 16 so that the server manager 611 can decide it.", "Here, when it is decided that the substitute printer for the currently employed printer is not designated, the server manager 611 only changes the status of the print job in the steps s 1405 and s 1406 similarly to the ordinary job, and then, gives a notice to the client manager 605 of the client 600 .", "In this case, the change of the printer is not executed until an instruction is sent to the server manager from the client manager 605 of the client 600 .", "On the other hand, in the step s 1408 , when the substitute printer for the printer is designated upon generation of an error, the procedure advances to step s 1409 , and the server manager 611 shifts all the job information in the group to the list data of a substitute printer, for instance, a printer 650 .", "Further, the management of the group print information (GP-INFO) is also shifted to the group print information list of the new printer.", "In this case, after the print server 611 changes the automatically spooling printer, in step s 1410 , the server manager 611 gives a notice of the change of a printer to the client of the client machine, After the printer is changed to another printer, the print jobs are printed as the jobs of the group print in a similar manner to that of the first embodiment.", "On the other hand, when an instruction is supplied so to change the printer to a substitute printer after steps 1402 and s 1403 shift to step s 1411 shown in FIG. 14, the server manager 611 decides whether or not the print job of the substitute printer designated by the client is the group print job in step s 1412 on the basis of the job information.", "When the print job is not the job of group print, the server manager 611 moves only the designated print job in step s 1413 .", "When the print job is the job of group print, the server manager updates group print information (GP-INFO) in step s 1414 , shifts to the steps s 1409 and s 1410 .", "The server manager 611 changes the output part of all the print jobs in the group to the substitute printer and spools the job information of the print jobs in the print queue in the relevant printer.", "The substitute printer may be designated on the basis of a registry, an INI file and information for managing the printers by the print server or the printers having the same printer driver may be selected at random.", "Accordingly, any method for designating the printer which can normally print created documents can be utilized.", "Now, there will be described a processing when the printer of the job is changed to other intended printers in accordance with the instruction of the user of the client 600 after the print recognition from the print server 610 is notified upon generation of the error.", "FIG. 15 is a flowchart showing one example of a sixth data processing procedure in the information processor showing the third embodiment of the present invention, which corresponds to the procedure of print recognition of the client manager 605 and the procedure for changing the printer of the group print in the client manager 605 (a printer change procedure after notification of the error of the job).", "s 1501 to s 1511 denote respective steps.", "First, in step s 1501 , the above described process is started upon start of the client manager 605 or after the print processing, the client manager 605 is waiting for an instruction in step s 1502 .", "When any instruction is sent to the client manager 605 from the server manager 611 , in step s 1503 , the client manager 605 decides whether or not the instruction is the notification of print recognition in other words, the print confirmation.", "Whether or not the printer is changed to the substitute printer, the print confirmation is similarly carried out.", "In step s 1503 , when it is decided that the print confirmation is supplied to the client manager, in step s 1504 , the client manager 605 provides, for example, the graphical user interface screen showing the change of the status or the like such as the dialog box or the print manager print manager and displays the print confirmation or notification on the display 207 through the OS to give a notice to the user.", "Then, the procedure returns to the step s 1502 after the confirmation.", "In case of the group print, after the confirmation process to the client is finished, the job information is deleted.", "Therefore, for this display process, a special display for indicating that the print confirmation of the group print is completed may be done by obtaining the job information or the group print information from the server manager 611 of the print server 610 .", "On the other hand, in step s 1503 , when it is decided that the notice is not the print confirmation, the client manager 605 decides in step s 1505 whether or not the notice is an error notice.", "When the client manager 605 decides that the notice is the error notice, the procedure advances to step s 1506 .", "The client manager 605 provides a dialog showing the error of a job to display it on the display 207 through the OS and notify the user of the error.", "In this display, the client manager 605 may give a notice to the user as the change of the status of the print job like the print manager of Windows without displaying a special notice message.", "Then, after the notice of an error is displayed, in step s 1507 , the client manager 605 provides a user interface (UI) for changing the printer such as the dialog box of Windows and displays the notice on the display 207 shown in FIG. 2 .", "Next, in step s 1508 , the client manager 605 decides whether or not the printer of the job is instructed to be changed in accordance with the instruction of the user.", "When the client manager 605 decides that the printer of the job is instructed to be changed to a substitute, the procedure advances to step s 1509 .", "The client manager 605 notifies the server manager 611 of the server 610 of the substitute printer to return to the step s 1502 .", "Even in the case of the job, only the substitute printer may be designated relative to the print job whose printer is to be changed.", "Further, when the printer is changed to a substitute by the server manager 611 , a notice of change of the printer is sent from the sever manager 611 .", "In this case, the procedure advances to the steps s 1503 and s 1505 from the step s 1502 for waiting for an instruction.", "Instep s 1510 , the client manager 605 decides whether or not the instruction for changing the printer is sent.", "When the instruction for changing the printer is not supplied to the client manager, the procedure returns to the step s 1502 .", "When the client manager 605 decides that the instruction for changing the printer is sent, the procedure moves to step s 1511 to notify the user of the substitute printer through the dialog box or the like on the display 207 shown in FIG. 2 .", "Then, the procedure returns to step s 1502 .", "In this case, after the printer changing process of the job is completed, only a notice of the changed result is sent or displayed.", "The server manager 611 of the print server 610 instructed to change the printer from the client manager 605 of the client 600 as described above moves to the steps S 1402 , s 1403 and s 1411 shown in FIG. 14 .", "In case of the instruction for changing the printer, the server manager 611 decides whether or not the job for which the change of the printer is instructed by the client is the job of group print on the basis of the job information.", "When the job is not the job of group print, the server manager 611 moves only the designated job in the step s 1413 .", "When the job is the job of group print, the server manager updates the GP-INFO to move to the steps 1409 and s 1410 and spool all the jobs in the group in the substitute printer.", "Further, when the printer of the grouping job is changed, the server manager 611 decides as follows.", "First, the server manager 611 decides whether the substitute printer is a face-up printer or a face-down printer.", "When the substitute printer is the face-down printer, the print job may be printed from its head, so that the print job may be controlled to be transmitted in accordance with the print order of the print order of the group designating information (GP-INFO) managed by the group job management table 616 .", "On the other hand, when the substitute printer is the face-up printer, the print job must be printed from its end.", "As for the order of pages of one print job, the print job may be spooled in the printer so that a printing operation can be performed successively from the last page thereof by using the function of the printer.", "However, in the case of the grouping job in which a plurality of print jobs are grouped to treat them as one print job, the transmission control needs to be performed from the end of the print order of the group designating information.", "Therefore, in the case where the printer is changed to the face-up printer, the spool methods are decided successively from the last print job in the print order designated by the group designating information.", "Then, when it is decided that the server spooler 612 is employed, the print job spooled in the server spooler is transmitted.", "When it is decided that the client spooler 606 is employed, a transmit permission information is sent to the client manager 605 of the client issuing the print request for the print job to be printed.", "Further, when the printer is changed from the face-up printer to the face-down printer, the server manager 611 may control the transmission of the print job by changing a print order reverse to a normal print order.", "Under this control, even when the printer is changed to a printer whose paper discharge method is different from the former printer, a printing process can be effected while the paper discharge order of the grouping job is ensured.", "The change of the printer can be designated by any client.", "However, when instructions are first outputted from other clients, only a changed result is displayed to each client like the process for automatically changing the printer of the print server.", "In accordance with the above described procedure, when a printing operation cannot be continuously performed due to the error of the printer 105 or the like before the end of all the print jobs in the group is recognized, the print server 611 can automatically change the printer to a printer designated upon default or can completely change the printer to the substitute printer in accordance with the instruction of the client manager 605 of the client 600 .", "In the above described embodiment, although the network printer is employed as the example, it should be noted that the present invention is not limited to the network printer, and any printer capable of transmitting data from the print server and obtaining the status information, such as a printer locally connected to the print server, may be utilized.", "To the case where there is provided only the spool of the job information like a virtual print server system, and, the case where a print server function is installed in the network printer, the present invention can be applied.", "According to each of the embodiments, even when a plurality of jobs are printed at arbitrary timing by a plurality of clients, the jobs can be printed together in the print order designated by the printer.", "Further, according to the embodiments of the invention, each client PC can recognize that all the jobs printed together are completely printed.", "Further, when the printing of the jobs to be printed together cannot be recognized, the printer can be changed to the substitute printer so as to print a plurality of jobs together.", "Now, the configuration of a data processing program which can be read by a print system to which the information processor of the present invention can be applied by referring to a memory map shown in FIG. 20 .", "FIG. 20 is a diagram for explaining the memory map of a memory medium for storing various types of data processing programs readable by the print system to which the present invention can be applied.", "Information for managing program groups stored in the memory medium, which is not particularly shown, for instance, version information, an implement or, etc.", "is also stored in the memory medium.", "In addition, information depending on the OS of a program read side, for instance, icons or the like for identifying and displaying the programs may be stored in the memory medium.", "Further, data dependent upon a variety of programs is managed by the above described directory.", "Still further, programs for installing these programs in a computer or a program or the like for thawing the installed program when it is compressed, etc.", "may be stored in the memory medium.", "The functions shown in FIGS. 10 to 15 in the above embodiments may be executed by the host computer on the basis of an externally installed program.", "In this case, when the information groups including programs are supplied to an output device from the external memory medium by the memory medium such as a CD-ROM, a flash memory or an FD, or through the network, the present invention may be applied.", "As mentioned above, needless to say, the memory medium on which the program code of software for achieving the functions of the above described embodiments is stored is supplied to the system or the device, and the system or the computer (or a CPU or a MPU) of the device reads and executes the program code stored in the memory medium so that the object of the present invention can be realized.", "In that case, the program code itself read from the memory medium realizes the new function of the present invention and the memory medium on which the program code is stored configures the present invention.", "As the memory medium for supplying the program code, for instance, a floppy disk, a hard disk, an optical disk, a photomagnetic disk, a CD-ROM, a CD-R, a CDRW, a DVD, a magnetic tape, a nonvolatile memory card, a ROM, an EEPROM, etc.", "may be employed.", "Further, it should be noted that the program code read by the computer is executed so that not only the functions of the embodiments can be realized, but also the OS (operating system) operating on the computer or the like performs a part or all of the actual processings by which the above described functions of the embodiments may be realized.", "Further, it should be noted that, after the program code read from the memory medium is written in a memory provided in a function expanding board inserted into the computer or a function expanding unit connected to the compute, a CPU or the like provided in the function expanding board or the function expanding unit performs a part or all of the actual processings, by which the functions of the above described embodiments may be realized.", "As many apparently widely different embodiments of the present invention can be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.", "As mentioned above, according to the present invention, since a plurality of print jobs for which the print requests are supplied from a plurality of clients are controlled and printed before all the print jobs to be grouped are prepared, even when ordinary print jobs are mixed therein and they are spooled in the print server, the printing process of the same printer can be controlled without mixing the ordinary print jobs in the group print job.", "Further, the print jobs are spooled in the client, so that the load of the network and the print server can be reduced, and the print jobs spooled in the client and the print jobs spooled in the print server can be grouped, and the print jobs can be successively transmitted and controlled according to the print order.", "Still further, even when the print information for each print job can be merely obtained from the printer, the print jobs whose print operations are finished can recognized that they are printed and discharged together and inform the client of each print job that the print jobs are printed together.", "Further, when the print jobs cannot be printed due to the error of the printer, the printer can be together changed to another designated printer.", "Further, when the printer is changed to a printer whose discharge surface is different from that of the former printer, the printer processes the print jobs in regular order by which the print jobs are received, so that a print control can be performed while a proper print order for the grouping job is maintained.", "Accordingly, even when the print jobs to be formed in an order different from the print order are successively received, they can be edited freely so as to meet the designated order, and the print jobs can be continuously printed by the same printer in an order intended by the user and can flexibly meet troubles during the printing process of the printer, the manner of the processing order of the print jobs of the printer can be expanded and the process of the printing function can be extremely improved.", "Therefore, the present invention can achieve excellent effects as mentioned above.", "Still further, the print jobs to be printed can be grouped relative to the group print jobs already managed by the management server.", "Furthermore, upon print request by the client, the user can designate a new grouping job obtained by grouping printing the print jobs from a plurality of clients.", "Additionally, when the print jobs are included in the group print job already managed by the management server, the user can easily designate the group name or the print order by employing the graphical user interface." ]
[0001] This application is a continuation-in-part application of international application no. PCT/US2005/002110, filed Jan. 24, 2005, and claims priority to U.S. provisional patent application Ser. No. 60/539,203, filed Jan. 24, 2004. BACKGROUND [0002] Radiation therapy against cancer has at least two key limitations to its effectiveness. The first is the side effects from killing non-target (i.e., non-cancerous) cells. Radiation therapy kills cancer cells by damaging key molecules in the cell, particularly DNA. Radiation can cause damage directly (e.g., by ionizing one of the atoms of the DNA molecule and this leading to strand breakage) or indirectly (e.g., by ionizing water and causing a chain of events that leads to free radical formation, where the free radicals then damage DNA or other cellular components). By either direct or indirect mechanisms, radiation is more toxic to dividing cells than non-dividing cells. Cancer is characterized by cells that divide inappropriately and in an uncontrolled manner. However, radiation kills all dividing cells, whether cancerous or not. This accounts for the side-effects of radiation, including immune suppression when bone marrow or other immune progenitor cells are irradiated, and nausea, when the gastrointestinal tract is irradiated. With a high enough dose of radiation, it is always possible to kill a tumor. The trick is to do it without killing the patient—that is, without causing an unacceptable level of damage to surrounding non-cancerous cells. Thus, the side-effects are more than just an unpleasant experience for the patient—they limit the dose and effectiveness of treatment. [0003] The second limitation of radiation's effectiveness is that non-dividing cells and cells in certain stages of the cell cycle are markedly less sensitive to radiation. Dividing cells are more sensitive to radiation at least in part because radiation is more lethal to cells in the G2 and M phases of the cell cycle, and these phases are associated with dividing cells. Cells in other phases of the cell cycle are less sensitive. Cancer cells inappropriately divide, but they are not constantly dividing. Thus, any time radiation is administered some fraction of the cancer cells will not be dividing and will be comparatively insensitive to radiation damage. [0004] Methods to enhance the effectiveness of radiation treatment for cancer are needed. Preferably the methods would decrease the side effects of treatment. Preferably the methods would enhance the lethality of radiation treatment for cancerous cells, while causing less or no increase in the lethality of the radiation to non-cancerous cells. SUMMARY [0005] In one embodiment of the invention, insulin-like growth factor-1 (IGF-1) (or an IGF-1-receptor agonist or growth hormone, which stimulates IGF-1 release) is administered to a patient before, during, or after treating the patient with radiation. Preferably, the IGF-1-receptor agonist or growth hormone is administered shortly before or immediately before treating the patient with radiation. Preferably, the radiation is externally applied, as opposed to an implanted radioisotope, so that the time span between binding IGF-1 to the cells and irradiating the cells can be controlled. [0006] Cancer cells of most or nearly all types of cancers have more IGF-1 receptors than normal cells of the same tissue type. Upon binding to IGF-1 receptors, IGF-1 stimulates cells to divide. Thus, by causing cells to divide, IGF-1 enhances the sensitivity of the cells to radiation. Since cancer cells have more IGF-1 receptors than non-cancer cells, this effect will be greater on cancer cells. Thus, administering IGF-1 increases the sensitivity of cancer cells more than non-cancer cells to radiation and increases the selectivity of radiation therapy. [0007] IGF-1 or another IGF-1-receptor agonist can be administered directly to the patient. Alternatively, growth hormone, which stimulates IGF-1 production and release in the body, can be administered. [0008] This method is effective against any type of cancer where the cancer cells have IGF-1 receptors and are responsive to IGF-1 binding. Preferably, the cancer cells have an elevated number of IGF-1 receptors (i.e., more receptors than normal cells of the same tissue type). [0009] IGF-1, another IGF-1-receptor agonist, or growth hormone can be administered systemically or locally. For instance, for local administration the agonist could be injected directly into a tumor. [0010] In addition to stimulating cancer cells to divide, IGF-1 moves a greater proportion of the cells into the G2 and M phases of the cell cycle. (Ciftci, K., 2003, J. Pharmacy Pharmacol. 55:1135.) These are the phases of the cell cycle when cells are most sensitive to radiation. (Waldow, Stephen M., Overview of Radiobiology, Chapter 9 in Introduction to Radiation Therapy. ) [0011] IGF-1, by stimulating cancers to divide, makes them more aggressive and can promote metastasis. Thus, it would be unwise to administer IGF-1 in the absence of treatment. But if IGF-1 is administered only in conjunction with radiation therapy (or chemotherapy) it will promote killing of the cancer cells by the radiation (or chemotherapy). [0012] In conjunction with administering IGF-1 at or near the time of radiation treatment, an IGF-1-receptor antagonist can be administered between treatment sessions in order to inhibit the cancer cells from dividing or metastasizing between treatment sessions. [0013] To reduce the danger of some of the cancer cells stimulated by IGF-1 surviving the radiation treatment and then becoming more aggressive, instead of administering IGF-1 (or an IGF-1-receptor agonist or growth hormone) to the patient, an IGF-1-chemotherapeutic agent conjugate (e.g., IGF-1-methotrexate) can be administered to the patient in conjunction with radiation treatment. See U.S. provisional patent application 60/513,048, filed Oct. 21, 2003, and U.S. utility patent application Ser. No. 11/407,590, filed Apr. 20, 2006, for a description of the conjugates. If a conjugate is administered instead of IGF-1, any cells stimulated by the IGF-1 portion of the conjugate will take up the chemotherapeutic agent along with IGF-1. Thus, they are less likely to survive the treatment. (The conjugate could also be a conjugate of another IGF-1-receptor agonist, instead of IGF-1 itself, to a chemotherapeutic agent.) Insulin has properties similar to IGF-1. For one thing, insulin and IGF-1 are homologous (evolutionarily related) proteins. They cross-react to each other's receptors. Insulin has been shown to enhance the killing of breast cancer cells in tissue culture by up to 10,000 fold. This does not appear to be because insulin enhances uptake of methotrexate. Another study found it only enhanced uptake of methotrexate by a factor of 2. Thus, the more likely hypothesis is that insulin enhances methotrexate killing by stimulating the cancer cells to divide, and thus making them more sensitive. Insulin is also known to stimulate cells bearing insulin receptors to divide. In part, insulin's effect of stimulating cells to divide may be because insulin binds to IGF-1 receptors (although at a lower affinity than IGF-1 does). Cancer cell of most or nearly all types of cancer have more insulin receptors, as well as IGF-1 receptors, than normal cells of the same tissue type. [0014] Thus, the invention also provides for administering insulin or another insulin-receptor agonist to a patient immediately before, or shortly before, radiation treatment, instead of or together with administering IGF-1. In addition, just as IGF-1 release could be stimulated by administering growth hormone, insulin release could be stimulated by administering sugar, either orally or intravenously, to the patient. Thus, the invention provides for administering sugar to a patient immediately before or shortly before radiation treatment. The combination of insulin and sugar can also be more effective than either alone in stimulating activity of cancer cells and sensitizing the cancer cells to radiation therapy. [0015] Using insulin to enhance radiation effectiveness is effective against any type of cancer where the cancer cells have insulin receptors and are responsive to insulin. Preferably the cancer cells have an elevated number of insulin receptors (i.e., more receptors than normal cells of the same tissue type). [0016] Insulin or an insulin-receptor agonist can be administered systemically or locally. For instance, for local administration insulin or the agonist could be injected directly into a tumor. [0017] Insulin, by stimulating cancer cells to divide, can make them more aggressive and can promote metastasis. Thus, it would be unwise to administer insulin in the absence of radiation treatment or chemotherapy. Between treatments, in order to prevent stimulating the cancer cells to divide and be active, the patient should be advised to minimize sugar consumption (and thus insulin production). Also, an insulin-receptor antagonist could be administered. [0018] To reduce the danger of some of the cancer cells stimulated by insulin surviving the radiation treatment and then becoming more aggressive, instead of administering insulin (or an insulin-receptor agonist or sugar) to the patient, an insulin-chemotherapeutic agent conjugate (e.g., insulin-methotrexate) can be administered to the patient in conjunction with radiation treatment. See U.S. provisional patent application 60/513,048, filed Oct. 21, 2003, for a description of the conjugates. If a conjugate is administered instead of insulin, any cells stimulated by the insulin portion of the conjugate will take up the chemotherapeutic agent along with insulin. Thus, they are less likely to survive the treatment. (The conjugate could also be a conjugate of an insulin-receptor agonist, instead of insulin itself, to a chemotherapeutic agent.) One aspect of the invention is enhancing the effectiveness of radiation therapy by coadministering both (1) IGF-1, another IGF-1-receptor agonist, or growth hormone; and (2) insulin, another insulin-receptor agonist, or sugar, before during or after administering radiation to a mammal afflicted with cancer. While most cancer cells have an elevated number of IGF-1 receptors and most have an elevated number of insulin receptors, some may be more elevated in one than the other, and some may be more responsive to one than the other. Thus, it can be advantageous to administer both an insulin-receptor agonist and an IGF-1-receptor agonist. Administering both is insurance against the cancer cells being more responsive to one than the other. Furthermore, the effects of an insulin-receptor agonist and an IGF-1-receptor agonist in enhancing the effectiveness of radiation are expected to be additive. [0019] Thus, the invention provides a method of treating cancer in a mammal involving: administering an agent containing an IGF-1-receptor agonist to the mammal and administering radiation to the mammal. [0020] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal involving: administering an agent containing an IGF-1-receptor agonist to the mammal before, during, or after administering radiation to the mammal. [0021] Another embodiment of the invention provides a method of screening for agents that enhance the effectiveness of radiation therapy, the method involving: (a) contacting cancer cells with an IGF-1-receptor agonist-chemotherapeutic agent conjugate and irradiating the cancer cells, and measuring the survival of the cancer cells; (b) irradiating the cancer cells wherein the cancer cells are not contacted with the conjugate, and measuring the survival of the cancer cells; and (c) comparing the survival of the cancer cells in (a) and (b). [0022] Another embodiment of the invention provides a method of screening for agents that enhance the effectiveness of radiation therapy, the method involving: (a) contacting cancer cells with an insulin-receptor agonist-chemotherapeutic agent conjugate and irradiating the cancer cells, and measuring the survival of the cancer cells; (b) irradiating the cancer cells wherein the cancer cells are not contacted with the conjugate, and measuring the survival of the cancer cells; and (c) comparing the survival of the cancer cells in (a) and (b). [0023] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering a growth hormone-receptor agonist to the mammal and administering radiation to the mammal. [0024] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal comprising: administering a growth hormone-receptor agonist to the mammal before, during, or after administering radiation to the mammal. [0025] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering an insulin-receptor agonist-chemotherapeutic agent conjugate to the mammal before, during, or after administering radiation to the mammal. [0026] Another embodiment of the invention provides a method of enhancing the effectiveness of radiation therapy in a mammal involving: administering an insulin-receptor agonist-chemotherapeutic agent conjugate to the mammal before, during, or after administering radiation to the mammal. [0027] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering an agent containing an IGF-1-receptor agonist or administering growth hormone to the mammal; administering an agent containing an insulin-receptor agonist or administering sugar to the mammal; and administering radiation to the mammal. [0028] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal involving: administering an agent comprising an IGF-1-receptor agonist or growth hormone to the mammal before, during, or after administering radiation to the mammal; and administering an agent comprising an insulin-receptor agonist or sugar to the mammal before, during, or after administering radiation to the mammal. DETAILED DESCRIPTION Definitions [0029] The terms “chemotherapeutic agent” or “anti-cancer chemotherapeutic agent” are used interchangeably herein. The terms refer to a synthetic, biological, or semi-synthetic compound that kills cancer cells or inhibits the growth of cancer cells while having less effect on non-cancerous cells. The terms include enzymes that have anti-cancer properties, e.g., asparaginase, and photoactivatable anti-cancer agents, e.g., chlorin e-6. [0030] The term “treating cancer” includes, e.g., preventing metastasis, inhibiting growth of a cancer, or stopping the growth of cancer, as well as killing a tumor. [0031] The term “binding affinity” of a ligand for a particular receptor refers to the association constant K A (the inverse of the dissociation constant K D ) or to experimentally determined approximations thereof. [0032] The term “agonist” refers to a ligand to the insulin receptor or IGF-1 receptor that, when it binds to the receptor, activates the normal biochemical and physiological events triggered by binding of the natural ligand for the receptor (i.e, insulin for the insulin receptor or IGF-1 for the IGF-1 receptor). In particular embodiments, an agonist has at least 20%, at least 30%, or at least 50% of the biological activity of the natural ligand. The activity of an insulin receptor ligand can be measured, for instance, by measuring the hypoglycemic effect (Poznansky, M. J., et al., 1984, Science 223:1304). The activity of an insulin-receptor ligand or IGF-1-receptor ligand can be measured in vitro by the measuring the extent of autophosphorylation of the receptor in response to ligand binding, as described in Satyamarthy, K., et al., 2001, Cancer Res. 61:7318. MAP kinase phosphorylation can also be measured for the IGF-1 receptor (Satyamarthy, K., et al., 2001, Cancer Res. 61:7318). [0033] The term “antagonist” refers to a ligand that has little or no stimulating activity when it binds to the receptor and that inhibits or prevents binding of the natural ligand to the receptor. In particular embodiments, an antagonist has less than 20%, less than 10%, or less than 5% of the activity of the natural ligand (insulin for the insulin receptor or IGF-1 for the IGF-1 receptor). [0034] “Containing” as used herein is open-ended; i.e., it allows the inclusion of other unnamed elements and has the same meaning as “comprising.” Description [0035] The invention involves administering to a mammal afflicted with cancer radiation and one or more agents that sensitize cancer cells in the mammal to killing by the radiation. The sensitizing agents can be an IGF-1-receptor agonist, an insulin-receptor agonist, growth hormone (which causes the release of IGF-1 in the mammal), and/or a sugar (which causes the release of insulin in the mammal). [0036] The agents can be administered before, during, or after administration of the radiation. The agents are administered close enough in time to the radiation to enhance the effectiveness of the radiation in killing cancer cells. This is typically at least within 12 hours before or after administration of the radiation. Preferably, the agents are administered 0 to 6 hours before the radiation is administered. More preferably, the agents are administered 0 to 3 hours or 15 minutes to 3 hours before the radiation is administered. In particular embodiments, the agents are administered between 6 hours before and 6 hours after the radiation is administered. In another particular embodiment, the agents are administered between 3 hours before and 3 hours after the radiation is administered. [0037] One embodiment of the invention provides a method of treating cancer in a mammal comprising: administering an agent comprising an IGF-1-receptor agonist to the mammal and administering radiation to the mammal. [0038] In particular embodiments, the IGF-1-receptor agonist is IGF-1. In another particular embodiment, the agent consists of IGF-1. [0039] In particular embodiments, the IGF-1-receptor agonist is not an insulin-receptor agonist. [0040] In specific embodiments, the IGF-1-receptor agonist has a K D for the insulin receptor of greater than 0.5 nM, greater than 1 nM, or greater than 2 nM. [0041] In specific embodiments, the IGF-1-receptor agonist has a binding affinity for the IGF-1 receptor greater than insulin. In specific embodiments, the IGF-1-receptor agonist has a binding affinity for the IGF-1 receptor greater than for the insulin receptor. [0042] In particular embodiments of the invention, the IGF-1-receptor agonist or antagonist has a K D for the IGF-1 receptor of less than 1 mM, less than 100 μM, less than 10 μM, less than 1 μM, less than 100 nM, less than 50 nM, less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM. [0043] In particular embodiments, the IGF-1-receptor agonist is not IGF-1. [0044] The IGF-1-receptor agonist can be a peptide in some embodiments. For instance, it can be a peptide of 2-60 amino acid residues, of 2-40 amino acid residues, of 2-20 amino acid residues, of 5-60 amino acid residues, of 5-40 amino acid residues, or of 5-20 amino acid residues. [0045] In particular embodiments of the methods using an agent that comprises an IGF-1-receptor agonist or an insulin-receptor agonist, the agent is, or comprises, an IGF-1-receptor agonist-chemotherapeutic agent conjugate or an insulin-receptor agonist-chemotherapeutic agent conjugate. [0046] The chemotherapeutic agent portion of the conjugates in particular embodiments is amsacrine, azacytidine, bleomycin, busulfan, capecitabine, carboplatin, carmustine, chlorambucil, cisplatin, cladribine, cyclophosphamide, cytarabine, dactinomycin, daunorubicin, decarbazine, docetaxel, doxorubicin, epirubicin, estramustine, etoposide, floxuridine, fludarabine, fluorouracil, gemcitabine, hexamethylmelamine, idarubicin, ifosfamide, irinotecan, lomustine, mechlorethamine, melphalan, mercaptopurine, mitomycin C, mitotane, mitoxantrone, oxaliplatin, paclitaxel, pemetrexed, pentostatin, plicamycin, procarbazine, ralitrexed, semustine, streptozocin, temozolamide, teniposide, thioguanine, thiotepa, topotecan, trimitrexate, valrubicin, vincristine, vinblastine, vindestine, or vinorelbine. [0047] Other examples of IGF-1-receptor agonists include variants of IGF-1 that activate the receptor but have reduced affinity for the soluble IGF-1 binding proteins, such as those disclosed in U.S. Pat. No. 4,876,242. IGF binding proteins are natural serum proteins that bind to IGF-1, holding it in circulation and extending its biological half-life. It may be advantageous for the IGF-1 receptor ligands of this invention to have reduced binding to the IGF-1 binding proteins, because that reduced binding would accelerate the release of the agent to bind to the IGF-1 receptors. Thus, in some embodiments, the IGF-1 receptor ligand or agonist has reduced affinity for soluble IGF-1 binding proteins, as compared to native IGF-1. [0048] One preferred variant IGF-1 for use in the methods and conjugates of the invention that has reduced binding affinity for the soluble IGF-1 binding proteins is LONG-R3-IGF-1 (Francis, G. L., et al.1992, J Mol. Endocrinol. 8:213-223; Tomas, F. M. et al., 1993, . J. Endocrinol. 137:413-421) (SEQ ID NO:1). SEQ ID NO:1 has the sequence MFPAMPLSSL FVNGPRTLCG AELVDALQFV CGDRGFYFNK PTGYSSSRRA PQTGIVDECC FRSCDLRRLE MYCAPLKPAK SA. [0049] Preferably, the IGF-1 receptor ligand with reduced affinity for soluble IGF-1 binding proteins has at least 5-fold, more preferably at least 10-fold, more preferably still at least 100-fold lower binding affinity for soluble IGF-1 binding proteins than wild-type IGF-1. Binding affinity for the soluble IGF-1 binding proteins can be measured by a competition binding assay against labeled IGF-1 (e.g., I-125-IGF-1), using a mixture of purified IGF-1 binding proteins or rat L6 myoblast-conditioned medium (a naturally produced mixture of IGF-1 binding proteins), as described in Francis, G. L., et al. (1992, J Mol. Endocrinol. 8:213-223); Szabo, L. et al. (1988, Biochem. Biophys. Res. Commun. 151:207-214); and Martin, J. L. et al. (1986, J Biol. Chem. 261:8754-8760). Preferably, the variant IGF-1 has an IC 50 in a competition binding assay against labeled wild-type IGF-1 for binding to soluble IGF-1 binding proteins in L6 myoblast-conditioned medium of greater than 10 nM, more preferably greater than 100 nM. [0050] Preferably, the variant IGF-1 with reduced affinity for soluble IGF-1 binding proteins has affinity for the IGF-1 receptor that is close to wild-type IGF-1 (e.g., less than 30-fold greater than wild-type IGF-1, more preferably less than 10-fold greater than wild-type IGF-1). In specific embodiments, the variant IGF-1 has an IC 50 in a competition binding assay against labeled wild-type IGF-1 for binding to IGF-1 receptors (e.g., on MCF-7 cells) of less than 50 nM, more preferably less than 10 nM, more preferably still less than 5 nM, more preferably still less than 3 nM). This assay is described in Ross, M. et al. (1989, Biochem. J. 258:267-272) and Francis, G. L., et al. (1992, J. Mol. Endocrinol. 8:213-223). [0051] In embodiments of the invention involving use of an agent comprising an insulin-receptor agonist, the insulin-receptor agonist may be insulin. [0052] In particular embodiments, the insulin-receptor agonist is glycyl-L-histidyl-L-lysine-acetate (Biaglow, J. E., et al., 1979, Int. J. Radiat. Oncol. Biol. Phys. 5:1669). [0053] In particular embodiments of the invention, the insulin-receptor agonist is not an IGF-1-receptor agonist. [0054] In specific embodiments, the insulin-receptor agonist has a K D for the IGF-1 receptor of greater than 0.5 nM, greater than 1 nM, or greater than 2 nM. [0055] In specific embodiments, the insulin-receptor agonist has a binding affinity for the insulin receptor greater than IGF-1. [0056] In particular embodiments of the invention, the insulin-receptor agonist or antagonist has a K D for the insulin receptor of less than 1 mM, less than 100 μM, less than 10 μM, less than 1 μM, less than 100 nM, less than 50 nM, less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM. [0057] The insulin-receptor agonist can be a peptide in some embodiments. For instance, it can be a peptide of 2-60 amino acid residues, of 2-40 amino acid residues, of 2-20 amino acid residues, of 5-60 amino acid residues, of 5-40 amino acid residues, or of 5-20 amino acid residues. [0058] In particular embodiments of the invention, the methods are used to treat lung cancer (small cell or non-small cell), prostate cancer, colorectal cancer, breast cancer, pancreatic cancer, leukemia, liver cancer, stomach cancer, ovarian cancer, uterine cancer, testicular cancer, brain cancer, non-Hodgkin's lymphoma, Hodgkin's lymphoma, Ewing's sarcoma, osteosarcoma, neuroblastoma, rhabdomyosarcoma, melanoma, head or neck cancer, or brain cancer. [0059] The methods of the invention may be particularly suited for treatment of low-grade non-Hodgkin's lymphoma. Low-grade non-Hodgkin's lymphoma is less curable than intermediate-grade or aggressive-grade non-Hodgkin's lymphoma because the cancer cells in low-grade non-Hodgkin's lymphoma divide less frequently and are thus less susceptible to radiation therapy than intermediate and aggressive-grade lymphomas. The agents described herein will cause the tumor cells to divide more frequently and thus be more sensitive to radiation killing. [0060] In particular embodiments of the methods described herein, the mammal treated by the methods is a human. In other embodiments, the mammal is an experimental mammal, e.g., a mouse. In particular embodiments, the mammal is a dog, cat, rabbit, guinea pig, or pig. [0061] The invention involves inducing cancer cell division by administering to a mammal afflicted with cancer an IGF-1-receptor agonist, an insulin-receptor agonist, a growth hormone receptor agonist, and/or a sugar, at approximately the time radiation administered to enhance the effectiveness of anti-cancer radiation therapy. In the periods between radiation therapy, it is advisable to try to prevent cancer cell division. Thus, the invention can involve administering in the periods between radiation therapy an IGF-1 receptor antagonist (e.g., a monoclonal antibody against the IGF-1 receptor) or an insulin-receptor antagonist (e.g., a monoclonal antibody against the insulin receptor) to the mammal. [0062] One embodiment involves administering a radiation-sensitizing agent described herein 0 to 12 hours before administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 0 to 12 hours before administration of radiation to the mammal. [0063] One embodiment involves administering a radiation-sensitizing agent described herein between 6 hours before and 6 hours after administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 6 hours before to 6 hours after administration of radiation to the mammal. [0064] One embodiment involves administering a radiation-sensitizing agent described herein between 3 hours before and 3 hours after administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 3 hours before to 3 hours after administration of radiation to the mammal. [0065] The invention will now be illustrated by the following non-limiting examples. EXAMPLES Example 1 In vitro Assays [0066] MiaPaCa (a human pancreatic cancer cell line), LnCap (a human prostate cancer cell line), H226 and A549 (two human lung cancer cell lines) are grown in monolayer cultures in McCoy's 5A medium containing 10% fetal bovine serum and buffered with 2.0 g/L sodium bicarbonate and 0.02 M Hepes, pH 7.4. The cells are at seeded at 6×10 4 cells per T30 flask. On day 3 the medium is changed. The cells are irradiated at either 4 days (exponential cells) or 7 days (plateau-phase cells). Twenty minutes before, 2 hours before, or immediately before irradiation, insulin (0.01, 0.1, or 1 μg/ml) or IGF-1 (3, 20, or 150 ng/ml) is added to the medium. Control cells have no added hormone. The cells are then irradiated with 200 rads X-rays. After irradiation, the cells are allowed to recover in the used medium for 60 minutes. [0067] The cells are then typsinized and plated in fresh medium. The surviving fraction of a specific number of plated cells is determined by staining colonies with methylene blue after 7-10 days of growth. [0068] These experiments show that at at least some concentrations and times before irradiation, both insulin and IGF increase cell killing by radiation in plateau-phase cells. [0069] Exponential phase cells are also sensitized to radiation by both insulin and IGF-1. [0070] Exponential-phase and plateau-phase cells are then treated with insulin and IGF-1 separately and together at their experimentally determined optimal concentrations immediately before, 15 minutes before, and 2 hours before irradiation with a range of radiation doses. Again, the cells are trypsinized and plated, and the percent surviving is determined. It is found that the effect of both hormones together is greater than either alone in enhancing killing. [0071] Exponential- and plateau-phase cells are then treated with insulin at the optimal concentration in combination with 30 mM glucose. It is found that the addition of glucose enhances radiation killing above that observed with insulin alone. Example 2 In vivo Assays [0072] LnCap, MiaPaCa, H226, and A549 cells are grown in culture. Cells are harvested using 0.25% trypsin, washed, suspended in Dulbecco's PBS, and counted. 1×10 6 cells are injected subcutaneously into the hind thigh of male nude mice. Tumors are grown to 250 mm 3 in ˜21 days. Tumors are measured with a caliper, and the tumor size is calculated by the formula a 2 b/2, where a and b are the shorter and longer diameters of the tumor, respectively. [0073] When the tumors reach 250 mm 3 , the mice are treated with insulin (5 or 40 μg/kg), IGF-1 (5 or 100 μg/kg) or insulin+glucose (5 g glucose/kg), or growth hormone (50 or 500 μg/kg), or saline control 30 minutes before radiation treatment. [0074] The mice are anesthetized immediately before radiation treatment, and then the tumor-bearing leg is irradiated with X-rays at 1.4 Gy/minute, receiving a dose of 15 Gy. [0075] The growth of tumor volume in the mice after irradiation is followed for 3 weeks. [0076] These experiments will show insulin, insulin+glucose, IGF-1, and growth hormone all enhance the effectiveness of radiation therapy. [0077] All patents, patent documents, and other references cited herein are incorporated by reference.
Methods of treating cancer are provided. The methods are improved methods of radiation therapy involving administering an IGF-1-receptor agonist along with therapeutic radiation to a mammal afflicted with cancer. The IGF-1-receptor agonist causes the cancer cells to divide and move into more sensitive stages of the cell cycle, sensitizing the cancer cells to be killed more efficiently by radiation. Also provided are methods of treating cancer involving administering radiation to a mammal together with administering a growth-hormone agonist, an insulin-receptor agonist, or sugar.
Provide a concise summary of the essential information conveyed in the context.
[ "[0001] This application is a continuation-in-part application of international application no. PCT/US2005/002110, filed Jan. 24, 2005, and claims priority to U.S. provisional patent application Ser.", "No. 60/539,203, filed Jan. 24, 2004.", "BACKGROUND [0002] Radiation therapy against cancer has at least two key limitations to its effectiveness.", "The first is the side effects from killing non-target (i.e., non-cancerous) cells.", "Radiation therapy kills cancer cells by damaging key molecules in the cell, particularly DNA.", "Radiation can cause damage directly (e.g., by ionizing one of the atoms of the DNA molecule and this leading to strand breakage) or indirectly (e.g., by ionizing water and causing a chain of events that leads to free radical formation, where the free radicals then damage DNA or other cellular components).", "By either direct or indirect mechanisms, radiation is more toxic to dividing cells than non-dividing cells.", "Cancer is characterized by cells that divide inappropriately and in an uncontrolled manner.", "However, radiation kills all dividing cells, whether cancerous or not.", "This accounts for the side-effects of radiation, including immune suppression when bone marrow or other immune progenitor cells are irradiated, and nausea, when the gastrointestinal tract is irradiated.", "With a high enough dose of radiation, it is always possible to kill a tumor.", "The trick is to do it without killing the patient—that is, without causing an unacceptable level of damage to surrounding non-cancerous cells.", "Thus, the side-effects are more than just an unpleasant experience for the patient—they limit the dose and effectiveness of treatment.", "[0003] The second limitation of radiation's effectiveness is that non-dividing cells and cells in certain stages of the cell cycle are markedly less sensitive to radiation.", "Dividing cells are more sensitive to radiation at least in part because radiation is more lethal to cells in the G2 and M phases of the cell cycle, and these phases are associated with dividing cells.", "Cells in other phases of the cell cycle are less sensitive.", "Cancer cells inappropriately divide, but they are not constantly dividing.", "Thus, any time radiation is administered some fraction of the cancer cells will not be dividing and will be comparatively insensitive to radiation damage.", "[0004] Methods to enhance the effectiveness of radiation treatment for cancer are needed.", "Preferably the methods would decrease the side effects of treatment.", "Preferably the methods would enhance the lethality of radiation treatment for cancerous cells, while causing less or no increase in the lethality of the radiation to non-cancerous cells.", "SUMMARY [0005] In one embodiment of the invention, insulin-like growth factor-1 (IGF-1) (or an IGF-1-receptor agonist or growth hormone, which stimulates IGF-1 release) is administered to a patient before, during, or after treating the patient with radiation.", "Preferably, the IGF-1-receptor agonist or growth hormone is administered shortly before or immediately before treating the patient with radiation.", "Preferably, the radiation is externally applied, as opposed to an implanted radioisotope, so that the time span between binding IGF-1 to the cells and irradiating the cells can be controlled.", "[0006] Cancer cells of most or nearly all types of cancers have more IGF-1 receptors than normal cells of the same tissue type.", "Upon binding to IGF-1 receptors, IGF-1 stimulates cells to divide.", "Thus, by causing cells to divide, IGF-1 enhances the sensitivity of the cells to radiation.", "Since cancer cells have more IGF-1 receptors than non-cancer cells, this effect will be greater on cancer cells.", "Thus, administering IGF-1 increases the sensitivity of cancer cells more than non-cancer cells to radiation and increases the selectivity of radiation therapy.", "[0007] IGF-1 or another IGF-1-receptor agonist can be administered directly to the patient.", "Alternatively, growth hormone, which stimulates IGF-1 production and release in the body, can be administered.", "[0008] This method is effective against any type of cancer where the cancer cells have IGF-1 receptors and are responsive to IGF-1 binding.", "Preferably, the cancer cells have an elevated number of IGF-1 receptors (i.e., more receptors than normal cells of the same tissue type).", "[0009] IGF-1, another IGF-1-receptor agonist, or growth hormone can be administered systemically or locally.", "For instance, for local administration the agonist could be injected directly into a tumor.", "[0010] In addition to stimulating cancer cells to divide, IGF-1 moves a greater proportion of the cells into the G2 and M phases of the cell cycle.", "(Ciftci, K., 2003, J. Pharmacy Pharmacol.", "55:1135.) These are the phases of the cell cycle when cells are most sensitive to radiation.", "(Waldow, Stephen M., Overview of Radiobiology, Chapter 9 in Introduction to Radiation Therapy.", ") [0011] IGF-1, by stimulating cancers to divide, makes them more aggressive and can promote metastasis.", "Thus, it would be unwise to administer IGF-1 in the absence of treatment.", "But if IGF-1 is administered only in conjunction with radiation therapy (or chemotherapy) it will promote killing of the cancer cells by the radiation (or chemotherapy).", "[0012] In conjunction with administering IGF-1 at or near the time of radiation treatment, an IGF-1-receptor antagonist can be administered between treatment sessions in order to inhibit the cancer cells from dividing or metastasizing between treatment sessions.", "[0013] To reduce the danger of some of the cancer cells stimulated by IGF-1 surviving the radiation treatment and then becoming more aggressive, instead of administering IGF-1 (or an IGF-1-receptor agonist or growth hormone) to the patient, an IGF-1-chemotherapeutic agent conjugate (e.g., IGF-1-methotrexate) can be administered to the patient in conjunction with radiation treatment.", "See U.S. provisional patent application 60/513,048, filed Oct. 21, 2003, and U.S. utility patent application Ser.", "No. 11/407,590, filed Apr. 20, 2006, for a description of the conjugates.", "If a conjugate is administered instead of IGF-1, any cells stimulated by the IGF-1 portion of the conjugate will take up the chemotherapeutic agent along with IGF-1.", "Thus, they are less likely to survive the treatment.", "(The conjugate could also be a conjugate of another IGF-1-receptor agonist, instead of IGF-1 itself, to a chemotherapeutic agent.) Insulin has properties similar to IGF-1.", "For one thing, insulin and IGF-1 are homologous (evolutionarily related) proteins.", "They cross-react to each other's receptors.", "Insulin has been shown to enhance the killing of breast cancer cells in tissue culture by up to 10,000 fold.", "This does not appear to be because insulin enhances uptake of methotrexate.", "Another study found it only enhanced uptake of methotrexate by a factor of 2.", "Thus, the more likely hypothesis is that insulin enhances methotrexate killing by stimulating the cancer cells to divide, and thus making them more sensitive.", "Insulin is also known to stimulate cells bearing insulin receptors to divide.", "In part, insulin's effect of stimulating cells to divide may be because insulin binds to IGF-1 receptors (although at a lower affinity than IGF-1 does).", "Cancer cell of most or nearly all types of cancer have more insulin receptors, as well as IGF-1 receptors, than normal cells of the same tissue type.", "[0014] Thus, the invention also provides for administering insulin or another insulin-receptor agonist to a patient immediately before, or shortly before, radiation treatment, instead of or together with administering IGF-1.", "In addition, just as IGF-1 release could be stimulated by administering growth hormone, insulin release could be stimulated by administering sugar, either orally or intravenously, to the patient.", "Thus, the invention provides for administering sugar to a patient immediately before or shortly before radiation treatment.", "The combination of insulin and sugar can also be more effective than either alone in stimulating activity of cancer cells and sensitizing the cancer cells to radiation therapy.", "[0015] Using insulin to enhance radiation effectiveness is effective against any type of cancer where the cancer cells have insulin receptors and are responsive to insulin.", "Preferably the cancer cells have an elevated number of insulin receptors (i.e., more receptors than normal cells of the same tissue type).", "[0016] Insulin or an insulin-receptor agonist can be administered systemically or locally.", "For instance, for local administration insulin or the agonist could be injected directly into a tumor.", "[0017] Insulin, by stimulating cancer cells to divide, can make them more aggressive and can promote metastasis.", "Thus, it would be unwise to administer insulin in the absence of radiation treatment or chemotherapy.", "Between treatments, in order to prevent stimulating the cancer cells to divide and be active, the patient should be advised to minimize sugar consumption (and thus insulin production).", "Also, an insulin-receptor antagonist could be administered.", "[0018] To reduce the danger of some of the cancer cells stimulated by insulin surviving the radiation treatment and then becoming more aggressive, instead of administering insulin (or an insulin-receptor agonist or sugar) to the patient, an insulin-chemotherapeutic agent conjugate (e.g., insulin-methotrexate) can be administered to the patient in conjunction with radiation treatment.", "See U.S. provisional patent application 60/513,048, filed Oct. 21, 2003, for a description of the conjugates.", "If a conjugate is administered instead of insulin, any cells stimulated by the insulin portion of the conjugate will take up the chemotherapeutic agent along with insulin.", "Thus, they are less likely to survive the treatment.", "(The conjugate could also be a conjugate of an insulin-receptor agonist, instead of insulin itself, to a chemotherapeutic agent.) One aspect of the invention is enhancing the effectiveness of radiation therapy by coadministering both (1) IGF-1, another IGF-1-receptor agonist, or growth hormone;", "and (2) insulin, another insulin-receptor agonist, or sugar, before during or after administering radiation to a mammal afflicted with cancer.", "While most cancer cells have an elevated number of IGF-1 receptors and most have an elevated number of insulin receptors, some may be more elevated in one than the other, and some may be more responsive to one than the other.", "Thus, it can be advantageous to administer both an insulin-receptor agonist and an IGF-1-receptor agonist.", "Administering both is insurance against the cancer cells being more responsive to one than the other.", "Furthermore, the effects of an insulin-receptor agonist and an IGF-1-receptor agonist in enhancing the effectiveness of radiation are expected to be additive.", "[0019] Thus, the invention provides a method of treating cancer in a mammal involving: administering an agent containing an IGF-1-receptor agonist to the mammal and administering radiation to the mammal.", "[0020] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal involving: administering an agent containing an IGF-1-receptor agonist to the mammal before, during, or after administering radiation to the mammal.", "[0021] Another embodiment of the invention provides a method of screening for agents that enhance the effectiveness of radiation therapy, the method involving: (a) contacting cancer cells with an IGF-1-receptor agonist-chemotherapeutic agent conjugate and irradiating the cancer cells, and measuring the survival of the cancer cells;", "(b) irradiating the cancer cells wherein the cancer cells are not contacted with the conjugate, and measuring the survival of the cancer cells;", "and (c) comparing the survival of the cancer cells in (a) and (b).", "[0022] Another embodiment of the invention provides a method of screening for agents that enhance the effectiveness of radiation therapy, the method involving: (a) contacting cancer cells with an insulin-receptor agonist-chemotherapeutic agent conjugate and irradiating the cancer cells, and measuring the survival of the cancer cells;", "(b) irradiating the cancer cells wherein the cancer cells are not contacted with the conjugate, and measuring the survival of the cancer cells;", "and (c) comparing the survival of the cancer cells in (a) and (b).", "[0023] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering a growth hormone-receptor agonist to the mammal and administering radiation to the mammal.", "[0024] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal comprising: administering a growth hormone-receptor agonist to the mammal before, during, or after administering radiation to the mammal.", "[0025] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering an insulin-receptor agonist-chemotherapeutic agent conjugate to the mammal before, during, or after administering radiation to the mammal.", "[0026] Another embodiment of the invention provides a method of enhancing the effectiveness of radiation therapy in a mammal involving: administering an insulin-receptor agonist-chemotherapeutic agent conjugate to the mammal before, during, or after administering radiation to the mammal.", "[0027] Another embodiment of the invention provides a method of treating cancer in a mammal involving: administering an agent containing an IGF-1-receptor agonist or administering growth hormone to the mammal;", "administering an agent containing an insulin-receptor agonist or administering sugar to the mammal;", "and administering radiation to the mammal.", "[0028] Another embodiment of the invention provides a method of enhancing the effectiveness of anti-cancer radiation therapy in a mammal involving: administering an agent comprising an IGF-1-receptor agonist or growth hormone to the mammal before, during, or after administering radiation to the mammal;", "and administering an agent comprising an insulin-receptor agonist or sugar to the mammal before, during, or after administering radiation to the mammal.", "DETAILED DESCRIPTION Definitions [0029] The terms “chemotherapeutic agent”", "or “anti-cancer chemotherapeutic agent”", "are used interchangeably herein.", "The terms refer to a synthetic, biological, or semi-synthetic compound that kills cancer cells or inhibits the growth of cancer cells while having less effect on non-cancerous cells.", "The terms include enzymes that have anti-cancer properties, e.g., asparaginase, and photoactivatable anti-cancer agents, e.g., chlorin e-6.", "[0030] The term “treating cancer”", "includes, e.g., preventing metastasis, inhibiting growth of a cancer, or stopping the growth of cancer, as well as killing a tumor.", "[0031] The term “binding affinity”", "of a ligand for a particular receptor refers to the association constant K A (the inverse of the dissociation constant K D ) or to experimentally determined approximations thereof.", "[0032] The term “agonist”", "refers to a ligand to the insulin receptor or IGF-1 receptor that, when it binds to the receptor, activates the normal biochemical and physiological events triggered by binding of the natural ligand for the receptor (i.", "e, insulin for the insulin receptor or IGF-1 for the IGF-1 receptor).", "In particular embodiments, an agonist has at least 20%, at least 30%, or at least 50% of the biological activity of the natural ligand.", "The activity of an insulin receptor ligand can be measured, for instance, by measuring the hypoglycemic effect (Poznansky, M. J., et al.", ", 1984, Science 223:1304).", "The activity of an insulin-receptor ligand or IGF-1-receptor ligand can be measured in vitro by the measuring the extent of autophosphorylation of the receptor in response to ligand binding, as described in Satyamarthy, K., et al.", ", 2001, Cancer Res.", "61:7318.", "MAP kinase phosphorylation can also be measured for the IGF-1 receptor (Satyamarthy, K., et al.", ", 2001, Cancer Res.", "61:7318).", "[0033] The term “antagonist”", "refers to a ligand that has little or no stimulating activity when it binds to the receptor and that inhibits or prevents binding of the natural ligand to the receptor.", "In particular embodiments, an antagonist has less than 20%, less than 10%, or less than 5% of the activity of the natural ligand (insulin for the insulin receptor or IGF-1 for the IGF-1 receptor).", "[0034] “Containing”", "as used herein is open-ended;", "i.e., it allows the inclusion of other unnamed elements and has the same meaning as “comprising.”", "Description [0035] The invention involves administering to a mammal afflicted with cancer radiation and one or more agents that sensitize cancer cells in the mammal to killing by the radiation.", "The sensitizing agents can be an IGF-1-receptor agonist, an insulin-receptor agonist, growth hormone (which causes the release of IGF-1 in the mammal), and/or a sugar (which causes the release of insulin in the mammal).", "[0036] The agents can be administered before, during, or after administration of the radiation.", "The agents are administered close enough in time to the radiation to enhance the effectiveness of the radiation in killing cancer cells.", "This is typically at least within 12 hours before or after administration of the radiation.", "Preferably, the agents are administered 0 to 6 hours before the radiation is administered.", "More preferably, the agents are administered 0 to 3 hours or 15 minutes to 3 hours before the radiation is administered.", "In particular embodiments, the agents are administered between 6 hours before and 6 hours after the radiation is administered.", "In another particular embodiment, the agents are administered between 3 hours before and 3 hours after the radiation is administered.", "[0037] One embodiment of the invention provides a method of treating cancer in a mammal comprising: administering an agent comprising an IGF-1-receptor agonist to the mammal and administering radiation to the mammal.", "[0038] In particular embodiments, the IGF-1-receptor agonist is IGF-1.", "In another particular embodiment, the agent consists of IGF-1.", "[0039] In particular embodiments, the IGF-1-receptor agonist is not an insulin-receptor agonist.", "[0040] In specific embodiments, the IGF-1-receptor agonist has a K D for the insulin receptor of greater than 0.5 nM, greater than 1 nM, or greater than 2 nM.", "[0041] In specific embodiments, the IGF-1-receptor agonist has a binding affinity for the IGF-1 receptor greater than insulin.", "In specific embodiments, the IGF-1-receptor agonist has a binding affinity for the IGF-1 receptor greater than for the insulin receptor.", "[0042] In particular embodiments of the invention, the IGF-1-receptor agonist or antagonist has a K D for the IGF-1 receptor of less than 1 mM, less than 100 μM, less than 10 μM, less than 1 μM, less than 100 nM, less than 50 nM, less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM.", "[0043] In particular embodiments, the IGF-1-receptor agonist is not IGF-1.", "[0044] The IGF-1-receptor agonist can be a peptide in some embodiments.", "For instance, it can be a peptide of 2-60 amino acid residues, of 2-40 amino acid residues, of 2-20 amino acid residues, of 5-60 amino acid residues, of 5-40 amino acid residues, or of 5-20 amino acid residues.", "[0045] In particular embodiments of the methods using an agent that comprises an IGF-1-receptor agonist or an insulin-receptor agonist, the agent is, or comprises, an IGF-1-receptor agonist-chemotherapeutic agent conjugate or an insulin-receptor agonist-chemotherapeutic agent conjugate.", "[0046] The chemotherapeutic agent portion of the conjugates in particular embodiments is amsacrine, azacytidine, bleomycin, busulfan, capecitabine, carboplatin, carmustine, chlorambucil, cisplatin, cladribine, cyclophosphamide, cytarabine, dactinomycin, daunorubicin, decarbazine, docetaxel, doxorubicin, epirubicin, estramustine, etoposide, floxuridine, fludarabine, fluorouracil, gemcitabine, hexamethylmelamine, idarubicin, ifosfamide, irinotecan, lomustine, mechlorethamine, melphalan, mercaptopurine, mitomycin C, mitotane, mitoxantrone, oxaliplatin, paclitaxel, pemetrexed, pentostatin, plicamycin, procarbazine, ralitrexed, semustine, streptozocin, temozolamide, teniposide, thioguanine, thiotepa, topotecan, trimitrexate, valrubicin, vincristine, vinblastine, vindestine, or vinorelbine.", "[0047] Other examples of IGF-1-receptor agonists include variants of IGF-1 that activate the receptor but have reduced affinity for the soluble IGF-1 binding proteins, such as those disclosed in U.S. Pat. No. 4,876,242.", "IGF binding proteins are natural serum proteins that bind to IGF-1, holding it in circulation and extending its biological half-life.", "It may be advantageous for the IGF-1 receptor ligands of this invention to have reduced binding to the IGF-1 binding proteins, because that reduced binding would accelerate the release of the agent to bind to the IGF-1 receptors.", "Thus, in some embodiments, the IGF-1 receptor ligand or agonist has reduced affinity for soluble IGF-1 binding proteins, as compared to native IGF-1.", "[0048] One preferred variant IGF-1 for use in the methods and conjugates of the invention that has reduced binding affinity for the soluble IGF-1 binding proteins is LONG-R3-IGF-1 (Francis, G. L., et al[.", "].1992, J Mol.", "Endocrinol.", "8:213-223;", "Tomas, F. M. et al.", ", 1993, .", "J. Endocrinol.", "137:413-421) (SEQ ID NO:1).", "SEQ ID NO:1 has the sequence MFPAMPLSSL FVNGPRTLCG AELVDALQFV CGDRGFYFNK PTGYSSSRRA PQTGIVDECC FRSCDLRRLE MYCAPLKPAK SA.", "[0049] Preferably, the IGF-1 receptor ligand with reduced affinity for soluble IGF-1 binding proteins has at least 5-fold, more preferably at least 10-fold, more preferably still at least 100-fold lower binding affinity for soluble IGF-1 binding proteins than wild-type IGF-1.", "Binding affinity for the soluble IGF-1 binding proteins can be measured by a competition binding assay against labeled IGF-1 (e.g., I-125-IGF-1), using a mixture of purified IGF-1 binding proteins or rat L6 myoblast-conditioned medium (a naturally produced mixture of IGF-1 binding proteins), as described in Francis, G. L., et al.", "(1992, J Mol.", "Endocrinol.", "8:213-223);", "Szabo, L. et al.", "(1988, Biochem.", "Biophys.", "Res.", "Commun.", "151:207-214);", "and Martin, J. L. et al.", "(1986, J Biol.", "Chem.", "261:8754-8760).", "Preferably, the variant IGF-1 has an IC 50 in a competition binding assay against labeled wild-type IGF-1 for binding to soluble IGF-1 binding proteins in L6 myoblast-conditioned medium of greater than 10 nM, more preferably greater than 100 nM.", "[0050] Preferably, the variant IGF-1 with reduced affinity for soluble IGF-1 binding proteins has affinity for the IGF-1 receptor that is close to wild-type IGF-1 (e.g., less than 30-fold greater than wild-type IGF-1, more preferably less than 10-fold greater than wild-type IGF-1).", "In specific embodiments, the variant IGF-1 has an IC 50 in a competition binding assay against labeled wild-type IGF-1 for binding to IGF-1 receptors (e.g., on MCF-7 cells) of less than 50 nM, more preferably less than 10 nM, more preferably still less than 5 nM, more preferably still less than 3 nM).", "This assay is described in Ross, M. et al.", "(1989, Biochem.", "J. 258:267-272) and Francis, G. L., et al.", "(1992, J. Mol.", "Endocrinol.", "8:213-223).", "[0051] In embodiments of the invention involving use of an agent comprising an insulin-receptor agonist, the insulin-receptor agonist may be insulin.", "[0052] In particular embodiments, the insulin-receptor agonist is glycyl-L-histidyl-L-lysine-acetate (Biaglow, J. E., et al.", ", 1979, Int.", "J. Radiat.", "Oncol.", "Biol.", "Phys.", "5:1669).", "[0053] In particular embodiments of the invention, the insulin-receptor agonist is not an IGF-1-receptor agonist.", "[0054] In specific embodiments, the insulin-receptor agonist has a K D for the IGF-1 receptor of greater than 0.5 nM, greater than 1 nM, or greater than 2 nM.", "[0055] In specific embodiments, the insulin-receptor agonist has a binding affinity for the insulin receptor greater than IGF-1.", "[0056] In particular embodiments of the invention, the insulin-receptor agonist or antagonist has a K D for the insulin receptor of less than 1 mM, less than 100 μM, less than 10 μM, less than 1 μM, less than 100 nM, less than 50 nM, less than 20 nM, less than 10 nM, less than 5 nM, less than 2 nM, or less than 1 nM.", "[0057] The insulin-receptor agonist can be a peptide in some embodiments.", "For instance, it can be a peptide of 2-60 amino acid residues, of 2-40 amino acid residues, of 2-20 amino acid residues, of 5-60 amino acid residues, of 5-40 amino acid residues, or of 5-20 amino acid residues.", "[0058] In particular embodiments of the invention, the methods are used to treat lung cancer (small cell or non-small cell), prostate cancer, colorectal cancer, breast cancer, pancreatic cancer, leukemia, liver cancer, stomach cancer, ovarian cancer, uterine cancer, testicular cancer, brain cancer, non-Hodgkin's lymphoma, Hodgkin's lymphoma, Ewing's sarcoma, osteosarcoma, neuroblastoma, rhabdomyosarcoma, melanoma, head or neck cancer, or brain cancer.", "[0059] The methods of the invention may be particularly suited for treatment of low-grade non-Hodgkin's lymphoma.", "Low-grade non-Hodgkin's lymphoma is less curable than intermediate-grade or aggressive-grade non-Hodgkin's lymphoma because the cancer cells in low-grade non-Hodgkin's lymphoma divide less frequently and are thus less susceptible to radiation therapy than intermediate and aggressive-grade lymphomas.", "The agents described herein will cause the tumor cells to divide more frequently and thus be more sensitive to radiation killing.", "[0060] In particular embodiments of the methods described herein, the mammal treated by the methods is a human.", "In other embodiments, the mammal is an experimental mammal, e.g., a mouse.", "In particular embodiments, the mammal is a dog, cat, rabbit, guinea pig, or pig.", "[0061] The invention involves inducing cancer cell division by administering to a mammal afflicted with cancer an IGF-1-receptor agonist, an insulin-receptor agonist, a growth hormone receptor agonist, and/or a sugar, at approximately the time radiation administered to enhance the effectiveness of anti-cancer radiation therapy.", "In the periods between radiation therapy, it is advisable to try to prevent cancer cell division.", "Thus, the invention can involve administering in the periods between radiation therapy an IGF-1 receptor antagonist (e.g., a monoclonal antibody against the IGF-1 receptor) or an insulin-receptor antagonist (e.g., a monoclonal antibody against the insulin receptor) to the mammal.", "[0062] One embodiment involves administering a radiation-sensitizing agent described herein 0 to 12 hours before administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 0 to 12 hours before administration of radiation to the mammal.", "[0063] One embodiment involves administering a radiation-sensitizing agent described herein between 6 hours before and 6 hours after administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 6 hours before to 6 hours after administration of radiation to the mammal.", "[0064] One embodiment involves administering a radiation-sensitizing agent described herein between 3 hours before and 3 hours after administering radiation to the mammal, and administering an IGF-1 receptor antagonist (or insulin-receptor antagonist) at a time outside of 3 hours before to 3 hours after administration of radiation to the mammal.", "[0065] The invention will now be illustrated by the following non-limiting examples.", "EXAMPLES Example 1 In vitro Assays [0066] MiaPaCa (a human pancreatic cancer cell line), LnCap (a human prostate cancer cell line), H226 and A549 (two human lung cancer cell lines) are grown in monolayer cultures in McCoy's 5A medium containing 10% fetal bovine serum and buffered with 2.0 g/L sodium bicarbonate and 0.02 M Hepes, pH 7.4.", "The cells are at seeded at 6×10 4 cells per T30 flask.", "On day 3 the medium is changed.", "The cells are irradiated at either 4 days (exponential cells) or 7 days (plateau-phase cells).", "Twenty minutes before, 2 hours before, or immediately before irradiation, insulin (0.01, 0.1, or 1 μg/ml) or IGF-1 (3, 20, or 150 ng/ml) is added to the medium.", "Control cells have no added hormone.", "The cells are then irradiated with 200 rads X-rays.", "After irradiation, the cells are allowed to recover in the used medium for 60 minutes.", "[0067] The cells are then typsinized and plated in fresh medium.", "The surviving fraction of a specific number of plated cells is determined by staining colonies with methylene blue after 7-10 days of growth.", "[0068] These experiments show that at at least some concentrations and times before irradiation, both insulin and IGF increase cell killing by radiation in plateau-phase cells.", "[0069] Exponential phase cells are also sensitized to radiation by both insulin and IGF-1.", "[0070] Exponential-phase and plateau-phase cells are then treated with insulin and IGF-1 separately and together at their experimentally determined optimal concentrations immediately before, 15 minutes before, and 2 hours before irradiation with a range of radiation doses.", "Again, the cells are trypsinized and plated, and the percent surviving is determined.", "It is found that the effect of both hormones together is greater than either alone in enhancing killing.", "[0071] Exponential- and plateau-phase cells are then treated with insulin at the optimal concentration in combination with 30 mM glucose.", "It is found that the addition of glucose enhances radiation killing above that observed with insulin alone.", "Example 2 In vivo Assays [0072] LnCap, MiaPaCa, H226, and A549 cells are grown in culture.", "Cells are harvested using 0.25% trypsin, washed, suspended in Dulbecco's PBS, and counted.", "1×10 6 cells are injected subcutaneously into the hind thigh of male nude mice.", "Tumors are grown to 250 mm 3 in ˜21 days.", "Tumors are measured with a caliper, and the tumor size is calculated by the formula a 2 b/2, where a and b are the shorter and longer diameters of the tumor, respectively.", "[0073] When the tumors reach 250 mm 3 , the mice are treated with insulin (5 or 40 μg/kg), IGF-1 (5 or 100 μg/kg) or insulin+glucose (5 g glucose/kg), or growth hormone (50 or 500 μg/kg), or saline control 30 minutes before radiation treatment.", "[0074] The mice are anesthetized immediately before radiation treatment, and then the tumor-bearing leg is irradiated with X-rays at 1.4 Gy/minute, receiving a dose of 15 Gy.", "[0075] The growth of tumor volume in the mice after irradiation is followed for 3 weeks.", "[0076] These experiments will show insulin, insulin+glucose, IGF-1, and growth hormone all enhance the effectiveness of radiation therapy.", "[0077] All patents, patent documents, and other references cited herein are incorporated by reference." ]
CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional of application Ser. No. 10/393,243 filed Mar. 19, 2003, which claims the benefit of priority from U.S. provisional patent application No. 60/365,678, filed Mar. 19, 2002. FIELD OF THE INVENTION The present invention relates to joint replacement and, more particularly, to a system and method for prosthesis fitting and balancing in joints. BACKGROUND OF THE INVENTION Some medical conditions can result in the degeneration of a human joint, causing a patient to consider and ultimately undergo joint replacement surgery. While joint replacement surgery is well known in the art, the decision to undergo such a procedure may be a difficult one, as the long-term success of the surgery oftentimes relies upon the skill of the surgeon and may involve a long, difficult recovery process. The materials used in a joint replacement surgery are designed to enable the joint to move just like a normal joint. The prosthesis is generally composed of a metal piece that fits closely into and bears on a corresponding plastic component. The plastic component is typically supported on another metal piece. Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene. Plastic bone cement may be used to anchor the prosthesis into the bone, however, the prosthesis may be implanted without cement when the prosthesis and the bone are designed to fit and lock together directly. To undergo the operation, the patient is given an anesthetic while the surgeon replaces the damaged parts of the joint. For example, in knee replacement surgery, the damaged ends of the bones (i.e., the femur and the tibia) and the cartilage are replaced with metal and plastic surfaces that are shaped to restore knee movement and function. In another example, to replace a hip joint, the damaged ball (the upper end of the femur) is replaced by a metal ball attached to a metal stem fitted into the femur, and a plastic socket is implanted into the pelvis, replacing the damaged socket. Although hip and knee replacements are the most common, joint replacement can be performed on other joints, including the ankle, foot, shoulder, elbow and fingers. As with all major surgical procedures, complications can occur. Some of the most common complications are typically thrombophlebitis, infection, stiffness, and loosening. While thrombophlebitis (i.e., vein inflammation related to a blood clot) and infection are oftentimes treated medically, stiffness and loosening may require additional surgeries. One technique utilized to reduce the likelihood of stiffness and loosening relies upon the skill of the surgeon to align and balance the replacement joint along with ligaments and soft tissue during surgery. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a computer system illustrating an example environment of use for the disclosed system; FIG. 2 is a block diagram of a joint prosthesis fitting and balancing system; FIG. 3 is a front perspective view of an embodiment of a prosthesis fitted within a human knee; FIG. 4 is a top perspective view of an embodiment of a spacer of the system of FIG. 2 ; FIG. 5 is a bottom perspective view of the spacer of FIG. 4 ; FIG. 6 is a side perspective view of an embodiment of a portion of the system of FIG. 2 ; FIG. 7 is a front perspective view of an embodiment of a portion of the system of FIG. 2 ; FIG. 8 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at zero degrees; FIG. 8A is a graph plotting pressure readings in the prosthesis of FIG. 8 ; FIG. 9 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at thirty degrees; FIG. 9A is a graph plotting pressure readings in the prosthesis of FIG. 9 ; FIG. 10 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at sixty degrees; FIG. 10A is a graph plotting pressure readings in the prosthesis of FIG. 10 ; FIG. 11 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during flexion of the prosthesis; FIG. 12 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during extension of the prosthesis; FIG. 13 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ; FIG. 14 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ; FIG. 15 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ; FIG. 16 is a top perspective view of an embodiment of a jig which may be used in conjunction with the system of FIG. 2 ; FIG. 17 is a diagrammatic view of a wireless graphical hand-held output display in accordance with one possible form of the present invention; and FIG. 18 is a block diagram of an exemplary data collection modeling/analysis display scheme. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A block diagram of an example computer system 10 is illustrated in FIG. 1 . The computer system 10 may be a personal computer (PC) or any other computing device capable of executing a software program. In an example, the computer system 10 includes a main processing unit 12 powered by a power supply 13 . The main processing unit 12 illustrated in FIG. 1 includes one or more processors 14 electrically coupled by a system interconnect 16 to one or more memory device(s) 18 and one or more interface circuits 20 . In an example, the system interconnect 16 is an address/data bus. Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than busses may be used to connect the processor(s) 14 to the memory device(s) 18 . For example, one or more dedicated lines and/or a crossbar may be used to connect the processor(s) 14 to the memory device(s) 18 . The processor(s) 14 may include any type of well known microprocessor, such as a microprocessor from the Intel Pentium™ family of microprocessors. The illustrated main memory device 18 includes random access memory such as, for example, dynamic random access memory (DRAM), or static random access memory (SRAM), but may also include non-volatile memory. In an example, the memory device(s) 18 store a software program which is executed by one or more of the processors(s) 14 in a well known manner. The interface circuit(s) 20 are implemented using any type of well known interface standard, such as an Ethernet interface and/or a Universal Serial Bus (USB) interface. In the illustrated example, one or more input devices 22 are connected to the interface circuits 20 for entering data and commands into the main processing unit 12 . For example, an input device 22 may be a keyboard, mouse, touch screen, track pad, track ball, isopoint, and/or a voice recognition system. In the illustrated example, one or more displays, printers, speakers, and/or other output devices 24 are also connected to the main processing unit 12 via one or more of the interface circuits 20 . The display 24 may be a cathode ray tube (CRT), a liquid crystal display (LCD), or any other type of display, such as a hand-held display 500 as shown in FIG. 17 . The display 24 may generate visual indications of data generated during operation of the main processing unit 12 . For example, the visual indications may include prompts for human operator input, calculated values, detected data, etc. The illustrated computer system 10 also includes one or more storage devices 26 . For example, the computer system 10 may include one or more hard drives, a compact disk (CD) drive, a digital versatile disk drive (DVD), and/or other computer media input/output (I/O) devices. The illustrated computer system 10 may also exchange data with other devices via a connection to a network 118 . The network connection may be any type of network connection, such as an Ethernet connection, digital subscriber line (DSL), telephone line, coaxial cable, etc. The network 118 may be any type of network, such as the Internet, a telephone network, a cable network, and/or a wireless network. An example system for prosthesis fitting and balancing in joints is illustrated in FIG. 2 . In one embodiment, the system includes a prosthesis 30 , a joint angle sensor 36 , a ligament tension sensor 38 , an analysis program 40 , the main unit 12 , the one or more storage devices 26 , and the display 24 . As will be described in detail below, the artificial joint may comprise a femoral component 32 , a tibial tray 58 , and a spacer 34 with one or more imbedded sensors 35 . Any or all of the sensors 35 , 36 , 38 may be implemented by conventional sensor technology, including commercially available pressure sensors, tension sensors, and angle sensors. Furthermore, any or all of the storage device 26 , and the analysis program 40 may be implemented by conventional electronic circuitry, firmware, and/or by a microprocessor executing software instructions in a well known manner. However, in the illustrated example, the analysis program 40 is implemented by software stored on the memory 18 and executed by the processor 14 , while the storage device 26 may be implemented by database server software stored on the memory 18 , and executed by the processor 14 to physically store data on a hard drive. In addition, a person of ordinary skill in the art will readily appreciate that certain modules in the apparatus shown in FIG. 2 may be combined or divided according to customary design constraints. Still further, one or more of the modules may be located external to the main processing unit 12 . Turning to FIG. 3 , there is shown an example of the prosthesis 30 as used in conjunction with the replacement of a human knee 50 . In general, the human knee 50 comprises a femur 52 , a patella 53 , a tibia 54 , a plurality of ligaments (not shown), and a plurality of muscles (not shown). The prosthesis 30 generally comprises two parts, the femoral component 32 and a tibial component 56 . Additionally, the tibial component 56 is typically made up of two parts, the metal tibial tray 58 that is attached directly to the tibia 54 and the spacer 34 that provides the bearing surface. It will be understood that the while in the disclosed embodiment the tibial component 56 is comprised of separate components, the spacer 34 and the metal tibial tray 58 may be integrally formed. The materials used in a joint replacement surgery are designed to enable the joint to mimic the behavior or a normal knee joint. In the illustrated embodiment, the femoral component 32 is a metal piece, shaped similar to the end of the femur and fitting closely into a corresponding plastic spacer 34 . Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene. Other suitable materials may now exist or may be developed in the future. Plastic bone cement may be used to anchor the prosthesis 30 into the bones 52 , 54 , however, the prosthesis 30 may be implanted without cement when the prosthesis 30 and the bones 52 , 54 are designed to fit and lock together directly. A cemented prosthesis 30 is held in place by a type of epoxy cement that attaches the metal to the bones 52 , 54 . An uncemented prosthesis 30 has a fine mesh of holes on the surface that allows the bones 52 , 54 to grow into the mesh and attach the prosthesis 30 to the bones 52 , 54 . Referring now to FIGS. 4 and 5 , there is illustrated an example spacer 34 which may be used in conjunction with an embodiment of the system of FIG. 2 . The spacer 34 includes a pair of opposed faces 60 , 62 and an elongated side edge 64 . The face 60 comprises a pair of condyle recesses 68 , 66 , shaped to closely match or otherwise accommodate the shaped end of the femoral component 32 . The face 60 may also comprise an extension 70 which may slidably engage a groove 71 in the femoral component 32 and prevent lateral movement between the spacer 34 and the femoral component 32 , while allowing the two pieces to rotate relative to each other in a predefined range of motion similar to a biological knee, for example, between zero degrees (0°), i.e., extension, and ninety degrees (90°), i.e., flexion. The contact between the femoral component 32 and the spacer 34 will produce deformations in the two surfaces in contact, which may be measured by the sensors 35 embedded in the spacer 34 . The sensed deformation may cause an output to be created by the sensors 35 . The opposite face 62 includes an elevated face 72 . The elevated face 72 and the face 62 cooperate to form a snap-fit connection with the tibial tray 58 as is well known in the art. It will be noted that connection between the tibial tray 58 and the spacer 34 may vary according to known design variations. For instance, the elevated face 72 and the face 62 may be substantially coplanar and may be cemented onto the tibial tray 58 . In the illustrated embodiment of FIG. 5 , the elevated face 72 is illustrated with a plurality of recesses 74 . The recesses 74 are milled in the face 72 of the polyethylene and have a cross section sized to accept sensors 35 , thereby enabling the sensors 35 embedded in the spacer 34 . Since the sensors 35 are responsive to the deformation of the spacer 34 , the depth of the recesses 74 may be chosen to minimize the impact on the deformation characteristics of the spacer 34 , as well as to ensure an accurate reading based on the sensitivity of the sensor 35 . For example, in the illustrated embodiment, the recesses 74 have a cross section of appropriately dimensioned to accept a strain sensor marketed by Omega Engineering, Inc., of Stanford, Conn. In one embodiment, the recesses are arranged in an array and include a bar-shaped micro miniature strain gage (sensor 35 ) of approximate dimension 1 mm×0.5 mm×0.15 mm. The strain gage is responsive to the deformation of curvature with a maximum strain of 3000μ. Furthermore, the strain gage may provide data in a real-time, or near real-time fashion, allowing for intraoperative analysis of the data. A person of ordinary skill in the art will readily appreciate that other sensors may be used to sense the deformation of the spacer 34 . For example, a single sensor, or an array of sensors may be used to sense the deformation of the spacer 34 . Once the sensor 35 is placed in the recesses 74 , the recesses may be filled with a plug of the same, or similar, material as the spacer 34 , to further minimize the impact on the deformation characteristics of the spacer 34 . The recess plug may be, for example, glued in place, or held by an interference fit. Of course, a person of ordinary skill in the art will readily appreciate that any number of recesses 74 and sensors 35 may be utilized. Moreover, the dimensions of the recesses may vary greatly, depending upon the characteristics of the spacer 34 , the sensor 35 , and/or the desired sensitivity. Still further, it will be appreciated that the sensors 35 may be embedded within the spacer 34 utilizing any known or yet to be developed manufacturing method, including direct insertion during the molding process, as well as insertion utilizing a transverse cut in the spacer 34 . The spacer 34 illustrated in FIG. 5 includes a plurality of sensors 35 electrically coupled by a system interconnect (not shown) to one or more transceiver device(s) 76 . In the example, the system interconnect is a plurality of wires (not shown) transversely carried through the spacer 34 to the transceiver device(s) 76 . Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than wires may be used to connect the sensors 35 to the transceiver devices(s) 76 . For example, one or more wireless connections may be used to connect the sensors 35 to the transceiver device(s) 76 . In the illustrated embodiment, the transceiver device(s) 76 is embedded within another recess 77 within the elevated face 72 of the spacer 34 , however, it will be understood that the transceiver may be located in any location, including external to the spacer 34 . In one embodiment, the transceiver device(s) 76 is a self powered, 5 channel input transceiver having approximate dimensions of 1.46 cm×3.05 cm×0.65 cm. The transceiver has a sample rate of 150 samples per second and is powered by a 3.1 volt minimum, 7 volt maximum, 13.8 DC battery. Additionally, the transceiver may contain a memory for storing sensor data. In operation, the transceiver device 76 is adapted to receive, as an input, multiple sensor outputs created by each of the sensors 35 in response to the deformation of the spacer 34 . The transceiver device 76 is further adapted to convert the multiple sensor inputs to a serial data stream and transmit the data stream, via wired or wireless connection, to the main unit 12 . The transceiver devices 76 is preferably a single battery powered transceiver capable of wireless transmission, however, it may be any type of transceiver known or yet to be developed, such as a magnetically powered transceiver. Furthermore, it will be appreciated by one of ordinary skill in the art that the transceiver device(s) 76 and the sensors 35 may be combined or divided according to customary design constraints. Still further, the spacer 34 with embedded sensors 35 may be designed to be substantially permanently attached to the tibial tray 58 , i.e., bioengineered to remain in the prosthesis 30 after surgery, or it may be temporarily attached to the tibial tray 58 , i.e., to be used only during the actual replacement surgery to gather data and replaced by a substantially permanent spacer. In the disclosed example, this is aided by the fact that the sensors 35 , etc. are fully encapsulated in the spacer 34 . Referring now to FIGS. 6 and 7 , there is illustrated a human knee exposed for surgery with the prosthesis 30 and sensors 35 , 36 , 38 in place. Specifically, the femoral component 32 is attached to the femur 52 , and the tibial component 56 is attached to the tibia 54 . The spacer 34 and embedded sensors 35 are in place between the femoral component 32 and the tibial tray 58 . In the illustrated embodiment, a plurality of ligament tension sensors 38 are attached to external knee ligaments, such as, for example, the medial cruciate ligament and the lateral cruciate ligament. Additionally, the joint angle sensor 36 may be attached to the surface of the human knee 50 . The ligament tension sensors 38 may be any commercially available tension sensors such as one marketed by Omega Engineering, Inc., of Stanford, Conn. The ligament tension sensor 38 is responsive to the tension of the ligament to which it is attached, and is adapted to produce an output in response to the sensed tension. The ligament tension sensor 38 may also comprise a transceiver (not shown) similar to the above-described transceiver device 76 . The data output from the ligament tension sensor 38 may thereby be transmitted to the main unit 12 . The joint angle sensor 36 may be any commercially available angle sensor such as—one marketed by Omega Engineering, Inc., of Stanford, Conn. The joint angle sensor 36 is responsive to the range of motion of the prosthesis 30 , and is adapted to produce an output representative of the joint angle. The joint angle sensor 36 may also comprise a transceiver (not shown) similar to the above-described transceiver device 76 . The data output from the joint angle sensor 36 may thereby be transmitted to the main unit 12 . As will be appreciate by one of ordinary skill in the art, the sensors 35 , 36 , 38 may be used in any number of combinations, depending upon the desired data collection strategy. For example, a practitioner may only be interested in the pressure between the spacer 34 and the femoral component 32 when the prosthesis is fully extended, and may therefore, only utilize the sensor 35 and the joint angle sensor 36 . Once all the desired sensors 35 , 36 , 38 are in place, it may be desirable to partially close the incision to evaluate the prosthesis 30 range of motion during flexion and extension. The surgeon may then flex the prosthesis 30 through its normal range of motion. The outputs from the sensors 35 , 36 , 38 are transmitted to the main unit 12 , wherein they may be captured by the analysis program 40 . In one embodiment, the analysis program 40 may be, for example, LabVIEW™ data acquisition software marketed by National Instruments Corp., of Austin, Tex. and commercially available. The analysis program 40 may display the data in a variety of formats on the display(s) 24 , as will be described below. The analysis program 40 may be adapted to transmit the acquired data to the database server software stored on the memory 18 , and executed by the processor 14 to physically store data on a hard drive. In one embodiment, as shown by FIGS. 8 through 10A , the sensor 35 , 38 measurements are captured by the analysis program 40 and displayed as a pressure distribution graph. Specifically, referring to FIGS. 8 and 8A , the analysis program 40 displays a three dimensional pressure distribution graph 100 , in pounds per square in (lb/in 2 ) when the prosthesis 30 is in the zero degree (0°) extension position (illustrated by FIG. 8 ). As described in detail above, the pressure distribution graph is representative of the sensed pressure on the spacer 34 by the femoral component 32 . The illustrative pressure distribution graph 100 displays six regions of pressure sensor readings, namely an anterior 102 , 104 , a middle 106 , 108 , and a posterior region 110 , 112 , duplicated on both the medial and lateral portions of the spacer 32 respectively. It will be understood that while six regions 102 , 104 , 106 , 108 , 110 , 112 are displayed, each region may be comprised of any number of individual sensor readings, including multiple readings per region. Referring to FIGS. 9 and 9A , and FIGS. 10 and 10A , the analysis program 40 displays a three dimensional pressure distribution graph 120 , 140 in pounds per square in (lb/in 2 ) when the prosthesis 30 is in the thirty degree (30°) extension position (illustrated by FIG. 9 ), and when the prosthesis 30 is in the sixty degree (60°) extension position (illustrated by FIG. 10 ). As described in above, the illustrative pressure distribution graphs 120 , 140 display six regions of pressure sensor readings, namely an anterior 102 , 104 , a middle 106 , 108 , and a posterior region 110 , 112 , duplicated on both the medial and lateral portions of the spacer 32 respectively. The graphical pressure distribution graphs may allow the physician to adjust their surgical or medical procedures by examining the pressure within the prosthesis 30 at certain angles. For example, the physician may recognize, either by experience or knowledge of design constraints, that the medial anterior pressure region 102 of FIG. 8A is slightly elevated and may adjust the prosthesis 30 accordingly. Additionally, the analysis program 40 may provide the physician with the tension readings provided by the ligament tension sensors 38 (not shown) to aid the physician in determining whether, based upon the knowledge and skill of the surgeon, the ligaments should be adjusted. In yet another embodiment, the analysis program 40 may be adapted to compare the acquired data to the data stored by the database server software on the hard drive. For example, upon the collection of a number of trials of empirical data, the stored data may be statistically analyzed (either by the analysis program 40 , or another external program) to form suggested pre-determined pressure criteria, i.e., upper and lower limits, to aid the physician in recognizing potential elevated pressure readings. The suggested pre-determined pressure criteria may define statistically sound thresholds and allowable limits under certain conditions, and may be constantly adjusted as more information becomes available in the database. In yet another embodiment, as shown by FIGS. 11 and 12 , the sensor 35 , 38 measurements are captured by the analysis program 40 and displayed as a pressure graph as a function of joint angle. Specifically, referring to FIGS. 11 and 12 , the analysis program 40 displays a two dimensional pressure graph 200 , 220 in pounds per square inch (lb/in 2 ) when the prosthesis 30 is moving in the flexion range of motion ( FIG. 11 ) and when the prosthesis 30 is moving in the extension range of motion ( FIG. 12 ). Again, as described in detail above, the pressure distribution graph is representative of the sensed pressure on the spacer 34 by the femoral component 32 . FIG. 11 illustrates a graph plotting the six sensor regions 102 104 , 106 , 108 , 110 , 112 marked by their respective reference numerals versus joint angle, wherein the prosthesis 30 is moving in flexion. FIG. 12 illustrates a graph plotting the six sensor regions 102 104 , 106 , 108 , 110 , 112 marked by their respective reference numerals versus joint angle, wherein the prosthesis 30 is moving in extension. As the graphs of FIGS. 11 and 12 show, the pressure on each region varies according to joint angle, providing the physician with a graphical understanding of the mechanics of the prosthesis 30 and allowing the physician to adjust their surgical or medical procedures by examining the pressure within the prosthesis 30 over the full range of motion. It will be understood that the sensor 35 , 36 , 38 measurements captured by the analysis program 40 and may be displayed in any number of various ways, including, raw data dumps, and as graphs, similar to those disclosed above. For example, in another embodiment (not shown), the analysis program 40 may display a pressure graph as a function of ligament tension. It will be appreciated, however, that the example graphs above are merely illustrative, and are no way limiting. In still another embodiment, the outputs from the sensors 35 , 36 , 38 may be transmitted to the main unit 12 , wherein they may be captured by another embodiment of the analysis program 40 which may be, for example, a finite element analysis program (“FEA” program). An example of an FEA program is the ANSYS Finite Element Analysis software program marketed by ANSYS Inc. located in Canonsburg, Pa., and commercially available. The FEA analysis program 40 is flexible, and may display the data in a variety of formats on the display(s) 24 . In one embodiment, as shown by FIGS. 13 through 15 , the sensor 35 , 38 measurements are captured by the FEA analysis program 40 and displayed as both a pressure distribution graph, and as a pressure topography graph. Specifically, referring to FIG. 13 , the FEA analysis program 40 displays a three dimensional pressure topography graph 300 , in kilopascal (kPa) when the prosthesis 30 is in the zero degree (0°) position. Similar to the other embodiments, for example a pressure distribution graph 310 , and as described in detail above, the pressure topography graph 300 is representative of the sensed pressure on the spacer 34 by the femoral component 32 at a specific angle. Unlike the pressure distribution graph 310 , however, the illustrative pressure topography graph 300 displays the pressure in relationship to the modeled spacer 34 , allowing the practitioner to identify the location of the pressure points in spatial relation to the spacer 34 used. Referring to FIGS. 14 and 15 , the analysis program 40 displays a three dimensional pressure topography graph 320 , 340 in kilopascal (kPa) when the prosthesis 30 is in the forty degree (40°) position (illustrated by FIG. 14 ), and when the prosthesis 30 is in the ninety degree (90°) position (illustrated by FIG. 15 ). As described in above, the illustrative pressure topography graphs 320 , 340 displays pressure in relationship to the modeled spacer 34 , as opposed to the six region pressure distribution graphs 330 , 350 . Referring now to FIG. 16 , there is illustrated a jig 400 which may be used in the operative environment of FIGS. 6 and 7 , or alternatively, in a testing environment, such as cadaver testing, or the like. The jig 400 is arranged to control the flexion of the prosthesis 30 in the intra operative environment is such a way that a number of variables may be controlled. For example, the jig may control, for instance, the rate of flexion and extension, the total range of motion, and the axis of motion, etc., in such a manner that the user may experience consistent and reproducible results when testing various aspects of the prosthesis 30 . It will be noted that while the above description relates to an embodiment of a human a prosthetic, it will be readily understood that the principles of the present invention may be applied to any type of replacement joint, as well as any living organism. For example, the sensors 35 of the present embodiment may be utilized to replace a hip joint, or other joint, including the ankle, foot, shoulder, elbow and fingers. For instance, in hip joint replacement, the damaged ball (the upper end of the femur) is replaced by a metal ball attached to a metal stem fitted into the femur, and a plastic socket is implanted into the pelvis, replacing the damaged socket. The sensors 35 may be embedded within the plastic socket (or other location) to provide the practitioner with data related to the contact between the metal stem and the socket. It will be further understood that the main unit 12 may be arranged to receive input from an MRI, CAT scan, X-ray, and/or other diagnostic device to feed the analysis program 40 with that input. The analysis program 40 may then convert that input to a model of the patient's knee. The model may reduce or eliminate the need for conventional intermedullar rods conventionally used to determine the specific of the tibial and femoral cut down, such as location, angle, etc. One example of these data collection, finite element analysis and/or joint modeling steps, along with there respective graphical outputs or displays is shown in FIG. 18 . A system and method according to the disclosed example may serve to improve longevity and function of Total Knee Arthroplasty (TKA). The accurate balancing of the forces acting on the joint in a total knee arthroplasty results in proper component placement and proper tensioning of the ligamentous structures that cross the knee joint. When a knee arthroplasty is properly balanced, stresses are evenly distributed in the articulating components through a full range of motion. Functionally poor ligament balance, which can create instability causing acute subluxation or dislocation of the total knee components, may be reduced or eliminated. On the other hand, tight ligaments can produce stiffness limiting or precluding knee motion. More subtle discrepancies in ligament balancing create abnormally high peak stresses in the articular components and at the bone prosthesis interface causing catastrophic failure of polyethylene tibial components or mechanical loosening at the bone cement interface. Additionally, undue stresses can increase component wear, which is deleterious because the wear particles are phagocytized by macrophages initiating an inflammatory cascade that stimulates osteoclast activity. This causes osteolysis with bone loss and degradation of the bone implant interface and eventual loosening. In accordance with the disclosed example, the necessary experimental and analytical tools to quantify and standardize balancing of the knee joint during TKA may be developed. Additional data may be collected from cadaver total knee arthroplasty experiments in order to correlate stress measurements with abnormalities of ligamentous balance and component position. Using the system disclosed herein, as the knee is flexed through a complete range of motion the pressures may be collected in real time or in near real time. While the knee is flexed tension will be measured in the structures bridging the joint to measure the effect of increased tension on the stress values. Data may also be obtained on the effect of component malposition on the stresses across the knee. The data obtained may be used to create a mathematical model for knee arthroplasty. For example, a clinical advisory board of orthopedic surgeons may be established to define possible criteria needed to achieve acceptable conformity in a balanced knee. A rough paradigm may be developed to aid in guiding the surgeon in interpretation of stress data obtained during knee arthroplasty. Stress data may be obtained during total knee implantation intraoperatively using a wireless sensory device. The paradigm may be tested and fine tuned so that stress data can guide the surgeon in achieving proper balance when performing TKA. The disclosed system may further aid in investigating the force requirements from the collateral segments and how they influence the pressure/contact between the femoral and tibial component during flexion-extension. The effects of pressure on the wear on the polyethylene component of the biomechanics of the knee may be readily studied, threshold limits of pressure values deemed acceptable to balance the knee after TKA may be developed. An analytical dynamical model of the knee will used to analyze the experimental data. A dynamic model of the knee depicting all the intricate details such as contact in the presence of active forces, patella, collateral ligaments, attachment points, bone density, design characteristic of the prosthesis, interface between bone and femoral-tibial components, may be developed using known methodologies. In this phase of the study pressure profiles will be created corresponding to specific increments of misalignment. This synthesis will validate the information with the concurrent experiment that has implemented the sensor technology. An advisory board will be set up where clinicians and surgeons will set up threshold for contact pressure in the TKA. Based on precalibrated values of experimental study, the surgeon can then do proper ligament release or component exchange to bring the values within acceptable limits. Eventually, this will be taken as guidelines which will allow a precision fit in the operating room without any reliance on the experience of the surgeon. Effectively this study will lead in achieving a higher level of joint mobility performance in arthritic patient. Ultimately, not only a better tracking mechanism of wear and performance of the TKA will be developed but also the clinician's performance during the surgery will be evaluated through the quantitative feedback he receives. Based on the results a special jig 400 will be designed to immobilize the femur while allow free motion of the tibia and quadriceps mechanism. The components will then be implanted and the knee will be placed in the special jig 400 . A computerized winch will pull on the quadriceps tendon duplicating the force and the direction of the quadriceps muscle. The rectus femoris and vastus intermedius will be tied together and loaded with a 30-N weight, the rectus medialis will be loaded with 25-N weight and the vastus lateralis will be loaded with 20-N. Finally, a high precision potentiometer (shape sensor) will be used to measure the joint angle. The knee will then be flexed and extended from 0 to 9° degrees. A distribution of contact pressure will be recorded as a function of angle. The leg will also be outfitted with an angle sensor on the side of the knee in order to measure joint angle. The sensors will allow readings of stress and tension in real time as the knee is brought through the complete flexion cycle. The effect of each particular reefing on peak joint stresses will be measured and abnormal tension in the shortened ligament will be correlated with peak joint stresses through the flexion cycle. Finally the components will be placed in abnormal positions of valgus, varus, flexion and extension and the pressures again measured through the flexion cycle. A Sample Experimental Procedure: An experimental knee replacement procedure was performed on a mock human knee 50 . Once the experimental knee replacement surgery was performed, a traditional spacer was removed and replaced with one that had six pressure sensors 35 . the sensors 35 and the main unit 12 were coupled through the use of wires. The knee 50 was stitched with the wires running through the wound. The femur 52 was immobilized with the jig 400 and the quadriceps were loaded. The joint angle sensors 36 were put in place. The knee 50 was then extended and flexed through the normal range of motion many times. The rate pf flexion was approximately 20 degrees per second. Caution was taken in order not to apply external varus or valgus stress. The cycle of extension and flexion was repeated many times and recordings were averaged. A finite element model was created by scanning the actual spacer 34 with a laser micrometer and importing the geometry into a computer file. Using Autocad, a three dimensional file was refined and then exported in to an ANSYS compatible format. The current ANSYS spacer model has over 23,000 elements, which have 20 nodes each and a tetrahedral shape. On the surface of each condyle 66 , 68 , twelve hundred and fifty nine (1259) nodes resided. These nodes are responsible for the application of all pressure and forces to the model while the bottom surface is constrained to have zero displacement. The spacer model was designed so that data could be inputted into the model easily using data from the output sensors 35 . ANSYS was then used to generate the necessary plots of stress—both principal stresses and von-Mises stress plots of the deformation of the tibia component were be displayed as function of time variant pressure do to tibiofemoral contact. The contact pressures at each sensor 35 was displayed for knee extension and flexion. The joint angle range of motion varied from roughly ninety degree (90°) to zero degrees (0°). During knee extension, very small contact forces were recorded while the knee was between ninety degrees (90°) and fifty degrees (50°). For example, one sensor showed activity between fifty degrees (50°) and twenety five degrees (25°) with a maximum of 40 psi at approximately 35°. Another sensor recorded a maximum at sixteen degrees (16°) with pressure of 110 psi. During flexion, contact pressures were recorded with slightly larger magnitudes. For example one sensor, which recorded no more than 3-psi during extension, recorded 10-psi at around seventy five degrees (75°) during flexion. Similarly, another sensor which recorded a maximum at thirty five degrees (35°) during extension, recorded a maximum while at twenty five degrees (25°) during flexion. As a result, it may be concluded that for this experiment, forces on the medial and lateral condyle were not balanced in phase or magnitude. This would suggest a varus-valgus unstable knee. The high pressure recorded at the extended end of the graph suggested a joint that is too tight. Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the forgoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the system may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which are within the scope of any subsequent claims is reserved.
A system and method for prosthesis fitting in joints comprising an artificial condyle and a spacer which cooperates with the condyle to form an artificial joint. The spacer embedded with at least one sensor which is responsive to a force generated between the condyle and the spacer. The artificial joint is adapted to move between a flexed position and an extended position defining a range of motion. The sensor is responsive to the force and generates an output representative of that force. The output is transmitted, either wirelessly or other, to a processor which utilizes an analysis program to display a representation of the forces applied. A practitioner utilizing the displayed analysis may intraoperatively determine the adjustments and balancing required within the artificial joint. The system may also utilize a ligament tension sensor which generates generates data representative of tension on a ligament of the artificial joint, and a joint angle sensor responsive to the range of motion of the artificial joint. The processor may be adapted to store the outputted sensor data to provide the practitioner with statistically relevant historical data.
Condense the core contents of the given document.
[ "CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional of application Ser.", "No. 10/393,243 filed Mar. 19, 2003, which claims the benefit of priority from U.S. provisional patent application No. 60/365,678, filed Mar. 19, 2002.", "FIELD OF THE INVENTION The present invention relates to joint replacement and, more particularly, to a system and method for prosthesis fitting and balancing in joints.", "BACKGROUND OF THE INVENTION Some medical conditions can result in the degeneration of a human joint, causing a patient to consider and ultimately undergo joint replacement surgery.", "While joint replacement surgery is well known in the art, the decision to undergo such a procedure may be a difficult one, as the long-term success of the surgery oftentimes relies upon the skill of the surgeon and may involve a long, difficult recovery process.", "The materials used in a joint replacement surgery are designed to enable the joint to move just like a normal joint.", "The prosthesis is generally composed of a metal piece that fits closely into and bears on a corresponding plastic component.", "The plastic component is typically supported on another metal piece.", "Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene.", "Plastic bone cement may be used to anchor the prosthesis into the bone, however, the prosthesis may be implanted without cement when the prosthesis and the bone are designed to fit and lock together directly.", "To undergo the operation, the patient is given an anesthetic while the surgeon replaces the damaged parts of the joint.", "For example, in knee replacement surgery, the damaged ends of the bones (i.e., the femur and the tibia) and the cartilage are replaced with metal and plastic surfaces that are shaped to restore knee movement and function.", "In another example, to replace a hip joint, the damaged ball (the upper end of the femur) is replaced by a metal ball attached to a metal stem fitted into the femur, and a plastic socket is implanted into the pelvis, replacing the damaged socket.", "Although hip and knee replacements are the most common, joint replacement can be performed on other joints, including the ankle, foot, shoulder, elbow and fingers.", "As with all major surgical procedures, complications can occur.", "Some of the most common complications are typically thrombophlebitis, infection, stiffness, and loosening.", "While thrombophlebitis (i.e., vein inflammation related to a blood clot) and infection are oftentimes treated medically, stiffness and loosening may require additional surgeries.", "One technique utilized to reduce the likelihood of stiffness and loosening relies upon the skill of the surgeon to align and balance the replacement joint along with ligaments and soft tissue during surgery.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a computer system illustrating an example environment of use for the disclosed system;", "FIG. 2 is a block diagram of a joint prosthesis fitting and balancing system;", "FIG. 3 is a front perspective view of an embodiment of a prosthesis fitted within a human knee;", "FIG. 4 is a top perspective view of an embodiment of a spacer of the system of FIG. 2 ;", "FIG. 5 is a bottom perspective view of the spacer of FIG. 4 ;", "FIG. 6 is a side perspective view of an embodiment of a portion of the system of FIG. 2 ;", "FIG. 7 is a front perspective view of an embodiment of a portion of the system of FIG. 2 ;", "FIG. 8 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at zero degrees;", "FIG. 8A is a graph plotting pressure readings in the prosthesis of FIG. 8 ;", "FIG. 9 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at thirty degrees;", "FIG. 9A is a graph plotting pressure readings in the prosthesis of FIG. 9 ;", "FIG. 10 is a side view of an embodiment of a prosthesis fitted within a human knee, wherein the knee is bent at sixty degrees;", "FIG. 10A is a graph plotting pressure readings in the prosthesis of FIG. 10 ;", "FIG. 11 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during flexion of the prosthesis;", "FIG. 12 is a graph plotting pressure readings as a function of joint angle of a prosthesis of FIG. 2 during extension of the prosthesis;", "FIG. 13 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ;", "FIG. 14 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ;", "FIG. 15 is a topographical pressure graph plotting pressure readings against a three dimensional rendering of an embodiment of a spacer of FIG. 2 ;", "FIG. 16 is a top perspective view of an embodiment of a jig which may be used in conjunction with the system of FIG. 2 ;", "FIG. 17 is a diagrammatic view of a wireless graphical hand-held output display in accordance with one possible form of the present invention;", "and FIG. 18 is a block diagram of an exemplary data collection modeling/analysis display scheme.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A block diagram of an example computer system 10 is illustrated in FIG. 1 .", "The computer system 10 may be a personal computer (PC) or any other computing device capable of executing a software program.", "In an example, the computer system 10 includes a main processing unit 12 powered by a power supply 13 .", "The main processing unit 12 illustrated in FIG. 1 includes one or more processors 14 electrically coupled by a system interconnect 16 to one or more memory device(s) 18 and one or more interface circuits 20 .", "In an example, the system interconnect 16 is an address/data bus.", "Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than busses may be used to connect the processor(s) 14 to the memory device(s) 18 .", "For example, one or more dedicated lines and/or a crossbar may be used to connect the processor(s) 14 to the memory device(s) 18 .", "The processor(s) 14 may include any type of well known microprocessor, such as a microprocessor from the Intel Pentium™ family of microprocessors.", "The illustrated main memory device 18 includes random access memory such as, for example, dynamic random access memory (DRAM), or static random access memory (SRAM), but may also include non-volatile memory.", "In an example, the memory device(s) 18 store a software program which is executed by one or more of the processors(s) 14 in a well known manner.", "The interface circuit(s) 20 are implemented using any type of well known interface standard, such as an Ethernet interface and/or a Universal Serial Bus (USB) interface.", "In the illustrated example, one or more input devices 22 are connected to the interface circuits 20 for entering data and commands into the main processing unit 12 .", "For example, an input device 22 may be a keyboard, mouse, touch screen, track pad, track ball, isopoint, and/or a voice recognition system.", "In the illustrated example, one or more displays, printers, speakers, and/or other output devices 24 are also connected to the main processing unit 12 via one or more of the interface circuits 20 .", "The display 24 may be a cathode ray tube (CRT), a liquid crystal display (LCD), or any other type of display, such as a hand-held display 500 as shown in FIG. 17 .", "The display 24 may generate visual indications of data generated during operation of the main processing unit 12 .", "For example, the visual indications may include prompts for human operator input, calculated values, detected data, etc.", "The illustrated computer system 10 also includes one or more storage devices 26 .", "For example, the computer system 10 may include one or more hard drives, a compact disk (CD) drive, a digital versatile disk drive (DVD), and/or other computer media input/output (I/O) devices.", "The illustrated computer system 10 may also exchange data with other devices via a connection to a network 118 .", "The network connection may be any type of network connection, such as an Ethernet connection, digital subscriber line (DSL), telephone line, coaxial cable, etc.", "The network 118 may be any type of network, such as the Internet, a telephone network, a cable network, and/or a wireless network.", "An example system for prosthesis fitting and balancing in joints is illustrated in FIG. 2 .", "In one embodiment, the system includes a prosthesis 30 , a joint angle sensor 36 , a ligament tension sensor 38 , an analysis program 40 , the main unit 12 , the one or more storage devices 26 , and the display 24 .", "As will be described in detail below, the artificial joint may comprise a femoral component 32 , a tibial tray 58 , and a spacer 34 with one or more imbedded sensors 35 .", "Any or all of the sensors 35 , 36 , 38 may be implemented by conventional sensor technology, including commercially available pressure sensors, tension sensors, and angle sensors.", "Furthermore, any or all of the storage device 26 , and the analysis program 40 may be implemented by conventional electronic circuitry, firmware, and/or by a microprocessor executing software instructions in a well known manner.", "However, in the illustrated example, the analysis program 40 is implemented by software stored on the memory 18 and executed by the processor 14 , while the storage device 26 may be implemented by database server software stored on the memory 18 , and executed by the processor 14 to physically store data on a hard drive.", "In addition, a person of ordinary skill in the art will readily appreciate that certain modules in the apparatus shown in FIG. 2 may be combined or divided according to customary design constraints.", "Still further, one or more of the modules may be located external to the main processing unit 12 .", "Turning to FIG. 3 , there is shown an example of the prosthesis 30 as used in conjunction with the replacement of a human knee 50 .", "In general, the human knee 50 comprises a femur 52 , a patella 53 , a tibia 54 , a plurality of ligaments (not shown), and a plurality of muscles (not shown).", "The prosthesis 30 generally comprises two parts, the femoral component 32 and a tibial component 56 .", "Additionally, the tibial component 56 is typically made up of two parts, the metal tibial tray 58 that is attached directly to the tibia 54 and the spacer 34 that provides the bearing surface.", "It will be understood that the while in the disclosed embodiment the tibial component 56 is comprised of separate components, the spacer 34 and the metal tibial tray 58 may be integrally formed.", "The materials used in a joint replacement surgery are designed to enable the joint to mimic the behavior or a normal knee joint.", "In the illustrated embodiment, the femoral component 32 is a metal piece, shaped similar to the end of the femur and fitting closely into a corresponding plastic spacer 34 .", "Several metals are typically used, including stainless steel, alloys of cobalt and chrome, and titanium, while the plastic material is typically constructed of a durable and wear resistant polyethylene.", "Other suitable materials may now exist or may be developed in the future.", "Plastic bone cement may be used to anchor the prosthesis 30 into the bones 52 , 54 , however, the prosthesis 30 may be implanted without cement when the prosthesis 30 and the bones 52 , 54 are designed to fit and lock together directly.", "A cemented prosthesis 30 is held in place by a type of epoxy cement that attaches the metal to the bones 52 , 54 .", "An uncemented prosthesis 30 has a fine mesh of holes on the surface that allows the bones 52 , 54 to grow into the mesh and attach the prosthesis 30 to the bones 52 , 54 .", "Referring now to FIGS. 4 and 5 , there is illustrated an example spacer 34 which may be used in conjunction with an embodiment of the system of FIG. 2 .", "The spacer 34 includes a pair of opposed faces 60 , 62 and an elongated side edge 64 .", "The face 60 comprises a pair of condyle recesses 68 , 66 , shaped to closely match or otherwise accommodate the shaped end of the femoral component 32 .", "The face 60 may also comprise an extension 70 which may slidably engage a groove 71 in the femoral component 32 and prevent lateral movement between the spacer 34 and the femoral component 32 , while allowing the two pieces to rotate relative to each other in a predefined range of motion similar to a biological knee, for example, between zero degrees (0°), i.e., extension, and ninety degrees (90°), i.e., flexion.", "The contact between the femoral component 32 and the spacer 34 will produce deformations in the two surfaces in contact, which may be measured by the sensors 35 embedded in the spacer 34 .", "The sensed deformation may cause an output to be created by the sensors 35 .", "The opposite face 62 includes an elevated face 72 .", "The elevated face 72 and the face 62 cooperate to form a snap-fit connection with the tibial tray 58 as is well known in the art.", "It will be noted that connection between the tibial tray 58 and the spacer 34 may vary according to known design variations.", "For instance, the elevated face 72 and the face 62 may be substantially coplanar and may be cemented onto the tibial tray 58 .", "In the illustrated embodiment of FIG. 5 , the elevated face 72 is illustrated with a plurality of recesses 74 .", "The recesses 74 are milled in the face 72 of the polyethylene and have a cross section sized to accept sensors 35 , thereby enabling the sensors 35 embedded in the spacer 34 .", "Since the sensors 35 are responsive to the deformation of the spacer 34 , the depth of the recesses 74 may be chosen to minimize the impact on the deformation characteristics of the spacer 34 , as well as to ensure an accurate reading based on the sensitivity of the sensor 35 .", "For example, in the illustrated embodiment, the recesses 74 have a cross section of appropriately dimensioned to accept a strain sensor marketed by Omega Engineering, Inc., of Stanford, Conn.", "In one embodiment, the recesses are arranged in an array and include a bar-shaped micro miniature strain gage (sensor 35 ) of approximate dimension 1 mm×0.5 mm×0.15 mm.", "The strain gage is responsive to the deformation of curvature with a maximum strain of 3000μ.", "Furthermore, the strain gage may provide data in a real-time, or near real-time fashion, allowing for intraoperative analysis of the data.", "A person of ordinary skill in the art will readily appreciate that other sensors may be used to sense the deformation of the spacer 34 .", "For example, a single sensor, or an array of sensors may be used to sense the deformation of the spacer 34 .", "Once the sensor 35 is placed in the recesses 74 , the recesses may be filled with a plug of the same, or similar, material as the spacer 34 , to further minimize the impact on the deformation characteristics of the spacer 34 .", "The recess plug may be, for example, glued in place, or held by an interference fit.", "Of course, a person of ordinary skill in the art will readily appreciate that any number of recesses 74 and sensors 35 may be utilized.", "Moreover, the dimensions of the recesses may vary greatly, depending upon the characteristics of the spacer 34 , the sensor 35 , and/or the desired sensitivity.", "Still further, it will be appreciated that the sensors 35 may be embedded within the spacer 34 utilizing any known or yet to be developed manufacturing method, including direct insertion during the molding process, as well as insertion utilizing a transverse cut in the spacer 34 .", "The spacer 34 illustrated in FIG. 5 includes a plurality of sensors 35 electrically coupled by a system interconnect (not shown) to one or more transceiver device(s) 76 .", "In the example, the system interconnect is a plurality of wires (not shown) transversely carried through the spacer 34 to the transceiver device(s) 76 .", "Of course, a person of ordinary skill in the art will readily appreciate that interconnects other than wires may be used to connect the sensors 35 to the transceiver devices(s) 76 .", "For example, one or more wireless connections may be used to connect the sensors 35 to the transceiver device(s) 76 .", "In the illustrated embodiment, the transceiver device(s) 76 is embedded within another recess 77 within the elevated face 72 of the spacer 34 , however, it will be understood that the transceiver may be located in any location, including external to the spacer 34 .", "In one embodiment, the transceiver device(s) 76 is a self powered, 5 channel input transceiver having approximate dimensions of 1.46 cm×3.05 cm×0.65 cm.", "The transceiver has a sample rate of 150 samples per second and is powered by a 3.1 volt minimum, 7 volt maximum, 13.8 DC battery.", "Additionally, the transceiver may contain a memory for storing sensor data.", "In operation, the transceiver device 76 is adapted to receive, as an input, multiple sensor outputs created by each of the sensors 35 in response to the deformation of the spacer 34 .", "The transceiver device 76 is further adapted to convert the multiple sensor inputs to a serial data stream and transmit the data stream, via wired or wireless connection, to the main unit 12 .", "The transceiver devices 76 is preferably a single battery powered transceiver capable of wireless transmission, however, it may be any type of transceiver known or yet to be developed, such as a magnetically powered transceiver.", "Furthermore, it will be appreciated by one of ordinary skill in the art that the transceiver device(s) 76 and the sensors 35 may be combined or divided according to customary design constraints.", "Still further, the spacer 34 with embedded sensors 35 may be designed to be substantially permanently attached to the tibial tray 58 , i.e., bioengineered to remain in the prosthesis 30 after surgery, or it may be temporarily attached to the tibial tray 58 , i.e., to be used only during the actual replacement surgery to gather data and replaced by a substantially permanent spacer.", "In the disclosed example, this is aided by the fact that the sensors 35 , etc.", "are fully encapsulated in the spacer 34 .", "Referring now to FIGS. 6 and 7 , there is illustrated a human knee exposed for surgery with the prosthesis 30 and sensors 35 , 36 , 38 in place.", "Specifically, the femoral component 32 is attached to the femur 52 , and the tibial component 56 is attached to the tibia 54 .", "The spacer 34 and embedded sensors 35 are in place between the femoral component 32 and the tibial tray 58 .", "In the illustrated embodiment, a plurality of ligament tension sensors 38 are attached to external knee ligaments, such as, for example, the medial cruciate ligament and the lateral cruciate ligament.", "Additionally, the joint angle sensor 36 may be attached to the surface of the human knee 50 .", "The ligament tension sensors 38 may be any commercially available tension sensors such as one marketed by Omega Engineering, Inc., of Stanford, Conn.", "The ligament tension sensor 38 is responsive to the tension of the ligament to which it is attached, and is adapted to produce an output in response to the sensed tension.", "The ligament tension sensor 38 may also comprise a transceiver (not shown) similar to the above-described transceiver device 76 .", "The data output from the ligament tension sensor 38 may thereby be transmitted to the main unit 12 .", "The joint angle sensor 36 may be any commercially available angle sensor such as—one marketed by Omega Engineering, Inc., of Stanford, Conn.", "The joint angle sensor 36 is responsive to the range of motion of the prosthesis 30 , and is adapted to produce an output representative of the joint angle.", "The joint angle sensor 36 may also comprise a transceiver (not shown) similar to the above-described transceiver device 76 .", "The data output from the joint angle sensor 36 may thereby be transmitted to the main unit 12 .", "As will be appreciate by one of ordinary skill in the art, the sensors 35 , 36 , 38 may be used in any number of combinations, depending upon the desired data collection strategy.", "For example, a practitioner may only be interested in the pressure between the spacer 34 and the femoral component 32 when the prosthesis is fully extended, and may therefore, only utilize the sensor 35 and the joint angle sensor 36 .", "Once all the desired sensors 35 , 36 , 38 are in place, it may be desirable to partially close the incision to evaluate the prosthesis 30 range of motion during flexion and extension.", "The surgeon may then flex the prosthesis 30 through its normal range of motion.", "The outputs from the sensors 35 , 36 , 38 are transmitted to the main unit 12 , wherein they may be captured by the analysis program 40 .", "In one embodiment, the analysis program 40 may be, for example, LabVIEW™ data acquisition software marketed by National Instruments Corp.", ", of Austin, Tex.", "and commercially available.", "The analysis program 40 may display the data in a variety of formats on the display(s) 24 , as will be described below.", "The analysis program 40 may be adapted to transmit the acquired data to the database server software stored on the memory 18 , and executed by the processor 14 to physically store data on a hard drive.", "In one embodiment, as shown by FIGS. 8 through 10A , the sensor 35 , 38 measurements are captured by the analysis program 40 and displayed as a pressure distribution graph.", "Specifically, referring to FIGS. 8 and 8A , the analysis program 40 displays a three dimensional pressure distribution graph 100 , in pounds per square in (lb/in 2 ) when the prosthesis 30 is in the zero degree (0°) extension position (illustrated by FIG. 8 ).", "As described in detail above, the pressure distribution graph is representative of the sensed pressure on the spacer 34 by the femoral component 32 .", "The illustrative pressure distribution graph 100 displays six regions of pressure sensor readings, namely an anterior 102 , 104 , a middle 106 , 108 , and a posterior region 110 , 112 , duplicated on both the medial and lateral portions of the spacer 32 respectively.", "It will be understood that while six regions 102 , 104 , 106 , 108 , 110 , 112 are displayed, each region may be comprised of any number of individual sensor readings, including multiple readings per region.", "Referring to FIGS. 9 and 9A , and FIGS. 10 and 10A , the analysis program 40 displays a three dimensional pressure distribution graph 120 , 140 in pounds per square in (lb/in 2 ) when the prosthesis 30 is in the thirty degree (30°) extension position (illustrated by FIG. 9 ), and when the prosthesis 30 is in the sixty degree (60°) extension position (illustrated by FIG. 10 ).", "As described in above, the illustrative pressure distribution graphs 120 , 140 display six regions of pressure sensor readings, namely an anterior 102 , 104 , a middle 106 , 108 , and a posterior region 110 , 112 , duplicated on both the medial and lateral portions of the spacer 32 respectively.", "The graphical pressure distribution graphs may allow the physician to adjust their surgical or medical procedures by examining the pressure within the prosthesis 30 at certain angles.", "For example, the physician may recognize, either by experience or knowledge of design constraints, that the medial anterior pressure region 102 of FIG. 8A is slightly elevated and may adjust the prosthesis 30 accordingly.", "Additionally, the analysis program 40 may provide the physician with the tension readings provided by the ligament tension sensors 38 (not shown) to aid the physician in determining whether, based upon the knowledge and skill of the surgeon, the ligaments should be adjusted.", "In yet another embodiment, the analysis program 40 may be adapted to compare the acquired data to the data stored by the database server software on the hard drive.", "For example, upon the collection of a number of trials of empirical data, the stored data may be statistically analyzed (either by the analysis program 40 , or another external program) to form suggested pre-determined pressure criteria, i.e., upper and lower limits, to aid the physician in recognizing potential elevated pressure readings.", "The suggested pre-determined pressure criteria may define statistically sound thresholds and allowable limits under certain conditions, and may be constantly adjusted as more information becomes available in the database.", "In yet another embodiment, as shown by FIGS. 11 and 12 , the sensor 35 , 38 measurements are captured by the analysis program 40 and displayed as a pressure graph as a function of joint angle.", "Specifically, referring to FIGS. 11 and 12 , the analysis program 40 displays a two dimensional pressure graph 200 , 220 in pounds per square inch (lb/in 2 ) when the prosthesis 30 is moving in the flexion range of motion ( FIG. 11 ) and when the prosthesis 30 is moving in the extension range of motion ( FIG. 12 ).", "Again, as described in detail above, the pressure distribution graph is representative of the sensed pressure on the spacer 34 by the femoral component 32 .", "FIG. 11 illustrates a graph plotting the six sensor regions 102 104 , 106 , 108 , 110 , 112 marked by their respective reference numerals versus joint angle, wherein the prosthesis 30 is moving in flexion.", "FIG. 12 illustrates a graph plotting the six sensor regions 102 104 , 106 , 108 , 110 , 112 marked by their respective reference numerals versus joint angle, wherein the prosthesis 30 is moving in extension.", "As the graphs of FIGS. 11 and 12 show, the pressure on each region varies according to joint angle, providing the physician with a graphical understanding of the mechanics of the prosthesis 30 and allowing the physician to adjust their surgical or medical procedures by examining the pressure within the prosthesis 30 over the full range of motion.", "It will be understood that the sensor 35 , 36 , 38 measurements captured by the analysis program 40 and may be displayed in any number of various ways, including, raw data dumps, and as graphs, similar to those disclosed above.", "For example, in another embodiment (not shown), the analysis program 40 may display a pressure graph as a function of ligament tension.", "It will be appreciated, however, that the example graphs above are merely illustrative, and are no way limiting.", "In still another embodiment, the outputs from the sensors 35 , 36 , 38 may be transmitted to the main unit 12 , wherein they may be captured by another embodiment of the analysis program 40 which may be, for example, a finite element analysis program (“FEA”", "program).", "An example of an FEA program is the ANSYS Finite Element Analysis software program marketed by ANSYS Inc. located in Canonsburg, Pa.", ", and commercially available.", "The FEA analysis program 40 is flexible, and may display the data in a variety of formats on the display(s) 24 .", "In one embodiment, as shown by FIGS. 13 through 15 , the sensor 35 , 38 measurements are captured by the FEA analysis program 40 and displayed as both a pressure distribution graph, and as a pressure topography graph.", "Specifically, referring to FIG. 13 , the FEA analysis program 40 displays a three dimensional pressure topography graph 300 , in kilopascal (kPa) when the prosthesis 30 is in the zero degree (0°) position.", "Similar to the other embodiments, for example a pressure distribution graph 310 , and as described in detail above, the pressure topography graph 300 is representative of the sensed pressure on the spacer 34 by the femoral component 32 at a specific angle.", "Unlike the pressure distribution graph 310 , however, the illustrative pressure topography graph 300 displays the pressure in relationship to the modeled spacer 34 , allowing the practitioner to identify the location of the pressure points in spatial relation to the spacer 34 used.", "Referring to FIGS. 14 and 15 , the analysis program 40 displays a three dimensional pressure topography graph 320 , 340 in kilopascal (kPa) when the prosthesis 30 is in the forty degree (40°) position (illustrated by FIG. 14 ), and when the prosthesis 30 is in the ninety degree (90°) position (illustrated by FIG. 15 ).", "As described in above, the illustrative pressure topography graphs 320 , 340 displays pressure in relationship to the modeled spacer 34 , as opposed to the six region pressure distribution graphs 330 , 350 .", "Referring now to FIG. 16 , there is illustrated a jig 400 which may be used in the operative environment of FIGS. 6 and 7 , or alternatively, in a testing environment, such as cadaver testing, or the like.", "The jig 400 is arranged to control the flexion of the prosthesis 30 in the intra operative environment is such a way that a number of variables may be controlled.", "For example, the jig may control, for instance, the rate of flexion and extension, the total range of motion, and the axis of motion, etc.", ", in such a manner that the user may experience consistent and reproducible results when testing various aspects of the prosthesis 30 .", "It will be noted that while the above description relates to an embodiment of a human a prosthetic, it will be readily understood that the principles of the present invention may be applied to any type of replacement joint, as well as any living organism.", "For example, the sensors 35 of the present embodiment may be utilized to replace a hip joint, or other joint, including the ankle, foot, shoulder, elbow and fingers.", "For instance, in hip joint replacement, the damaged ball (the upper end of the femur) is replaced by a metal ball attached to a metal stem fitted into the femur, and a plastic socket is implanted into the pelvis, replacing the damaged socket.", "The sensors 35 may be embedded within the plastic socket (or other location) to provide the practitioner with data related to the contact between the metal stem and the socket.", "It will be further understood that the main unit 12 may be arranged to receive input from an MRI, CAT scan, X-ray, and/or other diagnostic device to feed the analysis program 40 with that input.", "The analysis program 40 may then convert that input to a model of the patient's knee.", "The model may reduce or eliminate the need for conventional intermedullar rods conventionally used to determine the specific of the tibial and femoral cut down, such as location, angle, etc.", "One example of these data collection, finite element analysis and/or joint modeling steps, along with there respective graphical outputs or displays is shown in FIG. 18 .", "A system and method according to the disclosed example may serve to improve longevity and function of Total Knee Arthroplasty (TKA).", "The accurate balancing of the forces acting on the joint in a total knee arthroplasty results in proper component placement and proper tensioning of the ligamentous structures that cross the knee joint.", "When a knee arthroplasty is properly balanced, stresses are evenly distributed in the articulating components through a full range of motion.", "Functionally poor ligament balance, which can create instability causing acute subluxation or dislocation of the total knee components, may be reduced or eliminated.", "On the other hand, tight ligaments can produce stiffness limiting or precluding knee motion.", "More subtle discrepancies in ligament balancing create abnormally high peak stresses in the articular components and at the bone prosthesis interface causing catastrophic failure of polyethylene tibial components or mechanical loosening at the bone cement interface.", "Additionally, undue stresses can increase component wear, which is deleterious because the wear particles are phagocytized by macrophages initiating an inflammatory cascade that stimulates osteoclast activity.", "This causes osteolysis with bone loss and degradation of the bone implant interface and eventual loosening.", "In accordance with the disclosed example, the necessary experimental and analytical tools to quantify and standardize balancing of the knee joint during TKA may be developed.", "Additional data may be collected from cadaver total knee arthroplasty experiments in order to correlate stress measurements with abnormalities of ligamentous balance and component position.", "Using the system disclosed herein, as the knee is flexed through a complete range of motion the pressures may be collected in real time or in near real time.", "While the knee is flexed tension will be measured in the structures bridging the joint to measure the effect of increased tension on the stress values.", "Data may also be obtained on the effect of component malposition on the stresses across the knee.", "The data obtained may be used to create a mathematical model for knee arthroplasty.", "For example, a clinical advisory board of orthopedic surgeons may be established to define possible criteria needed to achieve acceptable conformity in a balanced knee.", "A rough paradigm may be developed to aid in guiding the surgeon in interpretation of stress data obtained during knee arthroplasty.", "Stress data may be obtained during total knee implantation intraoperatively using a wireless sensory device.", "The paradigm may be tested and fine tuned so that stress data can guide the surgeon in achieving proper balance when performing TKA.", "The disclosed system may further aid in investigating the force requirements from the collateral segments and how they influence the pressure/contact between the femoral and tibial component during flexion-extension.", "The effects of pressure on the wear on the polyethylene component of the biomechanics of the knee may be readily studied, threshold limits of pressure values deemed acceptable to balance the knee after TKA may be developed.", "An analytical dynamical model of the knee will used to analyze the experimental data.", "A dynamic model of the knee depicting all the intricate details such as contact in the presence of active forces, patella, collateral ligaments, attachment points, bone density, design characteristic of the prosthesis, interface between bone and femoral-tibial components, may be developed using known methodologies.", "In this phase of the study pressure profiles will be created corresponding to specific increments of misalignment.", "This synthesis will validate the information with the concurrent experiment that has implemented the sensor technology.", "An advisory board will be set up where clinicians and surgeons will set up threshold for contact pressure in the TKA.", "Based on precalibrated values of experimental study, the surgeon can then do proper ligament release or component exchange to bring the values within acceptable limits.", "Eventually, this will be taken as guidelines which will allow a precision fit in the operating room without any reliance on the experience of the surgeon.", "Effectively this study will lead in achieving a higher level of joint mobility performance in arthritic patient.", "Ultimately, not only a better tracking mechanism of wear and performance of the TKA will be developed but also the clinician's performance during the surgery will be evaluated through the quantitative feedback he receives.", "Based on the results a special jig 400 will be designed to immobilize the femur while allow free motion of the tibia and quadriceps mechanism.", "The components will then be implanted and the knee will be placed in the special jig 400 .", "A computerized winch will pull on the quadriceps tendon duplicating the force and the direction of the quadriceps muscle.", "The rectus femoris and vastus intermedius will be tied together and loaded with a 30-N weight, the rectus medialis will be loaded with 25-N weight and the vastus lateralis will be loaded with 20-N.", "Finally, a high precision potentiometer (shape sensor) will be used to measure the joint angle.", "The knee will then be flexed and extended from 0 to 9° degrees.", "A distribution of contact pressure will be recorded as a function of angle.", "The leg will also be outfitted with an angle sensor on the side of the knee in order to measure joint angle.", "The sensors will allow readings of stress and tension in real time as the knee is brought through the complete flexion cycle.", "The effect of each particular reefing on peak joint stresses will be measured and abnormal tension in the shortened ligament will be correlated with peak joint stresses through the flexion cycle.", "Finally the components will be placed in abnormal positions of valgus, varus, flexion and extension and the pressures again measured through the flexion cycle.", "A Sample Experimental Procedure: An experimental knee replacement procedure was performed on a mock human knee 50 .", "Once the experimental knee replacement surgery was performed, a traditional spacer was removed and replaced with one that had six pressure sensors 35 .", "the sensors 35 and the main unit 12 were coupled through the use of wires.", "The knee 50 was stitched with the wires running through the wound.", "The femur 52 was immobilized with the jig 400 and the quadriceps were loaded.", "The joint angle sensors 36 were put in place.", "The knee 50 was then extended and flexed through the normal range of motion many times.", "The rate pf flexion was approximately 20 degrees per second.", "Caution was taken in order not to apply external varus or valgus stress.", "The cycle of extension and flexion was repeated many times and recordings were averaged.", "A finite element model was created by scanning the actual spacer 34 with a laser micrometer and importing the geometry into a computer file.", "Using Autocad, a three dimensional file was refined and then exported in to an ANSYS compatible format.", "The current ANSYS spacer model has over 23,000 elements, which have 20 nodes each and a tetrahedral shape.", "On the surface of each condyle 66 , 68 , twelve hundred and fifty nine (1259) nodes resided.", "These nodes are responsible for the application of all pressure and forces to the model while the bottom surface is constrained to have zero displacement.", "The spacer model was designed so that data could be inputted into the model easily using data from the output sensors 35 .", "ANSYS was then used to generate the necessary plots of stress—both principal stresses and von-Mises stress plots of the deformation of the tibia component were be displayed as function of time variant pressure do to tibiofemoral contact.", "The contact pressures at each sensor 35 was displayed for knee extension and flexion.", "The joint angle range of motion varied from roughly ninety degree (90°) to zero degrees (0°).", "During knee extension, very small contact forces were recorded while the knee was between ninety degrees (90°) and fifty degrees (50°).", "For example, one sensor showed activity between fifty degrees (50°) and twenety five degrees (25°) with a maximum of 40 psi at approximately 35°.", "Another sensor recorded a maximum at sixteen degrees (16°) with pressure of 110 psi.", "During flexion, contact pressures were recorded with slightly larger magnitudes.", "For example one sensor, which recorded no more than 3-psi during extension, recorded 10-psi at around seventy five degrees (75°) during flexion.", "Similarly, another sensor which recorded a maximum at thirty five degrees (35°) during extension, recorded a maximum while at twenty five degrees (25°) during flexion.", "As a result, it may be concluded that for this experiment, forces on the medial and lateral condyle were not balanced in phase or magnitude.", "This would suggest a varus-valgus unstable knee.", "The high pressure recorded at the extended end of the graph suggested a joint that is too tight.", "Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the forgoing description.", "Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention.", "The details of the system may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which are within the scope of any subsequent claims is reserved." ]
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a U.S. National Stage Application of PCT/IB009/053763, filed Aug. 28, 2009, which designates the United States and claims the priority of Italian Patent Application No. TO2008A000646, filed on Aug. 29, 2008. BACKGROUND [0002] 1. Field of Invention [0003] The present invention refers to a concentrator and locator device of a solute and to a method for concentrating and locating a solute present in a solution. [0004] 2. Related Art [0005] Micro-structured surfaces are known having a geometry such as to reproduce the behaviour of lotus leaves, so as to exploit the known “Lotus Effect”. [0006] Lotus leaves display a particular behaviour when they are wet by a liquid; the liquid forms into distinct droplets due to the micrometric corrugation of such surfaces. Such a milimetric corrugation creates high contact angles at the water—leaf surface—air interface. Consequently, the liquid tends to slide off from the surface without dampening it due to a reduced adhesion at the surface itself. [0007] These surfaces are therefore typically used as self-cleaning surfaces since they have a hydrophobic behaviour. [0008] It is often required to identify a solute present inside the solution. This is typically carried out by using, for example, optical devices based on UV (Ultraviolet) absorption, dynamic light scattering, infrared spectroscopes or devices which exploit chemical properties such as liquid or gas phase chromatography. [0009] However, such devices have the drawback that, when the solution is very diluted, it is difficult to locate the solute, and it is thus necessary to perform an analysis on the entire solution, taking a long time before being able to identify the desired substance. SUMMARY [0010] The purpose of the present invention is therefore that of proposing a concentrator and locator device of a solute and a method for concentrating and locating a solute in a small region of space, so as to allow the solute itself to be rapidly identified. [0011] Briefly, the device according to an embodiment of the invention exploits the high contact angle which is formed between the surface of the device and the solute placed on it, and the super-hydrophobicity of such a surface, to detect, exploiting the principle of evaporation, molecules diluted in the solute up to attomolar (10 −18 mols/litre) concentrations. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Further characteristics and advantages of embodiments of the invention shall become clear in the following detailed description, carried out purely as non-limiting example, with reference to the attached drawings, in which: [0013] FIG. 1 is a top view of a device according to an embodiment of the invention, and [0014] FIG. 2 is a flow diagram of the operations according to the method of an embodiment of the invention. DETAILED DESCRIPTION [0015] In FIG. 1 a device according to an embodiment of the invention is wholly indicated with reference numeral 1 . Such a device 1 comprises a substrate 2 , for example silicon or a photopolymer or glass, on which there are prismatic lithographic microstructures 4 , preferably having the shape of a parallelepiped, with a shape ratio (the ratio between the height of the parallelepiped and the area of the base) which is greater than a predetermined value T, for example 20. Such microstructures 4 are arranged orthogonally at the surface of the substrate 2 , and they are periodically spaced from each other at a predetermined distance 6 , comprised in the range 20-50 μm, and they have a base area comprised in the range 1-10 μm. [0016] The microstructures 4 , made for example from silicon or from photopolymers, are obtained through per se known deposition or lithography and attack processes. [0017] The substrate 2 becomes super-hydrophobic thanks to the presence of such periodic micro-structures 4 . [0018] In a first variant of the invention, on the top 8 of the microstructures 4 an electroless deposition of noble metals is carried out, like for example silver or gold. An oxidation-reduction reaction of the noble metals is obtained which creates a continuous corrugated film of silver or gold on the top 8 of the microstructures 4 . [0019] In a second and third variant of the invention, nano-structures are formed on the top 8 of each lithographic micro-structure 4 . [0020] In particular, in the second variant of the invention a combination of high resolution electron beam lithography and electroless deposition of noble metals such as silver or gold is made. A reaction of oxidation-reduction of the noble metals is made which creates on the top 8 of the microstructures 4 a matrix shaped sub-frame making a checkerboard of nano-cylinders having a height comprised in the range 30-100 nm and a periodicity comprised in the range 35-125 nm. Such nano-cylinders have a diameter comprised in the range 30-100 nm and are arranged orthogonally with respect to the surface of the top 8 . [0021] In the third variant of the invention, instead of the nano-cylinders a plasmonic lens is made, or rather a linear chain (self-similar) comprising a plurality of nano-spheres, in particular three, having a diameter comprised in the range 10-100 nm. [0022] Thereafter, some mono-layers of a predetermined material, preferably polytetrafluoroethylene (PTFE—also known as Teflon®, a registered trademark of DuPont), having an overall thickness comprised in the range 1-2 nm are deposed on the microstructures 4 . [0023] At this point, after having made the device 1 , it is possible to use said device 1 to concentrate and locate a quantity of solute dissolved inside a solution. [0024] FIG. 2 illustrates a flow diagram of the operations to perform according to an embodiment of the invention. [0025] The first operation 50 is to depose a drop of solution, preferably an inorganic solution or a protein suspension, at room temperature, on a device 1 of the type illustrated above, said drop having a spherical shape with a diameter comprised in the range 100 μm-3 mm. Such a drop positions itself on a group of microstructures 4 , for example on an area defined by 50×50 microstructures 4 , and remains still, suspended on the microstructures 4 , thanks to the high contact angle existing between the drop and the microstructures 4 themselves. Preferably, such a contact angle is comprised in the range 160°-170°. Thanks to the presence of mono-layers of Teflon, the contact angle at the solution—micro-structures—air interface is thus increased with respect to the value which it would have without such monolayers. [0026] In step 55 a predetermined length of time should be waited, for example 20 minutes; in such a length of time the solvent of the drop evaporates and the drop reduces in size maintaining its spherical shape. After the solvent has evaporated the drop reduces in size without however leaving solute residue on the microstructures 4 , which it abandons due to its size reduction. [0027] Moreover, the drop remains suspended on the microstructures 4 without penetrating between them, thanks to the high contact angle. [0028] In step 60 the evaporation step is repeated thus progressively reducing the size of the drop, up until, for example, the drop has a diameter equal to 40 μm, maintaining the quantity of solute initially present in the drop unaltered but increasing its concentration by up to ten thousand times. [0029] Such a drop with reduced diameter is deposed on a lower number of lithographic micro-structures 4 , for example on four or eight microstructures 4 , on an area 10 equal, for example, to 20 μm 2 . [0030] When the drop reaches a predetermined minimum radius, for example equal to 40 μm, it collapses (step 65 ), or rather it spreads evenly upon the lithographic microstructures 4 of the area 10 . [0031] Thanks to this progressive reduction process of the size of the drop without losing solute, a solute concentration is obtained with respect to the initial drop, in particular a concentration equal to ten thousand times more. Moreover, the solute is located in a predetermined and very small area 10 of the device. [0032] In step 70 the solute is detected, by scanning, for example, the area 10 with a [0033] Raman or fluorescent microscope. The area 10 is illuminated with a microscope which sends a beam of laser light having a predetermined electric field towards said area 10 and the light reflected by the area 10 of the device 1 is analysed through diffraction gratings obtaining a reflection spectrum. By performing a spectroscopic analysis of the reflection spectrum the solute present in the drop is detected. [0034] The corrugated film of gold or silver or the nano-structures made on the top 8 of the lithographic microstructures 4 in the area 10 amplify the local electric field, which then becomes greater than the electric field of the incident light, forming surface plasmons. In this way a very high detection sensitivity is reached, in particular even a single molecule of solute can be detected. [0035] Alternatively, such a solute is a polluting chemical agent, for example a dioxin, and the device 1 according to an embodiment the invention is made on a packaging film. It is therefore possible to exploit the device 1 to detect, performing the aforementioned concentration and locating procedure operations, the presence of polluting substances on the packaging of food products, clothing items, etc. [0036] Clearly, the principle of the invention remaining the same, the embodiments and the constructive details can be widely varied with respect to what has been described and illustrated purely as an example and not for limiting purposes, without for this reason departing from the scope of protection of the present invention defined by the attached claims.
Concentrator and locator device ( 1 ) of a solute comprising a substrate ( 2 ) and a plurality of prismatic lithographic micro-structures ( 4 ) orthogonally emerging from the substrate ( 2 ). The microstructures ( 4 ) are spaced from one another in a periodical manner so as to make such a substrate ( 2 ) super-hydrophobic.
Concisely explain the essential features and purpose of the concept presented in the passage.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a U.S. National Stage Application of PCT/IB009/053763, filed Aug. 28, 2009, which designates the United States and claims the priority of Italian Patent Application No. TO2008A000646, filed on Aug. 29, 2008.", "BACKGROUND [0002] 1.", "Field of Invention [0003] The present invention refers to a concentrator and locator device of a solute and to a method for concentrating and locating a solute present in a solution.", "[0004] 2.", "Related Art [0005] Micro-structured surfaces are known having a geometry such as to reproduce the behaviour of lotus leaves, so as to exploit the known “Lotus Effect.”", "[0006] Lotus leaves display a particular behaviour when they are wet by a liquid;", "the liquid forms into distinct droplets due to the micrometric corrugation of such surfaces.", "Such a milimetric corrugation creates high contact angles at the water—leaf surface—air interface.", "Consequently, the liquid tends to slide off from the surface without dampening it due to a reduced adhesion at the surface itself.", "[0007] These surfaces are therefore typically used as self-cleaning surfaces since they have a hydrophobic behaviour.", "[0008] It is often required to identify a solute present inside the solution.", "This is typically carried out by using, for example, optical devices based on UV (Ultraviolet) absorption, dynamic light scattering, infrared spectroscopes or devices which exploit chemical properties such as liquid or gas phase chromatography.", "[0009] However, such devices have the drawback that, when the solution is very diluted, it is difficult to locate the solute, and it is thus necessary to perform an analysis on the entire solution, taking a long time before being able to identify the desired substance.", "SUMMARY [0010] The purpose of the present invention is therefore that of proposing a concentrator and locator device of a solute and a method for concentrating and locating a solute in a small region of space, so as to allow the solute itself to be rapidly identified.", "[0011] Briefly, the device according to an embodiment of the invention exploits the high contact angle which is formed between the surface of the device and the solute placed on it, and the super-hydrophobicity of such a surface, to detect, exploiting the principle of evaporation, molecules diluted in the solute up to attomolar (10 −18 mols/litre) concentrations.", "BRIEF DESCRIPTION OF THE DRAWINGS [0012] Further characteristics and advantages of embodiments of the invention shall become clear in the following detailed description, carried out purely as non-limiting example, with reference to the attached drawings, in which: [0013] FIG. 1 is a top view of a device according to an embodiment of the invention, and [0014] FIG. 2 is a flow diagram of the operations according to the method of an embodiment of the invention.", "DETAILED DESCRIPTION [0015] In FIG. 1 a device according to an embodiment of the invention is wholly indicated with reference numeral 1 .", "Such a device 1 comprises a substrate 2 , for example silicon or a photopolymer or glass, on which there are prismatic lithographic microstructures 4 , preferably having the shape of a parallelepiped, with a shape ratio (the ratio between the height of the parallelepiped and the area of the base) which is greater than a predetermined value T, for example 20.", "Such microstructures 4 are arranged orthogonally at the surface of the substrate 2 , and they are periodically spaced from each other at a predetermined distance 6 , comprised in the range 20-50 μm, and they have a base area comprised in the range 1-10 μm.", "[0016] The microstructures 4 , made for example from silicon or from photopolymers, are obtained through per se known deposition or lithography and attack processes.", "[0017] The substrate 2 becomes super-hydrophobic thanks to the presence of such periodic micro-structures 4 .", "[0018] In a first variant of the invention, on the top 8 of the microstructures 4 an electroless deposition of noble metals is carried out, like for example silver or gold.", "An oxidation-reduction reaction of the noble metals is obtained which creates a continuous corrugated film of silver or gold on the top 8 of the microstructures 4 .", "[0019] In a second and third variant of the invention, nano-structures are formed on the top 8 of each lithographic micro-structure 4 .", "[0020] In particular, in the second variant of the invention a combination of high resolution electron beam lithography and electroless deposition of noble metals such as silver or gold is made.", "A reaction of oxidation-reduction of the noble metals is made which creates on the top 8 of the microstructures 4 a matrix shaped sub-frame making a checkerboard of nano-cylinders having a height comprised in the range 30-100 nm and a periodicity comprised in the range 35-125 nm.", "Such nano-cylinders have a diameter comprised in the range 30-100 nm and are arranged orthogonally with respect to the surface of the top 8 .", "[0021] In the third variant of the invention, instead of the nano-cylinders a plasmonic lens is made, or rather a linear chain (self-similar) comprising a plurality of nano-spheres, in particular three, having a diameter comprised in the range 10-100 nm.", "[0022] Thereafter, some mono-layers of a predetermined material, preferably polytetrafluoroethylene (PTFE—also known as Teflon®, a registered trademark of DuPont), having an overall thickness comprised in the range 1-2 nm are deposed on the microstructures 4 .", "[0023] At this point, after having made the device 1 , it is possible to use said device 1 to concentrate and locate a quantity of solute dissolved inside a solution.", "[0024] FIG. 2 illustrates a flow diagram of the operations to perform according to an embodiment of the invention.", "[0025] The first operation 50 is to depose a drop of solution, preferably an inorganic solution or a protein suspension, at room temperature, on a device 1 of the type illustrated above, said drop having a spherical shape with a diameter comprised in the range 100 μm-3 mm.", "Such a drop positions itself on a group of microstructures 4 , for example on an area defined by 50×50 microstructures 4 , and remains still, suspended on the microstructures 4 , thanks to the high contact angle existing between the drop and the microstructures 4 themselves.", "Preferably, such a contact angle is comprised in the range 160°-170°.", "Thanks to the presence of mono-layers of Teflon, the contact angle at the solution—micro-structures—air interface is thus increased with respect to the value which it would have without such monolayers.", "[0026] In step 55 a predetermined length of time should be waited, for example 20 minutes;", "in such a length of time the solvent of the drop evaporates and the drop reduces in size maintaining its spherical shape.", "After the solvent has evaporated the drop reduces in size without however leaving solute residue on the microstructures 4 , which it abandons due to its size reduction.", "[0027] Moreover, the drop remains suspended on the microstructures 4 without penetrating between them, thanks to the high contact angle.", "[0028] In step 60 the evaporation step is repeated thus progressively reducing the size of the drop, up until, for example, the drop has a diameter equal to 40 μm, maintaining the quantity of solute initially present in the drop unaltered but increasing its concentration by up to ten thousand times.", "[0029] Such a drop with reduced diameter is deposed on a lower number of lithographic micro-structures 4 , for example on four or eight microstructures 4 , on an area 10 equal, for example, to 20 μm 2 .", "[0030] When the drop reaches a predetermined minimum radius, for example equal to 40 μm, it collapses (step 65 ), or rather it spreads evenly upon the lithographic microstructures 4 of the area 10 .", "[0031] Thanks to this progressive reduction process of the size of the drop without losing solute, a solute concentration is obtained with respect to the initial drop, in particular a concentration equal to ten thousand times more.", "Moreover, the solute is located in a predetermined and very small area 10 of the device.", "[0032] In step 70 the solute is detected, by scanning, for example, the area 10 with a [0033] Raman or fluorescent microscope.", "The area 10 is illuminated with a microscope which sends a beam of laser light having a predetermined electric field towards said area 10 and the light reflected by the area 10 of the device 1 is analysed through diffraction gratings obtaining a reflection spectrum.", "By performing a spectroscopic analysis of the reflection spectrum the solute present in the drop is detected.", "[0034] The corrugated film of gold or silver or the nano-structures made on the top 8 of the lithographic microstructures 4 in the area 10 amplify the local electric field, which then becomes greater than the electric field of the incident light, forming surface plasmons.", "In this way a very high detection sensitivity is reached, in particular even a single molecule of solute can be detected.", "[0035] Alternatively, such a solute is a polluting chemical agent, for example a dioxin, and the device 1 according to an embodiment the invention is made on a packaging film.", "It is therefore possible to exploit the device 1 to detect, performing the aforementioned concentration and locating procedure operations, the presence of polluting substances on the packaging of food products, clothing items, etc.", "[0036] Clearly, the principle of the invention remaining the same, the embodiments and the constructive details can be widely varied with respect to what has been described and illustrated purely as an example and not for limiting purposes, without for this reason departing from the scope of protection of the present invention defined by the attached claims." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a display device, especially to an improved technology of gradation display. 2. Description of the Related Art TFT-ELDs, namely thin-film-transistor (TFT) driven electoroluminescent displays, which include electoroluminescent elements (EL elements) driven and controlled by thin film transistors, are considered as future potential displays due to their light weight, small size, high resolution, wide visual field, low electric consumption, etc. FIG. 4 is a circuit diagram of a conventional TFT-ELD, and FIG. 5 is a cross section of such TFT-ELD. FIG. 4 shows a unit pixel 11 of the TFT-ELD, a scanning line 12 , a signal line 13 , current supplying line 14 , a retention capacitor 15 , a selective transistor 16 , a driving transistor 17 , and an EL element 15 . As shown in FIG. 5, the driving transistor 17 for adjusting light emission intensity (gradation) of the EL element 18 is formed on a glass substrate 10 . A drain electrode of the driving transistor 17 is connected to a cathode (transparent electrode) 21 of the EL element 18 , and a source electrode is connected to the analog signal supply line 14 . The EL element 18 is formed of the anode 21 , a luminescent layer 22 , and an cathode 23 . The EL element 18 may be a inorganic electroluminescent element, a low-molecular organic electroluminescent element, or a high-molecular organic electroluminescent element. The selective transistor 16 includes a gate electrode connected to the scanning line 12 , a source electrode connected to a signal line 13 , and a drain electrode connected to a gate electrode of the driving transistor 17 . The retention capacitor 15 is provided between the analog signal supplying line 14 and the source electrode of the selective transistor 16 . In order to cause the EL element 18 to emit light in the aforementioned structure, the scanning line 12 and the signal line 13 are set at level “H”, and current is conducted between the drain and the source of the selective transistor 16 , whereby the driving transistor 17 is on state. An analog signal supplied from the analog supplying line 14 in this condition is delivered to the retention capacitor 15 and alters the conductance of the driving transistor 17 . As a result, the EL element 18 emits light with light emission intensity pursuant to the analog signal, thereby accomplishing gradations of light emission intensity. However, as a problem of the above-described. structure, resolution of the picture lowers due to the EL element 18 included in each pixel emitting light with unequal light emission intensity, especially in the middle gradation, because of the difference in the transistor properties of the driving transistor 17 . In order to solve this problem, the applicant of the present invention suggested in Japanese Patent Laid-Open Publication No. HEI 11-73158 a technology of displaying respective gradations by controlling on/off states of light emission of EL elements and changing the luminous area for each gradation. FIG. 6 is a circuit diagram of the TFT-ELD disclosed in said Laid-Open Publication. FIG. 6 shows an EL element included in each pixel, which is formed of EL elements 18 - 1 and 18 - 2 . Such structure allows display of four gradations by controlling on/off states of EL elements 18 - 1 and 18 - 2 respectively via a 2-bit signal line formed of signal lines 13 - 1 and 13 - 2 . More specifically, there are: gradation “0”, where neither EL element 18 - 1 nor 18 - 2 emits light; gradation “1”, where only EL element 18 - 1 emits light; gradation “2”, where only EL element 19 - 2 emits light; and gradation “3”, where both EL elements 18 - 1 and 18 - 2 emit light. Luminous areas of EL element 18 - 1 and EL element 18 - 2 are in a ratio of 1:2. As shown in FIG. 7, in the structure above, signals S, D 1 , and D 2 are respectively supplied to the scanning line 12 , signal line 13 - 1 and signal line 13 - 2 . When signal S is set at level “H”, current is conducted between the drain and the sources of selective transistors 16 - 1 and 16 - 2 . In FIG. 7, gradation “1” is obtained when signal S is set at level “H”, signal D 1 at level RHO, and signal D 2 at level “L”. As a consequence, driving transistor 17 - 1 is turned on, and transistor 17 - 2 is turned off, whereby only EL element 18 - 1 emits light. Furthermore, in order to realize gradation “2”, signal S should be set at level “H”, signal D 1 at level “L”, and signal D 2 at level “H”. By doing so, driving transistor 17 - 2 is turned on and transistor 17 - 1 is turned off, and consequently, only EL element 18 - 2 emits light. In this method, driving transistors 17 - 1 and 17 - 2 are to be regarded as either almost completely on state or almost completely off state. When driving transistors 17 - 1 and 17 - 2 are on state,resistance is negligibly small compared to the resistance of driving transistors 18 - 1 and 18 - 2 , such that the amount of current conducted through driving transistors 17 - 1 , 17 - 2 , 18 - 1 and 18 - 2 depends substantially on the resistance of driving transistors 18 - 1 and 18 - 2 alone. Accordingly, light emission intensity is never uneven due to the difference in the transistor properties of driving transistors 18 - 1 and 18 - 2 . Furthermore, when driving transistors 17 - 1 and 17 - 2 are off state, the voltage applied to EL elements 18 - 1 and 18 - 2 will be smaller than the threshold voltage, and driving transistors 18 - 1 and 19 - 2 , will not emit light at all. Therefore, also in this case, the light emission intensity of EL elements 18 - 1 and 18 - 2 is never uneven by the difference in the transistor properties of driving transistors 18 - 1 and 18 - 2 . However, as a disadvantage of the aforementioned structure, the luminous center (the average position of the luminescent portion) shifts for each gradation and visibility is thereby decreased. Characteristics of such disadvantage will be explained with reference to FIGS. 8A-D. FIG. 8C, for example, shows a luminous center 40 of the unit pixel element 11 . The EL element 18 - 1 shown with oblique lines means that no light is emitted, and the EL element 18 - 2 shown in white means that light is emitted. In FIG. 8A, the EL elements 18 - 1 , 18 - 2 do not emit light. In FIG. 8B, only EL element 18 - 1 emits light. In FIG. 8C, only EL element 18 - 2 emits light. Finally, in FIG. 8D, both EL elements 18 - 1 , 18 - 2 emit light. It is clear from these drawings that the position of the luminous center 40 changes for each gradation. As a consequence, when the brightness of a displayed image is changed, the position of the image shifts unfavorably. Furthermore, if the displayed image is actually observed here, the displayed image will be seen to flicker, causing an impression of unnatural display or fatigue to the viewer. SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to overcome such disadvantage and to provide a display device wherein a luminous center does not shift for each light emission gradation. In the present invention, in order to achieve said object, a unit pixel is formed of multiple EL elements whose luminescent portions corresponding to each gradation are arranged point-symmetrically with one another with respect to a prescribed point. Such structure allows provision of a display device wherein the position of a luminous center does not change for each gradation. “Prescribed position” here means, for example, a luminous center of the EL element upon realizing the gradation of minimum luminance. Furthermore, each electroluminescent element is preferably configured to have a state of “emission” or “non-emission”. By controlling on/off of the multiple Aluminescent elements, it is possible to prevent uneven aluminance caused by difference in the properties of luminescent elements. In order to achieve the structure above, electroluminescent elements may, for example, be used as luminescent elements, so that thin-film transistors may control the on/off states of light emission by the luminescent elements. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-D are explanatory diagrams showing the emission state of the respective EL elements forming a unit pixel in the TFT-ELD according to embodiment 1; FIGS. 2A-D are explanatory diagrams showing a unit pixel in the TFT-ELD according to embodiment 2; FIGS. 3A-D are explanatory diagrams showing the emission state of the respective EL elements forming a unit pixel in the TFT-ELD according to embodiment 2; FIG. 4 is a circuit diagram of a unit pixel in a conventional TFT-ELD. FIG. 5 is a cross section of a unit pixel in a conventional TFT-ELD. FIG. 6 is a circuit diagram of a unit pixel in a conventional TFT-ELD; FIG. 7 is a timing chart indication a scanning line and a signal line of a conventional TFT-ELD; and FIGS. 8A-D are explanatory diagrams showing the light emission state of the EL elements forming a unit pixel of a conventional TFT-ELD. DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1A-D show a unit pixel 11 included in a display device according to the present invention. Each unit pixel has EL elements 18 - 10 , 18 - 21 and 18 - 22 , and is a 2 bit-4 gradation display. In FIG. 1A, for example, EL element 18 - 10 is an EL element for 0-bit display. The on/off states of EL elements 18 - 21 and 18 - 22 are simultaneously controlled by the same driving transistor, and EL element 18 - 21 is a first EL element for 1-bit display and EL element 18 - 22 is a second EL element for 1-bit display. Each EL element is driven and controlled by two scanning lines (for 0-bit and 1-bit display) which are not shown. Furthermore, although FIGS. 1A-D show only the unit pixel element 11 , in reality the unit pixel elements 11 are arranged in a matrix over the entire screen of the display device. FIG. 1A shows emission by none of the EL elements (gradation “0”); FIG. 1 B—emission only by EL element 18 - 10 (gradation “1”); FIG. 1 C—emission only by EL elements 18 - 21 and 18 - 22 (gradation “2”); and FIG. 1 D—emission by all EL elements 18 - 21 , 18 - 10 and 18 - 22 (gradation “3”). As shown in FIGS. 1A-D, the luminous center 40 for each gradation is located at the same position as the luminous center of the luminescent portion (EL element 18 - 10 ), and configured such that it does not shift for each gradation. In other words, the luminescent portion corresponding to gradation “2” is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”. Furthermore, the luminescent portion corresponding to gradation “3” is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”. By arranging the luminescent portions point-symmetrically around a prescribed point provided at the center, easily obtained is a structure which prevents shifting of the luminous center 40 . Accordingly, even when the brightness of a displayed image is changed, unfavorable shifting of the displayed position does not take place. Therefore, the present invention solves disadvantages related to the picture quality, such as flickering of images, or impression of unnatural display or fatigue caused to the viewer. Furthermore, although respective EL elements are shaped in quadrilaterals (squares) in FIGS. 1A-D, they may be configured as circles or ovals. Moreover, by making the respective areas of EL elements 18 - 10 , 18 - 21 , and 18 - 22 uniform, light emission intensity for respective gradations may be increased or decreased linearly. (Embodiment 2) FIGS. 2A-D show a unit pixel 11 included in the display device. Each unit pixel is formed of EL elements 18 - 10 , 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 , and is a 3 bits-8 gradation display. In FIGS. 2A-D, EL element 18 - 10 is an EL element for 0-bit display. The on/off states of EL elements 18 - 21 and 18 - 22 are simultaneously controlled by the same driving transistor, and EL element 18 - 21 is a first EL element for 1-bit display and EL element 18 - 22 is a second EL element for 1-bit display. Similarly, the on/off states of EL elements 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 are simultaneously controlled by the same driving transistor. EL element 18 - 31 is a first EL element for 2-bit display, EL element 18 - 32 is a second EL element for 2-bit display, EL element 18 - 33 is a third EL element for 2-bit display, and EL element 18 - 34 is a fourth EL element for 2-bit display. Each EL element is driven and controlled by three scanning lines (for 0 to 2 bit display) which are not shown. Furthermore, although FIGS. 2A-D only show the unit pixel element 11 , in reality the unit pixel elements 11 are arranged in a matrix over the entire screen of the display device. FIG. 2A shows that none of the EL elements emit light (gradation “0”); FIG. 2 B—emission only by 0-bit display EL element 18 - 10 (gradation “1”); FIG. 2 C—emission by only 1-bit display EL elements 18 - 21 and 18 - 22 (gradation “2”); and FIG. 2D, emission by 0-bit and 1-bit display EL elements 18 - 10 , 18 - 21 and 18 - 22 (gradation “3”). Furthermore, FIG. 3A shows emission of only 2-bit display EL elements 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “4”); FIG. 3 B—emission of only 0-bit and 2-bit display EL elements 18 - 10 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “5”); FIG. 3 C—emission of only 1-bit and 2-bit display EL elements 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “6”); and FIG. 3D emission of all 0-bit, 1-bit and 2-bit display EL elements 18 - 10 , 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “7”). As shown in FIGS. 2A-D and 3 A-D, the luminous center 40 for each gradation is located at the same position as the center point of the luminescent portion (EL element 18 - 10 ), and structured so as to avoid shifting for each gradation. In other words, the luminescent portion corresponding to gradation “2” is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”. The luminescent portion corresponding to gradation “3” is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”, and the luminescent portion corresponding to gradation “7” is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”. By arranging luminescent portions point-symmetrically around a prescribed point provided at the center, easily obtained is a configuration which prevents shifting of the luminous center 40 . Accordingly, even when the brightness of a displayed image is changed, unfavorable shifting of the display position does not take place. Therefore, the present invention solves disadvantages related to the picture quality, such as flickering of images, or impression of unnatural display or fatigue caused to the viewer. Furthermore, although respective EL elements are shaped in quadrilaterals (squares) in FIGS. 2A-D, they may be configured as circles or ovals. Moreover, by making the respective areas of EL elements 18 - 10 , 18 - 21 , and 18 - 22 , for example, uniform, light emission intensity for respective gradations may be increased or decreased linearly. Furthermore, although the present embodiment is explained with eight gradations, different gradations may be obtained by adjusting the number of EL elements. The display device according to the present invention may be used for video cameras, digital cameras, car stereos, video CD players, portable terminals, laptop personal computers, etc.
Luminescent portions correspondent to each gradation are arranged point-symmetrically with one another around a prescribed position provided at the center, thereby forming a unit pixel element including a plurality of luminescent elements. Such a structure allows provision of a display device wherein a luminous center does not shift for each gradation. Accordingly, when the brightness of the displayed images is changed, unfavorable shifting of display positions does not take place. The present invention thus solves defects related to the picture quality, such as flickering of images, or an impression of unnatural display or fatigue caused to the viewer.
Identify the most important aspect in the document and summarize the concept accordingly.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention generally relates to a display device, especially to an improved technology of gradation display.", "Description of the Related Art TFT-ELDs, namely thin-film-transistor (TFT) driven electoroluminescent displays, which include electoroluminescent elements (EL elements) driven and controlled by thin film transistors, are considered as future potential displays due to their light weight, small size, high resolution, wide visual field, low electric consumption, etc.", "FIG. 4 is a circuit diagram of a conventional TFT-ELD, and FIG. 5 is a cross section of such TFT-ELD.", "FIG. 4 shows a unit pixel 11 of the TFT-ELD, a scanning line 12 , a signal line 13 , current supplying line 14 , a retention capacitor 15 , a selective transistor 16 , a driving transistor 17 , and an EL element 15 .", "As shown in FIG. 5, the driving transistor 17 for adjusting light emission intensity (gradation) of the EL element 18 is formed on a glass substrate 10 .", "A drain electrode of the driving transistor 17 is connected to a cathode (transparent electrode) 21 of the EL element 18 , and a source electrode is connected to the analog signal supply line 14 .", "The EL element 18 is formed of the anode 21 , a luminescent layer 22 , and an cathode 23 .", "The EL element 18 may be a inorganic electroluminescent element, a low-molecular organic electroluminescent element, or a high-molecular organic electroluminescent element.", "The selective transistor 16 includes a gate electrode connected to the scanning line 12 , a source electrode connected to a signal line 13 , and a drain electrode connected to a gate electrode of the driving transistor 17 .", "The retention capacitor 15 is provided between the analog signal supplying line 14 and the source electrode of the selective transistor 16 .", "In order to cause the EL element 18 to emit light in the aforementioned structure, the scanning line 12 and the signal line 13 are set at level “H”, and current is conducted between the drain and the source of the selective transistor 16 , whereby the driving transistor 17 is on state.", "An analog signal supplied from the analog supplying line 14 in this condition is delivered to the retention capacitor 15 and alters the conductance of the driving transistor 17 .", "As a result, the EL element 18 emits light with light emission intensity pursuant to the analog signal, thereby accomplishing gradations of light emission intensity.", "However, as a problem of the above-described.", "structure, resolution of the picture lowers due to the EL element 18 included in each pixel emitting light with unequal light emission intensity, especially in the middle gradation, because of the difference in the transistor properties of the driving transistor 17 .", "In order to solve this problem, the applicant of the present invention suggested in Japanese Patent Laid-Open Publication No. HEI 11-73158 a technology of displaying respective gradations by controlling on/off states of light emission of EL elements and changing the luminous area for each gradation.", "FIG. 6 is a circuit diagram of the TFT-ELD disclosed in said Laid-Open Publication.", "FIG. 6 shows an EL element included in each pixel, which is formed of EL elements 18 - 1 and 18 - 2 .", "Such structure allows display of four gradations by controlling on/off states of EL elements 18 - 1 and 18 - 2 respectively via a 2-bit signal line formed of signal lines 13 - 1 and 13 - 2 .", "More specifically, there are: gradation “0”, where neither EL element 18 - 1 nor 18 - 2 emits light;", "gradation “1”, where only EL element 18 - 1 emits light;", "gradation “2”, where only EL element 19 - 2 emits light;", "and gradation “3”, where both EL elements 18 - 1 and 18 - 2 emit light.", "Luminous areas of EL element 18 - 1 and EL element 18 - 2 are in a ratio of 1:2.", "As shown in FIG. 7, in the structure above, signals S, D 1 , and D 2 are respectively supplied to the scanning line 12 , signal line 13 - 1 and signal line 13 - 2 .", "When signal S is set at level “H”, current is conducted between the drain and the sources of selective transistors 16 - 1 and 16 - 2 .", "In FIG. 7, gradation “1”", "is obtained when signal S is set at level “H”, signal D 1 at level RHO, and signal D 2 at level “L.”", "As a consequence, driving transistor 17 - 1 is turned on, and transistor 17 - 2 is turned off, whereby only EL element 18 - 1 emits light.", "Furthermore, in order to realize gradation “2”, signal S should be set at level “H”, signal D 1 at level “L”, and signal D 2 at level “H.”", "By doing so, driving transistor 17 - 2 is turned on and transistor 17 - 1 is turned off, and consequently, only EL element 18 - 2 emits light.", "In this method, driving transistors 17 - 1 and 17 - 2 are to be regarded as either almost completely on state or almost completely off state.", "When driving transistors 17 - 1 and 17 - 2 are on state,resistance is negligibly small compared to the resistance of driving transistors 18 - 1 and 18 - 2 , such that the amount of current conducted through driving transistors 17 - 1 , 17 - 2 , 18 - 1 and 18 - 2 depends substantially on the resistance of driving transistors 18 - 1 and 18 - 2 alone.", "Accordingly, light emission intensity is never uneven due to the difference in the transistor properties of driving transistors 18 - 1 and 18 - 2 .", "Furthermore, when driving transistors 17 - 1 and 17 - 2 are off state, the voltage applied to EL elements 18 - 1 and 18 - 2 will be smaller than the threshold voltage, and driving transistors 18 - 1 and 19 - 2 , will not emit light at all.", "Therefore, also in this case, the light emission intensity of EL elements 18 - 1 and 18 - 2 is never uneven by the difference in the transistor properties of driving transistors 18 - 1 and 18 - 2 .", "However, as a disadvantage of the aforementioned structure, the luminous center (the average position of the luminescent portion) shifts for each gradation and visibility is thereby decreased.", "Characteristics of such disadvantage will be explained with reference to FIGS. 8A-D.", "FIG. 8C, for example, shows a luminous center 40 of the unit pixel element 11 .", "The EL element 18 - 1 shown with oblique lines means that no light is emitted, and the EL element 18 - 2 shown in white means that light is emitted.", "In FIG. 8A, the EL elements 18 - 1 , 18 - 2 do not emit light.", "In FIG. 8B, only EL element 18 - 1 emits light.", "In FIG. 8C, only EL element 18 - 2 emits light.", "Finally, in FIG. 8D, both EL elements 18 - 1 , 18 - 2 emit light.", "It is clear from these drawings that the position of the luminous center 40 changes for each gradation.", "As a consequence, when the brightness of a displayed image is changed, the position of the image shifts unfavorably.", "Furthermore, if the displayed image is actually observed here, the displayed image will be seen to flicker, causing an impression of unnatural display or fatigue to the viewer.", "SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to overcome such disadvantage and to provide a display device wherein a luminous center does not shift for each light emission gradation.", "In the present invention, in order to achieve said object, a unit pixel is formed of multiple EL elements whose luminescent portions corresponding to each gradation are arranged point-symmetrically with one another with respect to a prescribed point.", "Such structure allows provision of a display device wherein the position of a luminous center does not change for each gradation.", "“Prescribed position”", "here means, for example, a luminous center of the EL element upon realizing the gradation of minimum luminance.", "Furthermore, each electroluminescent element is preferably configured to have a state of “emission”", "or “non-emission.”", "By controlling on/off of the multiple Aluminescent elements, it is possible to prevent uneven aluminance caused by difference in the properties of luminescent elements.", "In order to achieve the structure above, electroluminescent elements may, for example, be used as luminescent elements, so that thin-film transistors may control the on/off states of light emission by the luminescent elements.", "BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-D are explanatory diagrams showing the emission state of the respective EL elements forming a unit pixel in the TFT-ELD according to embodiment 1;", "FIGS. 2A-D are explanatory diagrams showing a unit pixel in the TFT-ELD according to embodiment 2;", "FIGS. 3A-D are explanatory diagrams showing the emission state of the respective EL elements forming a unit pixel in the TFT-ELD according to embodiment 2;", "FIG. 4 is a circuit diagram of a unit pixel in a conventional TFT-ELD.", "FIG. 5 is a cross section of a unit pixel in a conventional TFT-ELD.", "FIG. 6 is a circuit diagram of a unit pixel in a conventional TFT-ELD;", "FIG. 7 is a timing chart indication a scanning line and a signal line of a conventional TFT-ELD;", "and FIGS. 8A-D are explanatory diagrams showing the light emission state of the EL elements forming a unit pixel of a conventional TFT-ELD.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIGS. 1A-D show a unit pixel 11 included in a display device according to the present invention.", "Each unit pixel has EL elements 18 - 10 , 18 - 21 and 18 - 22 , and is a 2 bit-4 gradation display.", "In FIG. 1A, for example, EL element 18 - 10 is an EL element for 0-bit display.", "The on/off states of EL elements 18 - 21 and 18 - 22 are simultaneously controlled by the same driving transistor, and EL element 18 - 21 is a first EL element for 1-bit display and EL element 18 - 22 is a second EL element for 1-bit display.", "Each EL element is driven and controlled by two scanning lines (for 0-bit and 1-bit display) which are not shown.", "Furthermore, although FIGS. 1A-D show only the unit pixel element 11 , in reality the unit pixel elements 11 are arranged in a matrix over the entire screen of the display device.", "FIG. 1A shows emission by none of the EL elements (gradation “0”);", "FIG. 1 B—emission only by EL element 18 - 10 (gradation “1”);", "FIG. 1 C—emission only by EL elements 18 - 21 and 18 - 22 (gradation “2”);", "and FIG. 1 D—emission by all EL elements 18 - 21 , 18 - 10 and 18 - 22 (gradation “3”).", "As shown in FIGS. 1A-D, the luminous center 40 for each gradation is located at the same position as the luminous center of the luminescent portion (EL element 18 - 10 ), and configured such that it does not shift for each gradation.", "In other words, the luminescent portion corresponding to gradation “2”", "is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1.”", "Furthermore, the luminescent portion corresponding to gradation “3”", "is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1.”", "By arranging the luminescent portions point-symmetrically around a prescribed point provided at the center, easily obtained is a structure which prevents shifting of the luminous center 40 .", "Accordingly, even when the brightness of a displayed image is changed, unfavorable shifting of the displayed position does not take place.", "Therefore, the present invention solves disadvantages related to the picture quality, such as flickering of images, or impression of unnatural display or fatigue caused to the viewer.", "Furthermore, although respective EL elements are shaped in quadrilaterals (squares) in FIGS. 1A-D, they may be configured as circles or ovals.", "Moreover, by making the respective areas of EL elements 18 - 10 , 18 - 21 , and 18 - 22 uniform, light emission intensity for respective gradations may be increased or decreased linearly.", "(Embodiment 2) FIGS. 2A-D show a unit pixel 11 included in the display device.", "Each unit pixel is formed of EL elements 18 - 10 , 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 , and is a 3 bits-8 gradation display.", "In FIGS. 2A-D, EL element 18 - 10 is an EL element for 0-bit display.", "The on/off states of EL elements 18 - 21 and 18 - 22 are simultaneously controlled by the same driving transistor, and EL element 18 - 21 is a first EL element for 1-bit display and EL element 18 - 22 is a second EL element for 1-bit display.", "Similarly, the on/off states of EL elements 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 are simultaneously controlled by the same driving transistor.", "EL element 18 - 31 is a first EL element for 2-bit display, EL element 18 - 32 is a second EL element for 2-bit display, EL element 18 - 33 is a third EL element for 2-bit display, and EL element 18 - 34 is a fourth EL element for 2-bit display.", "Each EL element is driven and controlled by three scanning lines (for 0 to 2 bit display) which are not shown.", "Furthermore, although FIGS. 2A-D only show the unit pixel element 11 , in reality the unit pixel elements 11 are arranged in a matrix over the entire screen of the display device.", "FIG. 2A shows that none of the EL elements emit light (gradation “0”);", "FIG. 2 B—emission only by 0-bit display EL element 18 - 10 (gradation “1”);", "FIG. 2 C—emission by only 1-bit display EL elements 18 - 21 and 18 - 22 (gradation “2”);", "and FIG. 2D, emission by 0-bit and 1-bit display EL elements 18 - 10 , 18 - 21 and 18 - 22 (gradation “3”).", "Furthermore, FIG. 3A shows emission of only 2-bit display EL elements 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “4”);", "FIG. 3 B—emission of only 0-bit and 2-bit display EL elements 18 - 10 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “5”);", "FIG. 3 C—emission of only 1-bit and 2-bit display EL elements 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “6”);", "and FIG. 3D emission of all 0-bit, 1-bit and 2-bit display EL elements 18 - 10 , 18 - 21 , 18 - 22 , 18 - 31 , 18 - 32 , 18 - 33 and 18 - 34 (gradation “7”).", "As shown in FIGS. 2A-D and 3 A-D, the luminous center 40 for each gradation is located at the same position as the center point of the luminescent portion (EL element 18 - 10 ), and structured so as to avoid shifting for each gradation.", "In other words, the luminescent portion corresponding to gradation “2”", "is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1.”", "The luminescent portion corresponding to gradation “3”", "is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1”, and the luminescent portion corresponding to gradation “7”", "is located point-symmetrically with respect to the luminescent portion corresponding to gradation “1.”", "By arranging luminescent portions point-symmetrically around a prescribed point provided at the center, easily obtained is a configuration which prevents shifting of the luminous center 40 .", "Accordingly, even when the brightness of a displayed image is changed, unfavorable shifting of the display position does not take place.", "Therefore, the present invention solves disadvantages related to the picture quality, such as flickering of images, or impression of unnatural display or fatigue caused to the viewer.", "Furthermore, although respective EL elements are shaped in quadrilaterals (squares) in FIGS. 2A-D, they may be configured as circles or ovals.", "Moreover, by making the respective areas of EL elements 18 - 10 , 18 - 21 , and 18 - 22 , for example, uniform, light emission intensity for respective gradations may be increased or decreased linearly.", "Furthermore, although the present embodiment is explained with eight gradations, different gradations may be obtained by adjusting the number of EL elements.", "The display device according to the present invention may be used for video cameras, digital cameras, car stereos, video CD players, portable terminals, laptop personal computers, etc." ]
TECHNICAL FIELD The invention relates to a method and accessory for the contamination-free keeping of stoppers used in medical care. The fitting comprises a stopper or carrier which is temporarily placed upon syringes or other equipment to prevent entry of contamination while awaiting use of the syringe. BACK GROUND ART The medical care needs often to establish connection to the patient's hypodermic tissues via syringes, tubes or containers of different kinds. The connection must be established with total sterility. Leakage and unwanted contact must be avoided as far as possible. Such unintended contact, especially with blood and blood vessels, may involve a very serious risk of infection. Examples of treatments requiring blood vessel connection are blood transfusion inclusive blood giving, blood sampling assisted by test containers under negative pressure, and intravenous supply of medicine, nourishment or just liquid for blood volume expansion, commonly called a drip. A frequently used syringe for insertion in blood vessels of different kinds has a tube body with a channel that continues in a thin and soft plastic tube. The rear port of the tube body is shaped as a conical cavity and, at the beginning, closed by a hollow needle and a needle body, the rear part of which has a transparent signal chamber, which gets filled with blood, when satisfactory blood vessel contact has been established. The rear wall of the signal chamber is liquid-tight and prevents blood shedding through the rear opening of the needle body. This opening is used for temporary placement of a stopper intended for tightening the rear port of the tube body, when the needle has been withdrawn. To establish a blood vessel connection one choses a suitable, superficial blood vessel (vein or artery depending upon type of treatment) and tries to direct the tip of the puncture needle to penetrate the skin just over the chosen blood vessel, so that the tip hits the vessel centrally and, after penetration of the vessel wall, with the plastic tube can be directed into the blood path. When the above mentioned transparent room behind the needle starts filling with blood, the syringe is advanced a little (about 2 mm) to ensure complete penetration of the vessel wall. Then the needle body with the belonging puncture needle is kept still, while the tube is advanced so that the needle tip no longer is in front of the end of the plastic tube. This is done to prevent the needle tip from hurting the vessel wall. Finally the syringe is advanced to its desired position and kept there. After that the puncture-needle is withdrawn. To prevent blood shedding through the rear opening of the tube body, which has been tightened by the needle body, the withdrawal is begun by the operator by compressing, with one of his or her hands, the skin area over the tip of the plastic tube, until he or she has withdrawn the puncture needle and applied the intended stopper in the rear end of the tube body. This is a critical moment concerning leakage. As seen above the operator has just one hand free (usually the right hand). The other hand is used for tissue compressing. With the free hand the operator has to loosen the stopper from the needle body and, without contaminating the stopper, move it to the rear end of the tube body. The needle body may have to be let free for grip changing before the stopper can be removed. The operation is not simple even under good circumstances in a ward unit. If it instead has to be done in a forth-rushing ambulance by personnel with little syringe handling education, the difficulties become even worse. The risk is large that the needle body rolls away. The risk is also large that the stopper is dropped and lost and/or becomes contaminated before getting placed in the rear port of the tube body. In both cases the operator needs help, if not the whole operation should have to be repeated with a new sterile syringe. Trials have been made earlier (The Swedish laid open publication no 355 946) to place the tube body stopper at one of the tube body's wings. This placing has shown to be less convenient, as the stopper gets in the way and hampers the vessel puncture. The problem of sterile between-handling is not limited to blood vessel entries. It appears in a row of clinical situations for example irrigation (rinsing) at surgical operations and respirator treatments to mention a few examples. The circumstances at these situations are in high degree analogous with those at intravenous entry and the more detailed description is therefore limited to the circumstances at venous punctures. SUMMARY OF THE INVENTION The purpose of this invention is to solve the problem of between keeping and availability of stoppers under circumstances preventing contamination. According to this new method the stopper is coupled to the device so it does not hamper actual operation, is nearby and can be easily loosened and placed in the intended opening, without the risks mentioned above of getting lost or contaminated. Further the invention concerns fittings to syringes of the type described above, i.e. consisting of a tube body and a needle body and other medical care devices with similar stoppers. The fitting may consist of a stopper designed for coupling to a recess in another existing stopper or a carrier, which may be combined with a stopper. The carrier has a lower part, which may be designed as a substitute for an existing stopper, a mid-piece, which is inserted in or over an existing stopper, a rider for placing over curved surfaces or a plane foot for fastening at suitable surfaces. The requirement, that the coupling must be done without letting the stopper hamper the handling of the syringe, rules out earlier mentioned placing at one wing of the tube body. If the syringe is provided with an upper port and a stopper belonging to this port placing at its upper surface is preferred. Concerning syringes that do not have suitable surfaces for the temporary placing of the end stopper the stopper of the invention is combined with a carrier for instance in the shape of a rider, which can be placed at a suitable location at the tube body. Altered design of the tube body may also provide new surfaces suitable for temporary placing of the end stopper. The same is valid for other equipment, too. For devices with a design that makes riders not suitable, the rider can be substituted with a carrier-foot according to the Swedish patent application no 9500800-9. The coupling between the tube body and the stopper must be done so that no increased risks of contaminating surfaces with potential blood contact are produced. One possibility is that the coupling is done when the sterile packed syringe is taken from the package and before the surface, where the coupling takes place, has been touched. Another possibility is to protect the surface with a protecting tape until the coupling moment. The first possibility is preferred if stopper and syringe is in separate packages. The second may be of interest if the fitting is by-packed the syringe. Coupling to an existing upper stopper can be done via a slender outgrowth 2.212' at the cone-formed closing part of the end stopper 2.212 designed to fit the recess in the upper tube body stopper 2.31 or another suitably seized recess at the tube body. The outgrowth may with advantage be designed as a rod passing through a bore in the stopper and being pressed in when the coupling is done. Conical stoppers of this kind are often used in the medical care and are the subject of a standard that is usually called Luer-cone (ISO-standard 594/1-2). An alternative to using a stopper as above is that the fitting consists of stopper 2.31' that substitutes the upper tube body stopper 2.31. The upper part of the substitute stopper is designed so that its form functionally matches the rear opening of the needle body and thus is suitable to serve as "parking place" for the existing end stopper. To prevent misunderstanding it should be remarked that the rear opening of the needle body is a blind port, the sole function of which is to keep and protect the end stopper from contamination, until it is used for closing the rear port of the tube body. All designs that fulfill this purpose thus match the rear opening of the needle body from the functional point of view. It may for instances be an edge that surrounds a recess fitting the protruding conical closing part 2.212 of the end stopper 2.21 or a cone-formed, inner recess and an outer tube-formed part that together match the rear opening of the needle body, or an essentially conical tube-piece that by spring force engages the inner wall of the end stopper's mantle. Different variants and combinations of these designs may be used for different syringe types. Besides these already mentioned arrangements one may also use a design with a slitted or bead provided tube-piece, which by spring-force grasps around the outer mantle of the end-stopper. As an alternative to modification of the upper tube body stopper a mid-piece may be used, which has a lover part with an outgrowth of the type mentioned for the end-stopper or a lover tube-formed part adapted for a suitable firm and flexible fit around the upper tube body stopper's upper part and an upper part that functionally matches the rear opening of the needle body, i.e. is designed analogously with the upper part of the alternative upper stopper described. If the fitting is sold separately, the design with a tube-part grasping around the outer mantle of the end-stopper may be of special interest, as it, with relative ease, can be made to fit most of the syringe types that are present on the market. Besides this design is less demanding of complete sterility at the handling, as no surfaces that may meet blood have to be touched. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a syringe with an upper port. FIG. 2a is side view of a syringe without upper port and provided with a rider for temporary placing of a tube body stopper of the invention. FIG. 2b is a plan view of a syringe without an upper port and provided with a rider for temporary placing of a tube body stopper of the invention. FIG. 3a depicts a cross-sectional view of the upper part of a typical prior art stopper. FIG. 3b depicts a partially-sectioned side view of the stopper of FIG. 3a. FIG. 4 shows a design of to FIG. 4a depicts a cross-sectional view of the upper part of a stopper according to the invention. FIG. 4b depicts a partially-sectioned side view of the stopper of FIG. 4a. FIG. 5 shows a section of a rider intended for use on syringes according to FIG. 2a along the line 5--5. FIG. 6 shows a syringe like FIG. 1 provided with a stopper according to the invention placed upon the upper tube body stopper. FIG. 7 shows a syringe like FIG. 1 provided with a variant of an upper tube body stopper according to the invention. FIG. 8a depicts a partially sectioned side view of a mid-piece intended for use on syringes with an upper stopper and an upwards open recess in this stopper. FIG. 8b depicts a cross-sectional view of the mid-piece of FIG. 8a. FIG. 9a depicts a partially sectioned side view of a mid-piece intended for use at syringes with an upper stopper without upwards open recess. FIG. 9b depicts a cross-sectional view of the mid-piece of FIG. 9a. FIG. 10a depicts a partially sectioned side view of a carrier-foot, which can be used for application at equipment with plane surfaces. FIG. 10b depicts a plan view of the carrier foot of FIG. 10a. FIG. 11a depicts a cross-sectional view of the upper part of a typical prior art stopper. FIG. 11b depicts a partially sectioned side view of the prior art stopper of FIG. 11a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one of the often used syringes for entry in blood vessels of different kinds. The syringe consists of a tube body 2 with a channel that continues in a thin and soft plastic tube 2.1. The rear opening of the tube body 2.2 is shaped as a conical cavity and, from the beginning, closed by the tube-formed needle 1.1 and the needle body 1, which has been marked by slanting lines. The rear part of the needle body has a transparent signal chamber 1.2, which gets filled with blood, when satisfactory blood path contact has been established. The rear wall 1.21 of the signal chamber 1.2 is liquid-tight and prevents blood shedding out of the rear opening 1.3 of the needle body. This opening is used for temporary placing of the stopper 2.31 intended for closing the rear opening 2.2 of the tube body, when the needle has been withdrawn. Beside the opening 2.2 the tube body 2 has another opening 2.3 used for connection to injectors etc. This opening in closed by the stopper 2.31, which centrally has an upwards open axial recess 2.311. Such recesses are, as a rule, present at stoppers of similar kinds and serve to prevent dimension changes at manufacturing by pressure moulding. FIGS. 2a and 2b shows another often used syringe without upper port. Apart from that and the fact that it has been provided with a rider 3, placed over the tube body abreast with its wings and designed with a recess 3.1 for the stopper 2.2, the design of this syringe corresponds with the one according to FIG. 1. FIGS. 3a, 3b, 11a and 11b show the stoppers, usually belonging to the syringes of FIG. 1 and 2, in larger scale. FIGS. 4a and 4b shows one design of a stopper according to the invention. In both cases the stopper has a protruding, central, slightly cone-formed part 2.212, the purpose of which is closing of the slightly conical opening 2.2 of the tube body 2 and a protecting, cylinder-formed mantle 2.213, which depending upon the supplier of the syringe may have different length and sometimes covers the closing part entirely. According to the design of FIGS. 4a and 4b the stopper is provided with a tapering outgrowth (length about twice the diameter) 2.212' of the conical part 2.212. The diamete r of the outgrowth is chosen so it with moderately firm coupling can be inserted into the recess 2.311 of the stopper 2.31. As mentioned above the outgrowth may with advantage be designed as a rod passing trough a bore in the stopper 2.31 and being pressed in, when the coupling is done. FIG. 5 shows a rider, which can be used to get a suitable place for temporary keeping of the end-stopper of syringes lacking upper port. The lower part has a recess 3.2 in the shape of a cut cylinder with part of the mantle removed. The recess is made so the rider can be placed upon a syringe like FIG. 2 abreast with the wings. The upper part of the rider can have a recess 3.1 adapted for receiving a modified stopper or a mid-piece as above, which here accompanies the rider. Another better alternative is, of course, an upper part with principally the same design as the upper part of the mid-piece. FIGS. 8a and 8b, 9a and 9b show two different designs of mid-pieces that have been found especially suitable. In the FIGS. 4.1 stands for the upper part and 4.2 respectively. 4.2' for the lower part. In FIGS. 8a and 8b the lower part 4.2 consists solely of an outgrowth adapted to fit into the recess of the upper stopper. In FIGS. 9a and 9b the lower part has been designed to fit over the upper stopper 2.31 even if it is lacking upwards open recess. Upper stoppers have as a rule a "strap" 2.311 that anchors it to the tube body. The mantle of the lower part of the mid-piece is therefore provided with a longitudinal recess 4.211. FIGS. 10a and 10b shows a carrier-foot 5 that with advantage may be used at equipment with plane surfaces near the place, where the stopper is used. The footplate 5.2 should be prepared so it, after removing a protecting film, sticks to the surface permanently or temporary depending on the need. The upper part 5.1 may with advantage be designed analogously with the mid-pieces of the FIGS. 8 and 9. Riders according to FIG. 5, carrier-feet as in FIGS. 10a and 10b and mid-pieces of the types shown in FIGS. 8a, 8b, 9a and 9b can be designed s o they can be used without sterilizing. A condition for this is that they in a reliable way can be handled without making contact between surfaces that may meet blood and tissues and not sterilised surfaces. To facilitate insertion of the stopper 2.21 in the upper part, without making unintended contacts, the upper part is provided with a guide rail 4.11 that makes the insertion of the stopper easier. To amend the fit between the mid-piece and the upper stopper of the tube body the lower part of the mantle 4.22 may be provided with yielding edgings 4.221. Similar edgings may be used for the upper part too. Another alternative to effect required, firm keeping, without causing problems at loosening, is longitudinal notches or beads at the inner side of the tubes. The same is true, if applicable, for carrier-stoppers, riders and carrier-feet. The new accessory may be marketed as a separate unit or by-packed the syringe or device. As already mentioned the rear opening of the needle body is a blind port, the sole purpose of which is keeping and protecting the end-stopper. A modified stopper or a mid-piece with an inserted stopper may be placed there, if the rear end of the needle body is modified. Another possibility is that a mid-piece is placed in the end-stopper's recess and moved to the upper stopper at the start of the operation. The proposed possibilities are examples and should not be considered as limiting the invention.
An accessory for temporary, contamination-free holding of closing stoppers used for syringes and other medical care devices, where the accessory comprises a stopper designed for coupling to a recess in another existing stopper or a carrier that can be combined with a stopper. The carrier has a lower part, which may be designed as a substitute for an existing stopper; a mid-piece, which is inserted in or over an existing stopper; a rider for placing over a curved surface such as a syringe body; or a carrier-foot for fastening onto suitable surfaces.
Briefly outline the background technology and the problem the invention aims to solve.
[ "TECHNICAL FIELD The invention relates to a method and accessory for the contamination-free keeping of stoppers used in medical care.", "The fitting comprises a stopper or carrier which is temporarily placed upon syringes or other equipment to prevent entry of contamination while awaiting use of the syringe.", "BACK GROUND ART The medical care needs often to establish connection to the patient's hypodermic tissues via syringes, tubes or containers of different kinds.", "The connection must be established with total sterility.", "Leakage and unwanted contact must be avoided as far as possible.", "Such unintended contact, especially with blood and blood vessels, may involve a very serious risk of infection.", "Examples of treatments requiring blood vessel connection are blood transfusion inclusive blood giving, blood sampling assisted by test containers under negative pressure, and intravenous supply of medicine, nourishment or just liquid for blood volume expansion, commonly called a drip.", "A frequently used syringe for insertion in blood vessels of different kinds has a tube body with a channel that continues in a thin and soft plastic tube.", "The rear port of the tube body is shaped as a conical cavity and, at the beginning, closed by a hollow needle and a needle body, the rear part of which has a transparent signal chamber, which gets filled with blood, when satisfactory blood vessel contact has been established.", "The rear wall of the signal chamber is liquid-tight and prevents blood shedding through the rear opening of the needle body.", "This opening is used for temporary placement of a stopper intended for tightening the rear port of the tube body, when the needle has been withdrawn.", "To establish a blood vessel connection one choses a suitable, superficial blood vessel (vein or artery depending upon type of treatment) and tries to direct the tip of the puncture needle to penetrate the skin just over the chosen blood vessel, so that the tip hits the vessel centrally and, after penetration of the vessel wall, with the plastic tube can be directed into the blood path.", "When the above mentioned transparent room behind the needle starts filling with blood, the syringe is advanced a little (about 2 mm) to ensure complete penetration of the vessel wall.", "Then the needle body with the belonging puncture needle is kept still, while the tube is advanced so that the needle tip no longer is in front of the end of the plastic tube.", "This is done to prevent the needle tip from hurting the vessel wall.", "Finally the syringe is advanced to its desired position and kept there.", "After that the puncture-needle is withdrawn.", "To prevent blood shedding through the rear opening of the tube body, which has been tightened by the needle body, the withdrawal is begun by the operator by compressing, with one of his or her hands, the skin area over the tip of the plastic tube, until he or she has withdrawn the puncture needle and applied the intended stopper in the rear end of the tube body.", "This is a critical moment concerning leakage.", "As seen above the operator has just one hand free (usually the right hand).", "The other hand is used for tissue compressing.", "With the free hand the operator has to loosen the stopper from the needle body and, without contaminating the stopper, move it to the rear end of the tube body.", "The needle body may have to be let free for grip changing before the stopper can be removed.", "The operation is not simple even under good circumstances in a ward unit.", "If it instead has to be done in a forth-rushing ambulance by personnel with little syringe handling education, the difficulties become even worse.", "The risk is large that the needle body rolls away.", "The risk is also large that the stopper is dropped and lost and/or becomes contaminated before getting placed in the rear port of the tube body.", "In both cases the operator needs help, if not the whole operation should have to be repeated with a new sterile syringe.", "Trials have been made earlier (The Swedish laid open publication no 355 946) to place the tube body stopper at one of the tube body's wings.", "This placing has shown to be less convenient, as the stopper gets in the way and hampers the vessel puncture.", "The problem of sterile between-handling is not limited to blood vessel entries.", "It appears in a row of clinical situations for example irrigation (rinsing) at surgical operations and respirator treatments to mention a few examples.", "The circumstances at these situations are in high degree analogous with those at intravenous entry and the more detailed description is therefore limited to the circumstances at venous punctures.", "SUMMARY OF THE INVENTION The purpose of this invention is to solve the problem of between keeping and availability of stoppers under circumstances preventing contamination.", "According to this new method the stopper is coupled to the device so it does not hamper actual operation, is nearby and can be easily loosened and placed in the intended opening, without the risks mentioned above of getting lost or contaminated.", "Further the invention concerns fittings to syringes of the type described above, i.e. consisting of a tube body and a needle body and other medical care devices with similar stoppers.", "The fitting may consist of a stopper designed for coupling to a recess in another existing stopper or a carrier, which may be combined with a stopper.", "The carrier has a lower part, which may be designed as a substitute for an existing stopper, a mid-piece, which is inserted in or over an existing stopper, a rider for placing over curved surfaces or a plane foot for fastening at suitable surfaces.", "The requirement, that the coupling must be done without letting the stopper hamper the handling of the syringe, rules out earlier mentioned placing at one wing of the tube body.", "If the syringe is provided with an upper port and a stopper belonging to this port placing at its upper surface is preferred.", "Concerning syringes that do not have suitable surfaces for the temporary placing of the end stopper the stopper of the invention is combined with a carrier for instance in the shape of a rider, which can be placed at a suitable location at the tube body.", "Altered design of the tube body may also provide new surfaces suitable for temporary placing of the end stopper.", "The same is valid for other equipment, too.", "For devices with a design that makes riders not suitable, the rider can be substituted with a carrier-foot according to the Swedish patent application no 9500800-9.", "The coupling between the tube body and the stopper must be done so that no increased risks of contaminating surfaces with potential blood contact are produced.", "One possibility is that the coupling is done when the sterile packed syringe is taken from the package and before the surface, where the coupling takes place, has been touched.", "Another possibility is to protect the surface with a protecting tape until the coupling moment.", "The first possibility is preferred if stopper and syringe is in separate packages.", "The second may be of interest if the fitting is by-packed the syringe.", "Coupling to an existing upper stopper can be done via a slender outgrowth 2.212'", "at the cone-formed closing part of the end stopper 2.212 designed to fit the recess in the upper tube body stopper 2.31 or another suitably seized recess at the tube body.", "The outgrowth may with advantage be designed as a rod passing through a bore in the stopper and being pressed in when the coupling is done.", "Conical stoppers of this kind are often used in the medical care and are the subject of a standard that is usually called Luer-cone (ISO-standard 594/1-2).", "An alternative to using a stopper as above is that the fitting consists of stopper 2.31'", "that substitutes the upper tube body stopper 2.31.", "The upper part of the substitute stopper is designed so that its form functionally matches the rear opening of the needle body and thus is suitable to serve as "parking place"", "for the existing end stopper.", "To prevent misunderstanding it should be remarked that the rear opening of the needle body is a blind port, the sole function of which is to keep and protect the end stopper from contamination, until it is used for closing the rear port of the tube body.", "All designs that fulfill this purpose thus match the rear opening of the needle body from the functional point of view.", "It may for instances be an edge that surrounds a recess fitting the protruding conical closing part 2.212 of the end stopper 2.21 or a cone-formed, inner recess and an outer tube-formed part that together match the rear opening of the needle body, or an essentially conical tube-piece that by spring force engages the inner wall of the end stopper's mantle.", "Different variants and combinations of these designs may be used for different syringe types.", "Besides these already mentioned arrangements one may also use a design with a slitted or bead provided tube-piece, which by spring-force grasps around the outer mantle of the end-stopper.", "As an alternative to modification of the upper tube body stopper a mid-piece may be used, which has a lover part with an outgrowth of the type mentioned for the end-stopper or a lover tube-formed part adapted for a suitable firm and flexible fit around the upper tube body stopper's upper part and an upper part that functionally matches the rear opening of the needle body, i.e. is designed analogously with the upper part of the alternative upper stopper described.", "If the fitting is sold separately, the design with a tube-part grasping around the outer mantle of the end-stopper may be of special interest, as it, with relative ease, can be made to fit most of the syringe types that are present on the market.", "Besides this design is less demanding of complete sterility at the handling, as no surfaces that may meet blood have to be touched.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a syringe with an upper port.", "FIG. 2a is side view of a syringe without upper port and provided with a rider for temporary placing of a tube body stopper of the invention.", "FIG. 2b is a plan view of a syringe without an upper port and provided with a rider for temporary placing of a tube body stopper of the invention.", "FIG. 3a depicts a cross-sectional view of the upper part of a typical prior art stopper.", "FIG. 3b depicts a partially-sectioned side view of the stopper of FIG. 3a.", "FIG. 4 shows a design of to FIG. 4a depicts a cross-sectional view of the upper part of a stopper according to the invention.", "FIG. 4b depicts a partially-sectioned side view of the stopper of FIG. 4a.", "FIG. 5 shows a section of a rider intended for use on syringes according to FIG. 2a along the line 5--5.", "FIG. 6 shows a syringe like FIG. 1 provided with a stopper according to the invention placed upon the upper tube body stopper.", "FIG. 7 shows a syringe like FIG. 1 provided with a variant of an upper tube body stopper according to the invention.", "FIG. 8a depicts a partially sectioned side view of a mid-piece intended for use on syringes with an upper stopper and an upwards open recess in this stopper.", "FIG. 8b depicts a cross-sectional view of the mid-piece of FIG. 8a.", "FIG. 9a depicts a partially sectioned side view of a mid-piece intended for use at syringes with an upper stopper without upwards open recess.", "FIG. 9b depicts a cross-sectional view of the mid-piece of FIG. 9a.", "FIG. 10a depicts a partially sectioned side view of a carrier-foot, which can be used for application at equipment with plane surfaces.", "FIG. 10b depicts a plan view of the carrier foot of FIG. 10a.", "FIG. 11a depicts a cross-sectional view of the upper part of a typical prior art stopper.", "FIG. 11b depicts a partially sectioned side view of the prior art stopper of FIG. 11a.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows one of the often used syringes for entry in blood vessels of different kinds.", "The syringe consists of a tube body 2 with a channel that continues in a thin and soft plastic tube 2.1.", "The rear opening of the tube body 2.2 is shaped as a conical cavity and, from the beginning, closed by the tube-formed needle 1.1 and the needle body 1, which has been marked by slanting lines.", "The rear part of the needle body has a transparent signal chamber 1.2, which gets filled with blood, when satisfactory blood path contact has been established.", "The rear wall 1.21 of the signal chamber 1.2 is liquid-tight and prevents blood shedding out of the rear opening 1.3 of the needle body.", "This opening is used for temporary placing of the stopper 2.31 intended for closing the rear opening 2.2 of the tube body, when the needle has been withdrawn.", "Beside the opening 2.2 the tube body 2 has another opening 2.3 used for connection to injectors etc.", "This opening in closed by the stopper 2.31, which centrally has an upwards open axial recess 2.311.", "Such recesses are, as a rule, present at stoppers of similar kinds and serve to prevent dimension changes at manufacturing by pressure moulding.", "FIGS. 2a and 2b shows another often used syringe without upper port.", "Apart from that and the fact that it has been provided with a rider 3, placed over the tube body abreast with its wings and designed with a recess 3.1 for the stopper 2.2, the design of this syringe corresponds with the one according to FIG. 1. FIGS. 3a, 3b, 11a and 11b show the stoppers, usually belonging to the syringes of FIG. 1 and 2, in larger scale.", "FIGS. 4a and 4b shows one design of a stopper according to the invention.", "In both cases the stopper has a protruding, central, slightly cone-formed part 2.212, the purpose of which is closing of the slightly conical opening 2.2 of the tube body 2 and a protecting, cylinder-formed mantle 2.213, which depending upon the supplier of the syringe may have different length and sometimes covers the closing part entirely.", "According to the design of FIGS. 4a and 4b the stopper is provided with a tapering outgrowth (length about twice the diameter) 2.212'", "of the conical part 2.212.", "The diamete r of the outgrowth is chosen so it with moderately firm coupling can be inserted into the recess 2.311 of the stopper 2.31.", "As mentioned above the outgrowth may with advantage be designed as a rod passing trough a bore in the stopper 2.31 and being pressed in, when the coupling is done.", "FIG. 5 shows a rider, which can be used to get a suitable place for temporary keeping of the end-stopper of syringes lacking upper port.", "The lower part has a recess 3.2 in the shape of a cut cylinder with part of the mantle removed.", "The recess is made so the rider can be placed upon a syringe like FIG. 2 abreast with the wings.", "The upper part of the rider can have a recess 3.1 adapted for receiving a modified stopper or a mid-piece as above, which here accompanies the rider.", "Another better alternative is, of course, an upper part with principally the same design as the upper part of the mid-piece.", "FIGS. 8a and 8b, 9a and 9b show two different designs of mid-pieces that have been found especially suitable.", "In the FIGS. 4.1 stands for the upper part and 4.2 respectively.", "4.2'", "for the lower part.", "In FIGS. 8a and 8b the lower part 4.2 consists solely of an outgrowth adapted to fit into the recess of the upper stopper.", "In FIGS. 9a and 9b the lower part has been designed to fit over the upper stopper 2.31 even if it is lacking upwards open recess.", "Upper stoppers have as a rule a "strap"", "2.311 that anchors it to the tube body.", "The mantle of the lower part of the mid-piece is therefore provided with a longitudinal recess 4.211.", "FIGS. 10a and 10b shows a carrier-foot 5 that with advantage may be used at equipment with plane surfaces near the place, where the stopper is used.", "The footplate 5.2 should be prepared so it, after removing a protecting film, sticks to the surface permanently or temporary depending on the need.", "The upper part 5.1 may with advantage be designed analogously with the mid-pieces of the FIGS. 8 and 9.", "Riders according to FIG. 5, carrier-feet as in FIGS. 10a and 10b and mid-pieces of the types shown in FIGS. 8a, 8b, 9a and 9b can be designed s o they can be used without sterilizing.", "A condition for this is that they in a reliable way can be handled without making contact between surfaces that may meet blood and tissues and not sterilised surfaces.", "To facilitate insertion of the stopper 2.21 in the upper part, without making unintended contacts, the upper part is provided with a guide rail 4.11 that makes the insertion of the stopper easier.", "To amend the fit between the mid-piece and the upper stopper of the tube body the lower part of the mantle 4.22 may be provided with yielding edgings 4.221.", "Similar edgings may be used for the upper part too.", "Another alternative to effect required, firm keeping, without causing problems at loosening, is longitudinal notches or beads at the inner side of the tubes.", "The same is true, if applicable, for carrier-stoppers, riders and carrier-feet.", "The new accessory may be marketed as a separate unit or by-packed the syringe or device.", "As already mentioned the rear opening of the needle body is a blind port, the sole purpose of which is keeping and protecting the end-stopper.", "A modified stopper or a mid-piece with an inserted stopper may be placed there, if the rear end of the needle body is modified.", "Another possibility is that a mid-piece is placed in the end-stopper's recess and moved to the upper stopper at the start of the operation.", "The proposed possibilities are examples and should not be considered as limiting the invention." ]
CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority under 35 U.S.C. §119 of Japanese Application No. 2014-266856, filed on Dec. 27, 2014, and Japanese Application No. 2015-140317, filed on Jul. 14, 2015, the disclosures of which are expressly incorporated by reference herein in their entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scale fixating device. Specifically, the present invention relates to a device for fixating a scale enabling accuracy of a scale to be maintained when mounting and fixating an elongated scale to an object. 2. Description of Related Art As a scale in an instrument measuring length (linear encoder), a tape scale formed in a thin tape shape made of glass or a metal is known. (Japanese Patent Laid-open Publication No. 2011-237310, Japanese Patent No. 4,477,442, Japanese Patent Laid-open Publication No. 2013-7718, and Japanese Patent Laid-open Publication No. S63-252213.) The tape scale provides advantages such as easy lengthening, easy transportation, and simple mounting. When a tape scale is mounted and fixated to an object, tension is applied in a measurement axis direction. For example, a first end of the tape scale is unmovably fixated to the object and a second end of the tape scale is fixated to a sliding member allowing the second end of the tape scale to move relative to the object. In addition, the tension is applied to the sliding member so as to pull the second end of the tape scale. As a result, even in a case where the tape scale is expanded/contracted by a change in temperature, the tape scale maintains straightness. Generally, a guarantee temperature is set from 0° C. to 50° C. and the tension is applied such that the straightness is maintained within this range. For example, when the tape scale is made of a SUS material, there is about 10.5 μm expansion/contraction per 1 meter with a change in temperature of 1° C. In order to absorb the expansion/contraction, when the encoder is installed at a temperature of 20° C., a pull of 250 μm per 1 meter is required. As described above, the predetermined tension is applied to the tape scale via the sliding member, however, when inspected after some time following the encoder installation, the tension is often changed. In other words, the sliding member is pulled by the predetermined amount (250 μm per 1 meter), however, a position of the sliding member is displaced from an initial installed position when inspected after some time. A user of the encoder does not check if the tension of the tape scale is appropriate or not once the encoder is installed, which may lead to a measurement error. Displacement does not occur in all cases and although a cause was unknown, was thought to be a difference in ability during encoder installation. The present inventors have carried out extensive studies and succeeded in shedding light on a fundamental cause, as well as devising a countermeasure to achieve the present disclosure. SUMMARY OF THE INVENTION An advantage of the present disclosure is to provide a scale fixating device capable of maintaining accuracy of a scale while preventing tension of the scale from changing. The scale fixating device according to the present disclosure installs and fixates the scale to an object and includes a fixing block part unmovably fixating a first end of the scale to the object and a pulling block part fixating a second end of the scale to an object while pulling the second end of the scale. The pulling block part includes a fixated base fixated to the object, a slide part holding the second end of the scale and installed slidably with respect to the fixated base, and a pulling mechanism (also referred to as a “puller”) having a first end engaged to the slide part and a second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base. A surface of the slide part contacting the fixated base is beveled. The scale fixating device according to the present disclosure installs and fixates the scale to the object and includes the fixing block part unmovably fixating the first end of the scale to the object and the pulling block part fixating the second end of the scale to the object while pulling the second end of the scale. The pulling block part includes the fixated base fixated to the object, the slide part holding the second end of the scale and installed slidably with respect to the fixated base, and the pulling mechanism having the first end engaged to the slide part and the second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base. At least one of a mutual contact surface of the slide part and a mutual contact surface of the fixated base is mirror finished. The scale fixating device according to the present disclosure installs and fixates the scale to the object and includes the fixing block part unmovably fixating the first end of the scale to the object and the pulling block part fixating the second end of the scale to the object while pulling the second end of the scale. The pulling block part includes the fixated base fixated to the object, the slide part holding the second end of the scale and installed slidably with respect to the fixated base, and the pulling mechanism having the first end engaged to the slide part and the second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base. One of the mutual contact surface of the slide part and the mutual contact surface of the fixated base has a rough surface while the other is covered in a resin film. In the present disclosure, the slide part includes a elongated aperture and is pressed against the fixated base with a first screw inserted through the elongated aperture and screwed to the fixated base, and a first flanged sleeve is preferably mounted between the first screw and the elongated aperture. In the present disclosure, the second end of the scale is screwed to the slide part with a second screw and a second flanged sleeve is preferably installed between the second screw and the second end of the scale. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present disclosure, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein: FIG. 1 is an exploded perspective view of a tape scale fixating device; FIG. 2 is an external view of the tape scale fixating device; FIG. 3 is a cross-sectional view of a pulling block part; FIG. 4 is an expanded view of a fixated base and a slide part; FIG. 5 illustrates a beveled slide part; FIG. 6 illustrates a flanged sleeve; FIG. 7 illustrates assessment results; and FIG. 8 illustrates a case where a base portion has a rough surface and a thin film is formed on a holding piece. DETAILED DESCRIPTION OF THE INVENTION The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the forms of the present invention may be embodied in practice. An embodiment of the present disclosure is shown and described with reference to numerals given to each element in the drawings. First Embodiment A primary configuration of a tape scale fixating device 100 is described with reference to FIGS. 1 to 4 . Points of the present disclosure are described thereafter. FIG. 1 is an exploded perspective view of the fixating device 100 of a tape scale 10 . FIG. 2 is an external view of an assembled state. The fixating device 100 of the tape scale 10 includes an elongated scale holder 110 , a fixing block part 120 arranged on a first end side of the scale holder 110 in a length direction, and a pulling block part 200 arranged on a second end side of the scale holder 110 in the length direction. The scale holder 110 , the fixing block part 120 , and the pulling block part 200 are formed mainly of metals such as aluminum, an aluminum alloy, or a SUS material. The scale holder 110 includes a groove into which the tape scale 10 fits. The fixing block part 120 is fixated to an object (not shown) by fixing screws 121 . Furthermore, the fixing block part 120 is screwed to a first end of the tape scale 10 by screws 122 . FIG. 3 is a cross-sectional view of the pulling block part 200 and FIG. 4 is an expanded view of a fixated base 210 and a slide part 240 . The pulling block part 200 includes the fixated base 210 , the slide part 240 , and a pulling screw (pulling mechanism or puller) 290 . The fixated base 210 is fixated to an object. The fixated base 210 includes a base portion 220 and a pulling wall 230 . The base portion 220 is long in a measurement axis direction and includes a groove 221 where the slide part 240 can slide along the length direction (measurement axis direction). The base portion 220 includes a slit 222 in the groove 221 , with a length from a first end partway toward a second end of the base portion 220 in the length direction. In addition, the base portion 220 includes four screw holes 223 and 224 along the length direction between substantially a center of the groove 221 and the second end. Of the four screw holes, the two on each end ( 223 ) are holes to screw the fixated base 210 to the object. The two in the middle ( 224 ) are holes for screwing in screws 253 , which press the slide part 240 provided inside the groove 221 of the fixated base 210 against the fixated base 210 . The pulling wall 230 is upright in an L-shape on the second end of the base portion 220 in the length direction (so as to be substantially perpendicular to the object when the base portion 220 is fixated to the object) and is a wall on the fixating side pulling the slide part 240 . Furthermore, the pulling wall 230 includes a hole 231 through which the pulling screw 290 passes. The slide part 240 includes a holding piece 250 and an end plate 260 . The holding piece 250 is arranged in the groove 221 of the base portion 220 and is slidable along the measurement axis direction. The second end of the tape scale 10 is screwed with screws ( 251 ) onto a top surface of a first end side of the holding piece 250 (an opposite surface to a surface facing the base portion 220 ), and the holding piece 250 holds the second end of the tape scale as a result. Moreover, a tip of each of the screws 251 enters the slit 222 of the base portion 220 such that the tape scale 10 is not fixated to the base portion 220 . When the slide part 240 slides with respect to the fixated base 210 , the tape scale 10 and the slide part 240 are integrally slidable with respect to the fixated base 210 . In addition, the holding piece 250 includes a elongated aperture 252 along the length direction between substantially the center and the second end. The elongated aperture 252 has a width through which threaded portions of the screws 253 can pass but head portions of the screws 253 cannot. Also, the threaded portions of the screws 253 are screwed into the screw holes 224 of the base portion 220 and the slide part 240 is pressed against the fixated base 210 by the head portions of the screws 253 while slide movement of the slide part 240 is allowed by the elongated aperture 252 . The end plate 260 is upright in an L-shape on the second end of the holding piece 250 and includes a screw hole 261 into which the pulling screw 290 is screwed. The pulling screw 290 is passed through the hole 231 of the pulling wall 230 and screwed into the screw hole 261 . As the pulling screw 290 is tightened, the end plate 260 is pulled toward the pulling wall 230 . By tightening the pulling screw 290 , a predetermined tension is applied to the tape scale 10 . In FIG. 3 , triangle marks show measurement points measured by an electric micrometer. A first electric micrometer ( 401 ) confirms that the fixated base 210 does not move. A second electric micrometer ( 402 ) monitors displacement of the slide part 240 . While watching a detection value from the second electric micrometer ( 402 ), the pulling screw 290 is tightened until an amount of displacement of the slide part 240 reaches the predetermined value. Next, a force applied to the slide part 240 is focused. The slide part 240 is pulled toward the second end side by the pulling screw 290 . This force is called “a second end side pulling force F 2 ” (see FIG. 3 ). In addition, the slide part 240 is pulled toward the first end side by the tape scale 10 . This force is called “a first end side pulling force F 1 ” (see FIG. 3 ). Furthermore, the slide part 240 is pressed against the fixated base 210 by the screws 253 inserted into the elongated aperture 252 of the holding piece 250 . Specifically, a friction force F 3 acts between a reverse surface of the holding piece 250 and a front surface of the base portion 220 (a bottom surface of the groove 221 ). When installed with tension applied to the tape scale 10 , the slide part 240 stays at a position with three forces in balance: the second end side pulling force F 2 , the first end side pulling force F 1 , and the friction force F 3 . (Of course, other forces are applied such as a friction force between the screws 253 and the holding piece 250 , but the three main forces are named to facilitate understanding.) The second end side pulling force F 2 and the first end side pulling force F 1 are considered to be unchanged over time. Instead, the present inventors focus on the friction force F 3 , which has been disregarded until now, and realize that the slide part 240 may be displaced by changes to the friction force F 3 . When environmental temperature is changed from 0° C. to 50° C. for example, the base portion 220 and the holding piece 250 are slightly thermally deformed and the friction force F 3 between the base portion 220 and the holding piece 250 changes. For example, the friction force F 3 may become smaller. Then, the balance between the second end side pulling force F 2 , the first end side pulling force F 1 , and the friction force F 3 changes, and therefore the balance position is displaced. Based on such findings, the present inventors have confirmed that there are three measures for effective solutions. A first measure is to prevent the friction force from changing even when there is a change in temperature. A second measure is to have no friction from the beginning. A third measure is to render the slide part 240 unmovable by generating an extremely large friction force. Descriptions are provided in that order. (1) Bevel Reverse Surface of Slide Part 240 . The slide part 240 is processed by cutting and therefore a burr may remain on an edge. When the burr remains, the burr comes in contact with the base portion 220 , and thus a contact area between the slide part 240 and the base portion 220 becomes extremely small. If there is a change in temperature and the like, the friction force F 3 changes and the slide part 240 may experience an unexpected slide. Therefore, the edge of the reverse surface of the slide part 240 is preferably beveled. As shown in FIG. 5 , the reverse surface of the slide part 240 has two projecting legs 270 on both sides in a width direction. Accordingly, an outer edge and an inner edge of each leg 270 are beveled ( 271 ). As a result, the slide part 240 and the base portion 220 come into surface-to-surface contact, and therefore the change of the friction force within a guaranteed temperature range becomes sufficiently small. Therefore, the slide part 240 is not displaced, or, even if displaced, the amount of displacement can be made sufficiently small. (2) Compensate for Variation in Components. The slide part 240 is pressed against the base portion 220 by pressing the screws 253 through the elongated aperture 252 of the holding piece 250 and screwing the screws 253 into the screw holes 224 of the base portion 220 . However, variations in a pressing force may be caused due to variations in components. For example, a length from a bearing surface to a tip of the screw 253 , roundness of a screw neck, and flatness of the bearing surface are likely to introduce variations. As a result, even if the screws 253 are tightened with the predetermined force, there is a possibility that the pressing force may be too strong or too weak. As shown in FIG. 6 , flanged sleeves 254 are mounted between the screws 253 and the elongated aperture 252 . As a result, variations in the components (the screws 253 and the slide part 240 ) are covered and the slide part 240 can be pressed against the base portion 220 with the predetermined pressing force every time when the screws 253 are tightened with the predetermined force. More preferably, when screwing the second end of the tape scale 10 to the holding piece 250 , flanged sleeves 255 are preferably mounted between the screws 251 and the tape scale 10 . When a diameter of holes 11 drilled in the tape scale 10 is larger than the diameter of the screws 251 , a gap is created between the hole 11 and the screw 251 . The gap can produce a margin in which the tape scale 10 relatively displaces with respect to the holding piece 250 . Therefore, it is better to mount the flanged sleeves 255 between the screws 251 and the tape scale 10 so as to eliminate the gap between the holes 11 and the screws 251 as much as possible and to firmly press the tape scale 10 with the screws 251 . Moreover, the tape scale 10 is thin such that sleeves of the flanged sleeves 255 need to be processed to be fairly short. If a thickness of the tape scale 10 is 0.2 mm, the length of the sleeve portion of the flanged sleeve 255 is processed to about 0.1 mm. When the length of the sleeve portion of the flanged sleeve 255 is to be several mm (about 1 mm, for example), the thickness of the first end side of the tape scale 10 can be slightly thicker or a shallow dent can be provided around a periphery of the screw holes 256 of the holding piece 250 . (3) Mirror Finish One Side Only. By mirror finishing one of the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 , the friction between the two becomes minimal, and is ideally zero. If there is no friction between the base portion 220 and the holding piece 250 from the beginning, the slide part 240 will not be displaced by a change in the friction force F 3 . A mirror surface may be defined as, for example, an arithmetic average roughness Ra of several tens of nm or less (such as 80 nm or less), and preferably 10 nm or less if possible. (4) Mirror Finish Both Sides. By mirror finishing both the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 , the friction between the two is extremely increased. The extremely large friction force is generated when both mirror-finished metals (such as aluminum) come in close contact. As a result, the slide part 240 is not displaced by a change in the friction force F 3 . The mirror surface may be defined as, for example, the arithmetic average roughness Ra of several tens of nm or less (such as 80 nm or less), and preferably 10 nm or less if possible. Results of Assessment FIG. 7 shows results of an assessment. FIG. 7 shows results of measuring the displacement of the slide part 240 with the second electric micrometer ( 402 ) after tightening the pulling screw 290 until an amount of pulling of the slide part 240 reaches the predetermined value. (A positive value indicates displacement to the first end side.) The length of the tape scale is 1 m. A line at a pulling force at 600 N is shown in the drawing. 600 N corresponds to the pulling force which can absorb an amount of expansion/contraction at a temperature change of 40° C. Line (A) in the drawing shows the result when the slide part 240 is not beveled. Line ( 1 ) in the drawing shows the result when the slide part 240 is beveled. Line ( 2 ) in the drawing shows the result when the slide part 240 is beveled and further mounted with the flanged sleeves 254 between the screws 253 and the elongated aperture 252 . Line ( 3 ) in the drawing shows the result when the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 are mirror finished. Based on the results in FIG. 7 , the measures mentioned above show positive results. (5) One Rough Surface and Other Surface Covered in Resin Film. When a first member has a rough surface and a second member is covered in a resin film, the first member holds on to the second. As shown in FIG. 8 , for example, the bottom surface of the groove 221 of the base portion 220 is configured to be rough and the reverse surface of the holding piece 250 is covered with a thin film 272 of resin, for example. Naturally, the reverse surface of the holding piece 250 may instead be configured to be rough and the bottom surface of the groove 221 of the base portion 220 may be covered in the resin film. As a result, the friction force between the two is maintained, preventing the displacement of the slide part 240 . A rough surface may be defined as, for example, the arithmetic average roughness Ra of between several tenths of a μm and several tens of μm, with between 0.1 μm and 50 μm given as an example. Moreover, the present invention is not limited to the embodiments described above, and may be modified as needed without departing from the scope of the present invention. For example, so long as the slide part is pulled relatively to the second end side with respect to the fixated base, the pulling screw can be replaced by an elastic body such as a spring. The shapes of the fixated base and the slide part are merely examples. It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular structures, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. The present invention is not limited to the above described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention.
A scale fixating device includes a fixing block unmovably fixating a first end of a scale to an object, and a pulling block fixating a second end of the scale to the object while pulling the second end of the scale to the second end side. The pulling block includes a fixated base fixated to an object, a slide holding the second end of the scale and installed slidably with respect to the fixated base, and a pulling mechanism having a first end engaged to the slide and a second end engaged to the fixated base, the pulling mechanism pulling the slide toward the second end relatively with respect to the fixated base. The scale fixating device either prevents a friction force from changing between the slide and the fixated base or generates an extremely large friction force between the slide and the fixated base.
Condense the core contents of the given document.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority under 35 U.S.C. §119 of Japanese Application No. 2014-266856, filed on Dec. 27, 2014, and Japanese Application No. 2015-140317, filed on Jul. 14, 2015, the disclosures of which are expressly incorporated by reference herein in their entirety.", "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to a scale fixating device.", "Specifically, the present invention relates to a device for fixating a scale enabling accuracy of a scale to be maintained when mounting and fixating an elongated scale to an object.", "Description of Related Art As a scale in an instrument measuring length (linear encoder), a tape scale formed in a thin tape shape made of glass or a metal is known.", "(Japanese Patent Laid-open Publication No. 2011-237310, Japanese Patent No. 4,477,442, Japanese Patent Laid-open Publication No. 2013-7718, and Japanese Patent Laid-open Publication No. S63-252213.) The tape scale provides advantages such as easy lengthening, easy transportation, and simple mounting.", "When a tape scale is mounted and fixated to an object, tension is applied in a measurement axis direction.", "For example, a first end of the tape scale is unmovably fixated to the object and a second end of the tape scale is fixated to a sliding member allowing the second end of the tape scale to move relative to the object.", "In addition, the tension is applied to the sliding member so as to pull the second end of the tape scale.", "As a result, even in a case where the tape scale is expanded/contracted by a change in temperature, the tape scale maintains straightness.", "Generally, a guarantee temperature is set from 0° C. to 50° C. and the tension is applied such that the straightness is maintained within this range.", "For example, when the tape scale is made of a SUS material, there is about 10.5 μm expansion/contraction per 1 meter with a change in temperature of 1° C. In order to absorb the expansion/contraction, when the encoder is installed at a temperature of 20° C., a pull of 250 μm per 1 meter is required.", "As described above, the predetermined tension is applied to the tape scale via the sliding member, however, when inspected after some time following the encoder installation, the tension is often changed.", "In other words, the sliding member is pulled by the predetermined amount (250 μm per 1 meter), however, a position of the sliding member is displaced from an initial installed position when inspected after some time.", "A user of the encoder does not check if the tension of the tape scale is appropriate or not once the encoder is installed, which may lead to a measurement error.", "Displacement does not occur in all cases and although a cause was unknown, was thought to be a difference in ability during encoder installation.", "The present inventors have carried out extensive studies and succeeded in shedding light on a fundamental cause, as well as devising a countermeasure to achieve the present disclosure.", "SUMMARY OF THE INVENTION An advantage of the present disclosure is to provide a scale fixating device capable of maintaining accuracy of a scale while preventing tension of the scale from changing.", "The scale fixating device according to the present disclosure installs and fixates the scale to an object and includes a fixing block part unmovably fixating a first end of the scale to the object and a pulling block part fixating a second end of the scale to an object while pulling the second end of the scale.", "The pulling block part includes a fixated base fixated to the object, a slide part holding the second end of the scale and installed slidably with respect to the fixated base, and a pulling mechanism (also referred to as a “puller”) having a first end engaged to the slide part and a second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base.", "A surface of the slide part contacting the fixated base is beveled.", "The scale fixating device according to the present disclosure installs and fixates the scale to the object and includes the fixing block part unmovably fixating the first end of the scale to the object and the pulling block part fixating the second end of the scale to the object while pulling the second end of the scale.", "The pulling block part includes the fixated base fixated to the object, the slide part holding the second end of the scale and installed slidably with respect to the fixated base, and the pulling mechanism having the first end engaged to the slide part and the second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base.", "At least one of a mutual contact surface of the slide part and a mutual contact surface of the fixated base is mirror finished.", "The scale fixating device according to the present disclosure installs and fixates the scale to the object and includes the fixing block part unmovably fixating the first end of the scale to the object and the pulling block part fixating the second end of the scale to the object while pulling the second end of the scale.", "The pulling block part includes the fixated base fixated to the object, the slide part holding the second end of the scale and installed slidably with respect to the fixated base, and the pulling mechanism having the first end engaged to the slide part and the second end engaged to the fixated base, the pulling mechanism pulling the slide part toward the second end relatively with respect to the fixated base.", "One of the mutual contact surface of the slide part and the mutual contact surface of the fixated base has a rough surface while the other is covered in a resin film.", "In the present disclosure, the slide part includes a elongated aperture and is pressed against the fixated base with a first screw inserted through the elongated aperture and screwed to the fixated base, and a first flanged sleeve is preferably mounted between the first screw and the elongated aperture.", "In the present disclosure, the second end of the scale is screwed to the slide part with a second screw and a second flanged sleeve is preferably installed between the second screw and the second end of the scale.", "BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present disclosure, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein: FIG. 1 is an exploded perspective view of a tape scale fixating device;", "FIG. 2 is an external view of the tape scale fixating device;", "FIG. 3 is a cross-sectional view of a pulling block part;", "FIG. 4 is an expanded view of a fixated base and a slide part;", "FIG. 5 illustrates a beveled slide part;", "FIG. 6 illustrates a flanged sleeve;", "FIG. 7 illustrates assessment results;", "and FIG. 8 illustrates a case where a base portion has a rough surface and a thin film is formed on a holding piece.", "DETAILED DESCRIPTION OF THE INVENTION The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention.", "In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the forms of the present invention may be embodied in practice.", "An embodiment of the present disclosure is shown and described with reference to numerals given to each element in the drawings.", "First Embodiment A primary configuration of a tape scale fixating device 100 is described with reference to FIGS. 1 to 4 .", "Points of the present disclosure are described thereafter.", "FIG. 1 is an exploded perspective view of the fixating device 100 of a tape scale 10 .", "FIG. 2 is an external view of an assembled state.", "The fixating device 100 of the tape scale 10 includes an elongated scale holder 110 , a fixing block part 120 arranged on a first end side of the scale holder 110 in a length direction, and a pulling block part 200 arranged on a second end side of the scale holder 110 in the length direction.", "The scale holder 110 , the fixing block part 120 , and the pulling block part 200 are formed mainly of metals such as aluminum, an aluminum alloy, or a SUS material.", "The scale holder 110 includes a groove into which the tape scale 10 fits.", "The fixing block part 120 is fixated to an object (not shown) by fixing screws 121 .", "Furthermore, the fixing block part 120 is screwed to a first end of the tape scale 10 by screws 122 .", "FIG. 3 is a cross-sectional view of the pulling block part 200 and FIG. 4 is an expanded view of a fixated base 210 and a slide part 240 .", "The pulling block part 200 includes the fixated base 210 , the slide part 240 , and a pulling screw (pulling mechanism or puller) 290 .", "The fixated base 210 is fixated to an object.", "The fixated base 210 includes a base portion 220 and a pulling wall 230 .", "The base portion 220 is long in a measurement axis direction and includes a groove 221 where the slide part 240 can slide along the length direction (measurement axis direction).", "The base portion 220 includes a slit 222 in the groove 221 , with a length from a first end partway toward a second end of the base portion 220 in the length direction.", "In addition, the base portion 220 includes four screw holes 223 and 224 along the length direction between substantially a center of the groove 221 and the second end.", "Of the four screw holes, the two on each end ( 223 ) are holes to screw the fixated base 210 to the object.", "The two in the middle ( 224 ) are holes for screwing in screws 253 , which press the slide part 240 provided inside the groove 221 of the fixated base 210 against the fixated base 210 .", "The pulling wall 230 is upright in an L-shape on the second end of the base portion 220 in the length direction (so as to be substantially perpendicular to the object when the base portion 220 is fixated to the object) and is a wall on the fixating side pulling the slide part 240 .", "Furthermore, the pulling wall 230 includes a hole 231 through which the pulling screw 290 passes.", "The slide part 240 includes a holding piece 250 and an end plate 260 .", "The holding piece 250 is arranged in the groove 221 of the base portion 220 and is slidable along the measurement axis direction.", "The second end of the tape scale 10 is screwed with screws ( 251 ) onto a top surface of a first end side of the holding piece 250 (an opposite surface to a surface facing the base portion 220 ), and the holding piece 250 holds the second end of the tape scale as a result.", "Moreover, a tip of each of the screws 251 enters the slit 222 of the base portion 220 such that the tape scale 10 is not fixated to the base portion 220 .", "When the slide part 240 slides with respect to the fixated base 210 , the tape scale 10 and the slide part 240 are integrally slidable with respect to the fixated base 210 .", "In addition, the holding piece 250 includes a elongated aperture 252 along the length direction between substantially the center and the second end.", "The elongated aperture 252 has a width through which threaded portions of the screws 253 can pass but head portions of the screws 253 cannot.", "Also, the threaded portions of the screws 253 are screwed into the screw holes 224 of the base portion 220 and the slide part 240 is pressed against the fixated base 210 by the head portions of the screws 253 while slide movement of the slide part 240 is allowed by the elongated aperture 252 .", "The end plate 260 is upright in an L-shape on the second end of the holding piece 250 and includes a screw hole 261 into which the pulling screw 290 is screwed.", "The pulling screw 290 is passed through the hole 231 of the pulling wall 230 and screwed into the screw hole 261 .", "As the pulling screw 290 is tightened, the end plate 260 is pulled toward the pulling wall 230 .", "By tightening the pulling screw 290 , a predetermined tension is applied to the tape scale 10 .", "In FIG. 3 , triangle marks show measurement points measured by an electric micrometer.", "A first electric micrometer ( 401 ) confirms that the fixated base 210 does not move.", "A second electric micrometer ( 402 ) monitors displacement of the slide part 240 .", "While watching a detection value from the second electric micrometer ( 402 ), the pulling screw 290 is tightened until an amount of displacement of the slide part 240 reaches the predetermined value.", "Next, a force applied to the slide part 240 is focused.", "The slide part 240 is pulled toward the second end side by the pulling screw 290 .", "This force is called “a second end side pulling force F 2 ”", "(see FIG. 3 ).", "In addition, the slide part 240 is pulled toward the first end side by the tape scale 10 .", "This force is called “a first end side pulling force F 1 ”", "(see FIG. 3 ).", "Furthermore, the slide part 240 is pressed against the fixated base 210 by the screws 253 inserted into the elongated aperture 252 of the holding piece 250 .", "Specifically, a friction force F 3 acts between a reverse surface of the holding piece 250 and a front surface of the base portion 220 (a bottom surface of the groove 221 ).", "When installed with tension applied to the tape scale 10 , the slide part 240 stays at a position with three forces in balance: the second end side pulling force F 2 , the first end side pulling force F 1 , and the friction force F 3 .", "(Of course, other forces are applied such as a friction force between the screws 253 and the holding piece 250 , but the three main forces are named to facilitate understanding.) The second end side pulling force F 2 and the first end side pulling force F 1 are considered to be unchanged over time.", "Instead, the present inventors focus on the friction force F 3 , which has been disregarded until now, and realize that the slide part 240 may be displaced by changes to the friction force F 3 .", "When environmental temperature is changed from 0° C. to 50° C. for example, the base portion 220 and the holding piece 250 are slightly thermally deformed and the friction force F 3 between the base portion 220 and the holding piece 250 changes.", "For example, the friction force F 3 may become smaller.", "Then, the balance between the second end side pulling force F 2 , the first end side pulling force F 1 , and the friction force F 3 changes, and therefore the balance position is displaced.", "Based on such findings, the present inventors have confirmed that there are three measures for effective solutions.", "A first measure is to prevent the friction force from changing even when there is a change in temperature.", "A second measure is to have no friction from the beginning.", "A third measure is to render the slide part 240 unmovable by generating an extremely large friction force.", "Descriptions are provided in that order.", "(1) Bevel Reverse Surface of Slide Part 240 .", "The slide part 240 is processed by cutting and therefore a burr may remain on an edge.", "When the burr remains, the burr comes in contact with the base portion 220 , and thus a contact area between the slide part 240 and the base portion 220 becomes extremely small.", "If there is a change in temperature and the like, the friction force F 3 changes and the slide part 240 may experience an unexpected slide.", "Therefore, the edge of the reverse surface of the slide part 240 is preferably beveled.", "As shown in FIG. 5 , the reverse surface of the slide part 240 has two projecting legs 270 on both sides in a width direction.", "Accordingly, an outer edge and an inner edge of each leg 270 are beveled ( 271 ).", "As a result, the slide part 240 and the base portion 220 come into surface-to-surface contact, and therefore the change of the friction force within a guaranteed temperature range becomes sufficiently small.", "Therefore, the slide part 240 is not displaced, or, even if displaced, the amount of displacement can be made sufficiently small.", "(2) Compensate for Variation in Components.", "The slide part 240 is pressed against the base portion 220 by pressing the screws 253 through the elongated aperture 252 of the holding piece 250 and screwing the screws 253 into the screw holes 224 of the base portion 220 .", "However, variations in a pressing force may be caused due to variations in components.", "For example, a length from a bearing surface to a tip of the screw 253 , roundness of a screw neck, and flatness of the bearing surface are likely to introduce variations.", "As a result, even if the screws 253 are tightened with the predetermined force, there is a possibility that the pressing force may be too strong or too weak.", "As shown in FIG. 6 , flanged sleeves 254 are mounted between the screws 253 and the elongated aperture 252 .", "As a result, variations in the components (the screws 253 and the slide part 240 ) are covered and the slide part 240 can be pressed against the base portion 220 with the predetermined pressing force every time when the screws 253 are tightened with the predetermined force.", "More preferably, when screwing the second end of the tape scale 10 to the holding piece 250 , flanged sleeves 255 are preferably mounted between the screws 251 and the tape scale 10 .", "When a diameter of holes 11 drilled in the tape scale 10 is larger than the diameter of the screws 251 , a gap is created between the hole 11 and the screw 251 .", "The gap can produce a margin in which the tape scale 10 relatively displaces with respect to the holding piece 250 .", "Therefore, it is better to mount the flanged sleeves 255 between the screws 251 and the tape scale 10 so as to eliminate the gap between the holes 11 and the screws 251 as much as possible and to firmly press the tape scale 10 with the screws 251 .", "Moreover, the tape scale 10 is thin such that sleeves of the flanged sleeves 255 need to be processed to be fairly short.", "If a thickness of the tape scale 10 is 0.2 mm, the length of the sleeve portion of the flanged sleeve 255 is processed to about 0.1 mm.", "When the length of the sleeve portion of the flanged sleeve 255 is to be several mm (about 1 mm, for example), the thickness of the first end side of the tape scale 10 can be slightly thicker or a shallow dent can be provided around a periphery of the screw holes 256 of the holding piece 250 .", "(3) Mirror Finish One Side Only.", "By mirror finishing one of the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 , the friction between the two becomes minimal, and is ideally zero.", "If there is no friction between the base portion 220 and the holding piece 250 from the beginning, the slide part 240 will not be displaced by a change in the friction force F 3 .", "A mirror surface may be defined as, for example, an arithmetic average roughness Ra of several tens of nm or less (such as 80 nm or less), and preferably 10 nm or less if possible.", "(4) Mirror Finish Both Sides.", "By mirror finishing both the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 , the friction between the two is extremely increased.", "The extremely large friction force is generated when both mirror-finished metals (such as aluminum) come in close contact.", "As a result, the slide part 240 is not displaced by a change in the friction force F 3 .", "The mirror surface may be defined as, for example, the arithmetic average roughness Ra of several tens of nm or less (such as 80 nm or less), and preferably 10 nm or less if possible.", "Results of Assessment FIG. 7 shows results of an assessment.", "FIG. 7 shows results of measuring the displacement of the slide part 240 with the second electric micrometer ( 402 ) after tightening the pulling screw 290 until an amount of pulling of the slide part 240 reaches the predetermined value.", "(A positive value indicates displacement to the first end side.) The length of the tape scale is 1 m. A line at a pulling force at 600 N is shown in the drawing.", "600 N corresponds to the pulling force which can absorb an amount of expansion/contraction at a temperature change of 40° C. Line (A) in the drawing shows the result when the slide part 240 is not beveled.", "Line ( 1 ) in the drawing shows the result when the slide part 240 is beveled.", "Line ( 2 ) in the drawing shows the result when the slide part 240 is beveled and further mounted with the flanged sleeves 254 between the screws 253 and the elongated aperture 252 .", "Line ( 3 ) in the drawing shows the result when the bottom surface of the groove 221 of the base portion 220 and the reverse surface of the holding piece 250 are mirror finished.", "Based on the results in FIG. 7 , the measures mentioned above show positive results.", "(5) One Rough Surface and Other Surface Covered in Resin Film.", "When a first member has a rough surface and a second member is covered in a resin film, the first member holds on to the second.", "As shown in FIG. 8 , for example, the bottom surface of the groove 221 of the base portion 220 is configured to be rough and the reverse surface of the holding piece 250 is covered with a thin film 272 of resin, for example.", "Naturally, the reverse surface of the holding piece 250 may instead be configured to be rough and the bottom surface of the groove 221 of the base portion 220 may be covered in the resin film.", "As a result, the friction force between the two is maintained, preventing the displacement of the slide part 240 .", "A rough surface may be defined as, for example, the arithmetic average roughness Ra of between several tenths of a μm and several tens of μm, with between 0.1 μm and 50 μm given as an example.", "Moreover, the present invention is not limited to the embodiments described above, and may be modified as needed without departing from the scope of the present invention.", "For example, so long as the slide part is pulled relatively to the second end side with respect to the fixated base, the pulling screw can be replaced by an elastic body such as a spring.", "The shapes of the fixated base and the slide part are merely examples.", "It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention.", "While the present invention has been described with reference to exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation.", "Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects.", "Although the present invention has been described herein with reference to particular structures, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein;", "rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.", "The present invention is not limited to the above described embodiments, and various variations and modifications may be possible without departing from the scope of the present invention." ]
TECHNICAL BACKGROUND [0001] The present invention regards protecting a coated work-piece during its manufacture or reconfiguration. More specifically the present invention regards reducing the probability of damaging the coating of a work-piece during the work-piece's manufacture by managing or regulating the temperature of the coating. BACKGROUND OF THE INVENTION [0002] Articles of manufacture are regularly coated for numerous and varying reasons. For example, they may be coated to protect them from the intrusive handling they may be subjected to during their manufacture or to protect them from the environmental effects they may endure after they are manufactured. In either of these, as well as in others, damage to the coating of a work-piece, resulting from the handling or reconfiguration of the work-piece, is an unwanted result. [0003] When the coating of a work-piece becomes scratched or otherwise damaged during the work-piece's manufacture, the scratches can promote the deterioration of the work-piece by exposing the work-piece's surface to its surroundings. Should the work-piece, upon its completion, be employed in a corrosive environment, the exposed surface of the finished product would be more vulnerable to corrosion than if its coating were completely intact. Moreover, the scratches and inconsistencies in the coating of the work-piece may also reduce the effectiveness of the finished product. For example, should the coating be used to uniformly deliver some type of releasable substance, inconsistencies in the surface of the coating can foster uneven and inconsistent delivery of the releasable substance to the deployed product's final surroundings. [0004] An expandable coated stent is one specific example of the coated work-pieces described above. Expandable stents are tube-like medical devices designed to support the inner walls of a vessel within the body of a patient. These stents are typically positioned within a targeted lumen of the body and then expanded to provide internal support for the lumen. These stents may be self-expanding or, alternatively, may require external forces to expand them. In either case they are typically deployed through the use of a catheter of some kind. These catheters typically carry the stent at their distal ends. In use, a practitioner will position the catheter's distal end near the target area of the lumen. Once properly positioned the stent will be deployed by the practitioner such that it comes to rest near or in direct contact with the inner walls of the lumen. There, the stent will remain to provide support for the lumen. [0005] Due to the interaction of the stent with the inner walls of the lumen, stents have been coated to enhance their effectiveness. These coatings may, among other things, be designed to facilitate the acceptance of the stent into its applied surroundings or to enable the delivery of therapeutic to the lumen and its surroundings. Thus, when the coating is haphazardly applied or has somehow been removed during the stent's manufacture, both the stent's longevity and its effectiveness can be reduced. [0006] The coatings on the stent may be applied at various times during its life cycle including its manufacture, its placement onto the distal end of the delivery catheter, and contemporaneous with the medical procedure. At each of these times the coating may be at risk of being scratched, damaged or otherwise removed from the surface of the stent. For example, during their manufacture, stents are often crimped onto the distal end of a delivery catheter. This crimping process requires the exertion of significant forces against the coating of the stent to facilitate a reduction in the stent's circumference to secure it to the catheter. During this crimping, the mechanical arms of a crimper may come in contact with the coating of the stent as they reduce the diameter of the stent. This compressive contact can scratch, indent, wipe-off or otherwise breach the integrity of the coating—an undesirable result. SUMMARY OF THE INVENTION [0007] Thermal regulation of a coated work-piece during the reconfiguration of the work-piece is provided. One method embodying the invention comprises placing an externally coated reconfigurable work-piece, whose hardness has been temporarily modified to resist damage during the reconfiguration of the work-piece, into a reconfiguration chamber of a reconfiguration apparatus and reconfiguring the work-piece from a first configuration to a second configuration via physical communication between the external coating of the reconfigurable work-piece and the reconfiguration apparatus. [0008] An apparatus embodying the invention includes a reconfiguration chamber, a nozzle in fluid communication with the reconfiguration chamber, a regulator in fluid communication with the nozzle, the regulator adapted to regulate the flow of a thermal transfer fluid, and a controller in communication with the regulator. Wherein the controller is adapted to send control signals to the regulator to maintain the surface temperature of the external coating of the reconfigurable work-piece within a predetermined temperature range and wherein the predetermined temperature range affords a predetermined minimum hardness for the external coating of the reconfigurable work-piece. BRIEF DESCRIPTION OF THE DRAWINGS [0009] [0009]FIG. 1 is a graph of volume versus temperature for an exemplary polymer coating. [0010] [0010]FIG. 2 is an enlarged partial side cross-sectional view of a reconfiguration chamber and a reconfigurable coated work-piece prior to the reconfiguration of the coated work-piece in accord with an embodiment of the present invention. [0011] [0011]FIG. 3 is the view of FIG. 2 shown during the reconfiguration of the coated work-piece in accord with an embodiment of the present invention. [0012] [0012]FIG. 4 is a cross-sectional view of a reconfiguration chamber shown prior to the execution of a work stroke in accord with an alternative embodiment of the present invention. [0013] [0013]FIG. 5 is a sectional view taken along line 5 - 5 of FIG. 4. [0014] [0014]FIG. 6 is another cross-sectional view of the reconfiguration chamber of FIG. 4 shown after a work stroke has been completed in accord with an alternative embodiment of the present invention. [0015] [0015]FIG. 7 is a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention. [0016] [0016]FIG. 8 is a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention. [0017] [0017]FIG. 9 is a side view of a self-expanding stent within a sheath as manufactured by a method in accord with another alternative embodiment of the present invention. [0018] [0018]FIG. 10 is an enlarged side cross-sectional view of a reconfiguration chamber in accord with another alternative embodiment of the present invention. [0019] [0019]FIG. 11 is an enlarged side cross-sectional view of a reconfiguration chamber in accord with another alternative embodiment of the present invention. DETAILED DESCRIPTION [0020] In one embodiment of the present invention the hardness or resilience of the coating of a work-piece is temporarily increased by adjusting its preexisting temperature to be closer to its glass transition temperature. Then, while the coating is in this temporarily hardened or more resilient state, the force required to reconfigure the work-piece is applied against the coating. By temporarily increasing the hardness of the coating through its change in temperature, the coating is better able to withstand the forces and pressures exerted upon it during the reconfiguration of the work-piece. Thus, the coating is more likely to remain intact both during the remainder of the manufacturing of the work-piece and after the work-piece has been completely manufactured and is employed for its intended purpose. [0021] [0021]FIG. 1 is a graph of volume versus temperature for a polymer that may be used as a coating in accord with one embodiment of the present invention. The temperature of the polymer is plotted along the x-axis 11 while its corresponding volume is plotted along the y-axis 10 . The glass transition temperature (T g ) 12 as well as the melting temperature (T m ) 13 are specifically labeled on the x-axis 11 of the graph. Also labeled in the graph is the line 18 representing the specific volume for a given temperature of this exemplary polymer. This line 18 has three phase ranges identified on it, the glass phase 14 , the super-cooled liquid phase 15 , and the liquid phase 16 . The crystalline property delineation line 17 for this exemplary polymer is also evident in FIG. 1. [0022] The exemplary polymer graphed in FIG. 1 is a typical polymer. It is comprised of chains or strings of molecules that are interwoven and able to move in and around one another. As the polymer cools the chains loose their ability to freely flow around and among one another, and, thus, the polymer becomes stiffer and decreases in volume. [0023] When the polymer temperature is within the liquid range 16 the chains of molecules comprising the polymer may move freely amongst one another and, consequently, the polymer behaves much like a liquid. As the temperature decreases, the thermal agitation among the molecules lessens and the volume of the liquid shrinks. This decrease in volume continues below the melting point (T m ) 13 of the polymer and into its super-cooled liquid range. Below the melting point (T m ) 13 , the chains of molecules may still flow around and among themselves but they do so at a lower rate than in the liquid phase. It is here, in this super-cooled liquid range, that the hardness and resiliency of the polymer will increase as its temperature approaches the glass transition temperature (T g ) 12 . When the temperature of the polymer reaches the glass transition temperature (T g ) 12 the polymer enters the glass phase 14 . Here, the polymer becomes more brittle than in the super-cooled liquid phase as the molecules can no longer continually rearrange themselves. Moreover, as is evident in the graph of FIG. 1, the rate of volume change in relation to temperature changes at this point as it is one constant above the glass transition temperature (T g ) 12 and a different constant below the glass transition temperature (T g ) 12 . [0024] [0024]FIG. 2 provides an enlarged partial cross-section of a slidable outer wall 20 of a reconfiguration chamber positioned near a reconfigurable work-piece 22 , prior to a work stroke, in accord with one embodiment of the present invention. In this embodiment, prior to the beginning of a work stroke, the slidable outer wall is not in contact with the coating 21 or the reconfigurable work-piece 22 as is evident by the existence of void 23 . [0025] [0025]FIG. 3 provides an enlarged cross-section of the slidable outer wall 20 and the reconfigurable work-piece 22 of FIG. 2 during a work stroke. As can be seen, the slidable outer wall 20 is in direct contact with the coating 21 of the reconfigurable work-piece 22 . As is also evident, most but not all of the void 23 is filled during the work stroke as some small areas of void 23 remain when the slidable outer wall 22 comes in contact with the coating. [0026] In order to increase the resiliency and hardness of the coating and to reduce the potential damage to it from the direct contact with the slidable outer wall 20 , the coating may be cooled to be within its super-cooled liquid range. By lowering the temperature of the coating 21 , closer to the glass transition temperature of the coating, the coating 21 can be sufficiently hardened to protect it from the forces generated by its direct contact with the slidable outer wall 20 . Due to this temporal hardening, the coating 21 may remain substantially intact on the work-piece and may be able to continue to protect the work-piece 22 during the remaining steps of its manufacture and, afterwards, as the work-piece is deployed for its intended use. [0027] The slidable outer wall 20 provided in FIGS. 2 - 3 may be any one of innumerable pinching, moving, or force exerting components of a manufacturing machine or process. Likewise, the reconfigurable work-piece may be any one of innumerable work-pieces or products of manufacture currently manufactured in modem manufacturing systems. In addition, the coating 21 may be one of numerous commercial or industrial coatings including various ceramics, polymers, and waxes. These polymers could include SIBS polymers (styrene-isobutylene-styrene) and any other suitable polymer. [0028] [0028]FIG. 4 is a cross-sectional view of a reconfiguration chamber 40 as may be used to crimp or crease a stent 42 onto the distal end of a balloon catheter 44 in accordance with an alternative embodiment of the present invention. As can be seen in FIG. 4, the reconfiguration chamber 40 has slidable outer walls 41 that are in physical communication with one another and define a hexagonal-like adjustable aperture. Resident within this aperture is the distal end of a balloon catheter 44 having an exterior wall 45 . A stent 42 , encircling the distal end of the balloon catheter 44 and having a coating 47 with an exterior surface of the coating 48 , is also pictured in FIG. 4. As can also be seen in this embodiment, the exterior surface of the coating 48 has a void 43 between it and the interior faces of the slidable outer walls 41 . This void 43 may exist both before and after the completion of a work stroke of the slidable outer walls 41 . The initial diameter of the stent 42 , prior to the completion of a work stroke, is indicated with the character d 1 and the numeral 49 . [0029] In this embodiment, the slidable outer walls 41 of the reconfiguration chamber 40 are activated to crimp the stent 42 onto the balloon catheter 44 . When activated, the slidable outer walls 41 slide towards one another and, thus, reduce the size of the aperture defined by them. As the aperture's diameter reaches the size of the exterior surface 48 of the coating 47 , pressure is begun to be exerted on the coating 47 of the stent 42 and the stent begins to be reconfigured. As the diameter of the aperture is further reduced so too is the cross-sectional diameter of the stent 42 . In order to retard damage to the coating 47 that contacts the slidable outer walls 41 , the temperature of the coating 47 has been adjusted either before placing the stent 42 into the reconfiguration chamber 40 or while the stent 42 is located within the reconfiguration chamber 40 . [0030] In this embodiment the temperature of the coating 47 is adjusted after the stent has been placed within the reconfiguration chamber 40 . Here, a thermally conductive fluid may be flushed through the void 43 and in contact with the coating 47 to adjust the coating's temperature. Dependant upon the ambient temperature, the coating's preexisting temperature, and the glass transition temperature of the coating, the temperature of the existing surface of the coating 47 may be either heated or cooled. In this embodiment the temperature of the coating is reduced through the introduction of cooled ultra-dry air into the void 43 until the desired resultant temperature of the coating 47 is achieved. Other cooling mediums may also be used including both compressible and non-compressible fluids. The desired resultant temperature may depend upon the glass transition temperature of the coating, the structural rigidity of the stent, the properties of the balloon catheter, and the anticipated future handling of the stent. The desired temperature or temperature range may be a percentage of the T g or it may be a specific range of quantified values. In this embodiment, the desired temperature range is approximately 20° Celsius above the glass transition temperature of the coating. [0031] In this embodiment, once the temperature of the coating has been adjusted to be within the desired temperature range, the slidable outer walls 41 may complete a work stroke by sliding inwardly and, consequently, reconfiguring the stent 42 from a first position having a diameter d 1 to a second position having a diameter d 2 (illustrated in FIG. 6). [0032] An insulating tube 46 is positioned around the slidable outer walls 41 and is clearly evident in FIG. 4. This insulating tube 46 provides additional thermal buffering between the potentially extreme temperatures generated within the reconfiguration chamber and its surroundings. The insulating tube 46 may be made from an insulating ceramic or any other suitable insulating material. The slidable outer walls 41 may also be designed to provide buffering between the extreme temperatures generated within the reconfiguration chamber and the surroundings. For example the slidable outer walls 41 may be made from materials such as Dupont™ Delrin™ (acetal homopolymer and copolymer) and Zirconium oxide ceramic which has been partially stabilized with Yttria to provide supplementary thermal buffering between the work-piece and the surrounding area. [0033] [0033]FIG. 5 is a side cross-sectional view taken along line 5 - 5 of the reconfiguration chamber 40 of FIG. 4. Various features of the reconfiguration tube 40 are evident in this illustration including the entrance tube 51 , the exit tube 53 , nozzles 52 and 54 , insulating tube 46 , coating 47 , thermal transfer fluid flow arrows 50 , thermal transfer fluid 55 , stent 42 , slidable outer walls 41 , balloon catheter exterior surface 45 , balloon catheter 44 , regulator 56 , and controller 57 . [0034] After the distal end of the catheter 44 has been placed within the reconfiguration chamber 40 , in order to adjust the temperature of the coating 47 , thermal transfer fluid 53 may be delivered through tube 51 and nozzle 52 into direct contact with the coating 47 . Then, after passing over the coated stent, the fluid 50 may be recaptured through nozzles 54 and exit tubes 53 where it can be stored or recycled back into the process. The thermal transfer fluid 55 may be introduced and circulated both prior to and during the reconfiguration of the stent 42 , although it is preferable that the flow of the thermal transfer fluid 55 be halted once the slidable outer walls 41 have begun to move. The thermal transfer fluid may be any one of numerous suitable fluids, including liquid nitrogen, water, liquid helium, dry air, nitrogen, helium, or any other suitable compressible and non-compressible fluids. [0035] After the crimping has occurred the slidable outer wall 41 may open and the thermal transfer fluid 55 may cease its flow through the chamber. The balloon catheter 44 may then be removed from the reconfiguration chamber 40 and its temperature permitted to return to the ambient temperature. Alternatively, the distal end of the catheter 44 , carrying the now crimped stent 42 , may be subjected to other manufacturing steps that may also benefit from the coating's temporally increased hardness. [0036] In this embodiment the regulator 56 and controller 57 act together as a means for adjusting and maintaining the temperature of the coating 58 although other configurations for this means are plausible. These components work together to adjust and maintain the temperature of the coating 47 . The amount of fluid flowing through the entrance nozzles 52 into the reconfiguration chamber may be monitored by the controller 57 . When the requisite flow is detected no action may be required. However, should the controller 57 determine that the rate of fluid flow should be adjusted, in order to adjust or maintain the temperature of the coating 47 , it may, as required, send a signal that opens or closes the regulator 56 . [0037] This means for adjusting and maintaining the temperature 58 can take numerous other configurations. For example, while it is illustrated as being comprised of regulators and controllers regulating the flow of fluid into the reconfiguration chamber, this means could, instead, comprise manually adjustable valves that are adjusted by an operator monitoring the temperature of the coating. Alternatively, this means could also be electrical coils or hollow thermal conduction tubes carrying a thermal conductive fluid such as liquid nitrogen. The coils in either case may be placed within the slidable outer walls 41 and may be used to provide the thermal adjustment of the coating of the stent via the regulation of the fluid or electrical current flowing through them. [0038] [0038]FIG. 6 provides an enlarged cross-sectional view of the reconfiguration chamber during a work stroke. As can be seen in FIG. 6 the slidable outer walls 41 , containing residual transfer fluid 55 in the voids 43 , have closed in on themselves and have reconfigured the stent 42 into a second position such that the diameter d 2 of the stent 42 is smaller than the diameter d 1 of the stent 42 in FIG. 4. Because the temperature of the coating was brought closer to its glass transition temperature, the coating has substantially retained its shape, has not been substantially damaged, and has adequately transferred the forces generated from the slidable outer walls to the stent 42 . [0039] [0039]FIG. 7 shows a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention. In FIG. 7, nozzle 74 , catheter 79 , stent 76 , flow arrow 77 , thermocouple 78 , slidable outer walls 75 , uptake 72 , and thermal transfer fluid storage chamber 73 are all clearly evident. In this embodiment, after placing the distal end of the catheter into the reconfiguration chamber, the nozzle 74 may be used to inject thermal transfer fluid into the reconfiguration chamber 70 in order to adjust the temperature of the coating resident on stent 76 . In this embodiment, the thermocouple 78 may be used to monitor the temperature of the thermal transfer fluid leaving the reconfiguration chamber such that the stent resident within the reconfiguration chamber 70 may be adjusted to a desired target temperature. In this embodiment, the uptake 72 may be positioned near the exit of the reconfiguration chamber 70 and may be used to capture thermal transfer fluid leaving the reconfiguration chamber in a thermal transfer fluid storage chamber 73 for subsequent disposal or reuse. [0040] Although not illustrated in this figure, the thermocouple 78 may be in communication with a controller to act in conjunction with it as a means for adjusting and maintaining the temperature of the coating. [0041] [0041]FIG. 8 is a side view of an alternative reconfiguration chamber in accord with another alternative embodiment of the present invention. Illustrated in FIG. 8 are thermal transfer fluid storage chambers 850 and 852 , entrance tube 81 , couple ring 83 , catheter 89 , nozzles 82 , stent or work-piece 86 , fluid flow arrows 87 , slidable outer walls 85 , thermocouple 88 , and uptake 851 . While similar to the embodiment in FIG. 7, the embodiment of FIG. 8 utilizes a couple ring 83 in fluid communication with numerous nozzles 82 that travel through the slidable outer walls 85 . These nozzles direct the thermal transfer fluid into the reconfiguration chamber and may be designed to increase or decrease the velocity of the fluid's flow in relation to its velocity in the tube 81 . By increasing or decreasing the flow of the fluid, the thermal transfer rate between the fluid and the coating can be concomitantly increased or decreased. [0042] While several of the above embodiments describe a balloon expandable stent, self-expanding stents may also be crimped in accord with the processes described above. These self-expanding stents, rather than requiring the forces generated by the balloon catheter to expand them, are capable of expanding under their own power once they have been deployed. In FIG. 9, as can be seen, the stent, previously crimped by the processes described above to fit inside the sheath 90 , may be stored within the sheath 90 , where it will remain until it is deployed at a target site of the body. Upon being deployed, the sheath 90 may be removed thereby allowing the stent 91 to expand under its own forces. [0043] As described above and as shown in FIGS. 10 and 11, the slidable outer walls may contain conduits or lines for adjusting the temperature of the coating. [0044] In FIG. 10, which is a side sectional view of reconfiguration chamber 100 , the slidable outer walls 102 are shown with fluid conduits 101 . These fluid conduits may be looped and travel throughout the individual slidable outer walls and may contain a thermal transfer fluid to adjust the temperature of the slidable outer wall 102 . This fluid may be cooled air and may be pumped through the conduits by a pumping system (not shown). [0045] [0045]FIG. 11 is a side sectional view of a reconfiguration chamber 1 10 . Rather than providing for a fluid conduit as in FIG. 10, the slidable outer walls 112 in FIG. 11 contain electrical lines 111 . These electrical lines, like the conduits described above, may be used to raise the temperature of the coating rather than lower it to reach the desired resiliency or, alternatively, may be used to thaw the coating after the stent has been reconfigured and prior to its ejection from the reconfiguration chamber 110 . [0046] These conduits or lines may be used in place of the thermal fluid transfer methods described above or in addition to the thermal fluid transfer methods described above. In other words, the conduits or lines placed into the walls 102 and 112 may be the sole source of adjusting the temperature of the coating or they may be a supplement to thermal transfer fluid being pumped over the coating. These conduits and lines may also be classified as a means for adjusting and maintaining the temperature of the coating. [0047] Thermal conditioning of a coated work-piece during the reconfiguration of the work-piece is provided. While various embodiments have been conveyed, it will be evident to one of skill in the art that other embodiments, also within the spirit and scope of the present invention, are plausible.
Thermal regulation of a coated work-piece during the reconfiguration of the work-piece is provided. One method embodying the invention comprises placing an externally coated reconfigurable work-piece, whose hardness has been temporarily modified to resist damage during the reconfiguration of the work-piece, into a reconfiguration chamber of a reconfiguration apparatus and reconfiguring the work-piece from a first configuration to a second configuration via physical communication between the external coating of the reconfigurable work-piece and the reconfiguration apparatus.
Briefly summarize the invention's components and working principles as described in the document.
[ "TECHNICAL BACKGROUND [0001] The present invention regards protecting a coated work-piece during its manufacture or reconfiguration.", "More specifically the present invention regards reducing the probability of damaging the coating of a work-piece during the work-piece's manufacture by managing or regulating the temperature of the coating.", "BACKGROUND OF THE INVENTION [0002] Articles of manufacture are regularly coated for numerous and varying reasons.", "For example, they may be coated to protect them from the intrusive handling they may be subjected to during their manufacture or to protect them from the environmental effects they may endure after they are manufactured.", "In either of these, as well as in others, damage to the coating of a work-piece, resulting from the handling or reconfiguration of the work-piece, is an unwanted result.", "[0003] When the coating of a work-piece becomes scratched or otherwise damaged during the work-piece's manufacture, the scratches can promote the deterioration of the work-piece by exposing the work-piece's surface to its surroundings.", "Should the work-piece, upon its completion, be employed in a corrosive environment, the exposed surface of the finished product would be more vulnerable to corrosion than if its coating were completely intact.", "Moreover, the scratches and inconsistencies in the coating of the work-piece may also reduce the effectiveness of the finished product.", "For example, should the coating be used to uniformly deliver some type of releasable substance, inconsistencies in the surface of the coating can foster uneven and inconsistent delivery of the releasable substance to the deployed product's final surroundings.", "[0004] An expandable coated stent is one specific example of the coated work-pieces described above.", "Expandable stents are tube-like medical devices designed to support the inner walls of a vessel within the body of a patient.", "These stents are typically positioned within a targeted lumen of the body and then expanded to provide internal support for the lumen.", "These stents may be self-expanding or, alternatively, may require external forces to expand them.", "In either case they are typically deployed through the use of a catheter of some kind.", "These catheters typically carry the stent at their distal ends.", "In use, a practitioner will position the catheter's distal end near the target area of the lumen.", "Once properly positioned the stent will be deployed by the practitioner such that it comes to rest near or in direct contact with the inner walls of the lumen.", "There, the stent will remain to provide support for the lumen.", "[0005] Due to the interaction of the stent with the inner walls of the lumen, stents have been coated to enhance their effectiveness.", "These coatings may, among other things, be designed to facilitate the acceptance of the stent into its applied surroundings or to enable the delivery of therapeutic to the lumen and its surroundings.", "Thus, when the coating is haphazardly applied or has somehow been removed during the stent's manufacture, both the stent's longevity and its effectiveness can be reduced.", "[0006] The coatings on the stent may be applied at various times during its life cycle including its manufacture, its placement onto the distal end of the delivery catheter, and contemporaneous with the medical procedure.", "At each of these times the coating may be at risk of being scratched, damaged or otherwise removed from the surface of the stent.", "For example, during their manufacture, stents are often crimped onto the distal end of a delivery catheter.", "This crimping process requires the exertion of significant forces against the coating of the stent to facilitate a reduction in the stent's circumference to secure it to the catheter.", "During this crimping, the mechanical arms of a crimper may come in contact with the coating of the stent as they reduce the diameter of the stent.", "This compressive contact can scratch, indent, wipe-off or otherwise breach the integrity of the coating—an undesirable result.", "SUMMARY OF THE INVENTION [0007] Thermal regulation of a coated work-piece during the reconfiguration of the work-piece is provided.", "One method embodying the invention comprises placing an externally coated reconfigurable work-piece, whose hardness has been temporarily modified to resist damage during the reconfiguration of the work-piece, into a reconfiguration chamber of a reconfiguration apparatus and reconfiguring the work-piece from a first configuration to a second configuration via physical communication between the external coating of the reconfigurable work-piece and the reconfiguration apparatus.", "[0008] An apparatus embodying the invention includes a reconfiguration chamber, a nozzle in fluid communication with the reconfiguration chamber, a regulator in fluid communication with the nozzle, the regulator adapted to regulate the flow of a thermal transfer fluid, and a controller in communication with the regulator.", "Wherein the controller is adapted to send control signals to the regulator to maintain the surface temperature of the external coating of the reconfigurable work-piece within a predetermined temperature range and wherein the predetermined temperature range affords a predetermined minimum hardness for the external coating of the reconfigurable work-piece.", "BRIEF DESCRIPTION OF THE DRAWINGS [0009] [0009 ]FIG. 1 is a graph of volume versus temperature for an exemplary polymer coating.", "[0010] [0010 ]FIG. 2 is an enlarged partial side cross-sectional view of a reconfiguration chamber and a reconfigurable coated work-piece prior to the reconfiguration of the coated work-piece in accord with an embodiment of the present invention.", "[0011] [0011 ]FIG. 3 is the view of FIG. 2 shown during the reconfiguration of the coated work-piece in accord with an embodiment of the present invention.", "[0012] [0012 ]FIG. 4 is a cross-sectional view of a reconfiguration chamber shown prior to the execution of a work stroke in accord with an alternative embodiment of the present invention.", "[0013] [0013 ]FIG. 5 is a sectional view taken along line 5 - 5 of FIG. 4. [0014] [0014 ]FIG. 6 is another cross-sectional view of the reconfiguration chamber of FIG. 4 shown after a work stroke has been completed in accord with an alternative embodiment of the present invention.", "[0015] [0015 ]FIG. 7 is a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention.", "[0016] [0016 ]FIG. 8 is a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention.", "[0017] [0017 ]FIG. 9 is a side view of a self-expanding stent within a sheath as manufactured by a method in accord with another alternative embodiment of the present invention.", "[0018] [0018 ]FIG. 10 is an enlarged side cross-sectional view of a reconfiguration chamber in accord with another alternative embodiment of the present invention.", "[0019] [0019 ]FIG. 11 is an enlarged side cross-sectional view of a reconfiguration chamber in accord with another alternative embodiment of the present invention.", "DETAILED DESCRIPTION [0020] In one embodiment of the present invention the hardness or resilience of the coating of a work-piece is temporarily increased by adjusting its preexisting temperature to be closer to its glass transition temperature.", "Then, while the coating is in this temporarily hardened or more resilient state, the force required to reconfigure the work-piece is applied against the coating.", "By temporarily increasing the hardness of the coating through its change in temperature, the coating is better able to withstand the forces and pressures exerted upon it during the reconfiguration of the work-piece.", "Thus, the coating is more likely to remain intact both during the remainder of the manufacturing of the work-piece and after the work-piece has been completely manufactured and is employed for its intended purpose.", "[0021] [0021 ]FIG. 1 is a graph of volume versus temperature for a polymer that may be used as a coating in accord with one embodiment of the present invention.", "The temperature of the polymer is plotted along the x-axis 11 while its corresponding volume is plotted along the y-axis 10 .", "The glass transition temperature (T g ) 12 as well as the melting temperature (T m ) 13 are specifically labeled on the x-axis 11 of the graph.", "Also labeled in the graph is the line 18 representing the specific volume for a given temperature of this exemplary polymer.", "This line 18 has three phase ranges identified on it, the glass phase 14 , the super-cooled liquid phase 15 , and the liquid phase 16 .", "The crystalline property delineation line 17 for this exemplary polymer is also evident in FIG. 1. [0022] The exemplary polymer graphed in FIG. 1 is a typical polymer.", "It is comprised of chains or strings of molecules that are interwoven and able to move in and around one another.", "As the polymer cools the chains loose their ability to freely flow around and among one another, and, thus, the polymer becomes stiffer and decreases in volume.", "[0023] When the polymer temperature is within the liquid range 16 the chains of molecules comprising the polymer may move freely amongst one another and, consequently, the polymer behaves much like a liquid.", "As the temperature decreases, the thermal agitation among the molecules lessens and the volume of the liquid shrinks.", "This decrease in volume continues below the melting point (T m ) 13 of the polymer and into its super-cooled liquid range.", "Below the melting point (T m ) 13 , the chains of molecules may still flow around and among themselves but they do so at a lower rate than in the liquid phase.", "It is here, in this super-cooled liquid range, that the hardness and resiliency of the polymer will increase as its temperature approaches the glass transition temperature (T g ) 12 .", "When the temperature of the polymer reaches the glass transition temperature (T g ) 12 the polymer enters the glass phase 14 .", "Here, the polymer becomes more brittle than in the super-cooled liquid phase as the molecules can no longer continually rearrange themselves.", "Moreover, as is evident in the graph of FIG. 1, the rate of volume change in relation to temperature changes at this point as it is one constant above the glass transition temperature (T g ) 12 and a different constant below the glass transition temperature (T g ) 12 .", "[0024] [0024 ]FIG. 2 provides an enlarged partial cross-section of a slidable outer wall 20 of a reconfiguration chamber positioned near a reconfigurable work-piece 22 , prior to a work stroke, in accord with one embodiment of the present invention.", "In this embodiment, prior to the beginning of a work stroke, the slidable outer wall is not in contact with the coating 21 or the reconfigurable work-piece 22 as is evident by the existence of void 23 .", "[0025] [0025 ]FIG. 3 provides an enlarged cross-section of the slidable outer wall 20 and the reconfigurable work-piece 22 of FIG. 2 during a work stroke.", "As can be seen, the slidable outer wall 20 is in direct contact with the coating 21 of the reconfigurable work-piece 22 .", "As is also evident, most but not all of the void 23 is filled during the work stroke as some small areas of void 23 remain when the slidable outer wall 22 comes in contact with the coating.", "[0026] In order to increase the resiliency and hardness of the coating and to reduce the potential damage to it from the direct contact with the slidable outer wall 20 , the coating may be cooled to be within its super-cooled liquid range.", "By lowering the temperature of the coating 21 , closer to the glass transition temperature of the coating, the coating 21 can be sufficiently hardened to protect it from the forces generated by its direct contact with the slidable outer wall 20 .", "Due to this temporal hardening, the coating 21 may remain substantially intact on the work-piece and may be able to continue to protect the work-piece 22 during the remaining steps of its manufacture and, afterwards, as the work-piece is deployed for its intended use.", "[0027] The slidable outer wall 20 provided in FIGS. 2 - 3 may be any one of innumerable pinching, moving, or force exerting components of a manufacturing machine or process.", "Likewise, the reconfigurable work-piece may be any one of innumerable work-pieces or products of manufacture currently manufactured in modem manufacturing systems.", "In addition, the coating 21 may be one of numerous commercial or industrial coatings including various ceramics, polymers, and waxes.", "These polymers could include SIBS polymers (styrene-isobutylene-styrene) and any other suitable polymer.", "[0028] [0028 ]FIG. 4 is a cross-sectional view of a reconfiguration chamber 40 as may be used to crimp or crease a stent 42 onto the distal end of a balloon catheter 44 in accordance with an alternative embodiment of the present invention.", "As can be seen in FIG. 4, the reconfiguration chamber 40 has slidable outer walls 41 that are in physical communication with one another and define a hexagonal-like adjustable aperture.", "Resident within this aperture is the distal end of a balloon catheter 44 having an exterior wall 45 .", "A stent 42 , encircling the distal end of the balloon catheter 44 and having a coating 47 with an exterior surface of the coating 48 , is also pictured in FIG. 4. As can also be seen in this embodiment, the exterior surface of the coating 48 has a void 43 between it and the interior faces of the slidable outer walls 41 .", "This void 43 may exist both before and after the completion of a work stroke of the slidable outer walls 41 .", "The initial diameter of the stent 42 , prior to the completion of a work stroke, is indicated with the character d 1 and the numeral 49 .", "[0029] In this embodiment, the slidable outer walls 41 of the reconfiguration chamber 40 are activated to crimp the stent 42 onto the balloon catheter 44 .", "When activated, the slidable outer walls 41 slide towards one another and, thus, reduce the size of the aperture defined by them.", "As the aperture's diameter reaches the size of the exterior surface 48 of the coating 47 , pressure is begun to be exerted on the coating 47 of the stent 42 and the stent begins to be reconfigured.", "As the diameter of the aperture is further reduced so too is the cross-sectional diameter of the stent 42 .", "In order to retard damage to the coating 47 that contacts the slidable outer walls 41 , the temperature of the coating 47 has been adjusted either before placing the stent 42 into the reconfiguration chamber 40 or while the stent 42 is located within the reconfiguration chamber 40 .", "[0030] In this embodiment the temperature of the coating 47 is adjusted after the stent has been placed within the reconfiguration chamber 40 .", "Here, a thermally conductive fluid may be flushed through the void 43 and in contact with the coating 47 to adjust the coating's temperature.", "Dependant upon the ambient temperature, the coating's preexisting temperature, and the glass transition temperature of the coating, the temperature of the existing surface of the coating 47 may be either heated or cooled.", "In this embodiment the temperature of the coating is reduced through the introduction of cooled ultra-dry air into the void 43 until the desired resultant temperature of the coating 47 is achieved.", "Other cooling mediums may also be used including both compressible and non-compressible fluids.", "The desired resultant temperature may depend upon the glass transition temperature of the coating, the structural rigidity of the stent, the properties of the balloon catheter, and the anticipated future handling of the stent.", "The desired temperature or temperature range may be a percentage of the T g or it may be a specific range of quantified values.", "In this embodiment, the desired temperature range is approximately 20° Celsius above the glass transition temperature of the coating.", "[0031] In this embodiment, once the temperature of the coating has been adjusted to be within the desired temperature range, the slidable outer walls 41 may complete a work stroke by sliding inwardly and, consequently, reconfiguring the stent 42 from a first position having a diameter d 1 to a second position having a diameter d 2 (illustrated in FIG. 6).", "[0032] An insulating tube 46 is positioned around the slidable outer walls 41 and is clearly evident in FIG. 4. This insulating tube 46 provides additional thermal buffering between the potentially extreme temperatures generated within the reconfiguration chamber and its surroundings.", "The insulating tube 46 may be made from an insulating ceramic or any other suitable insulating material.", "The slidable outer walls 41 may also be designed to provide buffering between the extreme temperatures generated within the reconfiguration chamber and the surroundings.", "For example the slidable outer walls 41 may be made from materials such as Dupont™ Delrin™ (acetal homopolymer and copolymer) and Zirconium oxide ceramic which has been partially stabilized with Yttria to provide supplementary thermal buffering between the work-piece and the surrounding area.", "[0033] [0033 ]FIG. 5 is a side cross-sectional view taken along line 5 - 5 of the reconfiguration chamber 40 of FIG. 4. Various features of the reconfiguration tube 40 are evident in this illustration including the entrance tube 51 , the exit tube 53 , nozzles 52 and 54 , insulating tube 46 , coating 47 , thermal transfer fluid flow arrows 50 , thermal transfer fluid 55 , stent 42 , slidable outer walls 41 , balloon catheter exterior surface 45 , balloon catheter 44 , regulator 56 , and controller 57 .", "[0034] After the distal end of the catheter 44 has been placed within the reconfiguration chamber 40 , in order to adjust the temperature of the coating 47 , thermal transfer fluid 53 may be delivered through tube 51 and nozzle 52 into direct contact with the coating 47 .", "Then, after passing over the coated stent, the fluid 50 may be recaptured through nozzles 54 and exit tubes 53 where it can be stored or recycled back into the process.", "The thermal transfer fluid 55 may be introduced and circulated both prior to and during the reconfiguration of the stent 42 , although it is preferable that the flow of the thermal transfer fluid 55 be halted once the slidable outer walls 41 have begun to move.", "The thermal transfer fluid may be any one of numerous suitable fluids, including liquid nitrogen, water, liquid helium, dry air, nitrogen, helium, or any other suitable compressible and non-compressible fluids.", "[0035] After the crimping has occurred the slidable outer wall 41 may open and the thermal transfer fluid 55 may cease its flow through the chamber.", "The balloon catheter 44 may then be removed from the reconfiguration chamber 40 and its temperature permitted to return to the ambient temperature.", "Alternatively, the distal end of the catheter 44 , carrying the now crimped stent 42 , may be subjected to other manufacturing steps that may also benefit from the coating's temporally increased hardness.", "[0036] In this embodiment the regulator 56 and controller 57 act together as a means for adjusting and maintaining the temperature of the coating 58 although other configurations for this means are plausible.", "These components work together to adjust and maintain the temperature of the coating 47 .", "The amount of fluid flowing through the entrance nozzles 52 into the reconfiguration chamber may be monitored by the controller 57 .", "When the requisite flow is detected no action may be required.", "However, should the controller 57 determine that the rate of fluid flow should be adjusted, in order to adjust or maintain the temperature of the coating 47 , it may, as required, send a signal that opens or closes the regulator 56 .", "[0037] This means for adjusting and maintaining the temperature 58 can take numerous other configurations.", "For example, while it is illustrated as being comprised of regulators and controllers regulating the flow of fluid into the reconfiguration chamber, this means could, instead, comprise manually adjustable valves that are adjusted by an operator monitoring the temperature of the coating.", "Alternatively, this means could also be electrical coils or hollow thermal conduction tubes carrying a thermal conductive fluid such as liquid nitrogen.", "The coils in either case may be placed within the slidable outer walls 41 and may be used to provide the thermal adjustment of the coating of the stent via the regulation of the fluid or electrical current flowing through them.", "[0038] [0038 ]FIG. 6 provides an enlarged cross-sectional view of the reconfiguration chamber during a work stroke.", "As can be seen in FIG. 6 the slidable outer walls 41 , containing residual transfer fluid 55 in the voids 43 , have closed in on themselves and have reconfigured the stent 42 into a second position such that the diameter d 2 of the stent 42 is smaller than the diameter d 1 of the stent 42 in FIG. 4. Because the temperature of the coating was brought closer to its glass transition temperature, the coating has substantially retained its shape, has not been substantially damaged, and has adequately transferred the forces generated from the slidable outer walls to the stent 42 .", "[0039] [0039 ]FIG. 7 shows a side view of a reconfiguration chamber in accord with another alternative embodiment of the present invention.", "In FIG. 7, nozzle 74 , catheter 79 , stent 76 , flow arrow 77 , thermocouple 78 , slidable outer walls 75 , uptake 72 , and thermal transfer fluid storage chamber 73 are all clearly evident.", "In this embodiment, after placing the distal end of the catheter into the reconfiguration chamber, the nozzle 74 may be used to inject thermal transfer fluid into the reconfiguration chamber 70 in order to adjust the temperature of the coating resident on stent 76 .", "In this embodiment, the thermocouple 78 may be used to monitor the temperature of the thermal transfer fluid leaving the reconfiguration chamber such that the stent resident within the reconfiguration chamber 70 may be adjusted to a desired target temperature.", "In this embodiment, the uptake 72 may be positioned near the exit of the reconfiguration chamber 70 and may be used to capture thermal transfer fluid leaving the reconfiguration chamber in a thermal transfer fluid storage chamber 73 for subsequent disposal or reuse.", "[0040] Although not illustrated in this figure, the thermocouple 78 may be in communication with a controller to act in conjunction with it as a means for adjusting and maintaining the temperature of the coating.", "[0041] [0041 ]FIG. 8 is a side view of an alternative reconfiguration chamber in accord with another alternative embodiment of the present invention.", "Illustrated in FIG. 8 are thermal transfer fluid storage chambers 850 and 852 , entrance tube 81 , couple ring 83 , catheter 89 , nozzles 82 , stent or work-piece 86 , fluid flow arrows 87 , slidable outer walls 85 , thermocouple 88 , and uptake 851 .", "While similar to the embodiment in FIG. 7, the embodiment of FIG. 8 utilizes a couple ring 83 in fluid communication with numerous nozzles 82 that travel through the slidable outer walls 85 .", "These nozzles direct the thermal transfer fluid into the reconfiguration chamber and may be designed to increase or decrease the velocity of the fluid's flow in relation to its velocity in the tube 81 .", "By increasing or decreasing the flow of the fluid, the thermal transfer rate between the fluid and the coating can be concomitantly increased or decreased.", "[0042] While several of the above embodiments describe a balloon expandable stent, self-expanding stents may also be crimped in accord with the processes described above.", "These self-expanding stents, rather than requiring the forces generated by the balloon catheter to expand them, are capable of expanding under their own power once they have been deployed.", "In FIG. 9, as can be seen, the stent, previously crimped by the processes described above to fit inside the sheath 90 , may be stored within the sheath 90 , where it will remain until it is deployed at a target site of the body.", "Upon being deployed, the sheath 90 may be removed thereby allowing the stent 91 to expand under its own forces.", "[0043] As described above and as shown in FIGS. 10 and 11, the slidable outer walls may contain conduits or lines for adjusting the temperature of the coating.", "[0044] In FIG. 10, which is a side sectional view of reconfiguration chamber 100 , the slidable outer walls 102 are shown with fluid conduits 101 .", "These fluid conduits may be looped and travel throughout the individual slidable outer walls and may contain a thermal transfer fluid to adjust the temperature of the slidable outer wall 102 .", "This fluid may be cooled air and may be pumped through the conduits by a pumping system (not shown).", "[0045] [0045 ]FIG. 11 is a side sectional view of a reconfiguration chamber 1 10 .", "Rather than providing for a fluid conduit as in FIG. 10, the slidable outer walls 112 in FIG. 11 contain electrical lines 111 .", "These electrical lines, like the conduits described above, may be used to raise the temperature of the coating rather than lower it to reach the desired resiliency or, alternatively, may be used to thaw the coating after the stent has been reconfigured and prior to its ejection from the reconfiguration chamber 110 .", "[0046] These conduits or lines may be used in place of the thermal fluid transfer methods described above or in addition to the thermal fluid transfer methods described above.", "In other words, the conduits or lines placed into the walls 102 and 112 may be the sole source of adjusting the temperature of the coating or they may be a supplement to thermal transfer fluid being pumped over the coating.", "These conduits and lines may also be classified as a means for adjusting and maintaining the temperature of the coating.", "[0047] Thermal conditioning of a coated work-piece during the reconfiguration of the work-piece is provided.", "While various embodiments have been conveyed, it will be evident to one of skill in the art that other embodiments, also within the spirit and scope of the present invention, are plausible." ]
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser. No. 13/614,474, filed on Sep. 13, 2012, entitled “Nanoadhesion Structures for Sporting Gear,” which is a divisional of U.S. application Ser. No. 12/819,378, filed on Jun. 21, 2010 and issued as U.S. Pat. No. 8,424,474, entitled “Nanoadhesion Structures for Sporting Gear,” which is based upon and claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/218,735, filed on Jun. 19, 2009. The entire contents of each of these disclosures are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] Field of the Invention [0003] This invention relates to sporting gear having at least one surface equipped for nanoadhesion, more specifically to swimming goggles having a nanofiber surface to attach to the user's body, a shoe having a nanofiber surface on an outsole to attach to a nanofiber surface on a midsole, a nanoadhesive seam to connect panels as part of athletic apparel, and a nanofiber zipper. [0004] Description of the Related Art [0005] Today's sporting gear, including sporting apparel and sporting equipment, may be a combination of the latest innovations of technology from various scientific disciplines. The resulting products are a system of innovative advances all contributing to the performance, safety, and comfort of the athlete. One significant area to improve sporting gear is to attach different sporting gear components together or attach components to the wearer's body. Traditional processes to adhere components to each other and to the user have been imperfect. [0006] In the case of swimming goggles and scuba masks, suction and compression have been traditional approaches to adhere a mask to the user's upper face. However, swim goggles utilizing these approaches frequently leak water into a space between a goggle lens and user's eye causing the user to lose the ability to properly see out of that eye resulting in a loss of potential performance. The swim goggle user may tighten the goggles and thereby push the goggles further into the skin around the eyes in an effort to create a more durable watertight seal. Unfortunately there are negative consequences to tightening goggles because they frequently create red rings around the user's eyes and cause swelling in this skin area by limiting blood flow and lymphatic return. [0007] In the case of shoes, traditional chemical-based adhesives such as epoxy cement have permanently attached outsoles to lower midsoles. For users requiring new outsoles to repair those that have been worn down after miles of use, the practical solution has been to replace the whole shoes. [0008] In the case of athletic seams used in clothing, there is a need for a better technique to bind clothing together at a seam to supplement or replace mere thread. After repeated uses of an article of clothing in athletic events or practice events the thread used for seams may break or tear the adjacent clothing to cause the clothing to become unusable. [0009] In the case of zippers, there is a need for a better zipper. Metal zippers can tear at fabric and plastic zippers may mechanically jam and not allow either opening and/or closing. Further, zipper alternatives provide significant disadvantages. For example, hook and loop fasteners may attach to the wrong surface and cause surface damage. [0010] There has been previous attempts to create goggles having no leaks, shoes having replaceable outsoles, and apparel having more robust seams and zippers. Yet these efforts have produced sporting gear that suffers from either deficiencies in performance, comfort, or safety. [0011] There are adhesive systems in nature that have not been applied to sporting gear. For example, the adhesive system on the feet of some insects and lizards, such as Geckos, Anolis lizards, and skinks has attracted research interest. These organisms have been able to attach and detach their feet to climb smooth surfaces such as glass. The adhesion system involves the use of tiny slender natural protrusions known as setae (singular “seta”) attached to their feet. For example, a Tokay gecko lizard possesses seta having a diameter of five microns and a height of 110 microns. The seta may include a set of sub-protrusions which contact other surfaces and have even smaller dimensions. As these organisms climb up smooth surfaces such as glass, the setae help geckos form a temporary attachment so they do not slip and fall. Although aspects of a gecko-like adhesive system have been observed in nature, the technology has not yet been successfully applied to commercial products. [0012] Although foregoing research efforts have met with varying degrees of success, there remains an unresolved commercial need for more leak-proof swimming goggles, shoes with replaceable soles, and athletic apparel with more robust seams and zippers. SUMMARY OF THE INVENTION [0013] One aspect of the present invention may be to address and resolve the above limitations of conventional sporting gear. [0014] A man-made adhesive mechanism may be customized as part of sporting gear having a mounting surface that may be attached to a second surface. The adhesive mechanism may include a first plurality of nanofibers attached to the mounting surface. The first end of each nanofiber may be attached to the mounting surface using a flocking process along with the application of either thermal or radio frequency bonding. The second end of each of the first plurality of nanofibers may be placed in contact with the second surface not having nanofibers or a plurality of second nanofibers attached to the second surface to form a temporary attachment called nanoadhesion which may include a van der Waals force contribution. [0015] The nanoadhesion attachment may be detached by pulling the first plurality of nanofibers away at an angle from the second surface. Each nanofiber may include a fiber shaft less than 100 microns in length with a diameter of less than half a micron. [0016] In a first aspect, the present invention may be adapted to attach swimming goggles to the wearer's face. Goggles may include a lens component, also known as a lens cup, for each eye. A lens component may have a lens surface and a mounting surface. The mounting surface may be configured to form a seal with the skin around a wearer's eye. The mounting surface may be made of the same material as the lens surface or the mounting surface may be included as part of a lower modulus of elasticity material attached as part of the lens component. [0017] Nanofibers are attached to goggles at the mounting surfaces of each lens component and form a protrusion emanating from the mounting surface that contacts the skin around the wearer's eyes. The nanofibers may be attached around the entire perimeter or only in areas of the mounting surface that are prone to separate from the skin during use of the swimming goggles (such as to the right and left of the eye). The nanofibers may provide a nanoadhesion force to better keep the mounting surface attached to the skin during use and may easily be detached from the skin at the end of use by pulling the mounting surface away from the skin. [0018] In a second aspect, the present invention may be adapted to attach and detach components of an athletic shoe having an outsole, midsole assembly, and upper. The outsole contains a bottom surface to contact the ground and a top surface to contact the midsole assembly. The top surface of the outsole contains a first mounting surface with a first set of nanofibers attached. The midsole assembly may contain several components to provide shock absorption and stability such as a rear lower midsole, a directional cradle, and a primary midsole. A bottom surface of the midsole assembly may contain a second mounting surface having a second set of nanofibers attached. The outsole may be attached to the midsole assembly by bringing the first and second set of nanofibers together. [0019] Other sets of nanofibers and mounting surfaces may be included to attach the midsole assembly to the upper and/or the midsole components together. The attachment process allows worn components to be replaced and different components to be swapped out to provide several different shoe configurations for the same upper. The attachment process also improves manufacturing efficiency. [0020] The shoe assembly may include sunken surfaces and complementary three-dimensional shapes to define the mounting surfaces and to thereby assist in a mechanical interference to keep the outsole in place while the shoe may be used. Further the shoe may include seals and/or gaskets to keep contaminants such as dirt or water away from nanofibers. [0021] In yet a third aspect, the present invention may be adapted to create a nanofiber seam to attach woven panels to form various athletic gear such as shirts, jackets, shorts, pants, hats, socks, and/or shoes. Nanofibers may also be used to create attachments between garments, for example from a glove to a jacket or a coat to a pant, or a pant to a boot. [0022] An apparel item may be made up of various components (herein “panels”) that are attached at one or more seams. The panels are cut to the proper size. Panels may have nanofibers attached via the flocking process along an edge of each panel where a seam may be intended to join the panels. The nanofibers may be attached to one side or both sides of each of the edges. The panels are then attached by bringing the nanofibers in contact. The panels may also be folded over to allow additional nanofibers to come into contact and to be attached together. The nanofibers may be pulled apart to allow the panels to be orientated in a different position to each other. The seam may be supplemented by thread for strength. [0023] In yet a fourth aspect, the invention may be adapted to create a nanofiber-based zipper for athletic gear such as apparel, gym bags, footwear, and the like that contain panels as described above. The nanofiber zipper may be used to attach a first edge of a first panel with a second edge of a second panel. The first and second panels may have nanofibers attached via the flocking process along an edge of each panel where the nanofiber zipper may be intended to attach the panels. The nanofibers may be attached to one side of the first panel edge and to one side of the second panel edge. The panels are then attached by bringing the nanofibers in contact. The user may unzipper the nanofiber zipper by pulling the nanofibers apart at an angle through the use of a zipper slider that may be outfitted with a control handle. The nanofiber zipper may be supplemented by other fasteners such as traditional hooks or buttons. [0024] As should be apparent, the invention can provide a number of advantageous features and benefits. It is to be understood that, in practicing the invention, an embodiment can be constructed to include one or more features or benefits of embodiments disclosed herein, but not others. Accordingly, it is to be understood that the preferred embodiments discussed herein are provided as examples and are not to be construed as limiting, particularly since embodiments can be formed to practice the invention that do not include each of the features of the disclosed examples. BRIEF DESCRIPTION OF THE DRAWINGS [0025] A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: [0026] The invention will be better understood from reading the description which follows and from examining the accompanying figures. These are provided solely as non-limiting examples of the invention. In the drawings: [0027] FIG. 1 illustrates a nanofiber according to an embodiment of the present invention; [0028] FIGS. 2A-2E illustrate a process to attach the nanofiber to a mounting surface using an adhesive according to an embodiment of the present invention; [0029] FIGS. 3A-3E illustrate a process to attach the nanofiber to a mounting surface using heat or high frequency radio waves according to an embodiment of the present invention; [0030] FIG. 4A illustrates a pair of swimming goggles according to an embodiment of the present invention as viewed from the top; [0031] FIG. 4B illustrates the pair of swimming goggles according to an embodiment of the present invention as viewed from the front; [0032] FIG. 5A illustrates the swimming goggle according to an embodiment of the present invention as viewed from the back; [0033] FIG. 5B illustrates the swimming goggle according to an embodiment of the present invention as viewed from the top and including a close-up of nanofibers attached; [0034] FIG. 6A illustrates a swimming goggle according to an embodiment of the present invention without a head band as viewed from the back; [0035] FIG. 6B illustrates the swimming goggle according to an embodiment of the present invention without a head band as viewed from the top and including a close-up of nanofibers attached; [0036] FIG. 7A illustrates a ski goggle according to an embodiment of the present invention without a head band as viewed from the front; [0037] FIG. 7B illustrates the ski goggle according to an embodiment of the present invention without a head band as viewed from the top and including a close-up of nanofibers attached; [0038] FIG. 8A illustrates a set of skin areas or regions designed to be in contact with the swimming goggles according to an embodiment of the present invention as viewed from the front; [0039] FIG. 8B illustrates a skin area or region designed to be in contact with the ski goggle according to an embodiment of the present invention as viewed from the front; [0040] FIG. 9 illustrates a shoe having components attached by nanofibers according to an embodiment of the present invention as viewed from the side; [0041] FIG. 10 illustrates a lower from the shoe having components attached by nanofibers according to an embodiment of the present invention as viewed from the upper side; [0042] FIG. 11 illustrates a pair of mounting surfaces being attached by nanofibers connected to each of the mounting surfaces according to an embodiment of the present invention as viewed from the side; [0043] FIG. 12 illustrates an athletic garment having a seam and a zipper utilizing nanofibers according to an embodiment of the present invention as viewed from the front; [0044] FIG. 13A illustrates a set of two apparel panels having nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side; [0045] FIG. 13B illustrates the set of two apparel panels having nanofibers attached and folded according to an embodiment of the present invention as viewed from the side; [0046] FIG. 13C illustrates the set of two apparel panels having nanofibers attached, folded, and double-stitched with thread according to an embodiment of the present invention as viewed from the side; [0047] FIG. 14A illustrates a set of two apparel panels having double-sided and single-sided nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side; [0048] FIG. 14B illustrates the set of two apparel panels having double-sided and single-sided nanofibers attached according to an embodiment of the present invention as viewed from the side; [0049] FIG. 14C illustrates the set of two apparel panels having double-sided and single-sided nanofibers attached and double-stitched with thread according to an embodiment of the present invention as viewed from the side; [0050] FIG. 15A illustrates a set of two apparel panels having single-sided nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side; [0051] FIG. 15B illustrates the set of two apparel panels having single-sided nanofibers attached according to an embodiment of the present invention as viewed from the side, this FIG. 15B also illustrates the preferred embodiment of the nanofiber zipper; [0052] FIG. 15C illustrates the set of two apparel panels having single-sided nanofibers attached and double-stitched with thread according to an embodiment of the present invention as viewed from the side; [0053] FIG. 16A illustrates first and second nanofiber folds as part of a nanofiber zipper detached in an open state as viewed from the top; [0054] FIG. 16B illustrates first and second nanofiber folds as part of the nanofiber zipper attached in a closed state as viewed from the top; [0055] FIG. 17A illustrates a cross section of an upper section of a nanozipper slider showing first and second nanofiber folds as viewed from the top; [0056] FIG. 17B illustrates a cross section of a lower section of the nanozipper slider showing first and second nanofiber folds as viewed from the top; [0057] FIG. 18A illustrates the nanofiber zipper slider from the front; [0058] FIG. 18B illustrates the nanofiber zipper slider from the left; [0059] FIG. 18C illustrates the nanofiber zipper slider as part of the full nanofiber zipper; [0060] FIG. 19A illustrates a nanofiber watch attached to a wrist using a strap as viewed from the side; [0061] FIG. 19B illustrates the nanofiber watch attached to a wrist without the strap as viewed from the side; [0062] FIG. 19C illustrates the nanofiber watch attached to a wrist without the strap as viewed from the top; [0063] FIG. 19D illustrates the nanofiber watch with nanofibers attached and the wrist as viewed from the side; [0064] FIG. 20A illustrates a second device attached to an arm using a strap as viewed from the front; [0065] FIG. 20B illustrates the second device watch attached to the arm without the strap as viewed from the front; [0066] FIG. 20C illustrates the second device as viewed from the front; [0067] FIG. 20D illustrates the second device with nanofibers attached and the arm as viewed from the side; [0068] FIG. 21A illustrates the second device attached directly to a piece of clothing using nanofibers as viewed from the front; [0069] FIG. 21B illustrates the second device as viewed from the front; [0070] FIG. 21C illustrates the second device with nanofibers attached and the piece of clothing as viewed from the side; and [0071] FIG. 21D illustrates the second device with nanofibers attached and the piece of clothing with nanofibers attached as viewed from the side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0072] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views. [0073] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts. [0074] FIG. 1 illustrates an adhesive protrusion hereafter known as a nanofiber preferably having a length from 5 to 100 microns in length. The nanofiber diameter may be preferably 0.05 times its length which may range from 250 nanometers to a micron. A first terminal end 22 of a nanofiber shaft 23 may not be attached to a mounting surface. The opposite terminal end 24 of the nanofiber shaft may be attached to a mounting surface via an adhesive or other attachment method such as thermal or high frequency radiation induced bonding or the like. [0075] When the first terminal end 22 of the nanofiber 20 contacts another surface, attraction forces, including van der Waal forces, adhere the nanofiber end 22 to the other surface. The other surface may also have a second nanofiber attached by adhesive that adheres to the nanofiber and/or the mounting surface. The attraction forces produced by contact with the nanofiber is referred here as nanoadhesion. The resulting attraction forces mimic the action of setae on a gecko's foot. [0076] The nanofibers are constructed using various methods. These methods generally involve casting or molding the fibers, growing them in a solution, or deposition. One method may be to use lithography methods where a recess may be etched in a semiconductor substrate and nitride and oxide layers are deposited on the substrate. The surface then may be patterned and etched. When the underlying structure is etched, a stress difference between the oxide and nitride layers causes the structure to curl and to form a shaft structure. The ends 22 of the shaft may be roughened to increase surface area available for contact by using wet etching, radiation, plasma roughening, electrochemical etching and others. [0077] A preferred method of making nanofibers involves creating yarns of sub-micron diameter fibers. These yarns may be cut from the yarns to release the fibers in lengths such that when adhered to a mounting surface, in a position perpendicular to the mounting surface, the nanofiber will not collapse under its own weight. [0078] The nanofibers may be then collected and prepared for attachment to the mounting surface. The nanofibers may be cleaned to remove contaminants and then chemically treated to accept an electric charge. The nanofibers may be spin-dried and then oven-dried to a specific moisture content. Conductivity may depend on moisture content, so it may be preferable that some moisture remain with the nanofibers. The nanofibers 20 are then packaged in moisture-proof containers 4 to maintain optimal moisture until a later attachment of the nanofibers 20 to a mounting surface. [0079] The nanofibers 20 may then be attached to a mounting surface via a flocking process. There are various types of flocking methods available, but an electrostatic-based flocking method may be preferred for attaching nanofibers to a mounting surface because of its ability to better align the nanofibers to the mounting surface. [0080] Two electrostatic-based flocking processes are preferred for permanently attaching the nanofibers 20 to the mounting surface. The first process involves an adhesive to attach the nanofibers 20 to the mounting surface and the second process involves heat instead of the adhesive. [0081] In the first process shown in FIGS. 2A to 2E , the flocking process begins by applying a chemically-compatible adhesive to the mounting surface which has been properly cleaned. In the case of a textured mounting surface having peaks and valleys, the adhesive may only be applied to the peaks. Various adhesives may be used such as: a low viscosity ultra-violet cure epoxy, uncured silicone rubber, polyurethane resin, plastisol (polyvinyl chloride particles suspended in a plasticizer), or the like. [0082] As shown in FIG. 2B , the adhesive may be applied to the mounting surface in the area(s) where the nanofibers 20 are desired to be attached. The adhesive thickness applied may be dependent upon the adhesive used and the mounting surface. A statistical process control methodology may begin with a preferred adhesive thickness that may be approximately ten times the shaft diameter of the nanofiber. The thickness may then be adjusted to optimize the reliability of the adhesive to hold the nanofiber and the efficacy of the final product. [0083] This methodology will create a scaled fiber assembly substantially similar to that encountered in nature within the gecko's foot, and in a manner that lends itself to large scale industrial production. [0084] After the adhesive 3 may be applied, the mounting surface 2 may be placed between the flock hopper 5 and a grounded electrode 8 as shown in FIG. 2C . The flock hopper 5 may be filled with the many nanofibers transferred from the moisture-proof containers 4 . The flock hopper 5 may have rotating flock stirrers with a plurality of arms configured to allow the nanofibers 20 to become airborne randomly to produce a uniform pattern at the exit of the hopper. The airborne nanofibers may then pass through an electrode grid 6 at the exit of the flock hopper which imparts a charge on the airborne nanofibers 20 that is an opposite electric charge compared to the grounded electrode 8 . [0085] The temperature and humidity of the flocking environment may be critical in controlling the charge on the airborne nanofibers. Humidity too low may cause the nanofibers to not effectively take on an electrical charge and humidity too high may cause the nanofibers to undesirably stick or clump to each other. These humidity and temperature levels may be optimized according to the nanofiber characteristics and the adhesive used. [0086] Once the nanofibers 20 are electrically-charged and released from the flock hopper 5 to be airborne above the mounting surface as elements 7 , the nanofibers 7 will align themselves with the magnetic field between the electrodes 6 , 8 and accelerate towards an oppositely-charged electrode 8 arranged below the mounting surface 2 . The aligned and accelerated nanofibers 7 collide with and embed into the adhesive 3 in a position substantially perpendicular to the mounting surface 2 . [0087] Alternatively, the adhesive may be electrically charged instead of having a grounded electrode beneath the mounting surface. The nanofibers 20 would similarly embed into the adhesive 3 in the position substantially perpendicular to the mounting surface 2 . [0088] As shown in FIG. 2D , the mounting surface 2 may then be removed from between the flock hopper 5 area and excess nanofibers 21 which are not embedded into the adhesive 3 may be removed via vacuum 9 or other suction device. The adhesive 3 may be allowed to cure and the nanofibers 20 remain attached and generally perpendicular to the mounting surface as shown in FIG. 2E . [0089] The second process may be shown in FIGS. 3A to 3E . The nanofibers 20 used in this process may be made of thermoplastic which may form a bond with the mounting surface 2 greater than a certain temperature. Various thermoplastics may be used such as Poly(methyl methacrylate) or PMMA, polyethylene (PE), Polystyrene (PS), or the like. [0090] As represented in FIG. 3A , the mounting surface 2 may first be prepared for the attachment of the nanofibers 20 by cleaning using surfactants or other cleaning agents available to remove contaminants that may inhibit the subsequent process steps. Next, as shown in FIG. 3B , the mounting surface 2 may be heated. The heater 10 may be an oven, a frequency radiation emitter, or the like. The heater 10 may use heating means 11 such as radiation heat transfer or convention heat transfer to heat the mounting surface 2 to a temperature above the melting point of the material used to make the nanofibers 20 . For example, the melting point of PMMA is approximately 135 degrees Celsius, polyethylene is between 105 to 130 degrees Celsius, and polystyrene melts at roughly 240 degrees Celsius. [0091] After heating, the mounting surface 2 may be placed between the flock hopper 5 and a grounded electrode 8 as shown in FIG. 3C . The flock hopper 5 may be filled with the many nanofibers transferred from the moisture-proof containers 4 . The flock hopper 5 converts the nanofibers 20 into airborne nanofibers 7 which then pass through an electrode grid 6 at the exit of the flock hopper to impart a charge on the airborne nanofibers 20 that is an opposite electrical charge compared to that of the grounded electrode 8 . [0092] Once the airborne nanofibers 7 are electrically-charged and released from the flock hopper 5 to be airborne above the mounting surface, they will align themselves with the magnetic field between the electrodes 6 , 8 and accelerate towards an oppositely-charged electrode 8 arranged below the substrate 2 . The aligned and accelerated nanofibers 7 collide with the heated mounting surface 2 and nanofibers 7 partially melt at the contact point between the nanofibers 20 and the heated mounting surface 2 to form a permanent attachment point. [0093] The mounting surface 2 may then be removed from between the flock hopper 5 area and the excess nanofibers 21 that are not attached to the mounting surface 2 are removed via vacuum 9 or other suction device as shown in FIG. 3D . The mounting surface 2 may be allowed to cool and the nanofibers 20 remain attached and generally perpendicular to the mounting surface as illustrated in FIG. 3E . First Embodiment—Nanofiber Swimming Goggles [0094] Sporting gear provides useful applications for nanoadhesion. In the first embodiment, swim goggles are commonly used to enable swimmers to keep water out of their eyes. The swim goggles 101 are illustrated in FIGS. 4A to 7B . The swim goggles 101 may include two eye components 102 , a nose bridge 108 and a head band 104 . The nose bridge 108 may be designed to hold each of the eye components 102 a fixed distance apart. The head band 104 may fit around the head of the wearer and be attached at each end to the eye components 102 . Each eye component 102 may include a lens surface 103 , a connector interface 107 , a head band interface 105 , and a sealant surface 106 . The connector interface 107 may connect the nose bridge 108 to the eye component 102 . The head band interface 105 may connect the head band 104 to the eye component 102 . The sealant surface 106 may contact a skin contact area 123 , 124 of the left or right eye 121 , 122 as shown in FIG. 8A . The shape of the sealant surface 106 may be similar to the shape of the skin area 123 , 124 to allow contact all around the eye 121 , 122 . The sealant surface 106 may be the same material as the lens surface 103 . [0095] As shown in FIG. 5B , the sealant surface 106 may have many nanofibers 20 attached at the terminal end 24 . The unattached terminal ends 22 of the nanofibers 20 are configured to contact the skin contact area 123 , 124 when the goggles 101 are worn by a user and thereby form a nanoadhesion attachment with the skin contact area 123 , 124 . [0096] The nanofibers 20 are not configured to penetrate the skin contact area 123 which is composed of several skin layers including the epidermis and dermis. The human epidermis is the outer skin layer and its minimum thickness is 50 microns at the eyelids. The human epidermis has five sub-layers and the cells divide at the inner layers and are gradually pushed to the exterior layers where their cells flatten and die to be shed every two weeks. The nanofibers 20 may be configured to merely contact the outer layers of the epidermis to avoid skin injury. [0097] Another embodiment of the goggles may have a rubber gasket. The rubber gasket may act as the sealant surface 106 and may be merely attached to the eye component 102 via adhesive such as epoxy cement or the like. The gasket 106 may be made from rubber, silicone, or other soft material. One end 24 of each nanofiber 20 may be permanently attached to the rubber gasket 106 using one of the flocking processes 1 , 12 . The skin contact area 123 , 124 contacts the unattached end 22 of the nanofibers 20 when the swim goggles 101 are worn and a nanoadhesion attachment may be made between the nanofiber 20 and the skin contact area 123 , 124 . [0098] Embodiments of the goggles 101 are intended to be used by the wearer in a similar way. The wearer places the eye components 102 , 109 over the eyes 121 , 122 , so that the end 22 of the nanofibers 20 attached to the sealant surface 106 contacts the skin contact area 123 . The wearer then fastens the head band 104 around the wearer's head to provide a comfortable fit which pulls the sealant surface 106 against the skin 123 in order to form a watertight seal. The wearer may also slightly depress the eye component 102 against the skin 123 to force a small amount of air to be pushed out from between the eye compartment 102 and the eye 121 . When this air is pushed out, the watertight seal keeps the air from returning and thereby maintains a negative suction between the eye component 102 and the corresponding eye 121 to improve the watertight seal. The negative suction is an absolute pressure less than ambient pressure. The user may also depress the eye component 109 to achieve a similar negative suction to improve the watertight seal related to the other eye 122 . [0099] As the wearer engages in a water activity involving immersing the user's head and swim goggles 101 in water, the watertight seal may be maintained because the skin 123 remains in contact with the sealant surface 106 as a result of the negative suction, the pull of the head band 104 , and the nanoadhesion attraction between the nanofibers 20 and the skin 123 . This watertight seal may be more robust than goggles without nanofibers 20 , because as the wearer engages in vigorous activities while wearing the goggles 101 the tight seal may be vulnerable to compromise as the contact skin area 123 changes shape relative to the sealant surface 106 during the water activity. [0100] When the water activity has been completed, the wearer merely releases the head band 104 from the back of the wearer's head and the wearer pulls the eye components 102 , 109 from the skin contact areas 123 , 124 . [0101] A second aspect to this first embodiment may be swim goggles without a head band 104 , connector interface 107 , and nose bridge 108 as shown in FIGS. 5A and 5B . In this second aspect, each eye component 102 is identical to each other and has nanofibers 20 attached to the sealant surface 106 . Just prior to the wearer engaging in a water activity involving immersing the user's head and swim goggles in water, an eye component is placed in contact with each of the respective skin areas 123 , 124 so that the nanofibers 20 are in contact with the respective skin areas 123 , 124 . A watertight seal may be maintained as described with respect to a single eye component because the skin 123 remains in contact with the sealant surface 106 as a result of negative suction and the nanoadhesion attraction between the nanofibers 20 and the skin 123 . When the water activity has been completed, the wearer merely pulls each eye component from the respective skin areas 123 , 124 . [0102] As shown in FIGS. 7A and 7B , ski goggles may be a second aspect of this first embodiment. The ski goggles 130 may include a lens 131 and a sealant surface 132 . The ski goggles 130 may or may not also include a strap (strap not shown). The sealant surface 132 has nanofibers 20 attached using at least one of the flocking processes mentioned earlier. Just prior to the wearer engaging in a skiing activity, the nanofibers 20 are placed in contact with a skin area 125 as shown in FIG. 8B . A nanoadhesion attraction between the skin area 125 and the nanofibers 20 is created which keeps the ski goggles 130 attached to the skin area 125 . When the skiing activity has been completed, the wearer merely pulls the sealant surface 132 away from the skin area 125 . Other sports goggles, prescription or non-prescription, are also embodied in this application and can be similarly constructed. [0103] In yet another embodiment, the sealant surface 132 having nanofibers 20 may be located instead on a waistband or shirt cuff to grip the nearby skin better. Second Embodiment—Replaceable Shoe Components [0104] Another embodiment utilizing the nanofibers 20 is illustrated in FIG. 9 as an athletic shoe 200 having an upper 201 and a lower 202 . FIG. 10 shows the lower 202 for a left foot, but the right shoe has a similar construction. The lower 202 may include a full-length primary midsole 210 , a directional cradle 211 , a first cushion 212 , a second cushion 213 , a third cushion 214 , a rear lower midsole 215 , a rear outsole 220 , a lateral outsole 221 , a medial outsole 222 , a center outsole 223 , and a front outsole 224 . The directional cradle 211 may be attached to the primary midsole 210 . The cushions 212 , 213 , 214 may be attached to both the directional cradle 211 and the rear lower midsole 215 . The components of the outsole 220 , 221 , 222 , 223 , 224 may be attached to the rear lower midsole 215 , directional cradle 211 , and/or primary midsole 210 . Any of the components that are part of the lower 202 may be attached together where as shown in FIG. 11 a first set of nanofibers 241 are permanently attached to first mounting surface 240 and a second set of nanofibers 231 are permanently attached to a second mounting surface 230 via the flocking processes 1 , 12 . The mounting surfaces 230 , 240 may be part of the components of the lower 202 . Then, using the process of nanoadhesion, the first and second nanofibers 231 , 241 are placed in contact as the components of the lower 202 are placed in contact to form a nanoadhesion attachment. The attachment may be temporary because the user may pull the lower components (elements 210 - 215 and/or 220 to 224 ) apart to remove or replace the component with a second component. [0105] The nanoadhesion embodiments of shoe 200 are intended to be used by the wearer in a similar way. The wearer inserts her foot into the upper 201 and fastens the upper 201 comfortably to the foot so the foot may be disposed between the upper 201 and the lower 202 . The wearer may engage in whatever activity desired so that the outsole components 220 , 221 , 222 , 223 , 224 may have a set of impacts with the ground. [0106] When the activity has been completed, the upper 201 may be unfastened and the wearer's foot removed from the shoe 200 . When one or more of the components of the lower 202 become worn beyond repair and need to be replaced, then the wearer will pull the set of nanofibers 231 permanently attached to the worn component from the set of nanofibers 241 attached to another component. Next, the wearer may attach a replacement component having a new set of nanofibers 231 on a mounting surface 230 to the old corresponding set of nanofibers 241 on the other component by bringing them in contact. Third Embodiment—Nanofiber Seams [0107] Yet another embodiment may be to produce a nanofiber seam to connect woven panels as part of athletic gear such as shirts, jackets, shorts, pants, hats, socks, and/or shoes. Various seam configurations may be created with nanofibers. For example, FIG. 12 illustrates an athletic shirt 300 having a first woven panel 310 and a second woven panel 320 attached by a nanofiber seam 301 . [0108] The woven panels 310 , 320 may first be cut to the proper size prior to being attached by the seam 301 . The woven panel 310 has a top side 312 and a bottom side 313 as shown in FIG. 13A . The woven panel 320 has a top side 322 and a bottom side 323 . The panels 310 , 320 may have nanofibers 231 , 241 attached via the flocking process 1 , 12 along an edge of each panel where a seam may be intended to join the panels. The nanofibers 231 may be attached to one side of the panel 310 at a panel edge 311 as shown by FIG. 13A . The nanofibers 241 may be permanently attached to one side of the panel 320 at a panel edge 321 using the flocking process 1 , 12 . The panels 310 , 320 are then attached by bringing the nanofibers 231 , 241 in contact at the panel edges 311 , 321 . FIG. 13B shows the attached panel edges 311 , 321 after being folded over. FIG. 13C shows thread stitches 302 , 303 added to add strength and to form a nanofiber seam 304 . Prior to the stitching 302 , 303 being applied, the nanofibers 231 , 241 may be pulled apart to allow the panels 310 , 320 to be reattached in case they have been incorrectly positioned together the first time. [0109] In yet an alternative embodiment, the nanofibers 231 , 241 may be attached to the panels 310 , 320 in both single-sided 412 , 422 and double-sided 411 , 421 nanofiber areas as shown in FIG. 14A . In this embodiment two of the double-sided nanofiber areas 411 , 421 are first placed in contact, then folded over to allow the remaining two double-sided nanofiber areas 411 , 421 to attach to the single-sided nanofiber areas 412 , 422 as shown in FIG. 14B . Threaded stitching 402 , 403 may be added for strength and to form a second nanofiber seam 404 as shown in FIG. 14C . [0110] In another embodiment, a nanofiber seam 504 may be produced by attaching nanofibers to panels, 310 , 320 to form a set of single-sided nanofiber areas 511 , 521 as shown in FIG. 15A . The nanofiber panel edges 511 , 521 are attached together using nanoadhesion by being placed in contact as shown in FIG. 15B . Stitching 502 , 503 is applied to add further strength to the nanofibers and thereby produce the nanofiber seam 504 as shown in FIG. 15C . [0111] The nanofiber seams 304 , 404 , 504 , may be used by apparel designers to construct various athletic gear products from one or more woven panels. When the athletic gear is utilized by the final user, the nanofiber seam should keep one or more woven panels reliably together. [0112] In yet another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to reconfigure a pocket on clothing so that the location and the shape of the space that can be accommodated within the pocket may be changed by adjusting the contact area between the panel edges 511 and 521 at a perimeter of the pocket and clothing that the pocket is mounted upon. [0113] In a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to connect a jacket to pants, e.g., sporting apparel such as running jackets and pants, warm-up jackets and pants, and/or ski jackets and pants. This may improve warmth by keeping the wind out of the area between the jacket and the pants. The panel edge 511 may be on the bottom of the jacket edge and the panel edge 521 may be on the top of the pants as shown in the FIG. 15A . When the pants are attached to the jacket at the panel edges 511 , 521 , then the panels may create the nanoadhesion attachment as shown in FIG. 15B . [0114] In yet a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to connect cuff-tabs on shirt sleeves to eliminate the need for buttons. [0115] In another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to adjust the size of air vents in clothing so that the user may decide to enlarge vents during strenuous activity and then reduce the size of the vents after the activity has finished. [0116] In a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to attach and detach removable clothing elements, such as hoods and sleeves. [0117] In yet another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to attach and detach packaging components so the packaging closure may be curved instead of straight. Fourth Embodiment—Nanofiber Zipper [0118] Yet another embodiment that may utilize the nanofibers 20 in sporting gear is a nanofiber zipper 600 , as shown in the athletic shirt 300 shown earlier in FIG. 12 . The zipper may also be adapted for use in athletic gear such as apparel, gym bags, footwear, and the like. [0119] The nanofiber zipper 600 may be illustrated in FIGS. 12, 16A, 16B and 18C where the nanofiber zipper may be configured to detach a first panel edge 606 from a second panel edge 616 ( FIG. 16A ) and then later reattach the panels 606 , 616 ( FIG. 16B ). The first panel 606 includes both a top side 607 and a bottom side 608 . The second panel 616 includes both a top side 617 and a bottom side 618 . The nanofiber zipper 600 may include a zipper slider 630 configured to open and close the zipper, a first nanofiber fold 602 as part of first panel edge 606 , a first set of nanofibers 603 attached as part of first panel edge 606 , a second nanofiber fold 612 as part of second panel edge 616 , and a second set of nanofibers 613 attached as part of second panel edge 616 . The nanofiber zipper 600 may include a first set of thread stitches 604 , 605 to add strength to the first nanofiber fold 602 and a second set of thread stitches 614 , 615 to add strength to the second nanofiber fold 612 . The first nanofiber fold 602 may include a top fold side 620 and a bottom fold side 621 . The second nanofiber 612 fold may include a top side 622 and a bottom side 623 . [0120] The first and second nanofiber folds 602 , 612 as well as the first and second nanofibers 603 , 613 may be created and attached using the same concepts already discussed as part of the processes used to make the nanofiber seams 304 , 404 , 504 . [0121] FIGS. 16B and 17B show the nanofiber zipper 600 in the closed state where the nanofibers on the first nanofiber fold 602 have attached to the second set of nanofibers 613 using nanoadhesion. Also, the nanofibers on the second nanofiber fold 612 have attached to the first set of nanofibers 603 using nanoadhesion. [0122] The zipper slider 630 opens and closes the zipper 600 and includes a control handle (not shown) for the user to control the zipper 600 . The control handle may be attached at an attachment point 650 as shown in FIGS. 18A, 18B, and 18C . [0123] FIGS. 17A and 18A show a cross section at the top 651 of the zipper slider 630 where the panel edges 606 , 616 are unattached to each other. The first and second nanofiber folds 602 , 612 are used to guide the panel edges 606 , 616 through the zipper slider 630 . FIG. 17B shows a cross section at the bottom 652 of the zipper slider 630 where the panel edges 606 , 616 are attached via nanoadhesion. [0124] A close-up of the zipper slider 630 is shown at FIG. 18A . The slider top 651 is wider than the slider bottom 652 . FIG. 18B shows the left side of the zipper slider 630 with an open groove 652 for the first panel edge 606 to travel. [0125] The nanofiber zipper 600 may be supplemented by other fasteners such as traditional hooks or buttons. [0126] The nanofiber zipper 600 is operated by the user by grabbing a control handle (not shown) attached to the 650 attachment at the zipper slider 630 . The user moves the zipper slider 630 up 700 along the length of the panel edges 606 , 616 to close the zipper 600 . The user may open the zipper 600 by moving the zipper slider 630 down 701 along the length of the panel edge 606 , 616 and the nanofibers on the panel edges 606 , 616 may be pulled apart by the zipper slider. The process is reversible and the zipper 600 may be opened and closed many times. [0127] Although various zipper embodiments are possible with nanoadhesion, the preferred embodiment is shown in FIGS. 15A-15B . The preferred zipper includes panels 310 , 320 with nanofibers attached at nanofiber panel edges 511 , 512 . The nanofiber panel edges 511 , 521 are attached together using nanoadhesion by being placed in contact as shown in FIG. 15B . The nanofibers panel edges 511 , 512 may be later detached by pulling them apart. Fifth Embodiment—Device Attachment [0128] Yet another embodiment that may utilize the nanofibers 20 in sporting gear is a nanofiber attachment, as demonstrated by a wristwatch 800 in FIG. 19A . The nanofiber attachment may be adapted for other devices other than wristwatches, for example, global positioning system devices, music players or video entertainment devices, communication devices, heart rate monitors, biometric sensors, and the like. [0129] The nanofiber watch 800 may include a strap 801 while worn on the wrist 126 or may be attached to the wrist 126 directly using nanofibers 20 as shown in FIGS. 19B-19D . The watch 800 includes nanofibers 20 that may be attached using one or more of the flocking processes 1 , 12 discussed earlier. The watch 800 may be attached directly to the wrist 126 by placing the nanofibers 20 in contact with the 126 or arm 127 to form a nanoadhesion attachment. The wearer engages in whatever activities desired and the nanoadhesion attachment keeps the watch 800 attached to the wrist 126 . When the watch 800 is to be removed from the wrist 126 , then the wearer may pull the watch 800 away from the wrist 126 to separate the nanofibers 20 from the wrist 126 . [0130] A second aspect to the device attachment is to attach a second device 810 to the arm 127 as shown in FIG. 20A-20D . The second device may be a time measuring device, heart monitor, location device, music or video entertainment device, medical sensor, athletic performance measuring sensor, communication device, or the like. The second device 810 may include a strap 811 while worn on the arm 127 or may be attached to the arm 127 directly while solely using nanofibers 20 . The second device includes nanofibers 20 that may be attached using one or more of the flocking processes 1 , 12 discussed earlier. The second device 810 may be attached directly to the arm 127 by placing the nanofibers 20 in contact with the arm 127 to form a nanoadhesion attachment. The wearer engages in whatever activities desired and the nanoadhesion attachment keeps the second device 810 attached to the arm 127 . When the second device 810 is to be removed from the arm 127 , then the wearer may pull the second device 810 away from the arm 127 to separate the nanofibers 20 from the arm 127 as shown in FIG. 20D . [0131] In a third aspect to the device attachment embodiment, a second device 810 is attached to a piece of clothing 812 as shown in FIGS. 21A-21C . The second device 810 may be attached directly to the clothing 812 . The user merely attaches the second device 810 to the clothing 812 so that the nanofibers 20 on the device 810 come in contact with the clothing 812 to form a nanoadhesion attachment. When the second device 810 is to be removed from the clothing 812 , then the wearer may pull the second device 810 away from the clothing 812 to separate the nanofibers 20 from the clothing 812 as shown in FIG. 21C . The piece of clothing 812 may be shirts, pants, socks, shoes, jackets, or the like. [0132] In yet a fourth aspect to the device attachment embodiment, the second device 810 is attached to a piece of clothing 812 having nanofibers 815 attached to the clothing 812 . In this aspect a nanoadhesion attachment is formed between the nanofibers 20 attached to the second device 810 and the nanofibers 815 attached to the clothing 812 using the one or more of the flocking processes described earlier. The user merely attaches the second device 810 to the clothing 812 so that the nanofibers 20 on the device 810 and the nanofibers 815 on the clothing 812 come in contact with each other to form a nanoadhesion attachment. The user engages in whatever activity is desired and the nanoadhesion attachment keeps the device 810 attached to the clothing 812 . When the second device 810 is to be removed from the clothing 812 , then the wearer may pull the second device 810 away from the clothing 812 to separate the nanofibers 20 , 815 as shown in FIG. 21D . [0133] In yet a fifth aspect to the device attachment embodiment, the second device 810 illustrated in either FIGS. 21C or 21D could be a component designed to cushion the impact of certain body parts during sporting activities. The component could be functionally equivalent to shin pads used by soccer players, modular protection zones used by football players on football pants and other protective gear, or localized padding used in biking shorts used by cyclists to lessen the shock and bumps from a bicycle seat to contact points on the human body. The component may have nanofibers 20 attached to the component and may have nanofibers 815 attached to the contact area on the clothing. [0134] In yet a sixth aspect to the device attachment embodiment, the second device 810 may be a backpack and a set of associated straps that may be attached to a wearer's clothing using nanofibers 20 attached to the associated straps. The nanofibers 20 may be attached to nanofibers 815 on the wearer's clothing to form a nanoadhesion attachment. An advantage of using nanofibers 20 , 815 to attach the straps to the clothing may be to reduce chafing during activity. Other embodiments may have a backpack without straps and the backpack attached directly to the clothing with a nanoadhesion attachment. [0135] In a seventh embodiment, a bottle closure (broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with a bottle (broadly represented as element 812 in FIG. 21C ) to replace threaded closures used on bottles, such as soda cans, water bottles, and the like. [0136] In an eighth embodiment, a roof rack may to interface with an automobile (the roof rack broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with an exterior surface of an automobile (broadly represented as element 812 in FIG. 21C ). The roof rack may be used to transport bicycles, boats, sporting equipment, packages in transit, or the like. [0137] In a ninth embodiment, a clothing hanger (the hanger is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with clothing that is desired to be hung from the hanger (the clothing broadly represented as element 812 in FIG. 21C ). The clothing may or may not have nanofibers to attach with those nanofibers 20 on the hanger. [0138] In a tenth embodiment, a clothing price tag or information tag (the tag is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with clothing that the tag is associated with (the clothing broadly represented as element 812 in FIG. 21C ). [0139] In an eleventh embodiment, a portion of a surface of a glove (the portion of the glove surface is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with an item that the glove is gripping while the glove is in the user's hand (the item is broadly represented as element 812 in FIG. 21C ). The item may be a basketball, water polo ball, a hockey stick, a tennis racquet, or other item similarly to be gripped by a glove. [0140] In a twelfth embodiment, a gripping surface (the gripping surface broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with a surface of a hand or glove (the surface of the hand or glove broadly represented as element 812 in FIG. 21C ). The gripping surface may be a hockey stick gripping area, a tennis racquet grip, or other surface similarly gripped by a glove or hand. The glove may also have nanofibers 20 attached to interface with the nanofibers on the gripping surface. [0141] Further, it should be appreciated that the exemplary embodiments of the invention are not limited to the exemplary embodiments shown and described above. While this invention has been described in conjunction with exemplary embodiments outlined above, various alternatives, modifications, variations and/or improvements, whether known or that are, or may be, presently unforeseen, may become apparent. Accordingly, the exemplary embodiments of the invention, as set forth above are intended to be illustrative, not limiting. The various changes may be made without departing from the spirit and scope of the invention. Therefore, the systems and methods according to exemplary embodiments of this invention are intended to embrace all now known or later-developed alternatives, modifications, variations and/or improvements. [0142] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
An apparatus including a first surface configured to attach the apparatus to a second surface of another object, and a plurality of elongated nanofibers. Each nanofiber has one end connected to the first surface and an opposite end extending away from the first surface. The plurality of elongated nanofibers is configured to adhere to the second surface by nanoadhesion when brought into contact with the second surface.
Provide a concise summary of the essential information conveyed in the given context.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. application Ser.", "No. 13/614,474, filed on Sep. 13, 2012, entitled “Nanoadhesion Structures for Sporting Gear,” which is a divisional of U.S. application Ser.", "No. 12/819,378, filed on Jun. 21, 2010 and issued as U.S. Pat. No. 8,424,474, entitled “Nanoadhesion Structures for Sporting Gear,” which is based upon and claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/218,735, filed on Jun. 19, 2009.", "The entire contents of each of these disclosures are incorporated herein by reference.", "BACKGROUND OF THE INVENTION [0002] Field of the Invention [0003] This invention relates to sporting gear having at least one surface equipped for nanoadhesion, more specifically to swimming goggles having a nanofiber surface to attach to the user's body, a shoe having a nanofiber surface on an outsole to attach to a nanofiber surface on a midsole, a nanoadhesive seam to connect panels as part of athletic apparel, and a nanofiber zipper.", "[0004] Description of the Related Art [0005] Today's sporting gear, including sporting apparel and sporting equipment, may be a combination of the latest innovations of technology from various scientific disciplines.", "The resulting products are a system of innovative advances all contributing to the performance, safety, and comfort of the athlete.", "One significant area to improve sporting gear is to attach different sporting gear components together or attach components to the wearer's body.", "Traditional processes to adhere components to each other and to the user have been imperfect.", "[0006] In the case of swimming goggles and scuba masks, suction and compression have been traditional approaches to adhere a mask to the user's upper face.", "However, swim goggles utilizing these approaches frequently leak water into a space between a goggle lens and user's eye causing the user to lose the ability to properly see out of that eye resulting in a loss of potential performance.", "The swim goggle user may tighten the goggles and thereby push the goggles further into the skin around the eyes in an effort to create a more durable watertight seal.", "Unfortunately there are negative consequences to tightening goggles because they frequently create red rings around the user's eyes and cause swelling in this skin area by limiting blood flow and lymphatic return.", "[0007] In the case of shoes, traditional chemical-based adhesives such as epoxy cement have permanently attached outsoles to lower midsoles.", "For users requiring new outsoles to repair those that have been worn down after miles of use, the practical solution has been to replace the whole shoes.", "[0008] In the case of athletic seams used in clothing, there is a need for a better technique to bind clothing together at a seam to supplement or replace mere thread.", "After repeated uses of an article of clothing in athletic events or practice events the thread used for seams may break or tear the adjacent clothing to cause the clothing to become unusable.", "[0009] In the case of zippers, there is a need for a better zipper.", "Metal zippers can tear at fabric and plastic zippers may mechanically jam and not allow either opening and/or closing.", "Further, zipper alternatives provide significant disadvantages.", "For example, hook and loop fasteners may attach to the wrong surface and cause surface damage.", "[0010] There has been previous attempts to create goggles having no leaks, shoes having replaceable outsoles, and apparel having more robust seams and zippers.", "Yet these efforts have produced sporting gear that suffers from either deficiencies in performance, comfort, or safety.", "[0011] There are adhesive systems in nature that have not been applied to sporting gear.", "For example, the adhesive system on the feet of some insects and lizards, such as Geckos, Anolis lizards, and skinks has attracted research interest.", "These organisms have been able to attach and detach their feet to climb smooth surfaces such as glass.", "The adhesion system involves the use of tiny slender natural protrusions known as setae (singular “seta”) attached to their feet.", "For example, a Tokay gecko lizard possesses seta having a diameter of five microns and a height of 110 microns.", "The seta may include a set of sub-protrusions which contact other surfaces and have even smaller dimensions.", "As these organisms climb up smooth surfaces such as glass, the setae help geckos form a temporary attachment so they do not slip and fall.", "Although aspects of a gecko-like adhesive system have been observed in nature, the technology has not yet been successfully applied to commercial products.", "[0012] Although foregoing research efforts have met with varying degrees of success, there remains an unresolved commercial need for more leak-proof swimming goggles, shoes with replaceable soles, and athletic apparel with more robust seams and zippers.", "SUMMARY OF THE INVENTION [0013] One aspect of the present invention may be to address and resolve the above limitations of conventional sporting gear.", "[0014] A man-made adhesive mechanism may be customized as part of sporting gear having a mounting surface that may be attached to a second surface.", "The adhesive mechanism may include a first plurality of nanofibers attached to the mounting surface.", "The first end of each nanofiber may be attached to the mounting surface using a flocking process along with the application of either thermal or radio frequency bonding.", "The second end of each of the first plurality of nanofibers may be placed in contact with the second surface not having nanofibers or a plurality of second nanofibers attached to the second surface to form a temporary attachment called nanoadhesion which may include a van der Waals force contribution.", "[0015] The nanoadhesion attachment may be detached by pulling the first plurality of nanofibers away at an angle from the second surface.", "Each nanofiber may include a fiber shaft less than 100 microns in length with a diameter of less than half a micron.", "[0016] In a first aspect, the present invention may be adapted to attach swimming goggles to the wearer's face.", "Goggles may include a lens component, also known as a lens cup, for each eye.", "A lens component may have a lens surface and a mounting surface.", "The mounting surface may be configured to form a seal with the skin around a wearer's eye.", "The mounting surface may be made of the same material as the lens surface or the mounting surface may be included as part of a lower modulus of elasticity material attached as part of the lens component.", "[0017] Nanofibers are attached to goggles at the mounting surfaces of each lens component and form a protrusion emanating from the mounting surface that contacts the skin around the wearer's eyes.", "The nanofibers may be attached around the entire perimeter or only in areas of the mounting surface that are prone to separate from the skin during use of the swimming goggles (such as to the right and left of the eye).", "The nanofibers may provide a nanoadhesion force to better keep the mounting surface attached to the skin during use and may easily be detached from the skin at the end of use by pulling the mounting surface away from the skin.", "[0018] In a second aspect, the present invention may be adapted to attach and detach components of an athletic shoe having an outsole, midsole assembly, and upper.", "The outsole contains a bottom surface to contact the ground and a top surface to contact the midsole assembly.", "The top surface of the outsole contains a first mounting surface with a first set of nanofibers attached.", "The midsole assembly may contain several components to provide shock absorption and stability such as a rear lower midsole, a directional cradle, and a primary midsole.", "A bottom surface of the midsole assembly may contain a second mounting surface having a second set of nanofibers attached.", "The outsole may be attached to the midsole assembly by bringing the first and second set of nanofibers together.", "[0019] Other sets of nanofibers and mounting surfaces may be included to attach the midsole assembly to the upper and/or the midsole components together.", "The attachment process allows worn components to be replaced and different components to be swapped out to provide several different shoe configurations for the same upper.", "The attachment process also improves manufacturing efficiency.", "[0020] The shoe assembly may include sunken surfaces and complementary three-dimensional shapes to define the mounting surfaces and to thereby assist in a mechanical interference to keep the outsole in place while the shoe may be used.", "Further the shoe may include seals and/or gaskets to keep contaminants such as dirt or water away from nanofibers.", "[0021] In yet a third aspect, the present invention may be adapted to create a nanofiber seam to attach woven panels to form various athletic gear such as shirts, jackets, shorts, pants, hats, socks, and/or shoes.", "Nanofibers may also be used to create attachments between garments, for example from a glove to a jacket or a coat to a pant, or a pant to a boot.", "[0022] An apparel item may be made up of various components (herein “panels”) that are attached at one or more seams.", "The panels are cut to the proper size.", "Panels may have nanofibers attached via the flocking process along an edge of each panel where a seam may be intended to join the panels.", "The nanofibers may be attached to one side or both sides of each of the edges.", "The panels are then attached by bringing the nanofibers in contact.", "The panels may also be folded over to allow additional nanofibers to come into contact and to be attached together.", "The nanofibers may be pulled apart to allow the panels to be orientated in a different position to each other.", "The seam may be supplemented by thread for strength.", "[0023] In yet a fourth aspect, the invention may be adapted to create a nanofiber-based zipper for athletic gear such as apparel, gym bags, footwear, and the like that contain panels as described above.", "The nanofiber zipper may be used to attach a first edge of a first panel with a second edge of a second panel.", "The first and second panels may have nanofibers attached via the flocking process along an edge of each panel where the nanofiber zipper may be intended to attach the panels.", "The nanofibers may be attached to one side of the first panel edge and to one side of the second panel edge.", "The panels are then attached by bringing the nanofibers in contact.", "The user may unzipper the nanofiber zipper by pulling the nanofibers apart at an angle through the use of a zipper slider that may be outfitted with a control handle.", "The nanofiber zipper may be supplemented by other fasteners such as traditional hooks or buttons.", "[0024] As should be apparent, the invention can provide a number of advantageous features and benefits.", "It is to be understood that, in practicing the invention, an embodiment can be constructed to include one or more features or benefits of embodiments disclosed herein, but not others.", "Accordingly, it is to be understood that the preferred embodiments discussed herein are provided as examples and are not to be construed as limiting, particularly since embodiments can be formed to practice the invention that do not include each of the features of the disclosed examples.", "BRIEF DESCRIPTION OF THE DRAWINGS [0025] A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: [0026] The invention will be better understood from reading the description which follows and from examining the accompanying figures.", "These are provided solely as non-limiting examples of the invention.", "In the drawings: [0027] FIG. 1 illustrates a nanofiber according to an embodiment of the present invention;", "[0028] FIGS. 2A-2E illustrate a process to attach the nanofiber to a mounting surface using an adhesive according to an embodiment of the present invention;", "[0029] FIGS. 3A-3E illustrate a process to attach the nanofiber to a mounting surface using heat or high frequency radio waves according to an embodiment of the present invention;", "[0030] FIG. 4A illustrates a pair of swimming goggles according to an embodiment of the present invention as viewed from the top;", "[0031] FIG. 4B illustrates the pair of swimming goggles according to an embodiment of the present invention as viewed from the front;", "[0032] FIG. 5A illustrates the swimming goggle according to an embodiment of the present invention as viewed from the back;", "[0033] FIG. 5B illustrates the swimming goggle according to an embodiment of the present invention as viewed from the top and including a close-up of nanofibers attached;", "[0034] FIG. 6A illustrates a swimming goggle according to an embodiment of the present invention without a head band as viewed from the back;", "[0035] FIG. 6B illustrates the swimming goggle according to an embodiment of the present invention without a head band as viewed from the top and including a close-up of nanofibers attached;", "[0036] FIG. 7A illustrates a ski goggle according to an embodiment of the present invention without a head band as viewed from the front;", "[0037] FIG. 7B illustrates the ski goggle according to an embodiment of the present invention without a head band as viewed from the top and including a close-up of nanofibers attached;", "[0038] FIG. 8A illustrates a set of skin areas or regions designed to be in contact with the swimming goggles according to an embodiment of the present invention as viewed from the front;", "[0039] FIG. 8B illustrates a skin area or region designed to be in contact with the ski goggle according to an embodiment of the present invention as viewed from the front;", "[0040] FIG. 9 illustrates a shoe having components attached by nanofibers according to an embodiment of the present invention as viewed from the side;", "[0041] FIG. 10 illustrates a lower from the shoe having components attached by nanofibers according to an embodiment of the present invention as viewed from the upper side;", "[0042] FIG. 11 illustrates a pair of mounting surfaces being attached by nanofibers connected to each of the mounting surfaces according to an embodiment of the present invention as viewed from the side;", "[0043] FIG. 12 illustrates an athletic garment having a seam and a zipper utilizing nanofibers according to an embodiment of the present invention as viewed from the front;", "[0044] FIG. 13A illustrates a set of two apparel panels having nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side;", "[0045] FIG. 13B illustrates the set of two apparel panels having nanofibers attached and folded according to an embodiment of the present invention as viewed from the side;", "[0046] FIG. 13C illustrates the set of two apparel panels having nanofibers attached, folded, and double-stitched with thread according to an embodiment of the present invention as viewed from the side;", "[0047] FIG. 14A illustrates a set of two apparel panels having double-sided and single-sided nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side;", "[0048] FIG. 14B illustrates the set of two apparel panels having double-sided and single-sided nanofibers attached according to an embodiment of the present invention as viewed from the side;", "[0049] FIG. 14C illustrates the set of two apparel panels having double-sided and single-sided nanofibers attached and double-stitched with thread according to an embodiment of the present invention as viewed from the side;", "[0050] FIG. 15A illustrates a set of two apparel panels having single-sided nanofibers prior to attachment according to an embodiment of the present invention as viewed from the side;", "[0051] FIG. 15B illustrates the set of two apparel panels having single-sided nanofibers attached according to an embodiment of the present invention as viewed from the side, this FIG. 15B also illustrates the preferred embodiment of the nanofiber zipper;", "[0052] FIG. 15C illustrates the set of two apparel panels having single-sided nanofibers attached and double-stitched with thread according to an embodiment of the present invention as viewed from the side;", "[0053] FIG. 16A illustrates first and second nanofiber folds as part of a nanofiber zipper detached in an open state as viewed from the top;", "[0054] FIG. 16B illustrates first and second nanofiber folds as part of the nanofiber zipper attached in a closed state as viewed from the top;", "[0055] FIG. 17A illustrates a cross section of an upper section of a nanozipper slider showing first and second nanofiber folds as viewed from the top;", "[0056] FIG. 17B illustrates a cross section of a lower section of the nanozipper slider showing first and second nanofiber folds as viewed from the top;", "[0057] FIG. 18A illustrates the nanofiber zipper slider from the front;", "[0058] FIG. 18B illustrates the nanofiber zipper slider from the left;", "[0059] FIG. 18C illustrates the nanofiber zipper slider as part of the full nanofiber zipper;", "[0060] FIG. 19A illustrates a nanofiber watch attached to a wrist using a strap as viewed from the side;", "[0061] FIG. 19B illustrates the nanofiber watch attached to a wrist without the strap as viewed from the side;", "[0062] FIG. 19C illustrates the nanofiber watch attached to a wrist without the strap as viewed from the top;", "[0063] FIG. 19D illustrates the nanofiber watch with nanofibers attached and the wrist as viewed from the side;", "[0064] FIG. 20A illustrates a second device attached to an arm using a strap as viewed from the front;", "[0065] FIG. 20B illustrates the second device watch attached to the arm without the strap as viewed from the front;", "[0066] FIG. 20C illustrates the second device as viewed from the front;", "[0067] FIG. 20D illustrates the second device with nanofibers attached and the arm as viewed from the side;", "[0068] FIG. 21A illustrates the second device attached directly to a piece of clothing using nanofibers as viewed from the front;", "[0069] FIG. 21B illustrates the second device as viewed from the front;", "[0070] FIG. 21C illustrates the second device with nanofibers attached and the piece of clothing as viewed from the side;", "and [0071] FIG. 21D illustrates the second device with nanofibers attached and the piece of clothing with nanofibers attached as viewed from the side.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0072] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.", "[0073] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.", "Wherever possible, the same reference characters will be used throughout the drawings to refer to the same or like parts.", "[0074] FIG. 1 illustrates an adhesive protrusion hereafter known as a nanofiber preferably having a length from 5 to 100 microns in length.", "The nanofiber diameter may be preferably 0.05 times its length which may range from 250 nanometers to a micron.", "A first terminal end 22 of a nanofiber shaft 23 may not be attached to a mounting surface.", "The opposite terminal end 24 of the nanofiber shaft may be attached to a mounting surface via an adhesive or other attachment method such as thermal or high frequency radiation induced bonding or the like.", "[0075] When the first terminal end 22 of the nanofiber 20 contacts another surface, attraction forces, including van der Waal forces, adhere the nanofiber end 22 to the other surface.", "The other surface may also have a second nanofiber attached by adhesive that adheres to the nanofiber and/or the mounting surface.", "The attraction forces produced by contact with the nanofiber is referred here as nanoadhesion.", "The resulting attraction forces mimic the action of setae on a gecko's foot.", "[0076] The nanofibers are constructed using various methods.", "These methods generally involve casting or molding the fibers, growing them in a solution, or deposition.", "One method may be to use lithography methods where a recess may be etched in a semiconductor substrate and nitride and oxide layers are deposited on the substrate.", "The surface then may be patterned and etched.", "When the underlying structure is etched, a stress difference between the oxide and nitride layers causes the structure to curl and to form a shaft structure.", "The ends 22 of the shaft may be roughened to increase surface area available for contact by using wet etching, radiation, plasma roughening, electrochemical etching and others.", "[0077] A preferred method of making nanofibers involves creating yarns of sub-micron diameter fibers.", "These yarns may be cut from the yarns to release the fibers in lengths such that when adhered to a mounting surface, in a position perpendicular to the mounting surface, the nanofiber will not collapse under its own weight.", "[0078] The nanofibers may be then collected and prepared for attachment to the mounting surface.", "The nanofibers may be cleaned to remove contaminants and then chemically treated to accept an electric charge.", "The nanofibers may be spin-dried and then oven-dried to a specific moisture content.", "Conductivity may depend on moisture content, so it may be preferable that some moisture remain with the nanofibers.", "The nanofibers 20 are then packaged in moisture-proof containers 4 to maintain optimal moisture until a later attachment of the nanofibers 20 to a mounting surface.", "[0079] The nanofibers 20 may then be attached to a mounting surface via a flocking process.", "There are various types of flocking methods available, but an electrostatic-based flocking method may be preferred for attaching nanofibers to a mounting surface because of its ability to better align the nanofibers to the mounting surface.", "[0080] Two electrostatic-based flocking processes are preferred for permanently attaching the nanofibers 20 to the mounting surface.", "The first process involves an adhesive to attach the nanofibers 20 to the mounting surface and the second process involves heat instead of the adhesive.", "[0081] In the first process shown in FIGS. 2A to 2E , the flocking process begins by applying a chemically-compatible adhesive to the mounting surface which has been properly cleaned.", "In the case of a textured mounting surface having peaks and valleys, the adhesive may only be applied to the peaks.", "Various adhesives may be used such as: a low viscosity ultra-violet cure epoxy, uncured silicone rubber, polyurethane resin, plastisol (polyvinyl chloride particles suspended in a plasticizer), or the like.", "[0082] As shown in FIG. 2B , the adhesive may be applied to the mounting surface in the area(s) where the nanofibers 20 are desired to be attached.", "The adhesive thickness applied may be dependent upon the adhesive used and the mounting surface.", "A statistical process control methodology may begin with a preferred adhesive thickness that may be approximately ten times the shaft diameter of the nanofiber.", "The thickness may then be adjusted to optimize the reliability of the adhesive to hold the nanofiber and the efficacy of the final product.", "[0083] This methodology will create a scaled fiber assembly substantially similar to that encountered in nature within the gecko's foot, and in a manner that lends itself to large scale industrial production.", "[0084] After the adhesive 3 may be applied, the mounting surface 2 may be placed between the flock hopper 5 and a grounded electrode 8 as shown in FIG. 2C .", "The flock hopper 5 may be filled with the many nanofibers transferred from the moisture-proof containers 4 .", "The flock hopper 5 may have rotating flock stirrers with a plurality of arms configured to allow the nanofibers 20 to become airborne randomly to produce a uniform pattern at the exit of the hopper.", "The airborne nanofibers may then pass through an electrode grid 6 at the exit of the flock hopper which imparts a charge on the airborne nanofibers 20 that is an opposite electric charge compared to the grounded electrode 8 .", "[0085] The temperature and humidity of the flocking environment may be critical in controlling the charge on the airborne nanofibers.", "Humidity too low may cause the nanofibers to not effectively take on an electrical charge and humidity too high may cause the nanofibers to undesirably stick or clump to each other.", "These humidity and temperature levels may be optimized according to the nanofiber characteristics and the adhesive used.", "[0086] Once the nanofibers 20 are electrically-charged and released from the flock hopper 5 to be airborne above the mounting surface as elements 7 , the nanofibers 7 will align themselves with the magnetic field between the electrodes 6 , 8 and accelerate towards an oppositely-charged electrode 8 arranged below the mounting surface 2 .", "The aligned and accelerated nanofibers 7 collide with and embed into the adhesive 3 in a position substantially perpendicular to the mounting surface 2 .", "[0087] Alternatively, the adhesive may be electrically charged instead of having a grounded electrode beneath the mounting surface.", "The nanofibers 20 would similarly embed into the adhesive 3 in the position substantially perpendicular to the mounting surface 2 .", "[0088] As shown in FIG. 2D , the mounting surface 2 may then be removed from between the flock hopper 5 area and excess nanofibers 21 which are not embedded into the adhesive 3 may be removed via vacuum 9 or other suction device.", "The adhesive 3 may be allowed to cure and the nanofibers 20 remain attached and generally perpendicular to the mounting surface as shown in FIG. 2E .", "[0089] The second process may be shown in FIGS. 3A to 3E .", "The nanofibers 20 used in this process may be made of thermoplastic which may form a bond with the mounting surface 2 greater than a certain temperature.", "Various thermoplastics may be used such as Poly(methyl methacrylate) or PMMA, polyethylene (PE), Polystyrene (PS), or the like.", "[0090] As represented in FIG. 3A , the mounting surface 2 may first be prepared for the attachment of the nanofibers 20 by cleaning using surfactants or other cleaning agents available to remove contaminants that may inhibit the subsequent process steps.", "Next, as shown in FIG. 3B , the mounting surface 2 may be heated.", "The heater 10 may be an oven, a frequency radiation emitter, or the like.", "The heater 10 may use heating means 11 such as radiation heat transfer or convention heat transfer to heat the mounting surface 2 to a temperature above the melting point of the material used to make the nanofibers 20 .", "For example, the melting point of PMMA is approximately 135 degrees Celsius, polyethylene is between 105 to 130 degrees Celsius, and polystyrene melts at roughly 240 degrees Celsius.", "[0091] After heating, the mounting surface 2 may be placed between the flock hopper 5 and a grounded electrode 8 as shown in FIG. 3C .", "The flock hopper 5 may be filled with the many nanofibers transferred from the moisture-proof containers 4 .", "The flock hopper 5 converts the nanofibers 20 into airborne nanofibers 7 which then pass through an electrode grid 6 at the exit of the flock hopper to impart a charge on the airborne nanofibers 20 that is an opposite electrical charge compared to that of the grounded electrode 8 .", "[0092] Once the airborne nanofibers 7 are electrically-charged and released from the flock hopper 5 to be airborne above the mounting surface, they will align themselves with the magnetic field between the electrodes 6 , 8 and accelerate towards an oppositely-charged electrode 8 arranged below the substrate 2 .", "The aligned and accelerated nanofibers 7 collide with the heated mounting surface 2 and nanofibers 7 partially melt at the contact point between the nanofibers 20 and the heated mounting surface 2 to form a permanent attachment point.", "[0093] The mounting surface 2 may then be removed from between the flock hopper 5 area and the excess nanofibers 21 that are not attached to the mounting surface 2 are removed via vacuum 9 or other suction device as shown in FIG. 3D .", "The mounting surface 2 may be allowed to cool and the nanofibers 20 remain attached and generally perpendicular to the mounting surface as illustrated in FIG. 3E .", "First Embodiment—Nanofiber Swimming Goggles [0094] Sporting gear provides useful applications for nanoadhesion.", "In the first embodiment, swim goggles are commonly used to enable swimmers to keep water out of their eyes.", "The swim goggles 101 are illustrated in FIGS. 4A to 7B .", "The swim goggles 101 may include two eye components 102 , a nose bridge 108 and a head band 104 .", "The nose bridge 108 may be designed to hold each of the eye components 102 a fixed distance apart.", "The head band 104 may fit around the head of the wearer and be attached at each end to the eye components 102 .", "Each eye component 102 may include a lens surface 103 , a connector interface 107 , a head band interface 105 , and a sealant surface 106 .", "The connector interface 107 may connect the nose bridge 108 to the eye component 102 .", "The head band interface 105 may connect the head band 104 to the eye component 102 .", "The sealant surface 106 may contact a skin contact area 123 , 124 of the left or right eye 121 , 122 as shown in FIG. 8A .", "The shape of the sealant surface 106 may be similar to the shape of the skin area 123 , 124 to allow contact all around the eye 121 , 122 .", "The sealant surface 106 may be the same material as the lens surface 103 .", "[0095] As shown in FIG. 5B , the sealant surface 106 may have many nanofibers 20 attached at the terminal end 24 .", "The unattached terminal ends 22 of the nanofibers 20 are configured to contact the skin contact area 123 , 124 when the goggles 101 are worn by a user and thereby form a nanoadhesion attachment with the skin contact area 123 , 124 .", "[0096] The nanofibers 20 are not configured to penetrate the skin contact area 123 which is composed of several skin layers including the epidermis and dermis.", "The human epidermis is the outer skin layer and its minimum thickness is 50 microns at the eyelids.", "The human epidermis has five sub-layers and the cells divide at the inner layers and are gradually pushed to the exterior layers where their cells flatten and die to be shed every two weeks.", "The nanofibers 20 may be configured to merely contact the outer layers of the epidermis to avoid skin injury.", "[0097] Another embodiment of the goggles may have a rubber gasket.", "The rubber gasket may act as the sealant surface 106 and may be merely attached to the eye component 102 via adhesive such as epoxy cement or the like.", "The gasket 106 may be made from rubber, silicone, or other soft material.", "One end 24 of each nanofiber 20 may be permanently attached to the rubber gasket 106 using one of the flocking processes 1 , 12 .", "The skin contact area 123 , 124 contacts the unattached end 22 of the nanofibers 20 when the swim goggles 101 are worn and a nanoadhesion attachment may be made between the nanofiber 20 and the skin contact area 123 , 124 .", "[0098] Embodiments of the goggles 101 are intended to be used by the wearer in a similar way.", "The wearer places the eye components 102 , 109 over the eyes 121 , 122 , so that the end 22 of the nanofibers 20 attached to the sealant surface 106 contacts the skin contact area 123 .", "The wearer then fastens the head band 104 around the wearer's head to provide a comfortable fit which pulls the sealant surface 106 against the skin 123 in order to form a watertight seal.", "The wearer may also slightly depress the eye component 102 against the skin 123 to force a small amount of air to be pushed out from between the eye compartment 102 and the eye 121 .", "When this air is pushed out, the watertight seal keeps the air from returning and thereby maintains a negative suction between the eye component 102 and the corresponding eye 121 to improve the watertight seal.", "The negative suction is an absolute pressure less than ambient pressure.", "The user may also depress the eye component 109 to achieve a similar negative suction to improve the watertight seal related to the other eye 122 .", "[0099] As the wearer engages in a water activity involving immersing the user's head and swim goggles 101 in water, the watertight seal may be maintained because the skin 123 remains in contact with the sealant surface 106 as a result of the negative suction, the pull of the head band 104 , and the nanoadhesion attraction between the nanofibers 20 and the skin 123 .", "This watertight seal may be more robust than goggles without nanofibers 20 , because as the wearer engages in vigorous activities while wearing the goggles 101 the tight seal may be vulnerable to compromise as the contact skin area 123 changes shape relative to the sealant surface 106 during the water activity.", "[0100] When the water activity has been completed, the wearer merely releases the head band 104 from the back of the wearer's head and the wearer pulls the eye components 102 , 109 from the skin contact areas 123 , 124 .", "[0101] A second aspect to this first embodiment may be swim goggles without a head band 104 , connector interface 107 , and nose bridge 108 as shown in FIGS. 5A and 5B .", "In this second aspect, each eye component 102 is identical to each other and has nanofibers 20 attached to the sealant surface 106 .", "Just prior to the wearer engaging in a water activity involving immersing the user's head and swim goggles in water, an eye component is placed in contact with each of the respective skin areas 123 , 124 so that the nanofibers 20 are in contact with the respective skin areas 123 , 124 .", "A watertight seal may be maintained as described with respect to a single eye component because the skin 123 remains in contact with the sealant surface 106 as a result of negative suction and the nanoadhesion attraction between the nanofibers 20 and the skin 123 .", "When the water activity has been completed, the wearer merely pulls each eye component from the respective skin areas 123 , 124 .", "[0102] As shown in FIGS. 7A and 7B , ski goggles may be a second aspect of this first embodiment.", "The ski goggles 130 may include a lens 131 and a sealant surface 132 .", "The ski goggles 130 may or may not also include a strap (strap not shown).", "The sealant surface 132 has nanofibers 20 attached using at least one of the flocking processes mentioned earlier.", "Just prior to the wearer engaging in a skiing activity, the nanofibers 20 are placed in contact with a skin area 125 as shown in FIG. 8B .", "A nanoadhesion attraction between the skin area 125 and the nanofibers 20 is created which keeps the ski goggles 130 attached to the skin area 125 .", "When the skiing activity has been completed, the wearer merely pulls the sealant surface 132 away from the skin area 125 .", "Other sports goggles, prescription or non-prescription, are also embodied in this application and can be similarly constructed.", "[0103] In yet another embodiment, the sealant surface 132 having nanofibers 20 may be located instead on a waistband or shirt cuff to grip the nearby skin better.", "Second Embodiment—Replaceable Shoe Components [0104] Another embodiment utilizing the nanofibers 20 is illustrated in FIG. 9 as an athletic shoe 200 having an upper 201 and a lower 202 .", "FIG. 10 shows the lower 202 for a left foot, but the right shoe has a similar construction.", "The lower 202 may include a full-length primary midsole 210 , a directional cradle 211 , a first cushion 212 , a second cushion 213 , a third cushion 214 , a rear lower midsole 215 , a rear outsole 220 , a lateral outsole 221 , a medial outsole 222 , a center outsole 223 , and a front outsole 224 .", "The directional cradle 211 may be attached to the primary midsole 210 .", "The cushions 212 , 213 , 214 may be attached to both the directional cradle 211 and the rear lower midsole 215 .", "The components of the outsole 220 , 221 , 222 , 223 , 224 may be attached to the rear lower midsole 215 , directional cradle 211 , and/or primary midsole 210 .", "Any of the components that are part of the lower 202 may be attached together where as shown in FIG. 11 a first set of nanofibers 241 are permanently attached to first mounting surface 240 and a second set of nanofibers 231 are permanently attached to a second mounting surface 230 via the flocking processes 1 , 12 .", "The mounting surfaces 230 , 240 may be part of the components of the lower 202 .", "Then, using the process of nanoadhesion, the first and second nanofibers 231 , 241 are placed in contact as the components of the lower 202 are placed in contact to form a nanoadhesion attachment.", "The attachment may be temporary because the user may pull the lower components (elements 210 - 215 and/or 220 to 224 ) apart to remove or replace the component with a second component.", "[0105] The nanoadhesion embodiments of shoe 200 are intended to be used by the wearer in a similar way.", "The wearer inserts her foot into the upper 201 and fastens the upper 201 comfortably to the foot so the foot may be disposed between the upper 201 and the lower 202 .", "The wearer may engage in whatever activity desired so that the outsole components 220 , 221 , 222 , 223 , 224 may have a set of impacts with the ground.", "[0106] When the activity has been completed, the upper 201 may be unfastened and the wearer's foot removed from the shoe 200 .", "When one or more of the components of the lower 202 become worn beyond repair and need to be replaced, then the wearer will pull the set of nanofibers 231 permanently attached to the worn component from the set of nanofibers 241 attached to another component.", "Next, the wearer may attach a replacement component having a new set of nanofibers 231 on a mounting surface 230 to the old corresponding set of nanofibers 241 on the other component by bringing them in contact.", "Third Embodiment—Nanofiber Seams [0107] Yet another embodiment may be to produce a nanofiber seam to connect woven panels as part of athletic gear such as shirts, jackets, shorts, pants, hats, socks, and/or shoes.", "Various seam configurations may be created with nanofibers.", "For example, FIG. 12 illustrates an athletic shirt 300 having a first woven panel 310 and a second woven panel 320 attached by a nanofiber seam 301 .", "[0108] The woven panels 310 , 320 may first be cut to the proper size prior to being attached by the seam 301 .", "The woven panel 310 has a top side 312 and a bottom side 313 as shown in FIG. 13A .", "The woven panel 320 has a top side 322 and a bottom side 323 .", "The panels 310 , 320 may have nanofibers 231 , 241 attached via the flocking process 1 , 12 along an edge of each panel where a seam may be intended to join the panels.", "The nanofibers 231 may be attached to one side of the panel 310 at a panel edge 311 as shown by FIG. 13A .", "The nanofibers 241 may be permanently attached to one side of the panel 320 at a panel edge 321 using the flocking process 1 , 12 .", "The panels 310 , 320 are then attached by bringing the nanofibers 231 , 241 in contact at the panel edges 311 , 321 .", "FIG. 13B shows the attached panel edges 311 , 321 after being folded over.", "FIG. 13C shows thread stitches 302 , 303 added to add strength and to form a nanofiber seam 304 .", "Prior to the stitching 302 , 303 being applied, the nanofibers 231 , 241 may be pulled apart to allow the panels 310 , 320 to be reattached in case they have been incorrectly positioned together the first time.", "[0109] In yet an alternative embodiment, the nanofibers 231 , 241 may be attached to the panels 310 , 320 in both single-sided 412 , 422 and double-sided 411 , 421 nanofiber areas as shown in FIG. 14A .", "In this embodiment two of the double-sided nanofiber areas 411 , 421 are first placed in contact, then folded over to allow the remaining two double-sided nanofiber areas 411 , 421 to attach to the single-sided nanofiber areas 412 , 422 as shown in FIG. 14B .", "Threaded stitching 402 , 403 may be added for strength and to form a second nanofiber seam 404 as shown in FIG. 14C .", "[0110] In another embodiment, a nanofiber seam 504 may be produced by attaching nanofibers to panels, 310 , 320 to form a set of single-sided nanofiber areas 511 , 521 as shown in FIG. 15A .", "The nanofiber panel edges 511 , 521 are attached together using nanoadhesion by being placed in contact as shown in FIG. 15B .", "Stitching 502 , 503 is applied to add further strength to the nanofibers and thereby produce the nanofiber seam 504 as shown in FIG. 15C .", "[0111] The nanofiber seams 304 , 404 , 504 , may be used by apparel designers to construct various athletic gear products from one or more woven panels.", "When the athletic gear is utilized by the final user, the nanofiber seam should keep one or more woven panels reliably together.", "[0112] In yet another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to reconfigure a pocket on clothing so that the location and the shape of the space that can be accommodated within the pocket may be changed by adjusting the contact area between the panel edges 511 and 521 at a perimeter of the pocket and clothing that the pocket is mounted upon.", "[0113] In a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to connect a jacket to pants, e.g., sporting apparel such as running jackets and pants, warm-up jackets and pants, and/or ski jackets and pants.", "This may improve warmth by keeping the wind out of the area between the jacket and the pants.", "The panel edge 511 may be on the bottom of the jacket edge and the panel edge 521 may be on the top of the pants as shown in the FIG. 15A .", "When the pants are attached to the jacket at the panel edges 511 , 521 , then the panels may create the nanoadhesion attachment as shown in FIG. 15B .", "[0114] In yet a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to connect cuff-tabs on shirt sleeves to eliminate the need for buttons.", "[0115] In another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to adjust the size of air vents in clothing so that the user may decide to enlarge vents during strenuous activity and then reduce the size of the vents after the activity has finished.", "[0116] In a further embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to attach and detach removable clothing elements, such as hoods and sleeves.", "[0117] In yet another embodiment, the seam arrangement represented by the nanofiber panel edges 511 , 521 may be used to attach and detach packaging components so the packaging closure may be curved instead of straight.", "Fourth Embodiment—Nanofiber Zipper [0118] Yet another embodiment that may utilize the nanofibers 20 in sporting gear is a nanofiber zipper 600 , as shown in the athletic shirt 300 shown earlier in FIG. 12 .", "The zipper may also be adapted for use in athletic gear such as apparel, gym bags, footwear, and the like.", "[0119] The nanofiber zipper 600 may be illustrated in FIGS. 12, 16A, 16B and 18C where the nanofiber zipper may be configured to detach a first panel edge 606 from a second panel edge 616 ( FIG. 16A ) and then later reattach the panels 606 , 616 ( FIG. 16B ).", "The first panel 606 includes both a top side 607 and a bottom side 608 .", "The second panel 616 includes both a top side 617 and a bottom side 618 .", "The nanofiber zipper 600 may include a zipper slider 630 configured to open and close the zipper, a first nanofiber fold 602 as part of first panel edge 606 , a first set of nanofibers 603 attached as part of first panel edge 606 , a second nanofiber fold 612 as part of second panel edge 616 , and a second set of nanofibers 613 attached as part of second panel edge 616 .", "The nanofiber zipper 600 may include a first set of thread stitches 604 , 605 to add strength to the first nanofiber fold 602 and a second set of thread stitches 614 , 615 to add strength to the second nanofiber fold 612 .", "The first nanofiber fold 602 may include a top fold side 620 and a bottom fold side 621 .", "The second nanofiber 612 fold may include a top side 622 and a bottom side 623 .", "[0120] The first and second nanofiber folds 602 , 612 as well as the first and second nanofibers 603 , 613 may be created and attached using the same concepts already discussed as part of the processes used to make the nanofiber seams 304 , 404 , 504 .", "[0121] FIGS. 16B and 17B show the nanofiber zipper 600 in the closed state where the nanofibers on the first nanofiber fold 602 have attached to the second set of nanofibers 613 using nanoadhesion.", "Also, the nanofibers on the second nanofiber fold 612 have attached to the first set of nanofibers 603 using nanoadhesion.", "[0122] The zipper slider 630 opens and closes the zipper 600 and includes a control handle (not shown) for the user to control the zipper 600 .", "The control handle may be attached at an attachment point 650 as shown in FIGS. 18A, 18B, and 18C .", "[0123] FIGS. 17A and 18A show a cross section at the top 651 of the zipper slider 630 where the panel edges 606 , 616 are unattached to each other.", "The first and second nanofiber folds 602 , 612 are used to guide the panel edges 606 , 616 through the zipper slider 630 .", "FIG. 17B shows a cross section at the bottom 652 of the zipper slider 630 where the panel edges 606 , 616 are attached via nanoadhesion.", "[0124] A close-up of the zipper slider 630 is shown at FIG. 18A .", "The slider top 651 is wider than the slider bottom 652 .", "FIG. 18B shows the left side of the zipper slider 630 with an open groove 652 for the first panel edge 606 to travel.", "[0125] The nanofiber zipper 600 may be supplemented by other fasteners such as traditional hooks or buttons.", "[0126] The nanofiber zipper 600 is operated by the user by grabbing a control handle (not shown) attached to the 650 attachment at the zipper slider 630 .", "The user moves the zipper slider 630 up 700 along the length of the panel edges 606 , 616 to close the zipper 600 .", "The user may open the zipper 600 by moving the zipper slider 630 down 701 along the length of the panel edge 606 , 616 and the nanofibers on the panel edges 606 , 616 may be pulled apart by the zipper slider.", "The process is reversible and the zipper 600 may be opened and closed many times.", "[0127] Although various zipper embodiments are possible with nanoadhesion, the preferred embodiment is shown in FIGS. 15A-15B .", "The preferred zipper includes panels 310 , 320 with nanofibers attached at nanofiber panel edges 511 , 512 .", "The nanofiber panel edges 511 , 521 are attached together using nanoadhesion by being placed in contact as shown in FIG. 15B .", "The nanofibers panel edges 511 , 512 may be later detached by pulling them apart.", "Fifth Embodiment—Device Attachment [0128] Yet another embodiment that may utilize the nanofibers 20 in sporting gear is a nanofiber attachment, as demonstrated by a wristwatch 800 in FIG. 19A .", "The nanofiber attachment may be adapted for other devices other than wristwatches, for example, global positioning system devices, music players or video entertainment devices, communication devices, heart rate monitors, biometric sensors, and the like.", "[0129] The nanofiber watch 800 may include a strap 801 while worn on the wrist 126 or may be attached to the wrist 126 directly using nanofibers 20 as shown in FIGS. 19B-19D .", "The watch 800 includes nanofibers 20 that may be attached using one or more of the flocking processes 1 , 12 discussed earlier.", "The watch 800 may be attached directly to the wrist 126 by placing the nanofibers 20 in contact with the 126 or arm 127 to form a nanoadhesion attachment.", "The wearer engages in whatever activities desired and the nanoadhesion attachment keeps the watch 800 attached to the wrist 126 .", "When the watch 800 is to be removed from the wrist 126 , then the wearer may pull the watch 800 away from the wrist 126 to separate the nanofibers 20 from the wrist 126 .", "[0130] A second aspect to the device attachment is to attach a second device 810 to the arm 127 as shown in FIG. 20A-20D .", "The second device may be a time measuring device, heart monitor, location device, music or video entertainment device, medical sensor, athletic performance measuring sensor, communication device, or the like.", "The second device 810 may include a strap 811 while worn on the arm 127 or may be attached to the arm 127 directly while solely using nanofibers 20 .", "The second device includes nanofibers 20 that may be attached using one or more of the flocking processes 1 , 12 discussed earlier.", "The second device 810 may be attached directly to the arm 127 by placing the nanofibers 20 in contact with the arm 127 to form a nanoadhesion attachment.", "The wearer engages in whatever activities desired and the nanoadhesion attachment keeps the second device 810 attached to the arm 127 .", "When the second device 810 is to be removed from the arm 127 , then the wearer may pull the second device 810 away from the arm 127 to separate the nanofibers 20 from the arm 127 as shown in FIG. 20D .", "[0131] In a third aspect to the device attachment embodiment, a second device 810 is attached to a piece of clothing 812 as shown in FIGS. 21A-21C .", "The second device 810 may be attached directly to the clothing 812 .", "The user merely attaches the second device 810 to the clothing 812 so that the nanofibers 20 on the device 810 come in contact with the clothing 812 to form a nanoadhesion attachment.", "When the second device 810 is to be removed from the clothing 812 , then the wearer may pull the second device 810 away from the clothing 812 to separate the nanofibers 20 from the clothing 812 as shown in FIG. 21C .", "The piece of clothing 812 may be shirts, pants, socks, shoes, jackets, or the like.", "[0132] In yet a fourth aspect to the device attachment embodiment, the second device 810 is attached to a piece of clothing 812 having nanofibers 815 attached to the clothing 812 .", "In this aspect a nanoadhesion attachment is formed between the nanofibers 20 attached to the second device 810 and the nanofibers 815 attached to the clothing 812 using the one or more of the flocking processes described earlier.", "The user merely attaches the second device 810 to the clothing 812 so that the nanofibers 20 on the device 810 and the nanofibers 815 on the clothing 812 come in contact with each other to form a nanoadhesion attachment.", "The user engages in whatever activity is desired and the nanoadhesion attachment keeps the device 810 attached to the clothing 812 .", "When the second device 810 is to be removed from the clothing 812 , then the wearer may pull the second device 810 away from the clothing 812 to separate the nanofibers 20 , 815 as shown in FIG. 21D .", "[0133] In yet a fifth aspect to the device attachment embodiment, the second device 810 illustrated in either FIGS. 21C or 21D could be a component designed to cushion the impact of certain body parts during sporting activities.", "The component could be functionally equivalent to shin pads used by soccer players, modular protection zones used by football players on football pants and other protective gear, or localized padding used in biking shorts used by cyclists to lessen the shock and bumps from a bicycle seat to contact points on the human body.", "The component may have nanofibers 20 attached to the component and may have nanofibers 815 attached to the contact area on the clothing.", "[0134] In yet a sixth aspect to the device attachment embodiment, the second device 810 may be a backpack and a set of associated straps that may be attached to a wearer's clothing using nanofibers 20 attached to the associated straps.", "The nanofibers 20 may be attached to nanofibers 815 on the wearer's clothing to form a nanoadhesion attachment.", "An advantage of using nanofibers 20 , 815 to attach the straps to the clothing may be to reduce chafing during activity.", "Other embodiments may have a backpack without straps and the backpack attached directly to the clothing with a nanoadhesion attachment.", "[0135] In a seventh embodiment, a bottle closure (broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with a bottle (broadly represented as element 812 in FIG. 21C ) to replace threaded closures used on bottles, such as soda cans, water bottles, and the like.", "[0136] In an eighth embodiment, a roof rack may to interface with an automobile (the roof rack broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with an exterior surface of an automobile (broadly represented as element 812 in FIG. 21C ).", "The roof rack may be used to transport bicycles, boats, sporting equipment, packages in transit, or the like.", "[0137] In a ninth embodiment, a clothing hanger (the hanger is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with clothing that is desired to be hung from the hanger (the clothing broadly represented as element 812 in FIG. 21C ).", "The clothing may or may not have nanofibers to attach with those nanofibers 20 on the hanger.", "[0138] In a tenth embodiment, a clothing price tag or information tag (the tag is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with clothing that the tag is associated with (the clothing broadly represented as element 812 in FIG. 21C ).", "[0139] In an eleventh embodiment, a portion of a surface of a glove (the portion of the glove surface is broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with an item that the glove is gripping while the glove is in the user's hand (the item is broadly represented as element 812 in FIG. 21C ).", "The item may be a basketball, water polo ball, a hockey stick, a tennis racquet, or other item similarly to be gripped by a glove.", "[0140] In a twelfth embodiment, a gripping surface (the gripping surface broadly represented as element 810 in FIG. 21C ) may have nanofibers 20 to form a nanoadhesion attachment with a surface of a hand or glove (the surface of the hand or glove broadly represented as element 812 in FIG. 21C ).", "The gripping surface may be a hockey stick gripping area, a tennis racquet grip, or other surface similarly gripped by a glove or hand.", "The glove may also have nanofibers 20 attached to interface with the nanofibers on the gripping surface.", "[0141] Further, it should be appreciated that the exemplary embodiments of the invention are not limited to the exemplary embodiments shown and described above.", "While this invention has been described in conjunction with exemplary embodiments outlined above, various alternatives, modifications, variations and/or improvements, whether known or that are, or may be, presently unforeseen, may become apparent.", "Accordingly, the exemplary embodiments of the invention, as set forth above are intended to be illustrative, not limiting.", "The various changes may be made without departing from the spirit and scope of the invention.", "Therefore, the systems and methods according to exemplary embodiments of this invention are intended to embrace all now known or later-developed alternatives, modifications, variations and/or improvements.", "[0142] Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings.", "It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein." ]
FIELD OF THE INVENTION [0001] The present invention relates generally to elongated working platforms and in particular to an elevating platform assembly of the type having a rack and pinion drive mechanism. BACKGROUND OF THE INVENTION [0002] Elongated working platforms are well known in the art and are commonly used during construction to support workers and equipment at desired elevations. Platforms of this nature include stationary scaffolding as well as moveable elevating platform assemblies. Although stationary scaffolding is useful, in many instances it is desired to change quickly the elevation of workers and equipment and thus, elevating platform assemblies are advantageous. [0003] One known type of elevating platform assembly is manufactured by Hydro Mobile of L'Assomption, Quebec. This elevating platform assembly includes an elevating platform that is supported at one end by a mast. A drive mechanism acts between the elevating platform and the mast. The drive mechanism includes a trolley moveable along the mast to which the platform is secured. A motor is mounted on the trolley and drives pinions that cooperate with a rack secured to the mast. In this manner, the elevating platform can be moved upwardly and downwardly along the mast. [0004] Although this elevating platform assembly works satisfactorily, when heavy loads are placed on the elevating platform near its end furthest from the mast, significant torque can be applied to the trolley by the elevating platform. The torque applied to the trolley acts to pull the trolley away from the mast. If the trolley moves relative to the mast under the influence of the torque, misalignment between the teeth of the pinions and the teeth of the rack results. This of course can result in stripping of the pinions as the trolley is advanced along the mast. As will be appreciated improvements to elevating platform assemblies of this nature are desired. [0005] It is therefore an object of the present invention to provide a novel elevating platform assembly of the type having a rack and pinion drive mechanism. SUMMARY OF THE INVENTION [0006] According to one aspect of the present invention there is provided an elevating platform assembly comprising: [0007] a generally vertical mast having a generally vertical rack mounted thereon; [0008] a first trolley coupled to said mast and being moveable therealong; [0009] a drive mechanism carried by said first trolley, said drive mechanism including at least one pinion in mating engagement with said rack; and [0010] an elongated elevating platform extending from said mast and having a second trolley mounted adjacent one end thereof, said second trolley coupling said elevating platform to said mast and being moveable along said mast, wherein said first trolley is coupled to at least one of said second trolley and said elevating platform in a manner to maintain alignment of said at least one pinion and rack when loads are placed on said elevating platform that create moments at said mast. [0011] In one embodiment, the first trolley is coupled to the elevating platform via a shock absorbing arrangement that includes an elastomeric element. The shock absorbing arrangement permits the elevating platform to pivot relative to the first trolley without significant forces being applied to the first trolley that act to pull the first trolley away from the mast. [0012] In another embodiment, the first trolley is positioned on the mast below the second trolley and is coupled to the second trolley through shock absorbing elements carried by at least one of the first and second trolleys. [0013] According to another aspect of the present invention there is provided an elevating platform assembly comprising: [0014] an upright mast having a vertical rack extending along at least one side thereof; [0015] a motor trolley coupled to said mast, said motor trolley carrying a drive mechanism including at least one rotatable pinion in mating engagement with said rack, rotation of said at least one pinion advancing said motor trolley vertically along said mast; [0016] an elongated elevating platform extending from said at least one side of said mast, said elevating platform including a generally horizontal work surface; and [0017] a main trolley acting between said elevating platform and said mast and being moveable vertically along said mast, wherein said motor trolley is coupled to one of said main trolley and said elevating platform in a manner so as to maintain alignment of said at least one pinion and said rack when loads are placed on said elevating platform. [0018] The present invention provides advantages in that the coupling between the first trolley and either the second trolley or the elevating platform inhibits the at least one pinion from becoming misaligned with the rack when loads are placed on the elevating platform that create moments at the mast. By maintaining the at least one pinion and rack in alignment regardless of loads placed on the elevating platform, the likelihood of stripping of the teeth on the at least one pinion is reduced. BRIEF DESCRIPTION OF THE DRAWINGS [0019] Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which: [0020] [0020]FIG. 1 is an isometric view of an elevating platform assembly in accordance with the present invention; [0021] [0021]FIG. 2 is an isometric view of a portion of the elevating platform assembly of FIG. 1 showing a motor trolley, main trolley and elevating platform arrangement; [0022] [0022]FIG. 3 is an isometric view of a portion of FIG. 2 showing the coupling between the motor trolley and the elevating platform; [0023] [0023]FIG. 4 is a side elevational view of FIG. 2; and [0024] [0024]FIG. 5 is an isometric view of another embodiment of a motor trolley, main trolley and elevating platform arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0025] Referring now to FIG. 1, an elevating platform assembly is shown and is generally identified by reference numeral 10 . As can be seen, elevating platform assembly 10 includes a generally vertical mast 12 that is supported by a base assembly 14 resting on a ground surface. An elongate elevating platform 16 extends from one side of the mast 12 generally at a right angle. The elevating platform 16 includes a generally planar work surface 20 secured to an underlying supporting framework 22 . Guard rails 24 surround the work surface 20 . The elevating platform 16 is coupled to the mast 12 in a manner that permits the elevating platform to move vertically along the mast 12 thereby to allow the work surface 20 to be positioned at desired elevations as will be described. [0026] The mast 12 is formed from a series of stacked, box-type mast sections 30 , one of which is shown in FIG. 2. As can be seen, mast 12 includes four vertical corner rails 32 joined by horizontal crossbars 34 at vertically spaced locations. A plurality of diagonal cross-members 36 extends between the rails 32 and the horizontal crossbars 34 to provide additional support to the mast 12 . A vertical rack 40 is secured to the horizontal crossbars 34 on one side of the mast 12 by suitable fasteners 42 . [0027] A main trolley 50 is coupled to the mast 12 and runs along the rails 32 that are on opposite sides of the rack 40 . The main trolley 50 includes a generally rectangular frame structure 52 . Each side of the frame structure 52 is constituted by a pair of vertical side members 54 and 56 joined together by a series of steps 58 . Upper and lower cross members 60 and 62 span the sides of the frame structure 52 . A roller set support 64 is positioned at each corner of the frame structure 52 and extends inwardly towards the mast 12 . Three sets of rollers 68 are mounted on each support 64 . The rollers 68 on the supports 64 surround and engage the rails 32 . [0028] The main trolley 50 is secured to the framework 22 of the elevating platform 16 by upper and lower angles 72 and 74 respectively on opposite sides of the main trolley 50 . Specifically, the upper angles 72 secure the main trolley 50 to a main upper beam 76 that supports the work surface 20 . The lower angles 74 secure the main trolley 50 to a main lower beam 78 . Since the elevating platform 16 is fixed to the main trolley 50 , the elevating platform and the main trolley 50 move as a unit. [0029] Nested within the main trolley 50 is a motor trolley 100 (best illustrated in FIG. 3). As can be seen, the motor trolley 100 includes a generally rectangular frame structure 102 including a pair of vertical side members 104 joined at their upper and lower ends by supporting plates 106 . A horizontal member 108 spans the side members 104 intermediate the supporting plates 106 . A roller set support 109 is positioned at each corner of the frame structure 102 and extends inwardly towards the mast 12 . A set of rollers 111 is mounted on each support 109 . The rollers 111 on the supports 109 surround and engage the rails 32 . [0030] A drive mechanism 110 is mounted on each supporting plate 106 . Each drive mechanism 110 includes a motor 112 having an output shaft 114 . Shaft 114 extends through a bushing on the supporting plate 106 and has a gear 116 keyed to its other end. Gear 106 engages a pair of vertically spaced pinions 118 that are in mating engagement with the rack 40 . Rotation of the shafts 114 by the motors 112 imparts rotation of the pinions 118 via the gears 116 . This of course allows the motor trolley 100 to advance along the rack 40 and hence, along the mast 12 . [0031] A shock absorbing arrangement acts between the framework 22 of the elevating platform 16 and the motor trolley 100 to provide a floating couple therebetween. As can be seen, the shock absorbing arrangement includes a C-shaped member 120 having a web 122 and upper and lower limbs 124 and 126 defining a channel therebetween. The web 122 is welded to the main upper beam 76 of the framework 22 . An elastomeric shock absorbing element 128 is secured to the upper limb 124 and is positioned within the channel. The cross member 108 of the motor trolley 100 is accommodated within the channel and forms an interference fit with the elastomeric shock absorbing element 128 and the lower limb 126 . [0032] In operation, when the motors 112 are actuated to rotate the shafts 114 and hence the gears 116 , the rotation of the gears 116 imparts rotation of the pinions 118 . Since the pinions 118 are in mating engagement with the rack 40 , as the pinions 118 rotate, the pinions 118 advance along the rack 40 causing the motor trolley 100 to move along the mast 12 . The direction in which the motor trolley 100 advances along the mast 12 of course depends on the direction the shafts 114 are rotated. As mentioned above, the framework 22 of the elevating platform 16 is coupled to the motor trolley 100 via the shock absorbing arrangement. Therefore, the elevating platform 16 moves with the motor trolley 100 as a unit. [0033] During use, the elevating platform 16 may be heavily loaded. If the load is positioned on the elevating platform 16 away from the mast 12 , the loading on the elevating platform 16 may create a significant moment at the point of connection between the elevating platform and the mast 12 . As the elevating platform 16 pivots under the load and the lower limb 126 of the C-shaped member 120 pushes against the cross member 108 , the cross member 108 contacts the shock absorbing element 128 . The shock absorbing element 128 in turn deforms allowing the elevating platform to pivot relative to the motor trolley 100 . In this manner, significant forces that act to pull the motor trolley 100 away from the mast 12 are not imparted on the motor trolley 100 by the elevating platform. Thus, the pinions 118 and rack 140 remain in alignment despite the loads placed on the elevating platform 16 . [0034] Turning now to FIG. 5, an alternative motor trolley and main trolley arrangement for the elevating platform assembly 10 is shown. In this embodiment, the configurations of the motor trolley 100 and the main trolley 50 are the same as those described with reference to the first embodiment; however, the two trolleys are not nested. Instead, the motor trolley 100 is positioned below both the main trolley 50 and the elevating platform 16 with the main trolley 50 resting on the motor trolley 100 . Elastomeric elements 150 are mounted on the top roller set supports 109 of the motor trolley 100 and act between the motor trolley 100 and the main trolley 50 . Since the motor trolley 100 and the elevating platform 16 are not coupled directly, moments at the mast 12 that are caused by loads placed on the elevating platform 16 are not transferred to the motor trolley 100 . As a result, the pinions 118 and rack 40 remain in alignment regardless of the loads placed on the elevating platform 16 . [0035] As will be appreciated, by avoiding a fixed rigid connection between the motor trolley 100 and the elevating platform 16 , significant moments resulting from loading of the elevating platform 16 are not transferred to the motor trolley 100 . This of course maintains the rack 40 and pinions 118 in alignment reducing the likelihood of stripping of the pinions. [0036] Although the elevating platform assembly is shown having a single elevating platform extending from one side the mast, those of skill in the art will appreciate that the elevating platform assembly may include an additional elevating platform extending from the opposite side of the mast. The second elevating platform may be coupled to the first elevating platform and driven by the drive mechanism of the first elevating platform or may include its own motor trolley and drive mechanism. In this latter case, a second rack is provided on the mast 12 . [0037] Although preferred embodiments of the present invention have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.
An elevating platform assembly includes a generally vertical mast having a generally vertical rack mounted thereon. A first trolley is coupled to the mast and is moveable therealong. A drive mechanism is carried by the first trolley and includes at least one pinion in mating engagement with the rack. An elongated elevating platform extends from the mast and has a second trolley mounted adjacent one end thereof. The second trolley couples the elevating platform to the mast and is moveable along the mast. The first trolley is coupled to at least one of the second trolley and elevating platform in a manner to maintain alignment of the at least one pinion and rack when loads are placed on the elevating platform that create moments at the mast.
Concisely explain the essential features and purpose of the invention.
[ "FIELD OF THE INVENTION [0001] The present invention relates generally to elongated working platforms and in particular to an elevating platform assembly of the type having a rack and pinion drive mechanism.", "BACKGROUND OF THE INVENTION [0002] Elongated working platforms are well known in the art and are commonly used during construction to support workers and equipment at desired elevations.", "Platforms of this nature include stationary scaffolding as well as moveable elevating platform assemblies.", "Although stationary scaffolding is useful, in many instances it is desired to change quickly the elevation of workers and equipment and thus, elevating platform assemblies are advantageous.", "[0003] One known type of elevating platform assembly is manufactured by Hydro Mobile of L'Assomption, Quebec.", "This elevating platform assembly includes an elevating platform that is supported at one end by a mast.", "A drive mechanism acts between the elevating platform and the mast.", "The drive mechanism includes a trolley moveable along the mast to which the platform is secured.", "A motor is mounted on the trolley and drives pinions that cooperate with a rack secured to the mast.", "In this manner, the elevating platform can be moved upwardly and downwardly along the mast.", "[0004] Although this elevating platform assembly works satisfactorily, when heavy loads are placed on the elevating platform near its end furthest from the mast, significant torque can be applied to the trolley by the elevating platform.", "The torque applied to the trolley acts to pull the trolley away from the mast.", "If the trolley moves relative to the mast under the influence of the torque, misalignment between the teeth of the pinions and the teeth of the rack results.", "This of course can result in stripping of the pinions as the trolley is advanced along the mast.", "As will be appreciated improvements to elevating platform assemblies of this nature are desired.", "[0005] It is therefore an object of the present invention to provide a novel elevating platform assembly of the type having a rack and pinion drive mechanism.", "SUMMARY OF THE INVENTION [0006] According to one aspect of the present invention there is provided an elevating platform assembly comprising: [0007] a generally vertical mast having a generally vertical rack mounted thereon;", "[0008] a first trolley coupled to said mast and being moveable therealong;", "[0009] a drive mechanism carried by said first trolley, said drive mechanism including at least one pinion in mating engagement with said rack;", "and [0010] an elongated elevating platform extending from said mast and having a second trolley mounted adjacent one end thereof, said second trolley coupling said elevating platform to said mast and being moveable along said mast, wherein said first trolley is coupled to at least one of said second trolley and said elevating platform in a manner to maintain alignment of said at least one pinion and rack when loads are placed on said elevating platform that create moments at said mast.", "[0011] In one embodiment, the first trolley is coupled to the elevating platform via a shock absorbing arrangement that includes an elastomeric element.", "The shock absorbing arrangement permits the elevating platform to pivot relative to the first trolley without significant forces being applied to the first trolley that act to pull the first trolley away from the mast.", "[0012] In another embodiment, the first trolley is positioned on the mast below the second trolley and is coupled to the second trolley through shock absorbing elements carried by at least one of the first and second trolleys.", "[0013] According to another aspect of the present invention there is provided an elevating platform assembly comprising: [0014] an upright mast having a vertical rack extending along at least one side thereof;", "[0015] a motor trolley coupled to said mast, said motor trolley carrying a drive mechanism including at least one rotatable pinion in mating engagement with said rack, rotation of said at least one pinion advancing said motor trolley vertically along said mast;", "[0016] an elongated elevating platform extending from said at least one side of said mast, said elevating platform including a generally horizontal work surface;", "and [0017] a main trolley acting between said elevating platform and said mast and being moveable vertically along said mast, wherein said motor trolley is coupled to one of said main trolley and said elevating platform in a manner so as to maintain alignment of said at least one pinion and said rack when loads are placed on said elevating platform.", "[0018] The present invention provides advantages in that the coupling between the first trolley and either the second trolley or the elevating platform inhibits the at least one pinion from becoming misaligned with the rack when loads are placed on the elevating platform that create moments at the mast.", "By maintaining the at least one pinion and rack in alignment regardless of loads placed on the elevating platform, the likelihood of stripping of the teeth on the at least one pinion is reduced.", "BRIEF DESCRIPTION OF THE DRAWINGS [0019] Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which: [0020] [0020 ]FIG. 1 is an isometric view of an elevating platform assembly in accordance with the present invention;", "[0021] [0021 ]FIG. 2 is an isometric view of a portion of the elevating platform assembly of FIG. 1 showing a motor trolley, main trolley and elevating platform arrangement;", "[0022] [0022 ]FIG. 3 is an isometric view of a portion of FIG. 2 showing the coupling between the motor trolley and the elevating platform;", "[0023] [0023 ]FIG. 4 is a side elevational view of FIG. 2;", "and [0024] [0024 ]FIG. 5 is an isometric view of another embodiment of a motor trolley, main trolley and elevating platform arrangement.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0025] Referring now to FIG. 1, an elevating platform assembly is shown and is generally identified by reference numeral 10 .", "As can be seen, elevating platform assembly 10 includes a generally vertical mast 12 that is supported by a base assembly 14 resting on a ground surface.", "An elongate elevating platform 16 extends from one side of the mast 12 generally at a right angle.", "The elevating platform 16 includes a generally planar work surface 20 secured to an underlying supporting framework 22 .", "Guard rails 24 surround the work surface 20 .", "The elevating platform 16 is coupled to the mast 12 in a manner that permits the elevating platform to move vertically along the mast 12 thereby to allow the work surface 20 to be positioned at desired elevations as will be described.", "[0026] The mast 12 is formed from a series of stacked, box-type mast sections 30 , one of which is shown in FIG. 2. As can be seen, mast 12 includes four vertical corner rails 32 joined by horizontal crossbars 34 at vertically spaced locations.", "A plurality of diagonal cross-members 36 extends between the rails 32 and the horizontal crossbars 34 to provide additional support to the mast 12 .", "A vertical rack 40 is secured to the horizontal crossbars 34 on one side of the mast 12 by suitable fasteners 42 .", "[0027] A main trolley 50 is coupled to the mast 12 and runs along the rails 32 that are on opposite sides of the rack 40 .", "The main trolley 50 includes a generally rectangular frame structure 52 .", "Each side of the frame structure 52 is constituted by a pair of vertical side members 54 and 56 joined together by a series of steps 58 .", "Upper and lower cross members 60 and 62 span the sides of the frame structure 52 .", "A roller set support 64 is positioned at each corner of the frame structure 52 and extends inwardly towards the mast 12 .", "Three sets of rollers 68 are mounted on each support 64 .", "The rollers 68 on the supports 64 surround and engage the rails 32 .", "[0028] The main trolley 50 is secured to the framework 22 of the elevating platform 16 by upper and lower angles 72 and 74 respectively on opposite sides of the main trolley 50 .", "Specifically, the upper angles 72 secure the main trolley 50 to a main upper beam 76 that supports the work surface 20 .", "The lower angles 74 secure the main trolley 50 to a main lower beam 78 .", "Since the elevating platform 16 is fixed to the main trolley 50 , the elevating platform and the main trolley 50 move as a unit.", "[0029] Nested within the main trolley 50 is a motor trolley 100 (best illustrated in FIG. 3).", "As can be seen, the motor trolley 100 includes a generally rectangular frame structure 102 including a pair of vertical side members 104 joined at their upper and lower ends by supporting plates 106 .", "A horizontal member 108 spans the side members 104 intermediate the supporting plates 106 .", "A roller set support 109 is positioned at each corner of the frame structure 102 and extends inwardly towards the mast 12 .", "A set of rollers 111 is mounted on each support 109 .", "The rollers 111 on the supports 109 surround and engage the rails 32 .", "[0030] A drive mechanism 110 is mounted on each supporting plate 106 .", "Each drive mechanism 110 includes a motor 112 having an output shaft 114 .", "Shaft 114 extends through a bushing on the supporting plate 106 and has a gear 116 keyed to its other end.", "Gear 106 engages a pair of vertically spaced pinions 118 that are in mating engagement with the rack 40 .", "Rotation of the shafts 114 by the motors 112 imparts rotation of the pinions 118 via the gears 116 .", "This of course allows the motor trolley 100 to advance along the rack 40 and hence, along the mast 12 .", "[0031] A shock absorbing arrangement acts between the framework 22 of the elevating platform 16 and the motor trolley 100 to provide a floating couple therebetween.", "As can be seen, the shock absorbing arrangement includes a C-shaped member 120 having a web 122 and upper and lower limbs 124 and 126 defining a channel therebetween.", "The web 122 is welded to the main upper beam 76 of the framework 22 .", "An elastomeric shock absorbing element 128 is secured to the upper limb 124 and is positioned within the channel.", "The cross member 108 of the motor trolley 100 is accommodated within the channel and forms an interference fit with the elastomeric shock absorbing element 128 and the lower limb 126 .", "[0032] In operation, when the motors 112 are actuated to rotate the shafts 114 and hence the gears 116 , the rotation of the gears 116 imparts rotation of the pinions 118 .", "Since the pinions 118 are in mating engagement with the rack 40 , as the pinions 118 rotate, the pinions 118 advance along the rack 40 causing the motor trolley 100 to move along the mast 12 .", "The direction in which the motor trolley 100 advances along the mast 12 of course depends on the direction the shafts 114 are rotated.", "As mentioned above, the framework 22 of the elevating platform 16 is coupled to the motor trolley 100 via the shock absorbing arrangement.", "Therefore, the elevating platform 16 moves with the motor trolley 100 as a unit.", "[0033] During use, the elevating platform 16 may be heavily loaded.", "If the load is positioned on the elevating platform 16 away from the mast 12 , the loading on the elevating platform 16 may create a significant moment at the point of connection between the elevating platform and the mast 12 .", "As the elevating platform 16 pivots under the load and the lower limb 126 of the C-shaped member 120 pushes against the cross member 108 , the cross member 108 contacts the shock absorbing element 128 .", "The shock absorbing element 128 in turn deforms allowing the elevating platform to pivot relative to the motor trolley 100 .", "In this manner, significant forces that act to pull the motor trolley 100 away from the mast 12 are not imparted on the motor trolley 100 by the elevating platform.", "Thus, the pinions 118 and rack 140 remain in alignment despite the loads placed on the elevating platform 16 .", "[0034] Turning now to FIG. 5, an alternative motor trolley and main trolley arrangement for the elevating platform assembly 10 is shown.", "In this embodiment, the configurations of the motor trolley 100 and the main trolley 50 are the same as those described with reference to the first embodiment;", "however, the two trolleys are not nested.", "Instead, the motor trolley 100 is positioned below both the main trolley 50 and the elevating platform 16 with the main trolley 50 resting on the motor trolley 100 .", "Elastomeric elements 150 are mounted on the top roller set supports 109 of the motor trolley 100 and act between the motor trolley 100 and the main trolley 50 .", "Since the motor trolley 100 and the elevating platform 16 are not coupled directly, moments at the mast 12 that are caused by loads placed on the elevating platform 16 are not transferred to the motor trolley 100 .", "As a result, the pinions 118 and rack 40 remain in alignment regardless of the loads placed on the elevating platform 16 .", "[0035] As will be appreciated, by avoiding a fixed rigid connection between the motor trolley 100 and the elevating platform 16 , significant moments resulting from loading of the elevating platform 16 are not transferred to the motor trolley 100 .", "This of course maintains the rack 40 and pinions 118 in alignment reducing the likelihood of stripping of the pinions.", "[0036] Although the elevating platform assembly is shown having a single elevating platform extending from one side the mast, those of skill in the art will appreciate that the elevating platform assembly may include an additional elevating platform extending from the opposite side of the mast.", "The second elevating platform may be coupled to the first elevating platform and driven by the drive mechanism of the first elevating platform or may include its own motor trolley and drive mechanism.", "In this latter case, a second rack is provided on the mast 12 .", "[0037] Although preferred embodiments of the present invention have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims." ]
CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to provisional application 60/771,593, filed Feb. 8, 2006. FIELD OF THE INVENTION This invention relates in general to oil and gas well drilling and in particular to a method of completing a horizontal well that enables a wireline well tool to be pumped down a liner. BACKGROUND OF THE INVENTION Highly deviated or horizontal wells are commonly drilled for oil and gas production. As used herein, the term “horizontal” refers to not only wells with truly horizontal sections, but also to wells that are highly deviated. In one type of horizontal well completion, the operator installs and cements a casing or liner that extends to the total depth of the well. Normally, the term “casing” refers to conduit that extends back to the surface wellhead, and “liner” refers to conduit that has its upper end supported near the lower end of a first string of casing. These terms will be used interchangeably herein to refer to a conduit in a well that is cemented in place, whether its upper end extends to the surface or just to the lower end of a first string of casing. After cementing the casing, the operator perforates through the casing into the producing formation. The operator may then perform other operations, such as hydraulic fracturing or dispensing acid or other chemicals into the producing formation. Normally, the operator installs a string of production tubing in the casing for the production flow. Even though wells may be fairly close to each other, producing formations often vary in characteristics from one well to another, such as thickness, depth, porosity, water content, permeability and the like. Consequently, it is useful to have a survey or log made of the well before it is cased to provide the characteristics of the producing formation. In highly deviated and horizontal wells, logging can be made while drilling using measuring while drilling techniques. After cementing, it is also useful for the operator to perform another survey of the well. Because of the casing, the cased-hole log differs from an open-hole survey. By using tools such as ones that measure natural gamma rays emitted by earth formations, the operator will be able to discern the same formations previously noted during the open-hole survey. The operator uses this information to determine precisely where to perforate. Even without an open-hole log, a cased-hole survey provides important information to the operator. In a vertical or even a moderately deviated well, the operator can run a cased-hole log before perforating by lowering a surveying instrument on a wireline into the casing and making the survey either while running-in or retrieving. Logging a cased horizontal well presents a problem, because gravity won't pull the tool down. One approach has been to mount to the instrument a tractor with motor-driven wheels or tracks. Generally, these logging procedures are expensive and slow. Also, high voltages are typically required, which can be detrimental to the wireline. Surveying instruments have been pumped down wells in the prior art. An annular piston is mounted to the instrument assembly for sealingly engaging the conduit. This type of operation requires a flow path for displaced fluid below the piston as the instrument moves downward. In the prior art, the flow path typically comprises an open annulus surrounding the conduit containing the instrument. In a cased horizontal well, there is no open annulus surrounding the casing and no place for displaced fluid. Consequently, pump-down logging is normally not performed on horizontal wells. SUMMARY In this invention, the operator runs and cements a conduit, such as a liner or casing in a wellbore. The operator then forms one or more displacement perforations through the conduit and surrounding cement and into an earth formation. He then pumps down a wireline logging tool with a pump-down head. The downward movement of the pump-down head causes some of the fluid below the pump-down head to be displaced out through the displacement perforation into the formation. While the logging tool is in the conduit, the operator performs a survey of the well. Preferably, the operator forms the displacement perforation with a firing head assembly comprising a sealed chamber containing a piston, a firing pin, and an impact detonator. The firing head assembly is mounted within a sub and the impact detonator is linked to a perforating charge. The operator secures the sub to the string of conduit as it is being lowered into the wellbore. After cementing, the operator lowers a drill bit into the conduit and drills out cement left in the sub and in the lower portion of the conduit. The drill bit ruptures the sealed chamber of the firing head assembly, which exposes the sealed chamber to drilling fluid pressure. The fluid pressure causes the piston to drive the firing pin against the detonator, thereby detonating the perforating charge. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view illustrating a well with a liner having a displacement sub in accordance with this invention, the liner being shown after cementing but before displacement perforations have been made. FIG. 2 is an enlarged sectional view of the displacement sub of FIG. 1 , shown removed from the liner. FIG. 3 is a further enlarged sectional view of the firing head assembly of the displacement sub of FIG. 2 . FIG. 4 is a sectional view of the displacement sub of FIG. 1 , taken along the line 4 - 4 of FIG. 2 , and shown prior to cementing. FIG. 5 is a sectional view of the displacement sub of FIG. 1 , taken along the line 4 - 4 of FIG. 2 , and shown after cementing. FIG. 6 is a sectional view similar to FIG. 1 , but showing a drill string drilling through the interior of the displacement sub after cementing. FIG. 7 is an enlarged sectional view of the displacement sub as shown in FIG. 6 , after it has been drilled through and the displacement perforations made. FIG. 8 is a sectional view of the displacement sub as shown in FIG. 7 , taken along the line 8 - 8 of FIG. 7 . FIG. 9 is a sectional view of a logging instrument being pumped down the liner of FIG. 1 . FIG. 10 is a sectional view of the well of FIG. 1 after final perforating and installation of production tubing. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 , the well has a vertical section with a conventional string of casing 11 that is cemented in place. The operator has drilled an open hole section 13 below casing 11 open hole section 13 having a substantially horizontal portion that may extend thousands of feet. In the embodiment of FIG. 1 , a string of drill pipe 15 is shown extending into the casing 11 . A setting tool 17 is located on the lower end of drill pipe 15 . Setting tool 17 is connected to a tieback extension 19 , which in turn is connected to a packer 21 . Packer 21 is connected to a liner hanger 23 . A liner 25 is secured to liner hanger 23 for securing the upper end of liner 25 to the inner diameter of casing 11 . Liner 25 is a string of casing smaller in diameter than the casing 11 . Rather than having its upper end near the lower end of casing 11 , liner 25 could have its upper end at the surface. Liner 25 is shown in the process of being installed with its upper end a short distance above the lower end of casing 11 and its lower end near the bottom of the well. Setting tool 17 , tieback extension 19 , packer 21 and hanger 23 are conventional components used to set liner 25 . Liner 25 has a landing collar 27 at its lower end for receiving a conventional cement plug (not shown). A displacement sub 29 constructed in accordance with this invention is secured to the lower end of landing collar 27 . An extension member 31 , which may be a section of the same pipe as liner 25 , extends below displacement sub 29 . A conventional cement set shoe 33 is secured to the lower end of extension member 31 . After running liner 25 , the operator pumps cement down liner 25 , landing collar 27 , displacement sub 29 , extension member 31 and cement shoe 33 . Cement 35 flows out cement shoe 33 and back up the annulus in open hole 13 surrounding liner 25 , as illustrated in FIG. 1 . After dispensing the desired amount of cement, the operator pumps down a conventional drillable plug (not shown), which lands in landing collar 27 . Cement 35 will cure not only in the annulus surrounding landing collar 27 , extension member 31 , displacement sub 29 , and liner 25 , but also within extension member 31 and displacement sub 29 . Immediately after pumping cement 35 , the operator sets packer 21 and retrieves the string of drill pipe 15 and setting tool 17 . Referring to FIG. 2 , displacement sub 29 has a tubular steel housing 37 of substantially the same diameter as liner 25 . Housing 37 contains a body 39 of a drillable material, such as aluminum, brass or composite. Body 39 is a cylindrical member that is sealingly secured within housing 37 . Body 39 has a flow port 41 extending from its upper end to its lower end for fluid circulation prior to cementing and also for cement 35 flow. As shown in FIG. 4 , flow port 41 may be crescent-shaped, and it is offset from the longitudinal axis of body 39 . Prior to pumping the cement through displacement sub 29 , flow port 41 is open. As shown in FIG. 5 , after pumping cement 35 , the cement will cure within and block flow port 41 . Referring to FIG. 3 , a firing head assembly 43 is secured by threads into the upper end of body 39 . Firing head assembly 43 is also of drillable materials and is offset from the axis of body 39 . Firing head assembly 43 has a housing 45 made up of a number of tubular sections secured and sealed together as shown in FIG. 3 . A bore 47 is located within an upper portion of firing head housing 45 . Firing head housing 45 has a cap 49 that encloses the upper end of bore 47 . A piston 51 is carried within bore 47 for movement from the initial position shown in FIG. 3 to a lower position (not shown). Piston 51 is initially spaced with its upper end below cap 49 . A chamber 53 at atmospheric pressure is located between the upper end of piston 51 and cap 49 . Piston 51 sealingly engages bore 47 and is held in the initial position by shear pins 55 . Piston 51 has a downward extending rod with a sharp firing pin 57 fixed to its lower end. A percussive detonator 59 is located within firing head housing 45 a short distance below firing pin 57 . Detonator 59 is connected to detonating cord 61 , which leads to one or more shaped or perforating charges 63 (only one shown in FIGS. 2 and 3 ). Detonator 59 , detonating cord 61 and shaped charges 63 are conventional components used in perforating operations. The number of shaped charges 63 can vary. Referring to FIG. 2 , an optional dye pack housing 65 is secured by threads to the lower end of body 39 . Dye pack housing 65 is also of drillable material and has a sealed chamber that contains a dye. When exposed to well bore fluid, the dye will discolor the fluid circulating back to the surface to indicate that displacement sub 29 has been drilled through. Referring to FIG. 6 , after cement 35 is cured and the operator has removed setting tool 17 ( FIG. 1 ), the operator runs back into the well with a drill bit 67 on the lower end of drill pipe 15 . Drill bit 67 will drill the cement plug (not shown) in collar 27 , and then began drilling components of displacement sub 29 . During drilling, the operator pumps drilling fluid through drill pipe 15 , which discharges from drill bit 67 and flows back up the annulus between drill pipe 15 and liner 25 . Once drill bit 67 drills through cap 49 ( FIG. 3 ), the pressure of the drilling fluid will be applied to chamber 53 , which was previously at atmospheric pressure. The drilling fluid pressure causes shear pins 55 to shear, pushing piston 51 and firing pin 57 downward. Firing pin 57 strikes and ignites detonator 59 , which in turn ignites detonating cord 61 and shaped charges 63 . The explosion creates perforations 69 through cement 35 and into the earth formation as illustrated in FIGS. 7 and 8 . After firing, the operator continues drilling firing head assembly 43 ( FIG. 3 ) and body 39 ( FIG. 2 ). When drill bit 67 reaches dye pack assembly 65 , the dye is released. The fluid being pumped down drill string 15 causes dye 66 to color the drilling fluid returning to the surface, indicating to the operator that he has now drilled through displacement sub 29 . Tile operator stops drilling substantially at this point, leaving cement 35 within extension member 31 and cement shoe 33 . The operator then retrieves drill pipe 15 and drill bit 67 ( FIG. 6 ). Referring to FIG. 9 , the operator may now perform wireline services in the well, using a wireline tool 73 . Wireline tool 73 may be any type of conventional wireline service equipment, such as a gamma ray wireline tool, a cement bond wireline tool, perforating equipment or a plug or packer setting tool. Wireline tool 73 may be attached to a pump-down head 71 to facilitate pumping down liner 25 . Pump-down head 71 is piston-like member that fits closely within tile inner diameter of liner 25 . Because of their large diameter, some wireline tools 73 , such as a bridge plug, may not need an additional pump down head 71 . Pump down head 71 is located at the lower end of wireline tool 73 , which is connected to an electrical cable 77 that leads to the surface. At the surface, a blowout preventer 79 will close the well in the event of an emergency. Blowout preventer 79 may include wireline rams that close around electrical cable 77 as well as shear rams that will cut it. A manifold 81 is secured to blowout preventer 79 for pumping fluid, typically water, into casing 11 and liner 25 to force pump-down head 71 downward. A lubricator 83 seals around electrical cable 77 as it moves. Electrical cable 77 is dispensed by a winch 85 at the surface. A logging unit 87 supplies electrical power to electrical cable 77 and receives signals indicating parameters of the earth formations and cement 35 . As illustrated in FIG. 9 , fluid 89 is located below pump-down head 71 . As pump-down head 71 moves downward, it displaces some of the fluid 89 , which flows into displacement perforations 69 . The exterior of pump-down head 71 does not form a tight seal with the inner diameter of liner 25 ; rather a small clearance will exist for some of the fluid 89 to flow around pump-down head 71 as it moves downward. However, without displacement perforations 69 , it would not be feasible to pump wireline tool 73 to the lower end of liner 25 . Preferably, the operator continues pumping down pump-down head 71 until it reaches the lower end of displacement sub 29 . Subsequently, the operator will retrieve pump-down head 71 and tool 73 by winding electrical cable 77 back onto winch 85 . The operator may perform the log while retrieving tool 73 , or while pumping tool 73 down, or both. The operator then may complete the well by running production tubing and perforating in a variety of conventional manners. Referring to FIG. 10 , in one completion method, the operator perforates to form production perforations 93 above displacement perforations 69 . The production perforations 93 could be made in several ways, one of which could be pumping down through liner 25 a pump-down perforating gun on wireline, with displaced fluid flowing out displacement perforations 69 . A bridge plug 91 could then be set above the displacement perforations 69 to isolate them from production perforations. The operator may then run a string of production tubing 95 and set a packer 97 in liner 25 above production perforations 93 . Tubing 95 is suspended conventionally from a wellhead assembly 99 for conveying well fluid to the surface. Alternately, the operator could first set bridge plug 91 , then run tubing 95 , then pump down a perforating gun through tubing 95 with displaced fluid flowing back up the tubing annulus within liner 25 before setting packer 97 . The operator could also make the production perforations with a tubing conveyed perforating gun. The invention has significant advantages. By forming a displacement perforation into the formation, the operator can use a pump-down logging tool, with displacement fluid flowing into the formation. Forming the displacement perforation while drilling out the cement avoids an additional trip just to make the displacement perforation. This method avoids the need for a tractor, thus saving time and expense. While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention.
A firing head assembly has a sealed chamber containing a piston, a firing pin, and an impact detonator. The firing head assembly and a perforating charge are installed within a sub and the sub is secured into a string of conduit being lowered into a wellbore. After cementing the conduit, the operator drills out the cement in the conduit, disintegrating the chamber and exposing the sealed chamber to the fluid pressure of the drilling fluid in the conduit. The drilling fluid pressure causes the piston to drive the firing pin against the detonator, which detonates the perforating charge. The operator then pumps down a logging tool to survey the well. Fluid in the conduit below the pump-down head can flow out the displacement perforation into the earth formation while the logging tool is moving downward.
Summarize the patent information, clearly outlining the technical challenges and proposed solutions.
[ "CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to provisional application 60/771,593, filed Feb. 8, 2006.", "FIELD OF THE INVENTION This invention relates in general to oil and gas well drilling and in particular to a method of completing a horizontal well that enables a wireline well tool to be pumped down a liner.", "BACKGROUND OF THE INVENTION Highly deviated or horizontal wells are commonly drilled for oil and gas production.", "As used herein, the term “horizontal”", "refers to not only wells with truly horizontal sections, but also to wells that are highly deviated.", "In one type of horizontal well completion, the operator installs and cements a casing or liner that extends to the total depth of the well.", "Normally, the term “casing”", "refers to conduit that extends back to the surface wellhead, and “liner”", "refers to conduit that has its upper end supported near the lower end of a first string of casing.", "These terms will be used interchangeably herein to refer to a conduit in a well that is cemented in place, whether its upper end extends to the surface or just to the lower end of a first string of casing.", "After cementing the casing, the operator perforates through the casing into the producing formation.", "The operator may then perform other operations, such as hydraulic fracturing or dispensing acid or other chemicals into the producing formation.", "Normally, the operator installs a string of production tubing in the casing for the production flow.", "Even though wells may be fairly close to each other, producing formations often vary in characteristics from one well to another, such as thickness, depth, porosity, water content, permeability and the like.", "Consequently, it is useful to have a survey or log made of the well before it is cased to provide the characteristics of the producing formation.", "In highly deviated and horizontal wells, logging can be made while drilling using measuring while drilling techniques.", "After cementing, it is also useful for the operator to perform another survey of the well.", "Because of the casing, the cased-hole log differs from an open-hole survey.", "By using tools such as ones that measure natural gamma rays emitted by earth formations, the operator will be able to discern the same formations previously noted during the open-hole survey.", "The operator uses this information to determine precisely where to perforate.", "Even without an open-hole log, a cased-hole survey provides important information to the operator.", "In a vertical or even a moderately deviated well, the operator can run a cased-hole log before perforating by lowering a surveying instrument on a wireline into the casing and making the survey either while running-in or retrieving.", "Logging a cased horizontal well presents a problem, because gravity won't pull the tool down.", "One approach has been to mount to the instrument a tractor with motor-driven wheels or tracks.", "Generally, these logging procedures are expensive and slow.", "Also, high voltages are typically required, which can be detrimental to the wireline.", "Surveying instruments have been pumped down wells in the prior art.", "An annular piston is mounted to the instrument assembly for sealingly engaging the conduit.", "This type of operation requires a flow path for displaced fluid below the piston as the instrument moves downward.", "In the prior art, the flow path typically comprises an open annulus surrounding the conduit containing the instrument.", "In a cased horizontal well, there is no open annulus surrounding the casing and no place for displaced fluid.", "Consequently, pump-down logging is normally not performed on horizontal wells.", "SUMMARY In this invention, the operator runs and cements a conduit, such as a liner or casing in a wellbore.", "The operator then forms one or more displacement perforations through the conduit and surrounding cement and into an earth formation.", "He then pumps down a wireline logging tool with a pump-down head.", "The downward movement of the pump-down head causes some of the fluid below the pump-down head to be displaced out through the displacement perforation into the formation.", "While the logging tool is in the conduit, the operator performs a survey of the well.", "Preferably, the operator forms the displacement perforation with a firing head assembly comprising a sealed chamber containing a piston, a firing pin, and an impact detonator.", "The firing head assembly is mounted within a sub and the impact detonator is linked to a perforating charge.", "The operator secures the sub to the string of conduit as it is being lowered into the wellbore.", "After cementing, the operator lowers a drill bit into the conduit and drills out cement left in the sub and in the lower portion of the conduit.", "The drill bit ruptures the sealed chamber of the firing head assembly, which exposes the sealed chamber to drilling fluid pressure.", "The fluid pressure causes the piston to drive the firing pin against the detonator, thereby detonating the perforating charge.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view illustrating a well with a liner having a displacement sub in accordance with this invention, the liner being shown after cementing but before displacement perforations have been made.", "FIG. 2 is an enlarged sectional view of the displacement sub of FIG. 1 , shown removed from the liner.", "FIG. 3 is a further enlarged sectional view of the firing head assembly of the displacement sub of FIG. 2 .", "FIG. 4 is a sectional view of the displacement sub of FIG. 1 , taken along the line 4 - 4 of FIG. 2 , and shown prior to cementing.", "FIG. 5 is a sectional view of the displacement sub of FIG. 1 , taken along the line 4 - 4 of FIG. 2 , and shown after cementing.", "FIG. 6 is a sectional view similar to FIG. 1 , but showing a drill string drilling through the interior of the displacement sub after cementing.", "FIG. 7 is an enlarged sectional view of the displacement sub as shown in FIG. 6 , after it has been drilled through and the displacement perforations made.", "FIG. 8 is a sectional view of the displacement sub as shown in FIG. 7 , taken along the line 8 - 8 of FIG. 7 .", "FIG. 9 is a sectional view of a logging instrument being pumped down the liner of FIG. 1 .", "FIG. 10 is a sectional view of the well of FIG. 1 after final perforating and installation of production tubing.", "DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 , the well has a vertical section with a conventional string of casing 11 that is cemented in place.", "The operator has drilled an open hole section 13 below casing 11 open hole section 13 having a substantially horizontal portion that may extend thousands of feet.", "In the embodiment of FIG. 1 , a string of drill pipe 15 is shown extending into the casing 11 .", "A setting tool 17 is located on the lower end of drill pipe 15 .", "Setting tool 17 is connected to a tieback extension 19 , which in turn is connected to a packer 21 .", "Packer 21 is connected to a liner hanger 23 .", "A liner 25 is secured to liner hanger 23 for securing the upper end of liner 25 to the inner diameter of casing 11 .", "Liner 25 is a string of casing smaller in diameter than the casing 11 .", "Rather than having its upper end near the lower end of casing 11 , liner 25 could have its upper end at the surface.", "Liner 25 is shown in the process of being installed with its upper end a short distance above the lower end of casing 11 and its lower end near the bottom of the well.", "Setting tool 17 , tieback extension 19 , packer 21 and hanger 23 are conventional components used to set liner 25 .", "Liner 25 has a landing collar 27 at its lower end for receiving a conventional cement plug (not shown).", "A displacement sub 29 constructed in accordance with this invention is secured to the lower end of landing collar 27 .", "An extension member 31 , which may be a section of the same pipe as liner 25 , extends below displacement sub 29 .", "A conventional cement set shoe 33 is secured to the lower end of extension member 31 .", "After running liner 25 , the operator pumps cement down liner 25 , landing collar 27 , displacement sub 29 , extension member 31 and cement shoe 33 .", "Cement 35 flows out cement shoe 33 and back up the annulus in open hole 13 surrounding liner 25 , as illustrated in FIG. 1 .", "After dispensing the desired amount of cement, the operator pumps down a conventional drillable plug (not shown), which lands in landing collar 27 .", "Cement 35 will cure not only in the annulus surrounding landing collar 27 , extension member 31 , displacement sub 29 , and liner 25 , but also within extension member 31 and displacement sub 29 .", "Immediately after pumping cement 35 , the operator sets packer 21 and retrieves the string of drill pipe 15 and setting tool 17 .", "Referring to FIG. 2 , displacement sub 29 has a tubular steel housing 37 of substantially the same diameter as liner 25 .", "Housing 37 contains a body 39 of a drillable material, such as aluminum, brass or composite.", "Body 39 is a cylindrical member that is sealingly secured within housing 37 .", "Body 39 has a flow port 41 extending from its upper end to its lower end for fluid circulation prior to cementing and also for cement 35 flow.", "As shown in FIG. 4 , flow port 41 may be crescent-shaped, and it is offset from the longitudinal axis of body 39 .", "Prior to pumping the cement through displacement sub 29 , flow port 41 is open.", "As shown in FIG. 5 , after pumping cement 35 , the cement will cure within and block flow port 41 .", "Referring to FIG. 3 , a firing head assembly 43 is secured by threads into the upper end of body 39 .", "Firing head assembly 43 is also of drillable materials and is offset from the axis of body 39 .", "Firing head assembly 43 has a housing 45 made up of a number of tubular sections secured and sealed together as shown in FIG. 3 .", "A bore 47 is located within an upper portion of firing head housing 45 .", "Firing head housing 45 has a cap 49 that encloses the upper end of bore 47 .", "A piston 51 is carried within bore 47 for movement from the initial position shown in FIG. 3 to a lower position (not shown).", "Piston 51 is initially spaced with its upper end below cap 49 .", "A chamber 53 at atmospheric pressure is located between the upper end of piston 51 and cap 49 .", "Piston 51 sealingly engages bore 47 and is held in the initial position by shear pins 55 .", "Piston 51 has a downward extending rod with a sharp firing pin 57 fixed to its lower end.", "A percussive detonator 59 is located within firing head housing 45 a short distance below firing pin 57 .", "Detonator 59 is connected to detonating cord 61 , which leads to one or more shaped or perforating charges 63 (only one shown in FIGS. 2 and 3 ).", "Detonator 59 , detonating cord 61 and shaped charges 63 are conventional components used in perforating operations.", "The number of shaped charges 63 can vary.", "Referring to FIG. 2 , an optional dye pack housing 65 is secured by threads to the lower end of body 39 .", "Dye pack housing 65 is also of drillable material and has a sealed chamber that contains a dye.", "When exposed to well bore fluid, the dye will discolor the fluid circulating back to the surface to indicate that displacement sub 29 has been drilled through.", "Referring to FIG. 6 , after cement 35 is cured and the operator has removed setting tool 17 ( FIG. 1 ), the operator runs back into the well with a drill bit 67 on the lower end of drill pipe 15 .", "Drill bit 67 will drill the cement plug (not shown) in collar 27 , and then began drilling components of displacement sub 29 .", "During drilling, the operator pumps drilling fluid through drill pipe 15 , which discharges from drill bit 67 and flows back up the annulus between drill pipe 15 and liner 25 .", "Once drill bit 67 drills through cap 49 ( FIG. 3 ), the pressure of the drilling fluid will be applied to chamber 53 , which was previously at atmospheric pressure.", "The drilling fluid pressure causes shear pins 55 to shear, pushing piston 51 and firing pin 57 downward.", "Firing pin 57 strikes and ignites detonator 59 , which in turn ignites detonating cord 61 and shaped charges 63 .", "The explosion creates perforations 69 through cement 35 and into the earth formation as illustrated in FIGS. 7 and 8 .", "After firing, the operator continues drilling firing head assembly 43 ( FIG. 3 ) and body 39 ( FIG. 2 ).", "When drill bit 67 reaches dye pack assembly 65 , the dye is released.", "The fluid being pumped down drill string 15 causes dye 66 to color the drilling fluid returning to the surface, indicating to the operator that he has now drilled through displacement sub 29 .", "Tile operator stops drilling substantially at this point, leaving cement 35 within extension member 31 and cement shoe 33 .", "The operator then retrieves drill pipe 15 and drill bit 67 ( FIG. 6 ).", "Referring to FIG. 9 , the operator may now perform wireline services in the well, using a wireline tool 73 .", "Wireline tool 73 may be any type of conventional wireline service equipment, such as a gamma ray wireline tool, a cement bond wireline tool, perforating equipment or a plug or packer setting tool.", "Wireline tool 73 may be attached to a pump-down head 71 to facilitate pumping down liner 25 .", "Pump-down head 71 is piston-like member that fits closely within tile inner diameter of liner 25 .", "Because of their large diameter, some wireline tools 73 , such as a bridge plug, may not need an additional pump down head 71 .", "Pump down head 71 is located at the lower end of wireline tool 73 , which is connected to an electrical cable 77 that leads to the surface.", "At the surface, a blowout preventer 79 will close the well in the event of an emergency.", "Blowout preventer 79 may include wireline rams that close around electrical cable 77 as well as shear rams that will cut it.", "A manifold 81 is secured to blowout preventer 79 for pumping fluid, typically water, into casing 11 and liner 25 to force pump-down head 71 downward.", "A lubricator 83 seals around electrical cable 77 as it moves.", "Electrical cable 77 is dispensed by a winch 85 at the surface.", "A logging unit 87 supplies electrical power to electrical cable 77 and receives signals indicating parameters of the earth formations and cement 35 .", "As illustrated in FIG. 9 , fluid 89 is located below pump-down head 71 .", "As pump-down head 71 moves downward, it displaces some of the fluid 89 , which flows into displacement perforations 69 .", "The exterior of pump-down head 71 does not form a tight seal with the inner diameter of liner 25 ;", "rather a small clearance will exist for some of the fluid 89 to flow around pump-down head 71 as it moves downward.", "However, without displacement perforations 69 , it would not be feasible to pump wireline tool 73 to the lower end of liner 25 .", "Preferably, the operator continues pumping down pump-down head 71 until it reaches the lower end of displacement sub 29 .", "Subsequently, the operator will retrieve pump-down head 71 and tool 73 by winding electrical cable 77 back onto winch 85 .", "The operator may perform the log while retrieving tool 73 , or while pumping tool 73 down, or both.", "The operator then may complete the well by running production tubing and perforating in a variety of conventional manners.", "Referring to FIG. 10 , in one completion method, the operator perforates to form production perforations 93 above displacement perforations 69 .", "The production perforations 93 could be made in several ways, one of which could be pumping down through liner 25 a pump-down perforating gun on wireline, with displaced fluid flowing out displacement perforations 69 .", "A bridge plug 91 could then be set above the displacement perforations 69 to isolate them from production perforations.", "The operator may then run a string of production tubing 95 and set a packer 97 in liner 25 above production perforations 93 .", "Tubing 95 is suspended conventionally from a wellhead assembly 99 for conveying well fluid to the surface.", "Alternately, the operator could first set bridge plug 91 , then run tubing 95 , then pump down a perforating gun through tubing 95 with displaced fluid flowing back up the tubing annulus within liner 25 before setting packer 97 .", "The operator could also make the production perforations with a tubing conveyed perforating gun.", "The invention has significant advantages.", "By forming a displacement perforation into the formation, the operator can use a pump-down logging tool, with displacement fluid flowing into the formation.", "Forming the displacement perforation while drilling out the cement avoids an additional trip just to make the displacement perforation.", "This method avoids the need for a tractor, thus saving time and expense.", "While the invention has been shown in only one of its forms, it should be apparent to those skilled in the art that it is not so limited but is susceptible to various changes without departing from the scope of the invention." ]
CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation of U.S. application Ser. No. 10/360,417, filed Feb. 7, 2003, now U.S. Pat. No. 7,077,849, which is a continuation of U.S. application Ser. No. 09/756,093, filed Jan. 8, 2001, and issued as U.S. Pat. No. 6,527,781, which is a continuation of U.S. patent application Ser. No. 09/296,327, filed Apr. 22,1999, and issued as U.S. Patent No. 6,224,612, which claims priority to provisional U.S. Patent Application No. 60/082,810, filed Apr. 23, 1998, and provisional U.S. Patent Application No. 60/1 05,448, filed Oct. 23, 1998. The complete disclosures of all of these patent applications are incorporated by reference herein. TECHNICAL FIELD The invention relates generally to medical devices for retrieving material from within a body. More particularly, the invention relates to medical retrieval baskets that have atraumatic distal ends that are contoured or tipless both to minimize the chances of damage to tissue during use and to enhance the ability of the basket to capture material (e.g., stones) disposed or lodged in “pockets” or other areas that are difficult to access in the body. BACKGROUND INFORMATION Known stone retrieval devices typically have baskets that are constructed by joining multiple legs together at a base of the basket and at a distal end or tip of the basket such that a “cage” is formed. At the distal tip, the individual legs are joined by soldering, adhesives, etc. such that a protruding tip results. This protrusion or outward projection at the distal end of the basket can poke tissue and cause tissue trauma. In general, the tips or ends of known baskets protrude outward and thus can cause damage by poking or piercing tissue. Also, the protruding tips of known baskets generally do not permit access to or intimate contact with certain areas within the body such as “pockets,” and thus stones residing in such areas are difficult or impossible to retrieve with known baskets. SUMMARY OF THE INVENTION It is an object of the invention to provide a medical retrieval basket that does not have a substantially protruding distal basket end or basket tip. That is, a basket according to the invention is atraumatic and does not have any significant distal protrusion or outward projection that can poke tissue, pierce tissue, or otherwise cause trauma to tissue. It is another object of the invention to provide a medical retrieval basket that permits access to and/or intimate contact with certain areas within the body such as “pockets” where material to be retrieved (e.g., stones) might reside or be lodged, impacted, or embedded. A tipless or contoured tip basket arrangement can access these areas and retrieve material from those areas whereas a conventional basket with a traumatic tip would not be able to do so because of the traumatic protruding tip that prevents intimate contact between the distal end of the basket and body tissue. It is yet another object of the invention to provide a method of using such baskets to retrieve material from within a body. The material can be biological or foreign matter. The material can be, for example, urological stones or any of a variety of other types of material found in the body. A basket according to one aspect of the invention is tipless and thus lacks a protruding end or tip. At least a distal end portion of the basket can be formed from a single piece of material to achieve the desired tipless feature. The one-piece construction of at least the distal end portion of the tipless basket can be achieved by removing the desired profile from a flat sheet of construction material or by using an injection mold process. With this type of single unit, one-piece construction, the basket legs require joining only at the base of the basket where the basket is attached to a cable, coil, wire, etc., that connects the basket to a proximal handle mechanism. This single unit feature of baskets according to the invention can be achieved in a variety of ways including stamping, photoetching, laser cutting, and injection molding. Also, various materials can be used to form the tipless one-piece unit or the entire basket such as metal, polymers, ceramics, powdered metals, thermal plastic composites, etc. Combinations of these or other materials also may be used to manufacture a basket according to the invention. The invention generally relates to a medical retrieval device that comprises a sheath, a handle, and an atraumatic basket. The sheath has a proximal end and a distal end. The handle is located at the proximal end of the sheath. The basket can remove material from a body, and it has a collapsed position where the basket is enclosed within the sheath and an expanded position where the basket extends from the distal end of the sheath. The basket can have three or more legs (e.g., four, five, or six legs). At least a distal end portion of the basket is substantially tipless and defined by a shape or profile which comprises a single continuous unit. In another embodiment of the invention, the atraumatic basket is formed by a plurality of wires, each wire forming a loop with a small protrusion at the very distal end of the basket. In accordance with one aspect of the invention, the atraumatic basket has a distal end portion defined by a single continuous, one-piece unit. The atraumatic basket can include the following features. The distal end portion of the atraumatic basket can be non-perforated or perforated to, for example, allow a guidewire or lithotripsy device (laser) to extend through the sheath and through the end of the basket. The shape of the distal end portion of the atraumatic basket can be formed from, for example, metal, metal alloys, a ceramic material, a powdered metal, or a polymer. The basket legs, each of which has an inner surface and an outer surface, can have at least a portion of their inner surfaces coated with an anti-slip material, textured, or roughened in some manner to enhance the ability of the basket to grip and hold material. The atraumatic basket can be made by one-piece construction forming, as a single continuous one-piece unit, a shape having three or more legs, for example, a y-shape, x-shape, t-shape or star-shape, and then bending the legs of the shape to form at least a distal portion of a three-dimensional basket structure that is useful for retrieving objects. Other shapes such as a double loop may be used to form the distal portion of the basket. Shapes other than the ones described here also may be used to form the distal portion of the basket. The shape can be stamped, etched, and/or cut from a continuous sheet of material. Alternatively, the shape could be achieved by injection molding. In another embodiment of an atraumatic wire basket, the distal ends of the basket wires insert into an inverted cap at the distal basket tip. Another aspect of the invention relates to a method for manufacturing a basket for a medical retrieval device comprising the steps of forming, as a single continuous unit, a shape having three or more legs and bending the legs of the shape to form at least a portion of a three-dimensional basket structure for retrieving objects. The shape can be stamped, etched or cut from a continuous sheet of material. The shape can also be injection molded. Yet another aspect of the invention features a method for retrieving material from a body including the steps of inserting an extractor into a body, the extractor including a basket having three or more legs and wherein at least a distal end portion of the basket is defined by a shape which comprises a single continuous unit, capturing the material within the basket and withdrawing the extractor from the body to remove the material from the body. The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. FIG. 1A illustrates a top view of an X-profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention. FIG. 1B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the legs of the X-profile illustrated in FIG. 1A . FIG. 1C illustrates a side view of an embodiment according to the invention of the X-profile illustrated in FIG. 1A . FIG. 1D illustrates an embodiment according to the invention of an end view of the X-profile illustrated in FIG. 1A . FIG. 1E illustrates one embodiment of a medical retrieval device with an atraumatic basket according to the invention with the basket in an expanded position. FIG. 1F illustrates one embodiment of a medical retrieval device with an atraumatic basket according to the invention with the basket in a collapsed position. FIG. 1G illustrates a side view of one embodiment of the invention of a distal end portion of a basket formed by bending and shaping the legs of the X-profile illustrated in FIG. 1A . FIG. 1H illustrates an embodiment of the medical retrieval device according to the invention with a lithotriptic device extending into the basket lumen; FIG. 2A illustrates a top view of one embodiment of an X-profile, one-piece construction of a distal end portion of the basket of the invention. FIG. 2B illustrates details of the center of the X-profile illustrated in FIG. 2A . FIG. 2C illustrates details of the end of one leg of the X-profile illustrated in FIG. 2A . FIG. 2D illustrates embodiments of a cross-section of one of the legs illustrated in FIG. 2A . FIG. 2E illustrates another embodiment of a cross-section of one of the legs illustrated in FIG. 2A . FIG. 2F illustrates one embodiment of a modification of the end of a basket leg; FIG. 3A illustrates a top view of a parachute-shaped profile embodiment of a one-piece construction of a medical retrieval basket removed from a single piece of substantially flat material according to the invention. FIG. 3B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the profile of the parachute shape illustrated in FIG. 3A . FIG. 3C illustrates the basket of FIG. 3B enclosed within a sheath. FIG. 3D illustrates the basket of FIG. 3B extended from the distal end of the sheath. FIG. 4A illustrates a top view of a web-shaped profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention. FIG. 4B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic basket formed by bending and shaping the profile of the web-shaped profile illustrated in FIG. 4A . FIG. 5A illustrates a top view of a double loop-shaped profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention. FIG. 5B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the profile of the double-loop shaped profile illustrated in FIG. 5A . FIG. 6A is a top view of a stamped profile that can be formed into a basket or a portion of a basket by bending the legs of the shape, in accordance with the invention. FIG. 6B is an embodiment according to the invention of a three-dimensional tipless basket with a distal end portion constructed from the profile illustrated in FIG. 6A . FIG. 7A is an embodiment according to the invention of a three-dimensional tipless basket structure formed from a single continuous piece of material, for example, the stamped shape illustrated in FIG. 6A . FIG. 7B is the distal end profile illustrated in FIG. 6A including a textured inner surface of one leg. FIG. 8 is a top view of an embodiment according to the invention of another stamped shape that can be formed into a basket or a portion of a basket by bending the legs of the shape, according to the invention. FIG. 9 illustrates an embodiment according to the invention of a basket with an atraumatic spot-welded tip. FIG. 10 illustrates an embodiment according to the invention of a basket with an atraumatic looped tip. FIG. 11A illustrates a loop of a basket according to the invention. FIG. 11B illustrates an embodiment of a three-dimensional basket according to the invention formed from a plurality of basket loops illustrated in FIG. 11A FIG. 11C illustrates a loop of a basket according to the invention having an atraumatic protrusion with a radius at the distal end. FIG. 11D illustrates an embodiment of a three-dimensional basket according to the invention formed from a plurality of basket loops illustrated in FIG. 11C . FIG. 12A illustrates another embodiment of the basket loop having multiple shoulders illustrated in FIG. 11C . FIG. 12B illustrates yet another embodiment of the basket loop illustrated in FIG. 12A . FIG. 12C illustrates an embodiment of a three-dimensional basket formed from basket loops having multiple shoulders illustrated in 12 A. FIG. 12D illustrates an embodiment of a three-dimensional basket formed from basket loops illustrated in FIG. 12B . FIG. 13A illustrates an inverted cap embodiment of a tipless basket. FIG. 13B illustrates the distal end portion of the inverted cap, tipless basket illustrated in FIG. 13A before the ends of the basket legs are affixed together at the proximal end of the basket. FIG. 13C illustrates the details of the inverted cap illustrated in FIGS. 13A and 13B . FIG. 14 illustrates a metal ring inserted into a polyimide sheath before the metal ring is ground flush with the end of the polyimide sheath. DESCRIPTION All of the following embodiments of the invention generally have at least one thing in common, a basket of a medical retrieval device having a substantially atraumatic tip according to the invention. The basket 10 , shown by way of example in FIG. 1F , is the type that can be collapsed within a sheath 12 for entry into the body. A medical device or extractor that includes the basket 10 of the invention also includes the sheath 12 and a proximal handle 8 . The handle 8 , sheath 12 , and basket 10 illustrated in FIGS. 1E and 1 F are not shown in their correct size or proportion to each other. The size of the entire sheath is dimensioned to fit the requirements of its application in the body. For example, for urological applications, the size of the device is typically 1.7-8.0 Fr. The sheath 12 has at least one lumen 14 therein, may be made from a single material, and extends from the handle 8 to a distal sheath end 16 . An elongated member such as a cable, coil, shaft, guidewire or mandril wire 18 extends within the lumen 14 from an actuating mechanism 4 at the device handle 8 to the base 20 of the basket 10 , where the cable 18 is attached to the basket base 20 . Operation of the actuating mechanism 4 by an operator causes the basket 10 to move in and out of the sheath 12 between a collapsed position within the sheath 12 as illustrated in FIG. 1F to an extended position outside of the sheath 12 where the basket 10 is open/expanded and extending beyond the distal end of the sheath 16 as shown in FIG. 1E . Alternatively, the mechanism 4 can cause movement of the sheath 12 to advance the sheath 12 over the stationary basket 10 and cable 18 combination, to thereby collapse the basket 10 within the sheath 12 , and the mechanism 4 can slide the moveable sheath 12 back to expose the stationary basket 10 and allow it to open/expand. In general, both types of basket/sheath movement configurations and related handle mechanisms are known, and can be seen in existing product designs available from, for example, Boston Scientific Corporation (Natick, Mass.). With the basket collapsed within the sheath 12 as shown in FIG. 1F , the sheath 12 can be inserted into the body by an operator to a site in the body where the material to be retrieved is located (e.g., a stone in the ureter). By putting the basket 10 into its open/expanded position, as illustrated in FIG. 1E , the basket 10 dilates the body tract in which it has been placed and can be manipulated by the operator to entrap or capture material within the basket 10 . The basket 10 and/or the sheath 12 can then be moved to cause the legs 11 a , 11 b , 11 c , 11 d of the basket 10 to close around the material and capture it. The captured material is then withdrawn from the body along with the sheath and the basket that is holding the material. In one aspect, according to the invention, a basket 10 of a device for retrieving biological or foreign material from a body has a plurality of legs, for example, as shown in FIG. 1B , four legs 11 a , 11 b , 11 c , 11 d . An end-on view of the basket 10 in FIG. 1D illustrates a substantially tipless or atraumatic distal end 100 . A small, insubstantial protrusion or depression may remain at the distal tip as a result of the manufacturing process. Such features on the basket tip do not poke, tear, pierce, perforate, bruise or otherwise inflict injury or cause trauma to the tissue and may enhance basket performance. In one embodiment, for example, the legs 11 a , 11 b , 11 c , 11 d and the atraumatic basket 10 can be cut, etched, stamped or otherwise removed as a single shape or profile from a substantially flat piece of material 101 as illustrated in FIG. 1A . In another embodiment, referring to FIGS. 1E , 1 G and 6 B, just the distal end portion 5 of the basket 10 is removed as a single shape or profile from a single piece of substantially flat material. Alternatively, the basket 10 or distal end portion 5 can be injection molded into the desired shape by, for example, plastic injection molding, metal-injection-molding (MIM) or by compression of metal powders. As illustrated in FIG. 1A and FIG. 1C , the starting profile for the basket 10 or the basket end portion 5 can be an X-profile or X-shape. After removal of the X-profile from the flat material, the three-dimensional basket 10 or distal end portion 5 of the basket 10 can be formed by bending and shaping the legs of an X-profile. The starting profile may be asymmetrical. For example, in other embodiments, the starting profile of the basket 10 or the distal end portion 5 can be y-shaped, t-shaped or star-shaped. With continued reference to FIGS. 1B and 1D , the distal end 100 of the basket 10 is uniform, contoured, and substantially without any protruding surface features. That is, in accordance with the invention, the distal end 100 of the basket 10 is substantially devoid of knobs, protrusions, fasteners, or outward projections. The distal end 100 of the basket 10 may be perforated 20 as illustrated in FIG. 1G to permit a guidewire (not shown) to extend through the sheath 12 and out the end of the basket 10 through the perforation 20 . Referring to FIG. 1H , alternatively, a ram-rod, laser or other lithotriptic device 9 is longitudinally disposed in a channel 200 of sheath 12 . Channel 200 extends through the proximal end 20 of the basket 10 . In operation, a stone 50 is captured in the lumen of the basket 10 . The lithotriptic device is advanced beyond the proximal basket end into the basket until the lithotriptic device approaches the stone 50 . The stone 50 is then fragmented by lithotripsy. The fragmented stones are removed from the body while entrapped within the basket 10 . No adhesive or any other attachment material or device is used at the distal end 100 of the basket 10 to hold the legs together as at least the distal ends of the legs are formed by a profile including distal leg portions extracted from a single piece of sheet-like material as illustrated in FIGS. 1A and 1C to form a tipless atraumatic three-dimensional basket as illustrated in FIG. 1B . The distal end 100 of the basket 10 is substantially atraumatic in that it has no substantial outward projections or protrusions that might cause injury or trauma to tissue and/or that might present an impediment to contacting the distal end 100 of the basket 10 directly and intimately with tissue. In one embodiment, referring to FIGS. 2A-2E , a medical device of the invention includes a plurality of legs forming the basket 10 . The legs can have various cross-sectional shapes, for example, as shown in FIGS. 2D and 2E . Other cross-sectional shapes for the legs of the basket 10 include, but are not limited to, a D-shape, a V-shape, a B-shape, rectangular, and cylindrical (not shown). Typically, the length of the legs 11 a , 11 b , 11 c , 11 d is about 0.5 to 3.5 inches, for example, 1.1 to 1.5 inches, the width of the leg is about 0.005 inches to 0.015 inches and the thickness of the legs is 0.028 inches to 0.045 inches. The ends 1 of the basket legs 11 may be modified by narrowing, enlarging or grooving the end for example, as shown in FIG. 2F , to ease assembly and/or strengthen the basket when the ends of the basket legs are brought together. Referring to FIGS. 2A-2C and 2 E, a typical basket end portion may have the following features. The basket end portion can have four legs, the legs being approximately 90° apart. The leg length d 1 is 1.1 inches to 1.25 inches, leg width d 2 is 0.010 inches to 0.012 inches, leg width d 3 is 0.006 inches to 0.008 inches, and leg thickness d 4 is 0.005±0.0003 to 0.0032±0.003 inches. At the intersection 121 of the four legs, the four corners have a slight radius as shown in FIG. 2B . The ends 1 of the legs as illustrated in FIG. 2C have a full radius. Notches or cut-outs 123 are located 0.100 inches (d 6 ) from the end 1 of the leg and have a radius of 0.003-0.004 inches with a minimum distance (d 5 ) of 0.004 inches between the apex of the notches. The “X” profile illustrated in FIG. 2A may be removed from a flat annealed, superelastic, nickel-titanium sheet having a pickled surface and active A f of 15±5° C. The basket 10 or distal end 100 of the basket 10 can be formed from various materials such as stainless steel, metal alloys, superelastic materials, shape memory materials, powdered metals, ceramics, thermal plastic composites, ceramic composites, polymers, etc. Also, combinations of these and other materials can be used. The atraumatic basket 10 can assume shapes more complex than one with three or more legs running parallel and longitudinally from the distal end of the basket to the basket base. For example, referring to FIG. 3A , a single-unit hourglass profile 22 can be removed from a single piece of sheet-like material 101 by stamping, etching, or cutting, for example, according to the invention. A three-dimensional basket 10 can be created by folding the single-unit hourglass profile, as illustrated by the arrows in FIG. 3A , into a substantially parachute-shaped configuration as shown in FIG. 3B . Heat treatment, cold-forming, or other shaping processes using a ball-shaped die is then performed on the parachute-shaped configuration to shape the profile into a three-dimensional basket 10 . The distal end 100 of this basket 10 is tipless and atraumatic. The proximal end 24 of basket 10 can be joined to a cable 18 within a sheath 12 as illustrated in FIG. 3C . The basket 10 is moveable relative to the sheath 12 from a collapsed basket position, shown in FIG. 3C to an open basket position shown in FIG. 3D . In another embodiment, the basket can be made by extracting a single unit web-shaped profile 26 , as illustrated in FIG. 4A , from a single piece of sheet-like material. The web-profile is removed from a single piece of sheet-like material by stamping, etching or cutting, for example. The web-profile is subsequently shaped and molded around a ball shape by heat treatment, cold-forming, or other shaping processes to achieve a basket 10 as illustrated in FIG. 4B . The distal end 100 of this basket 10 is atraumatic and substantially tipless. The proximal end 24 of basket 10 can be joined to a cable (not shown) and the basket can be moved within the lumen of a sheath relative to the sheath in a manner similar to the basket illustrated in FIGS. 3C and 3D . Referring to FIG. 5 , another embodiment of the basket can be made by extracting a single unit double-loop profile 28 from a single piece of material by stamping, etching, or cutting, for example. The double-loop profile 28 is shaped and molded around a ball shape by heat treatment, cold-formed, or by other shaping processes, to form the basket 10 illustrated in FIG. 5B . The distal end 100 of the basket 10 is substantially tipless and atraumatic. The proximal end 24 of the basket can be joined to a cable (not shown) and the basket can be moved within the lumen of a sheath, relative to the sheath in a manner similar to the basket illustrated in FIGS. 3C and 3D . To manufacture a basket according to the invention, a single piece of flat material, such as a sheet of metal, or a single piece of material contoured to conform to the basket radius is used to form the distal basket tip. When starting with a single piece of flat material, at least the distal basket tip is defined by a shape or profile that is removed from the single piece of construction material. The profile can be removed from the material by a variety of methods including, for example, stamping, etching, photoetching, or laser cutting as illustrated in FIG. 1A or 3 A. The profile removed from the single piece of material is then shaped by heat treatment, cold-forming process or by other processes known in the art to form at least a distal end portion 5 as illustrated, for example, in FIGS. 1G and 6B having an atraumatic distal tip, or a three-dimensional basket structure, for example, as illustrated in FIGS. 1B , 3 B, 4 B and 5 B having an atraumatic distal tip. Alternatively, the basket legs may be rotated or twisted slightly around their longitudinal axis to achieve a helical basket, for example, as shown in FIG. 1D . A basket according to the invention also can be formed by injection molding the distal basket portion or desired basket profile. Alternatively, with a metal or plastic injection molding process, the three-dimensional distal basket portion or basket design can be injected into a three-dimensional mold thereby obviating the step of shaping the distal basket portion or basket structure following removal of the profile from a single piece of construction material by molding into a final shape. The basket 10 and basket designs described below are joined at the basket proximal end to the distal end of the elongated member 18 to form a subassembly. The basket/elongated member subassembly is inserted into the sheath 12 and joined to the handle 8 to form the medical retrieval device according to the invention. The “X” profile that is shown in FIG. 6A , for example, can be replaced by any other shape that lends itself to clinical efficiency and manufacturability and that results in a substantially tipless atraumatic basket. The “X” or other profiles can have a small, atraumatic protrusion or depression at the distal basket tip. Also, the “X” profile or other profile, can be shaped to make a distal end portion 5 of the basket 10 , and leg extensions 3 a , 3 b , 3 c , 3 d can be added to end-sections 1 a , 1 b , 1 c , 1 d of legs 11 a , 11 b , 11 c , 11 d to form all of or a portion of the basket legs 11 a , 11 b , 11 c , 11 d as shown in FIG. 6B . Alternatively, the end-sections 1 a , 1 b , 1 c , 1 d of the basket legs 11 a , 11 b , 11 c , 11 d of the “X” profile or any other profile can be secured together at the base 20 of the basket 10 illustrated in FIG. 7A . All or a portion of the inner surface (side toward basket center) of one or more of the basket legs can be treated to enhance the ability of the basket to grasp and hold material to be retrieved. For example, an anti-slip coating, such as a rubberized or plastic coating can be applied to at least a portion of the inner surface of at least one of the basket legs as illustrated on the inner surface 15 of leg 11 b in FIG. 7A . The coating can be applied directly to the single piece of sheet-like material from which the basket profile is extracted before basket formation or to the inner surface of the basket legs after basket formation. An enhanced grasping and/or fragmentation capability also can be achieved by adding texture to at least the inner surface of at least one of the basket legs by, for example, creating serrations, teeth, or points on the inner surface(s). This can be achieved by, for example, etching, pitting, bending, stamping or machining the texture/roughness into the inner surface(s) by application of these methods directly to the single piece of sheet-like material from which the basket or basket distal end shape is extracted before basket formation, or directly to the inner surface of the basket legs after basket formation. Referring to FIGS. 6A , 7 B, and 8 , according to one embodiment of the invention, a profile stamped from a single piece of sheet-like material has end-sections 1 that are brought together at a basket base 20 to form a three-dimensional basket 10 . Alternatively, as illustrated in FIGS. 6A and 6B , just the distal end portion 5 of the basket can be formed from the single piece of construction material with the legs of the basket extending from the end-sections 1 a , 1 b , 1 c , 1 d of the profile and then drawing the end-sections 1 a , 1 b , 1 c , 1 d down and bringing the end-sections together at the basket base 20 to form the basket 10 . As shown in FIG. 8 , it is possible to have more than three or four basket legs by forming the basket distal end from, for example, an eight-leg 11 a , 11 b , 11 c , 11 d , 11 e , 11 f , 11 g , 11 h star-shape profile 28 extracted as a single unit from a single piece of sheet-like material. The shape forming the distal end portion of the basket may be asymmetrical. Baskets that are atraumatic and tipless may also have each leg 11 a , 11 b , 11 c , 11 d joined at the distal end 100 of the basket in a variety of ways such as by spot welding the legs at the distal end 100 as illustrated in FIG. 9 or by looping two or more wires 17 a , 17 b together at the distal end 100 as illustrated in FIG. 10 . The wires are looped together by forming a loop in a mid-portion of the first wire 17 a . Second wire 17 b is passed through the loop of the first wire 17 a . The second wire 17 b is looped within and is held by the loop of the first wire 17 a. Referring to FIGS. 11A and 11B , in another embodiment of the invention, a tipless end 130 of the atraumatic basket 10 is constructed by using single wires to form loops 120 a , 120 b having legs 11 a , 11 b , 11 c , 11 d extending from the apex 130 a , 130 b of the loops 120 a and 120 b , respectively, the apex 130 a , 130 b positioned at the basket distal end 100 . A plurality of pre-formed wire loops is included in a three-dimensional, atraumatic basket Wire loops may be formed from plastics, superelastic materials, stainless steel, shape memory metals, ceramic composites, other composites, or other materials and may have any of a variety of cross sectional shapes such as D-shape, B-shape, U-shape, round, half-round, oval, rectangular or ribbon-like. In this embodiment of an atraumatic wire basket, two wire loops 120 a , 120 b , for example, may be used to form a basket with four legs 11 a , 11 b , 11 c , 11 d as shown in FIG. 11A , and three wire loops 120 a , 120 b , 120 c may be used to form a basket with six legs 11 a , 11 b , 11 c , 11 d , 11 e , 11 f as shown in FIG. 11B . Additional wire loops may be used to form a basket with more than the four or six legs shown. The apex 130 of each wire loop 120 intersects the apex 130 of the other wire loops 120 of the basket 1 O at the basket distal end 100 . The wire loops 120 at the basket distal end 100 are free to slide by one another, i.e., they are not affixed, fused, soldered, welded, glued, joined, secured or attached to one another. The advantages of this configuration of the basket is that the basket end 100 is atraumatic and provides flexibility thereby enhancing the ease by which stones are captured. The two end-sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding, soldering, ligating, gluing, crimping or any other means known in the art. In one embodiment, the end-sections 1 , 1 ′ of the wire loops are affixed (not shown) to a cable, coil, shaft, mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in FIG. 1E and FIG. 1F . Referring to FIGS. 11C and 11D , the tipless end 100 of the atraumatic basket can also be constructed by using single pre-formed wires to form modified loops 120 , each modified loop having a pair of legs 11 a , 11 b extending from the apex 130 of the loop 120 , the apex 130 positioned at the basket distal end 100 . The apex 130 of a pre-formed wire loop 120 forming pairs of basket legs is modified to stabilize the basket tip. For example, as illustrated in FIG. 11C , the apex 130 of a wire loop 120 is modified by a protrusion 140 with a radius, such as a semi-circular protrusion. A basket may be formed by a plurality of wire loops 120 a , 120 b , each wire loop having a small protrusion 140 a , 140 b with a radius, as illustrated in FIG. 11D . Each semi-circular protrusion on the basket wire has a convex surface 142 and a concave surface 144 as illustrated in FIG. 11C . In this embodiment, the convex surface 142 of the semi-circular protrusion 140 of wire loop 120 a meets the concave surface 144 of the semi-circular protrusion 140 of the outer wire loop 120 b where the wires of the basket cross one another at the basket distal tip 100 as illustrated in FIG. 11D . At the apex 130 where the loops cross one another at the distal end of the basket, the wires forming the loops are not adhered, affixed, fused, soldered, welded, glued or joined to one another. Typically, two or more wires (i.e., loops), each with a semi-circular protrusion, are used to form an atraumatic wire basket. Wire loops 120 may be formed from superelastic materials, stainless steel, shape memory metals, ceramic composites, other composites, or other materials and may have any of a variety of cross sectional shapes such as D-shape, B-shape, U-shape, round, half-round, oval, rectangular, or ribbon-like. In this embodiment of an atraumatic wire basket, for example, two wire loops 120 a , 120 b may be used to form a basket with four legs as shown in FIG. 11C , or three wire loops may be used to form a basket with six legs (not shown), and so on. Additional wire loops may be used to form a basket with more than the four or six legs shown. Referring to FIG. 11C , the two end-sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding, soldering, ligating, gluing, crimping or any other means known in the art. The end-sections 1 , 1 ′ of the wire loops can be affixed as shown in FIG. 11D to a cable, coil, shaft, mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in FIG. 1E and FIG. 1F . A channel 200 may run through the sheath 12 and the proximal end 20 of the basket 10 to accommodate a ram-rod, laser or other lithotriptic device 9 as shown in FIG. 1H and described earlier. A basket of the invention having two or more wire loops 120 a , 120 b each with semi-circular protrusions 140 at the apex 130 of the loops 120 a , 120 b , has enhanced basket stability and dilatative strength without substantially compromising basket flexibility. In this embodiment of the invention ( FIGS. 11C and 11D ), the wires are unlikely to slide by one another at the distal tip. The semi-circular protrusions also help to reduce the stress on the basket legs while closing the basket. The legs of an atraumatic wire basket 10 illustrated in FIGS. 11A-11D and FIGS. 12A-12D may be gently curved or may have a plurality of angular bends. In one embodiment, illustrated in FIG. 12A , each of the legs 11 a , 11 b of a loop 120 a have five angular bends, 17 a , 17 a′ , 17 a″ , 17 a′″ , 17 a″″ forming at least two shoulders 15 ′ and 15 ″ on each leg 11 a , 11 b of the wire loop 120 . A three-dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in FIG. 12A is shown in FIG. 12B . FIG. 12A illustrates a wire loop 120 configuration where all of the angles 17 of the loop are obtuse. A three-dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in FIG. 12A is shown in FIG. 12C . An infinite number of obtuse angles in both legs of the wire loop results in a smoothly curved loop as illustrated in FIG. 12B . A largely oval or round, atraumatic three-dimensional basket shape 10 formed by two basket loops 120 a , 120 b of the type illustrated in FIG. 12B is shown in FIG. 12D . The legs 11 a , 11 b , 11 c , 11 d of the baskets illustrated in FIGS. 11B , 11 D, 12 C and 12 D may be pre-formed, and their cross-section may be B-shaped, D-shaped, U-shaped, round, half-round, oval, rectangular, ribbon-like, or a variety of other cross-sectional shapes such as those shown in FIGS. 2D and 2E . In yet another embodiment of an atraumatic wire basket illustrated in FIG. 13A , the distal ends 3 a , 3 b , 3 c , 3 d of the basket wires 3 insert into a cap 160 with a core 170 at the basket tip 100 as shown in FIG. 13C . The distal ends 3 a , 3 b , 3 c , 3 d of the wires are affixed to the cap 160 by soldering, gluing or any means known in the art. The wires emerging from the cap are bent and then drawn down proximally as indicated by the arrows in FIG. 13B to form basket legs 11 a , 11 b , 11 c , 11 d . The end-sections of the legs 1 a , 1 b , 1 c , 1 d are gathered together at the basket base 20 to form an atraumatic wire basket 10 as shown in FIG. 13A . The end-sections 1 a , 1 b , 1 c , 1 d can be joined to a cable, shaft or coil (not shown). In some embodiments of the invention, the sheath 12 of the medical retrieval device is manufactured from polyimide, PTFE, composites or similar materials. In order to prevent the distal end 16 of a polyimide sheath 12 from splitting, a metal ring 180 , as illustrated in FIG. 14 , is inserted into the lumen 14 of the distal end 16 of a polyimide sheath 12 . The metal ring 180 is flush with the end 16 of the polyimide sheath or may protrude slightly beyond the end of the sheath as illustrated in FIG. 14 . In yet another aspect, the invention relates to a method for retrieving material from a body such as a body tract or body canal. Material (e.g., biological or foreign) can be retrieved from a body by using a tipless basket where at least a distal portion of the basket is defined by a shape which comprises a single unit or by using an atraumatic wire loop basket, each basket wire forming a loop with a distal atraumatic protrusion. The basket of the retrieval device has a tipless or an atraumatic distal end and thus allows the capture of material that is located in pockets or other difficult-to-access areas within the body. Because the distal basket end is atraumatic, it can make intimate contact with the surface of tissue, even the walls or lining of a pocket-type area, and allows the retrieval of stones or other materials that are unrecoverable with conventional tipped baskets that can cause tissue trauma and are limited, by the existence of the protruding tip, in how close the basket can approach the tissue. A method for retrieving material from a body includes inserting a retrieval device with an atraumatic basket into the body, moving the tipless basket into the extended position, maneuvering the basket via one or more actuators on the proximal handle (which is located outside of the body) of the retrieval device until the material (e.g., stone) is entrapped within the three-dimensional basket structure, and capturing the material within the basket by moving the basket relative to the sheath to close the basket legs around the material. With the material so gripped or held by the basket, the basket can be withdrawn from the body to remove the material from the body. Before the basket is withdrawn from the body with the captured material, the material can be broken apart by, for example, laser energy or lithotripsy. Mechanisms for breaking up the material before its removal from the body can be part of the retrieval device or can be separate tools/devices that are also inserted into the body and utilized at the appropriate time in the stone removal procedure. The material that can be captured with tipless baskets according to the invention includes a thrombus, embolus, foreign body, calculus, or a stone, such as a kidney stone, a ureteral stone, a urinary bladder stone, a gall bladder stone, a stone within the biliary tree, tumor, polyp or foreign body. Variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the invention is to be defined not by the preceding illustrative description but instead by the spirit and scope of the following claims.
Baskets with atraumatic distal tips allow the capture of material from difficult-to-reach areas of the body, while reducing the risk of tissue damage.
Provide a concise summary of the essential information conveyed in the context.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS This is a continuation of U.S. application Ser.", "No. 10/360,417, filed Feb. 7, 2003, now U.S. Pat. No. 7,077,849, which is a continuation of U.S. application Ser.", "No. 09/756,093, filed Jan. 8, 2001, and issued as U.S. Pat. No. 6,527,781, which is a continuation of U.S. patent application Ser.", "No. 09/296,327, filed Apr. 22,1999, and issued as U.S. Patent No. 6,224,612, which claims priority to provisional U.S. Patent Application No. 60/082,810, filed Apr. 23, 1998, and provisional U.S. Patent Application No. 60/1 05,448, filed Oct. 23, 1998.", "The complete disclosures of all of these patent applications are incorporated by reference herein.", "TECHNICAL FIELD The invention relates generally to medical devices for retrieving material from within a body.", "More particularly, the invention relates to medical retrieval baskets that have atraumatic distal ends that are contoured or tipless both to minimize the chances of damage to tissue during use and to enhance the ability of the basket to capture material (e.g., stones) disposed or lodged in “pockets”", "or other areas that are difficult to access in the body.", "BACKGROUND INFORMATION Known stone retrieval devices typically have baskets that are constructed by joining multiple legs together at a base of the basket and at a distal end or tip of the basket such that a “cage”", "is formed.", "At the distal tip, the individual legs are joined by soldering, adhesives, etc.", "such that a protruding tip results.", "This protrusion or outward projection at the distal end of the basket can poke tissue and cause tissue trauma.", "In general, the tips or ends of known baskets protrude outward and thus can cause damage by poking or piercing tissue.", "Also, the protruding tips of known baskets generally do not permit access to or intimate contact with certain areas within the body such as “pockets,” and thus stones residing in such areas are difficult or impossible to retrieve with known baskets.", "SUMMARY OF THE INVENTION It is an object of the invention to provide a medical retrieval basket that does not have a substantially protruding distal basket end or basket tip.", "That is, a basket according to the invention is atraumatic and does not have any significant distal protrusion or outward projection that can poke tissue, pierce tissue, or otherwise cause trauma to tissue.", "It is another object of the invention to provide a medical retrieval basket that permits access to and/or intimate contact with certain areas within the body such as “pockets”", "where material to be retrieved (e.g., stones) might reside or be lodged, impacted, or embedded.", "A tipless or contoured tip basket arrangement can access these areas and retrieve material from those areas whereas a conventional basket with a traumatic tip would not be able to do so because of the traumatic protruding tip that prevents intimate contact between the distal end of the basket and body tissue.", "It is yet another object of the invention to provide a method of using such baskets to retrieve material from within a body.", "The material can be biological or foreign matter.", "The material can be, for example, urological stones or any of a variety of other types of material found in the body.", "A basket according to one aspect of the invention is tipless and thus lacks a protruding end or tip.", "At least a distal end portion of the basket can be formed from a single piece of material to achieve the desired tipless feature.", "The one-piece construction of at least the distal end portion of the tipless basket can be achieved by removing the desired profile from a flat sheet of construction material or by using an injection mold process.", "With this type of single unit, one-piece construction, the basket legs require joining only at the base of the basket where the basket is attached to a cable, coil, wire, etc.", ", that connects the basket to a proximal handle mechanism.", "This single unit feature of baskets according to the invention can be achieved in a variety of ways including stamping, photoetching, laser cutting, and injection molding.", "Also, various materials can be used to form the tipless one-piece unit or the entire basket such as metal, polymers, ceramics, powdered metals, thermal plastic composites, etc.", "Combinations of these or other materials also may be used to manufacture a basket according to the invention.", "The invention generally relates to a medical retrieval device that comprises a sheath, a handle, and an atraumatic basket.", "The sheath has a proximal end and a distal end.", "The handle is located at the proximal end of the sheath.", "The basket can remove material from a body, and it has a collapsed position where the basket is enclosed within the sheath and an expanded position where the basket extends from the distal end of the sheath.", "The basket can have three or more legs (e.g., four, five, or six legs).", "At least a distal end portion of the basket is substantially tipless and defined by a shape or profile which comprises a single continuous unit.", "In another embodiment of the invention, the atraumatic basket is formed by a plurality of wires, each wire forming a loop with a small protrusion at the very distal end of the basket.", "In accordance with one aspect of the invention, the atraumatic basket has a distal end portion defined by a single continuous, one-piece unit.", "The atraumatic basket can include the following features.", "The distal end portion of the atraumatic basket can be non-perforated or perforated to, for example, allow a guidewire or lithotripsy device (laser) to extend through the sheath and through the end of the basket.", "The shape of the distal end portion of the atraumatic basket can be formed from, for example, metal, metal alloys, a ceramic material, a powdered metal, or a polymer.", "The basket legs, each of which has an inner surface and an outer surface, can have at least a portion of their inner surfaces coated with an anti-slip material, textured, or roughened in some manner to enhance the ability of the basket to grip and hold material.", "The atraumatic basket can be made by one-piece construction forming, as a single continuous one-piece unit, a shape having three or more legs, for example, a y-shape, x-shape, t-shape or star-shape, and then bending the legs of the shape to form at least a distal portion of a three-dimensional basket structure that is useful for retrieving objects.", "Other shapes such as a double loop may be used to form the distal portion of the basket.", "Shapes other than the ones described here also may be used to form the distal portion of the basket.", "The shape can be stamped, etched, and/or cut from a continuous sheet of material.", "Alternatively, the shape could be achieved by injection molding.", "In another embodiment of an atraumatic wire basket, the distal ends of the basket wires insert into an inverted cap at the distal basket tip.", "Another aspect of the invention relates to a method for manufacturing a basket for a medical retrieval device comprising the steps of forming, as a single continuous unit, a shape having three or more legs and bending the legs of the shape to form at least a portion of a three-dimensional basket structure for retrieving objects.", "The shape can be stamped, etched or cut from a continuous sheet of material.", "The shape can also be injection molded.", "Yet another aspect of the invention features a method for retrieving material from a body including the steps of inserting an extractor into a body, the extractor including a basket having three or more legs and wherein at least a distal end portion of the basket is defined by a shape which comprises a single continuous unit, capturing the material within the basket and withdrawing the extractor from the body to remove the material from the body.", "The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.", "BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, like reference characters generally refer to the same parts throughout the different views.", "Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.", "FIG. 1A illustrates a top view of an X-profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention.", "FIG. 1B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the legs of the X-profile illustrated in FIG. 1A .", "FIG. 1C illustrates a side view of an embodiment according to the invention of the X-profile illustrated in FIG. 1A .", "FIG. 1D illustrates an embodiment according to the invention of an end view of the X-profile illustrated in FIG. 1A .", "FIG. 1E illustrates one embodiment of a medical retrieval device with an atraumatic basket according to the invention with the basket in an expanded position.", "FIG. 1F illustrates one embodiment of a medical retrieval device with an atraumatic basket according to the invention with the basket in a collapsed position.", "FIG. 1G illustrates a side view of one embodiment of the invention of a distal end portion of a basket formed by bending and shaping the legs of the X-profile illustrated in FIG. 1A .", "FIG. 1H illustrates an embodiment of the medical retrieval device according to the invention with a lithotriptic device extending into the basket lumen;", "FIG. 2A illustrates a top view of one embodiment of an X-profile, one-piece construction of a distal end portion of the basket of the invention.", "FIG. 2B illustrates details of the center of the X-profile illustrated in FIG. 2A .", "FIG. 2C illustrates details of the end of one leg of the X-profile illustrated in FIG. 2A .", "FIG. 2D illustrates embodiments of a cross-section of one of the legs illustrated in FIG. 2A .", "FIG. 2E illustrates another embodiment of a cross-section of one of the legs illustrated in FIG. 2A .", "FIG. 2F illustrates one embodiment of a modification of the end of a basket leg;", "FIG. 3A illustrates a top view of a parachute-shaped profile embodiment of a one-piece construction of a medical retrieval basket removed from a single piece of substantially flat material according to the invention.", "FIG. 3B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the profile of the parachute shape illustrated in FIG. 3A .", "FIG. 3C illustrates the basket of FIG. 3B enclosed within a sheath.", "FIG. 3D illustrates the basket of FIG. 3B extended from the distal end of the sheath.", "FIG. 4A illustrates a top view of a web-shaped profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention.", "FIG. 4B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic basket formed by bending and shaping the profile of the web-shaped profile illustrated in FIG. 4A .", "FIG. 5A illustrates a top view of a double loop-shaped profile embodiment of a one-piece construction of at least a distal end portion of a medical retrieval basket removed from a single piece of substantially flat material according to the invention.", "FIG. 5B illustrates a side view of an embodiment according to the invention of a three-dimensional atraumatic tipless basket formed by bending and shaping the profile of the double-loop shaped profile illustrated in FIG. 5A .", "FIG. 6A is a top view of a stamped profile that can be formed into a basket or a portion of a basket by bending the legs of the shape, in accordance with the invention.", "FIG. 6B is an embodiment according to the invention of a three-dimensional tipless basket with a distal end portion constructed from the profile illustrated in FIG. 6A .", "FIG. 7A is an embodiment according to the invention of a three-dimensional tipless basket structure formed from a single continuous piece of material, for example, the stamped shape illustrated in FIG. 6A .", "FIG. 7B is the distal end profile illustrated in FIG. 6A including a textured inner surface of one leg.", "FIG. 8 is a top view of an embodiment according to the invention of another stamped shape that can be formed into a basket or a portion of a basket by bending the legs of the shape, according to the invention.", "FIG. 9 illustrates an embodiment according to the invention of a basket with an atraumatic spot-welded tip.", "FIG. 10 illustrates an embodiment according to the invention of a basket with an atraumatic looped tip.", "FIG. 11A illustrates a loop of a basket according to the invention.", "FIG. 11B illustrates an embodiment of a three-dimensional basket according to the invention formed from a plurality of basket loops illustrated in FIG. 11A FIG. 11C illustrates a loop of a basket according to the invention having an atraumatic protrusion with a radius at the distal end.", "FIG. 11D illustrates an embodiment of a three-dimensional basket according to the invention formed from a plurality of basket loops illustrated in FIG. 11C .", "FIG. 12A illustrates another embodiment of the basket loop having multiple shoulders illustrated in FIG. 11C .", "FIG. 12B illustrates yet another embodiment of the basket loop illustrated in FIG. 12A .", "FIG. 12C illustrates an embodiment of a three-dimensional basket formed from basket loops having multiple shoulders illustrated in 12 A. FIG. 12D illustrates an embodiment of a three-dimensional basket formed from basket loops illustrated in FIG. 12B .", "FIG. 13A illustrates an inverted cap embodiment of a tipless basket.", "FIG. 13B illustrates the distal end portion of the inverted cap, tipless basket illustrated in FIG. 13A before the ends of the basket legs are affixed together at the proximal end of the basket.", "FIG. 13C illustrates the details of the inverted cap illustrated in FIGS. 13A and 13B .", "FIG. 14 illustrates a metal ring inserted into a polyimide sheath before the metal ring is ground flush with the end of the polyimide sheath.", "DESCRIPTION All of the following embodiments of the invention generally have at least one thing in common, a basket of a medical retrieval device having a substantially atraumatic tip according to the invention.", "The basket 10 , shown by way of example in FIG. 1F , is the type that can be collapsed within a sheath 12 for entry into the body.", "A medical device or extractor that includes the basket 10 of the invention also includes the sheath 12 and a proximal handle 8 .", "The handle 8 , sheath 12 , and basket 10 illustrated in FIGS. 1E and 1 F are not shown in their correct size or proportion to each other.", "The size of the entire sheath is dimensioned to fit the requirements of its application in the body.", "For example, for urological applications, the size of the device is typically 1.7-8.0 Fr.", "The sheath 12 has at least one lumen 14 therein, may be made from a single material, and extends from the handle 8 to a distal sheath end 16 .", "An elongated member such as a cable, coil, shaft, guidewire or mandril wire 18 extends within the lumen 14 from an actuating mechanism 4 at the device handle 8 to the base 20 of the basket 10 , where the cable 18 is attached to the basket base 20 .", "Operation of the actuating mechanism 4 by an operator causes the basket 10 to move in and out of the sheath 12 between a collapsed position within the sheath 12 as illustrated in FIG. 1F to an extended position outside of the sheath 12 where the basket 10 is open/expanded and extending beyond the distal end of the sheath 16 as shown in FIG. 1E .", "Alternatively, the mechanism 4 can cause movement of the sheath 12 to advance the sheath 12 over the stationary basket 10 and cable 18 combination, to thereby collapse the basket 10 within the sheath 12 , and the mechanism 4 can slide the moveable sheath 12 back to expose the stationary basket 10 and allow it to open/expand.", "In general, both types of basket/sheath movement configurations and related handle mechanisms are known, and can be seen in existing product designs available from, for example, Boston Scientific Corporation (Natick, Mass.).", "With the basket collapsed within the sheath 12 as shown in FIG. 1F , the sheath 12 can be inserted into the body by an operator to a site in the body where the material to be retrieved is located (e.g., a stone in the ureter).", "By putting the basket 10 into its open/expanded position, as illustrated in FIG. 1E , the basket 10 dilates the body tract in which it has been placed and can be manipulated by the operator to entrap or capture material within the basket 10 .", "The basket 10 and/or the sheath 12 can then be moved to cause the legs 11 a , 11 b , 11 c , 11 d of the basket 10 to close around the material and capture it.", "The captured material is then withdrawn from the body along with the sheath and the basket that is holding the material.", "In one aspect, according to the invention, a basket 10 of a device for retrieving biological or foreign material from a body has a plurality of legs, for example, as shown in FIG. 1B , four legs 11 a , 11 b , 11 c , 11 d .", "An end-on view of the basket 10 in FIG. 1D illustrates a substantially tipless or atraumatic distal end 100 .", "A small, insubstantial protrusion or depression may remain at the distal tip as a result of the manufacturing process.", "Such features on the basket tip do not poke, tear, pierce, perforate, bruise or otherwise inflict injury or cause trauma to the tissue and may enhance basket performance.", "In one embodiment, for example, the legs 11 a , 11 b , 11 c , 11 d and the atraumatic basket 10 can be cut, etched, stamped or otherwise removed as a single shape or profile from a substantially flat piece of material 101 as illustrated in FIG. 1A .", "In another embodiment, referring to FIGS. 1E , 1 G and 6 B, just the distal end portion 5 of the basket 10 is removed as a single shape or profile from a single piece of substantially flat material.", "Alternatively, the basket 10 or distal end portion 5 can be injection molded into the desired shape by, for example, plastic injection molding, metal-injection-molding (MIM) or by compression of metal powders.", "As illustrated in FIG. 1A and FIG. 1C , the starting profile for the basket 10 or the basket end portion 5 can be an X-profile or X-shape.", "After removal of the X-profile from the flat material, the three-dimensional basket 10 or distal end portion 5 of the basket 10 can be formed by bending and shaping the legs of an X-profile.", "The starting profile may be asymmetrical.", "For example, in other embodiments, the starting profile of the basket 10 or the distal end portion 5 can be y-shaped, t-shaped or star-shaped.", "With continued reference to FIGS. 1B and 1D , the distal end 100 of the basket 10 is uniform, contoured, and substantially without any protruding surface features.", "That is, in accordance with the invention, the distal end 100 of the basket 10 is substantially devoid of knobs, protrusions, fasteners, or outward projections.", "The distal end 100 of the basket 10 may be perforated 20 as illustrated in FIG. 1G to permit a guidewire (not shown) to extend through the sheath 12 and out the end of the basket 10 through the perforation 20 .", "Referring to FIG. 1H , alternatively, a ram-rod, laser or other lithotriptic device 9 is longitudinally disposed in a channel 200 of sheath 12 .", "Channel 200 extends through the proximal end 20 of the basket 10 .", "In operation, a stone 50 is captured in the lumen of the basket 10 .", "The lithotriptic device is advanced beyond the proximal basket end into the basket until the lithotriptic device approaches the stone 50 .", "The stone 50 is then fragmented by lithotripsy.", "The fragmented stones are removed from the body while entrapped within the basket 10 .", "No adhesive or any other attachment material or device is used at the distal end 100 of the basket 10 to hold the legs together as at least the distal ends of the legs are formed by a profile including distal leg portions extracted from a single piece of sheet-like material as illustrated in FIGS. 1A and 1C to form a tipless atraumatic three-dimensional basket as illustrated in FIG. 1B .", "The distal end 100 of the basket 10 is substantially atraumatic in that it has no substantial outward projections or protrusions that might cause injury or trauma to tissue and/or that might present an impediment to contacting the distal end 100 of the basket 10 directly and intimately with tissue.", "In one embodiment, referring to FIGS. 2A-2E , a medical device of the invention includes a plurality of legs forming the basket 10 .", "The legs can have various cross-sectional shapes, for example, as shown in FIGS. 2D and 2E .", "Other cross-sectional shapes for the legs of the basket 10 include, but are not limited to, a D-shape, a V-shape, a B-shape, rectangular, and cylindrical (not shown).", "Typically, the length of the legs 11 a , 11 b , 11 c , 11 d is about 0.5 to 3.5 inches, for example, 1.1 to 1.5 inches, the width of the leg is about 0.005 inches to 0.015 inches and the thickness of the legs is 0.028 inches to 0.045 inches.", "The ends 1 of the basket legs 11 may be modified by narrowing, enlarging or grooving the end for example, as shown in FIG. 2F , to ease assembly and/or strengthen the basket when the ends of the basket legs are brought together.", "Referring to FIGS. 2A-2C and 2 E, a typical basket end portion may have the following features.", "The basket end portion can have four legs, the legs being approximately 90° apart.", "The leg length d 1 is 1.1 inches to 1.25 inches, leg width d 2 is 0.010 inches to 0.012 inches, leg width d 3 is 0.006 inches to 0.008 inches, and leg thickness d 4 is 0.005±0.0003 to 0.0032±0.003 inches.", "At the intersection 121 of the four legs, the four corners have a slight radius as shown in FIG. 2B .", "The ends 1 of the legs as illustrated in FIG. 2C have a full radius.", "Notches or cut-outs 123 are located 0.100 inches (d 6 ) from the end 1 of the leg and have a radius of 0.003-0.004 inches with a minimum distance (d 5 ) of 0.004 inches between the apex of the notches.", "The “X”", "profile illustrated in FIG. 2A may be removed from a flat annealed, superelastic, nickel-titanium sheet having a pickled surface and active A f of 15±5° C. The basket 10 or distal end 100 of the basket 10 can be formed from various materials such as stainless steel, metal alloys, superelastic materials, shape memory materials, powdered metals, ceramics, thermal plastic composites, ceramic composites, polymers, etc.", "Also, combinations of these and other materials can be used.", "The atraumatic basket 10 can assume shapes more complex than one with three or more legs running parallel and longitudinally from the distal end of the basket to the basket base.", "For example, referring to FIG. 3A , a single-unit hourglass profile 22 can be removed from a single piece of sheet-like material 101 by stamping, etching, or cutting, for example, according to the invention.", "A three-dimensional basket 10 can be created by folding the single-unit hourglass profile, as illustrated by the arrows in FIG. 3A , into a substantially parachute-shaped configuration as shown in FIG. 3B .", "Heat treatment, cold-forming, or other shaping processes using a ball-shaped die is then performed on the parachute-shaped configuration to shape the profile into a three-dimensional basket 10 .", "The distal end 100 of this basket 10 is tipless and atraumatic.", "The proximal end 24 of basket 10 can be joined to a cable 18 within a sheath 12 as illustrated in FIG. 3C .", "The basket 10 is moveable relative to the sheath 12 from a collapsed basket position, shown in FIG. 3C to an open basket position shown in FIG. 3D .", "In another embodiment, the basket can be made by extracting a single unit web-shaped profile 26 , as illustrated in FIG. 4A , from a single piece of sheet-like material.", "The web-profile is removed from a single piece of sheet-like material by stamping, etching or cutting, for example.", "The web-profile is subsequently shaped and molded around a ball shape by heat treatment, cold-forming, or other shaping processes to achieve a basket 10 as illustrated in FIG. 4B .", "The distal end 100 of this basket 10 is atraumatic and substantially tipless.", "The proximal end 24 of basket 10 can be joined to a cable (not shown) and the basket can be moved within the lumen of a sheath relative to the sheath in a manner similar to the basket illustrated in FIGS. 3C and 3D .", "Referring to FIG. 5 , another embodiment of the basket can be made by extracting a single unit double-loop profile 28 from a single piece of material by stamping, etching, or cutting, for example.", "The double-loop profile 28 is shaped and molded around a ball shape by heat treatment, cold-formed, or by other shaping processes, to form the basket 10 illustrated in FIG. 5B .", "The distal end 100 of the basket 10 is substantially tipless and atraumatic.", "The proximal end 24 of the basket can be joined to a cable (not shown) and the basket can be moved within the lumen of a sheath, relative to the sheath in a manner similar to the basket illustrated in FIGS. 3C and 3D .", "To manufacture a basket according to the invention, a single piece of flat material, such as a sheet of metal, or a single piece of material contoured to conform to the basket radius is used to form the distal basket tip.", "When starting with a single piece of flat material, at least the distal basket tip is defined by a shape or profile that is removed from the single piece of construction material.", "The profile can be removed from the material by a variety of methods including, for example, stamping, etching, photoetching, or laser cutting as illustrated in FIG. 1A or 3 A. The profile removed from the single piece of material is then shaped by heat treatment, cold-forming process or by other processes known in the art to form at least a distal end portion 5 as illustrated, for example, in FIGS. 1G and 6B having an atraumatic distal tip, or a three-dimensional basket structure, for example, as illustrated in FIGS. 1B , 3 B, 4 B and 5 B having an atraumatic distal tip.", "Alternatively, the basket legs may be rotated or twisted slightly around their longitudinal axis to achieve a helical basket, for example, as shown in FIG. 1D .", "A basket according to the invention also can be formed by injection molding the distal basket portion or desired basket profile.", "Alternatively, with a metal or plastic injection molding process, the three-dimensional distal basket portion or basket design can be injected into a three-dimensional mold thereby obviating the step of shaping the distal basket portion or basket structure following removal of the profile from a single piece of construction material by molding into a final shape.", "The basket 10 and basket designs described below are joined at the basket proximal end to the distal end of the elongated member 18 to form a subassembly.", "The basket/elongated member subassembly is inserted into the sheath 12 and joined to the handle 8 to form the medical retrieval device according to the invention.", "The “X”", "profile that is shown in FIG. 6A , for example, can be replaced by any other shape that lends itself to clinical efficiency and manufacturability and that results in a substantially tipless atraumatic basket.", "The “X”", "or other profiles can have a small, atraumatic protrusion or depression at the distal basket tip.", "Also, the “X”", "profile or other profile, can be shaped to make a distal end portion 5 of the basket 10 , and leg extensions 3 a , 3 b , 3 c , 3 d can be added to end-sections 1 a , 1 b , 1 c , 1 d of legs 11 a , 11 b , 11 c , 11 d to form all of or a portion of the basket legs 11 a , 11 b , 11 c , 11 d as shown in FIG. 6B .", "Alternatively, the end-sections 1 a , 1 b , 1 c , 1 d of the basket legs 11 a , 11 b , 11 c , 11 d of the “X”", "profile or any other profile can be secured together at the base 20 of the basket 10 illustrated in FIG. 7A .", "All or a portion of the inner surface (side toward basket center) of one or more of the basket legs can be treated to enhance the ability of the basket to grasp and hold material to be retrieved.", "For example, an anti-slip coating, such as a rubberized or plastic coating can be applied to at least a portion of the inner surface of at least one of the basket legs as illustrated on the inner surface 15 of leg 11 b in FIG. 7A .", "The coating can be applied directly to the single piece of sheet-like material from which the basket profile is extracted before basket formation or to the inner surface of the basket legs after basket formation.", "An enhanced grasping and/or fragmentation capability also can be achieved by adding texture to at least the inner surface of at least one of the basket legs by, for example, creating serrations, teeth, or points on the inner surface(s).", "This can be achieved by, for example, etching, pitting, bending, stamping or machining the texture/roughness into the inner surface(s) by application of these methods directly to the single piece of sheet-like material from which the basket or basket distal end shape is extracted before basket formation, or directly to the inner surface of the basket legs after basket formation.", "Referring to FIGS. 6A , 7 B, and 8 , according to one embodiment of the invention, a profile stamped from a single piece of sheet-like material has end-sections 1 that are brought together at a basket base 20 to form a three-dimensional basket 10 .", "Alternatively, as illustrated in FIGS. 6A and 6B , just the distal end portion 5 of the basket can be formed from the single piece of construction material with the legs of the basket extending from the end-sections 1 a , 1 b , 1 c , 1 d of the profile and then drawing the end-sections 1 a , 1 b , 1 c , 1 d down and bringing the end-sections together at the basket base 20 to form the basket 10 .", "As shown in FIG. 8 , it is possible to have more than three or four basket legs by forming the basket distal end from, for example, an eight-leg 11 a , 11 b , 11 c , 11 d , 11 e , 11 f , 11 g , 11 h star-shape profile 28 extracted as a single unit from a single piece of sheet-like material.", "The shape forming the distal end portion of the basket may be asymmetrical.", "Baskets that are atraumatic and tipless may also have each leg 11 a , 11 b , 11 c , 11 d joined at the distal end 100 of the basket in a variety of ways such as by spot welding the legs at the distal end 100 as illustrated in FIG. 9 or by looping two or more wires 17 a , 17 b together at the distal end 100 as illustrated in FIG. 10 .", "The wires are looped together by forming a loop in a mid-portion of the first wire 17 a .", "Second wire 17 b is passed through the loop of the first wire 17 a .", "The second wire 17 b is looped within and is held by the loop of the first wire 17 a. Referring to FIGS. 11A and 11B , in another embodiment of the invention, a tipless end 130 of the atraumatic basket 10 is constructed by using single wires to form loops 120 a , 120 b having legs 11 a , 11 b , 11 c , 11 d extending from the apex 130 a , 130 b of the loops 120 a and 120 b , respectively, the apex 130 a , 130 b positioned at the basket distal end 100 .", "A plurality of pre-formed wire loops is included in a three-dimensional, atraumatic basket Wire loops may be formed from plastics, superelastic materials, stainless steel, shape memory metals, ceramic composites, other composites, or other materials and may have any of a variety of cross sectional shapes such as D-shape, B-shape, U-shape, round, half-round, oval, rectangular or ribbon-like.", "In this embodiment of an atraumatic wire basket, two wire loops 120 a , 120 b , for example, may be used to form a basket with four legs 11 a , 11 b , 11 c , 11 d as shown in FIG. 11A , and three wire loops 120 a , 120 b , 120 c may be used to form a basket with six legs 11 a , 11 b , 11 c , 11 d , 11 e , 11 f as shown in FIG. 11B .", "Additional wire loops may be used to form a basket with more than the four or six legs shown.", "The apex 130 of each wire loop 120 intersects the apex 130 of the other wire loops 120 of the basket 1 O at the basket distal end 100 .", "The wire loops 120 at the basket distal end 100 are free to slide by one another, i.e., they are not affixed, fused, soldered, welded, glued, joined, secured or attached to one another.", "The advantages of this configuration of the basket is that the basket end 100 is atraumatic and provides flexibility thereby enhancing the ease by which stones are captured.", "The two end-sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding, soldering, ligating, gluing, crimping or any other means known in the art.", "In one embodiment, the end-sections 1 , 1 ′ of the wire loops are affixed (not shown) to a cable, coil, shaft, mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in FIG. 1E and FIG. 1F .", "Referring to FIGS. 11C and 11D , the tipless end 100 of the atraumatic basket can also be constructed by using single pre-formed wires to form modified loops 120 , each modified loop having a pair of legs 11 a , 11 b extending from the apex 130 of the loop 120 , the apex 130 positioned at the basket distal end 100 .", "The apex 130 of a pre-formed wire loop 120 forming pairs of basket legs is modified to stabilize the basket tip.", "For example, as illustrated in FIG. 11C , the apex 130 of a wire loop 120 is modified by a protrusion 140 with a radius, such as a semi-circular protrusion.", "A basket may be formed by a plurality of wire loops 120 a , 120 b , each wire loop having a small protrusion 140 a , 140 b with a radius, as illustrated in FIG. 11D .", "Each semi-circular protrusion on the basket wire has a convex surface 142 and a concave surface 144 as illustrated in FIG. 11C .", "In this embodiment, the convex surface 142 of the semi-circular protrusion 140 of wire loop 120 a meets the concave surface 144 of the semi-circular protrusion 140 of the outer wire loop 120 b where the wires of the basket cross one another at the basket distal tip 100 as illustrated in FIG. 11D .", "At the apex 130 where the loops cross one another at the distal end of the basket, the wires forming the loops are not adhered, affixed, fused, soldered, welded, glued or joined to one another.", "Typically, two or more wires (i.e., loops), each with a semi-circular protrusion, are used to form an atraumatic wire basket.", "Wire loops 120 may be formed from superelastic materials, stainless steel, shape memory metals, ceramic composites, other composites, or other materials and may have any of a variety of cross sectional shapes such as D-shape, B-shape, U-shape, round, half-round, oval, rectangular, or ribbon-like.", "In this embodiment of an atraumatic wire basket, for example, two wire loops 120 a , 120 b may be used to form a basket with four legs as shown in FIG. 11C , or three wire loops may be used to form a basket with six legs (not shown), and so on.", "Additional wire loops may be used to form a basket with more than the four or six legs shown.", "Referring to FIG. 11C , the two end-sections 1 , 1 ′ of each wire loop are brought together at the basket base 20 and held in place by welding, soldering, ligating, gluing, crimping or any other means known in the art.", "The end-sections 1 , 1 ′ of the wire loops can be affixed as shown in FIG. 11D to a cable, coil, shaft, mandril wire or guidewire 18 that runs longitudinally in a sheath 12 as shown in FIG. 1E and FIG. 1F .", "A channel 200 may run through the sheath 12 and the proximal end 20 of the basket 10 to accommodate a ram-rod, laser or other lithotriptic device 9 as shown in FIG. 1H and described earlier.", "A basket of the invention having two or more wire loops 120 a , 120 b each with semi-circular protrusions 140 at the apex 130 of the loops 120 a , 120 b , has enhanced basket stability and dilatative strength without substantially compromising basket flexibility.", "In this embodiment of the invention ( FIGS. 11C and 11D ), the wires are unlikely to slide by one another at the distal tip.", "The semi-circular protrusions also help to reduce the stress on the basket legs while closing the basket.", "The legs of an atraumatic wire basket 10 illustrated in FIGS. 11A-11D and FIGS. 12A-12D may be gently curved or may have a plurality of angular bends.", "In one embodiment, illustrated in FIG. 12A , each of the legs 11 a , 11 b of a loop 120 a have five angular bends, 17 a , 17 a′ , 17 a″ , 17 a′″ , 17 a″″ forming at least two shoulders 15 ′ and 15 ″ on each leg 11 a , 11 b of the wire loop 120 .", "A three-dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in FIG. 12A is shown in FIG. 12B .", "FIG. 12A illustrates a wire loop 120 configuration where all of the angles 17 of the loop are obtuse.", "A three-dimensional basket shape formed by two loops 120 a , 120 b of the type illustrated in FIG. 12A is shown in FIG. 12C .", "An infinite number of obtuse angles in both legs of the wire loop results in a smoothly curved loop as illustrated in FIG. 12B .", "A largely oval or round, atraumatic three-dimensional basket shape 10 formed by two basket loops 120 a , 120 b of the type illustrated in FIG. 12B is shown in FIG. 12D .", "The legs 11 a , 11 b , 11 c , 11 d of the baskets illustrated in FIGS. 11B , 11 D, 12 C and 12 D may be pre-formed, and their cross-section may be B-shaped, D-shaped, U-shaped, round, half-round, oval, rectangular, ribbon-like, or a variety of other cross-sectional shapes such as those shown in FIGS. 2D and 2E .", "In yet another embodiment of an atraumatic wire basket illustrated in FIG. 13A , the distal ends 3 a , 3 b , 3 c , 3 d of the basket wires 3 insert into a cap 160 with a core 170 at the basket tip 100 as shown in FIG. 13C .", "The distal ends 3 a , 3 b , 3 c , 3 d of the wires are affixed to the cap 160 by soldering, gluing or any means known in the art.", "The wires emerging from the cap are bent and then drawn down proximally as indicated by the arrows in FIG. 13B to form basket legs 11 a , 11 b , 11 c , 11 d .", "The end-sections of the legs 1 a , 1 b , 1 c , 1 d are gathered together at the basket base 20 to form an atraumatic wire basket 10 as shown in FIG. 13A .", "The end-sections 1 a , 1 b , 1 c , 1 d can be joined to a cable, shaft or coil (not shown).", "In some embodiments of the invention, the sheath 12 of the medical retrieval device is manufactured from polyimide, PTFE, composites or similar materials.", "In order to prevent the distal end 16 of a polyimide sheath 12 from splitting, a metal ring 180 , as illustrated in FIG. 14 , is inserted into the lumen 14 of the distal end 16 of a polyimide sheath 12 .", "The metal ring 180 is flush with the end 16 of the polyimide sheath or may protrude slightly beyond the end of the sheath as illustrated in FIG. 14 .", "In yet another aspect, the invention relates to a method for retrieving material from a body such as a body tract or body canal.", "Material (e.g., biological or foreign) can be retrieved from a body by using a tipless basket where at least a distal portion of the basket is defined by a shape which comprises a single unit or by using an atraumatic wire loop basket, each basket wire forming a loop with a distal atraumatic protrusion.", "The basket of the retrieval device has a tipless or an atraumatic distal end and thus allows the capture of material that is located in pockets or other difficult-to-access areas within the body.", "Because the distal basket end is atraumatic, it can make intimate contact with the surface of tissue, even the walls or lining of a pocket-type area, and allows the retrieval of stones or other materials that are unrecoverable with conventional tipped baskets that can cause tissue trauma and are limited, by the existence of the protruding tip, in how close the basket can approach the tissue.", "A method for retrieving material from a body includes inserting a retrieval device with an atraumatic basket into the body, moving the tipless basket into the extended position, maneuvering the basket via one or more actuators on the proximal handle (which is located outside of the body) of the retrieval device until the material (e.g., stone) is entrapped within the three-dimensional basket structure, and capturing the material within the basket by moving the basket relative to the sheath to close the basket legs around the material.", "With the material so gripped or held by the basket, the basket can be withdrawn from the body to remove the material from the body.", "Before the basket is withdrawn from the body with the captured material, the material can be broken apart by, for example, laser energy or lithotripsy.", "Mechanisms for breaking up the material before its removal from the body can be part of the retrieval device or can be separate tools/devices that are also inserted into the body and utilized at the appropriate time in the stone removal procedure.", "The material that can be captured with tipless baskets according to the invention includes a thrombus, embolus, foreign body, calculus, or a stone, such as a kidney stone, a ureteral stone, a urinary bladder stone, a gall bladder stone, a stone within the biliary tree, tumor, polyp or foreign body.", "Variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention as claimed.", "Accordingly, the invention is to be defined not by the preceding illustrative description but instead by the spirit and scope of the following claims." ]
This is a Continuation-in-Part application of application Ser. No. 08/191,578 filed Feb. 2, 1994 and issued as U.S. Pat. No. 5,507,115. FIELD OF THE INVENTION This invention relates means for applying herbicides to control of weeds. More specifically, it relates to an apparatus for selectively directing weed-killing chemicals to weeds under open-field conditions. BACKGROUND TO THE INVENTION Environmental and economic concerns are forcing agricultural producers to modify traditional practices to remain viable. Soil conservation, moisture conservation, and herbicide costs are the primary concerns facing the North American agricultural producer. In most dry land farming the crops are moisture limited so that a field must be rotated, using a fallow year. The traditional practice in fallow is to use tillage to control the weeds. However in dry land conditions the use of tillage promotes moisture loss and soil erosion. Leaving the field to stubble reduces the moisture loss and soil erosion. The stubble is useful in trapping snow during the winter, reduces the evaporation during the summer, and fixes the soil to reduce erosion. Chemical fallow procedures use herbicides to control the weeds in stubble. Traditionally chemical weed control procedures for land in fallow require the applicator to spray the entire field. Broadcast spraying of herbicide for weed control is more expensive, in the short term, than tillage. Techniques have been developed to detect weeds in fallow or stubble fields so that the weeds can be selectively sprayed without spraying the entire field. Current general usage does not, however, adequately control the release of the herbicide spray. This is particularly true where the spraying boom must be swept in an arc. The present invention allows the applicator to more selectively spray weeds in stubble or fallow, thus reducing the cost of chemically controlled fallow. A prior art selective sprayer product sold under the trademark Detect-Spray by an Australian company is described in U.S. Pat. No. 5,144,767. Two further patents that specifically contemplate synchronizing the release of herbicide with the speed of all the spray nozzles carried by the vehicle boom are U.S. Pat. Nos. 5,222,324 and 5,278,423. The present invention has as its objective the provision of an improved means for directing herbicidal spray at selected weeds and particularly weeds in portions of fallow or stubble fields where the farm implement providing weed-control chemicals must sweep out a radius while the chemicals are being applied to such weeds. The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter. These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation. The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification. SUMMARY OF THE INVENTION The invention in its broadest aspect provides a means by which identified weeds are selectively sprayed with herbicide through use of multiple spray nozzles. The timing of the release of herbicide spray from each individual nozzle is co-ordinated with the speed with which each nozzle is passing over the ground. The individual speed at which each nozzle is passing over the ground is determined by measuring the ground speed at two points from within the structures carrying the nozzles, and extrapolating the ground speed of each nozzle in accordance with its location within the structure. The controller provides a delay means that allows for the passage of time between the identification of a weed by a weed sensor, and the release of herbicidal spray by each individual weed spray nozzle as it passes over the ground, ensuring that herbicide is primarily released in order to arrive at the location where weeds have been detected. The object is to have the field of spray of each nozzle correspond with the probable presence of weeds, irrespective of the ground speed of each nozzle. In a preferred embodiment, Ground Speed sensors are installed at two separated locations along with the booms carrying the spray nozzles, preferably at the boom ends causing them to traverse the field at the most sensitive locations for detecting differences in ground speed. In particular, controlled release is co-ordinated with the ground during the turning of the booms while the farm implement changes its direction of travel in the field. The foregoing summarizes the principal features of the invention and some of its optional aspects. The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow. SUMMARY OF THE FIGURES FIG. 1 is a functional block diagram of the weed detection and spray control functions of the invention; FIG. 2 is a functional block diagram of the weed sensor system; FIG. 3 is a schematic block diagram of the components of a multi-unit spray control system; and FIG. 4 is a plan view of a tractor pulling a boom with spray nozzles, viewing sensors and speed sensors. FIG. 5 is a profile schematic view of a viewing sensor and nozzle on the boom. FIG. 6 is a perspective schematic depiction of the elements of FIG. 6 plus a ground speed sensor mounted on the boom. FIG. 7 is a depiction of the tractor of FIG. 4 as it sweeps its nozzle carrying booms in an arc. DESCRIPTION OF THE PREFERRED EMBODIMENT The invention in respect of the identification of objects will be exemplified by reference to a weed control system. For convenience, the invention and its variants will hereafter be referred to as the Spray Vision System. The described weed detection system is only one example of a weed detection methodology and other means for detecting weeds may be employed. The functional block diagram of the Spray Vision System shown in FIG. 1 provides a Weed Sensor which measures through chromatic filters the reflected chromagraphic light (Reflected Light) and, by comparison with the ambient chromagraphic light (Ambient Light) to produce a reflectance value, provides the Weed Signal. This is done by generating a chromatic vector based on four bands of the electromagnetic spectrum. Although four bands are preferred, at least three may be used. The Ambient Light is the amount of ambient light coming from the sky. The Reflected Light is the light reflected from the target area. The Weed Signal is, in the preferred mode, a four dimensional vector which is used to provide an estimation of the amount of weeds in the field-of-view. The Weed Detector compares the Weed Signal in a colour space transform to the Weed Threshold, with an internally provided comparative standard, and determines if there is a basis to issue the Weed Present signal and effect the automatic spraying of the weeds. The Weed Threshold is an operator-adjustable level. The Weed Present signal is issued if the Weed Signal exceeds the Weed Threshold; otherwise the Weed Present signal is cleared. The Estimate Sensor Speed function in FIG. 1 provides a signal based on the speed of at least two Sensors, or their equivalent, as they travel over the ground. These speed values can be provided from one of three different sources: by operator input, by a speed sensor mounted on the tractor, or by measuring the speed of the boom or nozzle support structure as it passes over the ground. The Operator Input Speed parameter is preferably the default speed that can be entered by the operator from the cab of the tractor. The Tractor Speed parameter is determined by interfacing the System to the speedometer, or a groundspeed sensor, on the tractor. The Boom Speed parameter uses one or more groundspeed sensors located along the boom(s), preferably at or near the tips of the boom. Using this input data and knowing the location of each nozzle along the boom(s) the Spray Vision Controller then calculates the ground speed of each nozzle relative to it's position on the boom and controls release of herbicide. The Speed Mode input is an operator input to allow the operator to select which method of estimating speed to use. The Spray Vision Controller is a microprocessor which uses the various inputs to control the operation of each nozzle solenoid (via SolenoidCntl) that releases chemical herbicide. The Controller also sends status and alarm information to the operator. The Solenoid Control Mode (SolenoidCntlMode) sets the operation of the Spray Vision Controller to one of three modes (OFF, ON, and AUTO). In the OFF mode the Solenoid Control (SolenoidCntl) output is forced to be off. In the ON mode the Solenoid Control is forced on. In the AUTO mode the Solenoid Control is determined by the Weed Present signal and the Sensor Distance (SensorDistance) which is the spacing between the Weed Sensor and the nozzle in the direction of travel. The Sensor Distance, Sensor Speed, and the Solenoid Control turn-on delay inputs are used by the Spray Vision Controller to calculate the delay between when a Weed Present signal is generated or set, and when the Solenoid Control should be set to release herbicide from a nozzle. The objective of this calculation is to release the chemical herbicide from the nozzle at the moment when the nozzle passes over a weed. The delay function, and timing established by the Spray Vision Controller provides the valuable benefit of minimizing the consumption of herbicide by restricting its dispersal to substantially the area where weeds are located. The Status Display (StatusDspl) output in FIG. 1 indicates if the Spray Vision Sensor is spraying or not. The Alarm indicates if the Spray Vision Sensor or system has a problem or fault. The Power Indication (PwrInd) indicates if there is power applied to the system. The Weed Sensor may measure the presence of weeds by the preferred method described in U.S. application Ser. No. 08/191,578, now U.S. Pat. No. 5,507,115, the contents of which are adopted herein by reference. The invention preferably uses distributed microprocessor-based sensors to detect and selectively spray the weeds in a field. The system uses a distributed communications system to allow the individual units to exchange information for added flexibility and reliability. The system is designed in a modular fashion to allow for system flexibility and low cost, mass manufactured units. A simplified physical block diagram of the Spray Vision System is given in FIG. 3. The Spray Vision Network allows the units to communicate with each other, to send operator commands to the Sensor Units, transmit ambient light levels to the sensors, transmit the ground speed, display status and alarms to the Operator Panel, and distribute power to the units. As the Spray Vision System uses a distributed control structure, each Spray Vision Sensor contains a microprocessor that executes the decision algorithm and controls the solenoid locally. All of the relevant information required to execute the decision algorithm is transmitted to the sensor over the distributed communications system. The status and fault conditions of the sensor can be transmitted to other units using the communications satem also. The alternative of a centralized controller, while possible, can reduce the reliability of the system because of the number of electrical connections, and because the centralized controller is typically more complex than the individual distributed controllers. The reliability of a centralized controller is typically lower than the reliability of a distributed control system because if the centralized controller fails then the entire system has failed; however if a distributed controller fails then only a small incremental portion of the system is inoperative and the rest of the system operates normally. The input speed of the unit to be used by each of the micro processors can be optionally entered at the Operation Panel, monitored at the tractor, or measured by the Speed Units located on the booms, the herbicide carrier or on the tractor. Preferably 2 Speed Sensors are utilized, one at either end of the boom, as shown in FIG. 4. The use of two ground speed measurements taken from separated locations within the nozzle support structure allows the Spray Vision Controller to compensate for tractor speed and turns. Use of two boom-mounted Speed Units is optional and the system employing the invention can operate on the basis of two ground speed inputs, one of which may be obtained using the tractor ground speed or an operator input speed which is attributed to a specific portion of the assembly, e.g. the tractor. A variety of known ground speed measuring devices may be employed. These may operate on the basis of sonar, radar, laser light and may include wheel or speedometer-coupled wheel sensors. One sonar based system sold under the trade mark TRAK-STAR is referenced in U.S. Pat. No. 4,728,954. In FIG. 4, a preferred arrangement is depicted in which a tractor 30 pulls a boom 31 carrying nozzles 32 with solenoids 33. Viewing sensors 34 and preferably two speed sensors 35 are located at the outermost ends of the boom 31. A sprayer tank 36 provides herbicide through tubing (not shown) to the nozzles 32. Power for the solenoids 33 originates from the power distribution assembly 37. An ambient light sensor 38 measures ambient light and an operator display 39 provides information to the operator. In FIG. 5, the viewing sensor 34 has a field-of-view 40, and the nozzle 32 has a field-of-spray 41. The micro-processor 45 for activation of the solenoid 33 times the opening of the nozzle 32 to allow for the speed over the ground 42 of the part of the boom 31 carrying each nozzle 32 in the direction of travel 43, as well as for the delay taken by the herbicide to pass from the nozzle 32 to the ground 42. In FIG. 6, a sonar or radar-type speed sensor 35 located along at a boom end views the ground and detects (from the motion of the image or by other means) the speed of the boom end 44 (where the sensor 35 is located) over the ground 42. As shown in FIG. 7, as the tractor wheels through a turn the individual processors/controllers 45 at each nozzle 32 receive the ground speed signal of at least two of the speed sensors 35 via wires 46. Based on their known locations along the boom 31, the individual controllers 45a can interpolate the ground speed for their assigned nozzle 32a. This permits individual adjustment of the timing of the release of herbicide by a nozzle to ensure that the field-of-view 40 and field-of-spray 41 overlap, even when the boom 31 is sweeping-out an arc. Conclusion The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use. These embodiments are only exemplary. The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow. These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described. They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein.
A selective spraying weed control system utilizes weed detectors that identify weeds in a field of view and releases herbicide from individual nozzles. The timing of the release of herbicide from each nozzle is controlled to correspond to the actual ground speed of each nozzle. Such actual ground speed is extrapolated from direct measurements of ground speed taken from two separate locations in the weed spraying apparatus, and from the location of each nozzle within the apparatus.
Concisely explain the essential features and purpose of the invention.
[ "This is a Continuation-in-Part application of application Ser.", "No. 08/191,578 filed Feb. 2, 1994 and issued as U.S. Pat. No. 5,507,115.", "FIELD OF THE INVENTION This invention relates means for applying herbicides to control of weeds.", "More specifically, it relates to an apparatus for selectively directing weed-killing chemicals to weeds under open-field conditions.", "BACKGROUND TO THE INVENTION Environmental and economic concerns are forcing agricultural producers to modify traditional practices to remain viable.", "Soil conservation, moisture conservation, and herbicide costs are the primary concerns facing the North American agricultural producer.", "In most dry land farming the crops are moisture limited so that a field must be rotated, using a fallow year.", "The traditional practice in fallow is to use tillage to control the weeds.", "However in dry land conditions the use of tillage promotes moisture loss and soil erosion.", "Leaving the field to stubble reduces the moisture loss and soil erosion.", "The stubble is useful in trapping snow during the winter, reduces the evaporation during the summer, and fixes the soil to reduce erosion.", "Chemical fallow procedures use herbicides to control the weeds in stubble.", "Traditionally chemical weed control procedures for land in fallow require the applicator to spray the entire field.", "Broadcast spraying of herbicide for weed control is more expensive, in the short term, than tillage.", "Techniques have been developed to detect weeds in fallow or stubble fields so that the weeds can be selectively sprayed without spraying the entire field.", "Current general usage does not, however, adequately control the release of the herbicide spray.", "This is particularly true where the spraying boom must be swept in an arc.", "The present invention allows the applicator to more selectively spray weeds in stubble or fallow, thus reducing the cost of chemically controlled fallow.", "A prior art selective sprayer product sold under the trademark Detect-Spray by an Australian company is described in U.S. Pat. No. 5,144,767.", "Two further patents that specifically contemplate synchronizing the release of herbicide with the speed of all the spray nozzles carried by the vehicle boom are U.S. Pat. Nos. 5,222,324 and 5,278,423.", "The present invention has as its objective the provision of an improved means for directing herbicidal spray at selected weeds and particularly weeds in portions of fallow or stubble fields where the farm implement providing weed-control chemicals must sweep out a radius while the chemicals are being applied to such weeds.", "The invention in its general form will first be described, and then its implementation in terms of specific embodiments will be detailed with reference to the drawings following hereafter.", "These embodiments are intended to demonstrate the principle of the invention, and the manner of its implementation.", "The invention in its broadest and more specific forms will then be further described, and defined, in each of the individual claims which conclude this Specification.", "SUMMARY OF THE INVENTION The invention in its broadest aspect provides a means by which identified weeds are selectively sprayed with herbicide through use of multiple spray nozzles.", "The timing of the release of herbicide spray from each individual nozzle is co-ordinated with the speed with which each nozzle is passing over the ground.", "The individual speed at which each nozzle is passing over the ground is determined by measuring the ground speed at two points from within the structures carrying the nozzles, and extrapolating the ground speed of each nozzle in accordance with its location within the structure.", "The controller provides a delay means that allows for the passage of time between the identification of a weed by a weed sensor, and the release of herbicidal spray by each individual weed spray nozzle as it passes over the ground, ensuring that herbicide is primarily released in order to arrive at the location where weeds have been detected.", "The object is to have the field of spray of each nozzle correspond with the probable presence of weeds, irrespective of the ground speed of each nozzle.", "In a preferred embodiment, Ground Speed sensors are installed at two separated locations along with the booms carrying the spray nozzles, preferably at the boom ends causing them to traverse the field at the most sensitive locations for detecting differences in ground speed.", "In particular, controlled release is co-ordinated with the ground during the turning of the booms while the farm implement changes its direction of travel in the field.", "The foregoing summarizes the principal features of the invention and some of its optional aspects.", "The invention may be further understood by the description of the preferred embodiments, in conjunction with the drawings, which now follow.", "SUMMARY OF THE FIGURES FIG. 1 is a functional block diagram of the weed detection and spray control functions of the invention;", "FIG. 2 is a functional block diagram of the weed sensor system;", "FIG. 3 is a schematic block diagram of the components of a multi-unit spray control system;", "and FIG. 4 is a plan view of a tractor pulling a boom with spray nozzles, viewing sensors and speed sensors.", "FIG. 5 is a profile schematic view of a viewing sensor and nozzle on the boom.", "FIG. 6 is a perspective schematic depiction of the elements of FIG. 6 plus a ground speed sensor mounted on the boom.", "FIG. 7 is a depiction of the tractor of FIG. 4 as it sweeps its nozzle carrying booms in an arc.", "DESCRIPTION OF THE PREFERRED EMBODIMENT The invention in respect of the identification of objects will be exemplified by reference to a weed control system.", "For convenience, the invention and its variants will hereafter be referred to as the Spray Vision System.", "The described weed detection system is only one example of a weed detection methodology and other means for detecting weeds may be employed.", "The functional block diagram of the Spray Vision System shown in FIG. 1 provides a Weed Sensor which measures through chromatic filters the reflected chromagraphic light (Reflected Light) and, by comparison with the ambient chromagraphic light (Ambient Light) to produce a reflectance value, provides the Weed Signal.", "This is done by generating a chromatic vector based on four bands of the electromagnetic spectrum.", "Although four bands are preferred, at least three may be used.", "The Ambient Light is the amount of ambient light coming from the sky.", "The Reflected Light is the light reflected from the target area.", "The Weed Signal is, in the preferred mode, a four dimensional vector which is used to provide an estimation of the amount of weeds in the field-of-view.", "The Weed Detector compares the Weed Signal in a colour space transform to the Weed Threshold, with an internally provided comparative standard, and determines if there is a basis to issue the Weed Present signal and effect the automatic spraying of the weeds.", "The Weed Threshold is an operator-adjustable level.", "The Weed Present signal is issued if the Weed Signal exceeds the Weed Threshold;", "otherwise the Weed Present signal is cleared.", "The Estimate Sensor Speed function in FIG. 1 provides a signal based on the speed of at least two Sensors, or their equivalent, as they travel over the ground.", "These speed values can be provided from one of three different sources: by operator input, by a speed sensor mounted on the tractor, or by measuring the speed of the boom or nozzle support structure as it passes over the ground.", "The Operator Input Speed parameter is preferably the default speed that can be entered by the operator from the cab of the tractor.", "The Tractor Speed parameter is determined by interfacing the System to the speedometer, or a groundspeed sensor, on the tractor.", "The Boom Speed parameter uses one or more groundspeed sensors located along the boom(s), preferably at or near the tips of the boom.", "Using this input data and knowing the location of each nozzle along the boom(s) the Spray Vision Controller then calculates the ground speed of each nozzle relative to it's position on the boom and controls release of herbicide.", "The Speed Mode input is an operator input to allow the operator to select which method of estimating speed to use.", "The Spray Vision Controller is a microprocessor which uses the various inputs to control the operation of each nozzle solenoid (via SolenoidCntl) that releases chemical herbicide.", "The Controller also sends status and alarm information to the operator.", "The Solenoid Control Mode (SolenoidCntlMode) sets the operation of the Spray Vision Controller to one of three modes (OFF, ON, and AUTO).", "In the OFF mode the Solenoid Control (SolenoidCntl) output is forced to be off.", "In the ON mode the Solenoid Control is forced on.", "In the AUTO mode the Solenoid Control is determined by the Weed Present signal and the Sensor Distance (SensorDistance) which is the spacing between the Weed Sensor and the nozzle in the direction of travel.", "The Sensor Distance, Sensor Speed, and the Solenoid Control turn-on delay inputs are used by the Spray Vision Controller to calculate the delay between when a Weed Present signal is generated or set, and when the Solenoid Control should be set to release herbicide from a nozzle.", "The objective of this calculation is to release the chemical herbicide from the nozzle at the moment when the nozzle passes over a weed.", "The delay function, and timing established by the Spray Vision Controller provides the valuable benefit of minimizing the consumption of herbicide by restricting its dispersal to substantially the area where weeds are located.", "The Status Display (StatusDspl) output in FIG. 1 indicates if the Spray Vision Sensor is spraying or not.", "The Alarm indicates if the Spray Vision Sensor or system has a problem or fault.", "The Power Indication (PwrInd) indicates if there is power applied to the system.", "The Weed Sensor may measure the presence of weeds by the preferred method described in U.S. application Ser.", "No. 08/191,578, now U.S. Pat. No. 5,507,115, the contents of which are adopted herein by reference.", "The invention preferably uses distributed microprocessor-based sensors to detect and selectively spray the weeds in a field.", "The system uses a distributed communications system to allow the individual units to exchange information for added flexibility and reliability.", "The system is designed in a modular fashion to allow for system flexibility and low cost, mass manufactured units.", "A simplified physical block diagram of the Spray Vision System is given in FIG. 3. The Spray Vision Network allows the units to communicate with each other, to send operator commands to the Sensor Units, transmit ambient light levels to the sensors, transmit the ground speed, display status and alarms to the Operator Panel, and distribute power to the units.", "As the Spray Vision System uses a distributed control structure, each Spray Vision Sensor contains a microprocessor that executes the decision algorithm and controls the solenoid locally.", "All of the relevant information required to execute the decision algorithm is transmitted to the sensor over the distributed communications system.", "The status and fault conditions of the sensor can be transmitted to other units using the communications satem also.", "The alternative of a centralized controller, while possible, can reduce the reliability of the system because of the number of electrical connections, and because the centralized controller is typically more complex than the individual distributed controllers.", "The reliability of a centralized controller is typically lower than the reliability of a distributed control system because if the centralized controller fails then the entire system has failed;", "however if a distributed controller fails then only a small incremental portion of the system is inoperative and the rest of the system operates normally.", "The input speed of the unit to be used by each of the micro processors can be optionally entered at the Operation Panel, monitored at the tractor, or measured by the Speed Units located on the booms, the herbicide carrier or on the tractor.", "Preferably 2 Speed Sensors are utilized, one at either end of the boom, as shown in FIG. 4. The use of two ground speed measurements taken from separated locations within the nozzle support structure allows the Spray Vision Controller to compensate for tractor speed and turns.", "Use of two boom-mounted Speed Units is optional and the system employing the invention can operate on the basis of two ground speed inputs, one of which may be obtained using the tractor ground speed or an operator input speed which is attributed to a specific portion of the assembly, e.g. the tractor.", "A variety of known ground speed measuring devices may be employed.", "These may operate on the basis of sonar, radar, laser light and may include wheel or speedometer-coupled wheel sensors.", "One sonar based system sold under the trade mark TRAK-STAR is referenced in U.S. Pat. No. 4,728,954.", "In FIG. 4, a preferred arrangement is depicted in which a tractor 30 pulls a boom 31 carrying nozzles 32 with solenoids 33.", "Viewing sensors 34 and preferably two speed sensors 35 are located at the outermost ends of the boom 31.", "A sprayer tank 36 provides herbicide through tubing (not shown) to the nozzles 32.", "Power for the solenoids 33 originates from the power distribution assembly 37.", "An ambient light sensor 38 measures ambient light and an operator display 39 provides information to the operator.", "In FIG. 5, the viewing sensor 34 has a field-of-view 40, and the nozzle 32 has a field-of-spray 41.", "The micro-processor 45 for activation of the solenoid 33 times the opening of the nozzle 32 to allow for the speed over the ground 42 of the part of the boom 31 carrying each nozzle 32 in the direction of travel 43, as well as for the delay taken by the herbicide to pass from the nozzle 32 to the ground 42.", "In FIG. 6, a sonar or radar-type speed sensor 35 located along at a boom end views the ground and detects (from the motion of the image or by other means) the speed of the boom end 44 (where the sensor 35 is located) over the ground 42.", "As shown in FIG. 7, as the tractor wheels through a turn the individual processors/controllers 45 at each nozzle 32 receive the ground speed signal of at least two of the speed sensors 35 via wires 46.", "Based on their known locations along the boom 31, the individual controllers 45a can interpolate the ground speed for their assigned nozzle 32a.", "This permits individual adjustment of the timing of the release of herbicide by a nozzle to ensure that the field-of-view 40 and field-of-spray 41 overlap, even when the boom 31 is sweeping-out an arc.", "Conclusion The foregoing has constituted a description of specific embodiments showing how the invention may be applied and put into use.", "These embodiments are only exemplary.", "The invention in its broadest, and more specific aspects, is further described and defined in the claims which now follow.", "These claims, and the language used therein, are to be understood in terms of the variants of the invention which have been described.", "They are not to be restricted to such variants, but are to be read as covering the full scope of the invention as is implicit within the invention and the disclosure that has been provided herein." ]
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to, and is a National Phase of, International Application No. PCT/EP2012/068873, filed on Sep. 25, 2012, which in turn claims priority to European Patent Application No. 11183508.8, filed on Sep. 30, 2011, which applications are hereby incorporated by reference in their entirety. BACKGROUND A clutch assembly of a motor vehicle transmits drive power to a wheel of an axle, and may include a clutch-controlled equalisation unit, having a clutch device. The equalization unit can be engaged and disengaged and can transmit drive power from a first drive member to a second drive member, where the first drive member is on a drive side of the clutch device, and the second drive member is on the output side of the clutch device. An oil-delivering device is provided to oil the clutch, and the oiling of components on the output side of the clutch is provided. The oil-delivering device is arranged on the drive side of the clutch and delivers oil of an oil circuit serving the clutch device, or is immobilised, depending on an operating state. A clutch assembly of this type is known from DE 10 2008 002 844 A1. In a differential-free, clutch-controlled equalisation unit, a clutch assembly is provided with an activatable multiple disc clutch for a side shaft, which forms the shaft on the output side of the clutch device. Via the multiple disc clutch the drive power is directed to the connected drive wheel of a motor vehicle as required. The outer disc carrier of the multiple disc clutch, which is coupled to the drive-side shaft, delivers lubricating and cooling oil into an oil delivery pocket provided in a housing 16 of the clutch assembly, from which the oil flows back into a sump formed by the housing 16 , is picked up again by the clutch, and is fed back to the circuit. An inner oil circuit therefore forms of a disc pack of a side shaft clutch. Because of this inner oil circuit, a large proportion of the oil volume used for cooling and lubrication remains for a long time in the described inner oil circuit without the oil volume being sufficiently mixed with, or replaced with, “fresh” oil. The oil volume that has only just absorbed heat between the clutch discs is fed directly back to the discs. The clutch temperature therefore increases over-proportionately to the cooling effect that would be achievable with the oil quantity present in the equalisation unit. The over-proportionate heating of the clutches is disadvantageous in terms of the wear behaviour and thus the service life, as well as in terms of the response and control behaviour. A further disadvantage of the configuration disclosed in DE 10 2008 002 844 A1 is that the clutch packs of the side shaft clutches are in the oil continuously in order to pick it up and deliver it to the oil collection pocket. The associated splash losses increase the power loss of the drive train. With regard to the undesirable power loss, it is also the case, even in the case described in DE 10 2008 002 844 A1, in which the secondary part of the drive train is decoupled from the drive wheels and the side shaft clutches are completely open, that the secondary drive wheels roll on the road in driving mode and drag the inner disc carrier and the inner discs connected in a rotationally fixed manner thereto. The inner discs, however, are in constant contact with the oil, because they dip therein. Not only is the region of the extremely narrow air gap (gap width approximately 0.1 mm) between the inner and outer discs, which is situated directly in the oil, filled with oil, but the oil is also conveyed into an interspace, not in the oil, between the inner and outer discs of the multiple disc clutch by the rotating inner discs. The liquid friction or hydrodynamic friction produced as a result in turn transmits the drag torque acting on the inner discs from the secondary drive wheels to the outer discs, thereby driving the outer discs. However, as soon as the outer discs begin to rotate, they in turn convey oil into the above-described inner oil circuit and thus increase the oil volume conveyed, and again therefore increase the friction and power loss. The undesirable effect intensifies by itself to a certain extent. Experiments have shown that because of this effect the secondary drive train is not immobilised even when decoupled from the primary part of the drive train, in contrast to the assumptions made in DE 10 2008 002 844 A1. The negative consequences of this effect can be reduced only slightly by the low-friction design of the surfaces of the inner discs proposed in DE 10 2008 002 844 A1. Moreover, low-friction surfaces of the inner discs result in a much poorer response and control behaviour of the clutch pack. This disadvantage outweighs the power loss advantages that can be achieved with this measure. A further disadvantage of the clutch assembly disclosed in DE 10 2008 002 844 A1 is that the cooling and lubricating oil must pass through the inner disc carrier or another drive member on the output side of the clutch device. This makes said another drive member complicated to design. Given this background, a clutch assembly of the type mentioned in the introduction above, having a simplified design, and avoiding the above-described disadvantages is needed. In particular, it would be desirable to optimise the oiling concept described in DE 10 2008 002 844 A1 with regard to the power loss when a secondary part of the drive train is decoupled from a primary part of the drive train without compromising on response and control behaviour of the clutch packs, and without having a negative effect on the functionality of other components. It would further be desirable to ensure that the secondary axle drive train is completely immobilised when it is disconnected, and that components on the output side of the clutch device continue to be supplied with oil despite the oil-delivering device being in the non-delivering state. SUMMARY Accordingly, an oil-damming device is provided that can ensure lubrication of components arranged on the output side of the clutch device when the oil-delivering device does not deliver oil. Components arranged on the output side of the clutch device include components that are arranged in the oil circuit in an operating state in which the oil-delivering device delivers oil for the oil circuit, or are served by the oil provided by the oil circuit. An open rotary bearing may be provided, which is assigned an oil-damming device, which can ensure lubrication of the rotary bearing when the oil-delivering device does not deliver oil. Such an oil-damming device dams some of the delivered oil in a first operating state in which the oil-delivering device delivers oil. Further, in a second operating state in which the oil-delivering device no longer delivers oil because it has been immobilised, the oil-damming device makes the oil available to components that have been served by the oil provided by the oil-delivering device in the first operating state, and that still have a need for oiling after the oil-delivering device has been immobilised. This feature makes it possible to reduce or isolate the oil level of an oil reservoir from which the oil-delivering device is served from the components having a continuous oiling requirement, even in the second operating state. The open rotary bearing, by which in particular the output-side shaft or the output-side disc carrier is mounted on a housing, makes it possible to guide the oil flow of the oil circuit serving the clutch device through the open rotary bearing, and therefore to integrate the rotary bearing into the oil circuit. The rotary bearing is therefore also lubricated and cooled by the oil supplied to the clutch device. The necessity of guiding the oil flow for example through an inner disc carrier, the output-side shaft, or another drive member in particular on the output side of the clutch device—as disclosed in the prior art—no longer applies as a result. In addition, the use of an open rotary bearing results in minimisation of friction losses compared to a closed rotary bearing. The clutch assembly may be provided as an assembly of a clutch-controlled equalisation unit, with or without a differential, that forms part of an immobilisable secondary part of the overall drive train, as disclosed in DE 10 2008 002 844 A1. If the oil-delivering device is coupled to a drive member on the drive side of the clutch device, in particular to the shaft on the drive side of the clutch device or the drive-side disc carrier, the immobilisation of the secondary part of the drive train, which is effected by the opening of the clutch device, among other things, also results in the immobilisation of the oil-delivering device. This is desirable, because the power loss that would otherwise be caused by a continuously running oil-delivering device can be thereby avoided when the secondary part of the drive train is immobilised. Moreover, the clutch device, which is in a continuously open state when the secondary part of the drive train is immobilised, can thereby continue to run without losses if certain design requirements, explained below, are implemented. On the other hand, the interruption in oiling can result in problems with regard to the open rotary bearing. If the rotary bearing is a rotary bearing that is integrated into the oil circuit and bears an output-side drive member, as may be the case, the output-side drive member also rotates when the clutch device is open because the wheels rolling on the road drag the output-side drive members. There would therefore be the risk that the rotary bearing runs dry because of the interruption to the oil delivery as a result of the decoupling of the secondary drive train and the associated immobilisation of the oil-delivering device if an oil-damming device were not provided, which prevents the rotary bearing from running dry even when the oil-delivering device is not operating. The oil-damming device may be formed by an oil-damming ring having an oil-damming edge together with adjacent components, in particular wall inner sides of a housing in which the clutch assembly is mounted, forming a small oil sump in which the rotary bearing runs. The height of the oil-damming edge is dimensioned such that the oil level of the oil sump ensures sufficient lubrication of the rotary bearing even when the oil-delivering device is not operating. The cross section of the oil-damming device may be L-shaped. Coupling of the oil-delivering device to a drive member on the drive side of the clutch device can be made in different ways. Either the oil-delivering device is arranged directly on the drive-side drive member, as is the case, for example, when an oil-delivering wheel arranged directly on the drive-side shaft is used. Such an oil-delivering wheel can, for example, be formed by the crown wheel of the angular gear, the crown wheel being arranged on the crown wheel carrier shaft or intermediate shaft 8 forming the shaft on the drive side of the clutch device. Alternatively, the oil-delivering device may be driven indirectly, that is, with the interposition of further components that transmit the drive power necessary for the oil-delivering device from the drive-side drive member to the oil-delivering device. The oil-delivering device may be arranged at a distance from the clutch device, e.g., not formed directly by an outer disc carrier of a clutch device formed as a multiple disc clutch. The arrangement of the oil-delivering wheel at a distance from the clutch device means that the oil always flows into an oil sump of the equalisation unit at a distance from the clutch device after flowing through the clutch device to be oiled and before it is fed back into the oil circuit. This arrangement ensures sufficient mixing of the entire oil volume, and consequently obtains utilisation of a maximum cooling effect of the total quantity of oil at all times, which in turn reduces a thermal load on the clutch devices. This arrangement also ensures that the clutch device can run dry with the clutch open, and thus the secondary part of the drive train disconnected, whereby no clutch discs are continuously in the oil. Said configuration also makes it possible to configure the oil-delivering device, which can in particular be formed by an oil-delivering wheel arranged on a drive-side shaft, such that it can deliver the cooling and lubricating oil from an oil sump having an oil level below the clutch device. The clutch device, e.g., including the dragged clutch components, can thus be situated permanently above the oil level. Even components dragged continuously by the rolling drive wheels cause no friction losses, in particular no splash losses or losses owing to hydrodynamic effects, when the clutch is open, that is, when the secondary part is disconnected. The oil-delivering device may have an oil-delivering wheel that is formed by a crown wheel arranged on the drive-side shaft, by which, as a component of the angular gear, the drive power introduced by the Cardan shaft is transmitted to the shaft on the drive side of the clutch device. In particular, if the crown wheel itself may not have a sufficient diameter to dip into an oil sump situated below the clutch device owing to the dimensioning of the crown wheel, that is, it in particular has a smaller diameter than the outer disc carrier of the clutch device used. In this case, the oil-delivering wheel can comprise the crown wheel arranged on the drive-side shaft, the crown wheel being extended radially outwards, for example, by an oil-delivering ring additionally placed onto the crown wheel. This radial extension can be formed as an integral, single-piece component of the crown wheel. To reduce cost and/or weight, and to keep masses to be accelerated and braked low, the radial extension, in particular the oil-delivering ring, may be manufactured as a separate component using a lighter material, and to connect the oil-delivering ring to the crown wheel. It is not strictly necessary to realise the oil-delivering wheel with the aid of a gearwheel of the differential gear situated within the power flow. An oil-delivering wheel separate from the crown wheel can also be provided on the input shaft or intermediate shaft. Further disclosed herein is the use of an oil-damming device as described above and below in a clutch assembly forming part of a clutch-controlled equalisation unit with or without a differential, in which the rotary decoupling of the drive-side and output-side shaft is necessary for operation with an open clutch. For example, vehicles may have a clutch-controlled, differential-free equalisation unit instead of a conventional differential. Further, vehicles in which a secondary part of the drive train is provided for optional operation of the vehicle with all-wheel drive, where the secondary part of the drive train can be included in the flow of drive power optionally in what is known as disconnect operation, may be equipped with such an equalisation unit. An equalisation unit, the component of which may be the clutch assembly, can be either a transverse or a longitudinal equalisation unit. For example, a transverse equalisation unit may be used, e.g., a differential-free transverse equalisation unit operating purely frictionally, in which the side shafts of the drive wheels are coupled to the flow of drive power by side shaft clutches. Further, conventional longitudinal and transverse differentials operating in a form-fitting manner, in order to oil clutch packs of the differential locks, may be used. BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the presently disclosed subject matter can be found in the subclaims and the description of preferred exemplary embodiments using the drawings below. In the drawings, FIG. 1 shows a drive train construction having a continuously driven primary part and a secondary part that is only driven when required, and a differential-free equalisation unit (prior art), FIG. 2 shows a partial view of a clutch assembly for a drive train according to FIG. 1 in cross-section, and FIG. 3 shows a detail A from FIG. 2 . DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS FIG. 1 shows a drive train construction known from the prior art, having a continuously driven primary part and a secondary part that is only driven when required, the secondary part having a differential-free equalisation unit 1 for driving the secondary drive wheels 2 . The secondary part of the drive train, the drive members of which can be coupled to and disconnected from the primary part of the drive train depending on requirements, is shown cross-hatched, while the drive members that interact with the secondary part to transmit power during driving operation and rotate continuously are shown with solid black lines. The secondary part of the drive train should be completely immobilised after successful decoupling from the primary part of the drive train. The equalisation unit 1 is a differential-free equalisation unit, in which the flow of power is transmitted via two individually activatable clutch devices, formed by side shaft clutches 3 , and via the side shafts 4 , to the secondary drive wheels 2 . The side shaft clutches 3 , which are formed by frictionally operating multiple disc clutches, not only equalise the different rolling paths of the secondary axle drive wheels 2 during cornering, but are also used to actively influence dynamic driving behaviour. The clutches must be oiled with cooling and lubricating oil during operation. Experiments with the system shown in FIG. 1 have shown that, even if the secondary part of the drive train is decoupled from the primary part, in particular if it is decoupled during driving and at speeds upwards of approximately 50 km/h, the drive members of the secondary part, that is, the drive members on the drive side of the clutches 3 , are not immobilised as desired. Instead, these drive members continue to rotate owing to drag power introduced into the side shaft clutches 3 by the secondary drive wheels 2 , thus causing power loss. As described above, this power loss is attributable in particular to the oiling concept used in the prior art and the oil level necessary for it, with which the side shaft clutches are continuously in the oil even when the secondary drive train is decoupled. FIG. 2 shows a differential-free equalisation unit 1 , which may be provided for use in a drive train as shown in FIG. 1 , during operation with an oil-delivering device formed by a crown wheel 5 for oiling the clutch. When the secondary axle is connected, the crown wheel 5 scoops the oil owing to its rotation along a housing 16 inner wall to an oil collection pocket 6 provided in the housing. From there, it passes via oil supply channels 7 to the side shaft clutches 3 . The crown wheel 5 is arranged on the intermediate shaft 8 and is driven by a Cardan shaft (not shown). Compared to a solution in which the discs of the side shaft clutches primarily deliver the oil themselves, use of the crown wheel 5 as the oil-delivering device ensures that the oil flowing back from the clutches 3 collects in the oil sump and mixes with the overall oil volume before it is fed back to the oil circuit. A situation is avoided in which an inner oil circuit forms, as a result of which the oil is fed directly back to the clutches after having flowed through them, so that the oil would be over-proportionately heated as a result. It can also be seen in FIG. 2 that the oil level in the oil sump, indicated by the grey area, lies below the side shaft clutches 3 both in the operating state and when immobilised. This also contributes to minimizing power loss, because the clutch members dragged by the side shafts 4 are not in the oil, and thus cannot convey oil between the clutch discs. When the secondary part of the drive train is decoupled from the primary part, the clutches can therefore run completely dry and thus rotate in a friction-minimised manner. FIG. 3 shows the detail A indicated in FIG. 2 . A crown wheel 5 (see FIG. 2 ) arranged on an intermediate shaft 8 is driven in a known manner by a bevel wheel (not shown) driven by a Cardan shaft. The outer disc carrier 9 , which belongs to the clutch device 3 , and is the input side of the clutch 3 and therefore a drive-side drive member, is connected in a rotationally fixed manner to the intermediate shaft 8 , which is likewise a drive-side drive member. When the clutch is closed, the outer disc carrier 9 transmits the drive power via the outer discs of the clutch device 3 , which is configured as a multiple disc clutch, to the inner discs, via which the drive power is transmitted to the inner disc carrier 10 , which is an output-side drive member. The inner disc carrier 10 is in turn connected in a rotationally fixed manner to a side shaft 4 , a further output-side drive member. The drive power is transmitted to the secondary drive wheels 2 via the side shaft 4 , where necessary with the interposition of further drive members. When the clutch 3 is open, no forces are transmitted. As shown in FIGS. 2 and 3 , an oil-damming device 12 in the form of an oil-damming ring is provided in the region of an open rotary bearing 11 , with which the output-side drive members inner disc carrier 10 and side shaft 4 are mounted in a housing. The rotary bearing 11 is configured as an open rotary bearing and is integrated into the oil circuit, as can be seen by the arrows indicating the oil flow in FIGS. 2 and 3 . This means that the oil delivered by the oil-delivering device 5 is guided in a targeted manner through the open rotary bearing 11 . The inner disc carrier 10 and the side shaft 4 can as a result be configured without specific design measures that would allow the oil to flow through past a closed bearing. When the secondary axle is connected, that is, when the oil-delivering device 5 is delivering oil, the open rotary bearing 11 is lubricated by the oil flow, whereas when the secondary axle is decoupled, that is, when the drive members on the drive side of the clutch device are immobile, this oil flow is interrupted. The oil-damming device 12 ensures that, even when the secondary axle is decoupled, sufficient oil is available to the rotary bearing 11 for its lubrication, in that the device together with the adjacent components such as the housing 16 inner wall and the radial shaft sealing ring forms an oil sump. The dammed oil is symbolised by the grey area in FIGS. 2 and 3 . The cross section of the oil-damming device 12 may be formed, by way of example as a press-fit bush, and may be held in the housing next to the rotary bearing 11 , separated from the rotary bearing 11 only by an additional securing ring. This arrangement has the effect, owing to its configuration in the form of a horizontal “L” pointing inwards with its damming edge, that the lubrication of the open rotary bearing 11 is ensured even when the secondary part of the drive train is decoupled and the oil-delivering device 5 is immobilised owing to the operating state and does not deliver any oil. The cross section of the oil-damming device shown can of course vary as long as it ensures the desired oil-damming effect. The damming edge, which points inwards to the geometric rotation axis, can also have a further bend pointing outwards in the direction of the rotary bearing 11 or a corresponding kink, so that dammed oil can be kept better in the oil sump in the case of any centrifugal forces that occur. The oil-damming device 12 also serves as an oil-directing plate. The device 12 projects beyond the gap 13 formed between the housing and the disc carrier and thus guides the oil to radial bores 14 , which are provided in a web of the disc carrier 10 , when the secondary axle is connected. The oil is thus guided to the disc pack in a targeted manner. It can be distributed optimally in the disc pack and in particular does not penetrate, or only penetrates in insignificant amounts, into the said gap 13 , which would result in an excessive proportion of the oil flowing past the disc pack or being poorly distributed and as a result not participating optimally in the cooling and lubrication of the disc pack. The use of such an oil-directing plate is considered an independent invention regardless of whether the oil-directing plate also has an oil-damming function or not. In the drawings, the same reference numbers indicate the same elements. Further, some or all of these elements could be changed. Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent to those of skill in the art upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the arts discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation and is limited only by the following claims. All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.
The invention relates to a clutch assembly of a motor vehicle, in particular a clutch-controlled differential unit, comprising a switchable clutch apparatus that is able to transmit driving power from a drive element on the input side with regard to the clutch device to a drive element on the output side with regard to the clutch device, wherein an oil conveying apparatus is provided for the clutch oiling, which oil conveying apparatus conveys oil of an oil circuit serving the clutch device depending on the operating state. In order to ensure that the lubrication of components arranged on the output side with regard to the clutch device is ensured in operating states in which the oil conveying apparatus does not convey any oil, an oil accumulating device is provided.
Briefly summarize the main idea's components and working principles as described in the context.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to, and is a National Phase of, International Application No. PCT/EP2012/068873, filed on Sep. 25, 2012, which in turn claims priority to European Patent Application No. 11183508.8, filed on Sep. 30, 2011, which applications are hereby incorporated by reference in their entirety.", "BACKGROUND A clutch assembly of a motor vehicle transmits drive power to a wheel of an axle, and may include a clutch-controlled equalisation unit, having a clutch device.", "The equalization unit can be engaged and disengaged and can transmit drive power from a first drive member to a second drive member, where the first drive member is on a drive side of the clutch device, and the second drive member is on the output side of the clutch device.", "An oil-delivering device is provided to oil the clutch, and the oiling of components on the output side of the clutch is provided.", "The oil-delivering device is arranged on the drive side of the clutch and delivers oil of an oil circuit serving the clutch device, or is immobilised, depending on an operating state.", "A clutch assembly of this type is known from DE 10 2008 002 844 A1.", "In a differential-free, clutch-controlled equalisation unit, a clutch assembly is provided with an activatable multiple disc clutch for a side shaft, which forms the shaft on the output side of the clutch device.", "Via the multiple disc clutch the drive power is directed to the connected drive wheel of a motor vehicle as required.", "The outer disc carrier of the multiple disc clutch, which is coupled to the drive-side shaft, delivers lubricating and cooling oil into an oil delivery pocket provided in a housing 16 of the clutch assembly, from which the oil flows back into a sump formed by the housing 16 , is picked up again by the clutch, and is fed back to the circuit.", "An inner oil circuit therefore forms of a disc pack of a side shaft clutch.", "Because of this inner oil circuit, a large proportion of the oil volume used for cooling and lubrication remains for a long time in the described inner oil circuit without the oil volume being sufficiently mixed with, or replaced with, “fresh”", "oil.", "The oil volume that has only just absorbed heat between the clutch discs is fed directly back to the discs.", "The clutch temperature therefore increases over-proportionately to the cooling effect that would be achievable with the oil quantity present in the equalisation unit.", "The over-proportionate heating of the clutches is disadvantageous in terms of the wear behaviour and thus the service life, as well as in terms of the response and control behaviour.", "A further disadvantage of the configuration disclosed in DE 10 2008 002 844 A1 is that the clutch packs of the side shaft clutches are in the oil continuously in order to pick it up and deliver it to the oil collection pocket.", "The associated splash losses increase the power loss of the drive train.", "With regard to the undesirable power loss, it is also the case, even in the case described in DE 10 2008 002 844 A1, in which the secondary part of the drive train is decoupled from the drive wheels and the side shaft clutches are completely open, that the secondary drive wheels roll on the road in driving mode and drag the inner disc carrier and the inner discs connected in a rotationally fixed manner thereto.", "The inner discs, however, are in constant contact with the oil, because they dip therein.", "Not only is the region of the extremely narrow air gap (gap width approximately 0.1 mm) between the inner and outer discs, which is situated directly in the oil, filled with oil, but the oil is also conveyed into an interspace, not in the oil, between the inner and outer discs of the multiple disc clutch by the rotating inner discs.", "The liquid friction or hydrodynamic friction produced as a result in turn transmits the drag torque acting on the inner discs from the secondary drive wheels to the outer discs, thereby driving the outer discs.", "However, as soon as the outer discs begin to rotate, they in turn convey oil into the above-described inner oil circuit and thus increase the oil volume conveyed, and again therefore increase the friction and power loss.", "The undesirable effect intensifies by itself to a certain extent.", "Experiments have shown that because of this effect the secondary drive train is not immobilised even when decoupled from the primary part of the drive train, in contrast to the assumptions made in DE 10 2008 002 844 A1.", "The negative consequences of this effect can be reduced only slightly by the low-friction design of the surfaces of the inner discs proposed in DE 10 2008 002 844 A1.", "Moreover, low-friction surfaces of the inner discs result in a much poorer response and control behaviour of the clutch pack.", "This disadvantage outweighs the power loss advantages that can be achieved with this measure.", "A further disadvantage of the clutch assembly disclosed in DE 10 2008 002 844 A1 is that the cooling and lubricating oil must pass through the inner disc carrier or another drive member on the output side of the clutch device.", "This makes said another drive member complicated to design.", "Given this background, a clutch assembly of the type mentioned in the introduction above, having a simplified design, and avoiding the above-described disadvantages is needed.", "In particular, it would be desirable to optimise the oiling concept described in DE 10 2008 002 844 A1 with regard to the power loss when a secondary part of the drive train is decoupled from a primary part of the drive train without compromising on response and control behaviour of the clutch packs, and without having a negative effect on the functionality of other components.", "It would further be desirable to ensure that the secondary axle drive train is completely immobilised when it is disconnected, and that components on the output side of the clutch device continue to be supplied with oil despite the oil-delivering device being in the non-delivering state.", "SUMMARY Accordingly, an oil-damming device is provided that can ensure lubrication of components arranged on the output side of the clutch device when the oil-delivering device does not deliver oil.", "Components arranged on the output side of the clutch device include components that are arranged in the oil circuit in an operating state in which the oil-delivering device delivers oil for the oil circuit, or are served by the oil provided by the oil circuit.", "An open rotary bearing may be provided, which is assigned an oil-damming device, which can ensure lubrication of the rotary bearing when the oil-delivering device does not deliver oil.", "Such an oil-damming device dams some of the delivered oil in a first operating state in which the oil-delivering device delivers oil.", "Further, in a second operating state in which the oil-delivering device no longer delivers oil because it has been immobilised, the oil-damming device makes the oil available to components that have been served by the oil provided by the oil-delivering device in the first operating state, and that still have a need for oiling after the oil-delivering device has been immobilised.", "This feature makes it possible to reduce or isolate the oil level of an oil reservoir from which the oil-delivering device is served from the components having a continuous oiling requirement, even in the second operating state.", "The open rotary bearing, by which in particular the output-side shaft or the output-side disc carrier is mounted on a housing, makes it possible to guide the oil flow of the oil circuit serving the clutch device through the open rotary bearing, and therefore to integrate the rotary bearing into the oil circuit.", "The rotary bearing is therefore also lubricated and cooled by the oil supplied to the clutch device.", "The necessity of guiding the oil flow for example through an inner disc carrier, the output-side shaft, or another drive member in particular on the output side of the clutch device—as disclosed in the prior art—no longer applies as a result.", "In addition, the use of an open rotary bearing results in minimisation of friction losses compared to a closed rotary bearing.", "The clutch assembly may be provided as an assembly of a clutch-controlled equalisation unit, with or without a differential, that forms part of an immobilisable secondary part of the overall drive train, as disclosed in DE 10 2008 002 844 A1.", "If the oil-delivering device is coupled to a drive member on the drive side of the clutch device, in particular to the shaft on the drive side of the clutch device or the drive-side disc carrier, the immobilisation of the secondary part of the drive train, which is effected by the opening of the clutch device, among other things, also results in the immobilisation of the oil-delivering device.", "This is desirable, because the power loss that would otherwise be caused by a continuously running oil-delivering device can be thereby avoided when the secondary part of the drive train is immobilised.", "Moreover, the clutch device, which is in a continuously open state when the secondary part of the drive train is immobilised, can thereby continue to run without losses if certain design requirements, explained below, are implemented.", "On the other hand, the interruption in oiling can result in problems with regard to the open rotary bearing.", "If the rotary bearing is a rotary bearing that is integrated into the oil circuit and bears an output-side drive member, as may be the case, the output-side drive member also rotates when the clutch device is open because the wheels rolling on the road drag the output-side drive members.", "There would therefore be the risk that the rotary bearing runs dry because of the interruption to the oil delivery as a result of the decoupling of the secondary drive train and the associated immobilisation of the oil-delivering device if an oil-damming device were not provided, which prevents the rotary bearing from running dry even when the oil-delivering device is not operating.", "The oil-damming device may be formed by an oil-damming ring having an oil-damming edge together with adjacent components, in particular wall inner sides of a housing in which the clutch assembly is mounted, forming a small oil sump in which the rotary bearing runs.", "The height of the oil-damming edge is dimensioned such that the oil level of the oil sump ensures sufficient lubrication of the rotary bearing even when the oil-delivering device is not operating.", "The cross section of the oil-damming device may be L-shaped.", "Coupling of the oil-delivering device to a drive member on the drive side of the clutch device can be made in different ways.", "Either the oil-delivering device is arranged directly on the drive-side drive member, as is the case, for example, when an oil-delivering wheel arranged directly on the drive-side shaft is used.", "Such an oil-delivering wheel can, for example, be formed by the crown wheel of the angular gear, the crown wheel being arranged on the crown wheel carrier shaft or intermediate shaft 8 forming the shaft on the drive side of the clutch device.", "Alternatively, the oil-delivering device may be driven indirectly, that is, with the interposition of further components that transmit the drive power necessary for the oil-delivering device from the drive-side drive member to the oil-delivering device.", "The oil-delivering device may be arranged at a distance from the clutch device, e.g., not formed directly by an outer disc carrier of a clutch device formed as a multiple disc clutch.", "The arrangement of the oil-delivering wheel at a distance from the clutch device means that the oil always flows into an oil sump of the equalisation unit at a distance from the clutch device after flowing through the clutch device to be oiled and before it is fed back into the oil circuit.", "This arrangement ensures sufficient mixing of the entire oil volume, and consequently obtains utilisation of a maximum cooling effect of the total quantity of oil at all times, which in turn reduces a thermal load on the clutch devices.", "This arrangement also ensures that the clutch device can run dry with the clutch open, and thus the secondary part of the drive train disconnected, whereby no clutch discs are continuously in the oil.", "Said configuration also makes it possible to configure the oil-delivering device, which can in particular be formed by an oil-delivering wheel arranged on a drive-side shaft, such that it can deliver the cooling and lubricating oil from an oil sump having an oil level below the clutch device.", "The clutch device, e.g., including the dragged clutch components, can thus be situated permanently above the oil level.", "Even components dragged continuously by the rolling drive wheels cause no friction losses, in particular no splash losses or losses owing to hydrodynamic effects, when the clutch is open, that is, when the secondary part is disconnected.", "The oil-delivering device may have an oil-delivering wheel that is formed by a crown wheel arranged on the drive-side shaft, by which, as a component of the angular gear, the drive power introduced by the Cardan shaft is transmitted to the shaft on the drive side of the clutch device.", "In particular, if the crown wheel itself may not have a sufficient diameter to dip into an oil sump situated below the clutch device owing to the dimensioning of the crown wheel, that is, it in particular has a smaller diameter than the outer disc carrier of the clutch device used.", "In this case, the oil-delivering wheel can comprise the crown wheel arranged on the drive-side shaft, the crown wheel being extended radially outwards, for example, by an oil-delivering ring additionally placed onto the crown wheel.", "This radial extension can be formed as an integral, single-piece component of the crown wheel.", "To reduce cost and/or weight, and to keep masses to be accelerated and braked low, the radial extension, in particular the oil-delivering ring, may be manufactured as a separate component using a lighter material, and to connect the oil-delivering ring to the crown wheel.", "It is not strictly necessary to realise the oil-delivering wheel with the aid of a gearwheel of the differential gear situated within the power flow.", "An oil-delivering wheel separate from the crown wheel can also be provided on the input shaft or intermediate shaft.", "Further disclosed herein is the use of an oil-damming device as described above and below in a clutch assembly forming part of a clutch-controlled equalisation unit with or without a differential, in which the rotary decoupling of the drive-side and output-side shaft is necessary for operation with an open clutch.", "For example, vehicles may have a clutch-controlled, differential-free equalisation unit instead of a conventional differential.", "Further, vehicles in which a secondary part of the drive train is provided for optional operation of the vehicle with all-wheel drive, where the secondary part of the drive train can be included in the flow of drive power optionally in what is known as disconnect operation, may be equipped with such an equalisation unit.", "An equalisation unit, the component of which may be the clutch assembly, can be either a transverse or a longitudinal equalisation unit.", "For example, a transverse equalisation unit may be used, e.g., a differential-free transverse equalisation unit operating purely frictionally, in which the side shafts of the drive wheels are coupled to the flow of drive power by side shaft clutches.", "Further, conventional longitudinal and transverse differentials operating in a form-fitting manner, in order to oil clutch packs of the differential locks, may be used.", "BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the presently disclosed subject matter can be found in the subclaims and the description of preferred exemplary embodiments using the drawings below.", "In the drawings, FIG. 1 shows a drive train construction having a continuously driven primary part and a secondary part that is only driven when required, and a differential-free equalisation unit (prior art), FIG. 2 shows a partial view of a clutch assembly for a drive train according to FIG. 1 in cross-section, and FIG. 3 shows a detail A from FIG. 2 .", "DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS FIG. 1 shows a drive train construction known from the prior art, having a continuously driven primary part and a secondary part that is only driven when required, the secondary part having a differential-free equalisation unit 1 for driving the secondary drive wheels 2 .", "The secondary part of the drive train, the drive members of which can be coupled to and disconnected from the primary part of the drive train depending on requirements, is shown cross-hatched, while the drive members that interact with the secondary part to transmit power during driving operation and rotate continuously are shown with solid black lines.", "The secondary part of the drive train should be completely immobilised after successful decoupling from the primary part of the drive train.", "The equalisation unit 1 is a differential-free equalisation unit, in which the flow of power is transmitted via two individually activatable clutch devices, formed by side shaft clutches 3 , and via the side shafts 4 , to the secondary drive wheels 2 .", "The side shaft clutches 3 , which are formed by frictionally operating multiple disc clutches, not only equalise the different rolling paths of the secondary axle drive wheels 2 during cornering, but are also used to actively influence dynamic driving behaviour.", "The clutches must be oiled with cooling and lubricating oil during operation.", "Experiments with the system shown in FIG. 1 have shown that, even if the secondary part of the drive train is decoupled from the primary part, in particular if it is decoupled during driving and at speeds upwards of approximately 50 km/h, the drive members of the secondary part, that is, the drive members on the drive side of the clutches 3 , are not immobilised as desired.", "Instead, these drive members continue to rotate owing to drag power introduced into the side shaft clutches 3 by the secondary drive wheels 2 , thus causing power loss.", "As described above, this power loss is attributable in particular to the oiling concept used in the prior art and the oil level necessary for it, with which the side shaft clutches are continuously in the oil even when the secondary drive train is decoupled.", "FIG. 2 shows a differential-free equalisation unit 1 , which may be provided for use in a drive train as shown in FIG. 1 , during operation with an oil-delivering device formed by a crown wheel 5 for oiling the clutch.", "When the secondary axle is connected, the crown wheel 5 scoops the oil owing to its rotation along a housing 16 inner wall to an oil collection pocket 6 provided in the housing.", "From there, it passes via oil supply channels 7 to the side shaft clutches 3 .", "The crown wheel 5 is arranged on the intermediate shaft 8 and is driven by a Cardan shaft (not shown).", "Compared to a solution in which the discs of the side shaft clutches primarily deliver the oil themselves, use of the crown wheel 5 as the oil-delivering device ensures that the oil flowing back from the clutches 3 collects in the oil sump and mixes with the overall oil volume before it is fed back to the oil circuit.", "A situation is avoided in which an inner oil circuit forms, as a result of which the oil is fed directly back to the clutches after having flowed through them, so that the oil would be over-proportionately heated as a result.", "It can also be seen in FIG. 2 that the oil level in the oil sump, indicated by the grey area, lies below the side shaft clutches 3 both in the operating state and when immobilised.", "This also contributes to minimizing power loss, because the clutch members dragged by the side shafts 4 are not in the oil, and thus cannot convey oil between the clutch discs.", "When the secondary part of the drive train is decoupled from the primary part, the clutches can therefore run completely dry and thus rotate in a friction-minimised manner.", "FIG. 3 shows the detail A indicated in FIG. 2 .", "A crown wheel 5 (see FIG. 2 ) arranged on an intermediate shaft 8 is driven in a known manner by a bevel wheel (not shown) driven by a Cardan shaft.", "The outer disc carrier 9 , which belongs to the clutch device 3 , and is the input side of the clutch 3 and therefore a drive-side drive member, is connected in a rotationally fixed manner to the intermediate shaft 8 , which is likewise a drive-side drive member.", "When the clutch is closed, the outer disc carrier 9 transmits the drive power via the outer discs of the clutch device 3 , which is configured as a multiple disc clutch, to the inner discs, via which the drive power is transmitted to the inner disc carrier 10 , which is an output-side drive member.", "The inner disc carrier 10 is in turn connected in a rotationally fixed manner to a side shaft 4 , a further output-side drive member.", "The drive power is transmitted to the secondary drive wheels 2 via the side shaft 4 , where necessary with the interposition of further drive members.", "When the clutch 3 is open, no forces are transmitted.", "As shown in FIGS. 2 and 3 , an oil-damming device 12 in the form of an oil-damming ring is provided in the region of an open rotary bearing 11 , with which the output-side drive members inner disc carrier 10 and side shaft 4 are mounted in a housing.", "The rotary bearing 11 is configured as an open rotary bearing and is integrated into the oil circuit, as can be seen by the arrows indicating the oil flow in FIGS. 2 and 3 .", "This means that the oil delivered by the oil-delivering device 5 is guided in a targeted manner through the open rotary bearing 11 .", "The inner disc carrier 10 and the side shaft 4 can as a result be configured without specific design measures that would allow the oil to flow through past a closed bearing.", "When the secondary axle is connected, that is, when the oil-delivering device 5 is delivering oil, the open rotary bearing 11 is lubricated by the oil flow, whereas when the secondary axle is decoupled, that is, when the drive members on the drive side of the clutch device are immobile, this oil flow is interrupted.", "The oil-damming device 12 ensures that, even when the secondary axle is decoupled, sufficient oil is available to the rotary bearing 11 for its lubrication, in that the device together with the adjacent components such as the housing 16 inner wall and the radial shaft sealing ring forms an oil sump.", "The dammed oil is symbolised by the grey area in FIGS. 2 and 3 .", "The cross section of the oil-damming device 12 may be formed, by way of example as a press-fit bush, and may be held in the housing next to the rotary bearing 11 , separated from the rotary bearing 11 only by an additional securing ring.", "This arrangement has the effect, owing to its configuration in the form of a horizontal “L”", "pointing inwards with its damming edge, that the lubrication of the open rotary bearing 11 is ensured even when the secondary part of the drive train is decoupled and the oil-delivering device 5 is immobilised owing to the operating state and does not deliver any oil.", "The cross section of the oil-damming device shown can of course vary as long as it ensures the desired oil-damming effect.", "The damming edge, which points inwards to the geometric rotation axis, can also have a further bend pointing outwards in the direction of the rotary bearing 11 or a corresponding kink, so that dammed oil can be kept better in the oil sump in the case of any centrifugal forces that occur.", "The oil-damming device 12 also serves as an oil-directing plate.", "The device 12 projects beyond the gap 13 formed between the housing and the disc carrier and thus guides the oil to radial bores 14 , which are provided in a web of the disc carrier 10 , when the secondary axle is connected.", "The oil is thus guided to the disc pack in a targeted manner.", "It can be distributed optimally in the disc pack and in particular does not penetrate, or only penetrates in insignificant amounts, into the said gap 13 , which would result in an excessive proportion of the oil flowing past the disc pack or being poorly distributed and as a result not participating optimally in the cooling and lubrication of the disc pack.", "The use of such an oil-directing plate is considered an independent invention regardless of whether the oil-directing plate also has an oil-damming function or not.", "In the drawings, the same reference numbers indicate the same elements.", "Further, some or all of these elements could be changed.", "Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive.", "Many embodiments and applications other than the examples provided would be apparent to those of skill in the art upon reading the above description.", "The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.", "It is anticipated and intended that future developments will occur in the arts discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments.", "In sum, it should be understood that the invention is capable of modification and variation and is limited only by the following claims.", "All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary in made herein.", "In particular, use of the singular articles such as “a,” “the,” “said,” etc.", "should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary." ]
CROSS-REFERENCE TO RELATED U.S. PATENTS [0001] This application is based upon provisional application Serial No. 60/449,248, filed Feb. 20, 2003 and U.S. Ser. No. 10/353,390, filed Jan. 29, 2003, which is a continuation-in-part of U.S. Ser. No. 10/233,838, filed Aug. 30, 2002, and assigned to the same assignee, and related to U.S. Pat. Nos. 5,869,695; 5,886,194; 5,959,122; 5,994,385; and 6,025,501, also assigned to the same assignee as herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates to personal care compositions, and, particularly, to such compositions containing a mix of hair styling polymers and a compound or polymer having a carboxylic acid functionality, which impart the desirable physical attributes of toughness and cohesiveness, and a smooth feel, as well as high humidity curl retention, water-solubility and water-resistance. [0004] 2. Description of the Prior Art [0005] Hair styling polymers which feel stiff on hair are typically rather brittle under a high applied stress; accordingly, these polymers shatter easily when strained appreciably. On the other hand, highly flexible polymers will bend under both high and low stress but they are generally considered by the user to be too soft for desirable hair styling. [0006] In the aforementioned co-pending patent applications, and patents, polymers are described which have the desirable attributes of stiffness and flexibility, and have a strong affinity for hair, imparting a natural feel for the user, and are also water-soluble and water-resistant. These natural feel polymers can be easily removed from a substrate such as hair or skin, or a textile fiber, by simple washing. [0007] Accordingly, it is an object of this invention to provide improved personal care compositions containing polymers which exhibit toughness and cohesiveness. [0008] Another object is to provide hair care compositions made by mixing such polymers with a compound or polymer having a carboxylic acid functionality, which gives the blend the desired properties of excellent high humidity curl retention properties, water solubility and water-resistance. [0009] These and other objects and features of the invention will be made apparent from the following description thereof. IN THE DRAWINGS [0010] The FIGURE is a graphical representation of % Curl Retention vs % Carbomer® in compositions of the invention showing synergistic effect of components thereof. SUMMARY OF THE INVENTION [0011] The personal care compositions include polymers made by mixing (A), which are polymers having defined amounts of repeat units of (a) a monomer (e.g. α-olefin)-maleic anhydride alkyl half-ester or full acid, (b) maleamic acid, and (c) a maleimide, as shown below: [0012] where: [0013] R, R 1 , R 2 and R 3 are selected from H, alkyl, alkoxy, cycloalkyl, aryl, ester, acid, hydroxy, hydroxyalkyl, amido, amino, lactam, chloro, fluoro, halo and silyl, and R 4 is H or alkyl; and [0014] R′ is a derivatizing group selected from X, a hydrophobic amine; Y, a hydrophilic amine; and Z, a polyether amine; and suitable mixtures thereof; [0015] x, y and z are present, in mole %, of 0-99.9, 0-50 and 0.1-100, respectively; preferably 0-50, 0-5 and 50-100; and X, Y and Z preferably are present in mole ratios of 0-50:0-100:0-20; most preferably, 0-10:40-98:1-10; and [0016] (B) a compound or polymer with a carboxylic acid functionality. [0017] Typical hair care compositions herein are used in the modes of styling, mousse, gel and spray hair care products. These compositions performed well in practice giving the user the advantages of the natural feel polymers therein, particularly a firm and flexible characteristic, water-resistance and water-solubility, and excellent high humidity curl retention, and predetermined viscosity. DETAILED DESCRIPTION OF THE INVENTION [0018] The (A) polymer component of the polymers used in personal care compositions herein is particularly characterized by repeat units which contain an abundance (by weight) of an amine derivatizing group which can hydrogen-bond or ionically-bond with itself or other repeat units in the polymer forming intra- or inter-molecular bonds in the polymer. This results in a pseudo-network polymer. Cohesion between such hydrogen-bonded or ionically-bonded molecules provides the polymer with water-resistance, but also with water solubility because, once the polymer is flooded with water, it will admit sufficient amount of water for solubilization. These polymers show good adhesion to natural substrates but can be removed easily if desired. Some amine derivatizers may also crystallize upon dry-down, resulting in enhanced water resistance and physical properties. [0019] Representative structural components of the (A) polymers of the invention are given below. [0020] Polymer Backbone [0021] Monomer-Maleic Anhydride Copolymer [0022] Alkyl vinyl ether-maleic anhydride copolymer, e.g. methyl vinyl ether-maleic anhydride copolymer, or isobutyl vinyl ether-maleic anhydride copolymer, etc., alpha-olefin-maleic anhydride copolymer, e.g. ethylene-maleic anhydride copolymer, or isobutylene-maleic anhydride copolymer; styrene-maleic anhydride copolymer, etc., acrylate-maleic anhydride copolymer, e.g. acrylic acid-maleic anhydride copolymer, methyl methacrylate-maleic anhydride copolymer, etc., vinyl-maleic anhydride copolymer, e.g. vinyl chloride-maleic anhydride copolymer, vinyl pyrrolidone-maleic anhydride copolymer, etc., diene-maleic anhydride copolymer, e.g., butadiene-maleic anhydride copolymer, and derivatives thereof, and the like. [0023] Derivatizers [0024] Hydrophobic Amine (X) [0025] Monofunctional α-unsubstituted primary or secondary monoamines, unsubstituted or substituted with alkyl, aryl, heterocyclic, aromatic, fluoro, silyl amino, carboxy and halogen; e.g. C 1 -C 40 alkyl NH 2 ; butylamine, isobutyl amine, and octadecylamine. These amines may be included in the polymer to alter the solubility of the polymer. [0026] Hydrophilic Amine (Y) [0027] Hydroxy α-unsubstituted amines e.g. ethanolamine, isopropylamine, isopropanolamine, 3-amino-1-propanol; methoxyethyl amine, and diglycol amine; and alkyl diamines, e.g. 3-(dimethylamino)propylamine, N,N-dimethylethylenediamine, N-aminopropyl pyrrolidone, N-aminoethyl pyrrolidone, 1-(3-aminopropyl)imidazole and silicone amines. These amines are included in the polymer to modify the adhesive/cohesive balance in the polymer, and to increase compatibility with other components in system. [0028] Polyether Amine (Z) [0029] Polyoxyalkylene amine, having the formula: [0030] where R 5 and R 6 are selected from H and alkyl; e.g. R 5 is CH 3 and R 6 is H; and R 5 is CH 3 and R 6 is CH 3 ; and n and m are integers from 1-50; e.g. n=32 and m=10. These amines are obtainable as Jeffamine® M Monoamines (Huntsman Corp), with various molecular weights and ethylene oxide (EO)/propylene oxide (PO) ratios. These amines are present to provide natural feel properties in the polymer, i.e. softness and flexibility, as well as adhesive/cohesive balance and to modify solubility. [0031] The personal care compositions herein are made by mixing (A) with (B), a compound or polymer having a carboxylic acid functionality. Carboxylic acid functionality includes the free acid and the neutralized acid. A particularly preferred (B) polymer is a linear or crosslinked acrylic acid polymer, e.g. Carbopol®, preferably which is neutralized before mixing with (A). The result of mixing (A) and (B) is a complexed, synergistic product particularly suitable for hair care application because it has high humidity curl retention, and may have an increased solution viscosity, as compared to (A) or (B) alone. The viscosity of the product can be predetermined by the relative amounts of (a), (b) and (c) in polymer (A). For example, 100 mole % in the (c) repeat unit will provide an opaque, more viscous, product, while dilution of the polymer with more (a) repeat units will form a more desirable clear, and less viscous product, upon mixing with (B). [0032] The polymers strongly interact and upon dry down result in films with increased toughness and cohesiveness than individual polymer systems. [0033] When these synergistic systems are used in a personal care hair styling application the resultant formulations have improved high humidity and curl retention (HHCR) when compared to similar formulations containing the individual polymers alone. [0034] The degree of complexation between (A) and (B) can be predetermined by adjusting the mole ratio of maleimide in (A) to the carboxylic units in (B). Complexation is strongest for products in which the maleimide:carboxylic mole ratio approaches 1:1. [0035] However, complexation is not as pH sensitive as typical acid-base complexed systems, e.g. PVP and acrylic acid; in fact, complexation can occur at a neutral pH. Thus personal care formulations at or around a neutral pH still possess synergistic complexation complexation of (A) and (B), with its resultant desirable properties and physical attributes. [0036] Referring to the FIGURE, there is shown a dramatic increase in HHCR which is evident for the 50:50 blend of (A) with Carbomer® 940 (B). The actual experimental value of 75.2% curl retention after 4 hours is much higher than the calculated value of 52.4% which is expected if the interaction of the two polymers had merely an additive effect. [0037] The invention will now be described with reference to the following examples. EXAMPLE 1 Step 1 Preparation of Polymer (A) [0038] The following were charged into a 2-liter, stainless steel high pressure reactor. P(maleic anhydride/isobutene) (Man) 72.94 g 3-(dimethylamino) propylamine (50 mol % based on Man) 24.17 g Jeffamine ® M-2070 (2 mol % based on Man) 20.73 g (M.W. 2,000, 70/30 EO/PO) (water soluble) Triethylamine (43 mol % based on Man) (Neutralizer) 20.59 g Methanol 257.07 g  [0039] The reactor was sealed, purged 3 times with N 2 gas, and heating was begun according to the following heating profile. Ambient →  90° C., 1♯1/2♭ hr.  90° C. →  90° C., 2 hr.  90° C. → 130° C., 1½ hr. 130° C. → 130° C., 8 hr. 130° C. →  35° C., 1 hr. [0040] At the end of the heating cycle, the polymer product was obtained as a lightly viscous, yellow, clear solution; then it was flooded with water to give a viscous, hazy, yellow-colored solution. Step 2 Mixing Polymer (A) with Carboxylic Acid Containing Polymer (B) [0041] The polymer solution (A) was mixed with neutralized Carbopol®, a crosslinked acrylic acid polymer, in amounts of 2 and 0.5 wt. %, respectively, and in an amount present in a typical styling gel formulation. A thick gel having a viscosity greater than (A) or (B) was obtained after an hour. The gel formulation was applied to hair and the resultant film was stressed. The film showed a natural feel, combining firm and flexible characteristics, water-resistance and water-solubility, and excellent high humidity curl retention. EXAMPLE 2 Step 1 [0042] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g  Dimethylaminopropylamine 39.51 g Jeffamine M-2005 42.35 g (M.W. 2,000, 5/95 EO/PO (water-insoluble) Jeffamine M-2070 42.35 g (M.W. 2,000, 70/30 EO/PO (water-soluble) Triethylamine 31.30 g Ethanol 510.20 g  [0043] The reactor was sealed and purged with an inert gas. The following heating profile was initiated: Heat to 125° C.  4 hours Hold at 125° C. 12 hours Cool to 35° C.  1 hour [0044] After the heating profile was complete, the polymer solution was discharged from the reactor. The resultant material was a viscous, clear yellow solution. This material was laid down as a film and allowed to dry. A non-brittle film resulted which was water soluble. Exchanging ethanol for water gave a water-based polymer solution having similar properties to the ethanol-based material. Step 2 [0045] This step was carried out as in Example 1 to provide similar results. EXAMPLE 3 Step 1 [0046] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g  Dimethylaminopropylamine 39.51 g Jeffamine M-2005 84.70 g Triethylamine 31.30 g Ethanol 510.20 g  [0047] The reactor was sealed and purged with an inert gas. The following heating profile was initiated: Heat to 125° C.  4 hours Hold at 125° C. 12 hours Cool to 35° C.  1 hour [0048] After the heating profile was complete, the polymer solution was discharged from the reactor. The resultant product was a viscous, clear yellow solution. This material was laid down as a film and allowed to dry. A non-brittle film resulted. Exchanging with water gave a water-based polymer solution having similar properties to the ethanol-based material. Step 2 [0049] This step was carried out as in Example 1 to provide similar results. EXAMPLE 4 Step 1 [0050] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g  Dimethylaminopropylamine 39.51 g Jeffamine M-2005 84.70 g Jeffamine M-2070 33.90 g Triethylamine 31.30 g Ethanol 573.17 g  [0051] The reactor was sealed and purged with an inert gas. The following heating profile was initiated: Heat to 125° C.  4 hours Hold at 125° C. 12 hours Cool to 35° C.  1 hour [0052] After the heating profile was complete, the polymer solution was discharged from the reactor. The resultant material was a viscous clear yellow solution. This material, when laid down as a film and allowed to dry, resulted in a flexible film. This same material can be exchanged with water to give a water-based polymer solution having similar properties to the ethanol-based material. Step 2 [0053] This step was carried out as in Example 1 to provide similar results. EXAMPLE 5 Step 1 [0054] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g  Dimethylaminopropylamine 39.51 g Jeffamine M-2005 101.70 g  Jeffamine M-2070 84.70 g Triethylamine 31.30 g Ethanol 699.08 g  [0055] The reactor was sealed and purged with an inert gas. The following heating profile was initiated: Heat to 125° C.  4 hours Hold at 125° C. 12 hours Cool to 35° C.  1 hour [0056] After the heating profile was complete, the polymer solution was discharged from the reactor. The resultant material was a viscous clear yellow solution. This material, when laid down as a film and allowed to dry, resulted in a very flexible film. This same material can be exchanged with water to give a water-based polymer solution having similar properties to the ethanol-based material. Step 2 [0057] This step was carried out as in Example 1 to provide similar results. [0058] The compositions herein are particularly useful in products for personal care, including, but not limited to, gels, lotions, mousses, sprays, fixatives, shampoos, conditioners, 2-1 shampoos, temporary hair dyes, semi-permanent hair dyes, permanent hair dyes, straighteners, permanent waves, relaxers, creams, putties, waxes and pomades. The compositions can be used alone or in combination with anionic, nonionic and cationic hair styling polymers, thickeners, film formers, surfactants, reducing agents, oxidizers and other ingredients typically found in personal care products. Specific examples follow: [0059] Gels: [0060] Hair and/or skin care compositions wherein the compositions comprise an aqueous or hydroalcoholic gel. Gels can be in the form of spray gels, fluid gels, tube gels and thick viscous tub gels. The compositions are preferably employed at use levels of 0.1-10% by weight in anionic, nonionic or cationic gellants, or combinations thereof, such gallants preferably being present in amounts of 0.1-5% by weight. [0061] Anionic gellants include, but are not limited to, Carbomer®, acrylates/C10-30 alkyl acrylate crosspolymer, acrylates copolymer, acrylates/beheneth-25 methacrylate copolymer, acylates/steareth-20 methacrylate copolymer, polyvinylmethyl ether/maleic anhydride PVM/MA, alkyldiene, e.g. decadiene or octadiene crosspolymer, xanthan gum, sodium polyacrylate, polyacrylamide, copolymers of sodium acrylates, and copolymers of polyacrylamide. [0062] Nonionic gellants include, but are not limited to, guar and their derivatives, and celluloses and their derivatives. Examples are hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, hydroxypropylmethyl cellulose and hydroxypropyl guar. [0063] Cationic thickeners include, but are not limited to, Polyquaternium 32 (and) mineral oil, and Polyquaternium 37 (and) mineral oil (and) PPG-1 Trideceth-6. [0064] Hair and skin care gel formulations with the compositions herein using crosslinked homopolymers of acrylic acid, e.g., Carbomer® and/or acrylates/C10-30 alkyl acrylate crosspolymer as the gellant result in synergistic performance in moisture resistance. In particular, hair styling gels with the above listed combinations show synergistic high humidity resistance on hair. [0065] The complexation of the compositions with Carbomer® and/or acrylates/C10-30 alkyl acrylate crosspolymer results in clear films upon draw down. The resultant viscosity, yield value and suspension capabilities are unaffected or increased by the addition of such compositions into the gellant. FORMULATION EXAMPLES (% by wt) [0066] Hair Styling Gel Formulation 1 [0067] Water—QS to 100% [0068] Carbomer®-0.5 [0069] Triethanolamine (99%)—0.5 [0070] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0071] Maleimide/maleic acid copolymer (30%)—6.66 [0072] Benzophenone-4—0.05 [0073] Disodium EDTA—0.10 [0074] Triethanolamine (99%)—adjust to pH 7 [0075] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0076] Hair Styling Gel Formulation 2 [0077] Water—QS to 100% [0078] Isoceteth-20—0.5 [0079] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0080] Maleimide/maleic acid copolymer (30%)-6.66 [0081] Aminomethyl propanol—0.25 [0082] Acrylates/beheneth-25 methacrylate copolymer (20%)—4.7 [0083] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0084] Hair Styling Cream [0085] Water—QS to 100% [0086] Sodium polyacrylate (and) hydrogenated polydecene (and) trideceth-6—2.0 [0087] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer (30%)-6.7 [0088] Glycerin—2.0 [0089] Cetyl PEG/PPG-15/15 butyl ether dimethicone—1.0 [0090] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0091] Mousses: [0092] The compositions are incorporated into aerosol and non-aerosol hair and skin mousse formulations, as well as spray mousses which utilize an aerosol valve with a dip tube and a mechanical break-up actuator to deliver an atomized spray foam. They are also compatible in aerosol and non-aerosol shave foam applications. Preferred use levels of the active polymer mixture are 0.1-10.0% by weight. [0093] Shampoos and Body Washes: [0094] The compositions are compatible with anionic, amphoteric, cationic and nonionic surfactants. The compositions are incorporated into cleansing formulations for hair and body. The compositions are used at polymer use levels of 0.1 to 10% by weight with anionic, amphoteric, cationic, and nonionic surfactants, or combinations thereof, such surfactants preferably being present in amounts of 0.1 to 20% by weight. [0095] Clear Shampoo Formulation: [0096] Water—QS to 100% [0097] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer—5.0 [0098] Cocamidopropyl betaine (34.5%)—10.00 [0099] Cocoamphodiacetate (50%)-5.00 [0100] Sodium laureth sulfate (25.6)-17.5 [0101] Ammonium lauryl sulfate (29.2%)—17.5 [0102] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.30 [0103] Citric Acid—0.25 [0104] Oil-in-Water Emulsions and Hair Conditioners: [0105] The compositions are incorporated in hair and skin oil-in-water emulsions. In hair conditioners, the polymer mixtures are compatible with quaternary ammonium compounds. The use level of surfactants/emulsifiers suitably is from 0.1 to 10% by weight. [0106] Conditioner Formulation: [0107] Phase A: [0108] Water—QS to 100% [0109] Citric Acid—0.25 [0110] Hydroxyethyl cellulose—0.5 [0111] Disodium EDTA—0.1 [0112] Phase B: [0113] Cetearyl Alcohol—4.0 [0114] Steareth-10—1.0 [0115] Glyceryl stearate (and) PEG-100 stearate—2.5 [0116] Dicetyldimonium chloride (68.2%)-2.0 [0117] Phase C: [0118] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer (30%)—6.6 [0119] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0120] Wheat amino acid—0.5 [0121] Process: [0122] Heat Phases A and B separately to 75° C. Add Phase B to Phase A with agitation. Mix until uniform and cool to 45° C. Continue mixing and add ingredients in Phase C one at a time with mixing until homogenous. [0123] Oxidative Hair Dyes: [0124] The polymers are incorporated into oxidative hair dye formulations including semi-permanent and permanent hair dye products, suitably at use levels of 0.1-10% by weight. [0125] Formulation: [0126] Water—QS to 100% [0127] Oleic acid—5 [0128] C11-15 pareth-9—3 [0129] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0130] maleimide/maleic acid copolymer (30%)—3.0 [0131] Ammonium hydroxide—2 [0132] Steareth-21—2 [0133] Propylene glycol— 2 [0134] Cetyl alcohol— 2 [0135] PEG150/Stearyl/SMDI copolymer—3 [0136] Stearyl alcohol—1 [0137] Sodium sulfite—1 [0138] Iron oxides—0.5 [0139] Mica—0.2 [0140] 1-Naphitol—0.2 [0141] p-Phenylenediamine—0.2 [0142] Titanium dioxide—0.1 [0143] Relaxers and Permanent Waves: [0144] The compositions are used as relaxer and permanent wave formulations, suitably in amounts of 0.1%-10% by weight. They may be combined with hair reducing agents, including, but not limited to, ammonium thioglycolate, guanidine hydroxide, sodium bisulfite and the like. [0145] Formulation: [0146] Crème Hair Relaxer Base: To be mixed with guanidine carbonate [0147] Activator Solution [0148] Water—QS to 100% [0149] Petrolatum—10 [0150] Paraffin Wax—8 [0151] Mineral oil—6 [0152] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0153] maleimide/maleic acid copolymer (30%)—5.0 [0154] Cetearyl alcohol—3 [0155] Calcium hydroxide—3 [0156] Polysorbate 80—2 [0157] Laneth-15—2 [0158] PEG-75 lanolin oil—1 [0159] Cocamphodipropionate—1 [0160] Hair Sprays: [0161] The compositions are formulated as hair sprays, both non-aerosol and aerosol, suitably at use levels of 0.1-10% by weight. Aerosol hair sprays can include up to 60% hydrocarbon, 70% dimethyl ether, 50% hydrofluorocarbon 152a, or combinations thereof. Hair spray formulations include, but are not limited to, alcohol-free pump hair sprays, 55%-95% VOC pump and aerosol hair sprays. [0162] Formulation: [0163] Clear Alcohol Free Pump Hair Spray [0164] Water—QS to 100% [0165] Sodium lauryl sulfate (25%)—0.25 [0166] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0167] maleimide/maleic acid copolymer (30%)—13.33 [0168] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl [0169] butylcarbamate—0.5 [0170] Pump—Calmar Marks VI WL-31 [0171] Personal Care Applications: [0172] The compositions are blended with anionic, nonionic and cationic hair styling polymers, thickeners, and film formers; and with anionic, nonionic and cationic surfactants. Clarity in water is increased with low levels of charged surfactants (0.1-2% by weight). [0173] The compositions also are formulated into bodifying leave-on and rinse-off hair preparations. They also can be formulated into flexible hold styling products which provide smooth, continuous films on hair that have strength and will bend under both high and low stress. [0174] Skin Care Applications: [0175] The compositions are used as a film former (a) for the enhancement of antiperspirants to either increase overall wetness protection or to effect a reduction in the amount of conventional actives therein while holding equivalent efficacy; (b) to increase the substantivity of a deodorant active for better and longer acting deodorancy; (c) in an anti-bacterial liquid hand soap to increase efficacy and for longer lasting claim; (d) for holding products on skin; (e) to increase contact time of a therapeutic skin product containing an active, including, but not limited to, Betulin, Vitamins E, A and C, ceramides, allantoin, lycopenes, bisabolol, retinol, and the like, and (f) to aid in the removal of sebum, and/or villous hair. [0176] The compositions also are used in make-up products, e.g. foundation, mascara, bronzers, eyeliners, to effect film formation, wear resistance and pigment dispersion. They are also used in mascaras for curl retention. [0177] While the invention has been described with particular reference to certain embodiments thereof, it will be understood that changes and modifications may be made which are within the skill of the art. Accordingly, it is intended to be bound only by the following claims, in which:
Personal care compositions, particularly hair care products, include a polymer mixture made from (A) a derivatized polymer of maleic anhydride having defined repeat units of a monomer (e.g. α-olefin) maleic anhydride alkyl half-ester or full acid, maleamic acid and maleimide, and (B) a compound or polymer having a carboxylic acid functionality. These compositions exhibit excellent high humidity curl retention properties, as well as an advantageous blend of toughness and cohesiveness, and a strong affinity to natural fibers such as keratin-based fibers, e.g. hair, skin, or textiles, such as cotton or wool; and they are also water-soluble and water-resistant.
Summarize the patent document, focusing on the invention's functionality and advantages.
[ "CROSS-REFERENCE TO RELATED U.S. PATENTS [0001] This application is based upon provisional application Serial No. 60/449,248, filed Feb. 20, 2003 and U.S. Ser.", "No. 10/353,390, filed Jan. 29, 2003, which is a continuation-in-part of U.S. Ser.", "No. 10/233,838, filed Aug. 30, 2002, and assigned to the same assignee, and related to U.S. Pat. Nos. 5,869,695;", "5,886,194;", "5,959,122;", "5,994,385;", "and 6,025,501, also assigned to the same assignee as herein.", "BACKGROUND OF THE INVENTION [0002] 1.", "Field of the Invention [0003] This invention relates to personal care compositions, and, particularly, to such compositions containing a mix of hair styling polymers and a compound or polymer having a carboxylic acid functionality, which impart the desirable physical attributes of toughness and cohesiveness, and a smooth feel, as well as high humidity curl retention, water-solubility and water-resistance.", "[0004] 2.", "Description of the Prior Art [0005] Hair styling polymers which feel stiff on hair are typically rather brittle under a high applied stress;", "accordingly, these polymers shatter easily when strained appreciably.", "On the other hand, highly flexible polymers will bend under both high and low stress but they are generally considered by the user to be too soft for desirable hair styling.", "[0006] In the aforementioned co-pending patent applications, and patents, polymers are described which have the desirable attributes of stiffness and flexibility, and have a strong affinity for hair, imparting a natural feel for the user, and are also water-soluble and water-resistant.", "These natural feel polymers can be easily removed from a substrate such as hair or skin, or a textile fiber, by simple washing.", "[0007] Accordingly, it is an object of this invention to provide improved personal care compositions containing polymers which exhibit toughness and cohesiveness.", "[0008] Another object is to provide hair care compositions made by mixing such polymers with a compound or polymer having a carboxylic acid functionality, which gives the blend the desired properties of excellent high humidity curl retention properties, water solubility and water-resistance.", "[0009] These and other objects and features of the invention will be made apparent from the following description thereof.", "IN THE DRAWINGS [0010] The FIGURE is a graphical representation of % Curl Retention vs % Carbomer® in compositions of the invention showing synergistic effect of components thereof.", "SUMMARY OF THE INVENTION [0011] The personal care compositions include polymers made by mixing (A), which are polymers having defined amounts of repeat units of (a) a monomer (e.g. α-olefin)-maleic anhydride alkyl half-ester or full acid, (b) maleamic acid, and (c) a maleimide, as shown below: [0012] where: [0013] R, R 1 , R 2 and R 3 are selected from H, alkyl, alkoxy, cycloalkyl, aryl, ester, acid, hydroxy, hydroxyalkyl, amido, amino, lactam, chloro, fluoro, halo and silyl, and R 4 is H or alkyl;", "and [0014] R′ is a derivatizing group selected from X, a hydrophobic amine;", "Y, a hydrophilic amine;", "and Z, a polyether amine;", "and suitable mixtures thereof;", "[0015] x, y and z are present, in mole %, of 0-99.9, 0-50 and 0.1-100, respectively;", "preferably 0-50, 0-5 and 50-100;", "and X, Y and Z preferably are present in mole ratios of 0-50:0-100:0-20;", "most preferably, 0-10:40-98:1-10;", "and [0016] (B) a compound or polymer with a carboxylic acid functionality.", "[0017] Typical hair care compositions herein are used in the modes of styling, mousse, gel and spray hair care products.", "These compositions performed well in practice giving the user the advantages of the natural feel polymers therein, particularly a firm and flexible characteristic, water-resistance and water-solubility, and excellent high humidity curl retention, and predetermined viscosity.", "DETAILED DESCRIPTION OF THE INVENTION [0018] The (A) polymer component of the polymers used in personal care compositions herein is particularly characterized by repeat units which contain an abundance (by weight) of an amine derivatizing group which can hydrogen-bond or ionically-bond with itself or other repeat units in the polymer forming intra- or inter-molecular bonds in the polymer.", "This results in a pseudo-network polymer.", "Cohesion between such hydrogen-bonded or ionically-bonded molecules provides the polymer with water-resistance, but also with water solubility because, once the polymer is flooded with water, it will admit sufficient amount of water for solubilization.", "These polymers show good adhesion to natural substrates but can be removed easily if desired.", "Some amine derivatizers may also crystallize upon dry-down, resulting in enhanced water resistance and physical properties.", "[0019] Representative structural components of the (A) polymers of the invention are given below.", "[0020] Polymer Backbone [0021] Monomer-Maleic Anhydride Copolymer [0022] Alkyl vinyl ether-maleic anhydride copolymer, e.g. methyl vinyl ether-maleic anhydride copolymer, or isobutyl vinyl ether-maleic anhydride copolymer, etc.", ", alpha-olefin-maleic anhydride copolymer, e.g. ethylene-maleic anhydride copolymer, or isobutylene-maleic anhydride copolymer;", "styrene-maleic anhydride copolymer, etc.", ", acrylate-maleic anhydride copolymer, e.g. acrylic acid-maleic anhydride copolymer, methyl methacrylate-maleic anhydride copolymer, etc.", ", vinyl-maleic anhydride copolymer, e.g. vinyl chloride-maleic anhydride copolymer, vinyl pyrrolidone-maleic anhydride copolymer, etc.", ", diene-maleic anhydride copolymer, e.g., butadiene-maleic anhydride copolymer, and derivatives thereof, and the like.", "[0023] Derivatizers [0024] Hydrophobic Amine (X) [0025] Monofunctional α-unsubstituted primary or secondary monoamines, unsubstituted or substituted with alkyl, aryl, heterocyclic, aromatic, fluoro, silyl amino, carboxy and halogen;", "e.g. C 1 -C 40 alkyl NH 2 ;", "butylamine, isobutyl amine, and octadecylamine.", "These amines may be included in the polymer to alter the solubility of the polymer.", "[0026] Hydrophilic Amine (Y) [0027] Hydroxy α-unsubstituted amines e.g. ethanolamine, isopropylamine, isopropanolamine, 3-amino-1-propanol;", "methoxyethyl amine, and diglycol amine;", "and alkyl diamines, e.g. 3-(dimethylamino)propylamine, N,N-dimethylethylenediamine, N-aminopropyl pyrrolidone, N-aminoethyl pyrrolidone, 1-(3-aminopropyl)imidazole and silicone amines.", "These amines are included in the polymer to modify the adhesive/cohesive balance in the polymer, and to increase compatibility with other components in system.", "[0028] Polyether Amine (Z) [0029] Polyoxyalkylene amine, having the formula: [0030] where R 5 and R 6 are selected from H and alkyl;", "e.g. R 5 is CH 3 and R 6 is H;", "and R 5 is CH 3 and R 6 is CH 3 ;", "and n and m are integers from 1-50;", "e.g. n=32 and m=10.", "These amines are obtainable as Jeffamine® M Monoamines (Huntsman Corp), with various molecular weights and ethylene oxide (EO)/propylene oxide (PO) ratios.", "These amines are present to provide natural feel properties in the polymer, i.e. softness and flexibility, as well as adhesive/cohesive balance and to modify solubility.", "[0031] The personal care compositions herein are made by mixing (A) with (B), a compound or polymer having a carboxylic acid functionality.", "Carboxylic acid functionality includes the free acid and the neutralized acid.", "A particularly preferred (B) polymer is a linear or crosslinked acrylic acid polymer, e.g. Carbopol®, preferably which is neutralized before mixing with (A).", "The result of mixing (A) and (B) is a complexed, synergistic product particularly suitable for hair care application because it has high humidity curl retention, and may have an increased solution viscosity, as compared to (A) or (B) alone.", "The viscosity of the product can be predetermined by the relative amounts of (a), (b) and (c) in polymer (A).", "For example, 100 mole % in the (c) repeat unit will provide an opaque, more viscous, product, while dilution of the polymer with more (a) repeat units will form a more desirable clear, and less viscous product, upon mixing with (B).", "[0032] The polymers strongly interact and upon dry down result in films with increased toughness and cohesiveness than individual polymer systems.", "[0033] When these synergistic systems are used in a personal care hair styling application the resultant formulations have improved high humidity and curl retention (HHCR) when compared to similar formulations containing the individual polymers alone.", "[0034] The degree of complexation between (A) and (B) can be predetermined by adjusting the mole ratio of maleimide in (A) to the carboxylic units in (B).", "Complexation is strongest for products in which the maleimide:carboxylic mole ratio approaches 1:1.", "[0035] However, complexation is not as pH sensitive as typical acid-base complexed systems, e.g. PVP and acrylic acid;", "in fact, complexation can occur at a neutral pH.", "Thus personal care formulations at or around a neutral pH still possess synergistic complexation complexation of (A) and (B), with its resultant desirable properties and physical attributes.", "[0036] Referring to the FIGURE, there is shown a dramatic increase in HHCR which is evident for the 50:50 blend of (A) with Carbomer® 940 (B).", "The actual experimental value of 75.2% curl retention after 4 hours is much higher than the calculated value of 52.4% which is expected if the interaction of the two polymers had merely an additive effect.", "[0037] The invention will now be described with reference to the following examples.", "EXAMPLE 1 Step 1 Preparation of Polymer (A) [0038] The following were charged into a 2-liter, stainless steel high pressure reactor.", "P(maleic anhydride/isobutene) (Man) 72.94 g 3-(dimethylamino) propylamine (50 mol % based on Man) 24.17 g Jeffamine ® M-2070 (2 mol % based on Man) 20.73 g (M.W. 2,000, 70/30 EO/PO) (water soluble) Triethylamine (43 mol % based on Man) (Neutralizer) 20.59 g Methanol 257.07 g [0039] The reactor was sealed, purged 3 times with N 2 gas, and heating was begun according to the following heating profile.", "Ambient → 90° C., 1♯1/2♭ hr.", "90° C. → 90° C., 2 hr.", "90° C. → 130° C., 1½ hr.", "130° C. → 130° C., 8 hr.", "130° C. → 35° C., 1 hr.", "[0040] At the end of the heating cycle, the polymer product was obtained as a lightly viscous, yellow, clear solution;", "then it was flooded with water to give a viscous, hazy, yellow-colored solution.", "Step 2 Mixing Polymer (A) with Carboxylic Acid Containing Polymer (B) [0041] The polymer solution (A) was mixed with neutralized Carbopol®, a crosslinked acrylic acid polymer, in amounts of 2 and 0.5 wt.", "%, respectively, and in an amount present in a typical styling gel formulation.", "A thick gel having a viscosity greater than (A) or (B) was obtained after an hour.", "The gel formulation was applied to hair and the resultant film was stressed.", "The film showed a natural feel, combining firm and flexible characteristics, water-resistance and water-solubility, and excellent high humidity curl retention.", "EXAMPLE 2 Step 1 [0042] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g Dimethylaminopropylamine 39.51 g Jeffamine M-2005 42.35 g (M.W. 2,000, 5/95 EO/PO (water-insoluble) Jeffamine M-2070 42.35 g (M.W. 2,000, 70/30 EO/PO (water-soluble) Triethylamine 31.30 g Ethanol 510.20 g [0043] The reactor was sealed and purged with an inert gas.", "The following heating profile was initiated: Heat to 125° C. 4 hours Hold at 125° C. 12 hours Cool to 35° C. 1 hour [0044] After the heating profile was complete, the polymer solution was discharged from the reactor.", "The resultant material was a viscous, clear yellow solution.", "This material was laid down as a film and allowed to dry.", "A non-brittle film resulted which was water soluble.", "Exchanging ethanol for water gave a water-based polymer solution having similar properties to the ethanol-based material.", "Step 2 [0045] This step was carried out as in Example 1 to provide similar results.", "EXAMPLE 3 Step 1 [0046] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g Dimethylaminopropylamine 39.51 g Jeffamine M-2005 84.70 g Triethylamine 31.30 g Ethanol 510.20 g [0047] The reactor was sealed and purged with an inert gas.", "The following heating profile was initiated: Heat to 125° C. 4 hours Hold at 125° C. 12 hours Cool to 35° C. 1 hour [0048] After the heating profile was complete, the polymer solution was discharged from the reactor.", "The resultant product was a viscous, clear yellow solution.", "This material was laid down as a film and allowed to dry.", "A non-brittle film resulted.", "Exchanging with water gave a water-based polymer solution having similar properties to the ethanol-based material.", "Step 2 [0049] This step was carried out as in Example 1 to provide similar results.", "EXAMPLE 4 Step 1 [0050] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g Dimethylaminopropylamine 39.51 g Jeffamine M-2005 84.70 g Jeffamine M-2070 33.90 g Triethylamine 31.30 g Ethanol 573.17 g [0051] The reactor was sealed and purged with an inert gas.", "The following heating profile was initiated: Heat to 125° C. 4 hours Hold at 125° C. 12 hours Cool to 35° C. 1 hour [0052] After the heating profile was complete, the polymer solution was discharged from the reactor.", "The resultant material was a viscous clear yellow solution.", "This material, when laid down as a film and allowed to dry, resulted in a flexible film.", "This same material can be exchanged with water to give a water-based polymer solution having similar properties to the ethanol-based material.", "Step 2 [0053] This step was carried out as in Example 1 to provide similar results.", "EXAMPLE 5 Step 1 [0054] The following reactants were added to a 2-liter pressure reactor: Poly(isobutylene/maleic anhydride) 119.22 g Dimethylaminopropylamine 39.51 g Jeffamine M-2005 101.70 g Jeffamine M-2070 84.70 g Triethylamine 31.30 g Ethanol 699.08 g [0055] The reactor was sealed and purged with an inert gas.", "The following heating profile was initiated: Heat to 125° C. 4 hours Hold at 125° C. 12 hours Cool to 35° C. 1 hour [0056] After the heating profile was complete, the polymer solution was discharged from the reactor.", "The resultant material was a viscous clear yellow solution.", "This material, when laid down as a film and allowed to dry, resulted in a very flexible film.", "This same material can be exchanged with water to give a water-based polymer solution having similar properties to the ethanol-based material.", "Step 2 [0057] This step was carried out as in Example 1 to provide similar results.", "[0058] The compositions herein are particularly useful in products for personal care, including, but not limited to, gels, lotions, mousses, sprays, fixatives, shampoos, conditioners, 2-1 shampoos, temporary hair dyes, semi-permanent hair dyes, permanent hair dyes, straighteners, permanent waves, relaxers, creams, putties, waxes and pomades.", "The compositions can be used alone or in combination with anionic, nonionic and cationic hair styling polymers, thickeners, film formers, surfactants, reducing agents, oxidizers and other ingredients typically found in personal care products.", "Specific examples follow: [0059] Gels: [0060] Hair and/or skin care compositions wherein the compositions comprise an aqueous or hydroalcoholic gel.", "Gels can be in the form of spray gels, fluid gels, tube gels and thick viscous tub gels.", "The compositions are preferably employed at use levels of 0.1-10% by weight in anionic, nonionic or cationic gellants, or combinations thereof, such gallants preferably being present in amounts of 0.1-5% by weight.", "[0061] Anionic gellants include, but are not limited to, Carbomer®, acrylates/C10-30 alkyl acrylate crosspolymer, acrylates copolymer, acrylates/beheneth-25 methacrylate copolymer, acylates/steareth-20 methacrylate copolymer, polyvinylmethyl ether/maleic anhydride PVM/MA, alkyldiene, e.g. decadiene or octadiene crosspolymer, xanthan gum, sodium polyacrylate, polyacrylamide, copolymers of sodium acrylates, and copolymers of polyacrylamide.", "[0062] Nonionic gellants include, but are not limited to, guar and their derivatives, and celluloses and their derivatives.", "Examples are hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, hydroxypropylmethyl cellulose and hydroxypropyl guar.", "[0063] Cationic thickeners include, but are not limited to, Polyquaternium 32 (and) mineral oil, and Polyquaternium 37 (and) mineral oil (and) PPG-1 Trideceth-6.", "[0064] Hair and skin care gel formulations with the compositions herein using crosslinked homopolymers of acrylic acid, e.g., Carbomer® and/or acrylates/C10-30 alkyl acrylate crosspolymer as the gellant result in synergistic performance in moisture resistance.", "In particular, hair styling gels with the above listed combinations show synergistic high humidity resistance on hair.", "[0065] The complexation of the compositions with Carbomer® and/or acrylates/C10-30 alkyl acrylate crosspolymer results in clear films upon draw down.", "The resultant viscosity, yield value and suspension capabilities are unaffected or increased by the addition of such compositions into the gellant.", "FORMULATION EXAMPLES (% by wt) [0066] Hair Styling Gel Formulation 1 [0067] Water—QS to 100% [0068] Carbomer®-0.5 [0069] Triethanolamine (99%)—0.5 [0070] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0071] Maleimide/maleic acid copolymer (30%)—6.66 [0072] Benzophenone-4—0.05 [0073] Disodium EDTA—0.10 [0074] Triethanolamine (99%)—adjust to pH 7 [0075] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0076] Hair Styling Gel Formulation 2 [0077] Water—QS to 100% [0078] Isoceteth-20—0.5 [0079] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0080] Maleimide/maleic acid copolymer (30%)-6.66 [0081] Aminomethyl propanol—0.25 [0082] Acrylates/beheneth-25 methacrylate copolymer (20%)—4.7 [0083] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0084] Hair Styling Cream [0085] Water—QS to 100% [0086] Sodium polyacrylate (and) hydrogenated polydecene (and) trideceth-6—2.0 [0087] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer (30%)-6.7 [0088] Glycerin—2.0 [0089] Cetyl PEG/PPG-15/15 butyl ether dimethicone—1.0 [0090] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0091] Mousses: [0092] The compositions are incorporated into aerosol and non-aerosol hair and skin mousse formulations, as well as spray mousses which utilize an aerosol valve with a dip tube and a mechanical break-up actuator to deliver an atomized spray foam.", "They are also compatible in aerosol and non-aerosol shave foam applications.", "Preferred use levels of the active polymer mixture are 0.1-10.0% by weight.", "[0093] Shampoos and Body Washes: [0094] The compositions are compatible with anionic, amphoteric, cationic and nonionic surfactants.", "The compositions are incorporated into cleansing formulations for hair and body.", "The compositions are used at polymer use levels of 0.1 to 10% by weight with anionic, amphoteric, cationic, and nonionic surfactants, or combinations thereof, such surfactants preferably being present in amounts of 0.1 to 20% by weight.", "[0095] Clear Shampoo Formulation: [0096] Water—QS to 100% [0097] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer—5.0 [0098] Cocamidopropyl betaine (34.5%)—10.00 [0099] Cocoamphodiacetate (50%)-5.00 [0100] Sodium laureth sulfate (25.6)-17.5 [0101] Ammonium lauryl sulfate (29.2%)—17.5 [0102] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.30 [0103] Citric Acid—0.25 [0104] Oil-in-Water Emulsions and Hair Conditioners: [0105] The compositions are incorporated in hair and skin oil-in-water emulsions.", "In hair conditioners, the polymer mixtures are compatible with quaternary ammonium compounds.", "The use level of surfactants/emulsifiers suitably is from 0.1 to 10% by weight.", "[0106] Conditioner Formulation: [0107] Phase A: [0108] Water—QS to 100% [0109] Citric Acid—0.25 [0110] Hydroxyethyl cellulose—0.5 [0111] Disodium EDTA—0.1 [0112] Phase B: [0113] Cetearyl Alcohol—4.0 [0114] Steareth-10—1.0 [0115] Glyceryl stearate (and) PEG-100 stearate—2.5 [0116] Dicetyldimonium chloride (68.2%)-2.0 [0117] Phase C: [0118] Isobutylene/dimethylaminopropylmaleimide/ethoxylated maleimide/maleic acid copolymer (30%)—6.6 [0119] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl butylcarbamate—0.5 [0120] Wheat amino acid—0.5 [0121] Process: [0122] Heat Phases A and B separately to 75° C. Add Phase B to Phase A with agitation.", "Mix until uniform and cool to 45° C. Continue mixing and add ingredients in Phase C one at a time with mixing until homogenous.", "[0123] Oxidative Hair Dyes: [0124] The polymers are incorporated into oxidative hair dye formulations including semi-permanent and permanent hair dye products, suitably at use levels of 0.1-10% by weight.", "[0125] Formulation: [0126] Water—QS to 100% [0127] Oleic acid—5 [0128] C11-15 pareth-9—3 [0129] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0130] maleimide/maleic acid copolymer (30%)—3.0 [0131] Ammonium hydroxide—2 [0132] Steareth-21—2 [0133] Propylene glycol— 2 [0134] Cetyl alcohol— 2 [0135] PEG150/Stearyl/SMDI copolymer—3 [0136] Stearyl alcohol—1 [0137] Sodium sulfite—1 [0138] Iron oxides—0.5 [0139] Mica—0.2 [0140] 1-Naphitol—0.2 [0141] p-Phenylenediamine—0.2 [0142] Titanium dioxide—0.1 [0143] Relaxers and Permanent Waves: [0144] The compositions are used as relaxer and permanent wave formulations, suitably in amounts of 0.1%-10% by weight.", "They may be combined with hair reducing agents, including, but not limited to, ammonium thioglycolate, guanidine hydroxide, sodium bisulfite and the like.", "[0145] Formulation: [0146] Crème Hair Relaxer Base: To be mixed with guanidine carbonate [0147] Activator Solution [0148] Water—QS to 100% [0149] Petrolatum—10 [0150] Paraffin Wax—8 [0151] Mineral oil—6 [0152] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0153] maleimide/maleic acid copolymer (30%)—5.0 [0154] Cetearyl alcohol—3 [0155] Calcium hydroxide—3 [0156] Polysorbate 80—2 [0157] Laneth-15—2 [0158] PEG-75 lanolin oil—1 [0159] Cocamphodipropionate—1 [0160] Hair Sprays: [0161] The compositions are formulated as hair sprays, both non-aerosol and aerosol, suitably at use levels of 0.1-10% by weight.", "Aerosol hair sprays can include up to 60% hydrocarbon, 70% dimethyl ether, 50% hydrofluorocarbon 152a, or combinations thereof.", "Hair spray formulations include, but are not limited to, alcohol-free pump hair sprays, 55%-95% VOC pump and aerosol hair sprays.", "[0162] Formulation: [0163] Clear Alcohol Free Pump Hair Spray [0164] Water—QS to 100% [0165] Sodium lauryl sulfate (25%)—0.25 [0166] Isobutylene/dimethylaminopropylmaleimide/ethoxylated [0167] maleimide/maleic acid copolymer (30%)—13.33 [0168] Propylene glycol (and) diazolidinyl urea (and) iodopropynyl [0169] butylcarbamate—0.5 [0170] Pump—Calmar Marks VI WL-31 [0171] Personal Care Applications: [0172] The compositions are blended with anionic, nonionic and cationic hair styling polymers, thickeners, and film formers;", "and with anionic, nonionic and cationic surfactants.", "Clarity in water is increased with low levels of charged surfactants (0.1-2% by weight).", "[0173] The compositions also are formulated into bodifying leave-on and rinse-off hair preparations.", "They also can be formulated into flexible hold styling products which provide smooth, continuous films on hair that have strength and will bend under both high and low stress.", "[0174] Skin Care Applications: [0175] The compositions are used as a film former (a) for the enhancement of antiperspirants to either increase overall wetness protection or to effect a reduction in the amount of conventional actives therein while holding equivalent efficacy;", "(b) to increase the substantivity of a deodorant active for better and longer acting deodorancy;", "(c) in an anti-bacterial liquid hand soap to increase efficacy and for longer lasting claim;", "(d) for holding products on skin;", "(e) to increase contact time of a therapeutic skin product containing an active, including, but not limited to, Betulin, Vitamins E, A and C, ceramides, allantoin, lycopenes, bisabolol, retinol, and the like, and (f) to aid in the removal of sebum, and/or villous hair.", "[0176] The compositions also are used in make-up products, e.g. foundation, mascara, bronzers, eyeliners, to effect film formation, wear resistance and pigment dispersion.", "They are also used in mascaras for curl retention.", "[0177] While the invention has been described with particular reference to certain embodiments thereof, it will be understood that changes and modifications may be made which are within the skill of the art.", "Accordingly, it is intended to be bound only by the following claims, in which:" ]
FIELD OF THE INVENTION The present invention relates to a panel, and particularly relates to a solar collector panel which can also be utilized to display information and/or images. BACKGROUND OF THE INVENTION There is an increasing awareness of the need to have access to safe, accessible, inexpensive and reliable forms of energy which do not produce greenhouse gases or toxic or harmful emissions, and which are either renewable, or which are widely available and in a virtually limitless supply. To date, efforts have been made to harness, for example, wind and solar energies, but widespread adoption of these technologies has not been achieved, due in part to the expense of the combination of designing, manufacturing, installing and maintaining these technologies. Consequently, there is a need for a simple, safe, inexpensive and reliable device and method for harvesting the energy which is abundantly available in the form of solar energy. Additionally, to reduce the costs and risks generally associated with energy distribution, handling and movement, it is desirable to collect energy which is proximate to the location where the energy may be utilized, thereby reducing the costs associated with energy distribution, handling and movement. Finally, as solar panels may be utilized in places where it may be desirable or beneficial to provide from one or more solar panels, information and/or images, it is beneficial to provide this additional capability. SUMMARY OF THE INVENTION The object of the present invention is to provide a solar panel which collects solar light and converts the solar light into heat, which is available for heating homes, buildings, water and other heating and cooling applications, and for conversion into other forms of energy such as electricity. It is a further object of the present intention to provide a device which collects solar energy and converts the solar light into heat, and also provides a flat surface upon which information and/or images may be presented BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present intention is described below with reference to the accompanying drawings, in which: FIG. 1 is an exploded view of an embodiment of the solar panel of the present invention; FIG. 2 is a view of the frame of an embodiment of the solar panel of the present invention; FIG. 3 is an exploded cross-sectional view of a portion of one side of the frame, seals, glass plates, insulation and backing plate of one embodiment of the present invention; FIG. 4 is an assembled cross-sectional view of a portion of one side of the frame, seals, glass plates, insulation and backing plate of one embodiment of the present invention; FIG. 5 is the front view of one embodiment of the panel with an advertisement thereon; FIG. 6 is the front view of three panels connected together with a single continuous advertisement thereon; FIG. 7 is an exploded view of an embodiment of the present invention with ring shaped glass support members placed therein; FIG. 8 is a cutaway view of a corner of the frame; FIG. 9 is a cutaway view of a corner view of the frame with attachment brackets attached thereto. DESCRIPTION OF THE PREFERRED EMBODIMENT As described herein, in the preferred embodiment, the present invention provides, as shown in the exploded view of FIG. 1 , a panel 2 having an upper glass sheet 4 securely positioned within an external frame 8 , and a lower glass sheet 6 positioned within the external frame 8 and in spaced relation to the upper glass sheet 4 . In the preferred embodiment, the surface of the lower glass sheet 6 is coated with a material 7 shown in FIGS. 3 and 4 , which, when contacted by solar light, converts the solar light, or a substantial part thereof, into heat, some of which heat is transferred to the lower glass sheet. In the preferred embodiment, black or dark colored paint is utilized, it being understood that many different materials or coatings are readily available and known to persons skilled in the art, to convert the solar light, or substantial part thereof, into heat and to transfer some of which heat to the lower glass sheet 6 . Referring to FIGS. 3 and 4 , in the preferred embodiment, seals 10 and 12 are provided around the entire outer edge of each of the upper glass sheet and lower glass sheet respectively which are adapted to fit securely in grooves 26 on the inside surface of the frame 8 and to provide an airtight seal between the glass sheets and the frame 8 thereby providing an airtight closed volume 14 between the upper glass sheet 4 and the lower glass sheet 8 and enclosed by the frame, the volume 14 between the upper glass sheet 4 and the lower glass sheet 8 subsequently being filled, in a manner known to a person skilled in the art, with argon gas (not shown) to reduce the transfer of heat energy from the surface of the lower glass sheet to the upper glass sheet, and to reduce the overall heat loss through the upper glass sheet. In an alternative embodiment, glass support members 22 are positioned between the upper glass sheet 4 and the lower glass sheet 8 , and a partial vacuum is provided in volume 14 (the air being partially exhausted in a manner known to a person skilled in the art, by way of, for example, a sealable passageway (not shown) between volume 14 and the atmosphere, through which sealable passageway air may be partially exhausted from the volume 14 , which passageway is thereafter sealed to prevent air from thereafter traveling into the volume 14 from the atmosphere), thereby reducing the transfer of heat from the lower glass sheet to the upper glass sheet. The glass support members 22 maintain a spaced relationship between the upper glass sheet 4 and the lower glass sheet 8 , and reduce the flexing of the glass sheets (and therefore reduce the likelihood of the breakage of the glass sheets when volume 14 is subject to partial or substantial vacuum). The glass support members 22 in the preferred embodiment are made of a relatively low-heat transfer, high melting point material such as thick glass fiber matting or asbestos fiber matting, or high heat synthetic foam rubber, and by way of example, can take the form of small discs or rings 22 such as shown in FIG. 7 , or other shapes, which will support the glass sheets, minimize or reduce the flexing of the glass sheets and maintain a spaced relationship between the glass sheets. In one embodiment, tempered glass or glass of increased thickness and strength may be utilized to reduce the risk of breakage of the glass when volume 14 is placed under partial or substantial vacuum. In one embodiment, during assembly, the glass support members 22 may, for example, be individually positioned and securely affixed to the lower surface of the upper glass sheet 4 , so that when the upper glass sheet is positioned within the external frame 8 , the glass support members 22 are in contact with or proximate to the upper surface of the lower glass sheet 8 . In the preferred embodiment, a chamber 40 is provided between a backing plate 18 (which backing plate has a seal 24 around the entire outer edge thereof which is adapted to fit securely in a groove 28 on the inside surface of the frame 8 and to provide an airtight seal between the backing plate and the frame 8 , the backing plate having insulation 20 positioned thereon to reduce the heat loss through the backing plate) and the lower glass sheet 6 into which chamber 40 air is blown through one or more air intake pipes 16 , which air will come into contact with the heated lower glass sheet 6 , transferring heat from the lower glass sheet 6 to the air, which heated air is thereafter exhausted from the chamber 40 through one or more exhaust pipes (not shown, but in the preferred embodiment, of a generally similar design to the air intake pipes and of a size sufficient to easily exhaust air from the panel as required or desired). The heated air exhausted from the chamber 40 may thereafter be used to heat a room, building or other space, water or another liquid, or in a heat engine or Stirling cycle engine (either of which may be used to drive, for example, a generator for electricity or a compressor), or to create refrigerated air (by way of, for example, an ammonia gas based refrigeration system modified to use the heat from the exhaust pipe of the panel of the present invention rather than from the burning of propane gas or other fuel). In the preferred embodiment, the frame 8 is made of extruded aluminum, it being understood that a worker skilled in the art may choose alternative available materials and cross-sections for the frame. The frame may be manufactured from, for example, four lengths of extruded aluminum having a cross-section substantially as shown in FIG. 8 , preferably the ends of each of the lengths being cut at a 45 degree angle 32 , the pieces being connectable, for example, by removable brackets 34 shown in FIGS. 1 , 2 and 9 which may be screwed to, or otherwise securely fastened to the frame, it being understood that a worker skilled in the art may choose alternative techniques for securely connecting the lengths of extruded aluminum together to create the frame 8 . The frame, and the panel may be mounted outdoors to the ground, or to a building, or to a structure, and may in one embodiment be either permanently positioned (in the northern hemisphere, preferably pointed in a generally southerly direction or in a direction that has access to direct sunlight for at least a portion of the day, and in the southern hemisphere, preferably pointed in a generally northerly direction or in a direction that has access to direct sunlight for at least a portion of the day), or may be mounted on a support (not shown) which allows the frame and panel to pivot about a substantially horizontal axis, or substantially vertical axis, or both, to modify the panel's angle relative to the sun and to thereby increase, or decrease the panels' ability to capture and convert solar light into usable heat. In the preferred embodiment, the upper glass sheet is made of flat glass of thickness between 5 mm and 10 mm it being understood that a wide range of glass sizes may be utilized and where required for additional strength, tempered glass may by utilized. It is understood that a clear plastic, plexiglass, rigid transparent film or other membrane could be substituted for the upper glass sheet. Similarly, in the preferred embodiment, the lower glass sheet is made of flat glass of thickness between 5 mm and 10 mm it being understood that a wide range of glass sizes may be utilized and where required for additional strength, tempered glass may by utilized. It is understood that a sheet of metal such as steel or aluminum or other strong material having high heat transfer properties could be substituted for the lower glass sheet. As illustrated in FIG. 5 , in one embodiment, the image/information 36 “Your Name Here” may be painted onto or affixed to the top surface of the lower glass sheet. In this embodiment, a dark, preferably black, near black or dark blue background color is painted onto or affixed to a significant background portion of the top surface of the lower glass sheet, the other portion of the top surface of the lower glass sheet being painted or otherwise affixed with the image/information to be displayed (in FIG. 5 , “Your Name Here”). In this embodiment, where appropriate, any glass support members are appropriately colored to correspond with that of the image/information being displayed, that is, the glass support members being of the background color unless they are positioned in a place where image/information would otherwise be presented, in which case they are colored appropriately. It is understood that in place of the image/information “Your Name Here”, any other information or image may be substituted therefor. It is understood that rather than painting or otherwise affixing the image/information on the top surface of the bottom glass sheet, this image/information may be painted or otherwise affixed to the bottom side of the upper glass sheet, or to the top side of the upper glass sheet, in which latter case, attention must be given to the exposure of the paint or other material to the rain, snow, hail and to the elements generally. In another embodiment, a thin transparent or near-transparent film or mesh upon which the image/information is painted or affixed, may be placed above the black or darkly painted surface of the lower glass sheet or upon or above the upper surface of the upper glass sheet, or may be placed upon or below the lower surface of the upper glass sheet. In this manner, the image/information is viewable against the black or other dark background color of the panel. It is understood that to the extent that the image/information to be displayed from the panel may utilize colors which reflect, block, filter, partially filter or which are generally less than optimal for the collecting of solar light and converting same into heat, it is desirable when choosing how to display an image/information, where possible and appropriate, to choose color schemes and image display techniques which to the extent possible, maintain significant overall performance of the panel. For example, it is understood that where possible, a relatively dense white (or other colored) dot (or other shaped element) pattern, with spaces between the dots, may be utilized to display the image/information which image/information would appear solid at a typical viewing distance from the panel while at the same time permitting significant exposure of sunlight onto the black or darkened surface of the lower glass sheet. It is understood that a person skilled in the art of graphic design will select an appropriate size, shape and density of the white (or other colored) dots (or other shaped elements) so that the image/information is clear and readily viewable and attractive against the background color of the panel while at the same time maximizing the amount of light which may come into contact with the black or darkened lower glass sheet surface. In the preferred embodiment, advertisements, logos or other image/information may be painted or otherwise affixed to the top surface of the lower glass sheet (or upon the black or dark colored paint which has been painted thereon), or on to the lower or upper surface on the upper glass sheet. In an alternative embodiment, a transparent film, for example, made of clear plastic, upon which an advertisement, logo or other image/information materials is provided. The advertisement, logo or other image/information may be painted or otherwise affixed to the transparent film. The transparent film may be affixed to the top surface of the lower glass sheet (or the black or dark colored paint which has been painted thereon), or on to the lower or upper surface on the upper glass sheet in manners known to persons skilled in the art, including, for example, by means of a semi-sticky adhesive which permits the transparent film to be securely affixed to the panel, while readily permitting the film to be removed from the panel when desired. In the embodiments where the film is affixed to the top surface of the lower glass (or upon the black or dark colored paint which has been painted thereon), or on to the lower surface of the upper glass sheet, where glass support members are utilized, these members are adapted to support and separate the glass plates and the film affixed thereto. The panel may display, for example, governmental, public service, corporate, business or other advertising or information. Alternatively, where desired, the panel may display an attractive image. For example, a panel which may be installed next to a public swimming pool may display an attractive stylized wave pattern against a dark blue background, or a panel which is installed on an exterior house wall may display a pleasant stylized image of distant stars against a black background. The panel may be mounted, for example at an outdoor stadium, on the top of, or on the external wall of, or adjacent to a commercial or retail building where the benefits of both the advertisements displayed from the panel and the heated air from the panel may be utilized (it being understood that the heated air may be ducted into the HVAC system of the building to supplement the heating requirements of the building, or the heated air may be utilized to create refrigerated air (by way of, for example, an ammonia gas based refrigeration system modified to use the heat from the exhaust pipe of the panel of the present invention rather than from the burning of propane gas or other fuel) or electricity (by way of a generator coupled to a Stirling engine or other heat engine) to the building or for external use. The revenue derived from the advertising and/or display of information from the panel may offset some of the costs of the acquisition, installation and maintenance of the panel. As illustrated in FIG. 6 , multiple panels 2 may be arranged to provide an array of panels 38 in close proximity to or abutting one another, the frame member being colored appropriately to provide a clear, unobstructed, uncluttered and attractive view of the image/information being displayed from the combined panel array (the broken white lines 40 appears in FIG. 6 solely to represent the location where panels abut one another, the broken white lines not appearing in the device when being utilized). In one embodiment of the present invention, a method of conducting business is established, in which one manufactures panels of the type described herein which are available for sale, lease or otherwise the subject of a commercial transaction with a customer. In another embodiment, the business provides customers with temporary or permanent advertising or information display space on a panel of the type described herein, and in the case of the provision of temporary advertising or information display space, the space on the panel is made available for a period of time, which when elapsed, is available for other customers to be utilized in the same manner. In another embodiment, the business methodology provides making advertising or information space available to third parties, and installing advertising, logos or other image/information materials on the panel, on either a temporary or permanent basis. The present invention has been described herein with regard to preferred embodiments. However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein.
A solar collector panel which can also be utilized to display information and/or images and/or messages and having an external frame, with a transparent upper panel securely positioned within the frame. A lower panel is positioned within the frame and spaced in relation to the upper panel so as to provide a closed chamber between the upper panel and the lower panel, an upper surface of the lower panel having applied thereon heat conversion means for converting solar radiation to heat energy, the heat conversion means providing thereon information, an image or message which is visible above the upper surface of the upper panel. A back panel is positioned within the frame, so as to define a closed volume of air space between the lower panel and the back panel through which air may flow. Intake and exhaust pipes introduce air into the frame, and transfer heated air from the frame.
Condense the core contents of the given document.
[ "FIELD OF THE INVENTION The present invention relates to a panel, and particularly relates to a solar collector panel which can also be utilized to display information and/or images.", "BACKGROUND OF THE INVENTION There is an increasing awareness of the need to have access to safe, accessible, inexpensive and reliable forms of energy which do not produce greenhouse gases or toxic or harmful emissions, and which are either renewable, or which are widely available and in a virtually limitless supply.", "To date, efforts have been made to harness, for example, wind and solar energies, but widespread adoption of these technologies has not been achieved, due in part to the expense of the combination of designing, manufacturing, installing and maintaining these technologies.", "Consequently, there is a need for a simple, safe, inexpensive and reliable device and method for harvesting the energy which is abundantly available in the form of solar energy.", "Additionally, to reduce the costs and risks generally associated with energy distribution, handling and movement, it is desirable to collect energy which is proximate to the location where the energy may be utilized, thereby reducing the costs associated with energy distribution, handling and movement.", "Finally, as solar panels may be utilized in places where it may be desirable or beneficial to provide from one or more solar panels, information and/or images, it is beneficial to provide this additional capability.", "SUMMARY OF THE INVENTION The object of the present invention is to provide a solar panel which collects solar light and converts the solar light into heat, which is available for heating homes, buildings, water and other heating and cooling applications, and for conversion into other forms of energy such as electricity.", "It is a further object of the present intention to provide a device which collects solar energy and converts the solar light into heat, and also provides a flat surface upon which information and/or images may be presented BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of the present intention is described below with reference to the accompanying drawings, in which: FIG. 1 is an exploded view of an embodiment of the solar panel of the present invention;", "FIG. 2 is a view of the frame of an embodiment of the solar panel of the present invention;", "FIG. 3 is an exploded cross-sectional view of a portion of one side of the frame, seals, glass plates, insulation and backing plate of one embodiment of the present invention;", "FIG. 4 is an assembled cross-sectional view of a portion of one side of the frame, seals, glass plates, insulation and backing plate of one embodiment of the present invention;", "FIG. 5 is the front view of one embodiment of the panel with an advertisement thereon;", "FIG. 6 is the front view of three panels connected together with a single continuous advertisement thereon;", "FIG. 7 is an exploded view of an embodiment of the present invention with ring shaped glass support members placed therein;", "FIG. 8 is a cutaway view of a corner of the frame;", "FIG. 9 is a cutaway view of a corner view of the frame with attachment brackets attached thereto.", "DESCRIPTION OF THE PREFERRED EMBODIMENT As described herein, in the preferred embodiment, the present invention provides, as shown in the exploded view of FIG. 1 , a panel 2 having an upper glass sheet 4 securely positioned within an external frame 8 , and a lower glass sheet 6 positioned within the external frame 8 and in spaced relation to the upper glass sheet 4 .", "In the preferred embodiment, the surface of the lower glass sheet 6 is coated with a material 7 shown in FIGS. 3 and 4 , which, when contacted by solar light, converts the solar light, or a substantial part thereof, into heat, some of which heat is transferred to the lower glass sheet.", "In the preferred embodiment, black or dark colored paint is utilized, it being understood that many different materials or coatings are readily available and known to persons skilled in the art, to convert the solar light, or substantial part thereof, into heat and to transfer some of which heat to the lower glass sheet 6 .", "Referring to FIGS. 3 and 4 , in the preferred embodiment, seals 10 and 12 are provided around the entire outer edge of each of the upper glass sheet and lower glass sheet respectively which are adapted to fit securely in grooves 26 on the inside surface of the frame 8 and to provide an airtight seal between the glass sheets and the frame 8 thereby providing an airtight closed volume 14 between the upper glass sheet 4 and the lower glass sheet 8 and enclosed by the frame, the volume 14 between the upper glass sheet 4 and the lower glass sheet 8 subsequently being filled, in a manner known to a person skilled in the art, with argon gas (not shown) to reduce the transfer of heat energy from the surface of the lower glass sheet to the upper glass sheet, and to reduce the overall heat loss through the upper glass sheet.", "In an alternative embodiment, glass support members 22 are positioned between the upper glass sheet 4 and the lower glass sheet 8 , and a partial vacuum is provided in volume 14 (the air being partially exhausted in a manner known to a person skilled in the art, by way of, for example, a sealable passageway (not shown) between volume 14 and the atmosphere, through which sealable passageway air may be partially exhausted from the volume 14 , which passageway is thereafter sealed to prevent air from thereafter traveling into the volume 14 from the atmosphere), thereby reducing the transfer of heat from the lower glass sheet to the upper glass sheet.", "The glass support members 22 maintain a spaced relationship between the upper glass sheet 4 and the lower glass sheet 8 , and reduce the flexing of the glass sheets (and therefore reduce the likelihood of the breakage of the glass sheets when volume 14 is subject to partial or substantial vacuum).", "The glass support members 22 in the preferred embodiment are made of a relatively low-heat transfer, high melting point material such as thick glass fiber matting or asbestos fiber matting, or high heat synthetic foam rubber, and by way of example, can take the form of small discs or rings 22 such as shown in FIG. 7 , or other shapes, which will support the glass sheets, minimize or reduce the flexing of the glass sheets and maintain a spaced relationship between the glass sheets.", "In one embodiment, tempered glass or glass of increased thickness and strength may be utilized to reduce the risk of breakage of the glass when volume 14 is placed under partial or substantial vacuum.", "In one embodiment, during assembly, the glass support members 22 may, for example, be individually positioned and securely affixed to the lower surface of the upper glass sheet 4 , so that when the upper glass sheet is positioned within the external frame 8 , the glass support members 22 are in contact with or proximate to the upper surface of the lower glass sheet 8 .", "In the preferred embodiment, a chamber 40 is provided between a backing plate 18 (which backing plate has a seal 24 around the entire outer edge thereof which is adapted to fit securely in a groove 28 on the inside surface of the frame 8 and to provide an airtight seal between the backing plate and the frame 8 , the backing plate having insulation 20 positioned thereon to reduce the heat loss through the backing plate) and the lower glass sheet 6 into which chamber 40 air is blown through one or more air intake pipes 16 , which air will come into contact with the heated lower glass sheet 6 , transferring heat from the lower glass sheet 6 to the air, which heated air is thereafter exhausted from the chamber 40 through one or more exhaust pipes (not shown, but in the preferred embodiment, of a generally similar design to the air intake pipes and of a size sufficient to easily exhaust air from the panel as required or desired).", "The heated air exhausted from the chamber 40 may thereafter be used to heat a room, building or other space, water or another liquid, or in a heat engine or Stirling cycle engine (either of which may be used to drive, for example, a generator for electricity or a compressor), or to create refrigerated air (by way of, for example, an ammonia gas based refrigeration system modified to use the heat from the exhaust pipe of the panel of the present invention rather than from the burning of propane gas or other fuel).", "In the preferred embodiment, the frame 8 is made of extruded aluminum, it being understood that a worker skilled in the art may choose alternative available materials and cross-sections for the frame.", "The frame may be manufactured from, for example, four lengths of extruded aluminum having a cross-section substantially as shown in FIG. 8 , preferably the ends of each of the lengths being cut at a 45 degree angle 32 , the pieces being connectable, for example, by removable brackets 34 shown in FIGS. 1 , 2 and 9 which may be screwed to, or otherwise securely fastened to the frame, it being understood that a worker skilled in the art may choose alternative techniques for securely connecting the lengths of extruded aluminum together to create the frame 8 .", "The frame, and the panel may be mounted outdoors to the ground, or to a building, or to a structure, and may in one embodiment be either permanently positioned (in the northern hemisphere, preferably pointed in a generally southerly direction or in a direction that has access to direct sunlight for at least a portion of the day, and in the southern hemisphere, preferably pointed in a generally northerly direction or in a direction that has access to direct sunlight for at least a portion of the day), or may be mounted on a support (not shown) which allows the frame and panel to pivot about a substantially horizontal axis, or substantially vertical axis, or both, to modify the panel's angle relative to the sun and to thereby increase, or decrease the panels'", "ability to capture and convert solar light into usable heat.", "In the preferred embodiment, the upper glass sheet is made of flat glass of thickness between 5 mm and 10 mm it being understood that a wide range of glass sizes may be utilized and where required for additional strength, tempered glass may by utilized.", "It is understood that a clear plastic, plexiglass, rigid transparent film or other membrane could be substituted for the upper glass sheet.", "Similarly, in the preferred embodiment, the lower glass sheet is made of flat glass of thickness between 5 mm and 10 mm it being understood that a wide range of glass sizes may be utilized and where required for additional strength, tempered glass may by utilized.", "It is understood that a sheet of metal such as steel or aluminum or other strong material having high heat transfer properties could be substituted for the lower glass sheet.", "As illustrated in FIG. 5 , in one embodiment, the image/information 36 “Your Name Here”", "may be painted onto or affixed to the top surface of the lower glass sheet.", "In this embodiment, a dark, preferably black, near black or dark blue background color is painted onto or affixed to a significant background portion of the top surface of the lower glass sheet, the other portion of the top surface of the lower glass sheet being painted or otherwise affixed with the image/information to be displayed (in FIG. 5 , “Your Name Here”).", "In this embodiment, where appropriate, any glass support members are appropriately colored to correspond with that of the image/information being displayed, that is, the glass support members being of the background color unless they are positioned in a place where image/information would otherwise be presented, in which case they are colored appropriately.", "It is understood that in place of the image/information “Your Name Here”, any other information or image may be substituted therefor.", "It is understood that rather than painting or otherwise affixing the image/information on the top surface of the bottom glass sheet, this image/information may be painted or otherwise affixed to the bottom side of the upper glass sheet, or to the top side of the upper glass sheet, in which latter case, attention must be given to the exposure of the paint or other material to the rain, snow, hail and to the elements generally.", "In another embodiment, a thin transparent or near-transparent film or mesh upon which the image/information is painted or affixed, may be placed above the black or darkly painted surface of the lower glass sheet or upon or above the upper surface of the upper glass sheet, or may be placed upon or below the lower surface of the upper glass sheet.", "In this manner, the image/information is viewable against the black or other dark background color of the panel.", "It is understood that to the extent that the image/information to be displayed from the panel may utilize colors which reflect, block, filter, partially filter or which are generally less than optimal for the collecting of solar light and converting same into heat, it is desirable when choosing how to display an image/information, where possible and appropriate, to choose color schemes and image display techniques which to the extent possible, maintain significant overall performance of the panel.", "For example, it is understood that where possible, a relatively dense white (or other colored) dot (or other shaped element) pattern, with spaces between the dots, may be utilized to display the image/information which image/information would appear solid at a typical viewing distance from the panel while at the same time permitting significant exposure of sunlight onto the black or darkened surface of the lower glass sheet.", "It is understood that a person skilled in the art of graphic design will select an appropriate size, shape and density of the white (or other colored) dots (or other shaped elements) so that the image/information is clear and readily viewable and attractive against the background color of the panel while at the same time maximizing the amount of light which may come into contact with the black or darkened lower glass sheet surface.", "In the preferred embodiment, advertisements, logos or other image/information may be painted or otherwise affixed to the top surface of the lower glass sheet (or upon the black or dark colored paint which has been painted thereon), or on to the lower or upper surface on the upper glass sheet.", "In an alternative embodiment, a transparent film, for example, made of clear plastic, upon which an advertisement, logo or other image/information materials is provided.", "The advertisement, logo or other image/information may be painted or otherwise affixed to the transparent film.", "The transparent film may be affixed to the top surface of the lower glass sheet (or the black or dark colored paint which has been painted thereon), or on to the lower or upper surface on the upper glass sheet in manners known to persons skilled in the art, including, for example, by means of a semi-sticky adhesive which permits the transparent film to be securely affixed to the panel, while readily permitting the film to be removed from the panel when desired.", "In the embodiments where the film is affixed to the top surface of the lower glass (or upon the black or dark colored paint which has been painted thereon), or on to the lower surface of the upper glass sheet, where glass support members are utilized, these members are adapted to support and separate the glass plates and the film affixed thereto.", "The panel may display, for example, governmental, public service, corporate, business or other advertising or information.", "Alternatively, where desired, the panel may display an attractive image.", "For example, a panel which may be installed next to a public swimming pool may display an attractive stylized wave pattern against a dark blue background, or a panel which is installed on an exterior house wall may display a pleasant stylized image of distant stars against a black background.", "The panel may be mounted, for example at an outdoor stadium, on the top of, or on the external wall of, or adjacent to a commercial or retail building where the benefits of both the advertisements displayed from the panel and the heated air from the panel may be utilized (it being understood that the heated air may be ducted into the HVAC system of the building to supplement the heating requirements of the building, or the heated air may be utilized to create refrigerated air (by way of, for example, an ammonia gas based refrigeration system modified to use the heat from the exhaust pipe of the panel of the present invention rather than from the burning of propane gas or other fuel) or electricity (by way of a generator coupled to a Stirling engine or other heat engine) to the building or for external use.", "The revenue derived from the advertising and/or display of information from the panel may offset some of the costs of the acquisition, installation and maintenance of the panel.", "As illustrated in FIG. 6 , multiple panels 2 may be arranged to provide an array of panels 38 in close proximity to or abutting one another, the frame member being colored appropriately to provide a clear, unobstructed, uncluttered and attractive view of the image/information being displayed from the combined panel array (the broken white lines 40 appears in FIG. 6 solely to represent the location where panels abut one another, the broken white lines not appearing in the device when being utilized).", "In one embodiment of the present invention, a method of conducting business is established, in which one manufactures panels of the type described herein which are available for sale, lease or otherwise the subject of a commercial transaction with a customer.", "In another embodiment, the business provides customers with temporary or permanent advertising or information display space on a panel of the type described herein, and in the case of the provision of temporary advertising or information display space, the space on the panel is made available for a period of time, which when elapsed, is available for other customers to be utilized in the same manner.", "In another embodiment, the business methodology provides making advertising or information space available to third parties, and installing advertising, logos or other image/information materials on the panel, on either a temporary or permanent basis.", "The present invention has been described herein with regard to preferred embodiments.", "However, it will be obvious to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as described herein." ]
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit and priority of German Patent Application No. 10 2007 062 675.6, filed Dec. 24, 2007. The entire disclosure of the above application is incorporated herein by reference. FIELD The present disclosure relates to a method for the control of an assembly by a control unit, in particular in a motor vehicle. The assembly includes at least one component, at least one actuator associated with the component, and an additional control unit having a first non-volatile memory section that is connected to the control unit, with the control unit including a second non-volatile memory section. BACKGROUND This section provides background information related to the present disclosure which is not necessarily prior art. An assembly of this kind may be a transfer case, for example, that allows a direct distribution of a driving torque between two wheels of an axle of the motor vehicle and/or—with an all-wheel drive vehicle—a direct distribution of the driving torque between a front axle and a rear axle of the motor vehicle. Such assemblies have to be controlled with high accuracy to be able to carry out the distribution of the driving torque with the required precision. However, hardly avoidable tolerances occur in their manufacture that result in deviations in the response behavior of the assemblies. These deviations are determined individually for the purpose of a calibration, with a respective tolerance class being associated with the assemblies in accordance with a predetermined classification scheme. The respectively determined tolerance class of a specific assembly may be taken into account by the associated control unit of the vehicle to control the assembly with the desired precision. There is a problem in connection with a classification of controllable assemblies—whether in automotive engineering or in other fields—in that the respective assembly and the control unit associated therewith are sometimes installed independently of one another. A teach-in process therefore usually takes place after the installation of the assembly and the control unit in which the respective then current classification of the assembly used is communicated to the control unit and is stored in it. If a replacement or repair of the assembly and/or of the control unit takes place later, for example in case of service, the teach-in process has to be carried out again so that the correct control of the assembly by the control unit is in turn ensured. It has already been proposed to encode the classification of an assembly with the help of an additional coding plug. DE 103 33 651 A1, for example, describes a coding plug that can be connected directly or indirectly to a control unit and which has a fixed electric circuit. A defined electrical state may be generated by the fixed circuit in the control unit and the state is detected and compared with stored data. The electrical state is then associated with a tolerance class of the assembly that may in turn be used for the adaptation of maps/characteristics for the control of the assembly. It is, however, disadvantageous with this solution that an additional failure risk of the controllable assembly arises due to the coding plug made as an additional component. Furthermore, the reading out, decoding and comparing of the classification information stored in the circuit of the coding plug may only be realized in a relatively complex and/or expensive manner. In addition, the coding plug likewise has to be replaced on a change of the tolerance class of the assembly. Ultimately, it thus cannot be precluded that a coding plug is connected to the controllable assembly that contains an incorrect classification so that the classification read out of the coding plug by the control unit does not reflect the correct tolerance class of the assembly. The control of the assembly is thereby even made worse under certain circumstances—in comparison with a control solution without any consideration of the tolerance class. SUMMARY This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. It is an object of the present disclosure to provide a method for the control of an assembly that ensures in a simple and reliable manner that the assembly is controlled by the control unit while taking account of the respective then current classification information. It is furthermore an object of the present disclosure to provide an assembly group that includes a controllable assembly and a control unit that may be operated in a corresponding manner reliably and while taking account of the respective then current classification information. As already initially mentioned, the present disclosure relates to a method for the control of an assembly by a control unit, wherein the assembly includes at least one component, at least one actuator associated with the component, and an additional control unit having a first non-volatile memory section and which is connected to the control unit, with the control unit including a second non-volatile memory section. In accordance with the disclosure, classification information associated with the assembly and stored in the first non-volatile memory section is read out and transmitted to the control unit. The transmitted classification information is stored in the second non-volatile memory section. Subsequently, the classification information stored in the second non-volatile memory section is read out and transmitted to the additional control unit. In other words, a bidirectional exchange of classification information takes place between the additional control unit and the control unit, with it not being significant which of the two units actively initiates or carries out the transmission of the classification information. It is, for example, possible that a respective one of the control units is responsible for one of the transmission directions or that one of the control units controls both transmission directions. It is, however, important that the classification information stored in the first non-volatile memory section is stored after the reading out and the transmission to the control unit in the second non-volatile memory section there. This classification information is read out again and is transmitted back to the additional control unit. Generally, the method may also start with the reading out of the memory content of the second non-volatile memory section and with the transmission of the classification information to the additional control unit. The data exchange between the control unit and the additional control unit ensures that classification information associated with the actually installed assembly is always exchanged. For example, on a change of the classification information stored in the first non-volatile memory section, the classification information is transmitted to the control unit by the method in accordance with the disclosure and is stored there in its second non-volatile memory section. The classification information transmitted back to the additional control unit may be used, for example, for comparison purposes, test purposes, or other purposes. After the transmission of the classification information in the control unit, the new classification is in every case present there and may be used, for example, for optimization of the assembly control. The classification information transmitted to the additional control unit is preferably stored in the first non-volatile memory section if the first non-volatile memory section does not contain any classification information. This may be the case, for example, if the additional control unit was replaced or if the memory content of the first non-volatile memory section was deleted. The additional control unit then receives the classification information stored in the second non-volatile memory section of the control unit, whereby the data loop is again completed. In a further embodiment of the present disclosure, the classification information transmitted to the additional control unit is not stored in the first non-volatile memory section if the first non-volatile memory section already contains classification information. This, for example, prevents the overwriting of previously stored and assembly-specific classification information. The non-stored classification information may be ignored or may be further processed for comparison purposes. In a preferred embodiment of the present invention, the classification information is used by the control unit for the adaptation of at least one map or of at least one characteristic to improve the control of the assembly. The relationship stored in the control unit between a control signal and the thereby generated response of the assembly may, for example, be modified in dependence on the classification information to obtain a corrected relationship that allows a more precise control of the assembly. Provision may furthermore be made that the classification information is composed of at least two pieces of partial information, with one of the pieces of partial information being associated with the component as a component classification and the other piece of partial information being associated with the actuator as an actuator classification. This allows an even more individual taking into account of the individual components of the assembly on its control. Changes in the tolerance class of the component and/or of the actuator—for instance, on a repair or a replacement of the component and/or of the actuator—may thereby, for example, be taken into account separately from one another. Further components of the assembly may likewise be taken into account by corresponding pieces of partial information. Generally, pieces of partial information may also be provided that do not contain any tolerance class information, such as serial numbers or the like. In accordance with a further embodiment of the method in accordance with the disclosure, the pieces of partial information of the classification information stored in the second non-volatile memory section are overwritten by the corresponding pieces of partial information transmitted to the control unit, whereby it is prevented that different pieces of information that may differ from one another are collected in the second non-volatile memory section. The then currently valid pieces of partial information are therefore always present in the control unit due to the overwriting. It must be noted in this connection that in each case only the corresponding pieces of partial information are overwritten by new pieces of partial information, (i.e., a stored value of the then current component classification should, for example, not be overwritten by a value of the actuator classification, but rather the component classification value stored in the second non-volatile memory section should be overwritten by the component classification value transmitted by the additional control unit). A comparison of the stored component classification value with the transmitted component classification value before the storing is not necessary in this respect. A check only has to be made whether the transmitted component classification value is “empty” or is flagged as “empty”, for example by the value “0”. If the transmitted classification information contains, for example, only a first piece of partial information (i.e., a second piece of partial information is “empty” or is flagged as an “empty” piece of partial information) only the transmitted first piece of partial information is used for the overwriting of the first piece of partial information stored in the second non-volatile memory section. A second piece of partial information stored there is not overwritten or changed. It is preferred that the actuator and the additional control unit associated with it are replaced by a replacement actuator and by a replacement additional control unit associated with it in case of service, with its first non-volatile memory section only including the actuator classification. In other words, the first non-volatile memory sections does not contain any component classification if the component was not replaced in the course of the servicing. In accordance with the method in accordance with the disclosure, the valid component classification is still stored in the control unit and, after the replacement of the actuator and of the additional control unit, it is again transmitted to the latter and is stored there to complete the data loop. It is preferred if, in the case described above, the actuator classification includes information characterizing a typical actuator or information individually determined for the replacement actuator. The first variant is particularly cost-effective since it only provides for the storage of an actuator classification of a typical or “average” actuator. Costs are saved due to the waiving of an individual characterization of the replacement actuator and the storage of the corresponding actuator classification, while an at least “averagely” good control of the actuator still remains possible. The second variant in contrast allows a more precise control of the assembly; however, it is associated with an increased effort and/or cost. It is generally possible that, on a replacement of the component and/or of the actuator without a replacement of the additional control unit, the component classification and/or the actuator classification are each replaced by information that characterizes a typical component or a typical actuator or that was determined individually for the component or for the replacement actuator. The procedure of the first variant includes, for example, a resetting of the additional control unit to default values of the component classification and of the actuator classification since the obsolete classifications associated with the previously used components could result in worse control results in interaction with the new components. The second variant in contrast allows a more precise control of the assembly; however, it is associated with an increased effort and/or cost. In accordance with a further embodiment of the method in accordance with the disclosure, the pieces of partial information transmitted to the additional control unit are not stored in the first non-volatile memory section if the first non-volatile memory section already contains values for the corresponding piece of partial information. In other words, a check is made whether the parts of the first non-volatile memory section associated with the individual pieces of partial information are “empty” or are flagged as “empty”—for example by the value “0”—before a storage of the corresponding piece of partial information takes place. It should be prevented in this way that information stored in the additional control unit is overwritten. Provision may furthermore be made that the pieces of partial information transmitted to the additional control unit is stored in the first non-volatile memory section if the first non-volatile memory section does not contain any values for the corresponding pieces of partial information. In this variant of the method, in particular the total classification information is stored if only the additional control device was replaced and does not have an empty first non-volatile memory section, or a first non-volatile memory section flagged as “empty”, but the actuator and the component were not replaced. In this case, the memory content of the first non-volatile memory section is updated again by the data transmitted by the control unit. It has proved to be advantageous if the classification information associated with the assembly and/or the pieces of partial information associated with the individual components of the assembly is/are determined ex works (i.e., where the individual components are manufactured) and is/are stored in the first non-volatile memory section. The transmission of the classification information to the control unit can take place at predetermined times or after reception of a request signal. This can, for example, be done regularly or after an initialization at the start of an ignition procedure of the vehicle. Furthermore, the transmission of the classification information to the additional control unit may also take place at predetermined times or after reception of a request signal, in particular after reception of data from the additional control unit or at regular intervals. The classification information preferably includes information on the tolerance class of the component and/or of the actuator, in particular to adapt at least one map/one characteristic to control the assembly. A more complex and/or expensive embodiment, but one that allows a particularly precise control of the assembly, provides that the classification information includes a map/a characteristic of the assembly, of the component and/or of the actuator. For example, a torque characteristic is transmitted which covers the total torque range of a torque transmission clutch. As already initially mentioned, the present disclosure also relates to an assembly group that has a controllable assembly and a control unit, in particular for a motor vehicle, with the controllable assembly including at least one component, at least one actuator associated with the component and an additional control unit having a first non-volatile memory section, with the control unit including a second non-volatile memory section and with the control unit and the additional control unit being connected to one another by a data transmission path. In accordance with the disclosure, the first non-volatile memory section is made for the storage of classification information associated with the assembly, whereas the data transmission path is designed such that the classification information may be transmitted from the additional control unit to the control unit and vice versa. The control unit is made for the transmission of the classification information to the additional control unit. A two-way transmission of the classification information between the additional control unit and the control unit is thereby made possible in order, for instance, also always to have current classification information present after a case of servicing. The additional control unit preferably includes a test unit that is made to check the memory content of the first non-volatile memory section and to store the classification information, or parts thereof, transmitted to the additional control unit in the first non-volatile memory section if no classification information or if incomplete classification information is stored in the first non-volatile memory section—for instance, classification information not including all pieces of partial information. In other words, it is determined by the test unit whether the memory content of the first non-volatile memory section is “empty” or is flagged as “empty”—in part or in total. In this respect, it is not the stored value of the information which is important, but rather whether this information is present at all, with it having to be pointed out in this connection that specific values—such as “0”—can only serve as a flag to indicate that the corresponding information is not present. If no partial information or no corresponding pieces of partial information is/are present, this is stored in the first non-volatile memory section. The test unit thus ensures that always current information is stored in the additional control unit. In addition, the control unit may include a memory unit which is made to overwrite the classification information, or parts thereof, stored in the second non-volatile memory section by the classification information, or corresponding parts thereof, transmitted by the additional control unit. The information present in the control unit is updated by the overwriting. This procedure moreover saves memory space. In accordance with an embodiment of the assembly group in accordance with the information, some of the pieces of classification information may be transmitted over the data transmission path and/or may be stored in and/or read out of the first and second non-volatile memory sections independently of one another. The component is preferably a torque transmission clutch. The assembly may be a transfer case. Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. FIG. 1 is a schematic representation of a part of a motor vehicle with a controllable assembly made in accordance with the disclosure; and FIG. 2 is a schematic design of a controllable assembly made in accordance with the disclosure with a control unit connected thereto. Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION Example embodiments will now be described more fully with reference to the accompanying drawings. A powertrain 10 of a motor vehicle having a drive 12 is shown schematically in FIG. 1 . The drive 12 includes an engine 14 and a transmission 16 that is connected to a transfer case 20 via a drive shaft 18 . The transfer case 20 serves to distribute the driving torque of the engine 14 as required via output shafts 36 to a front axle 22 and/or to a rear axle 24 of the vehicle. Depending on the driving situation, the driving torque may, for example, only be transferred by the transfer case 20 to one of the axles 22 , 24 or to both axles 22 , 24 in variable proportions. The axles 22 , 24 each include a differential unit 26 that is provided for the compensation of speed differences between wheels 28 . To be able to influence the different driving situations of the vehicle, the vehicle has a control unit 30 that receives information on the state and on the movements of the vehicle and its environment via a plurality of sensors (not shown). This data is logged and evaluated by the control unit 30 . The evaluation of the data allows the generation of control signals that are in turn transmitted to the components of the vehicle to control the vehicle in the desired manner. For example, control lines 50 are shown in FIG. 1 which connect the control unit 30 to the engine 14 , to the transmission 16 , and to the transfer case 20 . A data bus, in particular a CAN bus, may also be provided instead of separate control lines 50 . The control signals are in particular present in a digital format. FIG. 2 is a very simplified schematic representation of the transfer case 20 and of the control unit 30 connected thereto. The transfer case 20 includes a transfer case unit 34 that allows a torque of the drive shaft 18 to be distributed selectively to the output shafts 36 that are connected to the respective differential unit 26 of the front axle 22 or of the rear axle 24 , respectively (see FIG. 1 ). The selective distribution of the torque of the drive shaft 18 depends on the state of a friction clutch 38 of the transfer case unit 34 . For example, the driving torque is only transmitted to the rear axle 24 with an open friction clutch 38 . To transmit some of the driving torque to the front axle 22 as well, the friction clutch 38 is brought into engagement at least partially. In other words, the portion of the driving torque transmitted to the front axle 22 is a function of the degree of actuation of the friction clutch 38 . The precise actuation of the clutch 38 is thus of great significance to allow a precisely defined distribution of the driving torque to the axles 22 , 24 . It must be taken into account in this connection that each friction clutch 38 has production-induced properties. This likewise applies to a clutch actuator 40 that can selectively bring the friction clutch 38 into engagement (i.e., the friction clutch 38 and the clutch actuator 40 respond to a given control signal in a characteristic manner which differs from other friction clutches 38 or clutch actuators 40 basically of the same construction). These practically unavoidable differences originate, for example, in manufacture-induced production tolerances and/or in slight variations of the properties of the material used. To ensure the desired distribution of the driving torque with the required precision, it is necessary to take the characteristics of each transfer case 20 into account individually and to adapt the control signals supplied to it accordingly. This is effected in that the individual components of the transfer case 20 are measured individually or in total at the end of production (i.e., the response of the components or of the total transfer case 20 to specific control signals is observed and a special characteristic is determined). This is in particular characterized by the torque transmission characteristics of the friction clutch 38 and the behavior of the clutch actuator 40 . The specific characteristics are associated with one of a plurality of tolerance classes. The control signals for the transfer case 20 may be adapted with reference to the specific tolerance class—for instance by adaptation of maps/characteristics—to achieve a distribution of the driving torque which is as exact as possible. The control signals of the control unit 30 are supplied to the clutch actuator 40 via an additional control unit 42 and via a control line 50 ′. The additional control unit 42 has an additional control unit memory 44 in which the tolerance class described above is stored. The control signals transmitted by the control unit 30 may be adapted in the additional control unit 42 while taking the tolerance class into account to be able to provide adapted control signals to the clutch actuator 40 . It is expedient, however, to make the additional control unit 42 as simple as possible and to carry out the correction of the control signals in the control unit 30 . For this purpose, the control unit 30 must be supplied with the corresponding tolerance class information. This is done by the additional control unit 42 reading out the tolerance class information from the additional control unit memory 44 and transmitting it to the control unit 30 . This information may be stored in a control unit memory 46 by a control unit 54 . The information stored in the control unit memory 46 is used for the adaptation of characteristics 48 that are used for the generation of control signals for the transfer case 20 . The tolerance class information stored in the control unit memory 46 is subsequently again transmitted to the additional control unit 42 via the control line 50 , whereupon the memory content of the additional control unit memory 44 is checked by a test section 52 . If the additional control unit memory 44 already has a stored value, the value transmitted by the control unit 30 is ignored. If the additional control unit memory 44 is, however, empty or is flagged as “empty”, the transmitted information is written into the additional control unit memory 44 . The process subsequently starts again with the reading out and the transmission of the information stored in the additional control unit memory 44 to the control unit 30 . An exchange of information between the additional control unit 42 and the control unit 30 thus takes place at predetermined times, at regular intervals or in response to request signals. The exchange of data is in particular of importance after an initialization at the start of an ignition procedure of the vehicle. If a tolerance class determined ex works (i.e., where the individual components are manufactured) was stored in the additional control unit memory 44 , the correct value is stored in the control unit memory 46 of the control unit 30 after a first transmission of this information. The value of the tolerance class transmitted back to the additional control unit 42 , therefore, agrees with the originally stored value. As described above, this tolerance class information is ignored since the additional control unit memory 44 already contains corresponding information. If, however, the additional control unit 42 was removed and replaced by a new additional control unit 42 , the additional control unit memory 44 is empty or is flagged as “empty”. On a take-up of communication between the new additional control unit 42 and the control unit 30 , no information is transmitted from the additional control unit 42 to the control unit 30 . However, the correct tolerance class information of the friction clutch 38 and of the clutch actuator 40 is still contained in the control unit memory 46 . This information is transmitted in the course of the data loop described above to the additional control unit 42 where the test section 52 determines that the additional control unit memory 44 is empty. The value of the tolerance class information is thereupon stored in the additional control unit memory 44 and is thus again available to the data loop. One of the advantages of the invention thus consists of the fact that, if the control unit 30 is replaced or is reset for another reason and the information in the control unit memory 46 is lost, the tolerance class information is still present in the additional control unit 42 and it can be utilized. In the converse case, the tolerance class information can be utilized in the control unit 30 . The concept in accordance with the disclosure with the storage of the tolerance class information both in the additional control unit 42 and in the control unit 30 is thus based on the principle of redundancy in order to always allow a precise control of the transfer case 20 . The additional control unit 42 and the clutch actuator 40 frequently form one module and are replaced together in case of service. In this case, it is advantageous if the tolerance class information is composed of information with respect to the friction clutch 38 and information with respect to the clutch actuator 40 . A newly inserted module only comprises a piece of partial information with respect to the clutch actuator 40 in the case of replacement, whereas the part of the additional control unit memory 44 provided for the tolerance class information of the friction clutch 38 is empty or is flagged as “empty”. On a repeat initialization after the replacement of the module, only the tolerance class information of the clutch actuator 40 is overwritten in the control unit memory 46 . The tolerance class information of the friction clutch 38 is maintained and is transmitted to the additional control unit 42 where the test section 52 finds that no tolerance class information of the friction clutch 38 is present in the additional control unit memory 44 . This information is then written to the additional control unit memory 44 , whereby complete tolerance class information is again present there. If the module of clutch actuator 40 and additional control unit 42 is replaced, a replacement module is frequently used that may not be equipped with an individually determined tolerance class value of the clutch actuator 40 since an individual determination of the tolerance class for each spare part is too costly. In this case, a tolerance class value of the clutch actuator 40 is stored in the additional control unit memory 44 that characterizes a typical or “average” clutch actuator 40 . It is easy to see that the tolerance class information may include more than two pieces of partial information if a plurality of components cooperate to produce an adjustment movement or an actuation. With particularly demanding applications, however, the additional effort and/or cost described above may be justified. Provision may also be made that it is not tolerance class information that is exchanged between the units 30 and 42 , but rather the characteristics of the respective components themselves. The disclosure has been described by way of example with reference to a transfer case 20 of a motor vehicle that is characterized by tolerance class information; however, the principles of the disclosure may also be used in other systems of a motor vehicle. A series of applications also result outside automotive engineering in which the taking into account of individual features and characteristics of specific assemblies—or individual components thereof—is important. The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.
A method for the control of an assembly by a control unit, in particular in a motor vehicle, wherein the assembly includes at least one component, at least one actuator associated with the component, and an additional control unit having a first non-volatile memory section that is connected to the control unit. The control unit includes a second non-volatile memory section. Classification information associated with the assembly and stored in the first non-volatile memory section is read out and transmitted to the control unit. The transmitted classification information is stored in the second non-volatile memory section. Subsequently, the classification information stored in the second, non-volatile memory section is read out and transmitted to the additional control unit. The disclosure furthermore relates to an assembly group that comprises the assembly and the control unit, with the control unit and the additional control unit of the assembly being connected to one another by a data transmission path.
Summarize the patent document, focusing on the invention's functionality and advantages.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit and priority of German Patent Application No. 10 2007 062 675.6, filed Dec. 24, 2007.", "The entire disclosure of the above application is incorporated herein by reference.", "FIELD The present disclosure relates to a method for the control of an assembly by a control unit, in particular in a motor vehicle.", "The assembly includes at least one component, at least one actuator associated with the component, and an additional control unit having a first non-volatile memory section that is connected to the control unit, with the control unit including a second non-volatile memory section.", "BACKGROUND This section provides background information related to the present disclosure which is not necessarily prior art.", "An assembly of this kind may be a transfer case, for example, that allows a direct distribution of a driving torque between two wheels of an axle of the motor vehicle and/or—with an all-wheel drive vehicle—a direct distribution of the driving torque between a front axle and a rear axle of the motor vehicle.", "Such assemblies have to be controlled with high accuracy to be able to carry out the distribution of the driving torque with the required precision.", "However, hardly avoidable tolerances occur in their manufacture that result in deviations in the response behavior of the assemblies.", "These deviations are determined individually for the purpose of a calibration, with a respective tolerance class being associated with the assemblies in accordance with a predetermined classification scheme.", "The respectively determined tolerance class of a specific assembly may be taken into account by the associated control unit of the vehicle to control the assembly with the desired precision.", "There is a problem in connection with a classification of controllable assemblies—whether in automotive engineering or in other fields—in that the respective assembly and the control unit associated therewith are sometimes installed independently of one another.", "A teach-in process therefore usually takes place after the installation of the assembly and the control unit in which the respective then current classification of the assembly used is communicated to the control unit and is stored in it.", "If a replacement or repair of the assembly and/or of the control unit takes place later, for example in case of service, the teach-in process has to be carried out again so that the correct control of the assembly by the control unit is in turn ensured.", "It has already been proposed to encode the classification of an assembly with the help of an additional coding plug.", "DE 103 33 651 A1, for example, describes a coding plug that can be connected directly or indirectly to a control unit and which has a fixed electric circuit.", "A defined electrical state may be generated by the fixed circuit in the control unit and the state is detected and compared with stored data.", "The electrical state is then associated with a tolerance class of the assembly that may in turn be used for the adaptation of maps/characteristics for the control of the assembly.", "It is, however, disadvantageous with this solution that an additional failure risk of the controllable assembly arises due to the coding plug made as an additional component.", "Furthermore, the reading out, decoding and comparing of the classification information stored in the circuit of the coding plug may only be realized in a relatively complex and/or expensive manner.", "In addition, the coding plug likewise has to be replaced on a change of the tolerance class of the assembly.", "Ultimately, it thus cannot be precluded that a coding plug is connected to the controllable assembly that contains an incorrect classification so that the classification read out of the coding plug by the control unit does not reflect the correct tolerance class of the assembly.", "The control of the assembly is thereby even made worse under certain circumstances—in comparison with a control solution without any consideration of the tolerance class.", "SUMMARY This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.", "It is an object of the present disclosure to provide a method for the control of an assembly that ensures in a simple and reliable manner that the assembly is controlled by the control unit while taking account of the respective then current classification information.", "It is furthermore an object of the present disclosure to provide an assembly group that includes a controllable assembly and a control unit that may be operated in a corresponding manner reliably and while taking account of the respective then current classification information.", "As already initially mentioned, the present disclosure relates to a method for the control of an assembly by a control unit, wherein the assembly includes at least one component, at least one actuator associated with the component, and an additional control unit having a first non-volatile memory section and which is connected to the control unit, with the control unit including a second non-volatile memory section.", "In accordance with the disclosure, classification information associated with the assembly and stored in the first non-volatile memory section is read out and transmitted to the control unit.", "The transmitted classification information is stored in the second non-volatile memory section.", "Subsequently, the classification information stored in the second non-volatile memory section is read out and transmitted to the additional control unit.", "In other words, a bidirectional exchange of classification information takes place between the additional control unit and the control unit, with it not being significant which of the two units actively initiates or carries out the transmission of the classification information.", "It is, for example, possible that a respective one of the control units is responsible for one of the transmission directions or that one of the control units controls both transmission directions.", "It is, however, important that the classification information stored in the first non-volatile memory section is stored after the reading out and the transmission to the control unit in the second non-volatile memory section there.", "This classification information is read out again and is transmitted back to the additional control unit.", "Generally, the method may also start with the reading out of the memory content of the second non-volatile memory section and with the transmission of the classification information to the additional control unit.", "The data exchange between the control unit and the additional control unit ensures that classification information associated with the actually installed assembly is always exchanged.", "For example, on a change of the classification information stored in the first non-volatile memory section, the classification information is transmitted to the control unit by the method in accordance with the disclosure and is stored there in its second non-volatile memory section.", "The classification information transmitted back to the additional control unit may be used, for example, for comparison purposes, test purposes, or other purposes.", "After the transmission of the classification information in the control unit, the new classification is in every case present there and may be used, for example, for optimization of the assembly control.", "The classification information transmitted to the additional control unit is preferably stored in the first non-volatile memory section if the first non-volatile memory section does not contain any classification information.", "This may be the case, for example, if the additional control unit was replaced or if the memory content of the first non-volatile memory section was deleted.", "The additional control unit then receives the classification information stored in the second non-volatile memory section of the control unit, whereby the data loop is again completed.", "In a further embodiment of the present disclosure, the classification information transmitted to the additional control unit is not stored in the first non-volatile memory section if the first non-volatile memory section already contains classification information.", "This, for example, prevents the overwriting of previously stored and assembly-specific classification information.", "The non-stored classification information may be ignored or may be further processed for comparison purposes.", "In a preferred embodiment of the present invention, the classification information is used by the control unit for the adaptation of at least one map or of at least one characteristic to improve the control of the assembly.", "The relationship stored in the control unit between a control signal and the thereby generated response of the assembly may, for example, be modified in dependence on the classification information to obtain a corrected relationship that allows a more precise control of the assembly.", "Provision may furthermore be made that the classification information is composed of at least two pieces of partial information, with one of the pieces of partial information being associated with the component as a component classification and the other piece of partial information being associated with the actuator as an actuator classification.", "This allows an even more individual taking into account of the individual components of the assembly on its control.", "Changes in the tolerance class of the component and/or of the actuator—for instance, on a repair or a replacement of the component and/or of the actuator—may thereby, for example, be taken into account separately from one another.", "Further components of the assembly may likewise be taken into account by corresponding pieces of partial information.", "Generally, pieces of partial information may also be provided that do not contain any tolerance class information, such as serial numbers or the like.", "In accordance with a further embodiment of the method in accordance with the disclosure, the pieces of partial information of the classification information stored in the second non-volatile memory section are overwritten by the corresponding pieces of partial information transmitted to the control unit, whereby it is prevented that different pieces of information that may differ from one another are collected in the second non-volatile memory section.", "The then currently valid pieces of partial information are therefore always present in the control unit due to the overwriting.", "It must be noted in this connection that in each case only the corresponding pieces of partial information are overwritten by new pieces of partial information, (i.e., a stored value of the then current component classification should, for example, not be overwritten by a value of the actuator classification, but rather the component classification value stored in the second non-volatile memory section should be overwritten by the component classification value transmitted by the additional control unit).", "A comparison of the stored component classification value with the transmitted component classification value before the storing is not necessary in this respect.", "A check only has to be made whether the transmitted component classification value is “empty”", "or is flagged as “empty”, for example by the value “0.”", "If the transmitted classification information contains, for example, only a first piece of partial information (i.e., a second piece of partial information is “empty”", "or is flagged as an “empty”", "piece of partial information) only the transmitted first piece of partial information is used for the overwriting of the first piece of partial information stored in the second non-volatile memory section.", "A second piece of partial information stored there is not overwritten or changed.", "It is preferred that the actuator and the additional control unit associated with it are replaced by a replacement actuator and by a replacement additional control unit associated with it in case of service, with its first non-volatile memory section only including the actuator classification.", "In other words, the first non-volatile memory sections does not contain any component classification if the component was not replaced in the course of the servicing.", "In accordance with the method in accordance with the disclosure, the valid component classification is still stored in the control unit and, after the replacement of the actuator and of the additional control unit, it is again transmitted to the latter and is stored there to complete the data loop.", "It is preferred if, in the case described above, the actuator classification includes information characterizing a typical actuator or information individually determined for the replacement actuator.", "The first variant is particularly cost-effective since it only provides for the storage of an actuator classification of a typical or “average”", "actuator.", "Costs are saved due to the waiving of an individual characterization of the replacement actuator and the storage of the corresponding actuator classification, while an at least “averagely”", "good control of the actuator still remains possible.", "The second variant in contrast allows a more precise control of the assembly;", "however, it is associated with an increased effort and/or cost.", "It is generally possible that, on a replacement of the component and/or of the actuator without a replacement of the additional control unit, the component classification and/or the actuator classification are each replaced by information that characterizes a typical component or a typical actuator or that was determined individually for the component or for the replacement actuator.", "The procedure of the first variant includes, for example, a resetting of the additional control unit to default values of the component classification and of the actuator classification since the obsolete classifications associated with the previously used components could result in worse control results in interaction with the new components.", "The second variant in contrast allows a more precise control of the assembly;", "however, it is associated with an increased effort and/or cost.", "In accordance with a further embodiment of the method in accordance with the disclosure, the pieces of partial information transmitted to the additional control unit are not stored in the first non-volatile memory section if the first non-volatile memory section already contains values for the corresponding piece of partial information.", "In other words, a check is made whether the parts of the first non-volatile memory section associated with the individual pieces of partial information are “empty”", "or are flagged as “empty”—for example by the value “0”—before a storage of the corresponding piece of partial information takes place.", "It should be prevented in this way that information stored in the additional control unit is overwritten.", "Provision may furthermore be made that the pieces of partial information transmitted to the additional control unit is stored in the first non-volatile memory section if the first non-volatile memory section does not contain any values for the corresponding pieces of partial information.", "In this variant of the method, in particular the total classification information is stored if only the additional control device was replaced and does not have an empty first non-volatile memory section, or a first non-volatile memory section flagged as “empty”, but the actuator and the component were not replaced.", "In this case, the memory content of the first non-volatile memory section is updated again by the data transmitted by the control unit.", "It has proved to be advantageous if the classification information associated with the assembly and/or the pieces of partial information associated with the individual components of the assembly is/are determined ex works (i.e., where the individual components are manufactured) and is/are stored in the first non-volatile memory section.", "The transmission of the classification information to the control unit can take place at predetermined times or after reception of a request signal.", "This can, for example, be done regularly or after an initialization at the start of an ignition procedure of the vehicle.", "Furthermore, the transmission of the classification information to the additional control unit may also take place at predetermined times or after reception of a request signal, in particular after reception of data from the additional control unit or at regular intervals.", "The classification information preferably includes information on the tolerance class of the component and/or of the actuator, in particular to adapt at least one map/one characteristic to control the assembly.", "A more complex and/or expensive embodiment, but one that allows a particularly precise control of the assembly, provides that the classification information includes a map/a characteristic of the assembly, of the component and/or of the actuator.", "For example, a torque characteristic is transmitted which covers the total torque range of a torque transmission clutch.", "As already initially mentioned, the present disclosure also relates to an assembly group that has a controllable assembly and a control unit, in particular for a motor vehicle, with the controllable assembly including at least one component, at least one actuator associated with the component and an additional control unit having a first non-volatile memory section, with the control unit including a second non-volatile memory section and with the control unit and the additional control unit being connected to one another by a data transmission path.", "In accordance with the disclosure, the first non-volatile memory section is made for the storage of classification information associated with the assembly, whereas the data transmission path is designed such that the classification information may be transmitted from the additional control unit to the control unit and vice versa.", "The control unit is made for the transmission of the classification information to the additional control unit.", "A two-way transmission of the classification information between the additional control unit and the control unit is thereby made possible in order, for instance, also always to have current classification information present after a case of servicing.", "The additional control unit preferably includes a test unit that is made to check the memory content of the first non-volatile memory section and to store the classification information, or parts thereof, transmitted to the additional control unit in the first non-volatile memory section if no classification information or if incomplete classification information is stored in the first non-volatile memory section—for instance, classification information not including all pieces of partial information.", "In other words, it is determined by the test unit whether the memory content of the first non-volatile memory section is “empty”", "or is flagged as “empty”—in part or in total.", "In this respect, it is not the stored value of the information which is important, but rather whether this information is present at all, with it having to be pointed out in this connection that specific values—such as “0”—can only serve as a flag to indicate that the corresponding information is not present.", "If no partial information or no corresponding pieces of partial information is/are present, this is stored in the first non-volatile memory section.", "The test unit thus ensures that always current information is stored in the additional control unit.", "In addition, the control unit may include a memory unit which is made to overwrite the classification information, or parts thereof, stored in the second non-volatile memory section by the classification information, or corresponding parts thereof, transmitted by the additional control unit.", "The information present in the control unit is updated by the overwriting.", "This procedure moreover saves memory space.", "In accordance with an embodiment of the assembly group in accordance with the information, some of the pieces of classification information may be transmitted over the data transmission path and/or may be stored in and/or read out of the first and second non-volatile memory sections independently of one another.", "The component is preferably a torque transmission clutch.", "The assembly may be a transfer case.", "Further areas of applicability will become apparent from the description provided herein.", "The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.", "DRAWINGS The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.", "FIG. 1 is a schematic representation of a part of a motor vehicle with a controllable assembly made in accordance with the disclosure;", "and FIG. 2 is a schematic design of a controllable assembly made in accordance with the disclosure with a control unit connected thereto.", "Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.", "DETAILED DESCRIPTION Example embodiments will now be described more fully with reference to the accompanying drawings.", "A powertrain 10 of a motor vehicle having a drive 12 is shown schematically in FIG. 1 .", "The drive 12 includes an engine 14 and a transmission 16 that is connected to a transfer case 20 via a drive shaft 18 .", "The transfer case 20 serves to distribute the driving torque of the engine 14 as required via output shafts 36 to a front axle 22 and/or to a rear axle 24 of the vehicle.", "Depending on the driving situation, the driving torque may, for example, only be transferred by the transfer case 20 to one of the axles 22 , 24 or to both axles 22 , 24 in variable proportions.", "The axles 22 , 24 each include a differential unit 26 that is provided for the compensation of speed differences between wheels 28 .", "To be able to influence the different driving situations of the vehicle, the vehicle has a control unit 30 that receives information on the state and on the movements of the vehicle and its environment via a plurality of sensors (not shown).", "This data is logged and evaluated by the control unit 30 .", "The evaluation of the data allows the generation of control signals that are in turn transmitted to the components of the vehicle to control the vehicle in the desired manner.", "For example, control lines 50 are shown in FIG. 1 which connect the control unit 30 to the engine 14 , to the transmission 16 , and to the transfer case 20 .", "A data bus, in particular a CAN bus, may also be provided instead of separate control lines 50 .", "The control signals are in particular present in a digital format.", "FIG. 2 is a very simplified schematic representation of the transfer case 20 and of the control unit 30 connected thereto.", "The transfer case 20 includes a transfer case unit 34 that allows a torque of the drive shaft 18 to be distributed selectively to the output shafts 36 that are connected to the respective differential unit 26 of the front axle 22 or of the rear axle 24 , respectively (see FIG. 1 ).", "The selective distribution of the torque of the drive shaft 18 depends on the state of a friction clutch 38 of the transfer case unit 34 .", "For example, the driving torque is only transmitted to the rear axle 24 with an open friction clutch 38 .", "To transmit some of the driving torque to the front axle 22 as well, the friction clutch 38 is brought into engagement at least partially.", "In other words, the portion of the driving torque transmitted to the front axle 22 is a function of the degree of actuation of the friction clutch 38 .", "The precise actuation of the clutch 38 is thus of great significance to allow a precisely defined distribution of the driving torque to the axles 22 , 24 .", "It must be taken into account in this connection that each friction clutch 38 has production-induced properties.", "This likewise applies to a clutch actuator 40 that can selectively bring the friction clutch 38 into engagement (i.e., the friction clutch 38 and the clutch actuator 40 respond to a given control signal in a characteristic manner which differs from other friction clutches 38 or clutch actuators 40 basically of the same construction).", "These practically unavoidable differences originate, for example, in manufacture-induced production tolerances and/or in slight variations of the properties of the material used.", "To ensure the desired distribution of the driving torque with the required precision, it is necessary to take the characteristics of each transfer case 20 into account individually and to adapt the control signals supplied to it accordingly.", "This is effected in that the individual components of the transfer case 20 are measured individually or in total at the end of production (i.e., the response of the components or of the total transfer case 20 to specific control signals is observed and a special characteristic is determined).", "This is in particular characterized by the torque transmission characteristics of the friction clutch 38 and the behavior of the clutch actuator 40 .", "The specific characteristics are associated with one of a plurality of tolerance classes.", "The control signals for the transfer case 20 may be adapted with reference to the specific tolerance class—for instance by adaptation of maps/characteristics—to achieve a distribution of the driving torque which is as exact as possible.", "The control signals of the control unit 30 are supplied to the clutch actuator 40 via an additional control unit 42 and via a control line 50 ′.", "The additional control unit 42 has an additional control unit memory 44 in which the tolerance class described above is stored.", "The control signals transmitted by the control unit 30 may be adapted in the additional control unit 42 while taking the tolerance class into account to be able to provide adapted control signals to the clutch actuator 40 .", "It is expedient, however, to make the additional control unit 42 as simple as possible and to carry out the correction of the control signals in the control unit 30 .", "For this purpose, the control unit 30 must be supplied with the corresponding tolerance class information.", "This is done by the additional control unit 42 reading out the tolerance class information from the additional control unit memory 44 and transmitting it to the control unit 30 .", "This information may be stored in a control unit memory 46 by a control unit 54 .", "The information stored in the control unit memory 46 is used for the adaptation of characteristics 48 that are used for the generation of control signals for the transfer case 20 .", "The tolerance class information stored in the control unit memory 46 is subsequently again transmitted to the additional control unit 42 via the control line 50 , whereupon the memory content of the additional control unit memory 44 is checked by a test section 52 .", "If the additional control unit memory 44 already has a stored value, the value transmitted by the control unit 30 is ignored.", "If the additional control unit memory 44 is, however, empty or is flagged as “empty”, the transmitted information is written into the additional control unit memory 44 .", "The process subsequently starts again with the reading out and the transmission of the information stored in the additional control unit memory 44 to the control unit 30 .", "An exchange of information between the additional control unit 42 and the control unit 30 thus takes place at predetermined times, at regular intervals or in response to request signals.", "The exchange of data is in particular of importance after an initialization at the start of an ignition procedure of the vehicle.", "If a tolerance class determined ex works (i.e., where the individual components are manufactured) was stored in the additional control unit memory 44 , the correct value is stored in the control unit memory 46 of the control unit 30 after a first transmission of this information.", "The value of the tolerance class transmitted back to the additional control unit 42 , therefore, agrees with the originally stored value.", "As described above, this tolerance class information is ignored since the additional control unit memory 44 already contains corresponding information.", "If, however, the additional control unit 42 was removed and replaced by a new additional control unit 42 , the additional control unit memory 44 is empty or is flagged as “empty.”", "On a take-up of communication between the new additional control unit 42 and the control unit 30 , no information is transmitted from the additional control unit 42 to the control unit 30 .", "However, the correct tolerance class information of the friction clutch 38 and of the clutch actuator 40 is still contained in the control unit memory 46 .", "This information is transmitted in the course of the data loop described above to the additional control unit 42 where the test section 52 determines that the additional control unit memory 44 is empty.", "The value of the tolerance class information is thereupon stored in the additional control unit memory 44 and is thus again available to the data loop.", "One of the advantages of the invention thus consists of the fact that, if the control unit 30 is replaced or is reset for another reason and the information in the control unit memory 46 is lost, the tolerance class information is still present in the additional control unit 42 and it can be utilized.", "In the converse case, the tolerance class information can be utilized in the control unit 30 .", "The concept in accordance with the disclosure with the storage of the tolerance class information both in the additional control unit 42 and in the control unit 30 is thus based on the principle of redundancy in order to always allow a precise control of the transfer case 20 .", "The additional control unit 42 and the clutch actuator 40 frequently form one module and are replaced together in case of service.", "In this case, it is advantageous if the tolerance class information is composed of information with respect to the friction clutch 38 and information with respect to the clutch actuator 40 .", "A newly inserted module only comprises a piece of partial information with respect to the clutch actuator 40 in the case of replacement, whereas the part of the additional control unit memory 44 provided for the tolerance class information of the friction clutch 38 is empty or is flagged as “empty.”", "On a repeat initialization after the replacement of the module, only the tolerance class information of the clutch actuator 40 is overwritten in the control unit memory 46 .", "The tolerance class information of the friction clutch 38 is maintained and is transmitted to the additional control unit 42 where the test section 52 finds that no tolerance class information of the friction clutch 38 is present in the additional control unit memory 44 .", "This information is then written to the additional control unit memory 44 , whereby complete tolerance class information is again present there.", "If the module of clutch actuator 40 and additional control unit 42 is replaced, a replacement module is frequently used that may not be equipped with an individually determined tolerance class value of the clutch actuator 40 since an individual determination of the tolerance class for each spare part is too costly.", "In this case, a tolerance class value of the clutch actuator 40 is stored in the additional control unit memory 44 that characterizes a typical or “average”", "clutch actuator 40 .", "It is easy to see that the tolerance class information may include more than two pieces of partial information if a plurality of components cooperate to produce an adjustment movement or an actuation.", "With particularly demanding applications, however, the additional effort and/or cost described above may be justified.", "Provision may also be made that it is not tolerance class information that is exchanged between the units 30 and 42 , but rather the characteristics of the respective components themselves.", "The disclosure has been described by way of example with reference to a transfer case 20 of a motor vehicle that is characterized by tolerance class information;", "however, the principles of the disclosure may also be used in other systems of a motor vehicle.", "A series of applications also result outside automotive engineering in which the taking into account of individual features and characteristics of specific assemblies—or individual components thereof—is important.", "The foregoing description of the embodiments has been provided for purposes of illustration and description.", "It is not intended to be exhaustive or to limit the invention.", "Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described.", "The same may also be varied in many ways.", "Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention." ]
This Application claims priority to a pending U.S. patent application having Ser. No. 11/254,520 filed on 20 Oct. 2005. This Application is a Continuation in Part. The present invention relates to an enteral feeding set and in particular an enteral feeding set for connection to an automatic pump system wherein a fluid to be supplied to a patient is automatically selectable from one of two fluid sources. Feeding sets with more than one connection to a fluid source are known. For example, Tyco Healthcare has marketed an enteral feeding set (product code no. 717324) for connection to a pump having two tubes from two connectors leading to a single Y-connection. Each of the tubes may be individually clamped shut. An enteral feeding set incorporating two fluid sources is shown in WO 2005/115501, the contents of which are incorporated by reference herein in their entirety. This document teaches the use of a flow control apparatus which controls the operation of a valve for selecting one of the fluid sources for fluid supply to a patient. Another arrangement incorporating two fluid sources is described in WO 98/046293. A wide variety of connectors for connecting enteral feeding sets to fluid sources are known. Examples include a sliding seal adapter described in WO 2004/017852 and a connector including a spike for piercing a foil seal described in EP 1 063 956. It is an object of the invention to provide an enteral feeding set for connection to two different fluid sources in a manner such that a correct correction of a fluid source can be more reliably made. SUMMARY OF THE INVENTION The present invention provides in a first aspect an enteral feeding set comprising tubing adapted for fluid flow therethrough and further adapted to be engaged by a pump unit, a valve mechanism in direct communication with said tubing, said valve mechanism being adapted to be engaged by said pump unit, and a feeding set indicator for permitting identification of the functional configuration of said administration feeding set by said pump unit, characterized in that said tubing comprises at least two inlet tubes on an upstream side of said valve mechanism and a single outlet tube on a downstream side thereof and wherein said inlet tubes each include a connector for connecting said tube to a supply of fluid at a connection end thereof, each of said connectors being of like form but visually distinguishable for indicating to a user which supply of fluid each connector should be attached thereto. In a second aspect, there is provided an enteral feeding set comprising tubing adapted for fluid flow therethrough and further adapted to be engaged by a pump unit, a valve mechanism in direct communication with said tubing, said valve mechanism being adapted to be engaged by said pump unit, and a feeding set indicator for permitting identification of the functional configuration of said administration feeding set by said pump unit, characterized in that said tubing comprises at least two inlet tubes on an upstream side of said valve mechanism and a single outlet tube on a downstream side thereof and wherein a first inlet tube includes a connector at a connection end thereof for connecting said first inlet tube to a substantially rigid fluid container and a second inlet tube is connected to a pliable fluid container. The connectors of the enteral feeding sets of the invention may incorporate a projection for puncturing a seal on a fluid source in the form of a knife edge which punctures the seal and then, as the connector is being attached to the fluid source by means of a threaded coupling cuts the seal open to provide an opening in the seal which will not become blocked. Preferably, an air vent incorporating a microbial filter is also included. Sliding seal connectors may also be used. In order to avoid an operator connecting fluid sources to the wrong tubing, the connectors may be colour coded such as to match a corresponding colour marking on a fluid container. In a still further aspect of the invention, there is provided an enteral feeding set comprising a flush connector adapted to be coupled to a flush container holding a flush fluid therein, the flush connector comprising a first connector body, and a first liquid passage defined in the first connector body, the first liquid passage being in fluid communication with the flush container when the flush connector is coupled to the flush container, the first connector body further comprising a first spike extending outward for piercing a puncturable seal within the flush container, and a first air passage defined in the first connector body, the first air passage being coupled in fluid communication with the flush container for introducing air into the flush container; flush tubing coupled in fluid communication to the first liquid passage for receiving a flow of the flush fluid from the flush container; a feed connector adapted to be coupled to a feed container holding an enteral feed fluid therein, the feed connector comprising a second connector body, and a second liquid passage defined in the second connector body, the second liquid passage being in fluid communication with the feed container when the feed connector is coupled to the feed container, the second connector body further comprising a second spike extending outward for piercing a puncturable seal within the feed container, and a second air passage defined in the second connector body, the second air passage being coupled in fluid communication with the feed container for introducing air into the feed container; feed tubing coupled in fluid communication to the second liquid passage for receiving a flow of the enteral feed fluid from the feed container; and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet. In another aspect, there is provided an enteral feed set comprising a generally flexible flush bag adapted to hold a flush fluid therein; the flush tubing coupled in fluid communication with the flexible flush bag for receiving a flow of the flush fluid therefrom; a feed connector adapted to be coupled to a feed container holding an enteral feed fluid therein, the feed connector comprising a connector body, and a liquid passage defined in the connector body, the liquid passage being in fluid communication with the feed container when the feed connector is coupled to the feed container, the connector body further comprising a spike extending outward for piercing a puncturable seal within the feed container, and an air passage defined in the connector body, the air passage being coupled in fluid communication with the feed container for introducing air into the feed container; feed tubing coupled in fluid communication to the liquid passage of the feed connector for receiving a flow of the enteral feed fluid from the feed container; and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet. A further aspect of the invention is an enteral feed set comprising a flush adapter configured to be coupled in fluid communication to a flush container holding a flush fluid therein, the flush adapter comprising a first adapter body, a first spike member, a first spring, a first collar member, and a first sliding shaft seal, the first adapter body having a first annular flange, the first spike member being coupled with the first adapter body and including a first tube adapter, the first spring being disposed within the first adapter body for applying a spring force against the first spike member, the first collar member including a first annular groove configured to securely engage the first annular flange, the first sliding shaft seal being disposed at least partially within the first adapter body and being configured to slidingly engage in fluid tight engagement with the first spike member; flush tubing coupled in fluid communication to the first tube adapter for receiving a flow of the flush fluid from the flush container; a feed adapter configured to be coupled in fluid communication to a feed container holding an enteral feed fluid therein, the feed adapter comprising a second adapter body, a second spike member, a second spring, a second collar member, and a second sliding shaft seal, the second adapter body having a second annular flange, the second spike member being coupled with the second adapter body and including a second tube adapter, the second spring being disposed within the second adapter body for applying a spring force against the second spike member, the second collar member including a second annular groove configured to securely engage the second annular flange, the second sliding shaft seal being disposed at least partially within the second adapter body and being configured to slidingly engage in fluid tight engagement with the second spike member; feed tubing coupled in fluid communication to the second tube adapter for receiving a flow of the enteral feed fluid from the feed container; and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet. BRIEF INTRODUCTION TO THE DRAWINGS Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIG. 1 is a schematic illustration of an enteral feed set for connection to two fluid sources; FIG. 2 is a perspective of a connector for connecting an enteral container of liquid nutrients to an enteral feeding tube; FIG. 3 is a vertical section of the connector; FIG. 4 is a vertical section of the connector snapped into to a small outlet container and attached to an enteral feeding tube; FIG. 5 is a vertical section of the connector threaded onto a large outlet container and attached to an enteral feeding tube; FIG. 6 is fragmentary exploded perspective of the large outlet container, the connector and the enteral feeding tube; FIG. 7 is a bottom plan view of the connector; FIG. 8 is a front elevation of the connector with a portion of a body of the connector broken away to reveal a spike of the connector; FIG. 9 is a side elevation of the connector with a portion of the body of the connector broken away to reveal the spike; FIG. 10 is a side elevation of the connector with an air filter exploded from the connector and a mount for the filter partially broken to illustrated internal FIG. 11 is a schematic illustration of a second enteral feeding set FIG. 12 shows a sliding seal connector; and FIG. 13 is a schematic illustration of a third enteral feeding set. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an enteral feeding set 2 having two tubes 4 , 6 for connection to respective fluid sources 8 , 9 by means of respective connectors 10 . Referring now to FIGS. 2-3 , the connector 10 is shown in more detail. The connector includes a body, generally indicated at 12 , having an interior surface 14 ( FIG. 3 ) that defines a cavity 16 for receiving an outlet of the container, as explained in more detail below ( FIGS. 4-6 ). The body 12 has a cylindrical lower portion 18 and a smaller cylindrical upper portion 20 projecting upward from a top surface 22 of the lower portion. Referring to FIGS. 4-6 , the cavity 16 is configured for receiving different types of containers. As shown in FIG. 4 , the cavity 16 at the upper portion 20 is sized and shaped for snap-fit reception of a relatively small outlet 24 of a container 26 . The interior surface 14 at the upper portion 20 is elastically deformable to allow a rigid snap-fit member 27 (e.g., a projecting rim extending around the outlet 24 ) to snap-fit into the upper portion. As shown in FIG. 5 , the cavity 16 at the lower portion 18 is sized and shaped to threadably receive a relatively larger outlet 28 of a container 30 . The interior surface 14 at the lower portion 18 of the connector 10 includes internally projecting threads 32 for attaching to external threads 33 extending around the outlet 28 of the container 30 . The depth D ( FIG. 3 ) of the cavity 16 at the lower portion 18 is between about 1.40 cm and 1.80 cm. This depth D allows the connector 10 to attach to containers 30 having necks of different sizes and accommodates a more secure connection with the different containers. Further, the internal threads 32 of the lower portion 18 have a thickness T 1 of between about 0.12 cm and about 0.11 cm. Ridges 34 ( FIG. 2 ) disposed around an exterior surface of the body 12 at the lower portion 18 provide a user with adequate grip when threading the connector 10 on the container 30 . The connector 10 may be configured to attach to an outlet of a container in other ways without departing from the scope of this invention. Moreover, the connector 10 may be configured to attach only to one type of container, such as a threaded container or a snap-fit container, or the connector may be configured to attach to more than two types of containers. Referring to FIGS. 3-5 , a liquid passage 38 extends through the upper portion 20 of the body 12 and is in fluid communication with the cavity 16 . An opening 40 of the liquid passage 38 is substantially flush with an upper surface section 42 of the interior surface 14 of the body 12 (i.e., the liquid passage does not extend into the cavity 16 ), although it is contemplated that the liquid passage may extend into the cavity. In the illustrated embodiment, the upper surface section 42 is substantially flat. The liquid passage 38 also extends through a conduit 44 projecting outward from the exterior surface of the body 12 at the upper portion 20 . The conduit 44 has externally projecting threads 46 for attaching to an internally threaded adapter 52 of an enteral feeding tube 54 ( FIGS. 4-6 ). The external threads 46 of the conduit 44 have a thickness T 2 of between about 0.11 cm and about 0.06 cm. Other ways of connecting the enteral feeding tube 54 to the connector 10 , including the use of an interference fitting, is within the scope of this invention. As shown in FIGS. 4-6 , when assembled, the connector 10 is secured to the outlet 24 , 28 of the respective container 26 , 30 by either threading (as shown in FIGS. 5 and 6 ) or fitting the connector on the container ( FIG. 4 ). The threaded adapter 52 is threaded on the conduit 44 of the connector 10 . Thus, when assembled, the connector 10 fluidly connects the enteral feeding tube 54 to the attached container 26 , 30 . Referring to FIGS. 3-8 , a generally elongate spike, generally indicated at 58 , formed integrally with the body 12 projects from the upper surface section 42 of the body into the cavity 16 . The spike 58 is spaced a distance Si ( FIG. 3 ) from a central axis A B of the body 12 and a distance S 2 ( FIG. 3 ) from a longitudinal axis A O of the opening 40 of the liquid passage 38 . The spike 58 is configured to puncture a puncturable seal 60 (e.g., foil seal) ( FIGS. 4-6 ) covering the outlet 24 , 28 of the container 26 , 30 to allow the liquid nutrients to exit the container. As shown best in FIG. 7 , the spike 58 has a pair of opposite narrow sides 63 A, 63 B and a pair of opposite broad sides 63 C, 63 D extending between its length L S ( FIG. 8 ). Referring to FIGS. 7 and 8 , a bottom surface 62 of the spike 58 (i.e., at the free end of the spike) is generally flat. As shown in FIG. 8 , the bottom surface 62 is bevelled from the narrow side 63 A (broadly, a first narrow side) to the opposite narrow side 63 B (broadly, a second narrow side), such that the bottom surface lies in a plane intersecting the central axis A B of the body 12 at an angle ⊖ 1 . This bevelled configuration of the bottom surface 62 forms a sharp tip 64 for puncturing the seal 60 of the threaded container 30 . As shown in FIG. 8 , the bottom surface 62 is also bevelled from the broad side 63 C (broadly, a first broad side) to the opposite broad side 63 D (broadly, a second broad side), such that the bottom surface lies in a plane intersecting the central axis of the body A B at an angle ⊖ 2 . Referring to FIG. 8 , the narrow side 63 B is bevelled from the broad side 63 D to the opposite broad side 63 C, defining a knife edge 66 along the length L S of the spike to the tip 64 . After the seal 60 is punctured by the tip 64 , the knife edge 66 cuts the seal 60 as the connector 10 is rotated (e.g., threaded) on the outlet 24 , 28 of the container 26 , 30 . The spike 58 makes a relatively large (i.e., larger than the width of the spike 58 ), generally circular opening 70 through the seal, as illustrated in FIGS. 4 and 5 . Referring to FIGS. 7-9 , the broad side 63 D of the spike 58 is generally arcuate and joins the bevelled narrow side 63 B at folding edge 68 . The narrow side 63 B tapers toward the bottom surface 62 such that the folding edge 68 falls off or angles toward the tip 64 . As the connector 10 is rotated on the container 26 , 30 , the knife edge 66 cuts the seal 60 and forms a foil edge margin 69 ( FIGS. 3 and 4 ) defining the opening 70 . Referring to FIGS. 4 and 5 , as the connector 10 continues to rotate, the folding edge 68 of the spike 58 folds the foil edge margin 68 of the seal 60 away from the opening 70 in the seal 60 and away from the opening 40 of the liquid passage 38 so that the foil edge margin will not obstruct the openings. Referring to FIGS. 3-5 , an air passage 72 extends from the cavity 16 through the spike 58 and the upper portion 20 of the body 12 . A vacuum within the container 26 , 30 , created when the liquid exits the container, draws air into the container through the air passage 72 , thereby allowing the liquid to flow continuously and freely out of the container through the liquid passage 38 of the connector 10 . The air passage 72 opens at the bottom surface 62 of the spike 58 to communicate with the cavity 16 , although the passage may open at other locations along the length L S of the spike. Referring to FIGS. 3-5 and 9 , the air passage 72 is fluidly connected to a filter mount, generally indicated at 74 , projecting outward from the exterior surface of the body 12 at the upper portion 20 . The filter mount 74 includes a large cylindrical opening 76 ( FIG. 3 ) having a longitudinal axis Aco extending generally transverse to the central axis A B of the body 12 . A tubular duct 78 disposed within the large opening 76 extends generally coaxially therein. As shown in FIG. 3 , the duct 78 has a first open end 80 in fluid communication with the air passage 72 and a second open end 82 terminating within the large opening 76 . The large opening 76 and an exterior surface of the duct 78 define an annular socket 84 ( FIG. 3 ) making an interference fit with a tubular end 86 of a filter 88 ( FIG. 10 ) such that the filter is in fluid communication with the duct and the air passage 72 when fitted in the socket. As shown in FIGS. 2 , 4 and 5 , when the air filter 88 is received in the filter mount 74 , a filter medium 90 of the filter extends outside the mount. The entire connector 10 , excluding the air filter 88 , may be formed as a homogeneous and integral unit, such as by molding (e.g., injection molding) or by forming, including boring, from stock material. Alternatively, the connector 10 may be constructed of one or more separate components fastened together in a suitable manner. Suitable materials for making the connector 10 include polypropylene (e.g., polypropylene 535 ), polyethylene and other suitable polymers. Other material may be used, and different material may be used for the separate components of the connector 10 . Referring again to FIG. 1 , the connectors 10 are connected to first ends of respective tubes 4 and 6 . These tubes are connected at their opposite ends to a valve unit 100 which also connects to a single tube 102 at a first end thereof. The tube 102 is attached to an automated peristaltic pump (not shown) which as well as controlling the pumping of fluid through the feeding set 2 operates the valve unit 100 . A magnetic feed set identifier 104 is attached to a second end of the tube 102 and a further tube 106 leads therefrom for connection to a patient-indwelling gastrostomy device (not shown). Details of a suitable automated pump arrangement are described in WO 2005/115501, the contents of which are incorporated herein by reference. Fluid sources are attachable to the connectors 10 . In the preferred embodiment, fluid sources 8 and 9 may be connected, in which fluid source 8 contains a feeding solution and fluid source 9 contains a flushing solution. In view of the automated operation of the pump, it is important that an operator correctly connects the fluid sources to the feed set in order that the automatic pump controls the valve appropriately. In order to ensure correct matching of a particular connector 10 to a particular fluid source, in the preferred embodiment, the connectors are colour coded such that a colour of the plastic molding of the body 12 of the connector corresponds to a colour of the fluid source container, whereby the container may, for example, be appropriately coloured by colouring a screw fitting molding to which the connector 10 is attached or by a coloured foil around the fluid container. Rather than colouring the connector 10 , a coloured flag could be attached to the appropriate tube 4 and 6 for matching with an appropriate coloured container. Another solution for providing an improved enteral feeding set is an arrangement as shown in FIG. 11 . In the arrangement of FIG. 11 , rather than the connectors 10 of the FIG. 1 arrangement, the enteral feeding set 202 shown in FIG. 11 includes two sliding seal connectors 210 . The sliding seal connectors 210 are fabricated in accordance with the arrangement shown in WO 2004/017852. An expanded view of one of the connectors 210 is shown in FIG. 12 . As in the case of the feeding set 2 , the feeding set 202 provides means for correctly matching up a respective connector 210 to a respective fluid source. The preferred means in the case of the arrangement shown in FIG. 11 is to colour code one of the components forming the connector, for example a body portion 220 . Of course, a coloured flag arrangement could also be used, as with the arrangement of FIG. 1 . A still further solution for providing an improved enteral feeding set is an arrangement as shown in FIG. 13 . In this arrangement, the enteral feeding set 302 incorporates a single connector 10 in accordance with the connector shown in FIGS. 2-10 attached to one tube 306 . Second tube 308 terminates in a permanent connection to a refillable fluid bag 310 . By providing two different fluid sources, one a rigid container containing a feeding solution and a refillable bag for receiving a flushing solution, the arrangement of FIG. 13 provides an enhanced degree of security that the correct fluid solution will be provided to the correct connection tube. When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
The present invention provides an enteral feeding set comprising tubing adapted for fluid flow therethrough and further adapted to be engaged by a pump unit, a valve mechanism in direct communication with said tubing, said valve mechanism being adapted to be engaged by said pump unit, and a feeding set indicator for permitting identification of the functional configuration of said administration feeding set by said pump unit, characterized in that said tubing comprises at least two inlet tubes on an upstream side of said valve mechanism and a single outlet tube on a downstream side thereof and wherein said inlet tubes each include a connector for connecting said tube to a supply of fluid at a connection end thereof, each of said connectors being of like form but visually distinguishable for indicating to a user which supply of fluid each connector should be attached thereto.
Concisely explain the essential features and purpose of the invention.
[ "This Application claims priority to a pending U.S. patent application having Ser.", "No. 11/254,520 filed on 20 Oct. 2005.", "This Application is a Continuation in Part.", "The present invention relates to an enteral feeding set and in particular an enteral feeding set for connection to an automatic pump system wherein a fluid to be supplied to a patient is automatically selectable from one of two fluid sources.", "Feeding sets with more than one connection to a fluid source are known.", "For example, Tyco Healthcare has marketed an enteral feeding set (product code no. 717324) for connection to a pump having two tubes from two connectors leading to a single Y-connection.", "Each of the tubes may be individually clamped shut.", "An enteral feeding set incorporating two fluid sources is shown in WO 2005/115501, the contents of which are incorporated by reference herein in their entirety.", "This document teaches the use of a flow control apparatus which controls the operation of a valve for selecting one of the fluid sources for fluid supply to a patient.", "Another arrangement incorporating two fluid sources is described in WO 98/046293.", "A wide variety of connectors for connecting enteral feeding sets to fluid sources are known.", "Examples include a sliding seal adapter described in WO 2004/017852 and a connector including a spike for piercing a foil seal described in EP 1 063 956.", "It is an object of the invention to provide an enteral feeding set for connection to two different fluid sources in a manner such that a correct correction of a fluid source can be more reliably made.", "SUMMARY OF THE INVENTION The present invention provides in a first aspect an enteral feeding set comprising tubing adapted for fluid flow therethrough and further adapted to be engaged by a pump unit, a valve mechanism in direct communication with said tubing, said valve mechanism being adapted to be engaged by said pump unit, and a feeding set indicator for permitting identification of the functional configuration of said administration feeding set by said pump unit, characterized in that said tubing comprises at least two inlet tubes on an upstream side of said valve mechanism and a single outlet tube on a downstream side thereof and wherein said inlet tubes each include a connector for connecting said tube to a supply of fluid at a connection end thereof, each of said connectors being of like form but visually distinguishable for indicating to a user which supply of fluid each connector should be attached thereto.", "In a second aspect, there is provided an enteral feeding set comprising tubing adapted for fluid flow therethrough and further adapted to be engaged by a pump unit, a valve mechanism in direct communication with said tubing, said valve mechanism being adapted to be engaged by said pump unit, and a feeding set indicator for permitting identification of the functional configuration of said administration feeding set by said pump unit, characterized in that said tubing comprises at least two inlet tubes on an upstream side of said valve mechanism and a single outlet tube on a downstream side thereof and wherein a first inlet tube includes a connector at a connection end thereof for connecting said first inlet tube to a substantially rigid fluid container and a second inlet tube is connected to a pliable fluid container.", "The connectors of the enteral feeding sets of the invention may incorporate a projection for puncturing a seal on a fluid source in the form of a knife edge which punctures the seal and then, as the connector is being attached to the fluid source by means of a threaded coupling cuts the seal open to provide an opening in the seal which will not become blocked.", "Preferably, an air vent incorporating a microbial filter is also included.", "Sliding seal connectors may also be used.", "In order to avoid an operator connecting fluid sources to the wrong tubing, the connectors may be colour coded such as to match a corresponding colour marking on a fluid container.", "In a still further aspect of the invention, there is provided an enteral feeding set comprising a flush connector adapted to be coupled to a flush container holding a flush fluid therein, the flush connector comprising a first connector body, and a first liquid passage defined in the first connector body, the first liquid passage being in fluid communication with the flush container when the flush connector is coupled to the flush container, the first connector body further comprising a first spike extending outward for piercing a puncturable seal within the flush container, and a first air passage defined in the first connector body, the first air passage being coupled in fluid communication with the flush container for introducing air into the flush container;", "flush tubing coupled in fluid communication to the first liquid passage for receiving a flow of the flush fluid from the flush container;", "a feed connector adapted to be coupled to a feed container holding an enteral feed fluid therein, the feed connector comprising a second connector body, and a second liquid passage defined in the second connector body, the second liquid passage being in fluid communication with the feed container when the feed connector is coupled to the feed container, the second connector body further comprising a second spike extending outward for piercing a puncturable seal within the feed container, and a second air passage defined in the second connector body, the second air passage being coupled in fluid communication with the feed container for introducing air into the feed container;", "feed tubing coupled in fluid communication to the second liquid passage for receiving a flow of the enteral feed fluid from the feed container;", "and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet.", "In another aspect, there is provided an enteral feed set comprising a generally flexible flush bag adapted to hold a flush fluid therein;", "the flush tubing coupled in fluid communication with the flexible flush bag for receiving a flow of the flush fluid therefrom;", "a feed connector adapted to be coupled to a feed container holding an enteral feed fluid therein, the feed connector comprising a connector body, and a liquid passage defined in the connector body, the liquid passage being in fluid communication with the feed container when the feed connector is coupled to the feed container, the connector body further comprising a spike extending outward for piercing a puncturable seal within the feed container, and an air passage defined in the connector body, the air passage being coupled in fluid communication with the feed container for introducing air into the feed container;", "feed tubing coupled in fluid communication to the liquid passage of the feed connector for receiving a flow of the enteral feed fluid from the feed container;", "and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet.", "A further aspect of the invention is an enteral feed set comprising a flush adapter configured to be coupled in fluid communication to a flush container holding a flush fluid therein, the flush adapter comprising a first adapter body, a first spike member, a first spring, a first collar member, and a first sliding shaft seal, the first adapter body having a first annular flange, the first spike member being coupled with the first adapter body and including a first tube adapter, the first spring being disposed within the first adapter body for applying a spring force against the first spike member, the first collar member including a first annular groove configured to securely engage the first annular flange, the first sliding shaft seal being disposed at least partially within the first adapter body and being configured to slidingly engage in fluid tight engagement with the first spike member;", "flush tubing coupled in fluid communication to the first tube adapter for receiving a flow of the flush fluid from the flush container;", "a feed adapter configured to be coupled in fluid communication to a feed container holding an enteral feed fluid therein, the feed adapter comprising a second adapter body, a second spike member, a second spring, a second collar member, and a second sliding shaft seal, the second adapter body having a second annular flange, the second spike member being coupled with the second adapter body and including a second tube adapter, the second spring being disposed within the second adapter body for applying a spring force against the second spike member, the second collar member including a second annular groove configured to securely engage the second annular flange, the second sliding shaft seal being disposed at least partially within the second adapter body and being configured to slidingly engage in fluid tight engagement with the second spike member;", "feed tubing coupled in fluid communication to the second tube adapter for receiving a flow of the enteral feed fluid from the feed container;", "and a valve having first and second inlets coupled in fluid communication with the feed and flush tubing, respectively, and a valve outlet, the valve being selectively operable to allow and block flow through the valve outlet.", "BRIEF INTRODUCTION TO THE DRAWINGS Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: FIG. 1 is a schematic illustration of an enteral feed set for connection to two fluid sources;", "FIG. 2 is a perspective of a connector for connecting an enteral container of liquid nutrients to an enteral feeding tube;", "FIG. 3 is a vertical section of the connector;", "FIG. 4 is a vertical section of the connector snapped into to a small outlet container and attached to an enteral feeding tube;", "FIG. 5 is a vertical section of the connector threaded onto a large outlet container and attached to an enteral feeding tube;", "FIG. 6 is fragmentary exploded perspective of the large outlet container, the connector and the enteral feeding tube;", "FIG. 7 is a bottom plan view of the connector;", "FIG. 8 is a front elevation of the connector with a portion of a body of the connector broken away to reveal a spike of the connector;", "FIG. 9 is a side elevation of the connector with a portion of the body of the connector broken away to reveal the spike;", "FIG. 10 is a side elevation of the connector with an air filter exploded from the connector and a mount for the filter partially broken to illustrated internal FIG. 11 is a schematic illustration of a second enteral feeding set FIG. 12 shows a sliding seal connector;", "and FIG. 13 is a schematic illustration of a third enteral feeding set.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an enteral feeding set 2 having two tubes 4 , 6 for connection to respective fluid sources 8 , 9 by means of respective connectors 10 .", "Referring now to FIGS. 2-3 , the connector 10 is shown in more detail.", "The connector includes a body, generally indicated at 12 , having an interior surface 14 ( FIG. 3 ) that defines a cavity 16 for receiving an outlet of the container, as explained in more detail below ( FIGS. 4-6 ).", "The body 12 has a cylindrical lower portion 18 and a smaller cylindrical upper portion 20 projecting upward from a top surface 22 of the lower portion.", "Referring to FIGS. 4-6 , the cavity 16 is configured for receiving different types of containers.", "As shown in FIG. 4 , the cavity 16 at the upper portion 20 is sized and shaped for snap-fit reception of a relatively small outlet 24 of a container 26 .", "The interior surface 14 at the upper portion 20 is elastically deformable to allow a rigid snap-fit member 27 (e.g., a projecting rim extending around the outlet 24 ) to snap-fit into the upper portion.", "As shown in FIG. 5 , the cavity 16 at the lower portion 18 is sized and shaped to threadably receive a relatively larger outlet 28 of a container 30 .", "The interior surface 14 at the lower portion 18 of the connector 10 includes internally projecting threads 32 for attaching to external threads 33 extending around the outlet 28 of the container 30 .", "The depth D ( FIG. 3 ) of the cavity 16 at the lower portion 18 is between about 1.40 cm and 1.80 cm.", "This depth D allows the connector 10 to attach to containers 30 having necks of different sizes and accommodates a more secure connection with the different containers.", "Further, the internal threads 32 of the lower portion 18 have a thickness T 1 of between about 0.12 cm and about 0.11 cm.", "Ridges 34 ( FIG. 2 ) disposed around an exterior surface of the body 12 at the lower portion 18 provide a user with adequate grip when threading the connector 10 on the container 30 .", "The connector 10 may be configured to attach to an outlet of a container in other ways without departing from the scope of this invention.", "Moreover, the connector 10 may be configured to attach only to one type of container, such as a threaded container or a snap-fit container, or the connector may be configured to attach to more than two types of containers.", "Referring to FIGS. 3-5 , a liquid passage 38 extends through the upper portion 20 of the body 12 and is in fluid communication with the cavity 16 .", "An opening 40 of the liquid passage 38 is substantially flush with an upper surface section 42 of the interior surface 14 of the body 12 (i.e., the liquid passage does not extend into the cavity 16 ), although it is contemplated that the liquid passage may extend into the cavity.", "In the illustrated embodiment, the upper surface section 42 is substantially flat.", "The liquid passage 38 also extends through a conduit 44 projecting outward from the exterior surface of the body 12 at the upper portion 20 .", "The conduit 44 has externally projecting threads 46 for attaching to an internally threaded adapter 52 of an enteral feeding tube 54 ( FIGS. 4-6 ).", "The external threads 46 of the conduit 44 have a thickness T 2 of between about 0.11 cm and about 0.06 cm.", "Other ways of connecting the enteral feeding tube 54 to the connector 10 , including the use of an interference fitting, is within the scope of this invention.", "As shown in FIGS. 4-6 , when assembled, the connector 10 is secured to the outlet 24 , 28 of the respective container 26 , 30 by either threading (as shown in FIGS. 5 and 6 ) or fitting the connector on the container ( FIG. 4 ).", "The threaded adapter 52 is threaded on the conduit 44 of the connector 10 .", "Thus, when assembled, the connector 10 fluidly connects the enteral feeding tube 54 to the attached container 26 , 30 .", "Referring to FIGS. 3-8 , a generally elongate spike, generally indicated at 58 , formed integrally with the body 12 projects from the upper surface section 42 of the body into the cavity 16 .", "The spike 58 is spaced a distance Si ( FIG. 3 ) from a central axis A B of the body 12 and a distance S 2 ( FIG. 3 ) from a longitudinal axis A O of the opening 40 of the liquid passage 38 .", "The spike 58 is configured to puncture a puncturable seal 60 (e.g., foil seal) ( FIGS. 4-6 ) covering the outlet 24 , 28 of the container 26 , 30 to allow the liquid nutrients to exit the container.", "As shown best in FIG. 7 , the spike 58 has a pair of opposite narrow sides 63 A, 63 B and a pair of opposite broad sides 63 C, 63 D extending between its length L S ( FIG. 8 ).", "Referring to FIGS. 7 and 8 , a bottom surface 62 of the spike 58 (i.e., at the free end of the spike) is generally flat.", "As shown in FIG. 8 , the bottom surface 62 is bevelled from the narrow side 63 A (broadly, a first narrow side) to the opposite narrow side 63 B (broadly, a second narrow side), such that the bottom surface lies in a plane intersecting the central axis A B of the body 12 at an angle ⊖ 1 .", "This bevelled configuration of the bottom surface 62 forms a sharp tip 64 for puncturing the seal 60 of the threaded container 30 .", "As shown in FIG. 8 , the bottom surface 62 is also bevelled from the broad side 63 C (broadly, a first broad side) to the opposite broad side 63 D (broadly, a second broad side), such that the bottom surface lies in a plane intersecting the central axis of the body A B at an angle ⊖ 2 .", "Referring to FIG. 8 , the narrow side 63 B is bevelled from the broad side 63 D to the opposite broad side 63 C, defining a knife edge 66 along the length L S of the spike to the tip 64 .", "After the seal 60 is punctured by the tip 64 , the knife edge 66 cuts the seal 60 as the connector 10 is rotated (e.g., threaded) on the outlet 24 , 28 of the container 26 , 30 .", "The spike 58 makes a relatively large (i.e., larger than the width of the spike 58 ), generally circular opening 70 through the seal, as illustrated in FIGS. 4 and 5 .", "Referring to FIGS. 7-9 , the broad side 63 D of the spike 58 is generally arcuate and joins the bevelled narrow side 63 B at folding edge 68 .", "The narrow side 63 B tapers toward the bottom surface 62 such that the folding edge 68 falls off or angles toward the tip 64 .", "As the connector 10 is rotated on the container 26 , 30 , the knife edge 66 cuts the seal 60 and forms a foil edge margin 69 ( FIGS. 3 and 4 ) defining the opening 70 .", "Referring to FIGS. 4 and 5 , as the connector 10 continues to rotate, the folding edge 68 of the spike 58 folds the foil edge margin 68 of the seal 60 away from the opening 70 in the seal 60 and away from the opening 40 of the liquid passage 38 so that the foil edge margin will not obstruct the openings.", "Referring to FIGS. 3-5 , an air passage 72 extends from the cavity 16 through the spike 58 and the upper portion 20 of the body 12 .", "A vacuum within the container 26 , 30 , created when the liquid exits the container, draws air into the container through the air passage 72 , thereby allowing the liquid to flow continuously and freely out of the container through the liquid passage 38 of the connector 10 .", "The air passage 72 opens at the bottom surface 62 of the spike 58 to communicate with the cavity 16 , although the passage may open at other locations along the length L S of the spike.", "Referring to FIGS. 3-5 and 9 , the air passage 72 is fluidly connected to a filter mount, generally indicated at 74 , projecting outward from the exterior surface of the body 12 at the upper portion 20 .", "The filter mount 74 includes a large cylindrical opening 76 ( FIG. 3 ) having a longitudinal axis Aco extending generally transverse to the central axis A B of the body 12 .", "A tubular duct 78 disposed within the large opening 76 extends generally coaxially therein.", "As shown in FIG. 3 , the duct 78 has a first open end 80 in fluid communication with the air passage 72 and a second open end 82 terminating within the large opening 76 .", "The large opening 76 and an exterior surface of the duct 78 define an annular socket 84 ( FIG. 3 ) making an interference fit with a tubular end 86 of a filter 88 ( FIG. 10 ) such that the filter is in fluid communication with the duct and the air passage 72 when fitted in the socket.", "As shown in FIGS. 2 , 4 and 5 , when the air filter 88 is received in the filter mount 74 , a filter medium 90 of the filter extends outside the mount.", "The entire connector 10 , excluding the air filter 88 , may be formed as a homogeneous and integral unit, such as by molding (e.g., injection molding) or by forming, including boring, from stock material.", "Alternatively, the connector 10 may be constructed of one or more separate components fastened together in a suitable manner.", "Suitable materials for making the connector 10 include polypropylene (e.g., polypropylene 535 ), polyethylene and other suitable polymers.", "Other material may be used, and different material may be used for the separate components of the connector 10 .", "Referring again to FIG. 1 , the connectors 10 are connected to first ends of respective tubes 4 and 6 .", "These tubes are connected at their opposite ends to a valve unit 100 which also connects to a single tube 102 at a first end thereof.", "The tube 102 is attached to an automated peristaltic pump (not shown) which as well as controlling the pumping of fluid through the feeding set 2 operates the valve unit 100 .", "A magnetic feed set identifier 104 is attached to a second end of the tube 102 and a further tube 106 leads therefrom for connection to a patient-indwelling gastrostomy device (not shown).", "Details of a suitable automated pump arrangement are described in WO 2005/115501, the contents of which are incorporated herein by reference.", "Fluid sources are attachable to the connectors 10 .", "In the preferred embodiment, fluid sources 8 and 9 may be connected, in which fluid source 8 contains a feeding solution and fluid source 9 contains a flushing solution.", "In view of the automated operation of the pump, it is important that an operator correctly connects the fluid sources to the feed set in order that the automatic pump controls the valve appropriately.", "In order to ensure correct matching of a particular connector 10 to a particular fluid source, in the preferred embodiment, the connectors are colour coded such that a colour of the plastic molding of the body 12 of the connector corresponds to a colour of the fluid source container, whereby the container may, for example, be appropriately coloured by colouring a screw fitting molding to which the connector 10 is attached or by a coloured foil around the fluid container.", "Rather than colouring the connector 10 , a coloured flag could be attached to the appropriate tube 4 and 6 for matching with an appropriate coloured container.", "Another solution for providing an improved enteral feeding set is an arrangement as shown in FIG. 11 .", "In the arrangement of FIG. 11 , rather than the connectors 10 of the FIG. 1 arrangement, the enteral feeding set 202 shown in FIG. 11 includes two sliding seal connectors 210 .", "The sliding seal connectors 210 are fabricated in accordance with the arrangement shown in WO 2004/017852.", "An expanded view of one of the connectors 210 is shown in FIG. 12 .", "As in the case of the feeding set 2 , the feeding set 202 provides means for correctly matching up a respective connector 210 to a respective fluid source.", "The preferred means in the case of the arrangement shown in FIG. 11 is to colour code one of the components forming the connector, for example a body portion 220 .", "Of course, a coloured flag arrangement could also be used, as with the arrangement of FIG. 1 .", "A still further solution for providing an improved enteral feeding set is an arrangement as shown in FIG. 13 .", "In this arrangement, the enteral feeding set 302 incorporates a single connector 10 in accordance with the connector shown in FIGS. 2-10 attached to one tube 306 .", "Second tube 308 terminates in a permanent connection to a refillable fluid bag 310 .", "By providing two different fluid sources, one a rigid container containing a feeding solution and a refillable bag for receiving a flushing solution, the arrangement of FIG. 13 provides an enhanced degree of security that the correct fluid solution will be provided to the correct connection tube.", "When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the”", "and “said”", "are intended to mean that there are one or more of the elements.", "The terms “comprising”, “including”", "and “having”", "are intended to be inclusive and mean that there may be additional elements other than the listed elements.", "In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.", "As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense." ]
RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. application Ser. No. 10/032,847, filed Dec. 26, 2001, which is currently allowed and which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to insect repellent emulsion compositions that provide improved insect repellent protection to skin. The present invention also relates to a method of improving the insect repellent protection provided by a level of insect repellent active. Additionally, the repellency protection provided by an emulsion composition of the present invention also relates to a method of providing same insect repellency using less insect repellent active(s) than prior art insect repellent composition. [0004] 2. Description of the Prior Art [0005] Insect repellent compositions are available commercially in the form of emulsions with hydrophobic organic insect repellent actives in the inner discontinuous phase. Such emulsions are shown, by way of example, in U.S. Pat. No. 5,916,541. [0006] Heretofore, it has been traditionally accepted by those skilled in the art that highly stable emulsions (i.e., with small uniform droplet size) were necessary to produce insect repellent emulsions to provide adequate insect repellency. It has been observed that such stable emulsions require the use of relatively high levels of emulsifying agents, film formers and insect repellent actives. The prior art problem to be addressed is how to provide improved insect repellent protection products, preferably maximum insect repellent protection products, with a minimum amount of insect repellent active. [0007] In addition, a common problem associated with traditional insect repellent emulsions is a delay in the onset of repellency after application to the skin. This delay is related to the time required for breaking of the phases of the emulsion which are more stable in a traditional insect repellent emulsion. Consequently, consumers can experience the onset of insect exposure due to this time delay. [0008] Thus, it is desirable to have a stable insect repellent composition in emulsion form that provides enhanced insect repellent protection with a lesser amount of an insect repellent active than previously possible. SUMMARY OF THE INVENTION [0009] It is an object of the present invention to provide an insect repellent emulsion composition that provides enhanced insect repellent protection. [0010] It is another object of the present invention to provide an insect repellent emulsion composition that provides a given degree of insect repellent protection with a lesser amount of insect repellent active than previously possible. [0011] It is also another object of the present invention to provide an insect repellent emulsion composition that provides a faster onset of insect repellent action as compared to prior art insect repellent emulsion compositions. [0012] It is still another object of the present invention to provide a method of making such insect repellent emulsion compositions. [0013] It is yet another object of the present invention to provide an insect repellent composition that imparts repellency to the skin immediately or soon after application. [0014] It is yet a further object of the present invention to provide a method of protecting skin from insect pests and the damage (e.g., disease, allergic reactions) associated therewith. [0015] These and other objects and advantages of the present invention are provided in the present insect repellent composition by reducing the steric stability of an insect repellent emulsion composition, i.e., by preparing a meta-stable emulsion. The emulsion has an inner discontinuous phase and an outer continuous phase. The inner discontinuous phase and/or outer continuous phase has at least one insect repellent active therein. The inner discontinuous phase is generally dispersed within the outer continuous phase in the form of discrete droplets having a multimodal droplet size distribution. BRIEF DESCRIPTION OF THE DRAWINGS [0016] [0016]FIG. 1 illustrates a representation of a unimodal (i.e., uniform/homogeneous) droplet size distribution of a conventional (i.e., prior art) emulsion. [0017] [0017]FIG. 2 illustrates a representation of a meta-stable emulsion of the present invention having a bimodal (i.e., non-uniform/heterogeneous) droplet size distribution range. [0018] [0018]FIG. 3 illustrates a representation of a meta-stable emulsion of the present invention having a trimodal (i.e., non-uniform/heterogeneous) droplet size distribution range. [0019] [0019]FIG. 4 graphically illustrates the particle size distribution of embodiment of the present invention having a trimodal droplet size distribution range. DESCRIPTION OF THE INVENTION [0020] As stated above, the prior art teaches that, in order to obtain efficacious insect repellent protection from an insect repellent emulsion composition, the emulsion must be stable. This inherently means that the droplet size distribution throughout the emulsion is uniform/homogenous. By maintaining such uniform droplet size distribution, the droplets are less likely to come together and cause the internal and external phases of the emulsion to separate and become unstable. To maintain this uniform droplet size distribution, a relatively high degree of emulsifying agent is required, typically 10 percentage by weight or weight percent (wt %) or more based on the total weight of the inner phase components. By lowering the amount of emulsifying agent, the droplet size distribution becomes increasingly heterogeneous and causes the emulsion to become meta-stable and, ultimately, unstable if a very low amount or no emulsifying agent is used. It has, heretofore, been the common understanding that, as the stability of an insect repellent emulsion composition decreases, the insect repellent performance of such a composition similarly decreases. Contrary to the teachings of the prior art, it has now been unexpectedly and surprisingly found that insect repellent emulsion compositions with reduced steric stability (i.e., emulsions that have a heterogeneous/multi-modal droplet size distribution) provide better insect repellent performance (e.g., a longer time period of insect repellency) than prior art stable emulsions (i.e., emulsions that have uniform/unimodal/homogeneous droplet size distribution) having equal amounts of the same insect repellent active. Alternatively, insect repellent emulsions with reduced steric stability (i.e., meta-stable emulsions) can impart the same repellency as sterically stable insect repellent emulsions, but with lesser amounts of insect repellent active(s). [0021] In addition, the meta-stable emulsion compositions of the present invention break more quickly than prior art emulsions, thus allowing a quicker “release” of the insect repellent from within the emulsion, and thereby allowing a faster onset of insect repellency activity as compared to prior art insect repellent emulsion compositions. [0022] As used herein the terms “wt %” or “percentage by weight” indicates percentages based upon the total weight of the composition unless otherwise stated. [0023] As used herein, the term “repellency enhancement” includes, as compared to prior art insect repellent compositions (i.e., emulsions with homogeneous droplets), (1) increasing repellency times of the composition without increasing the concentration of insect repellent active, and (2) maintaining the same repellency times with lower concentrations of insect repellent active. The main requirement for repellency enhancement is that the emulsion of the present invention must be meta-stable, with heterogeneous droplets. [0024] In the present invention, a meta-stable emulsion can be prepared by simply reducing the amount of traditional emulsifying agent used to emulsify the inner and outer phases of the emulsion. Alternatively, the traditional emulsifying agents can be replaced altogether with certain co-solvents, as will be described herein. Similarly, an emulsion composition can be converted from stable to meta-stable by raising the concentration of the inner phase of the emulsion and/or by decreasing the external phase of the emulsion. In either case, the inner and outer phases of the emulsion will be emulsified only to a point where the emulsion is meta-stable. In other words, the emulsion will not have the uniform droplet size distribution associated with highly stable emulsions. This type of distribution is referenced to as unimodal and is shown in FIG. 1. Rather, the meta-stable emulsion of the present invention will inherently have a heterogeneous droplet size distribution (that accounts for its meta-stability). This type of distribution is referred to as multimodal (shown in FIGS. 2 and 3) because the droplets are present in the emulsion in at least two different size distribution ranges, as would be easily determinable by viewing the emulsion under a light microscope or by laser particle size analyzer. [0025] A composition that has two different droplet size ranges may also be referred to as “bimodal”. A composition with three different ranges may also be referred to as “trimodal.” A composition with four or more different ranges or in a wide range of droplet sizes may also be referred to as “polymodal.” [0026] A bimodal droplet size distribution is represented in FIG. 2. As is appreciated, there are two discrete droplet size ranges. In other words, a majority of the droplet sizes fall within the two discrete ranges as represented by the area under the curves. A non-limiting example of such a bimodal emulsion of the present invention includes a first droplet size range about 0.20 to about 1.3, more preferably 0.37 to about 0.9, microns, and a second droplet size range about 0.85 to about 4.2, more preferably about 1.4 to about 3.0 microns. [0027] A trimodal droplet size distribution is represented in FIG. 3. As is appreciated, there are three discrete droplet size ranges. In other words, a majority of the droplet sizes fall in the three discrete ranges as represented by the area under the curves. A non-limiting example of such a trimodal emulsion of the present invention has a first droplet size range from about 0.1 to about 0.8, more preferably from about 0.18 to about 0.55, microns; a second droplet size range from about 1.1 to about 4.6, more preferably about 1.8 to about 3.3, microns; and a third droplet size range from about 3 to about 16.7, more preferably from about 5.0 to about 11.9, microns. A trimodal emulsion conforming to the foregoing was made and the particle size distribution of twenty-eight particles was measured using a NIKON E800 MICROSCOPE at 400× magnification combined with IMAGE PRO PLUS SOFTWARE. The results are set forth numerically below in Table 1 and graphically in FIG. 4. TABLE 1 Distribution Range 1 Distribution Range 2 Distribution Range 3 Particle Particle Size Particle Particle Size Particle Particle Size No. Radius in Microns No. Radius in Microns No. Radius in Microns 1 0.18 9 1.37 20 5 2 0.37 10 1.8 21 5 3 0.37 11 2.2 22 6.3 4 0.37 12 2.6 23 6.3 5 0.37 13 2.6 24 6.7 6 0.37 14 2.7 25 7.24 7 0.37 15 2.7 26 7.4 8 0.55 16 2.9 27 8.1 17 3.1 28 9.1 18 3.3 19 3.3 [0028] As employed herein, “particle size radius” refers to droplet radius, which when doubled corresponds to “droplet diameter” (a.k.a. “droplet size”). Either particle size radius and/or droplet size may be determined via microscopy using image analysis software or by using a laser particle size analyzer. [0029] With respect to the present invention, the droplet size and droplet size ranges are not to be limited to a specific size or range of sizes. Rather, it is more important that the insect repellent emulsion have at least two discrete droplet size ranges. Preferably, at least about 50 wt % of the droplets fall within the discrete droplet size ranges based upon the total weight of droplets. Still more preferably, at least about 70 wt % to about 90 wt % of the droplets fall within the discrete droplet size ranges based upon the total weight of droplets. [0030] The composition may preferably take the form of an oil-in-water emulsion, a water-in-oil emulsion, a water-in-silicone emulsion, a silicone-in-water emulsion, oil-in-oil emulsion, polyol-in-silicone emulsion, a multiple emulsion, and an inverse emulsion. An oil-in-water emulsion is more preferred. [0031] The present composition has an insect repellent active in either the inner discontinuous phase or outer continuous phase of the emulsion. The insect repellent active may be organic or inorganic and water-soluble or oil-soluble. The insect repellent active is preferably one that is suitable for application to human skin, but insect repellents that are suitable for application to pets, such as cats or dogs, or livestock, active should be used in an amount sufficient to exert insect repellent activity without causing toxicity. Preferably, the insect repellent is used in an amount sufficient to provide insect repellency without human toxicity. Suitable non-limiting examples of insect repellent actives include: ethyl butylacetylaminopropionate (available under the trade name “IR3535” from Merck Co), p-menthane-3,8-diol, hydroxyethyl isobutyl piperidine carboxylate (1-piperidinecarboxylic acid) (available under the trade name “Bayer KBR 3023”), N,N diethyl-m-toluamide (also known and referred to herein as “DEET”), camphor, di N-propyl isocinchomeronate, ethyl hexanediol, essential oils such as eucalyptus oil, geranium/geraniol oil, oil of citronella, lemongrass, piperonyl butoxide, soybean oil, pyrethrum, pyrethrins, nepetalactone, and any combinations thereof. Ethyl butylacetylaminopropionate, p-menthane-3,8-diol, hydroxyethyl isobutyl piperidine carboxylate (1-piperidinecarboxylic acid), DEET and any mixture thereof are preferred insect repellent actives. It is most preferred that for the insect repellent compositions of the present the insect repellent active is or includes ethyl butylacetylaminopropionate. [0032] The amount of insect repellent active employed will depend on the level of protection desired. Insect repellent amounts may vary depending upon insect repellent active employed. The amount of insect repellent can be adjusted using standard empirical routines for optimization, as is well understood in the art. Generally, the insect repellent active is present from about 0.01 wt % about 70 wt %, more preferably from about 0.05 wt % to about 50 wt %, and most preferably from about 0.5 wt % to about 30 wt %, based on the total weight of the based on the total weight of the composition. [0033] The composition has an aqueous phase that is about 5 wt % to about 90 wt %, preferably about 10 wt % to about 80 wt %, and most preferably about 15 wt % to about 75 wt % water, based on the total weight of the composition. [0034] The present composition may include any vehicle known in the art as useful in formulating emulsions. Suitable vehicles include, but are not limited to, water; one or more vegetable oils; esters such as octyl palmitate, isopropyl myristate and isopropyl palmitate; ethers such as dicapryl ether and dimethyl isosorbide; alcohols such as ethanol and isopropanol; fatty alcohols such as cetyl alcohol, stearyl alcohol and behenyl alcohol; isoparaffins such as isooctane, isododecane and isohexadecane; silicone oils such as dimethicones and polysiloxanes; hydrocarbon oils such as mineral oil, petrolatum, isoeicosane and polyisobutene; polyols such as propylene glycol, glycerin, butylene glycol, pentylene glycol and hexylene glycol; or any combinations of the foregoing. [0035] The composition may have an emulsifier present in a limited amount effective to provide and maintain a heterogeneous, meta-stable dispersion of the inner discontinuous phase in the outer continuous phase, in which the heterogeneous droplets are in multimodal droplet size ranges. Preferably, the emulsifier will be present in an amount up to about 5 wt %, more preferably up to about 2 wt %, even more preferably up to about 1%, and most preferably up to about 0.5 wt %, based upon the total weight of the inner phase components/ingredients. [0036] Of course, the level of emulsifier used can be modified by those skilled in the art, especially when using more powerful emulsifiers such as polymerics and/or cosolvents such as polyols. The excipients of the composition can be selected to alter the required emulsifier level as well. For example, including a more polar oil, such as isopropylmyristate, instead of a nonpolar oil, such as a hydrocarbon oil, allows the amount of emulsifier required to maintain a meta-stable emulsion to be decreased. [0037] Emulsifiers that can be used in the present compositions include, but are not limited to, one or more of the following: sorbitan esters such as sorbitan monooleate and sorbitan monostearate; polyglycerol esters and glycerol esters such as glycerol monostearate and glycerol monooleate; polyoxyethylene phenols such as polyoxyethylene octyl phenol and polyoxyethylene nonyl phenol; polyoxyethylene ethers such as polyoxyethylene cetyl ether and polyoxyethylene stearyl ether; polyoxyethylene glycol esters; polyoxyethylene sorbitan esters; polyglyceryl-3-diisostearate; polyglyceryl-3-distearate; PEG-30 dipolyhydroxystearate; quaternary ammonium compounds; dimethicone copolyol; cetyl dimethicone copolyol; lecithin and its components; alkyl polyglucosides; acrylates/C 10 -C 30 alkyl acrylate copolymers; sodium stearoyl lactylate; organic phosphate salts; sodium cetearyl sulfate; or any combinations thereof, or any other component that can sufficiently reduce the surface tension between phases to allow for the formation of discrete inner phase droplets. Additional useful emulsifiers and co-emulsifiers are provided in U.S. Pat. Nos. 5,162,378 (column 4) and 5,344,665 (Table 1), which are incorporated herein by reference. [0038] The meta-stable emulsions of the present invention may be made substantially emulsifier free and still provide insect repellent enhancement. As used herein, the term “substantially emulsifier-free” means less than about 1 wt % emulsifying agent based on the total weight of the oil phase. When the meta-stable emulsion is substantially emulsifier-free, it is preferred that the emulsion includes at least one co-solvent with low surface activity (i.e., can reduce surface tension to help emulsify the emulsion phases, but without producing a fully stable emulsion). The co-solvents that can be used in the present composition include, but are not limited to, primary alcohols such as ethanol, one or more polyols, such as butylene glycol, ethylene glycol, propylene glycol and hexylene glycol; esters such as octyl palmitate, isopropyl myristate and isopropyl palmitate; ethers such as dicapryl ether and dimethyl isosorbide; ethoxylated esters; propoxylated esters; propoxylated alcohols; and alkoxylated alcohols such as polyethylene glycol. Preferably, the co-solvent is a polyethylene glycol. Suitable non-limiting examples of polyethylene glycols useful in the present invention include polyethylene glycol 1450 and polyethylene glycol 300. [0039] It is preferred that the ratio of co-solvent to insect repellent is about 0.5:1 to about 10:1, more preferably about 0.5:1 to about 5:1, and optimally at about 1:1. [0040] When preparing such an emulsifier-free composition, it is most preferable to mix the insect repellent and co-solvent together before any other ingredients are added to the insect repellent. [0041] The present invention may also incorporate emulsion stabilizers to impede the coalescence of the internal phase droplets. Such stabilizers may include, but are not limited to, polymers such as carbomer and polyurethane, cellulosics (organo-modified and otherwise), clays such as bentonite and its derivative, suspending powders such as silica, and polymethylmethacrylate. In the case of inverse emulsions, salts such as magnesium sulfate heptahydrate may also be used as emulsion stabilizers. Lowering the concentration of emulsion stabilizers in a stable cosmetic emulsion will also contribute to converting such stable emulsion to a meta-emulsion. [0042] The present composition may optionally include one or more of the following ingredients: anesthetics, anti-allergenics, antifungals, antimicrobials, anti-inflammatories, antiseptics, chelating agents, botanical extracts, colorants, depigmenting agents, emollients, exfollients, film formers, fragrances, humectants, sunscreens, lubricants, moisturizers, pharmaceutical agents, preservatives, skin protectants, skin penetration enhancers, stabilizers, surfactants, thickeners, viscosity modifiers, vitamins, or any combinations thereof. A non-limiting list of suitable sunscreens useful in the present invention is disclosed in allowed copending U.S. application Ser. No. 10/032,847, filed Dec. 26, 2001, which has been incorporated herein by reference. [0043] Suitable film formers may also be chosen by those skilled in the art. A non-limiting list of film formers includes: acrylate copolymers, acrylate/octylacrylamide copolymers, acrylate/VA copolymer, amodimethicone, AMP/acrylate copolymers, behenyl beeswax, behenyl/isostearyl, beeswax, butylated PVP, butyl ester of PVM/MA copolymers, calcium/sodium PVM/MA copolymers, dimethicone, dimethicone copolyol, dimethicone/mercaptopropyl methicone copolymer, dimethicone propylethylenediamine behenate, dimethicolnol ethylcellulose, ethylene/acrylic acid copolymer, ethylene/MA, copolymer, ethylene/VA copolymer, fluoro C2-8 alkyldimethicone, hexanediol beeswax, hydrogenated styrene/butadiene copolymer, hydroxyethyl ethylcellulose, isobutylene/MA copolymer, laurylmethicone copolyol, methyl methacrylate crosspolymer, methylacryloyl ethyl betaine/acrylates copolymer, microcrystalline wax, nitrocellulose, octadecene/MA copolymer, octadecene/maleic anhydride copolymer, octylacrylamide/acrylate/butylaminoethyl methacrylate copolymer, oxidized polyethylene, perfluoropolymethylisopropyl ether, polyacrylic acid, polyethylene, polymethyl methacrylate, polypropylene, polyquaternium-10, polyquaternium-11, polyquaternium-28, polyquaternium-4, PVM/MA decadiene crosspolymer, PVM/MA copolymer, PVP, PVP/decene copolymer, PVP/eicosene copolymer, PVP/hexadecene copolymer, PVP/MA copolymer, PVP/VA copolymer, silica, silica dimethyl silicate, sodium acrylate/vinyl alcohol copolymer, stearoxy dimethicone, stearoxytrimethylsilane, stearyl alcohol, stearylvinyl ether/MA copolymer, styrene/DVB copolymer, styrene/MA copolymer, tetramethyl tetraphenyl trisiloxane, tricontanyl trimethyl pentaphenyl trisiloxane, trimethylsiloxysilicate, VA/crotonates copolymer, VA/crotonates/vinyl proprionate copolymer, VA/butyl maleate/isobornyl acrylate copolymer, vinyl caprolactam/PVP/dimethylaminoethyl methacrylate copolymer, and vinyldimethicone. Preferred film formers include poly(vinyl pyrrolidone/1-triacontene) (available under the trade name TRICONTONYL PVP), acrylate copolymers, PVP/eicosene copolymer, PVP/hexadecene copolymer, PVP/MA copolymer, PVP/VA copolymer and polyurethanes, such as Polyurethane-1, Polyurethane-2, Polyurethane-4, Polyurethane-5 and polyesters. [0044] While the inventors do not wish to be bound by any one theory, it is believed that the meta-stable emulsions of the present invention may provide insect repellent enhancement by forming a more uniform film, thus making the addition of a film former unnecessary. However, conventional film formers may still be added to the present invention, if desired. [0045] The composition can be made into any suitable product form. Such product forms include, but are not limited to, a cream, a lotion, a gel, a mousse, a solution, and an aerosol or pump spray. In addition, the composition may be incorporated into a stick, towelette, or patch. [0046] The composition may be formulated in any manner known in the art for forming an emulsion having an insect repellent. Typically, the aqueous phase and the oil phase will be separately formulated and subsequently mixed. The main requirement for insect repellency enhancement under the present invention is that the emulsion be meta-stable. The stability of an emulsion is based principally on a physical observation test. Basically, the emulsion is put through 3 freeze/thaw cycles in which the temperatures are alternated between a low of about 40° F. to a high of about 120° F. The emulsion is then observed at 4 week and 8 week intervals. The product is deemed stable if no separation of the phases occurs, and the product maintains physical integrity, such as viscosity and pH parameters. COMPARATIVE EXAMPLES [0047] The following examples are intended to only illustrate meta-stable compositions of the present invention as compared to traditional emulsion compositions, should not be construed as limiting the scope of the present invention. Meta-Stable Emulsions Traditional (Present Emulsions Invention) (Prior Art) Ingredient wt % wt % Insect repellent (e.g., DEET, Citronella, 0.5 to 30 0.5 to 30 IR3535) Primary Emulsifier (e.g., DEA cetyl phos-   0-2.5 2.0-8.0% phate, PEG-100 stearate) CoEmulsifiers (e.g., behenyl alcohol, poly- 0 0.5-5   glyceryl stearate cetyl alcohol, choleth-24) Co-solvent (e.g., ethanol, butylene glycol) 35-55  0-10 Thickening Polymers (e.g., carbomer, acry- 0 0.1-1.0 lates copolymer) Preservative (e.g., Methylparaben, imidurea) 0.3-1   0.3-1.5 Film Former (e.g. polyurethane-1, PVP hex- 0-5 0-5 adecane copolymer) Thickening Gums (e.g., xanthan gum, 0-1   0-2.0 carageenan) Emollient oils/esters (e.g., Octyldodecanol,  0-35  0-35 isopropyl myristate) Chelating Agent (e.g., citric acid, disodium 0-1 0.1 EDTA Sunscreen (e.g., PARSOL 1789; octinoxate,  0-35  0-35 oxybenzone) Water QS QS [0048] It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be made by those skilled in the art without departing from the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.
There is provided an improved insect repellent emulsion composition. The composition has an inner discontinuous phase and an outer continuous phase. The inner discontinuous phase and/or outer continuous phase has an insect repellent active therein. The inner discontinuous phase is generally dispersed in the outer continuous phase and is in the form of discrete droplets having a multimodal droplet size distribution. There is also provided a method of protecting skin from being bitten by insects in which the above composition is applied topically to the skin. There is also provided a method of enhancing the performance of a insect repellent emulsion by forming the inner discontinuous phase as a multiplicity of droplets having a multimodal droplet size distribution. There is also provided a method of preparing an emulsifier-free insect repellent composition.
Summarize the key points of the given patent document.
[ "RELATED APPLICATIONS [0001] This application is a continuation-in-part of U.S. application Ser.", "No. 10/032,847, filed Dec. 26, 2001, which is currently allowed and which is incorporated herein by reference.", "BACKGROUND OF THE INVENTION [0002] 1.", "Field of the Invention [0003] The present invention relates to insect repellent emulsion compositions that provide improved insect repellent protection to skin.", "The present invention also relates to a method of improving the insect repellent protection provided by a level of insect repellent active.", "Additionally, the repellency protection provided by an emulsion composition of the present invention also relates to a method of providing same insect repellency using less insect repellent active(s) than prior art insect repellent composition.", "[0004] 2.", "Description of the Prior Art [0005] Insect repellent compositions are available commercially in the form of emulsions with hydrophobic organic insect repellent actives in the inner discontinuous phase.", "Such emulsions are shown, by way of example, in U.S. Pat. No. 5,916,541.", "[0006] Heretofore, it has been traditionally accepted by those skilled in the art that highly stable emulsions (i.e., with small uniform droplet size) were necessary to produce insect repellent emulsions to provide adequate insect repellency.", "It has been observed that such stable emulsions require the use of relatively high levels of emulsifying agents, film formers and insect repellent actives.", "The prior art problem to be addressed is how to provide improved insect repellent protection products, preferably maximum insect repellent protection products, with a minimum amount of insect repellent active.", "[0007] In addition, a common problem associated with traditional insect repellent emulsions is a delay in the onset of repellency after application to the skin.", "This delay is related to the time required for breaking of the phases of the emulsion which are more stable in a traditional insect repellent emulsion.", "Consequently, consumers can experience the onset of insect exposure due to this time delay.", "[0008] Thus, it is desirable to have a stable insect repellent composition in emulsion form that provides enhanced insect repellent protection with a lesser amount of an insect repellent active than previously possible.", "SUMMARY OF THE INVENTION [0009] It is an object of the present invention to provide an insect repellent emulsion composition that provides enhanced insect repellent protection.", "[0010] It is another object of the present invention to provide an insect repellent emulsion composition that provides a given degree of insect repellent protection with a lesser amount of insect repellent active than previously possible.", "[0011] It is also another object of the present invention to provide an insect repellent emulsion composition that provides a faster onset of insect repellent action as compared to prior art insect repellent emulsion compositions.", "[0012] It is still another object of the present invention to provide a method of making such insect repellent emulsion compositions.", "[0013] It is yet another object of the present invention to provide an insect repellent composition that imparts repellency to the skin immediately or soon after application.", "[0014] It is yet a further object of the present invention to provide a method of protecting skin from insect pests and the damage (e.g., disease, allergic reactions) associated therewith.", "[0015] These and other objects and advantages of the present invention are provided in the present insect repellent composition by reducing the steric stability of an insect repellent emulsion composition, i.e., by preparing a meta-stable emulsion.", "The emulsion has an inner discontinuous phase and an outer continuous phase.", "The inner discontinuous phase and/or outer continuous phase has at least one insect repellent active therein.", "The inner discontinuous phase is generally dispersed within the outer continuous phase in the form of discrete droplets having a multimodal droplet size distribution.", "BRIEF DESCRIPTION OF THE DRAWINGS [0016] [0016 ]FIG. 1 illustrates a representation of a unimodal (i.e., uniform/homogeneous) droplet size distribution of a conventional (i.e., prior art) emulsion.", "[0017] [0017 ]FIG. 2 illustrates a representation of a meta-stable emulsion of the present invention having a bimodal (i.e., non-uniform/heterogeneous) droplet size distribution range.", "[0018] [0018 ]FIG. 3 illustrates a representation of a meta-stable emulsion of the present invention having a trimodal (i.e., non-uniform/heterogeneous) droplet size distribution range.", "[0019] [0019 ]FIG. 4 graphically illustrates the particle size distribution of embodiment of the present invention having a trimodal droplet size distribution range.", "DESCRIPTION OF THE INVENTION [0020] As stated above, the prior art teaches that, in order to obtain efficacious insect repellent protection from an insect repellent emulsion composition, the emulsion must be stable.", "This inherently means that the droplet size distribution throughout the emulsion is uniform/homogenous.", "By maintaining such uniform droplet size distribution, the droplets are less likely to come together and cause the internal and external phases of the emulsion to separate and become unstable.", "To maintain this uniform droplet size distribution, a relatively high degree of emulsifying agent is required, typically 10 percentage by weight or weight percent (wt %) or more based on the total weight of the inner phase components.", "By lowering the amount of emulsifying agent, the droplet size distribution becomes increasingly heterogeneous and causes the emulsion to become meta-stable and, ultimately, unstable if a very low amount or no emulsifying agent is used.", "It has, heretofore, been the common understanding that, as the stability of an insect repellent emulsion composition decreases, the insect repellent performance of such a composition similarly decreases.", "Contrary to the teachings of the prior art, it has now been unexpectedly and surprisingly found that insect repellent emulsion compositions with reduced steric stability (i.e., emulsions that have a heterogeneous/multi-modal droplet size distribution) provide better insect repellent performance (e.g., a longer time period of insect repellency) than prior art stable emulsions (i.e., emulsions that have uniform/unimodal/homogeneous droplet size distribution) having equal amounts of the same insect repellent active.", "Alternatively, insect repellent emulsions with reduced steric stability (i.e., meta-stable emulsions) can impart the same repellency as sterically stable insect repellent emulsions, but with lesser amounts of insect repellent active(s).", "[0021] In addition, the meta-stable emulsion compositions of the present invention break more quickly than prior art emulsions, thus allowing a quicker “release”", "of the insect repellent from within the emulsion, and thereby allowing a faster onset of insect repellency activity as compared to prior art insect repellent emulsion compositions.", "[0022] As used herein the terms “wt %”", "or “percentage by weight”", "indicates percentages based upon the total weight of the composition unless otherwise stated.", "[0023] As used herein, the term “repellency enhancement”", "includes, as compared to prior art insect repellent compositions (i.e., emulsions with homogeneous droplets), (1) increasing repellency times of the composition without increasing the concentration of insect repellent active, and (2) maintaining the same repellency times with lower concentrations of insect repellent active.", "The main requirement for repellency enhancement is that the emulsion of the present invention must be meta-stable, with heterogeneous droplets.", "[0024] In the present invention, a meta-stable emulsion can be prepared by simply reducing the amount of traditional emulsifying agent used to emulsify the inner and outer phases of the emulsion.", "Alternatively, the traditional emulsifying agents can be replaced altogether with certain co-solvents, as will be described herein.", "Similarly, an emulsion composition can be converted from stable to meta-stable by raising the concentration of the inner phase of the emulsion and/or by decreasing the external phase of the emulsion.", "In either case, the inner and outer phases of the emulsion will be emulsified only to a point where the emulsion is meta-stable.", "In other words, the emulsion will not have the uniform droplet size distribution associated with highly stable emulsions.", "This type of distribution is referenced to as unimodal and is shown in FIG. 1. Rather, the meta-stable emulsion of the present invention will inherently have a heterogeneous droplet size distribution (that accounts for its meta-stability).", "This type of distribution is referred to as multimodal (shown in FIGS. 2 and 3) because the droplets are present in the emulsion in at least two different size distribution ranges, as would be easily determinable by viewing the emulsion under a light microscope or by laser particle size analyzer.", "[0025] A composition that has two different droplet size ranges may also be referred to as “bimodal.”", "A composition with three different ranges may also be referred to as “trimodal.”", "A composition with four or more different ranges or in a wide range of droplet sizes may also be referred to as “polymodal.”", "[0026] A bimodal droplet size distribution is represented in FIG. 2. As is appreciated, there are two discrete droplet size ranges.", "In other words, a majority of the droplet sizes fall within the two discrete ranges as represented by the area under the curves.", "A non-limiting example of such a bimodal emulsion of the present invention includes a first droplet size range about 0.20 to about 1.3, more preferably 0.37 to about 0.9, microns, and a second droplet size range about 0.85 to about 4.2, more preferably about 1.4 to about 3.0 microns.", "[0027] A trimodal droplet size distribution is represented in FIG. 3. As is appreciated, there are three discrete droplet size ranges.", "In other words, a majority of the droplet sizes fall in the three discrete ranges as represented by the area under the curves.", "A non-limiting example of such a trimodal emulsion of the present invention has a first droplet size range from about 0.1 to about 0.8, more preferably from about 0.18 to about 0.55, microns;", "a second droplet size range from about 1.1 to about 4.6, more preferably about 1.8 to about 3.3, microns;", "and a third droplet size range from about 3 to about 16.7, more preferably from about 5.0 to about 11.9, microns.", "A trimodal emulsion conforming to the foregoing was made and the particle size distribution of twenty-eight particles was measured using a NIKON E800 MICROSCOPE at 400× magnification combined with IMAGE PRO PLUS SOFTWARE.", "The results are set forth numerically below in Table 1 and graphically in FIG. 4. TABLE 1 Distribution Range 1 Distribution Range 2 Distribution Range 3 Particle Particle Size Particle Particle Size Particle Particle Size No. Radius in Microns No. Radius in Microns No. Radius in Microns 1 0.18 9 1.37 20 5 2 0.37 10 1.8 21 5 3 0.37 11 2.2 22 6.3 4 0.37 12 2.6 23 6.3 5 0.37 13 2.6 24 6.7 6 0.37 14 2.7 25 7.24 7 0.37 15 2.7 26 7.4 8 0.55 16 2.9 27 8.1 17 3.1 28 9.1 18 3.3 19 3.3 [0028] As employed herein, “particle size radius”", "refers to droplet radius, which when doubled corresponds to “droplet diameter”", "(a.k.a. “droplet size”).", "Either particle size radius and/or droplet size may be determined via microscopy using image analysis software or by using a laser particle size analyzer.", "[0029] With respect to the present invention, the droplet size and droplet size ranges are not to be limited to a specific size or range of sizes.", "Rather, it is more important that the insect repellent emulsion have at least two discrete droplet size ranges.", "Preferably, at least about 50 wt % of the droplets fall within the discrete droplet size ranges based upon the total weight of droplets.", "Still more preferably, at least about 70 wt % to about 90 wt % of the droplets fall within the discrete droplet size ranges based upon the total weight of droplets.", "[0030] The composition may preferably take the form of an oil-in-water emulsion, a water-in-oil emulsion, a water-in-silicone emulsion, a silicone-in-water emulsion, oil-in-oil emulsion, polyol-in-silicone emulsion, a multiple emulsion, and an inverse emulsion.", "An oil-in-water emulsion is more preferred.", "[0031] The present composition has an insect repellent active in either the inner discontinuous phase or outer continuous phase of the emulsion.", "The insect repellent active may be organic or inorganic and water-soluble or oil-soluble.", "The insect repellent active is preferably one that is suitable for application to human skin, but insect repellents that are suitable for application to pets, such as cats or dogs, or livestock, active should be used in an amount sufficient to exert insect repellent activity without causing toxicity.", "Preferably, the insect repellent is used in an amount sufficient to provide insect repellency without human toxicity.", "Suitable non-limiting examples of insect repellent actives include: ethyl butylacetylaminopropionate (available under the trade name “IR3535”", "from Merck Co), p-menthane-3,8-diol, hydroxyethyl isobutyl piperidine carboxylate (1-piperidinecarboxylic acid) (available under the trade name “Bayer KBR 3023”), N,N diethyl-m-toluamide (also known and referred to herein as “DEET”), camphor, di N-propyl isocinchomeronate, ethyl hexanediol, essential oils such as eucalyptus oil, geranium/geraniol oil, oil of citronella, lemongrass, piperonyl butoxide, soybean oil, pyrethrum, pyrethrins, nepetalactone, and any combinations thereof.", "Ethyl butylacetylaminopropionate, p-menthane-3,8-diol, hydroxyethyl isobutyl piperidine carboxylate (1-piperidinecarboxylic acid), DEET and any mixture thereof are preferred insect repellent actives.", "It is most preferred that for the insect repellent compositions of the present the insect repellent active is or includes ethyl butylacetylaminopropionate.", "[0032] The amount of insect repellent active employed will depend on the level of protection desired.", "Insect repellent amounts may vary depending upon insect repellent active employed.", "The amount of insect repellent can be adjusted using standard empirical routines for optimization, as is well understood in the art.", "Generally, the insect repellent active is present from about 0.01 wt % about 70 wt %, more preferably from about 0.05 wt % to about 50 wt %, and most preferably from about 0.5 wt % to about 30 wt %, based on the total weight of the based on the total weight of the composition.", "[0033] The composition has an aqueous phase that is about 5 wt % to about 90 wt %, preferably about 10 wt % to about 80 wt %, and most preferably about 15 wt % to about 75 wt % water, based on the total weight of the composition.", "[0034] The present composition may include any vehicle known in the art as useful in formulating emulsions.", "Suitable vehicles include, but are not limited to, water;", "one or more vegetable oils;", "esters such as octyl palmitate, isopropyl myristate and isopropyl palmitate;", "ethers such as dicapryl ether and dimethyl isosorbide;", "alcohols such as ethanol and isopropanol;", "fatty alcohols such as cetyl alcohol, stearyl alcohol and behenyl alcohol;", "isoparaffins such as isooctane, isododecane and isohexadecane;", "silicone oils such as dimethicones and polysiloxanes;", "hydrocarbon oils such as mineral oil, petrolatum, isoeicosane and polyisobutene;", "polyols such as propylene glycol, glycerin, butylene glycol, pentylene glycol and hexylene glycol;", "or any combinations of the foregoing.", "[0035] The composition may have an emulsifier present in a limited amount effective to provide and maintain a heterogeneous, meta-stable dispersion of the inner discontinuous phase in the outer continuous phase, in which the heterogeneous droplets are in multimodal droplet size ranges.", "Preferably, the emulsifier will be present in an amount up to about 5 wt %, more preferably up to about 2 wt %, even more preferably up to about 1%, and most preferably up to about 0.5 wt %, based upon the total weight of the inner phase components/ingredients.", "[0036] Of course, the level of emulsifier used can be modified by those skilled in the art, especially when using more powerful emulsifiers such as polymerics and/or cosolvents such as polyols.", "The excipients of the composition can be selected to alter the required emulsifier level as well.", "For example, including a more polar oil, such as isopropylmyristate, instead of a nonpolar oil, such as a hydrocarbon oil, allows the amount of emulsifier required to maintain a meta-stable emulsion to be decreased.", "[0037] Emulsifiers that can be used in the present compositions include, but are not limited to, one or more of the following: sorbitan esters such as sorbitan monooleate and sorbitan monostearate;", "polyglycerol esters and glycerol esters such as glycerol monostearate and glycerol monooleate;", "polyoxyethylene phenols such as polyoxyethylene octyl phenol and polyoxyethylene nonyl phenol;", "polyoxyethylene ethers such as polyoxyethylene cetyl ether and polyoxyethylene stearyl ether;", "polyoxyethylene glycol esters;", "polyoxyethylene sorbitan esters;", "polyglyceryl-3-diisostearate;", "polyglyceryl-3-distearate;", "PEG-30 dipolyhydroxystearate;", "quaternary ammonium compounds;", "dimethicone copolyol;", "cetyl dimethicone copolyol;", "lecithin and its components;", "alkyl polyglucosides;", "acrylates/C 10 -C 30 alkyl acrylate copolymers;", "sodium stearoyl lactylate;", "organic phosphate salts;", "sodium cetearyl sulfate;", "or any combinations thereof, or any other component that can sufficiently reduce the surface tension between phases to allow for the formation of discrete inner phase droplets.", "Additional useful emulsifiers and co-emulsifiers are provided in U.S. Pat. Nos. 5,162,378 (column 4) and 5,344,665 (Table 1), which are incorporated herein by reference.", "[0038] The meta-stable emulsions of the present invention may be made substantially emulsifier free and still provide insect repellent enhancement.", "As used herein, the term “substantially emulsifier-free”", "means less than about 1 wt % emulsifying agent based on the total weight of the oil phase.", "When the meta-stable emulsion is substantially emulsifier-free, it is preferred that the emulsion includes at least one co-solvent with low surface activity (i.e., can reduce surface tension to help emulsify the emulsion phases, but without producing a fully stable emulsion).", "The co-solvents that can be used in the present composition include, but are not limited to, primary alcohols such as ethanol, one or more polyols, such as butylene glycol, ethylene glycol, propylene glycol and hexylene glycol;", "esters such as octyl palmitate, isopropyl myristate and isopropyl palmitate;", "ethers such as dicapryl ether and dimethyl isosorbide;", "ethoxylated esters;", "propoxylated esters;", "propoxylated alcohols;", "and alkoxylated alcohols such as polyethylene glycol.", "Preferably, the co-solvent is a polyethylene glycol.", "Suitable non-limiting examples of polyethylene glycols useful in the present invention include polyethylene glycol 1450 and polyethylene glycol 300.", "[0039] It is preferred that the ratio of co-solvent to insect repellent is about 0.5:1 to about 10:1, more preferably about 0.5:1 to about 5:1, and optimally at about 1:1.", "[0040] When preparing such an emulsifier-free composition, it is most preferable to mix the insect repellent and co-solvent together before any other ingredients are added to the insect repellent.", "[0041] The present invention may also incorporate emulsion stabilizers to impede the coalescence of the internal phase droplets.", "Such stabilizers may include, but are not limited to, polymers such as carbomer and polyurethane, cellulosics (organo-modified and otherwise), clays such as bentonite and its derivative, suspending powders such as silica, and polymethylmethacrylate.", "In the case of inverse emulsions, salts such as magnesium sulfate heptahydrate may also be used as emulsion stabilizers.", "Lowering the concentration of emulsion stabilizers in a stable cosmetic emulsion will also contribute to converting such stable emulsion to a meta-emulsion.", "[0042] The present composition may optionally include one or more of the following ingredients: anesthetics, anti-allergenics, antifungals, antimicrobials, anti-inflammatories, antiseptics, chelating agents, botanical extracts, colorants, depigmenting agents, emollients, exfollients, film formers, fragrances, humectants, sunscreens, lubricants, moisturizers, pharmaceutical agents, preservatives, skin protectants, skin penetration enhancers, stabilizers, surfactants, thickeners, viscosity modifiers, vitamins, or any combinations thereof.", "A non-limiting list of suitable sunscreens useful in the present invention is disclosed in allowed copending U.S. application Ser.", "No. 10/032,847, filed Dec. 26, 2001, which has been incorporated herein by reference.", "[0043] Suitable film formers may also be chosen by those skilled in the art.", "A non-limiting list of film formers includes: acrylate copolymers, acrylate/octylacrylamide copolymers, acrylate/VA copolymer, amodimethicone, AMP/acrylate copolymers, behenyl beeswax, behenyl/isostearyl, beeswax, butylated PVP, butyl ester of PVM/MA copolymers, calcium/sodium PVM/MA copolymers, dimethicone, dimethicone copolyol, dimethicone/mercaptopropyl methicone copolymer, dimethicone propylethylenediamine behenate, dimethicolnol ethylcellulose, ethylene/acrylic acid copolymer, ethylene/MA, copolymer, ethylene/VA copolymer, fluoro C2-8 alkyldimethicone, hexanediol beeswax, hydrogenated styrene/butadiene copolymer, hydroxyethyl ethylcellulose, isobutylene/MA copolymer, laurylmethicone copolyol, methyl methacrylate crosspolymer, methylacryloyl ethyl betaine/acrylates copolymer, microcrystalline wax, nitrocellulose, octadecene/MA copolymer, octadecene/maleic anhydride copolymer, octylacrylamide/acrylate/butylaminoethyl methacrylate copolymer, oxidized polyethylene, perfluoropolymethylisopropyl ether, polyacrylic acid, polyethylene, polymethyl methacrylate, polypropylene, polyquaternium-10, polyquaternium-11, polyquaternium-28, polyquaternium-4, PVM/MA decadiene crosspolymer, PVM/MA copolymer, PVP, PVP/decene copolymer, PVP/eicosene copolymer, PVP/hexadecene copolymer, PVP/MA copolymer, PVP/VA copolymer, silica, silica dimethyl silicate, sodium acrylate/vinyl alcohol copolymer, stearoxy dimethicone, stearoxytrimethylsilane, stearyl alcohol, stearylvinyl ether/MA copolymer, styrene/DVB copolymer, styrene/MA copolymer, tetramethyl tetraphenyl trisiloxane, tricontanyl trimethyl pentaphenyl trisiloxane, trimethylsiloxysilicate, VA/crotonates copolymer, VA/crotonates/vinyl proprionate copolymer, VA/butyl maleate/isobornyl acrylate copolymer, vinyl caprolactam/PVP/dimethylaminoethyl methacrylate copolymer, and vinyldimethicone.", "Preferred film formers include poly(vinyl pyrrolidone/1-triacontene) (available under the trade name TRICONTONYL PVP), acrylate copolymers, PVP/eicosene copolymer, PVP/hexadecene copolymer, PVP/MA copolymer, PVP/VA copolymer and polyurethanes, such as Polyurethane-1, Polyurethane-2, Polyurethane-4, Polyurethane-5 and polyesters.", "[0044] While the inventors do not wish to be bound by any one theory, it is believed that the meta-stable emulsions of the present invention may provide insect repellent enhancement by forming a more uniform film, thus making the addition of a film former unnecessary.", "However, conventional film formers may still be added to the present invention, if desired.", "[0045] The composition can be made into any suitable product form.", "Such product forms include, but are not limited to, a cream, a lotion, a gel, a mousse, a solution, and an aerosol or pump spray.", "In addition, the composition may be incorporated into a stick, towelette, or patch.", "[0046] The composition may be formulated in any manner known in the art for forming an emulsion having an insect repellent.", "Typically, the aqueous phase and the oil phase will be separately formulated and subsequently mixed.", "The main requirement for insect repellency enhancement under the present invention is that the emulsion be meta-stable.", "The stability of an emulsion is based principally on a physical observation test.", "Basically, the emulsion is put through 3 freeze/thaw cycles in which the temperatures are alternated between a low of about 40° F. to a high of about 120° F. The emulsion is then observed at 4 week and 8 week intervals.", "The product is deemed stable if no separation of the phases occurs, and the product maintains physical integrity, such as viscosity and pH parameters.", "COMPARATIVE EXAMPLES [0047] The following examples are intended to only illustrate meta-stable compositions of the present invention as compared to traditional emulsion compositions, should not be construed as limiting the scope of the present invention.", "Meta-Stable Emulsions Traditional (Present Emulsions Invention) (Prior Art) Ingredient wt % wt % Insect repellent (e.g., DEET, Citronella, 0.5 to 30 0.5 to 30 IR3535) Primary Emulsifier (e.g., DEA cetyl phos- 0-2.5 2.0-8.0% phate, PEG-100 stearate) CoEmulsifiers (e.g., behenyl alcohol, poly- 0 0.5-5 glyceryl stearate cetyl alcohol, choleth-24) Co-solvent (e.g., ethanol, butylene glycol) 35-55 0-10 Thickening Polymers (e.g., carbomer, acry- 0 0.1-1.0 lates copolymer) Preservative (e.g., Methylparaben, imidurea) 0.3-1 0.3-1.5 Film Former (e.g. polyurethane-1, PVP hex- 0-5 0-5 adecane copolymer) Thickening Gums (e.g., xanthan gum, 0-1 0-2.0 carageenan) Emollient oils/esters (e.g., Octyldodecanol, 0-35 0-35 isopropyl myristate) Chelating Agent (e.g., citric acid, disodium 0-1 0.1 EDTA Sunscreen (e.g., PARSOL 1789;", "octinoxate, 0-35 0-35 oxybenzone) Water QS QS [0048] It should be understood that the foregoing description is only illustrative of the present invention.", "Various alternatives and modifications can be made by those skilled in the art without departing from the present invention.", "Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims." ]
CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 61/931,824 entitled PEACEKIN and filed on Jan. 27, 2014, which is specifically incorporated by reference herein for all that it discloses and teaches. TECHNICAL FIELD The invention relates generally to the field of dolls and figurines, and more particularly to a three-dimensional, customizable PeaceKin figurine. BACKGROUND Some of our oldest archeological explorations of ancient human civilizations have found dolls and figurines and associated artifacts. There are a large number of such items available today as collectibles, children's play items, decorations, etc. Nevertheless, known dolls and figurines are often overly complex, expensive to produce, prone to breakage, and can not easily and simply hold hands with one another. What is needed is a single, easy to produce base figurine that is rugged, can be easily customized based on the owner's preferences (or purchased pre-customized), has arms outstretched in a peace configuration, and yet remains able to hold hands and form a circle with other such figurines. SUMMARY One embodiment of the present invention comprises a PeaceKin having a three-dimensional head, neck, body, left arm, right arm, left sphere magnet hand, and right sphere magnet hand, as well as a substantially flat base. The spherical magnet hands allow PeaceKin to attach to one another and appear to “hold hands” without having to interlock any components. Furthermore, the PeaceKin can be easily pulled apart simply by pulling a PeaceKin away from another, and then reattached by placing the hands in proximity to each other. When two PeaceKin are facing each other with hands attached, they appear to be hugging. When three or more are placed hand-to-hand, they form a circle of PeaceKin, each holding the hands of its neighbors. The PeaceKin can each be customized to appear like a person from a given country, nationality, ethnic group, profession, sports team, holiday costume, historical figure, celebrity, religious figure, archetypal figure, any combination of the above, etc. Clothing, hats, accessories, and other paraphernalia can be attached to or worn by a given figurine to further customize each PeaceKin. And yet, the PeaceKin can be placed in a circle and hold hands to show that regardless of their differences, they can find common ground and peaceably join together. BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned and other features and objects of the present invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following descriptions of a preferred embodiment and other embodiments taken in conjunction with the accompanying drawings, wherein: FIG. 1 illustrates a front elevation perspective view of an exemplary embodiment of a PeaceKin figurine in traditional Mexican attire; FIG. 2 illustrates a front elevation view of an exemplary embodiment of a PeaceKin figurine; FIG. 3 illustrates a front, top perspective view of an exemplary embodiment of a PeaceKin figurine; FIG. 4 illustrates a rear elevation view of an exemplary embodiment of a PeaceKin figurine; FIG. 5 illustrates a left side elevation view of an exemplary embodiment of a PeaceKin figurine; FIG. 6 illustrates a right side perspective view of an exemplary embodiment of a PeaceKin figurine; FIG. 7 illustrates a top plan view of an exemplary embodiment of a PeaceKin figurine; FIG. 8 illustrates a bottom plan view of an exemplary embodiment of a PeaceKin figurine; FIG. 9 illustrates a front perspective view of a group of exemplary embodiments of PeaceKin figurines showing them holding hands in a line. DETAILED DESCRIPTION In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present disclosure. However, those skilled in the art will appreciate that embodiments may be practiced without such specific details. Furthermore, lists and/or examples are often provided and should be interpreted as exemplary only and in no way limiting embodiments to only those examples. Exemplary embodiments are described below in the accompanying Figures. The following detailed description provides a comprehensive review of the drawing Figures in order to provide a thorough understanding of, and an enabling description for, these embodiments. One having ordinary skill in the art will understand that in some cases well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. Referring now to the drawings, FIG. 1 illustrates a front elevation perspective view of an exemplary embodiment of a PeaceKin figurine 100 in traditional Mexican attire. The PeaceKin 100 in FIG. 1 has a three-dimensional, somewhat spherical head 110 with headwear 111 (here, a sombrero), and could also have hair, glasses, facial features, etc. In other embodiments, other type of add-ons are contemplated such as different hats, other headwear, various styles/colors/lengths of hair, different/less/more facial features, ears, jewelry, etc. Although not shown in FIG. 1 , the head 110 is attached to the main body 120 via a neck (see FIG. 2 , item 115 ). The PeaceKin figurine 100 in FIG. 1 is sporting custom attire 170 . In this example, the custom attire 170 reflects one type of traditional Mexican wear, including a poncho and sombrero. The custom attire 170 comprises clothing and other wearable/customizable items. In other embodiments, other types of custom attire 170 are contemplated (for additional examples, see the custom attire displayed in the Provisional Application referenced above). Extending generally outwards from the main body 120 of the PeaceKin figurine 100 are the left arm 130 and the right arm 140 . The arms 130 and 140 extend outwards and upwards, giving the PeaceKin 100 a friendly “open-arms” appearance. The arms are mostly covered by the custom attire 170 in FIG. 1 , so see FIG. 2 for more details. The arms 130 and 140 are positioned so as to provide excellent surfaces upon which to support the custom attire 170 . Furthermore, the positioning allows for the hands 137 and 147 to touch the hands of other PeaceKin figurines when placed in proximity. Because of the specific shaping and positioning, two PeaceKins appear to be hugging when placed approximately face to face (instead of the more usual “kissing” arrangement of other prior art figurines). The left sphere magnet hand 137 and right sphere magnet hand 147 allow PeaceKin figurines to attach to one another and appear to “hold hands” without having to interlock any components. Furthermore, the PeaceKin can be easily pulled apart simply by pulling each PeaceKin away from another, and then reattached by placing the hands in proximity to each other. When two PeaceKin are facing each other with hands attached, they appear to be hugging. When three or more are placed hand-to-hand, they form a line or circle of PeaceKin, each holding the hands of its neighbors. The sphere magnet hands 137 and 147 can be recessed within the ends of the arms 130 and 140 and retained therein by a lip or rim of arm material that extends beyond an equator of the sphere hands 137 and 147 . In another embodiment, the hands 137 and 147 are glued or otherwise attached (removably or permanently) to the arms 130 and 140 . At the bottom of the main body 120 is the substantially flat base 150 that supports the PeaceKin 100 and provides a stable base. Unlike many prior art figurines, the PeaceKin 100 does not rely on a pair of legs and feet, so it is inherently much more stable than those figurines that do. Instead, the PeaceKin 100 utilizes a bit of fanciful whimsy by extending the lower trunk somewhat and not utilizing any legs. This configuration allows the PeaceKin 100 to wear custom attire 170 that is normally associated with upper-body/torso only as well as attire that would normally extend all the way down a person's legs to the ground—and everything in between. The surface area of the base 150 can be greater than that of any other horizontal cross-section taken of the main body 120 . FIG. 2 illustrates a front elevation view of an exemplary embodiment of a PeaceKin figurine 100 . The portions shown in FIG. 2 include the three-dimensional, somewhat spherical head 110 , the face 112 , the neck 115 , the main body 120 , the left arm 130 , the right arm 140 , the left connector 135 , the right connector 145 , the chest 122 , the upper midsection 124 , the lower midsection 126 , and the base 150 . The face 112 comprises the front portion of the somewhat spherical head 110 . A basic PeaceKin figurine 100 does not necessarily have predetermined facial features, as shown in FIG. 2 . In another embodiment, features such as eyes, nose, mouth, chin, ears, or others can be included as part of the face 112 . In yet other embodiments, facial features can be painted on or otherwise applied to the surface of the face 112 and head 110 . The PeaceKin figurine 100 can be made of a material using any single color or mix of colors. Some commonly used colors include white, tan, brown and dark brown. PeaceKin figurines 100 can be customized by attaching hair and/or headwear. Such accessories can be attached using magnetic means or other attachment means (for example, hook and loop materials). The neck 115 serves to affix the head 110 onto the body 120 . In the PeaceKin 100 shown in FIG. 2 , the neck 115 provides a permanent attachment between the other two portions. In other embodiments, the neck 115 can provide a removable attachment to the head 110 , body 120 , or both. The arms 130 and 140 extend outwards and upwards from the main body 120 , giving the PeaceKin 100 a friendly “open-arms” appearance. The angle between the arms and the main body 120 is greater than ninety degrees and less than one hundred and thirty five degrees. In some embodiments, the arms are mostly covered by custom attire 170 (see, for example, FIG. 1 ). The arms 130 and 140 are positioned so as to provide excellent surfaces upon which to support the custom attire 170 . Furthermore, the positioning allows for the hands (not shown in FIG. 2 , see FIG. 1 , items 137 and 147 ) to touch the hands of other PeaceKin figurines when placed in proximity to one another. Although FIG. 2 appears to shown that the right arm 140 is raised to the same height as the left arm 130 ; this is not necessarily the case in other embodiments (either arm can be somewhat higher than the other). Because of the specific shaping and positioning of the arms, two PeaceKins appear to be hugging when placed approximately face to face. The left connector 135 and the right connector 145 serve to connect the left and right hands 137 and 147 (see FIG. 1 ) to their respective arms 130 and 140 . As illustrated in FIG. 2 , the left and right connectors 135 and 145 comprise sockets that are configured to hold the left and right sphere magnet hands 137 and 147 . In another embodiment, the hands comprise eight millimeter spheres. The spheres can both be magnetic, or one can be magnetic and the other can be attracted by a magnet (e.g., a steel ball bearing). In this embodiment, since only one hand is magnetic, the exact orientation of the north and south poles of that magnet are less significant, making construction of the PeaceKin less labor intensive. The left and right hands 137 and 147 can be attached to the connectors 135 and 145 with adhesives. In another embodiment, acetone is used as it has the added benefit of slightly melting the connectors when certain plastic(s) are used to construct said connectors. The hands 137 and 147 can permanently attach to the connectors, or they can removably attach to the connectors. In one embodiment, the connectors wrap around past a prime meridian of the spherical hands. In such cases, the connectors could be formed around the hands, or the hands could pop into the connectors. In other embodiments, the connectors 135 and 145 can be hook and loop material, adhesive(s), magnets, or some other form of attachment that secures the hands to the arms. A front portion of the main body 120 comprises the chest 122 , the upper midsection 124 and the lower midsection 126 . The chest 122 comprises that portion of the PeaceKin 100 between the neck 115 , the arms 130 and 140 , and the upper midsection 124 . The upper midsection 124 comprises a torso portion and is configured to transition the PeaceKin main body 120 from the chest 122 to the lower midsection 126 . The upper and lower midsections 124 and 126 form an elongated torso and can function as a torso without legs, as a torso with somewhat squat legs, or anything in between. This feature provides the PeaceKin with significant versatility such that it can be used to simulate a large variety of human heights, positions, etc. especially when used in combination with custom attire 170 . Although the lower midsection 126 flares outwards to create the wide flat base 150 , the PeaceKin 100 are able to appear to hug one another when placed face to face as the main body 120 leans slightly forward and to either the left or right. This allows the hands 137 and 147 to touch and the PeaceKin heads to appear in proximity rather than to stand back in an aloof configuration if the figurines were to stand perfectly straight (in such a case, the forward edges of the lower midsections 126 of two PeaceKin would otherwise be the only point of contact). FIG. 3 illustrates a front, top perspective view of an exemplary embodiment of a PeaceKin figurine 100 . In this view, the slight forward lean of the PeaceKin is more visible. Also, the positioning of the arms 130 and 140 is further elucidated. The head 110 , face 112 , neck 115 , chest 122 , arms 130 and 140 , connectors 135 and 145 , upper midsection 124 , lower midsection 126 , main body 120 and base 150 are all identified in this illustration. FIG. 4 illustrates a rear elevation view of an exemplary embodiment of a PeaceKin figurine 100 . The head 110 , neck 115 , arms 130 and 140 , connectors 135 and 145 , main body 120 and base 150 are illustrated in this view. Additional components shown here include the back of the head 117 , the back 123 , the upper back midsection 125 and the lower back midsection 127 . The upper and lower back midsections 125 and 127 connect to the back 123 ; these three components together comprise the rear portion of the main body 120 and correspond to the chest, upper midsection, and lower midsection from the front view (see FIG. 3 ). FIG. 5 illustrates a left side elevation view of an exemplary embodiment of a PeaceKin figurine 100 . The left side junctures between the upper midsection 124 and the upper back midsection 125 , and between the lower midsection 126 and the lower back midsection 127 are illustrated. Note also how the arm 130 flares out and upwards from the main body 120 . In the illustration of FIG. 5 , the forward lean of the PeaceKin 100 is very apparent. Note that this lean allows the PeaceKin's hands to touch another PeaceKin's hands when the two are placed in a face to face configuration. FIG. 6 illustrates a right side perspective view of an exemplary embodiment of a PeaceKin figurine 100 . The right side junctures between the upper midsection 124 and the upper back midsection 125 , and between the lower midsection 126 and the lower back midsection 127 are illustrated. Note also how the arms 130 and 140 flare out and upwards from the main body 120 . In the illustration of FIG. 6 , the forward lean of the PeaceKin 100 is also apparent. Note also the socket shape of the connector 145 . In other embodiments, the connectors are configured differently. FIG. 7 illustrates a top plan view of an exemplary embodiment of a PeaceKin figurine 100 . The placement and configuration of the head 110 is shown, as is the relationship between the face 112 and the back of the head 117 . The forward reaching orientation of the arms 130 and 140 is apparent in FIG. 7 . This orientation, combined with the forward lean of the PeaceKins allows them to appear to hold hands when placed face to face. FIG. 8 illustrates a bottom plan view of an exemplary embodiment of a PeaceKin figurine 100 . The flat nature of the base 150 is clearly illustrated in FIG. 8 . This configuration provides a solid foundation for the PeaceKin 100 so that it can stand firmly and not be easily knocked over. Additionally, the wide base provides stability such that custom attire, head-gear, and other accessories can be added to the PeaceKin without causing it to become unstable and tip over. In the embodiment shown in FIG. 8 , the flat base 150 is solid. In other embodiments, the base can be hollow, can comprise a lattice-work, or can otherwise comprise girders separated by hollow areas. In yet another embodiment, counterweight can be inserted in the base 150 (or in the interior neat to the base) to ensure the stability of the PeaceKin. This view also shows the forward reaching configuration of the arms 130 and 140 . FIG. 9 illustrates a front perspective view of a group of exemplary embodiments of PeaceKin figurines 210 , 220 , 230 , 240 and 250 showing them holding hands in a line. In the embodiment in FIG. 9 , the hands of the figurines could be magnetic (magnets and/or materials attracted thereby) so that once placed in proximity to one another, the figurines automatically grasp and hold each others' hands. Although the dress displayed in FIG. 9 is the same in general appearance for all five PeaceKin figurines, 210 , 220 , 230 , 240 and 250 , it is contemplated that the clothing and headwear could vary considerably among them. The first figurine 210 could, for example, be dressed as a Chinese girl wearing one form of traditional attire (see Provisional Patent Application 61/931,824, of which this application claims benefit, for examples). The second figurine 220 can, for example, be dressed as a Mexican boy wearing one form of traditional attire. The third figurine 230 can, for example, be dressed as an African boy wearing one form of traditional attire. The fourth figurine 240 can, for example, be dressed as a Native American girl wearing one form of traditional attire. The fifth figurine 250 can, for example, be dressed as a Middle Eastern girl wearing one form of traditional attire. Various types of traditional attire are contemplated, those discussed here are non-limiting examples. Note that the figurines in FIG. 9 can all hold hands in a line facing forward because of the configuration of the PeaceKin. The free hands of the Chinese Girl 210 and the Middle Eastern Girl 250 can be attached to one another, forming the five PeaceKin figurines into a circle facing either inwards or outwards. While particular embodiments have been described and disclosed in the present application, it is clear that any number of permutations, modifications, or embodiments may be made without departing from the spirit and the scope of this disclosure. Particular terminology used when describing certain features or aspects of the embodiments should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects with which that terminology is associated. In general, the terms used in the following claims should not be construed to be limited to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the claims encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the claimed subject matter. The above detailed description of the embodiments is not intended to be exhaustive or to limit the disclosure to the precise embodiment or form disclosed herein or to the particular fields of usage mentioned above. While specific embodiments and examples are described above for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. Also, the teachings of the embodiments provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. Any patents, applications and other references that may be listed in accompanying or subsequent filing papers, are incorporated herein by reference. Aspects of embodiments can be modified, if necessary, to employ the systems, functions, and concepts of the various references to provide yet further embodiments. In light of the above “Detailed Description,” the Inventor may make changes to the disclosure. While the detailed description outlines possible embodiments and discloses the best mode contemplated, no matter how detailed the above appears in text, embodiments may be practiced in a myriad of ways. Thus, implementation details may vary considerably while still being encompassed by the spirit of the embodiments as disclosed by the inventor. As discussed herein, specific terminology used when describing certain features or aspects should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the embodiments with which that terminology is associated. While certain aspects are presented below in certain claim forms, the inventor contemplates the various aspects in any number of claim forms. Accordingly, the inventor reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects. The above specification, examples and data provide a description of the structure and use of exemplary implementations of the described articles of manufacture and methods. It is important to note that many implementations can be made without departing from the spirit and scope of the invention.
A PeaceKin figurine has a three-dimensional head, neck, body, left and right arms, left and right spherical magnet hands, as well as a substantially flat base. The spherical magnet hands allow PeaceKin to attach to one another and appear to “hold hands” without having to interlock any components. PeaceKin can be easily pulled apart simply by pulling a PeaceKin away from another, and then reattached by placing the hands in proximity to each other. When two PeaceKin are facing each other with hands attached, they appear to be hugging because they are slightly leaning forward. When three or more are placed hand-to-hand, they form a circle of PeaceKin, each holding the hands of its neighbors. The PeaceKin can each be customized to appear like a person from a given country, nationality, ethnic group, profession, sports team, holiday costume, historical figure, celebrity, religious figure, archetypal figure, etc.
Briefly summarize the invention's components and working principles as described in the document.
[ "CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 61/931,824 entitled PEACEKIN and filed on Jan. 27, 2014, which is specifically incorporated by reference herein for all that it discloses and teaches.", "TECHNICAL FIELD The invention relates generally to the field of dolls and figurines, and more particularly to a three-dimensional, customizable PeaceKin figurine.", "BACKGROUND Some of our oldest archeological explorations of ancient human civilizations have found dolls and figurines and associated artifacts.", "There are a large number of such items available today as collectibles, children's play items, decorations, etc.", "Nevertheless, known dolls and figurines are often overly complex, expensive to produce, prone to breakage, and can not easily and simply hold hands with one another.", "What is needed is a single, easy to produce base figurine that is rugged, can be easily customized based on the owner's preferences (or purchased pre-customized), has arms outstretched in a peace configuration, and yet remains able to hold hands and form a circle with other such figurines.", "SUMMARY One embodiment of the present invention comprises a PeaceKin having a three-dimensional head, neck, body, left arm, right arm, left sphere magnet hand, and right sphere magnet hand, as well as a substantially flat base.", "The spherical magnet hands allow PeaceKin to attach to one another and appear to “hold hands”", "without having to interlock any components.", "Furthermore, the PeaceKin can be easily pulled apart simply by pulling a PeaceKin away from another, and then reattached by placing the hands in proximity to each other.", "When two PeaceKin are facing each other with hands attached, they appear to be hugging.", "When three or more are placed hand-to-hand, they form a circle of PeaceKin, each holding the hands of its neighbors.", "The PeaceKin can each be customized to appear like a person from a given country, nationality, ethnic group, profession, sports team, holiday costume, historical figure, celebrity, religious figure, archetypal figure, any combination of the above, etc.", "Clothing, hats, accessories, and other paraphernalia can be attached to or worn by a given figurine to further customize each PeaceKin.", "And yet, the PeaceKin can be placed in a circle and hold hands to show that regardless of their differences, they can find common ground and peaceably join together.", "BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned and other features and objects of the present invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following descriptions of a preferred embodiment and other embodiments taken in conjunction with the accompanying drawings, wherein: FIG. 1 illustrates a front elevation perspective view of an exemplary embodiment of a PeaceKin figurine in traditional Mexican attire;", "FIG. 2 illustrates a front elevation view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 3 illustrates a front, top perspective view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 4 illustrates a rear elevation view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 5 illustrates a left side elevation view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 6 illustrates a right side perspective view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 7 illustrates a top plan view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 8 illustrates a bottom plan view of an exemplary embodiment of a PeaceKin figurine;", "FIG. 9 illustrates a front perspective view of a group of exemplary embodiments of PeaceKin figurines showing them holding hands in a line.", "DETAILED DESCRIPTION In the following discussion, numerous specific details are set forth to provide a thorough understanding of the present disclosure.", "However, those skilled in the art will appreciate that embodiments may be practiced without such specific details.", "Furthermore, lists and/or examples are often provided and should be interpreted as exemplary only and in no way limiting embodiments to only those examples.", "Exemplary embodiments are described below in the accompanying Figures.", "The following detailed description provides a comprehensive review of the drawing Figures in order to provide a thorough understanding of, and an enabling description for, these embodiments.", "One having ordinary skill in the art will understand that in some cases well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.", "Referring now to the drawings, FIG. 1 illustrates a front elevation perspective view of an exemplary embodiment of a PeaceKin figurine 100 in traditional Mexican attire.", "The PeaceKin 100 in FIG. 1 has a three-dimensional, somewhat spherical head 110 with headwear 111 (here, a sombrero), and could also have hair, glasses, facial features, etc.", "In other embodiments, other type of add-ons are contemplated such as different hats, other headwear, various styles/colors/lengths of hair, different/less/more facial features, ears, jewelry, etc.", "Although not shown in FIG. 1 , the head 110 is attached to the main body 120 via a neck (see FIG. 2 , item 115 ).", "The PeaceKin figurine 100 in FIG. 1 is sporting custom attire 170 .", "In this example, the custom attire 170 reflects one type of traditional Mexican wear, including a poncho and sombrero.", "The custom attire 170 comprises clothing and other wearable/customizable items.", "In other embodiments, other types of custom attire 170 are contemplated (for additional examples, see the custom attire displayed in the Provisional Application referenced above).", "Extending generally outwards from the main body 120 of the PeaceKin figurine 100 are the left arm 130 and the right arm 140 .", "The arms 130 and 140 extend outwards and upwards, giving the PeaceKin 100 a friendly “open-arms”", "appearance.", "The arms are mostly covered by the custom attire 170 in FIG. 1 , so see FIG. 2 for more details.", "The arms 130 and 140 are positioned so as to provide excellent surfaces upon which to support the custom attire 170 .", "Furthermore, the positioning allows for the hands 137 and 147 to touch the hands of other PeaceKin figurines when placed in proximity.", "Because of the specific shaping and positioning, two PeaceKins appear to be hugging when placed approximately face to face (instead of the more usual “kissing”", "arrangement of other prior art figurines).", "The left sphere magnet hand 137 and right sphere magnet hand 147 allow PeaceKin figurines to attach to one another and appear to “hold hands”", "without having to interlock any components.", "Furthermore, the PeaceKin can be easily pulled apart simply by pulling each PeaceKin away from another, and then reattached by placing the hands in proximity to each other.", "When two PeaceKin are facing each other with hands attached, they appear to be hugging.", "When three or more are placed hand-to-hand, they form a line or circle of PeaceKin, each holding the hands of its neighbors.", "The sphere magnet hands 137 and 147 can be recessed within the ends of the arms 130 and 140 and retained therein by a lip or rim of arm material that extends beyond an equator of the sphere hands 137 and 147 .", "In another embodiment, the hands 137 and 147 are glued or otherwise attached (removably or permanently) to the arms 130 and 140 .", "At the bottom of the main body 120 is the substantially flat base 150 that supports the PeaceKin 100 and provides a stable base.", "Unlike many prior art figurines, the PeaceKin 100 does not rely on a pair of legs and feet, so it is inherently much more stable than those figurines that do.", "Instead, the PeaceKin 100 utilizes a bit of fanciful whimsy by extending the lower trunk somewhat and not utilizing any legs.", "This configuration allows the PeaceKin 100 to wear custom attire 170 that is normally associated with upper-body/torso only as well as attire that would normally extend all the way down a person's legs to the ground—and everything in between.", "The surface area of the base 150 can be greater than that of any other horizontal cross-section taken of the main body 120 .", "FIG. 2 illustrates a front elevation view of an exemplary embodiment of a PeaceKin figurine 100 .", "The portions shown in FIG. 2 include the three-dimensional, somewhat spherical head 110 , the face 112 , the neck 115 , the main body 120 , the left arm 130 , the right arm 140 , the left connector 135 , the right connector 145 , the chest 122 , the upper midsection 124 , the lower midsection 126 , and the base 150 .", "The face 112 comprises the front portion of the somewhat spherical head 110 .", "A basic PeaceKin figurine 100 does not necessarily have predetermined facial features, as shown in FIG. 2 .", "In another embodiment, features such as eyes, nose, mouth, chin, ears, or others can be included as part of the face 112 .", "In yet other embodiments, facial features can be painted on or otherwise applied to the surface of the face 112 and head 110 .", "The PeaceKin figurine 100 can be made of a material using any single color or mix of colors.", "Some commonly used colors include white, tan, brown and dark brown.", "PeaceKin figurines 100 can be customized by attaching hair and/or headwear.", "Such accessories can be attached using magnetic means or other attachment means (for example, hook and loop materials).", "The neck 115 serves to affix the head 110 onto the body 120 .", "In the PeaceKin 100 shown in FIG. 2 , the neck 115 provides a permanent attachment between the other two portions.", "In other embodiments, the neck 115 can provide a removable attachment to the head 110 , body 120 , or both.", "The arms 130 and 140 extend outwards and upwards from the main body 120 , giving the PeaceKin 100 a friendly “open-arms”", "appearance.", "The angle between the arms and the main body 120 is greater than ninety degrees and less than one hundred and thirty five degrees.", "In some embodiments, the arms are mostly covered by custom attire 170 (see, for example, FIG. 1 ).", "The arms 130 and 140 are positioned so as to provide excellent surfaces upon which to support the custom attire 170 .", "Furthermore, the positioning allows for the hands (not shown in FIG. 2 , see FIG. 1 , items 137 and 147 ) to touch the hands of other PeaceKin figurines when placed in proximity to one another.", "Although FIG. 2 appears to shown that the right arm 140 is raised to the same height as the left arm 130 ;", "this is not necessarily the case in other embodiments (either arm can be somewhat higher than the other).", "Because of the specific shaping and positioning of the arms, two PeaceKins appear to be hugging when placed approximately face to face.", "The left connector 135 and the right connector 145 serve to connect the left and right hands 137 and 147 (see FIG. 1 ) to their respective arms 130 and 140 .", "As illustrated in FIG. 2 , the left and right connectors 135 and 145 comprise sockets that are configured to hold the left and right sphere magnet hands 137 and 147 .", "In another embodiment, the hands comprise eight millimeter spheres.", "The spheres can both be magnetic, or one can be magnetic and the other can be attracted by a magnet (e.g., a steel ball bearing).", "In this embodiment, since only one hand is magnetic, the exact orientation of the north and south poles of that magnet are less significant, making construction of the PeaceKin less labor intensive.", "The left and right hands 137 and 147 can be attached to the connectors 135 and 145 with adhesives.", "In another embodiment, acetone is used as it has the added benefit of slightly melting the connectors when certain plastic(s) are used to construct said connectors.", "The hands 137 and 147 can permanently attach to the connectors, or they can removably attach to the connectors.", "In one embodiment, the connectors wrap around past a prime meridian of the spherical hands.", "In such cases, the connectors could be formed around the hands, or the hands could pop into the connectors.", "In other embodiments, the connectors 135 and 145 can be hook and loop material, adhesive(s), magnets, or some other form of attachment that secures the hands to the arms.", "A front portion of the main body 120 comprises the chest 122 , the upper midsection 124 and the lower midsection 126 .", "The chest 122 comprises that portion of the PeaceKin 100 between the neck 115 , the arms 130 and 140 , and the upper midsection 124 .", "The upper midsection 124 comprises a torso portion and is configured to transition the PeaceKin main body 120 from the chest 122 to the lower midsection 126 .", "The upper and lower midsections 124 and 126 form an elongated torso and can function as a torso without legs, as a torso with somewhat squat legs, or anything in between.", "This feature provides the PeaceKin with significant versatility such that it can be used to simulate a large variety of human heights, positions, etc.", "especially when used in combination with custom attire 170 .", "Although the lower midsection 126 flares outwards to create the wide flat base 150 , the PeaceKin 100 are able to appear to hug one another when placed face to face as the main body 120 leans slightly forward and to either the left or right.", "This allows the hands 137 and 147 to touch and the PeaceKin heads to appear in proximity rather than to stand back in an aloof configuration if the figurines were to stand perfectly straight (in such a case, the forward edges of the lower midsections 126 of two PeaceKin would otherwise be the only point of contact).", "FIG. 3 illustrates a front, top perspective view of an exemplary embodiment of a PeaceKin figurine 100 .", "In this view, the slight forward lean of the PeaceKin is more visible.", "Also, the positioning of the arms 130 and 140 is further elucidated.", "The head 110 , face 112 , neck 115 , chest 122 , arms 130 and 140 , connectors 135 and 145 , upper midsection 124 , lower midsection 126 , main body 120 and base 150 are all identified in this illustration.", "FIG. 4 illustrates a rear elevation view of an exemplary embodiment of a PeaceKin figurine 100 .", "The head 110 , neck 115 , arms 130 and 140 , connectors 135 and 145 , main body 120 and base 150 are illustrated in this view.", "Additional components shown here include the back of the head 117 , the back 123 , the upper back midsection 125 and the lower back midsection 127 .", "The upper and lower back midsections 125 and 127 connect to the back 123 ;", "these three components together comprise the rear portion of the main body 120 and correspond to the chest, upper midsection, and lower midsection from the front view (see FIG. 3 ).", "FIG. 5 illustrates a left side elevation view of an exemplary embodiment of a PeaceKin figurine 100 .", "The left side junctures between the upper midsection 124 and the upper back midsection 125 , and between the lower midsection 126 and the lower back midsection 127 are illustrated.", "Note also how the arm 130 flares out and upwards from the main body 120 .", "In the illustration of FIG. 5 , the forward lean of the PeaceKin 100 is very apparent.", "Note that this lean allows the PeaceKin's hands to touch another PeaceKin's hands when the two are placed in a face to face configuration.", "FIG. 6 illustrates a right side perspective view of an exemplary embodiment of a PeaceKin figurine 100 .", "The right side junctures between the upper midsection 124 and the upper back midsection 125 , and between the lower midsection 126 and the lower back midsection 127 are illustrated.", "Note also how the arms 130 and 140 flare out and upwards from the main body 120 .", "In the illustration of FIG. 6 , the forward lean of the PeaceKin 100 is also apparent.", "Note also the socket shape of the connector 145 .", "In other embodiments, the connectors are configured differently.", "FIG. 7 illustrates a top plan view of an exemplary embodiment of a PeaceKin figurine 100 .", "The placement and configuration of the head 110 is shown, as is the relationship between the face 112 and the back of the head 117 .", "The forward reaching orientation of the arms 130 and 140 is apparent in FIG. 7 .", "This orientation, combined with the forward lean of the PeaceKins allows them to appear to hold hands when placed face to face.", "FIG. 8 illustrates a bottom plan view of an exemplary embodiment of a PeaceKin figurine 100 .", "The flat nature of the base 150 is clearly illustrated in FIG. 8 .", "This configuration provides a solid foundation for the PeaceKin 100 so that it can stand firmly and not be easily knocked over.", "Additionally, the wide base provides stability such that custom attire, head-gear, and other accessories can be added to the PeaceKin without causing it to become unstable and tip over.", "In the embodiment shown in FIG. 8 , the flat base 150 is solid.", "In other embodiments, the base can be hollow, can comprise a lattice-work, or can otherwise comprise girders separated by hollow areas.", "In yet another embodiment, counterweight can be inserted in the base 150 (or in the interior neat to the base) to ensure the stability of the PeaceKin.", "This view also shows the forward reaching configuration of the arms 130 and 140 .", "FIG. 9 illustrates a front perspective view of a group of exemplary embodiments of PeaceKin figurines 210 , 220 , 230 , 240 and 250 showing them holding hands in a line.", "In the embodiment in FIG. 9 , the hands of the figurines could be magnetic (magnets and/or materials attracted thereby) so that once placed in proximity to one another, the figurines automatically grasp and hold each others'", "hands.", "Although the dress displayed in FIG. 9 is the same in general appearance for all five PeaceKin figurines, 210 , 220 , 230 , 240 and 250 , it is contemplated that the clothing and headwear could vary considerably among them.", "The first figurine 210 could, for example, be dressed as a Chinese girl wearing one form of traditional attire (see Provisional Patent Application 61/931,824, of which this application claims benefit, for examples).", "The second figurine 220 can, for example, be dressed as a Mexican boy wearing one form of traditional attire.", "The third figurine 230 can, for example, be dressed as an African boy wearing one form of traditional attire.", "The fourth figurine 240 can, for example, be dressed as a Native American girl wearing one form of traditional attire.", "The fifth figurine 250 can, for example, be dressed as a Middle Eastern girl wearing one form of traditional attire.", "Various types of traditional attire are contemplated, those discussed here are non-limiting examples.", "Note that the figurines in FIG. 9 can all hold hands in a line facing forward because of the configuration of the PeaceKin.", "The free hands of the Chinese Girl 210 and the Middle Eastern Girl 250 can be attached to one another, forming the five PeaceKin figurines into a circle facing either inwards or outwards.", "While particular embodiments have been described and disclosed in the present application, it is clear that any number of permutations, modifications, or embodiments may be made without departing from the spirit and the scope of this disclosure.", "Particular terminology used when describing certain features or aspects of the embodiments should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects with which that terminology is associated.", "In general, the terms used in the following claims should not be construed to be limited to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms.", "Accordingly, the actual scope of the claims encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the claimed subject matter.", "The above detailed description of the embodiments is not intended to be exhaustive or to limit the disclosure to the precise embodiment or form disclosed herein or to the particular fields of usage mentioned above.", "While specific embodiments and examples are described above for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize.", "Also, the teachings of the embodiments provided herein can be applied to other systems, not necessarily the system described above.", "The elements and acts of the various embodiments described above can be combined to provide further embodiments.", "Any patents, applications and other references that may be listed in accompanying or subsequent filing papers, are incorporated herein by reference.", "Aspects of embodiments can be modified, if necessary, to employ the systems, functions, and concepts of the various references to provide yet further embodiments.", "In light of the above “Detailed Description,” the Inventor may make changes to the disclosure.", "While the detailed description outlines possible embodiments and discloses the best mode contemplated, no matter how detailed the above appears in text, embodiments may be practiced in a myriad of ways.", "Thus, implementation details may vary considerably while still being encompassed by the spirit of the embodiments as disclosed by the inventor.", "As discussed herein, specific terminology used when describing certain features or aspects should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the embodiments with which that terminology is associated.", "While certain aspects are presented below in certain claim forms, the inventor contemplates the various aspects in any number of claim forms.", "Accordingly, the inventor reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects.", "The above specification, examples and data provide a description of the structure and use of exemplary implementations of the described articles of manufacture and methods.", "It is important to note that many implementations can be made without departing from the spirit and scope of the invention." ]
[0001] This application is the National Stage of International Application No. PCT/CN02/00433, filed on Jun. 21, 2002, which designated the United States and was published in Chinese, which claims the benefit of Chinese Patent Application No. 01129691.7 filed on Jun. 29, 2001, and Chines Patent Application No. 02100198.7 filed on Jan. 18, 2002. The entire teachings of the above applications are incorporated herein by reference. TECHNICAL FIELD [0002] This invention relates to new compounds for the treatment of impotence. In particular, the present invention relates to new compounds for the treatment of impotence, their preparation method and their use. BACKGROUND OF THE INVENTION [0003] Sildenafil is a selective inhibitor of phosphodiesterase whose chemical name is 1-[4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)phenylsulphonyl]-4-methylpiperazine. This compound and its preparation method as well as its use in treating cardiovascular diseases was disclosed in CN1124926A; CN1057464A disclosed the use of this compound in preparing medicine for treating erection dysfunction of male animals. CN1168376A disclosed a new method for preparing sildenafil. CN1246478A disclosed another method for preparing sildenafil. Although sidenafil is very effective on treating male erectile dysfunction, the compound has strong t toxicity and side effects. SUMMARY OF THE INVENTION [0004] The present invention provides a new selective inhibitor of phosphodiesterase, i.e. the compound as described in formula (I) and its pharmaceutically acceptable salts or its stereoisomers. Such compound has the structure of formula (I): [0005] Wherein, R 1 and R 2 may be the same or different, and independently be C 1-6 alkyl, and preferably methyl, more preferably, R 1 and R 2 are both in the cis-form of piperazine ring and are both methyl. [0006] Another object of the present invention is to provide a method for preparing the compound of formula (I). [0007] There are some new intermediates involved in the synthetic route of the present invention. Therefore, another object of the invention is to provide intermediates for preparation of compounds of formula (I). [0008] Still another object of the invention is to provide a pharmaceutical composition having the compound of formula (I) as active component. [0009] Another object of the invention is to provide the use of the compounds of formula (I) as medicine for the treatment of impotence diseases. [0010] According to the present invention, there are two substituted groups, R 1 and R 2 , and two asymmetrical carbon atoms on piperazine ring of the compounds of formula (I). R 1 and R 2 can be in cis- or trans- form of the piperazine ring. Therefore, the compounds of formula (I) are presented as various stereoisomers. These isomers alone and existing in pharmaceutically acceptable salts, are all within the scope of compounds of the present invention. [0011] Preferably, the compound of the present invention is the compounds of formula (I) wherein R 1 and R 2 are in the cis-form, and most preferably is the compound wherein R 1 and R 2 are both methyl and in cis-form, the chemical name of which is: 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo [4,3-d]pyrimidin-7-one, i.e., the compound having the structure of formula (I′): [0012] The compound of formula (I) of the present invention is not only effective for the treatment of impotence diseases, such as male erectile dysfunction, but also have such features as long-lasting medical effectiveness and lower toxicity. [0013] The following shows a method of preparing the compound of formula (I′), which is a non-limiting example of preparing compound of formula (I). [0014] The synthetic route of the compounds of formula (I′) of the present invention is illustrated as follows: [0015] The compound of formula (I′) was prepared as follow: reacting 2-ethoxy benzoic acid as raw materials with chlorosulfonic acid in the presence of thionly chloride, results in 5-chlorosulphonyl-2-ethoxy benzoic acid (compound II). Reacting compound II with cis-2,6-dimethyl piperazine (see, Zhongguo Yiyao Gongye Zazhi, 1997, vol.28(11), page 524-525), results in 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-yl-sulphonyl) benzoic acid (compound III). Nucleophilic acyl substitution of compound (III) results 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) benzoyl chloride (compound IV), which is a new compound. Reacting compound IV with compound V (see the synthesis method of the compound of formula IX in CN1246478A), in the presence of 4-dimethylaminopyridine and triethylamine, obtained 4-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)benzamido]]-1-methyl-3-n-propylpyrazole-5-carboxamide(compound VI), which is a new compound. Cyclization of compound VI in the presence of potassium t-butoxide, results 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7-one (compound I′, (formula (I′))). DETAILED DESCRIPTION OF THE INVENTION [0016] The method for preparing the compounds of formula (I′) of the present invention and their pharmaceutically acceptable salts is hereinafter described by examples. It should be understood that the examples of the preparation methods are only for the purpose of illustrating the present invention and the invention is not limited to the examples. Any modifications under the concept of the present invention to the preparation methods of the present invention fall under the scopes of the present invention. EXAMPLE 1 Preparation of 5-chlorosulphonyl-2-ethoxy Benzoic Acid (II) [0017] In a 250 ml three-neck flack, 2-ethoxy benzoic acid (50 g, 0.30 mol) was added dropwise to an ice-cooled mixtures of sulfoxide dichloride (22 ml, 0.30 mol) and chlorosulfonic acid (82.6 ml, 1.24 mol) under stirring. At the same time, the temperature of the reacting mixture was kept below 25° C. The resulting mixture was stirred at room temperature for 18 hours and then poured into ice water with stirring, and white deposit appeared. The reaction mixture was stirred for another 1 hour, filtered, washed with water, and dried in vacuum, which gave 64.4 g of crude product as white solid (II) (yield 81%). m.p. 108-110° C. The crude product was used directly in the next step without further purification. EXAMPLE 2 Preparation of 2-ethoxy-5-(cis-2,6-dimethypiperazin-4-ylsulphonyl) Benzoic Acid (III) [0018] In a 250 ml three-neck flask, 52.6 g (0.23 mol) of cis-2,6-dimethylpiperazine was added to the suspension of compound (II) (53 g, 0.20 mol) in water (170 ml) at about 10° C. with stirring, at the same time the temperature of reacting mixture was kept below 20° C. The reaction was then stirred at 10° C. for another 2 hours. The precipitate was filtered, ice-water washed, dried, and refluxed in acetone for 1 hour, and purified, gave 48 g compound (III) (yield 70%) as white crystalline, m.p. 260.5-273.0° C. (Dec.). HNMR(DMSO) δ: 7.72-7.75(2H, H-4 and H-6 on benzene ring), 7.26-7.28 (1H, H-3 on benzene ring), 4.12-4.17(2H, —CH 2 — on —OCH 2 CH 3 ), 3.5-3.53(2H, —CH 2 -on piperazine ring), 2.89-2.92(2H, —CH— on piperazine ring), 1.80-1.86(2H, —CH 2 -on piperazine ring), 1.31-1.34(3H, —CH 3 on —OCH 2 CH 3 ), 1.0-1.04(6H, two-CH 3 groups on piperazine ring). EXAMPLE 3 Preparation of 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) Benzoyl Chloride (IV) [0019] Compound (III) (34.2 g, 0.1 mol) and sulfoxide dichloride (73.0 ml, 0.5 mol) were added to a 250 ml three-neck flask and the resulting mixture was heated under reflux for 3 hours. The unreacted sulfoxide dichloride was then evaporated under reduced pressure. The ethyl acetate was added into the residue, and stirred. The precipitate was filtered, washed with ethyl acetate, dried under vacuum. The reaction gave rise to 29.4 g (74%) compound (IV) as a yellow solid. m.p., 206.0-209.5° C. HNMR(D 2 O) δ: 8.0(1H, H-6 on benzene), 7.74-7.76(1H, H-4 on benzene), 7.14-7.16(1H, H-3 on benzene), 4.08-4.11(2H, —OCH 2 —), 3.74-3.77(2H, —CH 2 -on piperazine ring), 3.32(2H, two-CH-'s-on piperazine ring), 2.19-2.25(2H, —CH 2 -on piperazine ring), 1.24-1.27(3H, —CH 3 on —OCH 2 CH 3 ), 1.09-1.10(6H, two-CH 3 groups on piperazine ring). EXAMPLE 4 Preparation of 4-[-2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) benzamide]-1-methyl-3-n-propyl pyrazole-5-carboxamide(VI) [0020] 125 ml of methylene chloride, 9.1 g (0.05 mol) of 1-methyl-4-amino-3-n-propyl pyrazole-5-formamide (V), 0.06 g (0.0005 mol) of 4-dimethylaminopyridine and 10.1 g (0.1 mol) of triethylamine were added in this order to a 500 ml three-neck flask, and then the mixture was cooled to below 10° C. with cold water. The compound (IV) (25.80 g, 0.065 mol) in methylene chloride (125 ml) solution was added dropwise into the mixture and then stirred at this temperature for 2 hours. The solvent was evaporated, then water was added to the residue. The solid was filtered and washed with ethyl acetate, gave 19.2 g compound (VI) as a grey-white solid, m.p. 197-198.5° C. (yield 76%). HNMR(CDCl 3 ) δ: 8.62(1H, H-6 on benzene ring), 7.90-7.92(1H, H-4 on benzene ring), 7.90(1H, —CO—NH—), 7.17-7.27(1H, H-3 on benzene ring), 5.73(1H, —NH— on piperazine ring), 4.37-4.41(2H, —OCH 2 CH 3 ), 4.06(3H, N—CH 3 on pyrazol ring), 3.63-3.66(2H, —CH 2 — on piperazine ring), 3.0(2H, —CH— on piperazine ring), 2.52-2.56(2H, the first CH 2 of —CH 2 CH 2 CH 3 ), 1.84-1.90(2H, —CH 2 — on piperazine ring), 1.65-1.69(2H, the second CH2 of —CH 2 CH 2 CH 3 ), 1.58-1.63(3H, —OCH 2 CH 3 ), 1.03-1.05(6H, —CH 3 on piperazine ring), 0.94-0.97(3H, —CH 2 CH 2 CH 3 ). EXAMPLE 5 Preparation of 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7-one (I′) [0021] In a 250 ml three-neck flask, 1.8 g (0.046 mol) of metallic potassium and 96 ml of dry tert-butyl alcohol were added, then to the mixture 19 g (0.0387 mol) of compound (VI) was added. The mixture was heated to reflux with stirring for 8 hours, then cooled to room temperature. 96 ml of water was added and the pH was adjusted to 7.0 by adding 0.5 mol/l of hydrochloric acid, giving precipitate and then standing for 1 hour at a temperature below 10° C. The precipitate was filtered, washed with ice-water, dried and gave 17.0 g compound (I′) (yield 93%) as white crystalline. m.p. 202.2-203.2° C. HNMR(MeOD) δ: 8.15(1H, H-6 on benzene ring), 7.90-7.93(1H, H-4 benzene ring), 7.36-7.38(1H, H-3 on benzene ring), 4.32(2H, —OCH 2 —), 4.23(3H, N—CH 3 ), 3.75-3.78(2H, —CH 2 — on piperazine ring), 3.10(2H, —CH— on piperazine ring), 2.86-2.89(2H, —CH 2 CH 2 CH 3 ), 2.04-2.10(2H, —CH 2 — on piperazine ring), 1.80-1.84(2H, —OCH 2 CH 2 CH 3 ), 1.45-1.48(3H, —OCH 2 CH 3 ), 1.14-1.17(6H, —CH 3 on piperazine ring), 0.97-1.01(3H, —CH 2 CH 2 CH 3 ). If necessary, the compound of formula (I′) may be converted into its pharmaceutically acceptable salts and compositions by conventional method. [0022] The inventors of the present invention discovered that the compounds of the present invention are very effective for treating male erectile dysfunction diseases and have low toxicity and side effects. Specific results of pharmacodynamics and toxicity test are summarized as follows: EXAMPLE 6 Pharmacodynamics Test [0023] Test 1. Penis erection test of the compound formula (I′) in rats with testis removed [0024] The result indicates that the latent period of penis erection by electric irritation (10V) can be significantly shortened (P<0.05 and P<0.01) in rats administered the compound formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively. This result is the same as another compound sildenafil (P<0.01). [0025] Test 2. Effect of the compound of formula (I′) on the sexual function in mice with testis removed [0026] Result a. The result shows that latent period which male mice catch female mice can be significantly shortened (P<0.05 and P<0.01) after administration of the compound of formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively. [0027] Result b. The result shows that the times of back-climbing on female mice by male mice (times of sexual intercourse) can be significantly increased (P<0.05 and P<0.01) when the male mice was administrated the compound formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively. EXAMPLE 7 Toxicity Test [0028] It was observed by using Bliss method that the half-lethal dosage (LD 50 ) is 901.5 mg/kg when mice were administrated the compound formula (I′) orally by gavage. The confidence limit of 95% is 772.5-1052.1 mg/kg. [0029] According to the “Chinese Journal of Clinical Pharmacology and Therapeutics”, 1999, 4(3), 237-240, the LD 50 of the compound sidenafil is 625 mg/kg when male mice were administrated orally in the single dose, and the confidence limit of 95% is 50-672 mg/kg.
The present invention relates to new compounds of formula (I) which are selective inhibitors of phosphodiesterase, their pharmaceutically acceptable salts or stereoisomers. The present invention also provides methods for preparing the compounds of formula (I) and new intermediates involved in the synthetic route of the compounds of formula (I). The compounds of formula (I) of the present invention are not only very effective for treatment of impotence diseases, such as male erectile dysfunction, but also have such features as long-lasting medical effectiveness and lower toxicity.
Condense the core contents of the given document.
[ "[0001] This application is the National Stage of International Application No. PCT/CN02/00433, filed on Jun. 21, 2002, which designated the United States and was published in Chinese, which claims the benefit of Chinese Patent Application No. 01129691.7 filed on Jun. 29, 2001, and Chines Patent Application No. 02100198.7 filed on Jan. 18, 2002.", "The entire teachings of the above applications are incorporated herein by reference.", "TECHNICAL FIELD [0002] This invention relates to new compounds for the treatment of impotence.", "In particular, the present invention relates to new compounds for the treatment of impotence, their preparation method and their use.", "BACKGROUND OF THE INVENTION [0003] Sildenafil is a selective inhibitor of phosphodiesterase whose chemical name is 1-[4-ethoxy-3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)phenylsulphonyl]-4-methylpiperazine.", "This compound and its preparation method as well as its use in treating cardiovascular diseases was disclosed in CN1124926A;", "CN1057464A disclosed the use of this compound in preparing medicine for treating erection dysfunction of male animals.", "CN1168376A disclosed a new method for preparing sildenafil.", "CN1246478A disclosed another method for preparing sildenafil.", "Although sidenafil is very effective on treating male erectile dysfunction, the compound has strong t toxicity and side effects.", "SUMMARY OF THE INVENTION [0004] The present invention provides a new selective inhibitor of phosphodiesterase, i.e. the compound as described in formula (I) and its pharmaceutically acceptable salts or its stereoisomers.", "Such compound has the structure of formula (I): [0005] Wherein, R 1 and R 2 may be the same or different, and independently be C 1-6 alkyl, and preferably methyl, more preferably, R 1 and R 2 are both in the cis-form of piperazine ring and are both methyl.", "[0006] Another object of the present invention is to provide a method for preparing the compound of formula (I).", "[0007] There are some new intermediates involved in the synthetic route of the present invention.", "Therefore, another object of the invention is to provide intermediates for preparation of compounds of formula (I).", "[0008] Still another object of the invention is to provide a pharmaceutical composition having the compound of formula (I) as active component.", "[0009] Another object of the invention is to provide the use of the compounds of formula (I) as medicine for the treatment of impotence diseases.", "[0010] According to the present invention, there are two substituted groups, R 1 and R 2 , and two asymmetrical carbon atoms on piperazine ring of the compounds of formula (I).", "R 1 and R 2 can be in cis- or trans- form of the piperazine ring.", "Therefore, the compounds of formula (I) are presented as various stereoisomers.", "These isomers alone and existing in pharmaceutically acceptable salts, are all within the scope of compounds of the present invention.", "[0011] Preferably, the compound of the present invention is the compounds of formula (I) wherein R 1 and R 2 are in the cis-form, and most preferably is the compound wherein R 1 and R 2 are both methyl and in cis-form, the chemical name of which is: 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo [4,3-d]pyrimidin-7-one, i.e., the compound having the structure of formula (I′): [0012] The compound of formula (I) of the present invention is not only effective for the treatment of impotence diseases, such as male erectile dysfunction, but also have such features as long-lasting medical effectiveness and lower toxicity.", "[0013] The following shows a method of preparing the compound of formula (I′), which is a non-limiting example of preparing compound of formula (I).", "[0014] The synthetic route of the compounds of formula (I′) of the present invention is illustrated as follows: [0015] The compound of formula (I′) was prepared as follow: reacting 2-ethoxy benzoic acid as raw materials with chlorosulfonic acid in the presence of thionly chloride, results in 5-chlorosulphonyl-2-ethoxy benzoic acid (compound II).", "Reacting compound II with cis-2,6-dimethyl piperazine (see, Zhongguo Yiyao Gongye Zazhi, 1997, vol[.", "].28(11), page 524-525), results in 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-yl-sulphonyl) benzoic acid (compound III).", "Nucleophilic acyl substitution of compound (III) results 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) benzoyl chloride (compound IV), which is a new compound.", "Reacting compound IV with compound V (see the synthesis method of the compound of formula IX in CN1246478A), in the presence of 4-dimethylaminopyridine and triethylamine, obtained 4-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)benzamido]]-1-methyl-3-n-propylpyrazole-5-carboxamide(compound VI), which is a new compound.", "Cyclization of compound VI in the presence of potassium t-butoxide, results 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7-one (compound I′, (formula (I′))).", "DETAILED DESCRIPTION OF THE INVENTION [0016] The method for preparing the compounds of formula (I′) of the present invention and their pharmaceutically acceptable salts is hereinafter described by examples.", "It should be understood that the examples of the preparation methods are only for the purpose of illustrating the present invention and the invention is not limited to the examples.", "Any modifications under the concept of the present invention to the preparation methods of the present invention fall under the scopes of the present invention.", "EXAMPLE 1 Preparation of 5-chlorosulphonyl-2-ethoxy Benzoic Acid (II) [0017] In a 250 ml three-neck flack, 2-ethoxy benzoic acid (50 g, 0.30 mol) was added dropwise to an ice-cooled mixtures of sulfoxide dichloride (22 ml, 0.30 mol) and chlorosulfonic acid (82.6 ml, 1.24 mol) under stirring.", "At the same time, the temperature of the reacting mixture was kept below 25° C. The resulting mixture was stirred at room temperature for 18 hours and then poured into ice water with stirring, and white deposit appeared.", "The reaction mixture was stirred for another 1 hour, filtered, washed with water, and dried in vacuum, which gave 64.4 g of crude product as white solid (II) (yield 81%).", "m.p. 108-110° C. The crude product was used directly in the next step without further purification.", "EXAMPLE 2 Preparation of 2-ethoxy-5-(cis-2,6-dimethypiperazin-4-ylsulphonyl) Benzoic Acid (III) [0018] In a 250 ml three-neck flask, 52.6 g (0.23 mol) of cis-2,6-dimethylpiperazine was added to the suspension of compound (II) (53 g, 0.20 mol) in water (170 ml) at about 10° C. with stirring, at the same time the temperature of reacting mixture was kept below 20° C. The reaction was then stirred at 10° C. for another 2 hours.", "The precipitate was filtered, ice-water washed, dried, and refluxed in acetone for 1 hour, and purified, gave 48 g compound (III) (yield 70%) as white crystalline, m.p. 260.5-273.0° C. (Dec.).", "HNMR(DMSO) δ: 7.72-7.75(2H, H-4 and H-6 on benzene ring), 7.26-7.28 (1H, H-3 on benzene ring), 4.12-4.17(2H, —CH 2 — on —OCH 2 CH 3 ), 3.5-3.53(2H, —CH 2 -on piperazine ring), 2.89-2.92(2H, —CH— on piperazine ring), 1.80-1.86(2H, —CH 2 -on piperazine ring), 1.31-1.34(3H, —CH 3 on —OCH 2 CH 3 ), 1.0-1.04(6H, two-CH 3 groups on piperazine ring).", "EXAMPLE 3 Preparation of 2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) Benzoyl Chloride (IV) [0019] Compound (III) (34.2 g, 0.1 mol) and sulfoxide dichloride (73.0 ml, 0.5 mol) were added to a 250 ml three-neck flask and the resulting mixture was heated under reflux for 3 hours.", "The unreacted sulfoxide dichloride was then evaporated under reduced pressure.", "The ethyl acetate was added into the residue, and stirred.", "The precipitate was filtered, washed with ethyl acetate, dried under vacuum.", "The reaction gave rise to 29.4 g (74%) compound (IV) as a yellow solid.", "m.p., 206.0-209.5° C. HNMR(D 2 O) δ: 8.0(1H, H-6 on benzene), 7.74-7.76(1H, H-4 on benzene), 7.14-7.16(1H, H-3 on benzene), 4.08-4.11(2H, —OCH 2 —), 3.74-3.77(2H, —CH 2 -on piperazine ring), 3.32(2H, two-CH-'s-on piperazine ring), 2.19-2.25(2H, —CH 2 -on piperazine ring), 1.24-1.27(3H, —CH 3 on —OCH 2 CH 3 ), 1.09-1.10(6H, two-CH 3 groups on piperazine ring).", "EXAMPLE 4 Preparation of 4-[-2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl) benzamide]-1-methyl-3-n-propyl pyrazole-5-carboxamide(VI) [0020] 125 ml of methylene chloride, 9.1 g (0.05 mol) of 1-methyl-4-amino-3-n-propyl pyrazole-5-formamide (V), 0.06 g (0.0005 mol) of 4-dimethylaminopyridine and 10.1 g (0.1 mol) of triethylamine were added in this order to a 500 ml three-neck flask, and then the mixture was cooled to below 10° C. with cold water.", "The compound (IV) (25.80 g, 0.065 mol) in methylene chloride (125 ml) solution was added dropwise into the mixture and then stirred at this temperature for 2 hours.", "The solvent was evaporated, then water was added to the residue.", "The solid was filtered and washed with ethyl acetate, gave 19.2 g compound (VI) as a grey-white solid, m.p. 197-198.5° C. (yield 76%).", "HNMR(CDCl 3 ) δ: 8.62(1H, H-6 on benzene ring), 7.90-7.92(1H, H-4 on benzene ring), 7.90(1H, —CO—NH—), 7.17-7.27(1H, H-3 on benzene ring), 5.73(1H, —NH— on piperazine ring), 4.37-4.41(2H, —OCH 2 CH 3 ), 4.06(3H, N—CH 3 on pyrazol ring), 3.63-3.66(2H, —CH 2 — on piperazine ring), 3.0(2H, —CH— on piperazine ring), 2.52-2.56(2H, the first CH 2 of —CH 2 CH 2 CH 3 ), 1.84-1.90(2H, —CH 2 — on piperazine ring), 1.65-1.69(2H, the second CH2 of —CH 2 CH 2 CH 3 ), 1.58-1.63(3H, —OCH 2 CH 3 ), 1.03-1.05(6H, —CH 3 on piperazine ring), 0.94-0.97(3H, —CH 2 CH 2 CH 3 ).", "EXAMPLE 5 Preparation of 5-[[2-ethoxy-5-(cis-2,6-dimethylpiperazin-4-ylsulphonyl)phenyl]]-1-methyl-3-n-propyl-7,6-dihydro-1H-pyrazolo[4,3-d]pyrimidin-7-one (I′) [0021] In a 250 ml three-neck flask, 1.8 g (0.046 mol) of metallic potassium and 96 ml of dry tert-butyl alcohol were added, then to the mixture 19 g (0.0387 mol) of compound (VI) was added.", "The mixture was heated to reflux with stirring for 8 hours, then cooled to room temperature.", "96 ml of water was added and the pH was adjusted to 7.0 by adding 0.5 mol/l of hydrochloric acid, giving precipitate and then standing for 1 hour at a temperature below 10° C. The precipitate was filtered, washed with ice-water, dried and gave 17.0 g compound (I′) (yield 93%) as white crystalline.", "m.p. 202.2-203.2° C. HNMR(MeOD) δ: 8.15(1H, H-6 on benzene ring), 7.90-7.93(1H, H-4 benzene ring), 7.36-7.38(1H, H-3 on benzene ring), 4.32(2H, —OCH 2 —), 4.23(3H, N—CH 3 ), 3.75-3.78(2H, —CH 2 — on piperazine ring), 3.10(2H, —CH— on piperazine ring), 2.86-2.89(2H, —CH 2 CH 2 CH 3 ), 2.04-2.10(2H, —CH 2 — on piperazine ring), 1.80-1.84(2H, —OCH 2 CH 2 CH 3 ), 1.45-1.48(3H, —OCH 2 CH 3 ), 1.14-1.17(6H, —CH 3 on piperazine ring), 0.97-1.01(3H, —CH 2 CH 2 CH 3 ).", "If necessary, the compound of formula (I′) may be converted into its pharmaceutically acceptable salts and compositions by conventional method.", "[0022] The inventors of the present invention discovered that the compounds of the present invention are very effective for treating male erectile dysfunction diseases and have low toxicity and side effects.", "Specific results of pharmacodynamics and toxicity test are summarized as follows: EXAMPLE 6 Pharmacodynamics Test [0023] Test 1.", "Penis erection test of the compound formula (I′) in rats with testis removed [0024] The result indicates that the latent period of penis erection by electric irritation (10V) can be significantly shortened (P<0.05 and P<0.01) in rats administered the compound formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively.", "This result is the same as another compound sildenafil (P<0.01).", "[0025] Test 2.", "Effect of the compound of formula (I′) on the sexual function in mice with testis removed [0026] Result a. The result shows that latent period which male mice catch female mice can be significantly shortened (P<0.05 and P<0.01) after administration of the compound of formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively.", "[0027] Result b. The result shows that the times of back-climbing on female mice by male mice (times of sexual intercourse) can be significantly increased (P<0.05 and P<0.01) when the male mice was administrated the compound formula (I′) at the dosage of 24 mg/kg and 12 mg/kg, respectively.", "EXAMPLE 7 Toxicity Test [0028] It was observed by using Bliss method that the half-lethal dosage (LD 50 ) is 901.5 mg/kg when mice were administrated the compound formula (I′) orally by gavage.", "The confidence limit of 95% is 772.5-1052.1 mg/kg.", "[0029] According to the “Chinese Journal of Clinical Pharmacology and Therapeutics”, 1999, 4(3), 237-240, the LD 50 of the compound sidenafil is 625 mg/kg when male mice were administrated orally in the single dose, and the confidence limit of 95% is 50-672 mg/kg." ]
This is a divisional of application Ser. No. 09/438,545, filed Nov. 12, 1999, now allowed. FIELD OF THE INVENTION The present invention relates to a printer, and particularly, but not exclusively to a portable printer which can print on a variety of surfaces. BACKGROUND TO THE INVENTION In the state of the art, a number of printers capable of “direct” printing is known. Direct printing in the context of the present invention means that the printer is placed on the image receiving medium, usually manually, and the printing means of the printer or the entire printer then scans over the image receiving medium in the printing operation. Thus, the medium is not fed through the printer—as in most office printers—but the printer moves over the medium. Such a printer is known from EP 564297-A. The printer has an ink jet print head which scans in two orthogonal directions over the image receiving medium, onto which the printer is placed manually. The printer is connected to a computer and capable, e.g. of printing addresses onto envelopes, but can also be used separately from the computer for printing data downloaded from the computer to the printer. Another ink jet printer to be placed on a printing medium is disclosed in U.S. Pat. No. 5,634,730. This printer is provided with a keyboard for data inputting, but can also print images downloaded from a computer. The print head scans over the image receiving medium along a special path, e.g. helically or like a pendulum. DE 3142937-A refers to a so-called hand stamp which is placed manually on the image receiving medium. It can print data downloaded from an accounting machine, or images consisting of user-selected fixed phrases. The hand stamp has a thermal print head and an ink ribbon for printing. The direct printers known in the prior art are thus capable of printing an image onto an image receiving medium, and make use of a scanning print head. JP-6286227 discloses an electronic stamping apparatus which includes a pressure detection means that detects whether the pressure applied to an object is in a prescribed range, and a control means that controls scanning of a thermal transfer head based on the detection by the pressure detection means. This requires contact between the print head and the surface to be printed, in contrast to the printers described herein where the print head is spaced from the image receiving medium. SUMMARY OF THE INVENTION It is an aim of the present invention to improve the quality of images which are printed by the so-called direct printers. According to various aspects of the invention, this can be done in a number of different ways. According to one aspect of the invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium at a printing location and defining an area over which printing is effected; a printing mechanism operable to effect printing over said area with the housing at said printing location; means for detecting relative movement between the image receiving medium and the housing during printing; and a controller for inhibiting printing when such relative movement is detected. The means for detecting relative movement may be for example a scanner head, mouse ball etc. Thus, any relative motion detected during the print cycle may be used to interrupt or terminate the print cycle. According to another aspect of the invention there is provided a printer comprising: a housing arranged to be manually position on an image receiving medium at a printing location and defining an area over which printing is effected; a printing mechanism operable to effect printing over said area with the housing at said printing location; means for detecting orientation of the housing with respect to the image receiving medium during printing; and a controller for inhibiting printing when an orientation other than a correct predetermined orientation is detected. The means for detecting orientation of the housing can be for example a tilt sensor. Thus, the tilt sensor enables the print cycle to be inhibited unless the printer is positioned in the correct orientation. According to a further aspect of the invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium and defining an area over which printing is effected; a print head having a plurality of ink jet nozzles and mounted in said housing for travel within said housing relative to the image receiving medium to effect printing, said print head having an extent of travel which extends in a region outside the printing area; a controller for actuating said ink jet nozzles in said region as a maintenance procedure; and a set of absorbent strips arranged in said region for receiving ink ejected from the jet nozzles during the maintenance procedure. By using the unprintable area for interim “spitting”,—the print function can be maintained by preventing individual jets from blocking. The absorbent strips which are used to catch any drops of ink spat out may be replaceable. According to a further aspect of the present invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium at a printing location and defining an area over which printing is effected; a print head mounted in said housing for travel within said housing relative to the image receiving medium to effect printing; a motor for driving said print head under the control of a drive signal; and a controller for generating the drive signal for the motor wherein the controller includes fault condition detecting means which are operable to detect when the drive signal exceeds a predetermined limit and to inhibit printing in said fault condition. In the described embodiment, the drive signal is an electric current which is supplied to the motor for causing movement of the print head. For an X-Y movement, there are two motors, one for moving the print head along an axis in an X direction and the other for moving the axis itself in a Y direction. Under normal printing loads, the drive current to the X-Y drive motors will follow a repeatable profile. Should the printing mechanism jam or encounter a higher resistance than normal, for example when printing on an uneven surface, the drive motor current will rise. By setting the boundaries that encompass the normal operating currents, current outside these boundaries may be detected as a fault condition and used to inhibit printing. In another aspect, the invention provides a printing system comprising: a printing unit; a base station configured to receive the printing unit when not in use and having means for detecting return of the printing unit to the base station; and wherein a maintenance sequence for the printing unit is initiated on detection of return of the printing unit to the base station. In another aspect the invention provides a printer comprising: a housing arranged to be manually positioned on an image receiving medium and having an opening defining an area over which printing is effected; a print head having a plurality of ink jet nozzles and mounted in said housing for travel within said housing relative to the image receiving medium to effect printing, said print head travelling at least within said opening and over said area to effect printing; and a cover removably attachable to said housing to close said opening when said printer is not in use. For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a printer, a base station and a computer; FIG. 2 shows the print mechanism of the printer; FIG. 3 a shows the underside of the printer with absorbent strips; FIG. 3 b is a perspective view illustrating the use of absorbent strips; FIG. 3 c is another perspective view illustrating the use of absorbent strips; FIG. 4 a is a view of a mechanism for fixing the print head in the printer; FIGS. 4 b and 4 c illustrate how the arrangement of FIG. 4 a functions as a detector; FIG. 4 d illustrates an embodiment of a motion detector; FIG. 5 illustrates the operation mode of the printhead; FIGS. 6 a and 6 b illustrate a tilt sensor; and FIG. 7 illustrates the printer with a dust cover. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a printing system consisting of a computer 10 , a computer controlled display 12 , which is in the described embodiment of the invention a CRT, a keyboard 14 linked to the computer 10 by means of a cable 16 , another cable 18 , connecting the computer 10 with a base station 20 , which is connected to a printer 24 by means of a cable 22 . Thus, the printer 24 is linked to the computer 10 via the cables 18 , 22 and the base station 20 . As known in the prior art, the computer 10 comprises a processor on which a software is running, comprising an operating system, a printer driver to enable printing with the printer 24 from the operating system, and a software application by which data can be created, selected and formatted on the PC, for defining image patterns to be printed by the printer 24 . The software application can be activated in a number of ways: selected by the user at start-up or from the desktop: the user places the software application in the start-up directory or creates an icon on the desktop; from within another application: the user invokes the software application from a button (displayed on the display 12 ) in the toolbar of another software application; from the handheld printer 24 itself: if the application is not running, the user presses a print button 34 on the handheld printer 24 , which will automatically invoke the software application in the first instance. Another possibility to activate the software application on the computer 10 for controlling the printer 24 is to lift the printer 24 off the base station 20 . A switch 32 is provided in the base station 24 sensing the presence or absence of the printer 24 by means of a pin 30 . When the printer 24 is placed upon the base station, the pin 30 is depressed, and the switch 32 is open. In the case that the printer 24 is removed from the base station 20 , the pin 30 which is biased in the vertical direction moves upwardly and the switch 32 opens. The switch is connected via some electronic circuits to the computer 18 and activates the software application for printing. The base station 20 is connected to the computer 10 by means of the cable 18 , which can be a parallel or a USB cable. Electric power is supplied to the base station 20 by a separate mains transformer, but could also be supplied from the computer via the cable 18 , preferably when the cable 18 is a USB cable. The cable 18 can be hard wired to the base station 20 , or connected to a socket of the base station, which is preferably provided at the rear thereof. When the printer 24 is not in use, the handheld printer will be placed in the base station 20 . The base station 20 will ensure that the ink jet print head of the printer 24 is protected when not in use by a capping device that will be automatically triggered whenever the printer is inserted into the base station 20 . The base station 20 will also cause the print head of the printer 24 to eject ink into a reservoir and mechanically clear the surface of the print head. These measures are necessary to maintain optimum print quality. The umbilical cable 22 connects the base station 20 to the hand held printer 24 , providing both power and data. A LED on the printer will indicate that power is on. The printer 24 is removed from the base station 24 and positioned on the surface to be printed. The length of the cable 22 limits the distance of travel from the base station. In another embodiment of the invention, the printer is arranged to be disconnected from the base station by unplugging the umbilical cable 22 and moved to another location where printing of the contents of on-board memory, i.e. downloaded image data, can be effected. The user will employ scroll buttons on the printer to select the required print data, which appear in a small LCD. Once a selection has been made, pressing the print button 34 will activate printing. Having selected the data to print using the software application (or the scroll buttons on the printer), the user will activate printing from the print button 34 on the hand held printer 24 itself. Print alignment is achieved visually through a transparent window 36 in the printer casing. This window 36 can also be opened for inserting an ink cartridge into the printer 24 before use. The cartridge is then clamped in a carriage of the printer 24 . The window 36 must be closed before printing. The user can choose from a range of coloured and special inks. Changing a cartridge is achieved by lifting a retaining lever and extracting the cartridge in use and replacing this with a new or different colour cartridge in the way described above. If the removed cartridge still contains ink and is to be reused it must be capped to avoid the ink drying out. Alternatively a Think jet type head from Hewlett Packard may be used which utilises a different type of ink which does not dry out in the print head. The printer 24 contains a print mechanism with the ink jet print head having a number of print nozzles, and an ink supply. The print head is moved by means of motor driven scanning means within the housing in two (generally orthogonal) directions such that a rectangular area can be imprinted through an aperture of the printer 24 at the bottom of its housing. Thus, the printer 24 is placed manually on an image receiving medium and—when the print button 34 is depressed—the print head scans over the medium and imprints it by spitting ink droplets onto it. FIG. 1 shows the printer 24 , base station 20 and computer 10 linked by cables. In an embodiment, it is possible to replace one or all of these links by a wireless link such as a low power RF link or an infra-red link. FIG. 1 also shows the presence of a “Smart Card” reader 28 in the base station 20 . Smart cards 26 , i.e. memory cards, may be used for storing data or images or as a substitute for additional RAM in the base station. Spare cards may be stored within the base station where a storage compartment is provided (not shown). In the case that the printer 24 is powered only by batteries, rather than having the cable 22 transmitting power from the base station 20 , the amount of charge remaining in the batteries may be monitored an displayed on a display of the printer 24 , and/or on the display 12 of the computer 10 . If rechargeable batteries are used, the battery monitoring system could also be used to control the charge/discharge cycle of the battery pack to maximise battery life. This could also enable rapid recharging of the batteries. Such a battery management system could also indicate that there was sufficient energy remaining in the battery pack to complete the current task. The print mechanism of the printer will now be described with reference to FIG. 2 . The printer 24 has a housing 200 , the underside of which can be abutted against the surface of the image receiving medium to be printed. A print face 11 is defined by the scanning range of an ink jet print head cartridge 126 which can be replaced using the cartridge release mechanism described above. The ink jet print head cartridge 126 is mounted for movement along a write axis 128 by virtue of cooperating lead screw 130 and nut 132 . The movement is controlled by a motor 134 (stepper or DC depending on the nature of the print head). The position of the write axis 128 can be altered by an indexing axis lead screw and bush 136 controlled by a further stepper motor 138 . Reference numeral 140 designates a stability bar which extends parallel to the write axis 128 , the ink jet print head cartridge 126 being mounted between the write axis 128 and the stability bar 140 . Reference numeral 142 designates an indexing axis stability bar and bush. If a Think jet print head is used, a DC motor and encoder may be used in place of a stepper motor. The printer also includes an electronic controller 100 having a microprocessor for controlling movement of the motor 34 and generating signals for controlling the print head and having a buffer memory for storing data. The microprocessor is capable of converting data from a computer to which the device is connected into a format suitable for driving the print head. The buffer memory can store information in a variety of formats to enable the printer to work with a variety of computer equipment. In FIG. 2, the line 120 defines the extent of travel of the print cartridge 126 in the X and Y directions. Referring now to FIG. 3, a print area 122 which is denoted inside the dotted lines 122 a is defined which does not use up the full extent of travel of the print head cartridge 126 . Additional travel is required so that the print head can be accelerated/decelerated to and from optimum print speed and hence firing frequency. If print occurs during acceleration/deceleration, it is necessary to deviate from the print head specified firing frequency and print quality will deteriorate. FIG. 3 a shows the underside of the printing apparatus with all of the drive features removed for the sake of clarity. Thus, it discloses only the travel area 120 , the print area 122 and absorbent strips 124 . These absorbent strips are placed along the edges of the area of travel of the print head and outside the printing area 122 . These absorbent strips allow maintenance of the print head cartridge 126 by allowing ink to be ejected outside the print zone in order to purge the print nozzles and reduce the risk of clogged nozzles. Thus, the unprinted region between lines 120 and 122 a is used for interim spitting to maintain the print cartridge function by preventing individual jets from blocking. The strips of absorbent material may be replaced and are attached to the base of the printer and used to collect any drops of ink spat out to help maintain the print cartridge print quality. The strips should extend beyond the print head travel area to increase their effective ink capacity. Ink will wick out from the actual “spit” position to the extreme edges of the strips. FIGS. 3 b and 3 c illustrate the concept in more detail, with extraneous components removed for the sake of clarity. That is, in FIG. 3 c , reference numeral 124 denotes a rectangular absorbent strip. Reference numeral 230 denotes a thin fixed guide mounted on the bottom face of the printer 24 in the centre of which a rectangular aperture is provided (see also FIG. 3 b ). The print face is defined within the rectangular aperture. The guide is shown on the substrate in FIG. 3 b to illustrate its function to allow the print cartridge 126 to pass over it to print to the edge of the print area defined by it. FIG. 4 a illustrates how a print cartridge 72 is mounted in the printer 24 . A metal (or plastics) base plate 60 is mounted for scanning motion along the direction indicated by arrow A. The necessary mechanism for scanning in this direction is not shown in FIG. 4 a , for the sake of clarity. On the base plate 60 , a first guide rail 62 is provided, and a second guide rail 64 . Both guide rails 62 , 64 extend in a direction which is orthogonal to the direction of movement of the plate 60 . Additionally, two wheels 78 are provided, around which a drive belt 66 is located. The drive belt 66 is preferably toothed and extends parallel to the guide rails 62 , 64 . Further, a pin 70 is provided on a pin holder 68 , the latter being fixed to the drive belt 66 . The print cartridge 72 provided with an ink supply and nozzles for depositing the ink onto an image receiving medium is provided with three snap-on bearings 80 , 82 , 84 . The bearings 80 and 82 are arranged to be snapped (or clipped) into the first guide rail 62 , and the bearing 84 is arranged to be snapped into the second guide rail 64 . Thus, the cartridge 72 can be slidably fixed to the guide rails 62 , 64 and travel along the longitudinal axis of the guide rails. The pin 70 engages in a hole 86 of the cartridge, such that a driving connection between the drive belt 66 and the cartridge 72 is established. An electrical connector is incorporated in the pin 70 so that the drive signals can be transmitted to the print head. A dynamic cable (not shown) links the electrical connector with the drive circuitry elsewhere in the product. When the belt is driven (by means of a corresponding motor, not shown in FIG. 4 a for the sake of clarity, but it could drive the belt 66 through the rectangular window in the base plate 60 ), the cartridge 72 travels along the guide rails 62 , 64 . In order to control the print head of the cartridge 72 , the printer's control electronic requires information on the position of the print head. Thus, a pinwheel 74 engaging the printed medium is provided on the cartridge. The pinwheel 74 rotates when the cartridge 72 moves along the guide rails 62 , 64 and its rotation is detected by means of a motion detector 76 . The pinwheel 74 allows for the detection of the flatness of a substrate to help maintain print quality. As the pinwheel rotates, its rotation is detected by the motion detector 76 and a signal is produced. The pinwheel only rotates when the print cartridge is the correct distance from the substrate and the wheel is in contact with the substrate. At the end of each print pass, when the print cartridge is indexed forward ready to print the next pass, the pinwheel is held clear of the substrate to prevent damage. Alternatively a castor or track ball which can rotate about two orthogonal axes could be used. If the pinwheel loses contact with the substrate during the normal printing pass, the wheel no longer rotates, the signal is lost and the print cycle is inhibited. The base plate 60 and the pins on which the wheels 78 are mounted, and the guide rails 62 , 64 are unitary. Thus, the base plate 60 is produced as a unitary unit, e.g. by die casting, in order to simplify constructions and minimise component cost. It should be noted that a movement along the direction indicated by the arrow A is not necessary when the cartridge 72 contains a print head having a width sufficient to print the entire image receiving medium in one scan. FIGS. 4 b and 4 c illustrate in more detail how the arrangement of FIG. 4 a operates to implement “no contact, no printing”. In FIGS. 4 b and 4 c , the first position of the print cartridge 72 is shown outlined in a full black line and denoted position A. The second position is denoted by a dotted line and is denoted position B. The second position is shown to be over a small dip in the substrate such that the pinwheel 74 loses contact. FIG. 4 b illustrates how, in moving from position A to position B, the pinwheel 74 loses contact with the substrate over the small dip. FIG. 4 c illustrates the detector 76 in more detail. Each detector comprises a light emitter 76 a and a light sensor 76 b . In position A, light from the emitter 76 a reaches the sensor 76 b . In position B, it can be seen that the small dip in the substrate causes light from the emitter 76 a to be reflected at an angle such that it does not reach the light sensor 76 b . Thus, a fault condition is detected. Thus, although the primary function of the pinwheel 74 and motion detector 76 is to monitor surface contact, it can also be used to detect movement of the printer relative to the substrate. In particular this may be achieved by comparing the actual signal received from the detector with a reference signal, the reference being generated by a calibration operation where the printer is held in contact with a substrate and not allowed to move while the printer prints a test pattern. An alternative arrangement could be to mount at least two separate pinwheel sensors orthogonally with respect to one another within the body of the printer. When the printer is in contact with the substrate and in the printing position, no movement signal will be generated by these sensors. If relative movement occurs between the printer and the substrate, a signal will be generated by one or both of the sensors and a fault condition flagged. A further movement detection technique could be to use a two dimensional detection system as illustrated in FIG. 4 d . A heavy ball 210 has a high friction outer surface against which rests two orthogonal shafts 212 , 214 . Attached to these shafts are respective rotary encoders 216 , 218 . When the printer contacts the substrate, the ball rests on the substrate and any movement of the printer relative to the substrate is converted to a movement of one or other or both of the encoders. FIG. 5 illustrates how scanning is performed over the image receiving medium. Most ink jet printers known in the prior art accelerate the print cartridge from rest to normal printing speed prior to firing the ink droplets. This simplifies the control of ink droplet spacing and allows the print head to be fired at a optimum frequency, but the additional space required to accelerate the print cartridge increases the overall size of the product. The printer described here is hand held and thus requires that the overall dimensions are minimised. The control system of the print cartridge 72 thus provides the ability to print as the print cartridge assembly is accelerating—during printing of the left margin 90 of the image receiving medium 48 ′—and decelerating—during print of the right margin 90 ′ of the image receiving medium 48 ′—at the start and finish of each sweep of the mechanism thus enabling the product dimensions to be minimized for a given size of the print area on the image receiving medium. The drive signals issued by the controller 100 to the DC motors 134 and 136 thus follow a repeatable profile under normal printing loads. Should the mechanism jam or encounter a higher resistance than normal, the drive motor current requirement for the motors will rise. If boundaries are set that encompass the normal operating currents, then currents outside this area may be detected as a fault condition and the appropriate action taken to stop printing. Thus, reverting to FIG. 2, the DC motor 134 is controlled by drive signal 154 and the DC motor 138 is controlled by drive signal 158 . Feedback signals 164 and 168 respectively return the back EMF conditions of the motor to the controller 100 . This allows the controller to monitor the profile boundary and to detect the fault condition. It is important when the printer 24 has been aligned at a print location and is executing printing that the printer is correctly oriented while printing is being effected. That is, it is important that the printer 24 is placed squarely at the print location and is not tilted at an angle. That is, the print head 126 should desirably move in a plane parallel to the plane on which printing is to be effected. The tilt sensor of FIGS. 6 a and 6 b allows this to be achieved. The tilt sensor comprises a housing 200 which defines therein a part-spherical or “bowl-shaped” surface 202 . As can be seen, FIG. 6 b is a section taken along lines VI—VI of FIG. 6 a , but with the tilt sensor in a different position in each figure. At the lower-most point of the part-spherical surface 202 , a microswitch 204 is located. A ball 206 rolls freely on the part-spherical surface 202 and can roll in any radial direction. In FIG. 6 a , the tilt sensor is shown in its properly oriented position, with the ball 206 located over the microswitch 204 . This state is detected as a safe state, and printing is allowed to continue while the ball remains in that position. If however the unit moves, the ball will roll away from the centralised position over the microswitch, allowing the microswitch 204 to detect the absence of the ball 206 , as illustrated for example in FIG. 6 b . This is detected as a fault condition, and printing is inhibited. This allows movement of the printer during printing to be detected and printing to be inhibited accordingly. It will also be apparent that if the printer is placed at the printing location in anything other than the correct orientation, the ball 206 will not be over the microswitch 204 and thus the fault condition will immediately be detected even prior to printing. The printer must be properly aligned vertically before printing can be effected. FIG. 7 illustrates the printer 24 with a sealing lid or dust cover 300 attachable to the printer 24 to close the print face 11 in the base of the printer. In addition, a window 302 is hinged to the housing of the printer 24 whereby the window can be releasably hinged or fixed to the printer 24 . In accordance with one embodiment, when the printer 24 is returned to the base station 20 , the printer 24 automatically cycles through a service routine to maintain the print cartridge performance. This sequence is triggered by a switch 304 (FIG. 1) in the base station which senses return of the printer to the base station 20 . The service routine can be determined by the supplier of the ink jet cartridge such as to maintain the print cartridge performance.
A portable printer which can print on a variety of surfaces is disclosed. The printer has a number of failsafe features which improve its operation and the quality of print. In particular, printing is inhibited in a certain number of situations. Alternatively or additionally, a maintenance sequence can be implemented when the printing unit is removed from a base location. A set of absorbent strips additionally or alternatively allow for the ink jet nozzles to be discharged within the print area.
Briefly describe the main idea outlined in the provided context.
[ "This is a divisional of application Ser.", "No. 09/438,545, filed Nov. 12, 1999, now allowed.", "FIELD OF THE INVENTION The present invention relates to a printer, and particularly, but not exclusively to a portable printer which can print on a variety of surfaces.", "BACKGROUND TO THE INVENTION In the state of the art, a number of printers capable of “direct”", "printing is known.", "Direct printing in the context of the present invention means that the printer is placed on the image receiving medium, usually manually, and the printing means of the printer or the entire printer then scans over the image receiving medium in the printing operation.", "Thus, the medium is not fed through the printer—as in most office printers—but the printer moves over the medium.", "Such a printer is known from EP 564297-A.", "The printer has an ink jet print head which scans in two orthogonal directions over the image receiving medium, onto which the printer is placed manually.", "The printer is connected to a computer and capable, e.g. of printing addresses onto envelopes, but can also be used separately from the computer for printing data downloaded from the computer to the printer.", "Another ink jet printer to be placed on a printing medium is disclosed in U.S. Pat. No. 5,634,730.", "This printer is provided with a keyboard for data inputting, but can also print images downloaded from a computer.", "The print head scans over the image receiving medium along a special path, e.g. helically or like a pendulum.", "DE 3142937-A refers to a so-called hand stamp which is placed manually on the image receiving medium.", "It can print data downloaded from an accounting machine, or images consisting of user-selected fixed phrases.", "The hand stamp has a thermal print head and an ink ribbon for printing.", "The direct printers known in the prior art are thus capable of printing an image onto an image receiving medium, and make use of a scanning print head.", "JP-6286227 discloses an electronic stamping apparatus which includes a pressure detection means that detects whether the pressure applied to an object is in a prescribed range, and a control means that controls scanning of a thermal transfer head based on the detection by the pressure detection means.", "This requires contact between the print head and the surface to be printed, in contrast to the printers described herein where the print head is spaced from the image receiving medium.", "SUMMARY OF THE INVENTION It is an aim of the present invention to improve the quality of images which are printed by the so-called direct printers.", "According to various aspects of the invention, this can be done in a number of different ways.", "According to one aspect of the invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium at a printing location and defining an area over which printing is effected;", "a printing mechanism operable to effect printing over said area with the housing at said printing location;", "means for detecting relative movement between the image receiving medium and the housing during printing;", "and a controller for inhibiting printing when such relative movement is detected.", "The means for detecting relative movement may be for example a scanner head, mouse ball etc.", "Thus, any relative motion detected during the print cycle may be used to interrupt or terminate the print cycle.", "According to another aspect of the invention there is provided a printer comprising: a housing arranged to be manually position on an image receiving medium at a printing location and defining an area over which printing is effected;", "a printing mechanism operable to effect printing over said area with the housing at said printing location;", "means for detecting orientation of the housing with respect to the image receiving medium during printing;", "and a controller for inhibiting printing when an orientation other than a correct predetermined orientation is detected.", "The means for detecting orientation of the housing can be for example a tilt sensor.", "Thus, the tilt sensor enables the print cycle to be inhibited unless the printer is positioned in the correct orientation.", "According to a further aspect of the invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium and defining an area over which printing is effected;", "a print head having a plurality of ink jet nozzles and mounted in said housing for travel within said housing relative to the image receiving medium to effect printing, said print head having an extent of travel which extends in a region outside the printing area;", "a controller for actuating said ink jet nozzles in said region as a maintenance procedure;", "and a set of absorbent strips arranged in said region for receiving ink ejected from the jet nozzles during the maintenance procedure.", "By using the unprintable area for interim “spitting”,—the print function can be maintained by preventing individual jets from blocking.", "The absorbent strips which are used to catch any drops of ink spat out may be replaceable.", "According to a further aspect of the present invention there is provided a printer comprising: a housing arranged to be manually positioned on an image receiving medium at a printing location and defining an area over which printing is effected;", "a print head mounted in said housing for travel within said housing relative to the image receiving medium to effect printing;", "a motor for driving said print head under the control of a drive signal;", "and a controller for generating the drive signal for the motor wherein the controller includes fault condition detecting means which are operable to detect when the drive signal exceeds a predetermined limit and to inhibit printing in said fault condition.", "In the described embodiment, the drive signal is an electric current which is supplied to the motor for causing movement of the print head.", "For an X-Y movement, there are two motors, one for moving the print head along an axis in an X direction and the other for moving the axis itself in a Y direction.", "Under normal printing loads, the drive current to the X-Y drive motors will follow a repeatable profile.", "Should the printing mechanism jam or encounter a higher resistance than normal, for example when printing on an uneven surface, the drive motor current will rise.", "By setting the boundaries that encompass the normal operating currents, current outside these boundaries may be detected as a fault condition and used to inhibit printing.", "In another aspect, the invention provides a printing system comprising: a printing unit;", "a base station configured to receive the printing unit when not in use and having means for detecting return of the printing unit to the base station;", "and wherein a maintenance sequence for the printing unit is initiated on detection of return of the printing unit to the base station.", "In another aspect the invention provides a printer comprising: a housing arranged to be manually positioned on an image receiving medium and having an opening defining an area over which printing is effected;", "a print head having a plurality of ink jet nozzles and mounted in said housing for travel within said housing relative to the image receiving medium to effect printing, said print head travelling at least within said opening and over said area to effect printing;", "and a cover removably attachable to said housing to close said opening when said printer is not in use.", "For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a printer, a base station and a computer;", "FIG. 2 shows the print mechanism of the printer;", "FIG. 3 a shows the underside of the printer with absorbent strips;", "FIG. 3 b is a perspective view illustrating the use of absorbent strips;", "FIG. 3 c is another perspective view illustrating the use of absorbent strips;", "FIG. 4 a is a view of a mechanism for fixing the print head in the printer;", "FIGS. 4 b and 4 c illustrate how the arrangement of FIG. 4 a functions as a detector;", "FIG. 4 d illustrates an embodiment of a motion detector;", "FIG. 5 illustrates the operation mode of the printhead;", "FIGS. 6 a and 6 b illustrate a tilt sensor;", "and FIG. 7 illustrates the printer with a dust cover.", "DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a printing system consisting of a computer 10 , a computer controlled display 12 , which is in the described embodiment of the invention a CRT, a keyboard 14 linked to the computer 10 by means of a cable 16 , another cable 18 , connecting the computer 10 with a base station 20 , which is connected to a printer 24 by means of a cable 22 .", "Thus, the printer 24 is linked to the computer 10 via the cables 18 , 22 and the base station 20 .", "As known in the prior art, the computer 10 comprises a processor on which a software is running, comprising an operating system, a printer driver to enable printing with the printer 24 from the operating system, and a software application by which data can be created, selected and formatted on the PC, for defining image patterns to be printed by the printer 24 .", "The software application can be activated in a number of ways: selected by the user at start-up or from the desktop: the user places the software application in the start-up directory or creates an icon on the desktop;", "from within another application: the user invokes the software application from a button (displayed on the display 12 ) in the toolbar of another software application;", "from the handheld printer 24 itself: if the application is not running, the user presses a print button 34 on the handheld printer 24 , which will automatically invoke the software application in the first instance.", "Another possibility to activate the software application on the computer 10 for controlling the printer 24 is to lift the printer 24 off the base station 20 .", "A switch 32 is provided in the base station 24 sensing the presence or absence of the printer 24 by means of a pin 30 .", "When the printer 24 is placed upon the base station, the pin 30 is depressed, and the switch 32 is open.", "In the case that the printer 24 is removed from the base station 20 , the pin 30 which is biased in the vertical direction moves upwardly and the switch 32 opens.", "The switch is connected via some electronic circuits to the computer 18 and activates the software application for printing.", "The base station 20 is connected to the computer 10 by means of the cable 18 , which can be a parallel or a USB cable.", "Electric power is supplied to the base station 20 by a separate mains transformer, but could also be supplied from the computer via the cable 18 , preferably when the cable 18 is a USB cable.", "The cable 18 can be hard wired to the base station 20 , or connected to a socket of the base station, which is preferably provided at the rear thereof.", "When the printer 24 is not in use, the handheld printer will be placed in the base station 20 .", "The base station 20 will ensure that the ink jet print head of the printer 24 is protected when not in use by a capping device that will be automatically triggered whenever the printer is inserted into the base station 20 .", "The base station 20 will also cause the print head of the printer 24 to eject ink into a reservoir and mechanically clear the surface of the print head.", "These measures are necessary to maintain optimum print quality.", "The umbilical cable 22 connects the base station 20 to the hand held printer 24 , providing both power and data.", "A LED on the printer will indicate that power is on.", "The printer 24 is removed from the base station 24 and positioned on the surface to be printed.", "The length of the cable 22 limits the distance of travel from the base station.", "In another embodiment of the invention, the printer is arranged to be disconnected from the base station by unplugging the umbilical cable 22 and moved to another location where printing of the contents of on-board memory, i.e. downloaded image data, can be effected.", "The user will employ scroll buttons on the printer to select the required print data, which appear in a small LCD.", "Once a selection has been made, pressing the print button 34 will activate printing.", "Having selected the data to print using the software application (or the scroll buttons on the printer), the user will activate printing from the print button 34 on the hand held printer 24 itself.", "Print alignment is achieved visually through a transparent window 36 in the printer casing.", "This window 36 can also be opened for inserting an ink cartridge into the printer 24 before use.", "The cartridge is then clamped in a carriage of the printer 24 .", "The window 36 must be closed before printing.", "The user can choose from a range of coloured and special inks.", "Changing a cartridge is achieved by lifting a retaining lever and extracting the cartridge in use and replacing this with a new or different colour cartridge in the way described above.", "If the removed cartridge still contains ink and is to be reused it must be capped to avoid the ink drying out.", "Alternatively a Think jet type head from Hewlett Packard may be used which utilises a different type of ink which does not dry out in the print head.", "The printer 24 contains a print mechanism with the ink jet print head having a number of print nozzles, and an ink supply.", "The print head is moved by means of motor driven scanning means within the housing in two (generally orthogonal) directions such that a rectangular area can be imprinted through an aperture of the printer 24 at the bottom of its housing.", "Thus, the printer 24 is placed manually on an image receiving medium and—when the print button 34 is depressed—the print head scans over the medium and imprints it by spitting ink droplets onto it.", "FIG. 1 shows the printer 24 , base station 20 and computer 10 linked by cables.", "In an embodiment, it is possible to replace one or all of these links by a wireless link such as a low power RF link or an infra-red link.", "FIG. 1 also shows the presence of a “Smart Card”", "reader 28 in the base station 20 .", "Smart cards 26 , i.e. memory cards, may be used for storing data or images or as a substitute for additional RAM in the base station.", "Spare cards may be stored within the base station where a storage compartment is provided (not shown).", "In the case that the printer 24 is powered only by batteries, rather than having the cable 22 transmitting power from the base station 20 , the amount of charge remaining in the batteries may be monitored an displayed on a display of the printer 24 , and/or on the display 12 of the computer 10 .", "If rechargeable batteries are used, the battery monitoring system could also be used to control the charge/discharge cycle of the battery pack to maximise battery life.", "This could also enable rapid recharging of the batteries.", "Such a battery management system could also indicate that there was sufficient energy remaining in the battery pack to complete the current task.", "The print mechanism of the printer will now be described with reference to FIG. 2 .", "The printer 24 has a housing 200 , the underside of which can be abutted against the surface of the image receiving medium to be printed.", "A print face 11 is defined by the scanning range of an ink jet print head cartridge 126 which can be replaced using the cartridge release mechanism described above.", "The ink jet print head cartridge 126 is mounted for movement along a write axis 128 by virtue of cooperating lead screw 130 and nut 132 .", "The movement is controlled by a motor 134 (stepper or DC depending on the nature of the print head).", "The position of the write axis 128 can be altered by an indexing axis lead screw and bush 136 controlled by a further stepper motor 138 .", "Reference numeral 140 designates a stability bar which extends parallel to the write axis 128 , the ink jet print head cartridge 126 being mounted between the write axis 128 and the stability bar 140 .", "Reference numeral 142 designates an indexing axis stability bar and bush.", "If a Think jet print head is used, a DC motor and encoder may be used in place of a stepper motor.", "The printer also includes an electronic controller 100 having a microprocessor for controlling movement of the motor 34 and generating signals for controlling the print head and having a buffer memory for storing data.", "The microprocessor is capable of converting data from a computer to which the device is connected into a format suitable for driving the print head.", "The buffer memory can store information in a variety of formats to enable the printer to work with a variety of computer equipment.", "In FIG. 2, the line 120 defines the extent of travel of the print cartridge 126 in the X and Y directions.", "Referring now to FIG. 3, a print area 122 which is denoted inside the dotted lines 122 a is defined which does not use up the full extent of travel of the print head cartridge 126 .", "Additional travel is required so that the print head can be accelerated/decelerated to and from optimum print speed and hence firing frequency.", "If print occurs during acceleration/deceleration, it is necessary to deviate from the print head specified firing frequency and print quality will deteriorate.", "FIG. 3 a shows the underside of the printing apparatus with all of the drive features removed for the sake of clarity.", "Thus, it discloses only the travel area 120 , the print area 122 and absorbent strips 124 .", "These absorbent strips are placed along the edges of the area of travel of the print head and outside the printing area 122 .", "These absorbent strips allow maintenance of the print head cartridge 126 by allowing ink to be ejected outside the print zone in order to purge the print nozzles and reduce the risk of clogged nozzles.", "Thus, the unprinted region between lines 120 and 122 a is used for interim spitting to maintain the print cartridge function by preventing individual jets from blocking.", "The strips of absorbent material may be replaced and are attached to the base of the printer and used to collect any drops of ink spat out to help maintain the print cartridge print quality.", "The strips should extend beyond the print head travel area to increase their effective ink capacity.", "Ink will wick out from the actual “spit”", "position to the extreme edges of the strips.", "FIGS. 3 b and 3 c illustrate the concept in more detail, with extraneous components removed for the sake of clarity.", "That is, in FIG. 3 c , reference numeral 124 denotes a rectangular absorbent strip.", "Reference numeral 230 denotes a thin fixed guide mounted on the bottom face of the printer 24 in the centre of which a rectangular aperture is provided (see also FIG. 3 b ).", "The print face is defined within the rectangular aperture.", "The guide is shown on the substrate in FIG. 3 b to illustrate its function to allow the print cartridge 126 to pass over it to print to the edge of the print area defined by it.", "FIG. 4 a illustrates how a print cartridge 72 is mounted in the printer 24 .", "A metal (or plastics) base plate 60 is mounted for scanning motion along the direction indicated by arrow A. The necessary mechanism for scanning in this direction is not shown in FIG. 4 a , for the sake of clarity.", "On the base plate 60 , a first guide rail 62 is provided, and a second guide rail 64 .", "Both guide rails 62 , 64 extend in a direction which is orthogonal to the direction of movement of the plate 60 .", "Additionally, two wheels 78 are provided, around which a drive belt 66 is located.", "The drive belt 66 is preferably toothed and extends parallel to the guide rails 62 , 64 .", "Further, a pin 70 is provided on a pin holder 68 , the latter being fixed to the drive belt 66 .", "The print cartridge 72 provided with an ink supply and nozzles for depositing the ink onto an image receiving medium is provided with three snap-on bearings 80 , 82 , 84 .", "The bearings 80 and 82 are arranged to be snapped (or clipped) into the first guide rail 62 , and the bearing 84 is arranged to be snapped into the second guide rail 64 .", "Thus, the cartridge 72 can be slidably fixed to the guide rails 62 , 64 and travel along the longitudinal axis of the guide rails.", "The pin 70 engages in a hole 86 of the cartridge, such that a driving connection between the drive belt 66 and the cartridge 72 is established.", "An electrical connector is incorporated in the pin 70 so that the drive signals can be transmitted to the print head.", "A dynamic cable (not shown) links the electrical connector with the drive circuitry elsewhere in the product.", "When the belt is driven (by means of a corresponding motor, not shown in FIG. 4 a for the sake of clarity, but it could drive the belt 66 through the rectangular window in the base plate 60 ), the cartridge 72 travels along the guide rails 62 , 64 .", "In order to control the print head of the cartridge 72 , the printer's control electronic requires information on the position of the print head.", "Thus, a pinwheel 74 engaging the printed medium is provided on the cartridge.", "The pinwheel 74 rotates when the cartridge 72 moves along the guide rails 62 , 64 and its rotation is detected by means of a motion detector 76 .", "The pinwheel 74 allows for the detection of the flatness of a substrate to help maintain print quality.", "As the pinwheel rotates, its rotation is detected by the motion detector 76 and a signal is produced.", "The pinwheel only rotates when the print cartridge is the correct distance from the substrate and the wheel is in contact with the substrate.", "At the end of each print pass, when the print cartridge is indexed forward ready to print the next pass, the pinwheel is held clear of the substrate to prevent damage.", "Alternatively a castor or track ball which can rotate about two orthogonal axes could be used.", "If the pinwheel loses contact with the substrate during the normal printing pass, the wheel no longer rotates, the signal is lost and the print cycle is inhibited.", "The base plate 60 and the pins on which the wheels 78 are mounted, and the guide rails 62 , 64 are unitary.", "Thus, the base plate 60 is produced as a unitary unit, e.g. by die casting, in order to simplify constructions and minimise component cost.", "It should be noted that a movement along the direction indicated by the arrow A is not necessary when the cartridge 72 contains a print head having a width sufficient to print the entire image receiving medium in one scan.", "FIGS. 4 b and 4 c illustrate in more detail how the arrangement of FIG. 4 a operates to implement “no contact, no printing.”", "In FIGS. 4 b and 4 c , the first position of the print cartridge 72 is shown outlined in a full black line and denoted position A. The second position is denoted by a dotted line and is denoted position B. The second position is shown to be over a small dip in the substrate such that the pinwheel 74 loses contact.", "FIG. 4 b illustrates how, in moving from position A to position B, the pinwheel 74 loses contact with the substrate over the small dip.", "FIG. 4 c illustrates the detector 76 in more detail.", "Each detector comprises a light emitter 76 a and a light sensor 76 b .", "In position A, light from the emitter 76 a reaches the sensor 76 b .", "In position B, it can be seen that the small dip in the substrate causes light from the emitter 76 a to be reflected at an angle such that it does not reach the light sensor 76 b .", "Thus, a fault condition is detected.", "Thus, although the primary function of the pinwheel 74 and motion detector 76 is to monitor surface contact, it can also be used to detect movement of the printer relative to the substrate.", "In particular this may be achieved by comparing the actual signal received from the detector with a reference signal, the reference being generated by a calibration operation where the printer is held in contact with a substrate and not allowed to move while the printer prints a test pattern.", "An alternative arrangement could be to mount at least two separate pinwheel sensors orthogonally with respect to one another within the body of the printer.", "When the printer is in contact with the substrate and in the printing position, no movement signal will be generated by these sensors.", "If relative movement occurs between the printer and the substrate, a signal will be generated by one or both of the sensors and a fault condition flagged.", "A further movement detection technique could be to use a two dimensional detection system as illustrated in FIG. 4 d .", "A heavy ball 210 has a high friction outer surface against which rests two orthogonal shafts 212 , 214 .", "Attached to these shafts are respective rotary encoders 216 , 218 .", "When the printer contacts the substrate, the ball rests on the substrate and any movement of the printer relative to the substrate is converted to a movement of one or other or both of the encoders.", "FIG. 5 illustrates how scanning is performed over the image receiving medium.", "Most ink jet printers known in the prior art accelerate the print cartridge from rest to normal printing speed prior to firing the ink droplets.", "This simplifies the control of ink droplet spacing and allows the print head to be fired at a optimum frequency, but the additional space required to accelerate the print cartridge increases the overall size of the product.", "The printer described here is hand held and thus requires that the overall dimensions are minimised.", "The control system of the print cartridge 72 thus provides the ability to print as the print cartridge assembly is accelerating—during printing of the left margin 90 of the image receiving medium 48 ′—and decelerating—during print of the right margin 90 ′ of the image receiving medium 48 ′—at the start and finish of each sweep of the mechanism thus enabling the product dimensions to be minimized for a given size of the print area on the image receiving medium.", "The drive signals issued by the controller 100 to the DC motors 134 and 136 thus follow a repeatable profile under normal printing loads.", "Should the mechanism jam or encounter a higher resistance than normal, the drive motor current requirement for the motors will rise.", "If boundaries are set that encompass the normal operating currents, then currents outside this area may be detected as a fault condition and the appropriate action taken to stop printing.", "Thus, reverting to FIG. 2, the DC motor 134 is controlled by drive signal 154 and the DC motor 138 is controlled by drive signal 158 .", "Feedback signals 164 and 168 respectively return the back EMF conditions of the motor to the controller 100 .", "This allows the controller to monitor the profile boundary and to detect the fault condition.", "It is important when the printer 24 has been aligned at a print location and is executing printing that the printer is correctly oriented while printing is being effected.", "That is, it is important that the printer 24 is placed squarely at the print location and is not tilted at an angle.", "That is, the print head 126 should desirably move in a plane parallel to the plane on which printing is to be effected.", "The tilt sensor of FIGS. 6 a and 6 b allows this to be achieved.", "The tilt sensor comprises a housing 200 which defines therein a part-spherical or “bowl-shaped”", "surface 202 .", "As can be seen, FIG. 6 b is a section taken along lines VI—VI of FIG. 6 a , but with the tilt sensor in a different position in each figure.", "At the lower-most point of the part-spherical surface 202 , a microswitch 204 is located.", "A ball 206 rolls freely on the part-spherical surface 202 and can roll in any radial direction.", "In FIG. 6 a , the tilt sensor is shown in its properly oriented position, with the ball 206 located over the microswitch 204 .", "This state is detected as a safe state, and printing is allowed to continue while the ball remains in that position.", "If however the unit moves, the ball will roll away from the centralised position over the microswitch, allowing the microswitch 204 to detect the absence of the ball 206 , as illustrated for example in FIG. 6 b .", "This is detected as a fault condition, and printing is inhibited.", "This allows movement of the printer during printing to be detected and printing to be inhibited accordingly.", "It will also be apparent that if the printer is placed at the printing location in anything other than the correct orientation, the ball 206 will not be over the microswitch 204 and thus the fault condition will immediately be detected even prior to printing.", "The printer must be properly aligned vertically before printing can be effected.", "FIG. 7 illustrates the printer 24 with a sealing lid or dust cover 300 attachable to the printer 24 to close the print face 11 in the base of the printer.", "In addition, a window 302 is hinged to the housing of the printer 24 whereby the window can be releasably hinged or fixed to the printer 24 .", "In accordance with one embodiment, when the printer 24 is returned to the base station 20 , the printer 24 automatically cycles through a service routine to maintain the print cartridge performance.", "This sequence is triggered by a switch 304 (FIG.", "1) in the base station which senses return of the printer to the base station 20 .", "The service routine can be determined by the supplier of the ink jet cartridge such as to maintain the print cartridge performance." ]
FIELD OF THE INVENTION This invention refers to the mineral-herbal preparation which is applied for prevention of the development of neuropathies in persons suffering from diabetes. By this invention, the process of apoptosis caused by accumulation of Ca 2+ ions in cytoplasm of nerve cells is stopped. DESCRIPTION OF THE INVENTION The technical problem which was set before the inventor, and the solution of which is presented in this patent application, consists in the invention of the mineral-herbal preparation, which is applied for prevention of the development of neuropathies in patients suffering from Diabetes mellitus, which will have the following characteristics: 1) it reduces the concentration of glucose, 2) the process of depositing of Ca 2+ ions into nerve cells can be stopped by it, 3) it stops the process of apoptosis in nerve cells stimulated by depositing of Ca 2+ ions, 4) the process of phagocytosis of apoptotic bodies is absent, 5) it stops the process of creating immunoglobulin on myelin fibres of the nerve membrane, 6) it reduces the depositing of immunoglobulin on axons, 7) it reduces the immunological destruction of axons mediated by the complement, 8) pain caused by diabetic neuropathy is absent, 9) it contains substances for elimination of free radicals, 10) it contains the daily dose of B complex vitamins, 11) it leads to ionic exchange, 12) it does not pass through villi, 13) it leads to ionic exchange through intestine-blood barrier, 14) its particles are of micron and submicron size, 15) its fragmentation is carried out in the jet mill, 16) it is mechanically treated, 17) it is chemically treated, 18) it is thermally treated, 19) the concentration of Na˜ions is reduced, 20) it is enriched with Ca2˜ions, 21) by mechanical treatment, the maximum capacity of the ionic exchange is achieved, 22) by thermal treatment, the maximum capacity of the ionic exchange is achieved, 23) by chemical treatment, the maximum capacity of the ionic exchange is achieved, 24) the dose in relation to the natural clinoptilolite is reduced, 25) the capacity of the ionic exchange in relation to the natural clinoptilolite is increased, 26) it is suitable for oral administration, 27) no noticeable harmful side effects appear even with large daily doses, and in case of a long-term use, 28) it is not toxic. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a graph of the differential thermal analysis of SM clinoptilolite. FIG. 2 is a graph of the size distribution of particles of SM clinoptilolite. FIG. 3 is a graph of glucose concentration in diabetic CBA mice. FIG. 4 is a graph of glucose concentration in diabetic NOD mice. FIG. 5 is a graph of the amount of water drunk by mice. FIG. 6 is a graph of the amount of excreted urine by mice. FIG. 7 is a cross-section through n. ischiadicus of diabetic mice. FIG. 8 is another cross-section through n. ischiadicus of diabetic mice. FIG. 9 is Table 1, a table of mice body mass. FIG. 10 is Table 2, another table of mice body mass. FIG. 11 is Table 3, showing the concentration of Ca 2+ in mice serum. FIG. 12 is Table 4, showing the concentration of Ca 2+ in mice serum . FIG. 13 is Table 5, showing the presence of neuropathy in diabetic CBA mice. FIG. 14 is Table 6, showing the presence of neuropathy in diabetic NOD mice. FIG. 15 is Table 7, showing the percentage of apoptotic bodies in CBA mice. FIG. 16 is Table 8, showing the percentage of apoptotic bodies in NOD mice. TECHNICAL PROBLEM Diabetes mellitus is a hereditary metabolic disturbance, which becomes expressed under the influence of the environment factors. Its main characteristic is a relative lack of insulin, its ineffectiveness, that is, poor or no use of the hydrocarbons entered in the organism which results in the increased level of glucose in blood or hyperglycemia. Diabetes of Type I, that is, IDDM (insulin dependent diabetes mellitus) is characterized by progressive autoimmune process of destruction of f3 cells of Islets of Langerhans by T lymphocytes (Eisenbarth, G S. New Engl. J. Med. 314:1360-1368, 1986). More precisely, IDDM is the result of the destruction of beta cells mediated by CD4+and CD8+cells and the function of antigen presenting cells (APC) (Frque F., Hadzija M., et al., Proc. Natl. Acad. Sci., USA, 91:3936-3940, 1994). NOD (non-obese diabetic) mice develop the classical picture of diabetes which is completely identical to IDDM in people (Makino S., et al., Expl. Anim. 29: 1 (1980)). Furthermore, chemical diabetes caused by alloxan in mice also develops the picture of diabetes with all the accompanying symptoms identical to the human form of diabetes of Type I (Dunn J. S., et al., Lancet II: 384-387, 1943). The purpose of the therapy of diabetes is the normalization of the following parameters: the concentration of glucose in blood, the concentration of lipids, and the absence of glucose and acetone in urine. The therapy is carried out in six ways: by diabetic nourishment, by physical activity, by education and self-control, by oral hypoglycemic medicaments, by exogenous insulin or by transplantation of pancreas or islets. Insulin Insulin is a polypeptide hormone consisting of the 51 amino acid. It is made of two polypeptide chains which are mutually connected by two disulfide bridges, and it is created in β cells of Islets of Langerhans of the pancreas, from where it is secreted into blood. Only 25% of the total insulin from the pancreas enters blood stream daily, and most of it remains stored in p cells (Huton J. C., Diabetologia 32: 271-281). The main stimulus to secretion of insulin is glucose which concurrently stimulates the synthesis of insulin as well. Except for it, secretion is also stimulated by: particular ingredients of food (amino acids, higher fatty acids) some gastrointestinal hormones (secretin, cholecystokinin, gastrin . . . ). The secretion curve has a biphasic shape: a sudden short-term increase of secretion is followed by a slower, long-term secretion. The first phase corresponds to the release of the stored insulin, and in the second phase, new synthesized insulin is released. Secretion of Insulin is Inhibited by: somatostatin catecholamines through β adrenergic receptors hypothalamus through n. splanchnicus. Insulin acts through insulin receptors which are located on the outer side of cell membranes of target organs (liver, muscles, fat tissue), so that, bound through the so-called “second messenger” in that way, it causes changes of cell enzymes (activation and inhibition) and the change of the cell membrane. Because of that, the action of insulin depends, beside on its concentration, also on the number and the affinity of insulin receptors. Physiological Effects of Insulin: by induction of enzymes, it stimulates the deposit of glucose in the liver in form of glycogens, inhibiting glycolysis as well it increases the synthesis of triglycerides and obstructs glucogenesis in the liver it increases the transport of glucose and amino acids into the muscle tissue where th synthesis of proteins and glycogens is increased it inhibits the hydrolysis of the stored triglycerides in the fat tissue, and activates lipase which decomposes lipoproteins. With the lack of insulin in diabetic patients, the synthesis of proteins is reduced, and a large quantity of free amino acids is available for glucogenesis. Besides, free fatty acids pass into blood in an increased extent, and from it to the liver, where they are decomposed to acetyl-CoA by β-oxidation, and the increased quantity of acetyl-CoA cannot be used in the citric acid cycle, but acetoacetic acid is made, which leads to ketogenesis. Oral Hypoglycemic Substances Oral antidiabetics are a support to secretion of endogenic insulin, or they prevent the decomposition of glucose, and they are effective in the presence of at least a small quantity of insulin. By the chemical structure, they are classified as preparations of sulfonylurea, biguanides and inhibitors of glycosidase (Pickup J C, Blackwell, 1997). Derivatives Of Sulfonylurea Historical subclassification: preparations of “the first generation”: tolbutamide, chlorpropamide preparations of “the second generation”: glybenchlamyde, glyquidon, glychlaside, glypiside Activity Mechanism For achieving of the hypoglycemic effect of the derivatives of sulfonylurea, at least partly preserved production of insulin in β cells is necessary. On the molecular level, the basic mechanism of activity is the inhibition of the so-called K + channels dependent on ATP. The blockade of ATP dependent K + channels consequentially causes the increased entering of Ca 2+ into the cell which mobilizes the secretory granules with insulin according towards the cell membrane and stimulates their exocytosis. Pharmacokinetics After the peroral application, faster resorption of all the preparations is achieved, which mostly bind themselves to plasma proteins. They are mostly excreted by urine, and some through bile as well. Side Effects They cause side effects in form of gastrointestinal disturbances (anorexia, nausea), skin reactions (urticarias), cholestatic jaundice, and intolerance to alcohol. Concurrent taking with some medicaments (e.g. sulfonamides, phenylbutazone, salidylates . . . ), which repress the preparations from the connection with plasma proteins, can strengthen the hypoglycemic action of the preparations of sulfonylurea (Scheen A. J., et al., Drugs 55:225-236, 1998). Biguanides Among biguanides we include: metformin, buformin and fenformin. Activity Mechanisms The mechanism of the activity of biguanides is not quite known yet. It is supposed that those medicaments reduce the concentration of glucose in blood of diabetic patients, probably by increasing the degree of utilization of glucose in peripheral tissues, by stimulation of glycolysis, by inhibition of glyconeogenesis in liver, by reduction of the intestinal resorption of glucose, and by lowering the level of glucagon in the plasma (Pickup J. C., Blackwell, 1997; Scheen A. J., et al., Drugs 55: 225-236, 1998). Pharmacokinetics After the resorption in the digestive tract, biguanides are bound to plasma proteins. They are excreted by kidneys, and the halftime of semi-elimination is different depending on the preparation. Side Effects Side effects in form of gastrointestinal disturbances (nausea, vomiting, metal taste in the mouth) are frequent, which can also be the first sign of the most difficult side effect—lactoacidosis (disturbance of metabolism with the increase of the concentration of lactic acid in tissues and in blood). Lactoacidosis is more common in patients with the damaged function of kidneys and liver, in pregnancy, in increased consumption of alcohol. They have a favourable therapeutic effect in obese patients. They are also used in combination with preparations of sulfonylurea and inhibitors of α-glucosidases. α-Glucosidase Inhibitors Among inhibitors of α-glucosidase, we include: acarbose, myglytol, voglybose, castanospermin Acarbose Activity Mechanism Acarbose is pseudotetrasaccharide of microbiological origin from the genus Actinomices . It is a competitive and reversible inhibitor of intestinal enzymes of glucoamylase, saccharase, maltase, dextrinase, as well as pancreatic amylase. Structurally, it is similar to oligosaccharides which develop by hydrolysis of starch. An acarbose molecule consists of acarviosin and a unit of glucose mutually connected by α1-14 glycoside bonds. For the inhibition of α-glycosidase, the secondary group of acarviosins is responsible, which prevents the carboxyl group of enzymes to protonate the oxygen of the glycoside bond. Thus, due to the reversible process, the hydrolysis of oligosaccharides is postponed, which reduces absorption of glucose in blood after a meal (Clissold S. P., et al., Drugs 35: 214-243, 1989). Pharmacokinetics After oral application, acarbose is absorbed only 1 to 4%. It metabolizes with the help of amylases of the digestive tract and intestinal bacteria. Antidiabetic Effect Acarbose in patients with NIDDM prevents hyperglycemia after a meal, reduces the concentration of glucose in blood and reduces the need for insulin. Contraindications Acarbose is contraindicated in patients with disturbances of digestion and absorption, with chronical diseases of liver, and during pregnancy and lactation. Development of Neuropathy in Diabetes Neuropathy is a frequent late complication in diabetes which affects somatic and autonomous nerves. Neuropathy appears in a certain percentage in diabetes Type I and in Type II (Greene D. A., et al., Diabetes Care 15: 1902-6, 1992). Peripheral nerve abnormalities in people or in animal model of diabetes are manifested by reduction of the conductibility of nerves, by shortening of axons, by reduction of the number of axons, connected with metabolic disturbance, including the changes of calcium signal. Studies carried out until now showed that the disturbance of homeostasis of Ions of calcium is a widespread occurrence in IDDM and NIDDM. The same change was noticed both, in people suffering from diabetes, and in animal models of diabetes, and that is the increase of the concentrations of Ca 2+ ions in cytosol. The increase of the concentration of calcium ions aids to the process of the natural way of dying (apoptosis) of nerve cells, but that process was shown in many other experimental models too. The latest researches showed that “the factors from the serum” have an important role in pathogenesis of diabetic neuropathy in patients with Type I diabetes. By incubation of β cells of islets of Langerhans in conditions of the culture of tissues, when the serum of patients with Type I diabetes was added to the medium, apoptosis with β cells L.o. was connected with the increase of the concentration of-calcium ions of L type. It was also shown that neuroblastoma cells showed a reduced growth, the increase of entering of Ca 2+ ions, that is, the increased apoptosis, if they were exposed to the serum of patients suffering from Type I diabetes with neuropathies. The complement of an independent, Ca dependent induction of apoptosis of nerve cells improves the appearance of autoimmune immunoglobulins in diabetes on nerve axons. Zeolites are a group of natural minerals of the basic structure of AlO 4 and SiO 4 tetrahedrons mutually bound by an oxygen atom. Their basic characteristic is that, by their structure, they are microcrystals with micropores of various diameters and of various composition dependant on origin. Until today, the known zeolites of natural, that is, artificial origin, are applied in industry; but also in medicine. EXAMPLES OF REALIZATION Natural clinoptilolite showed unfavourable chemical-ionic composition for this invention, due to a too low concentration of Ca 2+ ions. As such, it had to be submitted to the process of semi-synthesis whereby the replacement of Na + ions with Ca 2+ ions happens. Working Example 1 Semi-synthetic Clinoptilolite Clinoptilolite is heated to 500° C. for the purpose of eliminating of molecular water. By a screw conveyor, clinoptilolite treated in that way is in a controlled way and continuously brought to a high temperature vessel from which it is transported under pressure into a jet of compressed air with the speed of 510 m/s, so that particles of minerals accelerated in that way collide with an obstacle prepared for that purpose in order to be fragmented to the necessary size. Particles created in that way are submitted to ionic exchange in the liquid phase enriched with Ca 2+ ions by standard procedure (Breck D W, J.Chem Educ 41:678, 1964; Fedorov V A, et all, Zh Fiz Khim. 38: 1248, 1964; Wolf F, Foertig H. Kolloid Z.-Z. Polymere 206: 48, 1965; Sherry H S, Adv. Chem Ser, 101: 350, 1971; Brooke N M, Rees L V C, Adv Chem Ser. 101: 405, 1971; Barrer R M, Klinowski J Phil Trans. 285: 637, 1977). Thus prepared clinoptilolite is further used for preparation of the mineral-herbal preparation from the invention. In order that the Ca—form of clinoptilolite be achieved, after the temperature treatment, clinoptilolite was submitted to semi-synthetic exchange in the liquid phase and enriched with Ca 2+ ions. An ionic exchange follows: Working Example 2 Ionic Exchange Na-clinoptilolite +Ca 2+ (L)⇄ Ca-clinoptilolite +2Na + Clinoptilolite SM prepared in that way was used in preparation of the mineral-herbal preparation from this invention. The composition of the mineral-herbal preparation includes also: Working Example 3 Extract of Nettle Root, Stalk and Leaf URTICAE RADIX, HERBA ET FLOS URTICA DIOICA L ., URTICACEAE—NETTLE The extract from the Urtica dioica is obtained in by standard procedure, shortly: the mixture of the nettle root, stalk and leaf, was cut into tiny pieces, and from plant substance cut in that way extract was made in 3-8 days. Extraction can be done with water, with acetone, ethanol, 70% of ethanol and 30% of water, alcohol. Solvent was removed from the extract by evaporator R-114, Buchi, Switzerland, and by a further procedure, the extract of nettle was frozen in liquid nitrogen and then lyophilized by standard procedure. The obtained powder had all the characteristics described below and used in popular medicine. Nettle contains many minerals, calcium 490 mg %, iron 10 mg % (most than all the self-grown vegetables), a little sulfur, sodium and potassium, quite a lot of organic acids, vitamin C, depending on the season, up to 174 mg %, vitamin B1, histamine, chlorophyll, some enzymes. People have used nettle against anemia for a long time, which is also justified for anemias arisen due to the lack of iron. That is in accordance with the popular belief that nettle has a positive effect on strengthening of defense powers of the organism. Tea from leaves of nettle stimulates the excretion of urine. For example, two week treatment increases the volume of urine and reduces the body mass. Taking nettle has a particularly favorable effect on diseases of prostate in older men. It stimulates the circulation and eliminates uric acid from the organism, so that it is recommended in case of arthritis and gout. It can help in healing of diseases of liver and bile. Popular medicine uses fresh nettle leaves. It prepares juice by pressing of fresh plant, then, tea, syrup and extract, and hot compresses are put on burns, cuts and inflamed hemorrhoids. Nettle preparations are applied externally in case of seborrhea and balding. Nettle seeds are given in case of tuberculosis and for treatment of lungs after bronchitis. It was recently discovered that the plant contains about 5.9 mg % of proteins. Working Example 4 ASTRAGALUS ASTRAGALI RADIX ASTRAGALUS MEMBRANACEUS (FISCH. EX LINK) Fabaceae The extract from the Astragalus membranaceus is obtained in by standard procedure, shortly: the root of astragalus is cut to tiny pieces, and from the plant mass cut like that, extract is made in 3-8 days. Extraction can be done with water, with acetone, ethanol, 70% of ethanol and 30% of water, alcohol. Solvent was removed from the extract by evaporation (Evaporator R-114 Buchi, Switzerland), the extract of astragalus was frozen in liquid nitrogen and lyophilized by standard procedure. The obtained powder had all the characteristics described below and used in popular medicine. Thus, astragalus is spread in the territory of eastern Mediterranean and southern and western Asia. The medicinal part of the plant are underground parts. Astragalus contains many active substances: Astragalosides from I to VII. Triterpene glycosides, flavonol glycosides, saponin. Tests on animals showed its immunostimulatory effect and protection of organism from the effect of toxins. It helps in illnesses of peripheral blood vessels and improves the peripheral circulation. Its antioxidant effect was proved, that is, soothing of the consequences of the liver cirrhosis. In popular medicine it is used for strengthening of organism, as an immunostimulator, diuretic, and in case of infections of upper respiratory tract. Notify extracts was mixed in adequate mass ratio. Working Example 5 Preparation of B Complex The basic source of B complex vitamines is preparation rich in proteins, hydrocarbons, lipids, minerals, vitamins and essential amino acids. As the basic source of vitamins of B complex was used from inactive Saccharomyces sp. a preparation rich in proteins, hydrocarbons, lipids, minerals, vitamins and essential amino acids. This preparation was used as the basic source of vitamins of B complex in the mineral-herbal preparation Except for the stated, the mineral-herbal preparation can, but need not contain other minerals too, like mordenite, montmorilonite. Working Example 6 Analyzed by Atomic Absorption Spectroscopy SM clinoptilolite, as fine dust, is chemically treated and analyzed by atomic absorption spectroscopy. The quality and quantity of the invention is analyzed by diffractometry by x-rays on the Siemens 500° D. diffractometer of CuK α radiation, in the region 20=4-80°. Working Example 7 Thermogravimetry Thermogravimetry of SM clinoptilolite, that is, the differential thermogravimetry was analyzed by the use of the device TA4000 Mettro-Toledo. Working Example 8 Size of Particles The size of particles of SM clinoptilolite is determined by the method of diffusion of the laser light on the device Mastersize XLB, Malven. Working Example 9 Experimental Diabetes Testings were made on two models of experimental diabetes. Experimental diabetes was caused by alloxan in CBA mice, in the dose of 75 mg/kg of body weight. After the appearance of the symptoms of diabetes, 3 mice were kept in each cage. NOD mice, which developed all the symptoms of diabetes, were taken in the experiment. In toxicological tests, the mineral-herbal preparation was admixed to the standard food for laboratory mice. This invention will now be shown with particular examples showing that, in case of diabetes, a syndrome is in question, and that, for a successful treatment of diabetes mellitus type I or II, it is not sufficient to apply the known medicine which has only the characteristic of a strong hypoglycemic effectiveness, but that the mineral-herbal preparation from the invention should be applied which helps the disturbed metabolism its entirety. Working, Example 10 Determining of the Level of Apoptosis The level of apoptosis was determined after cutting of the sample of the nerve in cryostat. To cut samples of 4 82 m, propidium iodine was added and the sample was analyzed under fluorescent microscope. Working Example 11 Presence of IgG on Nerves The presence of IgG on nerves was ascertained by colouring of nerves with antibodies on IgG conjugated with fluorescein. Working Examples 12 Diabetic animals which were receiving the mineral-herbal preparation with this composition: SM clinoptilolite of 50 mg, mordenite 15 mg, montmorilonite 15 mg, extract of astragalus 5 mg, extract of nettle 11.5 mg, B1 10 μg, B2 8 μg, B6 1.25 μg, B12 0.3 μg, with all the symptoms of diabetes, with 17.3 mM/L glucose in blood. Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured. During the first three days of the application of the mineral-herbal preparation, animals did not show the reduction of the symptoms of diabetes. The same was repeated in the next three days. The concentration of glucose in blood was above 18 mM/L, and the animals drank more than 30 ml of water daily. Further therapy also did not have a positive effect on symptoms of diabetes in CBA and NOD mice either. Here should particularly be pointed out that no significant developments were made for the purpose of reducing the level of glucose, and that the symptoms of diabetes were also not reduced. During the test, mice were moderately active. Working Example 13 Diabetic animals which were receiving the mineral-herbal preparation with this composition: clinoptilolite 180 mg, mordenite 27.5 mg, montmorilonite 22 mg, extract of astragalus 6 mg, extract of nettle 12 mg, B1 25 μg, B2 18 μg, B6 2.5 μg, B12 0.7 μg, with all the symptoms of diabetes, with 14.5 mM/L. glucose in blood. Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured. During the first three days of the application of the mineral-herbal preparation, animals did not considerably reduce the symptoms of diabetes. The same was repeated in the next three days, so that the volume of water drunk and the urine excreted was reduced by 50%. In the test of burdening with glucose, the mineral-herbal preparation did not show a hypoglycemic effect, but the curve of the assimilation of glucose was considerably more favourable in relation to untreated control mice, which is valid both for CBA diabetic mice, and for NOD diabetic mice. During the further therapy, through 6 months, the symptoms of diabetes were not eliminated, but they were considerably reduced. One should particularly point out here that for the purpose of reduction of glucose no significant developments were made, but that the symptoms of diabetes were considerably reduced. During the test, mice were moderately active. Working Example 14 Diabetic animals which were receiving the mineral-herbal preparation with this composition: clinoptilolite 600 mg, mordenite 60 mg, montmorilonite 80 mg, extract of astragalus 11 mg, extract of nettle 9 mg, B1 3.5 μg, B2 2 μg, B6 2.5 μg, B12 2.75 μg, with all the symptoms of diabetes, with 14.7 mM/L glucose in blood. Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured. During the first three days of the application of the mineral-herbal preparation, there was a reduction of the symptoms of diabetes. The quantity of water drunk and food eaten in the group of CBA diabetic mice and in the group of NOD diabetic mice was reduced considerably. The volume of urine excreted was also reduced. In the next three days, the symptoms of diabetes returned. The concentration of glucose in blood was over 15 mM/L, and animals drank about 25 ml of water daily. The further therapy did not have a positive effect on the symptoms of diabetes either. One should particularly point out here that for the purpose of reduction of glucose no significant developments were made, and also that the symptoms of diabetes were not reduced either. During the test, mice were moderately active. Pharmacological Data Toxicology No harmful toxic effects were ascertained if the animals were receiving the mineral-herbal preparation during 6 months, that is, one year. The effect of this mineral-herbal preparation on the concentration of glucose in blood was tested in control and diabetic CBA and NOD mice. The results were compared with the group of diabetic CBA mice which were not receiving the preparation. After 14 days, the animals were receiving the invention through a probe in the quantity of 50 to 400 mg on 25 grams of the body weight. On the 14 th day, the zero sample of blood (25 μL) was taken from the tail vein. Mice were submitted to the test of assimilation of glucose (OGTT). During the next 2 hours, in certain periods of time, blood samples were taken and the concentration of glucose in them was determined. The results are shown in FIGS. 3 and 4 . The concentration of glucose in diabetic CBA mice (10 mice per group) which were not receiving the preparation averagely amounted to 12.8±3.2 mM/L (FIG. 3 ). After 10, that is, 30 minutes from injecting of glucose, the concentration of glucose in peripheral blood of mice was strongly increased to values above 20 mml/L. During the next hour and a half, the concentration of glucose started to decrease, but it did not reach the values of the beginning concentration of glucose in blood (FIG. 3 ). However, in diabetic mice which were receiving the mineral-herbal preparation through 14 days, the concentration of glucose was considerably increased after injecting, just as it did in untreated mice. But in the following hour and a half, animals assimilated glucose more strongly and the concentration of glucose was approximately the same as the initial values of about 15 mmol/L (FIG. 3 ). in NOD mice (n=12) with active autoimmune process and all the symptoms of diabetes, the concentration of glucose in blood was about 17 mmol/L. After probing of glucose in those mice, no increase of glucose in blood during the next 10, that is, 30 minutes was noticed. But in NOD mice treated with the invention, the increase of the concentration of glucose in blood during the first 30 minutes after probing was noticed, and a slight decrease of the concentration of glucose, during the next hour and a half, towards the initial values (FIG. 4 ). Results of these tests showed that the mineral-herbal preparation does not have a direct hypoglycemic effect, but that the concentration of glucose still returns to the starting hyperglycemic value. However, it proved that the mineral-herbal preparation has a considerable effect on other symptoms of diabetes (FIGS. 5 and 6 ). Thus diabetic mice which received the invention by probe through 6 days drank considerably less water during the experiment in comparison with the initial values (p<0.001) (FIG. 5 ). Diabetic CBA mice which were receiving the mineral-herbal preparation for 6 days considerably reduced the volume of excreted urine during the experiment (p<0.001) (FIG. 6 ). During 6 months, mice were receiving the mineral-herbal preparation together with food each day. From Table 4 is evident that the mineral-herbal preparation did not show any harmful effect because the weight of control, healthy mice was not reduced, but grew during the experiment. Thus, the body weight averagely increased from the beginning 35 grams to 40 grams. But, in the group of CBA mice, there was a decrease of the body weight to about 26 grams during the experiment (Table 1). During the whole experiment, there was no increase of the body weight from the initial values in the group of diabetic mice (Table 1), which is a usual occurrence in case of diabetes. During the experiment, a decrease of the body weight was noticed in the group of diabetic NOD mice (Table 2). In the beginning of the experiment, the body weight was about 35grams, while in the end of the experiment the mice weighed approximately 30 grams (table 2) During 6 months of examining of the effect of the invention on diabetic state, the level of the concentration of calcium ions (Ca 2+ ) in the serum of control and diabetic mice (Table 3) was monitored. The concentration of Ca 2+ ions during the 6 months did not change in blood of diabetic CBA mice which were receiving the invention each day. But in the group of diabetic CBA mice, after the duration of illness of 6 months, there was a statistically significant decrease (p<0.05) of the concentration of Ca 2+ ions in the serum (Table 3). In the group of control, non-diabetic NOD mice, the body weight was constantly increasing during the experiment (Table 2). Similar results were also shown by mice with spontaneous diabetes (Table 4). The concentration of Ca 2+ ions did not change in the group of diabetic NOD mice which were receiving the invention each day. A considerable reduction of the concentration of calcium ions was measured in the group of diabetic NOD mice which were not receiving the mineral-herbal preparation (p<0.05) (Table 4). Animals from particular groups were sacrificed after 7, 90, that is 180 days. By patho-histological treatment, the level of neuropathy of the digestive tract (Tables 5 and 6) was ascertained. After 180 days, diabetic CBA mice which were not receiving the mineral-herbal preparation, developed diabetic neuropathy in 100% of cases. However, in diabetic CBA mice which were receiving the mineral-herbal preparation each day, the diabetic neuropathy was not observed (Table 5). The same experiment was also made with diabetic NOD mice. Diabetic NOD mice develop diabetic neuropathy in 100% of cases during 6 months (Table 6). Diabetic NOD mice, which were receiving the mineral-herbal preparation during 180 days did not develop diabetic neuropathy (Table 7). In order to check the extent of the damage of nerves, that is, to examine the presence of apoptotic bodies, on the day of sacrificing, samples of n. ischiadicus were taken from mice. The obtained results show that long-term diabetes has a considerable effect on the increase of the number of apoptotic bodies. In the group of diabetic mice, the number of apoptotic bodies was about 65% (FIG. 7 ). In controls (healthy mice), the number of apoptotic bodies was about 7%. Diabetic mice treated with the invention did not show a considerable increase of the number of apoptotic bodies in n. ischiadicus (FIG. 8 ). By immunofluorescent colouring, the presence of antibodies (IgG) on nervus ischiadicus was tested. Diabetic mice which developed all the symptoms of diabetic neuropathy showed a strong presence of IgG in n. ischiadicus (FIG. 7 ). Contrary to that, mice which were receiving the invention for 6 months did not have auto-anti-bodies on nerve axons of n. ischiadicus (FIG. 8 ). The percentage of apoptotic bodies is statistically considerably smaller in the group of mice (CBA and NOD) treated by the invention (Table 7 and 8). Further, after colouring with anti IgG conjugated with fluorescein, the percentage of positive neurons in the group of mice treated by the invention was between 6 and 9% (Table 7 and 8). In this patent application, specific realizations of this invention were shown. Those acquainted with this field know that various equations of this invention are possible. It should be pointed out that al such realizations of this invention are comprised by the range of patent claims that follow.
This invention refers to the preparation for elimination of neuropathies in diabetes. The preparation contains a combination of minerals and plant extracts. By its ionic exchange, the invention reduces considerably the process of apoptosis of nerve-cells, eliminates the process of activation of the immunologic system, and stops the immunologic reaction of auto-destruction of nerve-cells. Depositing of immunoglobulin on axons is absent, and neuropathic pain disappears. Furthermore, the preparation reduces the activity of free radicals, improves the regulation of glycemia and improves the recovery of axons which are already damaged.
Identify and summarize the most critical features from the given passage.
[ "FIELD OF THE INVENTION This invention refers to the mineral-herbal preparation which is applied for prevention of the development of neuropathies in persons suffering from diabetes.", "By this invention, the process of apoptosis caused by accumulation of Ca 2+ ions in cytoplasm of nerve cells is stopped.", "DESCRIPTION OF THE INVENTION The technical problem which was set before the inventor, and the solution of which is presented in this patent application, consists in the invention of the mineral-herbal preparation, which is applied for prevention of the development of neuropathies in patients suffering from Diabetes mellitus, which will have the following characteristics: 1) it reduces the concentration of glucose, 2) the process of depositing of Ca 2+ ions into nerve cells can be stopped by it, 3) it stops the process of apoptosis in nerve cells stimulated by depositing of Ca 2+ ions, 4) the process of phagocytosis of apoptotic bodies is absent, 5) it stops the process of creating immunoglobulin on myelin fibres of the nerve membrane, 6) it reduces the depositing of immunoglobulin on axons, 7) it reduces the immunological destruction of axons mediated by the complement, 8) pain caused by diabetic neuropathy is absent, 9) it contains substances for elimination of free radicals, 10) it contains the daily dose of B complex vitamins, 11) it leads to ionic exchange, 12) it does not pass through villi, 13) it leads to ionic exchange through intestine-blood barrier, 14) its particles are of micron and submicron size, 15) its fragmentation is carried out in the jet mill, 16) it is mechanically treated, 17) it is chemically treated, 18) it is thermally treated, 19) the concentration of Na˜ions is reduced, 20) it is enriched with Ca2˜ions, 21) by mechanical treatment, the maximum capacity of the ionic exchange is achieved, 22) by thermal treatment, the maximum capacity of the ionic exchange is achieved, 23) by chemical treatment, the maximum capacity of the ionic exchange is achieved, 24) the dose in relation to the natural clinoptilolite is reduced, 25) the capacity of the ionic exchange in relation to the natural clinoptilolite is increased, 26) it is suitable for oral administration, 27) no noticeable harmful side effects appear even with large daily doses, and in case of a long-term use, 28) it is not toxic.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a graph of the differential thermal analysis of SM clinoptilolite.", "FIG. 2 is a graph of the size distribution of particles of SM clinoptilolite.", "FIG. 3 is a graph of glucose concentration in diabetic CBA mice.", "FIG. 4 is a graph of glucose concentration in diabetic NOD mice.", "FIG. 5 is a graph of the amount of water drunk by mice.", "FIG. 6 is a graph of the amount of excreted urine by mice.", "FIG. 7 is a cross-section through n. ischiadicus of diabetic mice.", "FIG. 8 is another cross-section through n. ischiadicus of diabetic mice.", "FIG. 9 is Table 1, a table of mice body mass.", "FIG. 10 is Table 2, another table of mice body mass.", "FIG. 11 is Table 3, showing the concentration of Ca 2+ in mice serum.", "FIG. 12 is Table 4, showing the concentration of Ca 2+ in mice serum .", "FIG. 13 is Table 5, showing the presence of neuropathy in diabetic CBA mice.", "FIG. 14 is Table 6, showing the presence of neuropathy in diabetic NOD mice.", "FIG. 15 is Table 7, showing the percentage of apoptotic bodies in CBA mice.", "FIG. 16 is Table 8, showing the percentage of apoptotic bodies in NOD mice.", "TECHNICAL PROBLEM Diabetes mellitus is a hereditary metabolic disturbance, which becomes expressed under the influence of the environment factors.", "Its main characteristic is a relative lack of insulin, its ineffectiveness, that is, poor or no use of the hydrocarbons entered in the organism which results in the increased level of glucose in blood or hyperglycemia.", "Diabetes of Type I, that is, IDDM (insulin dependent diabetes mellitus) is characterized by progressive autoimmune process of destruction of f3 cells of Islets of Langerhans by T lymphocytes (Eisenbarth, G S. New Engl.", "J. Med.", "314:1360-1368, 1986).", "More precisely, IDDM is the result of the destruction of beta cells mediated by CD4+and CD8+cells and the function of antigen presenting cells (APC) (Frque F., Hadzija M., et al.", ", Proc.", "Natl.", "Acad.", "Sci.", ", USA, 91:3936-3940, 1994).", "NOD (non-obese diabetic) mice develop the classical picture of diabetes which is completely identical to IDDM in people (Makino S., et al.", ", Expl.", "Anim.", "29: 1 (1980)).", "Furthermore, chemical diabetes caused by alloxan in mice also develops the picture of diabetes with all the accompanying symptoms identical to the human form of diabetes of Type I (Dunn J. S., et al.", ", Lancet II: 384-387, 1943).", "The purpose of the therapy of diabetes is the normalization of the following parameters: the concentration of glucose in blood, the concentration of lipids, and the absence of glucose and acetone in urine.", "The therapy is carried out in six ways: by diabetic nourishment, by physical activity, by education and self-control, by oral hypoglycemic medicaments, by exogenous insulin or by transplantation of pancreas or islets.", "Insulin Insulin is a polypeptide hormone consisting of the 51 amino acid.", "It is made of two polypeptide chains which are mutually connected by two disulfide bridges, and it is created in β cells of Islets of Langerhans of the pancreas, from where it is secreted into blood.", "Only 25% of the total insulin from the pancreas enters blood stream daily, and most of it remains stored in p cells (Huton J. C., Diabetologia 32: 271-281).", "The main stimulus to secretion of insulin is glucose which concurrently stimulates the synthesis of insulin as well.", "Except for it, secretion is also stimulated by: particular ingredients of food (amino acids, higher fatty acids) some gastrointestinal hormones (secretin, cholecystokinin, gastrin .", "The secretion curve has a biphasic shape: a sudden short-term increase of secretion is followed by a slower, long-term secretion.", "The first phase corresponds to the release of the stored insulin, and in the second phase, new synthesized insulin is released.", "Secretion of Insulin is Inhibited by: somatostatin catecholamines through β adrenergic receptors hypothalamus through n. splanchnicus.", "Insulin acts through insulin receptors which are located on the outer side of cell membranes of target organs (liver, muscles, fat tissue), so that, bound through the so-called “second messenger”", "in that way, it causes changes of cell enzymes (activation and inhibition) and the change of the cell membrane.", "Because of that, the action of insulin depends, beside on its concentration, also on the number and the affinity of insulin receptors.", "Physiological Effects of Insulin: by induction of enzymes, it stimulates the deposit of glucose in the liver in form of glycogens, inhibiting glycolysis as well it increases the synthesis of triglycerides and obstructs glucogenesis in the liver it increases the transport of glucose and amino acids into the muscle tissue where th synthesis of proteins and glycogens is increased it inhibits the hydrolysis of the stored triglycerides in the fat tissue, and activates lipase which decomposes lipoproteins.", "With the lack of insulin in diabetic patients, the synthesis of proteins is reduced, and a large quantity of free amino acids is available for glucogenesis.", "Besides, free fatty acids pass into blood in an increased extent, and from it to the liver, where they are decomposed to acetyl-CoA by β-oxidation, and the increased quantity of acetyl-CoA cannot be used in the citric acid cycle, but acetoacetic acid is made, which leads to ketogenesis.", "Oral Hypoglycemic Substances Oral antidiabetics are a support to secretion of endogenic insulin, or they prevent the decomposition of glucose, and they are effective in the presence of at least a small quantity of insulin.", "By the chemical structure, they are classified as preparations of sulfonylurea, biguanides and inhibitors of glycosidase (Pickup J C, Blackwell, 1997).", "Derivatives Of Sulfonylurea Historical subclassification: preparations of “the first generation”: tolbutamide, chlorpropamide preparations of “the second generation”: glybenchlamyde, glyquidon, glychlaside, glypiside Activity Mechanism For achieving of the hypoglycemic effect of the derivatives of sulfonylurea, at least partly preserved production of insulin in β cells is necessary.", "On the molecular level, the basic mechanism of activity is the inhibition of the so-called K + channels dependent on ATP.", "The blockade of ATP dependent K + channels consequentially causes the increased entering of Ca 2+ into the cell which mobilizes the secretory granules with insulin according towards the cell membrane and stimulates their exocytosis.", "Pharmacokinetics After the peroral application, faster resorption of all the preparations is achieved, which mostly bind themselves to plasma proteins.", "They are mostly excreted by urine, and some through bile as well.", "Side Effects They cause side effects in form of gastrointestinal disturbances (anorexia, nausea), skin reactions (urticarias), cholestatic jaundice, and intolerance to alcohol.", "Concurrent taking with some medicaments (e.g. sulfonamides, phenylbutazone, salidylates .", "), which repress the preparations from the connection with plasma proteins, can strengthen the hypoglycemic action of the preparations of sulfonylurea (Scheen A. J., et al.", ", Drugs 55:225-236, 1998).", "Biguanides Among biguanides we include: metformin, buformin and fenformin.", "Activity Mechanisms The mechanism of the activity of biguanides is not quite known yet.", "It is supposed that those medicaments reduce the concentration of glucose in blood of diabetic patients, probably by increasing the degree of utilization of glucose in peripheral tissues, by stimulation of glycolysis, by inhibition of glyconeogenesis in liver, by reduction of the intestinal resorption of glucose, and by lowering the level of glucagon in the plasma (Pickup J. C., Blackwell, 1997;", "Scheen A. J., et al.", ", Drugs 55: 225-236, 1998).", "Pharmacokinetics After the resorption in the digestive tract, biguanides are bound to plasma proteins.", "They are excreted by kidneys, and the halftime of semi-elimination is different depending on the preparation.", "Side Effects Side effects in form of gastrointestinal disturbances (nausea, vomiting, metal taste in the mouth) are frequent, which can also be the first sign of the most difficult side effect—lactoacidosis (disturbance of metabolism with the increase of the concentration of lactic acid in tissues and in blood).", "Lactoacidosis is more common in patients with the damaged function of kidneys and liver, in pregnancy, in increased consumption of alcohol.", "They have a favourable therapeutic effect in obese patients.", "They are also used in combination with preparations of sulfonylurea and inhibitors of α-glucosidases.", "α-Glucosidase Inhibitors Among inhibitors of α-glucosidase, we include: acarbose, myglytol, voglybose, castanospermin Acarbose Activity Mechanism Acarbose is pseudotetrasaccharide of microbiological origin from the genus Actinomices .", "It is a competitive and reversible inhibitor of intestinal enzymes of glucoamylase, saccharase, maltase, dextrinase, as well as pancreatic amylase.", "Structurally, it is similar to oligosaccharides which develop by hydrolysis of starch.", "An acarbose molecule consists of acarviosin and a unit of glucose mutually connected by α1-14 glycoside bonds.", "For the inhibition of α-glycosidase, the secondary group of acarviosins is responsible, which prevents the carboxyl group of enzymes to protonate the oxygen of the glycoside bond.", "Thus, due to the reversible process, the hydrolysis of oligosaccharides is postponed, which reduces absorption of glucose in blood after a meal (Clissold S. P., et al.", ", Drugs 35: 214-243, 1989).", "Pharmacokinetics After oral application, acarbose is absorbed only 1 to 4%.", "It metabolizes with the help of amylases of the digestive tract and intestinal bacteria.", "Antidiabetic Effect Acarbose in patients with NIDDM prevents hyperglycemia after a meal, reduces the concentration of glucose in blood and reduces the need for insulin.", "Contraindications Acarbose is contraindicated in patients with disturbances of digestion and absorption, with chronical diseases of liver, and during pregnancy and lactation.", "Development of Neuropathy in Diabetes Neuropathy is a frequent late complication in diabetes which affects somatic and autonomous nerves.", "Neuropathy appears in a certain percentage in diabetes Type I and in Type II (Greene D. A., et al.", ", Diabetes Care 15: 1902-6, 1992).", "Peripheral nerve abnormalities in people or in animal model of diabetes are manifested by reduction of the conductibility of nerves, by shortening of axons, by reduction of the number of axons, connected with metabolic disturbance, including the changes of calcium signal.", "Studies carried out until now showed that the disturbance of homeostasis of Ions of calcium is a widespread occurrence in IDDM and NIDDM.", "The same change was noticed both, in people suffering from diabetes, and in animal models of diabetes, and that is the increase of the concentrations of Ca 2+ ions in cytosol.", "The increase of the concentration of calcium ions aids to the process of the natural way of dying (apoptosis) of nerve cells, but that process was shown in many other experimental models too.", "The latest researches showed that “the factors from the serum”", "have an important role in pathogenesis of diabetic neuropathy in patients with Type I diabetes.", "By incubation of β cells of islets of Langerhans in conditions of the culture of tissues, when the serum of patients with Type I diabetes was added to the medium, apoptosis with β cells L.o. was connected with the increase of the concentration of-calcium ions of L type.", "It was also shown that neuroblastoma cells showed a reduced growth, the increase of entering of Ca 2+ ions, that is, the increased apoptosis, if they were exposed to the serum of patients suffering from Type I diabetes with neuropathies.", "The complement of an independent, Ca dependent induction of apoptosis of nerve cells improves the appearance of autoimmune immunoglobulins in diabetes on nerve axons.", "Zeolites are a group of natural minerals of the basic structure of AlO 4 and SiO 4 tetrahedrons mutually bound by an oxygen atom.", "Their basic characteristic is that, by their structure, they are microcrystals with micropores of various diameters and of various composition dependant on origin.", "Until today, the known zeolites of natural, that is, artificial origin, are applied in industry;", "but also in medicine.", "EXAMPLES OF REALIZATION Natural clinoptilolite showed unfavourable chemical-ionic composition for this invention, due to a too low concentration of Ca 2+ ions.", "As such, it had to be submitted to the process of semi-synthesis whereby the replacement of Na + ions with Ca 2+ ions happens.", "Working Example 1 Semi-synthetic Clinoptilolite Clinoptilolite is heated to 500° C. for the purpose of eliminating of molecular water.", "By a screw conveyor, clinoptilolite treated in that way is in a controlled way and continuously brought to a high temperature vessel from which it is transported under pressure into a jet of compressed air with the speed of 510 m/s, so that particles of minerals accelerated in that way collide with an obstacle prepared for that purpose in order to be fragmented to the necessary size.", "Particles created in that way are submitted to ionic exchange in the liquid phase enriched with Ca 2+ ions by standard procedure (Breck D W, J.Chem Educ 41:678, 1964;", "Fedorov V A, et all, Zh Fiz Khim.", "38: 1248, 1964;", "Wolf F, Foertig H. Kolloid Z.-Z.", "Polymere 206: 48, 1965;", "Sherry H S, Adv.", "Chem Ser, 101: 350, 1971;", "Brooke N M, Rees L V C, Adv Chem Ser.", "101: 405, 1971;", "Barrer R M, Klinowski J Phil Trans.", "285: 637, 1977).", "Thus prepared clinoptilolite is further used for preparation of the mineral-herbal preparation from the invention.", "In order that the Ca—form of clinoptilolite be achieved, after the temperature treatment, clinoptilolite was submitted to semi-synthetic exchange in the liquid phase and enriched with Ca 2+ ions.", "An ionic exchange follows: Working Example 2 Ionic Exchange Na-clinoptilolite +Ca 2+ (L)⇄ Ca-clinoptilolite +2Na + Clinoptilolite SM prepared in that way was used in preparation of the mineral-herbal preparation from this invention.", "The composition of the mineral-herbal preparation includes also: Working Example 3 Extract of Nettle Root, Stalk and Leaf URTICAE RADIX, HERBA ET FLOS URTICA DIOICA L .", ", URTICACEAE—NETTLE The extract from the Urtica dioica is obtained in by standard procedure, shortly: the mixture of the nettle root, stalk and leaf, was cut into tiny pieces, and from plant substance cut in that way extract was made in 3-8 days.", "Extraction can be done with water, with acetone, ethanol, 70% of ethanol and 30% of water, alcohol.", "Solvent was removed from the extract by evaporator R-114, Buchi, Switzerland, and by a further procedure, the extract of nettle was frozen in liquid nitrogen and then lyophilized by standard procedure.", "The obtained powder had all the characteristics described below and used in popular medicine.", "Nettle contains many minerals, calcium 490 mg %, iron 10 mg % (most than all the self-grown vegetables), a little sulfur, sodium and potassium, quite a lot of organic acids, vitamin C, depending on the season, up to 174 mg %, vitamin B1, histamine, chlorophyll, some enzymes.", "People have used nettle against anemia for a long time, which is also justified for anemias arisen due to the lack of iron.", "That is in accordance with the popular belief that nettle has a positive effect on strengthening of defense powers of the organism.", "Tea from leaves of nettle stimulates the excretion of urine.", "For example, two week treatment increases the volume of urine and reduces the body mass.", "Taking nettle has a particularly favorable effect on diseases of prostate in older men.", "It stimulates the circulation and eliminates uric acid from the organism, so that it is recommended in case of arthritis and gout.", "It can help in healing of diseases of liver and bile.", "Popular medicine uses fresh nettle leaves.", "It prepares juice by pressing of fresh plant, then, tea, syrup and extract, and hot compresses are put on burns, cuts and inflamed hemorrhoids.", "Nettle preparations are applied externally in case of seborrhea and balding.", "Nettle seeds are given in case of tuberculosis and for treatment of lungs after bronchitis.", "It was recently discovered that the plant contains about 5.9 mg % of proteins.", "Working Example 4 ASTRAGALUS ASTRAGALI RADIX ASTRAGALUS MEMBRANACEUS (FISCH.", "EX LINK) Fabaceae The extract from the Astragalus membranaceus is obtained in by standard procedure, shortly: the root of astragalus is cut to tiny pieces, and from the plant mass cut like that, extract is made in 3-8 days.", "Extraction can be done with water, with acetone, ethanol, 70% of ethanol and 30% of water, alcohol.", "Solvent was removed from the extract by evaporation (Evaporator R-114 Buchi, Switzerland), the extract of astragalus was frozen in liquid nitrogen and lyophilized by standard procedure.", "The obtained powder had all the characteristics described below and used in popular medicine.", "Thus, astragalus is spread in the territory of eastern Mediterranean and southern and western Asia.", "The medicinal part of the plant are underground parts.", "Astragalus contains many active substances: Astragalosides from I to VII.", "Triterpene glycosides, flavonol glycosides, saponin.", "Tests on animals showed its immunostimulatory effect and protection of organism from the effect of toxins.", "It helps in illnesses of peripheral blood vessels and improves the peripheral circulation.", "Its antioxidant effect was proved, that is, soothing of the consequences of the liver cirrhosis.", "In popular medicine it is used for strengthening of organism, as an immunostimulator, diuretic, and in case of infections of upper respiratory tract.", "Notify extracts was mixed in adequate mass ratio.", "Working Example 5 Preparation of B Complex The basic source of B complex vitamines is preparation rich in proteins, hydrocarbons, lipids, minerals, vitamins and essential amino acids.", "As the basic source of vitamins of B complex was used from inactive Saccharomyces sp.", "a preparation rich in proteins, hydrocarbons, lipids, minerals, vitamins and essential amino acids.", "This preparation was used as the basic source of vitamins of B complex in the mineral-herbal preparation Except for the stated, the mineral-herbal preparation can, but need not contain other minerals too, like mordenite, montmorilonite.", "Working Example 6 Analyzed by Atomic Absorption Spectroscopy SM clinoptilolite, as fine dust, is chemically treated and analyzed by atomic absorption spectroscopy.", "The quality and quantity of the invention is analyzed by diffractometry by x-rays on the Siemens 500° D. diffractometer of CuK α radiation, in the region 20=4-80°.", "Working Example 7 Thermogravimetry Thermogravimetry of SM clinoptilolite, that is, the differential thermogravimetry was analyzed by the use of the device TA4000 Mettro-Toledo.", "Working Example 8 Size of Particles The size of particles of SM clinoptilolite is determined by the method of diffusion of the laser light on the device Mastersize XLB, Malven.", "Working Example 9 Experimental Diabetes Testings were made on two models of experimental diabetes.", "Experimental diabetes was caused by alloxan in CBA mice, in the dose of 75 mg/kg of body weight.", "After the appearance of the symptoms of diabetes, 3 mice were kept in each cage.", "NOD mice, which developed all the symptoms of diabetes, were taken in the experiment.", "In toxicological tests, the mineral-herbal preparation was admixed to the standard food for laboratory mice.", "This invention will now be shown with particular examples showing that, in case of diabetes, a syndrome is in question, and that, for a successful treatment of diabetes mellitus type I or II, it is not sufficient to apply the known medicine which has only the characteristic of a strong hypoglycemic effectiveness, but that the mineral-herbal preparation from the invention should be applied which helps the disturbed metabolism its entirety.", "Working, Example 10 Determining of the Level of Apoptosis The level of apoptosis was determined after cutting of the sample of the nerve in cryostat.", "To cut samples of 4 82 m, propidium iodine was added and the sample was analyzed under fluorescent microscope.", "Working Example 11 Presence of IgG on Nerves The presence of IgG on nerves was ascertained by colouring of nerves with antibodies on IgG conjugated with fluorescein.", "Working Examples 12 Diabetic animals which were receiving the mineral-herbal preparation with this composition: SM clinoptilolite of 50 mg, mordenite 15 mg, montmorilonite 15 mg, extract of astragalus 5 mg, extract of nettle 11.5 mg, B1 10 μg, B2 8 μg, B6 1.25 μg, B12 0.3 μg, with all the symptoms of diabetes, with 17.3 mM/L glucose in blood.", "Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured.", "During the first three days of the application of the mineral-herbal preparation, animals did not show the reduction of the symptoms of diabetes.", "The same was repeated in the next three days.", "The concentration of glucose in blood was above 18 mM/L, and the animals drank more than 30 ml of water daily.", "Further therapy also did not have a positive effect on symptoms of diabetes in CBA and NOD mice either.", "Here should particularly be pointed out that no significant developments were made for the purpose of reducing the level of glucose, and that the symptoms of diabetes were also not reduced.", "During the test, mice were moderately active.", "Working Example 13 Diabetic animals which were receiving the mineral-herbal preparation with this composition: clinoptilolite 180 mg, mordenite 27.5 mg, montmorilonite 22 mg, extract of astragalus 6 mg, extract of nettle 12 mg, B1 25 μg, B2 18 μg, B6 2.5 μg, B12 0.7 μg, with all the symptoms of diabetes, with 14.5 mM/L.", "glucose in blood.", "Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured.", "During the first three days of the application of the mineral-herbal preparation, animals did not considerably reduce the symptoms of diabetes.", "The same was repeated in the next three days, so that the volume of water drunk and the urine excreted was reduced by 50%.", "In the test of burdening with glucose, the mineral-herbal preparation did not show a hypoglycemic effect, but the curve of the assimilation of glucose was considerably more favourable in relation to untreated control mice, which is valid both for CBA diabetic mice, and for NOD diabetic mice.", "During the further therapy, through 6 months, the symptoms of diabetes were not eliminated, but they were considerably reduced.", "One should particularly point out here that for the purpose of reduction of glucose no significant developments were made, but that the symptoms of diabetes were considerably reduced.", "During the test, mice were moderately active.", "Working Example 14 Diabetic animals which were receiving the mineral-herbal preparation with this composition: clinoptilolite 600 mg, mordenite 60 mg, montmorilonite 80 mg, extract of astragalus 11 mg, extract of nettle 9 mg, B1 3.5 μg, B2 2 μg, B6 2.5 μg, B12 2.75 μg, with all the symptoms of diabetes, with 14.7 mM/L glucose in blood.", "Mice were placed in metabolic cages and during 6 days the quantity of water drunk, the quantity of food eaten, of urine and feces excreted were measured.", "During the first three days of the application of the mineral-herbal preparation, there was a reduction of the symptoms of diabetes.", "The quantity of water drunk and food eaten in the group of CBA diabetic mice and in the group of NOD diabetic mice was reduced considerably.", "The volume of urine excreted was also reduced.", "In the next three days, the symptoms of diabetes returned.", "The concentration of glucose in blood was over 15 mM/L, and animals drank about 25 ml of water daily.", "The further therapy did not have a positive effect on the symptoms of diabetes either.", "One should particularly point out here that for the purpose of reduction of glucose no significant developments were made, and also that the symptoms of diabetes were not reduced either.", "During the test, mice were moderately active.", "Pharmacological Data Toxicology No harmful toxic effects were ascertained if the animals were receiving the mineral-herbal preparation during 6 months, that is, one year.", "The effect of this mineral-herbal preparation on the concentration of glucose in blood was tested in control and diabetic CBA and NOD mice.", "The results were compared with the group of diabetic CBA mice which were not receiving the preparation.", "After 14 days, the animals were receiving the invention through a probe in the quantity of 50 to 400 mg on 25 grams of the body weight.", "On the 14 th day, the zero sample of blood (25 μL) was taken from the tail vein.", "Mice were submitted to the test of assimilation of glucose (OGTT).", "During the next 2 hours, in certain periods of time, blood samples were taken and the concentration of glucose in them was determined.", "The results are shown in FIGS. 3 and 4 .", "The concentration of glucose in diabetic CBA mice (10 mice per group) which were not receiving the preparation averagely amounted to 12.8±3.2 mM/L (FIG.", "3 ).", "After 10, that is, 30 minutes from injecting of glucose, the concentration of glucose in peripheral blood of mice was strongly increased to values above 20 mml/L.", "During the next hour and a half, the concentration of glucose started to decrease, but it did not reach the values of the beginning concentration of glucose in blood (FIG.", "3 ).", "However, in diabetic mice which were receiving the mineral-herbal preparation through 14 days, the concentration of glucose was considerably increased after injecting, just as it did in untreated mice.", "But in the following hour and a half, animals assimilated glucose more strongly and the concentration of glucose was approximately the same as the initial values of about 15 mmol/L (FIG.", "3 ).", "in NOD mice (n=12) with active autoimmune process and all the symptoms of diabetes, the concentration of glucose in blood was about 17 mmol/L.", "After probing of glucose in those mice, no increase of glucose in blood during the next 10, that is, 30 minutes was noticed.", "But in NOD mice treated with the invention, the increase of the concentration of glucose in blood during the first 30 minutes after probing was noticed, and a slight decrease of the concentration of glucose, during the next hour and a half, towards the initial values (FIG.", "4 ).", "Results of these tests showed that the mineral-herbal preparation does not have a direct hypoglycemic effect, but that the concentration of glucose still returns to the starting hyperglycemic value.", "However, it proved that the mineral-herbal preparation has a considerable effect on other symptoms of diabetes (FIGS.", "5 and 6 ).", "Thus diabetic mice which received the invention by probe through 6 days drank considerably less water during the experiment in comparison with the initial values (p<0.001) (FIG.", "5 ).", "Diabetic CBA mice which were receiving the mineral-herbal preparation for 6 days considerably reduced the volume of excreted urine during the experiment (p<0.001) (FIG.", "6 ).", "During 6 months, mice were receiving the mineral-herbal preparation together with food each day.", "From Table 4 is evident that the mineral-herbal preparation did not show any harmful effect because the weight of control, healthy mice was not reduced, but grew during the experiment.", "Thus, the body weight averagely increased from the beginning 35 grams to 40 grams.", "But, in the group of CBA mice, there was a decrease of the body weight to about 26 grams during the experiment (Table 1).", "During the whole experiment, there was no increase of the body weight from the initial values in the group of diabetic mice (Table 1), which is a usual occurrence in case of diabetes.", "During the experiment, a decrease of the body weight was noticed in the group of diabetic NOD mice (Table 2).", "In the beginning of the experiment, the body weight was about 35grams, while in the end of the experiment the mice weighed approximately 30 grams (table 2) During 6 months of examining of the effect of the invention on diabetic state, the level of the concentration of calcium ions (Ca 2+ ) in the serum of control and diabetic mice (Table 3) was monitored.", "The concentration of Ca 2+ ions during the 6 months did not change in blood of diabetic CBA mice which were receiving the invention each day.", "But in the group of diabetic CBA mice, after the duration of illness of 6 months, there was a statistically significant decrease (p<0.05) of the concentration of Ca 2+ ions in the serum (Table 3).", "In the group of control, non-diabetic NOD mice, the body weight was constantly increasing during the experiment (Table 2).", "Similar results were also shown by mice with spontaneous diabetes (Table 4).", "The concentration of Ca 2+ ions did not change in the group of diabetic NOD mice which were receiving the invention each day.", "A considerable reduction of the concentration of calcium ions was measured in the group of diabetic NOD mice which were not receiving the mineral-herbal preparation (p<0.05) (Table 4).", "Animals from particular groups were sacrificed after 7, 90, that is 180 days.", "By patho-histological treatment, the level of neuropathy of the digestive tract (Tables 5 and 6) was ascertained.", "After 180 days, diabetic CBA mice which were not receiving the mineral-herbal preparation, developed diabetic neuropathy in 100% of cases.", "However, in diabetic CBA mice which were receiving the mineral-herbal preparation each day, the diabetic neuropathy was not observed (Table 5).", "The same experiment was also made with diabetic NOD mice.", "Diabetic NOD mice develop diabetic neuropathy in 100% of cases during 6 months (Table 6).", "Diabetic NOD mice, which were receiving the mineral-herbal preparation during 180 days did not develop diabetic neuropathy (Table 7).", "In order to check the extent of the damage of nerves, that is, to examine the presence of apoptotic bodies, on the day of sacrificing, samples of n. ischiadicus were taken from mice.", "The obtained results show that long-term diabetes has a considerable effect on the increase of the number of apoptotic bodies.", "In the group of diabetic mice, the number of apoptotic bodies was about 65% (FIG.", "7 ).", "In controls (healthy mice), the number of apoptotic bodies was about 7%.", "Diabetic mice treated with the invention did not show a considerable increase of the number of apoptotic bodies in n. ischiadicus (FIG.", "8 ).", "By immunofluorescent colouring, the presence of antibodies (IgG) on nervus ischiadicus was tested.", "Diabetic mice which developed all the symptoms of diabetic neuropathy showed a strong presence of IgG in n. ischiadicus (FIG.", "7 ).", "Contrary to that, mice which were receiving the invention for 6 months did not have auto-anti-bodies on nerve axons of n. ischiadicus (FIG.", "8 ).", "The percentage of apoptotic bodies is statistically considerably smaller in the group of mice (CBA and NOD) treated by the invention (Table 7 and 8).", "Further, after colouring with anti IgG conjugated with fluorescein, the percentage of positive neurons in the group of mice treated by the invention was between 6 and 9% (Table 7 and 8).", "In this patent application, specific realizations of this invention were shown.", "Those acquainted with this field know that various equations of this invention are possible.", "It should be pointed out that al such realizations of this invention are comprised by the range of patent claims that follow." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates generally to the field of oil and gas well services. More specifically, the present invention relates to an apparatus that orients a tool into a desired position while the tool is in a deviated wellbore. 2. Description of Related Art When downhole tools, including perforating guns, are used in slanted or deviated wellbores it is often important that the tool be in a specific radial orientation. For example, orienting perforating guns in deviated wells enables the well operator to aim the shaped charges of the perforating gun at specific radial locations along the circumference of the wellbore. This is desired because the potential oil and gas producing zones of each specific well could exist at any radial position or region along the wellbore circumference. Based on the presence and location of these potential producing zones adjacent a deviated well, a well operator can discern a perforating gun orientation whose resulting perforations result in maximum hydrocarbon production. Information relevant to attempts to orient downhole tools, including perforating guns, can be found in U.S. Pat. Nos. 4,410,051, 4,438,810, 5,040,619, 5,211,714, 4,637,478, 5,603,379, 5,964,294. However, each of these references suffers from one or more of the following disadvantages. Some of the devices described in these references position a perforating gun such that only downward perforations are possible, others obstruct the path of the some of the shaped charges located on the perforating gun, while others are attached to the exterior of the perforating gun which can make handling of the tool inside of a wellbore more cumbersome. Daniel et al, U.S. Pat. No. 4,410,051 discloses a system for orienting a perforating gun to be used in wells having multiple tubing strings. The apparatus of Daniel et al. '051 consists of a plurality of subassemblies connected end to end. Situated in one of the subassemblies is an eccentric weight sub that contains a weight positioned asymmetric to the longitudinal axis of the housing. Connected to the bottom of the eccentric weight sub is the alignment joint sub which is used to align the bottom portion of the housing with outlets of the perforating gun. In Daniel et al. '051 the perforating gun section of the apparatus is disclosed as being below the eccentric weight sub. Wilkinson, U.S. Pat. No. 4,438,810 and Jordan et al., U.S. Pat. Nos. 5,040,619 and 5,211,714 also disclose the use of an eccentrically weighted sub attached to a perforating gun to rotate the perforating gun inside of a deviates wellbore. George, U.S. Pat. No. 4,637,478 involves a gravity oriented perforating gun for use in slanted wells comprised of one or more segments or subs, where each sub contains a center of gravity movement means which is a window that is cut out of the sub wall to alter the sub symmetry. Because it is asymmetric, the sub will rotate until the heavier portion of the sub circumference is below the lighter portion of the sub circumference. Henke et al., U.S. Pat. No. 5,603,379, involves an apparatus for connecting and orienting perforating guns in a deviated well bore. The orientation aspect of the device consists of a fin longitudinally connected to the body of the perforating gun that positions the gun off center in the casing so that gravity will position the gun body at the bottom of the casing. Because of the positioning aspect of Henke '379, the perforations are generally directed into a downward trajectory. Vann, U.S. Pat. Nos. 4,194,577 and 4,269,278 also disclose a perforating gun including longitudinal disposed fins on the gun outer circumference which act to direct the perforating charges in a downward pattern. Edwards et al., U.S. Pat. No. 5,964,294, discloses a downhole tool for use in a deviated well constructed to rotate in response to a moment applied at its axis. The tool includes ballast chambers filled with a flowable ballast material to produce a gravitational force for rotating the tool. The ballast chambers are formed on the inner diameter of the loading tube assembly. The flowable ballast material consists of a high density metal such as tungsten or depleted uranium. Alternative embodiments include a multiple segmented tool where each tool has offset centers to produce rotation of the tool. Therefore, there exists a need for a system that orients perforating guns in deviated wellbores where the shaped charges of the perforation gun can be directed in any radial orientation, a system that cooperates with a perforating gun having any shot pattern without affecting the shot pattern, and a system that is integral within the perforating gun. BRIEF SUMMARY OF THE INVENTION One embodiment of the present invention discloses a system and method for orienting downhole tools, including perforating guns, into a specified orientation, while the tool is inside of a deviated or slanted wellbore. The tool comprises a perforating gun having a substantially cylindrical gun body with an inner and an outer diameter. Disposed within the gun body is a gun tube also with an inner and an outer diameter. The gun tube contains at least one shaped charge. Attached to the outer surface of the gun tube is a weight. Each weight has apertures formed therethrough that are aligned with each shaped charge so that the shot performance of each shaped charge is not affected by the attached weight during detonation. The attached weight can be equal to or less than the length of the gun tube. A method of aligning a perforating gun in a deviated wellbore comprises adapting a weight for attachment to the outer surface of a gun tube having one or more shaped charges. Radial locations along the weight are identified that coincide with the location of each shaped charge. Apertures through the weight are formed at each radial location. The weight is attached to the outer surface of gun tube such that the apertures are coaxially aligned with each shaped charge. The gun tube is placed into the gun body of a perforating gun, and the perforating gun containing the gun tube is inserted into the deviated section of a wellbore. When the rotation of the gun body caused by the Earth's gravitational force upon the eccentric weight has ceased, the shaped charges are ready to be detonated. The method also envisions receiving coordinates where perforations are desired within the wellbore. The weight is then strategically situated on the gun body such that rotation of the gun body caused by the Earth's gravitational force upon the weight orients the gun body so the shaped charges are aimed at the coordinates. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 illustrates a perspective view of a gun tube and eccentrically loaded weight of the Internal Oriented Perforating System. FIG. 2 depicts a cross-sectional view of the Internal Oriented Perforating System. DETAILED DESCRIPTION OF THE INVENTION With reference to the drawing herein, an internal oriented perforating system according to one embodiment of the present invention is shown in FIG. 1 . The perspective view of FIG. 1 illustrates a gun tube 20 for use in a perforating system that incorporates one or more shaped charges 30 situated within the gun tube 20 . The gun tube 20 is suitable for use in perforating subterranean wells, it is appreciated that one reasonably skilled in the art can produce a gun tube having shaped charges with ordinary effort and without undue experimentation. As is well known in the art, the gun tube 20 is a generally cylindrical elongated body with a range of lengths and diameters. While the length of the gun tube 20 of the present invention ranges from 4 feet to 28 feet, the advantages of the present invention can be enjoyed with a gun tube 20 of any length. The preferred diameters of the gun tube 20 are 2¾″ and 2″, however gun tubes of any diameter can be practiced as a part of this invention. The perforating system of the present invention involves the gun tube 20 disposed within a gun body 21 , the gun body 21 having a slightly longer length than the gun tube 20 located therein. Often times individual perforating guns are connected end to end to create a perforating gun assembly. Because perforation operations can involve perforating a section of wellbore of less than 10 feet to over 10,000 feet, the length of the perforating gun assembly will vary accordingly. To accommodate these situations, and as is well known, the perforating gun of the present invention can comprise a single gun tube 20 with a gun body 21 , or multiple sections of the gun tube 20 and gun body 21 . A swiveling connection (not shown) is used to connect multiple perforating guns into the perforating gun assembly. It is important that the connections allow the gun body 21 to rotate freely with respect to the connection and other gun bodies included in the perforating assembly. Attached to the outer circumference of the gun tube 20 is a weight 40 that produces an eccentric loading about the axis of the gun tube 20 . While it is preferred that the weight 40 be secured to the gun tube 20 by fasteners 42 , such as rivets, bolts, pins, tabs, or screws, other attachments could also include welding. The weight 40 , as can be seen in FIG. 2, is generally semi-circular in cross section and includes apertures 41 formed at various locations along its body. The apertures 41 should be formed to be aligned with openings on the gun tube 20 where the shaped charge openings 31 and the shaped charge back 32 are located. While the weight 40 can be formed from any material, the material should have a high density and be machinable. As such, the preferred materials include carbon steel, depleted uranium, tungsten, steel alloys, copper alloys, stainless steel, and lead. As can be seen from the figures, the shaped charge back 32 and the detonation cord 33 can extend past the outer circumference of the gun tube 20 . To accommodate for these protrusions, the apertures 41 proximate to the shaped charge back 32 are created to tailor the weight 40 for a better fit onto the gun tube 20 , while the apertures 41 proximate to the shaped charge openings 31 act to prevent the weight 40 from obstructing the discharge perforating jet produced by detonation of the shaped charges 30 . As seen in FIG. 2, the weight 40 attaches along a portion of the circumference of the gun tube 20 which produces an asymmetric structure. As is well known, when the perforating gun is in a generally horizontal position and the center of gravity of the weight 40 is directly below the gun tube center 22 , the gravitational forces acting on the weight 40 on both sides of the gun tube centerline 23 are equal. When the gravitational forces about the gun tube centerline 23 are equal, gravity cannot cause rotation of the gun tube 20 . However, when the center of gravity of the weight 40 is not directly below the gun tube center 22 , the gravitational forces about the gun tube centerline 23 are not equal. The resulting imbalance will urge the weight 40 downward until the center of gravity of the weight 40 is directly below the gun tube center 22 , i.e. or until the gravitational forces applied to the weight 40 on either side of the gun tube center 22 are equal. When this occurs the weight 40 is at its “low point.” Attaching the weight 40 to the gun tube 20 outer circumference, instead of some other location along the gun tube 20 radius, maximizes the gravitational moment arm experienced by the eccentrically weighted gun tube 20 . Maximizing the moment arm produces a gun tube 20 more responsive to eccentrically applied gravitational forces. A gun tube 20 being more responsive to eccentrically applied gravitational forces will rotate quicker when these forces are applied. Additionally, a more responsive gun tube 20 is more likely to rotate until the weight 40 is in the low point without prematurely stopping and leaving the center of gravity of the weight 40 at a point higher than the low point. For reasons to be discussed below, it is important that the weight 40 be in the low point before the shaped charges 30 of the perforating gun are detonated. In operation, one or more perforating guns of the present invention are assembled and inserted into a well that is to be perforated. Inserting the present invention into a wellbore can be done with a conventional wireline, in conjunction with a tractor sub, or can be tubing conveyed. When the perforating gun reaches a deviated or slanted portion of the well, the gravitational forces will act upon the eccentric weight 40 until the weight 40 is in the low position. Prior to assembly the wellbore technical personnel evaluate how the shaped charges 30 should be aimed based on potential producing zones adjacent the wellbore. The gun tube 20 orientation during detonation is dependent upon how the shaped charges should be aimed during the perforation sequence. Once the desired orientation of the gun tube 20 during detonation is finalized, it can then be determined where the weight 40 should be attached such that its eccentrically loaded mass can rotate the gun tube 20 into the desired orientation. Before the weight 40 is attached to the gun tube 20 apertures 41 are formed through the weight 40 so that the weight 40 will not cover the shaped charge opening 31 or the shaped charge back 32 . As the perforating gun is put into position for detonating the shaped charges, it will be cycled up and down inside of the wellbore to provide some mechanical force impulses to the gun tube 20 . These impulses can shake the gun tube 20 and further ensure that the weight 40 has rotated into a low position. Cycling the perforation gun may be more important in instances where the deviated section of the wellbore exceeds 15° to 20° from horizontal, or if some foreign matter has become stuck between the gun tube 20 and the gun body 21 , thereby retarding rotation of the gun tube 20 inside of the gun body 21 . After completing the cycling process, the well operator positions the perforation gun to the depth inside of the wellbore where perforations are to be made. When the perforation gun is at the proper depth, the shaped charges 30 will be detonated thereby perforating the wellbore. Alternative embodiments of eccentrically loading a perforating gun include introducing a semi-cylindrical gun tube that is asymmetric about its longitudinal axis. The asymmetry of the gun tube in and of itself eccentrically weights the perforating gun so that when non-vertical the perforating gun will rotate in response to gravitational pulls on the eccentric loading. Another alternative embodiment involves creating longitudinal recesses along sections of the gun tube 21 and adding metal rods or bars into those recesses. The presence of the metal rods or bars will produce an asymmetry that also can rotate the perforating gun. However, the recesses should be located in the same hemispherical section of the gun tube 21 to produce an eccentrically loaded situation. A yet additional alternative embodiment exists where asymmetry of the gun body 20 is developed by securing the gun tube 21 inside of the gun body 20 at or proximate to the inner circumference gun body 20 and not coaxial within the gun body 20 . The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes in the details of procedures for accomplishing the desired results. Such as the utilization of non-metallic materials in the construction of the weight 40 . Additionally, the device and method described herein is suitable for use in any type of well, such as a water well, and is not restricted to use in hydrocarbon producing wells. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.
One embodiment of the present invention discloses a system and method for orienting perforating guns inside of slanted or deviated wellbores. The invention involves adding a weight inside of the guns to gravitate the gun to a specified orientation. The weight is situated on the outer circumference of the gun tube and within the inner diameter of the gun body. The invention is capable of orienting the gun in any radial position without affecting the shot performance of any of the shaped charges.
Identify the most important claim in the given context and summarize it
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The invention relates generally to the field of oil and gas well services.", "More specifically, the present invention relates to an apparatus that orients a tool into a desired position while the tool is in a deviated wellbore.", "Description of Related Art When downhole tools, including perforating guns, are used in slanted or deviated wellbores it is often important that the tool be in a specific radial orientation.", "For example, orienting perforating guns in deviated wells enables the well operator to aim the shaped charges of the perforating gun at specific radial locations along the circumference of the wellbore.", "This is desired because the potential oil and gas producing zones of each specific well could exist at any radial position or region along the wellbore circumference.", "Based on the presence and location of these potential producing zones adjacent a deviated well, a well operator can discern a perforating gun orientation whose resulting perforations result in maximum hydrocarbon production.", "Information relevant to attempts to orient downhole tools, including perforating guns, can be found in U.S. Pat. Nos. 4,410,051, 4,438,810, 5,040,619, 5,211,714, 4,637,478, 5,603,379, 5,964,294.", "However, each of these references suffers from one or more of the following disadvantages.", "Some of the devices described in these references position a perforating gun such that only downward perforations are possible, others obstruct the path of the some of the shaped charges located on the perforating gun, while others are attached to the exterior of the perforating gun which can make handling of the tool inside of a wellbore more cumbersome.", "Daniel et al, U.S. Pat. No. 4,410,051 discloses a system for orienting a perforating gun to be used in wells having multiple tubing strings.", "The apparatus of Daniel et al.", "'051 consists of a plurality of subassemblies connected end to end.", "Situated in one of the subassemblies is an eccentric weight sub that contains a weight positioned asymmetric to the longitudinal axis of the housing.", "Connected to the bottom of the eccentric weight sub is the alignment joint sub which is used to align the bottom portion of the housing with outlets of the perforating gun.", "In Daniel et al.", "'051 the perforating gun section of the apparatus is disclosed as being below the eccentric weight sub.", "Wilkinson, U.S. Pat. No. 4,438,810 and Jordan et al.", ", U.S. Pat. Nos. 5,040,619 and 5,211,714 also disclose the use of an eccentrically weighted sub attached to a perforating gun to rotate the perforating gun inside of a deviates wellbore.", "George, U.S. Pat. No. 4,637,478 involves a gravity oriented perforating gun for use in slanted wells comprised of one or more segments or subs, where each sub contains a center of gravity movement means which is a window that is cut out of the sub wall to alter the sub symmetry.", "Because it is asymmetric, the sub will rotate until the heavier portion of the sub circumference is below the lighter portion of the sub circumference.", "Henke et al.", ", U.S. Pat. No. 5,603,379, involves an apparatus for connecting and orienting perforating guns in a deviated well bore.", "The orientation aspect of the device consists of a fin longitudinally connected to the body of the perforating gun that positions the gun off center in the casing so that gravity will position the gun body at the bottom of the casing.", "Because of the positioning aspect of Henke '379, the perforations are generally directed into a downward trajectory.", "Vann, U.S. Pat. Nos. 4,194,577 and 4,269,278 also disclose a perforating gun including longitudinal disposed fins on the gun outer circumference which act to direct the perforating charges in a downward pattern.", "Edwards et al.", ", U.S. Pat. No. 5,964,294, discloses a downhole tool for use in a deviated well constructed to rotate in response to a moment applied at its axis.", "The tool includes ballast chambers filled with a flowable ballast material to produce a gravitational force for rotating the tool.", "The ballast chambers are formed on the inner diameter of the loading tube assembly.", "The flowable ballast material consists of a high density metal such as tungsten or depleted uranium.", "Alternative embodiments include a multiple segmented tool where each tool has offset centers to produce rotation of the tool.", "Therefore, there exists a need for a system that orients perforating guns in deviated wellbores where the shaped charges of the perforation gun can be directed in any radial orientation, a system that cooperates with a perforating gun having any shot pattern without affecting the shot pattern, and a system that is integral within the perforating gun.", "BRIEF SUMMARY OF THE INVENTION One embodiment of the present invention discloses a system and method for orienting downhole tools, including perforating guns, into a specified orientation, while the tool is inside of a deviated or slanted wellbore.", "The tool comprises a perforating gun having a substantially cylindrical gun body with an inner and an outer diameter.", "Disposed within the gun body is a gun tube also with an inner and an outer diameter.", "The gun tube contains at least one shaped charge.", "Attached to the outer surface of the gun tube is a weight.", "Each weight has apertures formed therethrough that are aligned with each shaped charge so that the shot performance of each shaped charge is not affected by the attached weight during detonation.", "The attached weight can be equal to or less than the length of the gun tube.", "A method of aligning a perforating gun in a deviated wellbore comprises adapting a weight for attachment to the outer surface of a gun tube having one or more shaped charges.", "Radial locations along the weight are identified that coincide with the location of each shaped charge.", "Apertures through the weight are formed at each radial location.", "The weight is attached to the outer surface of gun tube such that the apertures are coaxially aligned with each shaped charge.", "The gun tube is placed into the gun body of a perforating gun, and the perforating gun containing the gun tube is inserted into the deviated section of a wellbore.", "When the rotation of the gun body caused by the Earth's gravitational force upon the eccentric weight has ceased, the shaped charges are ready to be detonated.", "The method also envisions receiving coordinates where perforations are desired within the wellbore.", "The weight is then strategically situated on the gun body such that rotation of the gun body caused by the Earth's gravitational force upon the weight orients the gun body so the shaped charges are aimed at the coordinates.", "BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 illustrates a perspective view of a gun tube and eccentrically loaded weight of the Internal Oriented Perforating System.", "FIG. 2 depicts a cross-sectional view of the Internal Oriented Perforating System.", "DETAILED DESCRIPTION OF THE INVENTION With reference to the drawing herein, an internal oriented perforating system according to one embodiment of the present invention is shown in FIG. 1 .", "The perspective view of FIG. 1 illustrates a gun tube 20 for use in a perforating system that incorporates one or more shaped charges 30 situated within the gun tube 20 .", "The gun tube 20 is suitable for use in perforating subterranean wells, it is appreciated that one reasonably skilled in the art can produce a gun tube having shaped charges with ordinary effort and without undue experimentation.", "As is well known in the art, the gun tube 20 is a generally cylindrical elongated body with a range of lengths and diameters.", "While the length of the gun tube 20 of the present invention ranges from 4 feet to 28 feet, the advantages of the present invention can be enjoyed with a gun tube 20 of any length.", "The preferred diameters of the gun tube 20 are 2¾″ and 2″, however gun tubes of any diameter can be practiced as a part of this invention.", "The perforating system of the present invention involves the gun tube 20 disposed within a gun body 21 , the gun body 21 having a slightly longer length than the gun tube 20 located therein.", "Often times individual perforating guns are connected end to end to create a perforating gun assembly.", "Because perforation operations can involve perforating a section of wellbore of less than 10 feet to over 10,000 feet, the length of the perforating gun assembly will vary accordingly.", "To accommodate these situations, and as is well known, the perforating gun of the present invention can comprise a single gun tube 20 with a gun body 21 , or multiple sections of the gun tube 20 and gun body 21 .", "A swiveling connection (not shown) is used to connect multiple perforating guns into the perforating gun assembly.", "It is important that the connections allow the gun body 21 to rotate freely with respect to the connection and other gun bodies included in the perforating assembly.", "Attached to the outer circumference of the gun tube 20 is a weight 40 that produces an eccentric loading about the axis of the gun tube 20 .", "While it is preferred that the weight 40 be secured to the gun tube 20 by fasteners 42 , such as rivets, bolts, pins, tabs, or screws, other attachments could also include welding.", "The weight 40 , as can be seen in FIG. 2, is generally semi-circular in cross section and includes apertures 41 formed at various locations along its body.", "The apertures 41 should be formed to be aligned with openings on the gun tube 20 where the shaped charge openings 31 and the shaped charge back 32 are located.", "While the weight 40 can be formed from any material, the material should have a high density and be machinable.", "As such, the preferred materials include carbon steel, depleted uranium, tungsten, steel alloys, copper alloys, stainless steel, and lead.", "As can be seen from the figures, the shaped charge back 32 and the detonation cord 33 can extend past the outer circumference of the gun tube 20 .", "To accommodate for these protrusions, the apertures 41 proximate to the shaped charge back 32 are created to tailor the weight 40 for a better fit onto the gun tube 20 , while the apertures 41 proximate to the shaped charge openings 31 act to prevent the weight 40 from obstructing the discharge perforating jet produced by detonation of the shaped charges 30 .", "As seen in FIG. 2, the weight 40 attaches along a portion of the circumference of the gun tube 20 which produces an asymmetric structure.", "As is well known, when the perforating gun is in a generally horizontal position and the center of gravity of the weight 40 is directly below the gun tube center 22 , the gravitational forces acting on the weight 40 on both sides of the gun tube centerline 23 are equal.", "When the gravitational forces about the gun tube centerline 23 are equal, gravity cannot cause rotation of the gun tube 20 .", "However, when the center of gravity of the weight 40 is not directly below the gun tube center 22 , the gravitational forces about the gun tube centerline 23 are not equal.", "The resulting imbalance will urge the weight 40 downward until the center of gravity of the weight 40 is directly below the gun tube center 22 , i.e. or until the gravitational forces applied to the weight 40 on either side of the gun tube center 22 are equal.", "When this occurs the weight 40 is at its “low point.”", "Attaching the weight 40 to the gun tube 20 outer circumference, instead of some other location along the gun tube 20 radius, maximizes the gravitational moment arm experienced by the eccentrically weighted gun tube 20 .", "Maximizing the moment arm produces a gun tube 20 more responsive to eccentrically applied gravitational forces.", "A gun tube 20 being more responsive to eccentrically applied gravitational forces will rotate quicker when these forces are applied.", "Additionally, a more responsive gun tube 20 is more likely to rotate until the weight 40 is in the low point without prematurely stopping and leaving the center of gravity of the weight 40 at a point higher than the low point.", "For reasons to be discussed below, it is important that the weight 40 be in the low point before the shaped charges 30 of the perforating gun are detonated.", "In operation, one or more perforating guns of the present invention are assembled and inserted into a well that is to be perforated.", "Inserting the present invention into a wellbore can be done with a conventional wireline, in conjunction with a tractor sub, or can be tubing conveyed.", "When the perforating gun reaches a deviated or slanted portion of the well, the gravitational forces will act upon the eccentric weight 40 until the weight 40 is in the low position.", "Prior to assembly the wellbore technical personnel evaluate how the shaped charges 30 should be aimed based on potential producing zones adjacent the wellbore.", "The gun tube 20 orientation during detonation is dependent upon how the shaped charges should be aimed during the perforation sequence.", "Once the desired orientation of the gun tube 20 during detonation is finalized, it can then be determined where the weight 40 should be attached such that its eccentrically loaded mass can rotate the gun tube 20 into the desired orientation.", "Before the weight 40 is attached to the gun tube 20 apertures 41 are formed through the weight 40 so that the weight 40 will not cover the shaped charge opening 31 or the shaped charge back 32 .", "As the perforating gun is put into position for detonating the shaped charges, it will be cycled up and down inside of the wellbore to provide some mechanical force impulses to the gun tube 20 .", "These impulses can shake the gun tube 20 and further ensure that the weight 40 has rotated into a low position.", "Cycling the perforation gun may be more important in instances where the deviated section of the wellbore exceeds 15° to 20° from horizontal, or if some foreign matter has become stuck between the gun tube 20 and the gun body 21 , thereby retarding rotation of the gun tube 20 inside of the gun body 21 .", "After completing the cycling process, the well operator positions the perforation gun to the depth inside of the wellbore where perforations are to be made.", "When the perforation gun is at the proper depth, the shaped charges 30 will be detonated thereby perforating the wellbore.", "Alternative embodiments of eccentrically loading a perforating gun include introducing a semi-cylindrical gun tube that is asymmetric about its longitudinal axis.", "The asymmetry of the gun tube in and of itself eccentrically weights the perforating gun so that when non-vertical the perforating gun will rotate in response to gravitational pulls on the eccentric loading.", "Another alternative embodiment involves creating longitudinal recesses along sections of the gun tube 21 and adding metal rods or bars into those recesses.", "The presence of the metal rods or bars will produce an asymmetry that also can rotate the perforating gun.", "However, the recesses should be located in the same hemispherical section of the gun tube 21 to produce an eccentrically loaded situation.", "A yet additional alternative embodiment exists where asymmetry of the gun body 20 is developed by securing the gun tube 21 inside of the gun body 20 at or proximate to the inner circumference gun body 20 and not coaxial within the gun body 20 .", "The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein.", "While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes in the details of procedures for accomplishing the desired results.", "Such as the utilization of non-metallic materials in the construction of the weight 40 .", "Additionally, the device and method described herein is suitable for use in any type of well, such as a water well, and is not restricted to use in hydrocarbon producing wells.", "These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims." ]
This application is a continuation-in-part of U.S. patent application Ser. No. 11/907,808, filed Oct. 17, 2007, now U.S. Pat. No. 7,885,214 which is assigned to the same assignee as the present application, and which claims the benefit of priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Ser. No. 60/852,891, filed on Oct. 17, 2006. BACKGROUND OF THE INVENTION In an orthogonal frequency division multiplexing (OFDMA)-based cellular radio interface, such as described in patent application Ser. No. 11/907,808, by Sassan Ahmadi and Hujun Yin, filed on Oct. 12, 2007, which is herein incorporated by reference in its entirety, propagation of radio signals in large cell sizes and/or lower frequency bands can lead to larger delay spread and consequently can cause inter-symbol interference (ISI) effects in the received signals. In the OFDM-based systems, the effects of ISI are mitigated by the cyclic prefix that is added to the beginning of the OFDM symbols. The larger the delay spread, the longer the cyclic prefix should be used to alleviate the ISI effects. BRIEF DESCRIPTION OF THE DRAWING The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings in which: FIG. 1 is a schematic illustration of a wireless network according to an embodiment of the present invention; FIG. 2 is a schematic illustration of an apparatus for use in a wireless network according to an embodiment of the present invention; FIG. 3 is a schematic illustration of a frame structure according to an embodiment of the present invention; FIG. 4 is a schematic illustration of a super-frame structure according to an embodiment of the present invention; FIG. 5 is a schematic illustration of a super-frame structure according to an embodiment of the present invention; FIGS. 6 , 6 A, and 6 B are schematic illustrations of super-frame structure according to an embodiment of the present invention; FIG. 7 is a schematic illustration of a super-frame structure having a new preamble multiplexed with a legacy preamble according to an embodiment of the present invention; FIG. 8 is a schematic illustration of a super-frame structure having a supplemental preamble multiplexed with a legacy preamble, where the new preamble may be obscured from legacy terminals, according to an embodiment of the present invention; FIG. 9 is a schematic illustration of a frame structure partitioned in the time and/or frequency domain according to an embodiment of the present invention; FIG. 10 is a schematic illustration of a frame structure in FDD duplex mode according to an embodiment of the present invention; FIGS. 11-13 are schematic illustrations of frame structures, according to embodiments of the present invention; FIG. 14 is a table of OFDMA parameters according to embodiments of the present invention; and FIG. 15 is a flow chart of a method according to an embodiment of the present invention. It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element. Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements. Moreover, some of the blocks depicted in the drawings may be combined into a single function. DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention. Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices. In addition, the term “plurality” may be used throughout the specification to describe two or more components, devices, elements, parameters and the like. While the following detailed description may describe various embodiments of the present invention in relation to wireless networks utilizing orthogonal frequency division multiplexing (OFDM) modulation, the embodiments of present invention are not limited thereto and, for example, may be implemented using other modulation and/or coding schemes where suitably applicable. Further, while example embodiments are described herein in relation to wireless metropolitan area networks (WMANs), the invention is not limited thereto and can be applied to other types of wireless networks where similar advantages may be obtained. Such networks specifically include, but are not limited to, wireless local area networks (WLANs), wireless personal area networks (WPANs), and/or wireless wide area networks (WWANs). The following inventive embodiments may be used in a variety of applications including transmitters and receivers of a radio system, although the present invention is not limited in this respect. Radio systems specifically included within the scope of the present invention include, but are not limited to, network interface cards (NICs), network adaptors, mobile stations, base stations, access points (APs), gateways, bridges, hubs and cellular radiotelephones. Further, the radio systems within the scope of the invention may include cellular radiotelephone systems, satellite systems, personal communication systems (PCS), two-way radio systems, two-way pagers, personal computers (PCs) and related peripherals, personal digital assistants (PDAs), personal computing accessories and all existing and future arising systems which may be related in nature and to which the principles of the inventive embodiments could be suitably applied. Reference is made to FIG. 1 , which schematically illustrates a wireless network 100 according to an embodiment of the present invention. Wireless network 100 may include provider network (PN) 120 , a base station (BS) 118 , and one or more subscriber or other stations 110 , 112 , 114 , and/or 116 , which may be for example mobile or fixed subscriber stations. In some embodiments, base station 118 , for example, in WLANs, may be referred to as an access point (AP), terminal, and/or node, and subscriber stations 110 , 112 , 114 , and/or 116 may be referred to as a station (STA), terminal, and/or node. However, the terms base station and subscriber station are used merely as an example throughout this specification and their denotation in this respect is in no way intended to limit the inventive embodiments to any particular type of network or protocols. Wireless network 100 may facilitate wireless access between each of subscriber stations 110 , 112 , 114 , and/or 116 and PN 120 . For example, wireless network 100 may be configured to use one or more protocols specified in by the Institute of Electrical and Electronics Engineers (IEEE) 802.11™ standards (“IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification. 1999 Edition”, reaffirmed Jun. 12, 2003), such as IEEE 802.11a™-1999; IEEE 802.11b™-1999/Cor1-2001; IEEE 802.11g™-2003; and/or IEEE 802.11n™, in the IEEE 802.16™ standards (“IEEE Standard for Local and Metropolitan Area Networks—Part 16: Air Interface for Fixed Broadband Wireless Access System”, Oct. 1, 2004), such as IEEE 802.16-2004/Cor1-2005 or IEEE Std 802.16-2009, which may herein be referred to as the “IEEE Std 802.16-2009” or “WiMAX” standards, and/or in the IEEE 802.15.1™ standards (“IEEE Standard for Local and Metropolitan Area Networks—Specific Requirements. Part 15.1: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs™)”, Jun. 14, 2005), although the invention is not limited in this respect and other standards may be used. In some embodiments, attributes, compatibility, and/or functionality of wireless network 100 and components thereof may be defined according to, for example, the IEEE 802.16 standards (e.g., which may be referred to as a worldwide interoperability for microwave access (WiMAX)). Alternatively or in addition, wireless network 100 may use devices and/or protocols that may be compatible with a 3 rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) cellular network or any protocols for WPANs or WWANs. Embodiments of the invention may enable the next generation of mobile WiMAX systems (e.g., based on IEEE 802.16m standard) to efficiently support substantially high mobility and low latency applications, such as, for example, Voice-over-Internet Protocol (VoIP), interactive gaming over the air-interface, deployment in larger cell-sizes or lower frequency bands, and/or “multi-hop” relay operations, while enabling backward compatible operations and integration with reference standards (e.g., the legacy mobile WiMAX systems based on IEEE Std 802.16-2009). In some embodiments, base station 118 may manage and/or control wireless communications among subscriber stations 110 , 112 , 114 , and/or 116 and between subscriber stations 110 , 112 , 114 , and/or 116 and provider network 120 . Subscriber stations 110 , 112 , 114 , and/or 116 may, in turn, facilitate various service connections of other devices (not shown) to wireless network 100 via a private or public local area network (LAN), although the embodiments are not limited in this respect. Reference is made to FIG. 2 , which schematically illustrates an apparatus 130 for use in a wireless network according to an embodiment of the invention. For example, apparatus 130 may be a terminal, device, or node (e.g., one of subscriber stations 110 , 112 , 114 , and/or 116 , base station 118 , and/or provider network 120 , described in FIG. 1 ) for communicating with other terminals, devices, or nodes, in a wireless network (e.g., wireless network 100 , described in FIG. 1 ). Apparatus 130 may include a controller or processing circuit 150 including logic (e.g., including hard circuitry, processor and software, or a combination thereof) to determine the false frame detection rate and/or adjust the sensitivity of frame detection as described in one or more embodiments of the invention. In some embodiments, apparatus 130 may include a radio frequency (RF) interface 140 and/or a medium access controller (MAC)/baseband processor circuit 150 . In one embodiment, RF interface 140 may include a component or combination of components adapted for transmitting and/or receiving single carrier or multi-carrier modulated signals (e.g., including complementary code keying (CCK) and/or orthogonal frequency division multiplexing (OFDM) symbols) although the inventive embodiments are not limited to any specific over-the-air interface or modulation scheme. RF interface 140 may include, for example, a receiver 142 , a transmitter 144 and/or a frequency synthesizer 146 . Interface 140 may include bias controls, a crystal oscillator and/or one or more antennas 148 and/or 149 . In another embodiment, RF interface 140 may use external voltage-controlled oscillators (VCOs), surface acoustic wave filters, intermediate frequency (IF) filters and/or RF filters, as desired. Due to the variety of potential RF interface designs an expansive description thereof is omitted. Processing circuit 150 may communicate with RF interface 140 to process receive and/or transmit signals and may include, for example, an analog-to-digital converter 152 for down converting received signals, a digital-to-analog converter 154 for up converting signals for transmission. Further, processor circuit 150 may include a baseband or physical layer (PHY) processing circuit 156 for PHY link layer processing of respective receive/transmit signals. Processing circuit 150 may include, for example, a processing circuit 159 for medium access control (MAC)/data link layer processing. Processing circuit 150 may include a memory controller 158 for communicating with processing circuit 159 and/or a base station management entity 160 , for example, via interfaces 155 . In some embodiments of the present invention, PHY processing circuit 156 may include a frame construction and/or detection module, in combination with additional circuitry such as a buffer memory, to construct and/or deconstruct super-frames as in the embodiments previously described. Alternatively or in addition, MAC processing circuit 159 may share processing for certain of these functions or perform these processes independent of PHY processing circuit 156 . In some embodiments, MAC and PHY processing may be integrated into a single circuit if desired. Apparatus 130 may be, for example, a base station, an access point, a subscriber station, a device, a terminal, a node, a hybrid coordinator, a wireless router, a NIC and/or network adaptor for computing devices, a mobile station or other device suitable to implement the inventive methods, protocols and/or architectures described herein. Accordingly, functions and/or specific configurations of apparatus 130 described herein, may be included or omitted in various embodiments of apparatus 130 , as suitably desired. In some embodiments, apparatus 130 may be configured to be compatible with protocols and frequencies associated one or more of the IEEE 802.11, 802.15 and/or 802.16 standards for WLANs, WPANs and/or broadband wireless networks, cited herein, although the embodiments are not limited in this respect. Embodiments of apparatus 130 may be implemented using single input single output (SISO) architectures. However, as shown in FIG. 2 , certain implementations may include multiple antennas (e.g., antennas 148 and 149 ) for transmission and/or reception using adaptive antenna techniques for beamforming or spatial division multiple access (SDMA) and/or using multiple input multiple output (MIMO) communication techniques. The components and features of station 130 may be implemented using any combination of discrete circuitry, application specific integrated circuits (ASICs), logic gates and/or single chip architectures. Further, the features of apparatus 130 may be implemented using microcontrollers, programmable logic arrays and/or microprocessors or any combination of the foregoing where suitably appropriate. It is noted that hardware, firmware and/or software elements may be collectively or individually referred to herein as “logic” or “circuit.” It should be appreciated that the example apparatus 130 shown in the block diagram of FIG. 2 may represent one functionally descriptive example of many potential implementations. Accordingly, division, omission or inclusion of block functions depicted in the accompanying figures does not infer that the hardware components, circuits, software and/or elements for implementing these functions would be necessarily be divided, omitted, or included in embodiments of the present invention. Reference is made to FIG. 3 , which schematically illustrates a frame 300 structure according to an embodiment of the present invention. Frame 300 (e.g., a radio frame) may be a portion of a transmitted and/or received communication in, for example, wireless network 100 . In some embodiments, frame 300 may describe a periodically repeating segment structure of a larger communication signal or stream. In some embodiments, repeating frame 300 may include substantially different information, for example, during substantially each separate transmission. Frame 300 may be defined and may include broadband wireless access technology according to, for example, the IEEE Std 802.16-2009 or mobile WiMAX profiles. According to the mobile WiMAX profiles, the duration of frame 300 or transmission time interval (TTI) may be, for example, approximately 5 ms. Other frame or radio frame sizes such as for example 2, 2.5, 4, 8, 10, 12, and 20 ms may be used as for example specified in the IEEE Std 802.16-2009 specification. In some embodiments, frame 300 may be transmitted and/or received, for example, according to a time division duplex (TDD) mode or scheme. Other time and/or frequency schemes may be used (e.g., such as a frequency division duplex (FDD) mode or scheme) according to embodiments of the invention. Frame 300 may include an integer number of OFDM symbols or other multiplexing symbols. The number of OFDM symbols per frame may be determined, for example, according to a choice of OFDM numerology (e.g., sub-carrier spacing, cyclic prefix length, sampling frequency, etc.). In some embodiments, OFDM numerologies may be determined, set, or obtained, for example, depending, on a bandwidth and sampling frequency (e.g., or an over-sampling factor according to the mobile WiMAX profiles). In various embodiments, substantially different OFDM numerologies may be used, which may result in substantially different number of OFDM symbols in frame 300 . In some embodiments, frame 300 may include idle symbols and/or idle time slots. In one embodiment, frame 300 may include one or more switching periods 302 and/or 304 , for example, for changing between a pre-designated downlink (DL) transmission 306 and a pre-designated uplink (UL) transmission 308 when a TDD duplex mode or scheme is used. In other embodiments, for example, when an FDD duplex scheme is used, since DL transmissions 306 and UL transmissions 308 may be sent substantially at the same or overlapping times (e.g., over different frequencies or network channels) frame 300 may include substantially few or no idle symbols, idle time slots, and/or switching periods 302 and/or 304 . In some embodiments, the TTI or the duration of frame 300 may be, for example, approximately 5 ms. A round trip time (RTT) (e.g., the time interval between two consecutive pre-scheduled DL transmissions 306 to a specific wireless node may be, for example, approximately 10 ms. Wireless networks (e.g., wireless network 100 ) having rapidly changing channel conditions and/or small coherence times (e.g., rapidly moving mobile stations or nodes, such as automobiles having vehicular speeds of, for example, in the excess of approximately 120 kilometers per hour (km/h)) may use mechanisms for supporting substantially high mobility in varying channel conditions. Embodiments of the invention may support wireless network 100 having substantially small round trip times, for example, to enable substantially fast-varying channel condition feedback between subscriber stations 110 , 112 , 114 , and/or 116 , such as a mobile station, and base station 118 . Other time durations may be used. The current IEEE Std 802.16-2009 specification standard frame structure may include restrictions, such as substantially long TTIs that are typically not suitable for supporting substantially fast feedback and low access latency (e.g., less than 10 ms), which may be used by, for example, emerging radio access technologies. Embodiments of the present invention may include or use a modified version of the frame 300 structure for supporting lower latency operations, while maintaining backward compatibility, for example, to the IEEE Std 802.16-2009 specification frame structure. Frame 300 structure may be used, for example, in the next generation of mobile WiMAX systems and devices (e.g., including the IEEE 802.16m standard). In some embodiments, frame 300 structure or portions thereof may be transparent to the legacy terminals (e.g., which operate according to mobile WiMAX profiles and IEEE Std 802.16-2009) and may be used only for communication between BSs, subscriber stations, and/or MSs that both operate based on the IEEE 802.16m standard. According to embodiments of the invention, wireless network 100 and components thereof, which may communicate using the new frame structure (e.g., described according to FIGS. 3-15 ), may be backward compatible with a reference network, which may communicate using a legacy frame structure (e.g., described according to the mobile WiMAX profiles and based on the IEEE Std 802.16-2009). In some embodiments, backward compatibility may include for example, that a legacy terminal (e.g., which may communicate using legacy and/or reference frame structures) may operate in a wireless network with no significant impact on the performance and operation of the terminal relative to a legacy network. In some embodiments, a new (e.g., a non-legacy) terminal or subscriber station using the new (e.g., a non-legacy) frame structure may operate in a legacy network with no significant impact on the performance and operation of the terminal relative to the wireless network. For example, the new terminal may be “backward compatible”. In some embodiments, wireless network 100 may support both legacy and new (e.g., a non-legacy) terminals, for example, at substantially the same time (e.g., where time division multiplexing of the new and legacy frames overlap in the same frame). In some embodiments, wireless network 100 may enable seamless communication, mobility, and handoff between legacy terminals and new terminals. When used herein, “new”, “evolved” or “updated,” and “next generation” are merely relative to “old”, “legacy” or “current”, etc. For example, a “new” standard may be a standard that is in use as of the date of the filing of this application, and a “legacy” system may be one that is in use both prior to the date of filing this application and for some time after the filing of this application; a “new” system is one implemented or developed after a “legacy” system, typically including improvements and updates. “New”, “evolved”, “updated”, etc. systems are often backward compatible such that they are usable with “old”, “legacy” or prior systems or standards. According to embodiments of the invention, the new frame structure may include new synchronization and broadcast channels to extend the capabilities of the IEEE Std 802.16-2009 by, for example, enhancing system acquisition and/or enhancing cell selection at low signal to interference+noise ratios (SINR). According to the IEEE Std 802.16-2009 a broadcast channel (e.g., and a DL channel descriptor and UL channel descriptor) are typically not located at a pre-defined location in a frame, the mobile stations have to decode the common control channel (e.g., MAP) for acquiring system configuration information. According to an embodiment of the present invention, the new frame structure may include for example a super-frame that includes an integer number of radio frames, which may include synchronization and/or broadcast information and/or messages, such as, system configuration information, which may simplify wireless network 100 operations and further reduce the overhead and acquisition latency of wireless network 100 . Reference is made to FIG. 4 , which schematically illustrates a super-frame 400 structure according to an embodiment of the present invention. In some embodiments, a transmission between terminals or nodes may include, for example, one or more super-frames 400 . Super-frame 400 may include or be partitioned into a fixed and/or pre-determined number of frames 410 . In other embodiments, the number of frames 410 in each of two or more of super-frames 400 may be different. The number of frames, M, 410 within a super-frame 400 (e.g., M, may be an integer, where M=2, 3, 4 . . .) may be a design parameter and may be specified in a standard specification and, for example, may be fixed for a particular profile and deployment. In some embodiments, the number of frames 410 within super-frame 400 may be determined by one or more factors, including but not limited to, for example, target system acquisition time, a maximum permissible distance between two consecutive preambles (e.g., synchronization channels), the minimum number of preambles that may be averaged during system acquisition for the detection of the preamble, and/or a maximum permissible distance between two consecutive broadcast channels (e.g., system configuration information or paging channels). In one embodiment, substantially each super-frame 400 may be partitioned into or include two or more (e.g., four (4)) frames 410 . Other numbers of partitions, divisions, or frames may be used. The length of each frame 410 may be for example approximately 5 ms, for example, for establishing backward compatibility with systems compliant with IEEE Std 802.16-2009. Other frame or radio frame lengths may be used. Each of frames 410 may be further partitioned or sub-divided into two or more (e.g., eight (8)) sub-frames 420 . Other numbers of divisions may be used. The length of sub-frame 420 may determine the TTI for terminals that may be compliant with the new standard and, for example, incorporate super-frame 400 and/or frame 410 structures. The beginning and end of each of the TTIs may be substantially aligned or synchronized with, for example, a sub-frame boundary. Each TTI may contain an integer number of sub-frames (e.g. typically one or two sub-frames). Each sub-frame 420 may be partitioned into or include a fixed number of OFDM symbols 430 . In one embodiment, each sub-frame 420 may be partitioned into or include, for example, six (6) OFDM symbols, so that the number of OFDM symbols 430 within a sub-frame (e.g., the length of sub-frame 420 ) may be compatible to resource block sizes (e.g., sub-channels) corresponding to various permutation schemes, for example, specified in the IEEE Std 802.16-2009. In other embodiments, there may be other or alternative numbers, lengths, sizes, and/or variations, of super-frames 400 , frames 410 , sub-frames 420 , and/or OFDM symbols 430 . The numbers used herein are presented for demonstrative purposes only. In another embodiment, the length of frames 410 (e.g., approximately 5 ms) and the number of OFDM symbols 430 (e.g., six (6)), may be set for establishing backward compatibility with IEEE Std 802.16-2009 compliant systems, devices, and/or transmissions. Permutation schemes, for example, defined according to current standard specifications, may include a number, for example, from one to six, slots for transmitting signals and/or resource blocks. The boundary of physical a resource block may, for example, be aligned with a sub-frame boundary. In some embodiments, each physical resource block may be substantially contained within a single sub-frame 420 . In other embodiments, each physical resource block may be substantially contained within two consecutive sub-frames. It may be appreciated by those skilled in the art that embodiments of the invention, for example, including, super-frame 400 structures, may be applied using either of the TDD and FDD duplexing schemes or modes. In the FDD duplex mode, each of the DL and UL transmissions may be communicated, for example, concurrently, on respective frequencies or channels. In the TDD duplex mode, each of the DL and UL transmissions may be communicated, for example, at substantially non-overlapping intervals (e.g., according to time division multiplexing (TDM) scheme) over substantially the same frequency or channel. In the TDD duplex mode of operation and within any frame 410 , sub-frames 420 may be configured to DL and UL transmissions (e.g., DL transmission 306 and UL transmission 308 ) for example statically in each deployment. The DL and UL transmissions may be separated by idle times and/or idle symbols for switching between DL and UL transmissions (e.g., during switching periods 302 and/or 304 ). In one embodiment of the invention, “legacy zones” and “new zones” may include periods, portions or zones, for example, of DL or UL transmission, specifically designed to substantially only communicate with legacy terminals or new terminals, respectively. In the TDD duplex mode of the IEEE Std 802.16-2009, each of DL transmission 306 and UL transmission 308 may be further partitioned into two or more permutation zones. In some embodiments, the number of contiguous OFDM or other symbols 430 in a frame 410 , may be referred to as, for example, a permutation zone (e.g., permutation zone 310 , described in reference to FIG. 3 ). The permutation zone may, for example, include a number of contiguous OFDM symbols (e.g., in DL and UL transmissions 306 and 308 , described in reference to FIG. 3 ) that use substantially the same permutation (e.g., partially used sub-channel (PUSC) to distributed allocation of sub-carriers, Adaptive Modulation and Coding (AMC) for localized allocation of sub-carriers, etc.). According to an embodiment of the invention, a frame may include or may be partitioned into legacy zones and new zones (other terms may be used). In one embodiment, legacy terminals and new terminals may communicate using legacy zones and new zones, respectively. In some embodiments, new terminals may communicate using both legacy zones and new zones. Legacy terminals typically only communicate using legacy zones. In one embodiment, in the frame, each of DL transmissions may be further partitioned into two or more zones, for example, including a DL transmission legacy zones and a DL transmission new (e.g., non-legacy) zones and each of UL transmissions may be further partitioned into two or more zones, for example, including UL transmission legacy zones and UL transmission new (e.g., non-legacy) zones. Embodiments of the invention may provide a partitioning of frames into sub-frames (e.g., where the boundaries of transmission blocks or zones may be synchronized with the sub-frame boundaries). According to the IEEE Std 802.16-2009, the boundaries of transmission blocks or zones may start and end at any OFDM symbol within the boundary of a frame. According to embodiments of the invention, the new zones may use a new and more efficient resource allocation and feedback mechanism. The total number of OFDM symbols within a frame may vary depending on the OFDM numerology. In order to maintain backward compatibility with the legacy mobile WiMAX systems, the same frame size and OFDMA numerology (e.g., or OFDMA parameters) may be used for the IEEE 802.16m systems and the legacy mobile WiMAX systems. It may be appreciated by those skilled in the art that all permissible numerologies and/or frame sizes, for example, specified by the 802.16e-2005 standard, may be used in accordance with embodiments of the present invention. Embodiments of the invention may provide super-frame structures that may be compatible with legacy standards, such as, the IEEE Std 802.16-2009 and/or other standards. For example, the super-frame structure may include or may be compatible with a subset of features, for example, as specified in the mobile WiMAX profile (e.g., and may be backwards compatible with the mobile WiMAX profile). Embodiments of the invention may provide a super-frame structure, which may be partitioned into a number of frames that include, for example, one or more, legacy synchronization channel (e.g., a IEEE Std 802.16-2009 preamble), new synchronization channels (e.g., a IEEE 802.16m preamble), broadcast channel (BCH), medium access protocol (MAPs) or common control channel (CCCH) in the new and legacy zones corresponding to each frame or an integer number of frames. Reference is made to FIG. 5 , which schematically illustrates a super-frame 500 structure according to an embodiment of the present invention. In one embodiment, super-frame 500 may include a legacy preamble 502 , for example, which may be referred to as primary synchronization channel (PSCH). In some embodiments, super-frame 500 may include an additional or supplemental preamble 504 , for example, for improving system timing acquisition and cell selection for new terminals. Supplemental preamble 504 may, for example, be referred to as secondary synchronization channel (SSCH). The synchronization channels may include sequences, which may be used and/or deciphered by both base stations and mobile stations, for example, for acquiring frame timing and/or scheduling. In some embodiments, new preamble 504 may be effectively or partially transparent, unreadable, or undetectable to legacy terminals, while legacy preamble 502 may be detectable to both legacy and new terminals. In some embodiments, super-frame 500 may include a broadcast channel (BCH) 506 . The broadcast channel may contain information that may for example include system configuration information, paging, and/or other broadcast type information, and may be sent by a base station to all mobile stations in the network and/or surrounding area. As shown in FIG. 5 , supplementary or new preamble 504 (e.g., SSCH) may be located at a fixed position in new or legacy zones. In one embodiment of the present invention, for example, the new preamble 504 may be positioned at a fixed offset, which may be referred to as, for example, “SSCH_OFFSET”. The SSCH_OFFSET may be a measure of a location of the new preamble 504 , for example, relative to the location of the legacy preamble, for example, in every frame. In some embodiments, the legacy preamble in mobile WiMAX systems may be located in the first OFDM symbol of every frame (as shown in FIG. 9 ). The value of SSCH_OFFSET may be included and broadcasted as part of the system configuration information. In some embodiments, when new preamble 504 is detected by a mobile terminal, the SSCH_OFFSET may be used to locate the beginning of a frame. In one embodiment, when SSCH_OFFSET=0, there may be no legacy preamble 502 , which may indicate that the network does not support legacy terminals. In some embodiments, a new synchronization channel and the broadcast channel may span a minimum system bandwidth (BW). In some embodiments, the legacy synchronization channel typically spans the entire system BW, an example of which is shown in FIG. 9 . The region pre-designated for communicating new preamble 504 (e.g., via multiple sub-carriers) may be, for example, transparent and/or ignored by legacy terminals. A scheduler for downlink base station or terminal transmissions typically does not allocate user/system traffic/control/signaling in the region pre-designated for communicating new preamble 504 . In another embodiment of the present invention, for example, new preamble 504 may be located, for example, in the beginning of the new frame where the new frame may be located at a fixed offset relative to the legacy frame. In one embodiment, the fixed offset may be referred to as, for example, “FRAME_OFFSET”, and may be fixed within the frame timing. In some embodiments, the value of the FRAME_OFFSET may be set by a network operator or administrator (e.g., and not broadcast). The new mobile terminals may detect new preamble 504 , which may indicate the beginning of the new frame and, for example, other information channels relative to the beginning of the new frame (e.g., as shown in FIG. 6 ). For example, the timing or periodicity of BCH 506 may be substantially aligned with the timing or periodicity of super-frame 500 transmissions. In various embodiments, super-frame 500 may have substantially different structures, which may be distinguished, for example, based on the relative position of legacy preamble 502 and/or new preamble 504 in super-frame 500 , and/or other features or design considerations for the frame structure (e.g., such as a DL scan latency, physical layer overhead, and other information). It may be appreciated to those skilled in the art that although three options for the structure of super-frame 500 , including for example, options I, II, and III, may be described, various other structures and/or variations thereof may be used in accordance with embodiments of the present invention. The description that follows may include embodiments that may individually or collectively be referred to as Option I. Option I, and other “Options” presented herein are examples only, and are non-limiting. In some embodiments, new preamble 504 and/or BCH 506 may be positioned substantially at the beginning of each super-frame 500 , for example, in the first frame of each super-frame 500 in a communication stream. In such embodiments, legacy preamble 502 and new preamble 504 may be separately positioned (e.g., spaced or offset along the length of super-frame 500 ). In such embodiments, the impact or visibility of new preamble 504 to legacy terminals (e.g., which typically only detect legacy preamble 502 ) and operations thereof, such as, system acquisition, may be minimized. New preamble 504 may be periodically repeated at any desirable frequency, for example, substantially every frame. BCH 506 may contain system-configuration information, paging channels, and/or other broadcast information. In some embodiments, BCH 506 may be synchronized with super-frame 500 intervals and may appear every integer number of super-frames. In some embodiments, new terminals may use new preamble 504 (e.g., exclusively or additionally) to improve system timing acquisition and fast cell selection. For example, new preamble 504 may include cell identification (ID) information or codes and may be used for acquisition of frame timing by new terminals. For example, a cell ID code may include a concatenated base station group ID code, base station ID code, a sector ID code, and/or other codes or information, for example, to simplify the detection (e.g., execute a structured search) of the cell ID. According to embodiments of the invention described in reference to Option I, since new preamble 504 may be spaced from legacy preamble 502 , new preamble 504 may be minimally detectable by legacy terminals. In some embodiments, in order to minimize the physical layer overhead (layer 1 overhead), for example, which may be increased by using an OFDM symbol for transmitting new preamble 504 , new preamble 504 may be transmitted, for example, over a limited (e.g., minimal) bandwidth or time, or by using additional sub-carriers corresponding to the same OFDM symbol for scheduling user traffic, for example, as shown in FIG. 9 . The description that follows may include embodiments that may individually or collectively be referred to as Option II. Reference is made to FIG. 6 , which schematically illustrates a super-frame 600 structure according to an embodiment of the invention. In some embodiments for TDD duplex mode, super-frame 600 may be partitioned into, for example, four frames with pre-designated legacy periods, intervals or zones and new or non-legacy periods, intervals or zones. In one embodiment, legacy frame 610 may be further partitioned into sub-frames, including, for example, DL transmission legacy zones 612 and UL transmission legacy zones 616 . The new frame 620 may begin at a fixed offset (e.g., FRAME_OFFSET) relative to the beginning of the legacy frame. The value of the FRAME_OFFSET may be an integer number of sub-frames and may be determined based on the ratio of the lengths or time of the DL to UL transmissions (e.g., in TDD duplex mode). For example, when FRAME_OFFSET=T offset and T sub-frame denotes the length of the sub-frame and T f denotes the frame length the value of the minimum and maximum permissible values for T offset may be determined as follows: T offset <αT f 0≦α≦1: the fraction of frame allocated to DL Example: α=0.625 for DL:UL=5:3 nT sub-frame ≦αT f −T offset 1 ≦n< 7 T offset =mT sub-frame 0≦ m< (Number of DL Sub_Frames)− n In some embodiments, legacy terminals may communicate using legacy frames 610 and new terminals may communicate using new frames 620 and/or legacy frames 610 . According to embodiments of the invention, for example, in option III, the beginning of new frames 620 and legacy frames 610 may be offset by a fixed value, for example, by a frame offset 622 or an offset interval (e.g., a fixed duration of time and/or number of sub-frames). The relative positions of new frames 620 and legacy frames 610 according to one embodiment are depicted in FIG. 6 , for example, in TDD duplex mode. For example, in TDD duplex mode, legacy frame 610 structure may start with a DL transmission 612 and end with an UL transmission 616 . For example, new frame 610 structure may start with a DL transmission 614 , followed by a UL transmission 618 , and end with a DL transmission 614 . In some embodiments, each new frame 610 may contain a new preamble (e.g., SSCH), for example, in a sub-frame at the start or beginning of frame 610 . In other embodiments, each super-frame 600 may include a super-frame header (SFH) 624 , for example, in a sub-frame at the start or beginning of super-frame 600 . For example, SFH 624 may include a new preamble and a broadcast channel. For example, K and 6-K, K=1, 2, . . ., 6 may denote the number of OFDM symbols that are allocated to new preamble and broadcast channel, respectively. The number of OFDM symbols allocated to the new and legacy preambles may be as small as one OFDM symbol per channel. In one embodiment, the remainder of the OFDM symbols available in the SFH 624 sub-frame may be allocated, for example, for user traffic, control, and/or control and signaling information, which may minimize the system layerl overhead. SFH 624 may include a new preamble sequence and the broadcast information (e.g., including system configuration information and a paging channel). In some embodiments, legacy frames and new frames may have a fixed frame offset 622 , which may be configurable by the network operator. In some embodiments of the present invention, the legacy zone and new zone may be offset by a fixed number of sub-frames. The offset value may be substantially stable or fixed within a practical deployment. Due to the dynamic nature of network traffic in practice, in some frames, the legacy zone may be under-utilized while the new zone may be fully loaded or vice versa. In some embodiments, a pointer in a IEEE 802.16m common control channel may be designed and/or used, for example, to point to or indicate a sub-frame in the legacy zone that may be unused by legacy terminals. For example, when legacy zone and/or new zone partitions are fixed, the resources (e.g., sub-frames) may be dynamically allocated from frame to frame maximize the use of physical resources, which may otherwise be unused. The description that follows may include embodiments that may individually or collectively be referred to as Option III. Reference is made to FIG. 7 , which schematically illustrates a super-frame 700 structure having a new preamble 704 multiplexed with a legacy preamble 702 , according to an embodiment of the present invention. In some embodiments, a new preamble 704 may be multiplexed with a legacy preamble 702 , for example, every M frames (e.g., where M may be the number of frames within a super-frame 700 ). For example, the first OFDM symbol of the first frame 710 in super-frame 700 may include new preamble 704 and the M- 1 succeeding frames 710 in super-frame 700 may include legacy preamble 702 . In some embodiments, a common control channel (e.g., including DL and UL MAPS) and/or frame control header (FCH) 708 and a BCH 706 transmission may occur, for example, at super-frame 700 and frame 710 intervals, respectively. The acquisition of legacy preamble 702 (e.g., by legacy terminals) may break as a result of interruption in the reception of the periodic legacy preamble 702 . Since new preamble 704 and legacy preamble 702 may share physical resources, for example, and may be transmitted at substantially the same or overlapping times or locations along super-frame 700 , there may typically be no additional physical resource needed for including the new preamble 704 into a super-frame 700 structure. Additionally, in some embodiments, the position of new preamble 704 may be fixed within a periodic number (one or more) of frames 710 . In some embodiments, when new preamble 704 and legacy preamble 702 are code division multiplexed, for example, in substantially the same OFDM symbol, there is typically no substantial impact on the layerl overhead. In such embodiments, some legacy preambles 702 may be transmitted in succession and, for example, other legacy preambles 702 may be superimposed with new preamble 704 (e.g., according to multiplexing scheme discussed herein). In some embodiments, new preamble 704 may be multiplexed with legacy preamble 702 using, for example, a code division multiplexing (CDM) scheme. A CDM scheme may include code division multiplexing new preamble 704 and legacy preamble 702 , for example, substantially every M frames 710 , for example, as shown in FIG. 7 . In one embodiment, new preamble 704 and legacy preamble 702 sequences may be superimposed and transmitted (e.g., by a new base station or terminal) every M frames, for example, according to the following equation: y k =u k +x k u′ k where u k , u′ k , x k may denote the k th primary synchronization sequence, the k th new synchronization sequence, and the k th spreading function. Other (e.g., linear) combinations may be used. For example, the spreading function may include a set of robust spreading functions, which may substantially cover the new synchronization sequences. Other multiplexing schemes or combinations thereof may be used. In one embodiment, legacy preamble 702 and new preamble 704 may be, for example, code division multiplexed every fixed number (e.g., M=1, 2, 3 . . . ) frames. In such embodiments, legacy terminals may experience or include a small degradation in the energy of the legacy preamble every M frames. The new terminals may detect and extract new preamble 704 that may encroach or may be superimposed on legacy preamble 702 . As presented herein, new preamble may be referred to, for example, as “new preamble”, “new preamble”, “new synchronization channel”, “SSCH” and “secondary synchronization channel”, a new system, profile, and/or standard, may be referred to, for example, as an “evolved version” of the reference system standard. Reference is made to FIG. 8 , which schematically illustrates a super-frame 800 structure having a new preamble 804 multiplexed with a legacy preamble 802 , where legacy preamble 802 may be obscured from legacy terminals, according to an embodiment of the present invention. In some embodiments, the superposition of new preamble 804 on the legacy preamble 802 may, for example, increase interference levels or, for example, an interference over thermal 820 (IoT) value. The objective is to find the minimum Signal to Interference+Noise Ratio (SINR) that is required for proper detection of the legacy preamble or alternatively the maximum IoT that can be tolerated by the legacy terminals (this leads to the maximum power that can be used for the new preamble). In one embodiment of the present invention, a signal received at the s th sub-carrier, y s , may be calculated, for example, as shown in the equations that follow. In one embodiment, new preamble 804 associated with each new base station or relay station may be substantially different, for example, for enabling a mobile station to distinguish, detect, and/or select, different base stations or relay stations in a network. In some embodiments, since the received power 822 of new preamble 804 may be determined, or be directly proportional to, the IoT 820 , it may be desirable for the IoT 820 to be maximized, for example, to the extent that the minimum SINR level would allow the legacy terminals to correctly detect legacy preambles 802 . In some embodiments, an optimization of the IoT 820 value may be performed, for example, according to the equations that follow: y s = H s , k ⁢ u k + H s , k ⁢ χ k ⁢ u k ′ + w s + ∑ i ≠ k ⁢ H s , i ⁢ u i + ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′ SINR s = 20 ⁢ log 10 ⁢  H s , k ⁢ u k   H s , k ⁢ χ k ⁢ u k ′ + w s + ∑ i ≠ k ⁢ H s , i ⁢ u i + ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  SINR s ≥ 10 ⁢ ⁢ log 10 ⁢  H s , k ⁢ u k  2  H s , k ⁢ χ k ⁢ u k ′  2 +  w s  2 +  ∑ i ≠ k ⁢ H s , i ⁢ u i  2 +  ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  2 IoT =  H s , k ⁢ χ k ⁢ u k ′  2 SINR s min = 10 ⁢ ⁢ log 10 ⁢  H s , k ⁢ u k  2  w s  2 +  ∑ i ≠ k ⁢ H s , i ⁢ u i  2 +  ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  2 + IoT max where terms may be defined, for example, as follows: y s : Received Signal at sth Sub-Carrier u k : Legacy Preamble Sequence sent by kth BS H s,k : Multi-Path Channel Impulse Response u′ k : New Preamble Sequence sent by kth BS x k : kth Spreading Function w s : Received Noise at sth Sub-Carrier SINR s : Signal to Interference+Noise Ratios for Legacy Terminals ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′ ⁢ : Inter-Cell Interference due to New and Legacy Preambles Other criteria for the optimization of the IoT value may be used. In some embodiments, when legacy preambles 702 and 802 are code division multiplexed, transmitting new preamble 704 and 804 , respectively, may have substantially no or minimal effect on the physical layer overhead of the system in which they are transmitted. In such embodiments, superimposing new preamble 804 onto legacy preamble 802 respectively, may limit the received power 822 of new preamble 704 and may potentially interfere with or obscure system acquisitions of legacy preamble 802 by legacy terminals, for example, due to additional interference from new preambles transmitted by neighboring base stations or relay stations. The effect of additional interference may be minimized, for example, using robust preamble detection algorithms, for example, having minimal sensitivity to instantaneous degradation in the preamble power. It may be appreciated by those skilled in the art that each of three options for embodiments of the structure of a super-frame and/or partitions thereof, including for example, embodiments described in reference to each of options I, II, and III, may be applied to both TDD and FDD duplex schemes. The size and distribution of the new and legacy zones and their corresponding DL and UL transmissions and/or sub-frames, may depend, for example, on factors including but not limited to the distribution of the new and legacy terminals, network load and performance optimizations for new and legacy terminals. Reference is made to FIG. 10 , which schematically illustrates a frame 1000 structure in FDD duplex mode according to an embodiment of the present invention. Frame 1000 may include sub-frames 1030 . In some embodiments, super-frame 1000 may include a legacy preamble 1002 , a new preamble 1004 , and a BCH 1006 , which may be transmitted every integer number of super-frame transmissions. In one embodiment, legacy preamble 1002 , new preamble 1004 , and/or BCH 1006 may be positioned at the beginning of frame 1000 . According to embodiments of the invention, in the FDD duplex mode, DL transmissions 1016 and UL transmissions 1018 may occur substantially simultaneously, for example, at different frequencies (e.g., DL frequency F 1 1024 and UL frequency F 2 1026 , respectively). Reference is made to FIGS. 11-13 , which schematically illustrate frame structures 1100 , 1120 , 1200 , 1220 , 1300 , and 1320 and their respective sub-frames, 1110 , 1130 , 1210 , 1230 , 1310 , and 1330 , according to various embodiments of the present invention. In FIG. 11 , TDD frame 1100 is shown with a DL/UL ratio of 4:3 and FDD frame 1120 for 5, 10 or 20 MHz channel bandwidth with a cyclic prefix of ¼ of useful OFDM symbol length. The TDD frame 1100 may consist of seven sub-frames 1110 of six OFDM symbols each and FDD frame 1120 may have the same configuration as the TDD frame to maximize commonality or may consists of six sub-frames 1110 of six OFDM symbols and one sub-frame 1130 of seven OFDM symbols. As an example, for an OFDM symbol duration of 114.386 microseconds (Tb) and a CP length of ¼ Tb, the length of six-symbol sub-frames 110 and seven-symbol sub-frames 1130 are 0.6857 ms and 0.80 ms, respectively. In this case, the transmit-to-receive transmission gap (TTG) and receive-to-transmit transmission gap (RTG) are 139.988 microseconds and 60 microseconds, respectively. In FIG. 12 , TDD frame 1200 is shown with a DL/UL ratio of 3:2 and FDD frame 1220 for 7 MHz channel bandwidth with a CP of ¼ Tb. The TDD frame 1200 may consist of five six-symbol sub-frames 1210 and the FDD frame 1220 may have the same structure as the TDD frame to maximize commonality or may consist of four six-symbol sub-frames 1210 and one seven-symbol sub-frame 1230 . Assuming OFDM symbol duration of 160 microseconds and a CP length of ¼ Tb, the length of six-symbol sub-frame 1210 and seven-symbol sub-frame 1230 are 0.960 ms and 1.120 ms, respectively. The TTG and RTG are 140 microseconds and 60 microseconds, respectively. In FIG. 13 , TDD frame 1300 is shown with a DL/UL ratio of 4:2 and FDD frame 1320 for 8.75 MHz channel bandwidth with a CP of ¼ Tb. The TDD frame 1300 has four six-symbol sub-frames 1310 and two seven-symbol sub-frames 1330 and FDD frame 1320 has three six-symbol sub-frames 1310 and three seven-symbol sub-frame 1330 . Assuming OFDM symbol duration of 128 microseconds and a CP length of ¼ Tb the length of six-symbol sub-frame 1310 and seven-symbol sub-frame 1330 are 0.768 ms and 0.896 ms, respectively. The number of OFDM symbols in a sub-frame may be related to, for example, the length of each OFDM symbol and/or the cyclic prefix value. However, to simplify the implementation of the system, it is desirable that all sub-frames within a frame have the same size and consists of the same number of OFDM symbols. Embodiments of the invention may be used having any suitable OFDMA numerology. It may be appreciated by those skilled in the art that although a variety of parameters (e.g., duplex modes, cyclic prefix values, OFDMA numerologies, etc.) may be used according to embodiments described herein, suitable variations may be used, for example, as depicted in the variations of FIGS. 11-13 . Reference is made to FIG. 14 , which is a table of OFDMA parameters according to embodiments of the present invention. FIG. 14 lists parameters for a CP of ¼. The CP length of one quarter is equal to 22.85 microseconds (for bandwidths of 5, 10 or 20 MHz) which corresponds to a cell size of approximately 5 km. Therefore, a delay spread of up to 22.85 microseconds can be mitigated. Reference is made to FIG. 15 , which is a flow chart of a method according to an embodiment of the present invention. In operation 1500 , a processor in a terminal may partition each frame into two or more sub-frames. The frames (e.g., frames 410 described in reference to FIG. 4 , or other frames) may be backward compatible with a reference system profile and for example, defined according to a reference standard system (e.g., IEEE Std 802.16-2009 or mobile WiMAX profiles). Thus, as compared with the frames from which sub-frames are partitioned, the sub-frames (e.g., sub-frames 420 described in reference to FIG. 4 ) may be shorter and therefore processed and transmitted/received faster with smaller periodicity. Transmitting according to the sub-frame structure may provide over the air communications having a periodicity on the scale of several sub-frames instead of the relatively longer periodicity of several frames. In operation 1505 , a transmitter may transmit one or more sub-frames during a pre-designated downlink transmission (e.g., pre-designated DL transmissions 306 , described in reference to FIG. 3 ). In operation 1510 , the transmitter may transmit one or more sub-frames during a pre-designated uplink transmission (e.g., pre-designated UL transmissions 308 , described in reference to FIG. 3 ) In operation 1515 , the transmitter may transmit one of the plurality of sub-frames including a legacy preamble for communicating with a legacy terminal, for example, operating according to the reference system profile during a pre-designated legacy transmission period or zone (e.g., legacy zone 612 and/or 616 , described in reference to FIG. 6 ). In operation 1520 , the transmitter may transmit one of the plurality of sub-frames including a new preamble for communicating with a new (e.g., a non-legacy) terminal, for example, operating according to an evolved or newer version of the reference system standard, such as, the IEEE 802.16m standard, during a pre-designated new (e.g., a non-legacy) transmission period or zone (e.g., new zone 614 and/or 618 , described in reference to FIG. 6 ). In various embodiments, the first and second signals may be transmitted in a TDD duplex mode or an FDD duplex mode. In some embodiments, when the signals are transmitted in a TDD duplex mode, operations 1505 and 1510 may be executed over substantially different time intervals, or frame positions, such that the first and second signals may be transmitted separately. In other embodiments, when the when the signals are transmitted in an FDD duplex mode, operations 1505 and 1510 may be executed in substantially overlapping time periods, such that the first and second signals may be transmitted over substantially distinct frequencies and/or channels. In some embodiments, the sub-frames may be further partitioned into two or more (e.g., six) information-carrying, multiplexing, and/or OFDM symbols. In some embodiments, the first and second signals may include a legacy preamble for communicating with legacy terminals operating according to the reference system profile and a new preamble for communicating with a new (e.g., a non-legacy) terminal operating according to a second system standard and/or an evolved version of the reference system. In one embodiment, each of the first and second sub-frames may be pre-designated for communicating with one of a legacy terminal, a non-legacy terminal, or both a legacy and non-legacy terminal. For example, one of two or more sub-frames in operation 1510 may be pre-designated for communicating with both a legacy and a non-legacy terminal. In some embodiments, the beginning of the frames, which may be pre-designated for communicating with legacy terminals and non-legacy terminals, may be offset, for example, by a fixed number of sub-frames. In some embodiments, a super-frame may be defined. For example, the super-frame may include two or more frames (e.g., the frames described in operation 1500 ) that may be transmitted in succession. In one embodiment, the new preamble may be transmitted substantially once during the transmission of each super-frame. In one embodiment, the new preamble may be transmitted substantially once every frame. According to embodiments such as that of Option I described herein, the legacy preamble and the new preamble may be transmitted separately, for example, at a substantially fixed distance apart along the length of the frame. In one embodiment, a process may execute operations 1500 , 1505 , and 1510 and need not execute operations 1515 and 1520 . In another embodiment, a process may execute operations 1500 , 1515 , and 1520 and need not execute operations 1505 and 1510 . In yet another embodiment, a process may execute operations 1500 , 1505 , 1510 , 1515 , and 1520 . The process may execute other sequences, orders, and/or permutations of operations described herein. While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. Embodiments of the present invention may include other apparatuses for performing the operations herein. Such apparatuses may integrate the elements discussed, or may comprise alternative components to carry out the same purpose. It will be appreciated by skilled in the art that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
A frame structure for support of large delay spread deployment scenarios (e.g., cellular system operation in large cell sizes or low frequency bands) is generally presented. In this regard a method is introduced comprising partitioning a radio frame into a plurality of equal-sized (or non-equal-sized) sub-frames to simplify system implementation. Other embodiments are also disclosed and claimed.
Summarize the key points of the given document.
[ "This application is a continuation-in-part of U.S. patent application Ser.", "No. 11/907,808, filed Oct. 17, 2007, now U.S. Pat. No. 7,885,214 which is assigned to the same assignee as the present application, and which claims the benefit of priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Ser.", "No. 60/852,891, filed on Oct. 17, 2006.", "BACKGROUND OF THE INVENTION In an orthogonal frequency division multiplexing (OFDMA)-based cellular radio interface, such as described in patent application Ser.", "No. 11/907,808, by Sassan Ahmadi and Hujun Yin, filed on Oct. 12, 2007, which is herein incorporated by reference in its entirety, propagation of radio signals in large cell sizes and/or lower frequency bands can lead to larger delay spread and consequently can cause inter-symbol interference (ISI) effects in the received signals.", "In the OFDM-based systems, the effects of ISI are mitigated by the cyclic prefix that is added to the beginning of the OFDM symbols.", "The larger the delay spread, the longer the cyclic prefix should be used to alleviate the ISI effects.", "BRIEF DESCRIPTION OF THE DRAWING The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification.", "The invention, however, both as to organization and method of operation, together with objects, features and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanied drawings in which: FIG. 1 is a schematic illustration of a wireless network according to an embodiment of the present invention;", "FIG. 2 is a schematic illustration of an apparatus for use in a wireless network according to an embodiment of the present invention;", "FIG. 3 is a schematic illustration of a frame structure according to an embodiment of the present invention;", "FIG. 4 is a schematic illustration of a super-frame structure according to an embodiment of the present invention;", "FIG. 5 is a schematic illustration of a super-frame structure according to an embodiment of the present invention;", "FIGS. 6 , 6 A, and 6 B are schematic illustrations of super-frame structure according to an embodiment of the present invention;", "FIG. 7 is a schematic illustration of a super-frame structure having a new preamble multiplexed with a legacy preamble according to an embodiment of the present invention;", "FIG. 8 is a schematic illustration of a super-frame structure having a supplemental preamble multiplexed with a legacy preamble, where the new preamble may be obscured from legacy terminals, according to an embodiment of the present invention;", "FIG. 9 is a schematic illustration of a frame structure partitioned in the time and/or frequency domain according to an embodiment of the present invention;", "FIG. 10 is a schematic illustration of a frame structure in FDD duplex mode according to an embodiment of the present invention;", "FIGS. 11-13 are schematic illustrations of frame structures, according to embodiments of the present invention;", "FIG. 14 is a table of OFDMA parameters according to embodiments of the present invention;", "and FIG. 15 is a flow chart of a method according to an embodiment of the present invention.", "It will be appreciated that for simplicity and clarity of illustration, elements shown in the drawings have not necessarily been drawn accurately or to scale.", "For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity or several physical components included in one functional block or element.", "Further, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements.", "Moreover, some of the blocks depicted in the drawings may be combined into a single function.", "DETAILED DESCRIPTION OF THE INVENTION In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention.", "However it will be understood by those skilled in the art that the present invention may be practiced without these specific details.", "In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.", "Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices.", "In addition, the term “plurality”", "may be used throughout the specification to describe two or more components, devices, elements, parameters and the like.", "While the following detailed description may describe various embodiments of the present invention in relation to wireless networks utilizing orthogonal frequency division multiplexing (OFDM) modulation, the embodiments of present invention are not limited thereto and, for example, may be implemented using other modulation and/or coding schemes where suitably applicable.", "Further, while example embodiments are described herein in relation to wireless metropolitan area networks (WMANs), the invention is not limited thereto and can be applied to other types of wireless networks where similar advantages may be obtained.", "Such networks specifically include, but are not limited to, wireless local area networks (WLANs), wireless personal area networks (WPANs), and/or wireless wide area networks (WWANs).", "The following inventive embodiments may be used in a variety of applications including transmitters and receivers of a radio system, although the present invention is not limited in this respect.", "Radio systems specifically included within the scope of the present invention include, but are not limited to, network interface cards (NICs), network adaptors, mobile stations, base stations, access points (APs), gateways, bridges, hubs and cellular radiotelephones.", "Further, the radio systems within the scope of the invention may include cellular radiotelephone systems, satellite systems, personal communication systems (PCS), two-way radio systems, two-way pagers, personal computers (PCs) and related peripherals, personal digital assistants (PDAs), personal computing accessories and all existing and future arising systems which may be related in nature and to which the principles of the inventive embodiments could be suitably applied.", "Reference is made to FIG. 1 , which schematically illustrates a wireless network 100 according to an embodiment of the present invention.", "Wireless network 100 may include provider network (PN) 120 , a base station (BS) 118 , and one or more subscriber or other stations 110 , 112 , 114 , and/or 116 , which may be for example mobile or fixed subscriber stations.", "In some embodiments, base station 118 , for example, in WLANs, may be referred to as an access point (AP), terminal, and/or node, and subscriber stations 110 , 112 , 114 , and/or 116 may be referred to as a station (STA), terminal, and/or node.", "However, the terms base station and subscriber station are used merely as an example throughout this specification and their denotation in this respect is in no way intended to limit the inventive embodiments to any particular type of network or protocols.", "Wireless network 100 may facilitate wireless access between each of subscriber stations 110 , 112 , 114 , and/or 116 and PN 120 .", "For example, wireless network 100 may be configured to use one or more protocols specified in by the Institute of Electrical and Electronics Engineers (IEEE) 802.11™ standards (“IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification. 1999 Edition”, reaffirmed Jun. 12, 2003), such as IEEE 802.11a™-1999;", "IEEE 802.11b™-1999/Cor1-2001;", "IEEE 802.11g™-2003;", "and/or IEEE 802.11n™, in the IEEE 802.16™ standards (“IEEE Standard for Local and Metropolitan Area Networks—Part 16: Air Interface for Fixed Broadband Wireless Access System”, Oct. 1, 2004), such as IEEE 802.16-2004/Cor1-2005 or IEEE Std 802.16-2009, which may herein be referred to as the “IEEE Std 802.16-2009”", "or “WiMAX”", "standards, and/or in the IEEE 802.15.1™ standards (“IEEE Standard for Local and Metropolitan Area Networks—Specific Requirements. Part 15.1: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications for Wireless Personal Area Networks (WPANs™)”, Jun. 14, 2005), although the invention is not limited in this respect and other standards may be used.", "In some embodiments, attributes, compatibility, and/or functionality of wireless network 100 and components thereof may be defined according to, for example, the IEEE 802.16 standards (e.g., which may be referred to as a worldwide interoperability for microwave access (WiMAX)).", "Alternatively or in addition, wireless network 100 may use devices and/or protocols that may be compatible with a 3 rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) cellular network or any protocols for WPANs or WWANs.", "Embodiments of the invention may enable the next generation of mobile WiMAX systems (e.g., based on IEEE 802.16m standard) to efficiently support substantially high mobility and low latency applications, such as, for example, Voice-over-Internet Protocol (VoIP), interactive gaming over the air-interface, deployment in larger cell-sizes or lower frequency bands, and/or “multi-hop”", "relay operations, while enabling backward compatible operations and integration with reference standards (e.g., the legacy mobile WiMAX systems based on IEEE Std 802.16-2009).", "In some embodiments, base station 118 may manage and/or control wireless communications among subscriber stations 110 , 112 , 114 , and/or 116 and between subscriber stations 110 , 112 , 114 , and/or 116 and provider network 120 .", "Subscriber stations 110 , 112 , 114 , and/or 116 may, in turn, facilitate various service connections of other devices (not shown) to wireless network 100 via a private or public local area network (LAN), although the embodiments are not limited in this respect.", "Reference is made to FIG. 2 , which schematically illustrates an apparatus 130 for use in a wireless network according to an embodiment of the invention.", "For example, apparatus 130 may be a terminal, device, or node (e.g., one of subscriber stations 110 , 112 , 114 , and/or 116 , base station 118 , and/or provider network 120 , described in FIG. 1 ) for communicating with other terminals, devices, or nodes, in a wireless network (e.g., wireless network 100 , described in FIG. 1 ).", "Apparatus 130 may include a controller or processing circuit 150 including logic (e.g., including hard circuitry, processor and software, or a combination thereof) to determine the false frame detection rate and/or adjust the sensitivity of frame detection as described in one or more embodiments of the invention.", "In some embodiments, apparatus 130 may include a radio frequency (RF) interface 140 and/or a medium access controller (MAC)/baseband processor circuit 150 .", "In one embodiment, RF interface 140 may include a component or combination of components adapted for transmitting and/or receiving single carrier or multi-carrier modulated signals (e.g., including complementary code keying (CCK) and/or orthogonal frequency division multiplexing (OFDM) symbols) although the inventive embodiments are not limited to any specific over-the-air interface or modulation scheme.", "RF interface 140 may include, for example, a receiver 142 , a transmitter 144 and/or a frequency synthesizer 146 .", "Interface 140 may include bias controls, a crystal oscillator and/or one or more antennas 148 and/or 149 .", "In another embodiment, RF interface 140 may use external voltage-controlled oscillators (VCOs), surface acoustic wave filters, intermediate frequency (IF) filters and/or RF filters, as desired.", "Due to the variety of potential RF interface designs an expansive description thereof is omitted.", "Processing circuit 150 may communicate with RF interface 140 to process receive and/or transmit signals and may include, for example, an analog-to-digital converter 152 for down converting received signals, a digital-to-analog converter 154 for up converting signals for transmission.", "Further, processor circuit 150 may include a baseband or physical layer (PHY) processing circuit 156 for PHY link layer processing of respective receive/transmit signals.", "Processing circuit 150 may include, for example, a processing circuit 159 for medium access control (MAC)/data link layer processing.", "Processing circuit 150 may include a memory controller 158 for communicating with processing circuit 159 and/or a base station management entity 160 , for example, via interfaces 155 .", "In some embodiments of the present invention, PHY processing circuit 156 may include a frame construction and/or detection module, in combination with additional circuitry such as a buffer memory, to construct and/or deconstruct super-frames as in the embodiments previously described.", "Alternatively or in addition, MAC processing circuit 159 may share processing for certain of these functions or perform these processes independent of PHY processing circuit 156 .", "In some embodiments, MAC and PHY processing may be integrated into a single circuit if desired.", "Apparatus 130 may be, for example, a base station, an access point, a subscriber station, a device, a terminal, a node, a hybrid coordinator, a wireless router, a NIC and/or network adaptor for computing devices, a mobile station or other device suitable to implement the inventive methods, protocols and/or architectures described herein.", "Accordingly, functions and/or specific configurations of apparatus 130 described herein, may be included or omitted in various embodiments of apparatus 130 , as suitably desired.", "In some embodiments, apparatus 130 may be configured to be compatible with protocols and frequencies associated one or more of the IEEE 802.11, 802.15 and/or 802.16 standards for WLANs, WPANs and/or broadband wireless networks, cited herein, although the embodiments are not limited in this respect.", "Embodiments of apparatus 130 may be implemented using single input single output (SISO) architectures.", "However, as shown in FIG. 2 , certain implementations may include multiple antennas (e.g., antennas 148 and 149 ) for transmission and/or reception using adaptive antenna techniques for beamforming or spatial division multiple access (SDMA) and/or using multiple input multiple output (MIMO) communication techniques.", "The components and features of station 130 may be implemented using any combination of discrete circuitry, application specific integrated circuits (ASICs), logic gates and/or single chip architectures.", "Further, the features of apparatus 130 may be implemented using microcontrollers, programmable logic arrays and/or microprocessors or any combination of the foregoing where suitably appropriate.", "It is noted that hardware, firmware and/or software elements may be collectively or individually referred to herein as “logic”", "or “circuit.”", "It should be appreciated that the example apparatus 130 shown in the block diagram of FIG. 2 may represent one functionally descriptive example of many potential implementations.", "Accordingly, division, omission or inclusion of block functions depicted in the accompanying figures does not infer that the hardware components, circuits, software and/or elements for implementing these functions would be necessarily be divided, omitted, or included in embodiments of the present invention.", "Reference is made to FIG. 3 , which schematically illustrates a frame 300 structure according to an embodiment of the present invention.", "Frame 300 (e.g., a radio frame) may be a portion of a transmitted and/or received communication in, for example, wireless network 100 .", "In some embodiments, frame 300 may describe a periodically repeating segment structure of a larger communication signal or stream.", "In some embodiments, repeating frame 300 may include substantially different information, for example, during substantially each separate transmission.", "Frame 300 may be defined and may include broadband wireless access technology according to, for example, the IEEE Std 802.16-2009 or mobile WiMAX profiles.", "According to the mobile WiMAX profiles, the duration of frame 300 or transmission time interval (TTI) may be, for example, approximately 5 ms.", "Other frame or radio frame sizes such as for example 2, 2.5, 4, 8, 10, 12, and 20 ms may be used as for example specified in the IEEE Std 802.16-2009 specification.", "In some embodiments, frame 300 may be transmitted and/or received, for example, according to a time division duplex (TDD) mode or scheme.", "Other time and/or frequency schemes may be used (e.g., such as a frequency division duplex (FDD) mode or scheme) according to embodiments of the invention.", "Frame 300 may include an integer number of OFDM symbols or other multiplexing symbols.", "The number of OFDM symbols per frame may be determined, for example, according to a choice of OFDM numerology (e.g., sub-carrier spacing, cyclic prefix length, sampling frequency, etc.).", "In some embodiments, OFDM numerologies may be determined, set, or obtained, for example, depending, on a bandwidth and sampling frequency (e.g., or an over-sampling factor according to the mobile WiMAX profiles).", "In various embodiments, substantially different OFDM numerologies may be used, which may result in substantially different number of OFDM symbols in frame 300 .", "In some embodiments, frame 300 may include idle symbols and/or idle time slots.", "In one embodiment, frame 300 may include one or more switching periods 302 and/or 304 , for example, for changing between a pre-designated downlink (DL) transmission 306 and a pre-designated uplink (UL) transmission 308 when a TDD duplex mode or scheme is used.", "In other embodiments, for example, when an FDD duplex scheme is used, since DL transmissions 306 and UL transmissions 308 may be sent substantially at the same or overlapping times (e.g., over different frequencies or network channels) frame 300 may include substantially few or no idle symbols, idle time slots, and/or switching periods 302 and/or 304 .", "In some embodiments, the TTI or the duration of frame 300 may be, for example, approximately 5 ms.", "A round trip time (RTT) (e.g., the time interval between two consecutive pre-scheduled DL transmissions 306 to a specific wireless node may be, for example, approximately 10 ms.", "Wireless networks (e.g., wireless network 100 ) having rapidly changing channel conditions and/or small coherence times (e.g., rapidly moving mobile stations or nodes, such as automobiles having vehicular speeds of, for example, in the excess of approximately 120 kilometers per hour (km/h)) may use mechanisms for supporting substantially high mobility in varying channel conditions.", "Embodiments of the invention may support wireless network 100 having substantially small round trip times, for example, to enable substantially fast-varying channel condition feedback between subscriber stations 110 , 112 , 114 , and/or 116 , such as a mobile station, and base station 118 .", "Other time durations may be used.", "The current IEEE Std 802.16-2009 specification standard frame structure may include restrictions, such as substantially long TTIs that are typically not suitable for supporting substantially fast feedback and low access latency (e.g., less than 10 ms), which may be used by, for example, emerging radio access technologies.", "Embodiments of the present invention may include or use a modified version of the frame 300 structure for supporting lower latency operations, while maintaining backward compatibility, for example, to the IEEE Std 802.16-2009 specification frame structure.", "Frame 300 structure may be used, for example, in the next generation of mobile WiMAX systems and devices (e.g., including the IEEE 802.16m standard).", "In some embodiments, frame 300 structure or portions thereof may be transparent to the legacy terminals (e.g., which operate according to mobile WiMAX profiles and IEEE Std 802.16-2009) and may be used only for communication between BSs, subscriber stations, and/or MSs that both operate based on the IEEE 802.16m standard.", "According to embodiments of the invention, wireless network 100 and components thereof, which may communicate using the new frame structure (e.g., described according to FIGS. 3-15 ), may be backward compatible with a reference network, which may communicate using a legacy frame structure (e.g., described according to the mobile WiMAX profiles and based on the IEEE Std 802.16-2009).", "In some embodiments, backward compatibility may include for example, that a legacy terminal (e.g., which may communicate using legacy and/or reference frame structures) may operate in a wireless network with no significant impact on the performance and operation of the terminal relative to a legacy network.", "In some embodiments, a new (e.g., a non-legacy) terminal or subscriber station using the new (e.g., a non-legacy) frame structure may operate in a legacy network with no significant impact on the performance and operation of the terminal relative to the wireless network.", "For example, the new terminal may be “backward compatible.”", "In some embodiments, wireless network 100 may support both legacy and new (e.g., a non-legacy) terminals, for example, at substantially the same time (e.g., where time division multiplexing of the new and legacy frames overlap in the same frame).", "In some embodiments, wireless network 100 may enable seamless communication, mobility, and handoff between legacy terminals and new terminals.", "When used herein, “new”, “evolved”", "or “updated,” and “next generation”", "are merely relative to “old”, “legacy”", "or “current”, etc.", "For example, a “new”", "standard may be a standard that is in use as of the date of the filing of this application, and a “legacy”", "system may be one that is in use both prior to the date of filing this application and for some time after the filing of this application;", "a “new”", "system is one implemented or developed after a “legacy”", "system, typically including improvements and updates.", "“New”, “evolved”, “updated”, etc.", "systems are often backward compatible such that they are usable with “old”, “legacy”", "or prior systems or standards.", "According to embodiments of the invention, the new frame structure may include new synchronization and broadcast channels to extend the capabilities of the IEEE Std 802.16-2009 by, for example, enhancing system acquisition and/or enhancing cell selection at low signal to interference+noise ratios (SINR).", "According to the IEEE Std 802.16-2009 a broadcast channel (e.g., and a DL channel descriptor and UL channel descriptor) are typically not located at a pre-defined location in a frame, the mobile stations have to decode the common control channel (e.g., MAP) for acquiring system configuration information.", "According to an embodiment of the present invention, the new frame structure may include for example a super-frame that includes an integer number of radio frames, which may include synchronization and/or broadcast information and/or messages, such as, system configuration information, which may simplify wireless network 100 operations and further reduce the overhead and acquisition latency of wireless network 100 .", "Reference is made to FIG. 4 , which schematically illustrates a super-frame 400 structure according to an embodiment of the present invention.", "In some embodiments, a transmission between terminals or nodes may include, for example, one or more super-frames 400 .", "Super-frame 400 may include or be partitioned into a fixed and/or pre-determined number of frames 410 .", "In other embodiments, the number of frames 410 in each of two or more of super-frames 400 may be different.", "The number of frames, M, 410 within a super-frame 400 (e.g., M, may be an integer, where M=2, 3, 4 .", ".) may be a design parameter and may be specified in a standard specification and, for example, may be fixed for a particular profile and deployment.", "In some embodiments, the number of frames 410 within super-frame 400 may be determined by one or more factors, including but not limited to, for example, target system acquisition time, a maximum permissible distance between two consecutive preambles (e.g., synchronization channels), the minimum number of preambles that may be averaged during system acquisition for the detection of the preamble, and/or a maximum permissible distance between two consecutive broadcast channels (e.g., system configuration information or paging channels).", "In one embodiment, substantially each super-frame 400 may be partitioned into or include two or more (e.g., four (4)) frames 410 .", "Other numbers of partitions, divisions, or frames may be used.", "The length of each frame 410 may be for example approximately 5 ms, for example, for establishing backward compatibility with systems compliant with IEEE Std 802.16-2009.", "Other frame or radio frame lengths may be used.", "Each of frames 410 may be further partitioned or sub-divided into two or more (e.g., eight (8)) sub-frames 420 .", "Other numbers of divisions may be used.", "The length of sub-frame 420 may determine the TTI for terminals that may be compliant with the new standard and, for example, incorporate super-frame 400 and/or frame 410 structures.", "The beginning and end of each of the TTIs may be substantially aligned or synchronized with, for example, a sub-frame boundary.", "Each TTI may contain an integer number of sub-frames (e.g. typically one or two sub-frames).", "Each sub-frame 420 may be partitioned into or include a fixed number of OFDM symbols 430 .", "In one embodiment, each sub-frame 420 may be partitioned into or include, for example, six (6) OFDM symbols, so that the number of OFDM symbols 430 within a sub-frame (e.g., the length of sub-frame 420 ) may be compatible to resource block sizes (e.g., sub-channels) corresponding to various permutation schemes, for example, specified in the IEEE Std 802.16-2009.", "In other embodiments, there may be other or alternative numbers, lengths, sizes, and/or variations, of super-frames 400 , frames 410 , sub-frames 420 , and/or OFDM symbols 430 .", "The numbers used herein are presented for demonstrative purposes only.", "In another embodiment, the length of frames 410 (e.g., approximately 5 ms) and the number of OFDM symbols 430 (e.g., six (6)), may be set for establishing backward compatibility with IEEE Std 802.16-2009 compliant systems, devices, and/or transmissions.", "Permutation schemes, for example, defined according to current standard specifications, may include a number, for example, from one to six, slots for transmitting signals and/or resource blocks.", "The boundary of physical a resource block may, for example, be aligned with a sub-frame boundary.", "In some embodiments, each physical resource block may be substantially contained within a single sub-frame 420 .", "In other embodiments, each physical resource block may be substantially contained within two consecutive sub-frames.", "It may be appreciated by those skilled in the art that embodiments of the invention, for example, including, super-frame 400 structures, may be applied using either of the TDD and FDD duplexing schemes or modes.", "In the FDD duplex mode, each of the DL and UL transmissions may be communicated, for example, concurrently, on respective frequencies or channels.", "In the TDD duplex mode, each of the DL and UL transmissions may be communicated, for example, at substantially non-overlapping intervals (e.g., according to time division multiplexing (TDM) scheme) over substantially the same frequency or channel.", "In the TDD duplex mode of operation and within any frame 410 , sub-frames 420 may be configured to DL and UL transmissions (e.g., DL transmission 306 and UL transmission 308 ) for example statically in each deployment.", "The DL and UL transmissions may be separated by idle times and/or idle symbols for switching between DL and UL transmissions (e.g., during switching periods 302 and/or 304 ).", "In one embodiment of the invention, “legacy zones”", "and “new zones”", "may include periods, portions or zones, for example, of DL or UL transmission, specifically designed to substantially only communicate with legacy terminals or new terminals, respectively.", "In the TDD duplex mode of the IEEE Std 802.16-2009, each of DL transmission 306 and UL transmission 308 may be further partitioned into two or more permutation zones.", "In some embodiments, the number of contiguous OFDM or other symbols 430 in a frame 410 , may be referred to as, for example, a permutation zone (e.g., permutation zone 310 , described in reference to FIG. 3 ).", "The permutation zone may, for example, include a number of contiguous OFDM symbols (e.g., in DL and UL transmissions 306 and 308 , described in reference to FIG. 3 ) that use substantially the same permutation (e.g., partially used sub-channel (PUSC) to distributed allocation of sub-carriers, Adaptive Modulation and Coding (AMC) for localized allocation of sub-carriers, etc.).", "According to an embodiment of the invention, a frame may include or may be partitioned into legacy zones and new zones (other terms may be used).", "In one embodiment, legacy terminals and new terminals may communicate using legacy zones and new zones, respectively.", "In some embodiments, new terminals may communicate using both legacy zones and new zones.", "Legacy terminals typically only communicate using legacy zones.", "In one embodiment, in the frame, each of DL transmissions may be further partitioned into two or more zones, for example, including a DL transmission legacy zones and a DL transmission new (e.g., non-legacy) zones and each of UL transmissions may be further partitioned into two or more zones, for example, including UL transmission legacy zones and UL transmission new (e.g., non-legacy) zones.", "Embodiments of the invention may provide a partitioning of frames into sub-frames (e.g., where the boundaries of transmission blocks or zones may be synchronized with the sub-frame boundaries).", "According to the IEEE Std 802.16-2009, the boundaries of transmission blocks or zones may start and end at any OFDM symbol within the boundary of a frame.", "According to embodiments of the invention, the new zones may use a new and more efficient resource allocation and feedback mechanism.", "The total number of OFDM symbols within a frame may vary depending on the OFDM numerology.", "In order to maintain backward compatibility with the legacy mobile WiMAX systems, the same frame size and OFDMA numerology (e.g., or OFDMA parameters) may be used for the IEEE 802.16m systems and the legacy mobile WiMAX systems.", "It may be appreciated by those skilled in the art that all permissible numerologies and/or frame sizes, for example, specified by the 802.16e-2005 standard, may be used in accordance with embodiments of the present invention.", "Embodiments of the invention may provide super-frame structures that may be compatible with legacy standards, such as, the IEEE Std 802.16-2009 and/or other standards.", "For example, the super-frame structure may include or may be compatible with a subset of features, for example, as specified in the mobile WiMAX profile (e.g., and may be backwards compatible with the mobile WiMAX profile).", "Embodiments of the invention may provide a super-frame structure, which may be partitioned into a number of frames that include, for example, one or more, legacy synchronization channel (e.g., a IEEE Std 802.16-2009 preamble), new synchronization channels (e.g., a IEEE 802.16m preamble), broadcast channel (BCH), medium access protocol (MAPs) or common control channel (CCCH) in the new and legacy zones corresponding to each frame or an integer number of frames.", "Reference is made to FIG. 5 , which schematically illustrates a super-frame 500 structure according to an embodiment of the present invention.", "In one embodiment, super-frame 500 may include a legacy preamble 502 , for example, which may be referred to as primary synchronization channel (PSCH).", "In some embodiments, super-frame 500 may include an additional or supplemental preamble 504 , for example, for improving system timing acquisition and cell selection for new terminals.", "Supplemental preamble 504 may, for example, be referred to as secondary synchronization channel (SSCH).", "The synchronization channels may include sequences, which may be used and/or deciphered by both base stations and mobile stations, for example, for acquiring frame timing and/or scheduling.", "In some embodiments, new preamble 504 may be effectively or partially transparent, unreadable, or undetectable to legacy terminals, while legacy preamble 502 may be detectable to both legacy and new terminals.", "In some embodiments, super-frame 500 may include a broadcast channel (BCH) 506 .", "The broadcast channel may contain information that may for example include system configuration information, paging, and/or other broadcast type information, and may be sent by a base station to all mobile stations in the network and/or surrounding area.", "As shown in FIG. 5 , supplementary or new preamble 504 (e.g., SSCH) may be located at a fixed position in new or legacy zones.", "In one embodiment of the present invention, for example, the new preamble 504 may be positioned at a fixed offset, which may be referred to as, for example, “SSCH_OFFSET.”", "The SSCH_OFFSET may be a measure of a location of the new preamble 504 , for example, relative to the location of the legacy preamble, for example, in every frame.", "In some embodiments, the legacy preamble in mobile WiMAX systems may be located in the first OFDM symbol of every frame (as shown in FIG. 9 ).", "The value of SSCH_OFFSET may be included and broadcasted as part of the system configuration information.", "In some embodiments, when new preamble 504 is detected by a mobile terminal, the SSCH_OFFSET may be used to locate the beginning of a frame.", "In one embodiment, when SSCH_OFFSET=0, there may be no legacy preamble 502 , which may indicate that the network does not support legacy terminals.", "In some embodiments, a new synchronization channel and the broadcast channel may span a minimum system bandwidth (BW).", "In some embodiments, the legacy synchronization channel typically spans the entire system BW, an example of which is shown in FIG. 9 .", "The region pre-designated for communicating new preamble 504 (e.g., via multiple sub-carriers) may be, for example, transparent and/or ignored by legacy terminals.", "A scheduler for downlink base station or terminal transmissions typically does not allocate user/system traffic/control/signaling in the region pre-designated for communicating new preamble 504 .", "In another embodiment of the present invention, for example, new preamble 504 may be located, for example, in the beginning of the new frame where the new frame may be located at a fixed offset relative to the legacy frame.", "In one embodiment, the fixed offset may be referred to as, for example, “FRAME_OFFSET”, and may be fixed within the frame timing.", "In some embodiments, the value of the FRAME_OFFSET may be set by a network operator or administrator (e.g., and not broadcast).", "The new mobile terminals may detect new preamble 504 , which may indicate the beginning of the new frame and, for example, other information channels relative to the beginning of the new frame (e.g., as shown in FIG. 6 ).", "For example, the timing or periodicity of BCH 506 may be substantially aligned with the timing or periodicity of super-frame 500 transmissions.", "In various embodiments, super-frame 500 may have substantially different structures, which may be distinguished, for example, based on the relative position of legacy preamble 502 and/or new preamble 504 in super-frame 500 , and/or other features or design considerations for the frame structure (e.g., such as a DL scan latency, physical layer overhead, and other information).", "It may be appreciated to those skilled in the art that although three options for the structure of super-frame 500 , including for example, options I, II, and III, may be described, various other structures and/or variations thereof may be used in accordance with embodiments of the present invention.", "The description that follows may include embodiments that may individually or collectively be referred to as Option I. Option I, and other “Options”", "presented herein are examples only, and are non-limiting.", "In some embodiments, new preamble 504 and/or BCH 506 may be positioned substantially at the beginning of each super-frame 500 , for example, in the first frame of each super-frame 500 in a communication stream.", "In such embodiments, legacy preamble 502 and new preamble 504 may be separately positioned (e.g., spaced or offset along the length of super-frame 500 ).", "In such embodiments, the impact or visibility of new preamble 504 to legacy terminals (e.g., which typically only detect legacy preamble 502 ) and operations thereof, such as, system acquisition, may be minimized.", "New preamble 504 may be periodically repeated at any desirable frequency, for example, substantially every frame.", "BCH 506 may contain system-configuration information, paging channels, and/or other broadcast information.", "In some embodiments, BCH 506 may be synchronized with super-frame 500 intervals and may appear every integer number of super-frames.", "In some embodiments, new terminals may use new preamble 504 (e.g., exclusively or additionally) to improve system timing acquisition and fast cell selection.", "For example, new preamble 504 may include cell identification (ID) information or codes and may be used for acquisition of frame timing by new terminals.", "For example, a cell ID code may include a concatenated base station group ID code, base station ID code, a sector ID code, and/or other codes or information, for example, to simplify the detection (e.g., execute a structured search) of the cell ID.", "According to embodiments of the invention described in reference to Option I, since new preamble 504 may be spaced from legacy preamble 502 , new preamble 504 may be minimally detectable by legacy terminals.", "In some embodiments, in order to minimize the physical layer overhead (layer 1 overhead), for example, which may be increased by using an OFDM symbol for transmitting new preamble 504 , new preamble 504 may be transmitted, for example, over a limited (e.g., minimal) bandwidth or time, or by using additional sub-carriers corresponding to the same OFDM symbol for scheduling user traffic, for example, as shown in FIG. 9 .", "The description that follows may include embodiments that may individually or collectively be referred to as Option II.", "Reference is made to FIG. 6 , which schematically illustrates a super-frame 600 structure according to an embodiment of the invention.", "In some embodiments for TDD duplex mode, super-frame 600 may be partitioned into, for example, four frames with pre-designated legacy periods, intervals or zones and new or non-legacy periods, intervals or zones.", "In one embodiment, legacy frame 610 may be further partitioned into sub-frames, including, for example, DL transmission legacy zones 612 and UL transmission legacy zones 616 .", "The new frame 620 may begin at a fixed offset (e.g., FRAME_OFFSET) relative to the beginning of the legacy frame.", "The value of the FRAME_OFFSET may be an integer number of sub-frames and may be determined based on the ratio of the lengths or time of the DL to UL transmissions (e.g., in TDD duplex mode).", "For example, when FRAME_OFFSET=T offset and T sub-frame denotes the length of the sub-frame and T f denotes the frame length the value of the minimum and maximum permissible values for T offset may be determined as follows: T offset <αT f 0≦α≦1: the fraction of frame allocated to DL Example: α=0.625 for DL:UL=5:3 nT sub-frame ≦αT f −T offset 1 ≦n<", "7 T offset =mT sub-frame 0≦ m<", "(Number of DL Sub_Frames)− n In some embodiments, legacy terminals may communicate using legacy frames 610 and new terminals may communicate using new frames 620 and/or legacy frames 610 .", "According to embodiments of the invention, for example, in option III, the beginning of new frames 620 and legacy frames 610 may be offset by a fixed value, for example, by a frame offset 622 or an offset interval (e.g., a fixed duration of time and/or number of sub-frames).", "The relative positions of new frames 620 and legacy frames 610 according to one embodiment are depicted in FIG. 6 , for example, in TDD duplex mode.", "For example, in TDD duplex mode, legacy frame 610 structure may start with a DL transmission 612 and end with an UL transmission 616 .", "For example, new frame 610 structure may start with a DL transmission 614 , followed by a UL transmission 618 , and end with a DL transmission 614 .", "In some embodiments, each new frame 610 may contain a new preamble (e.g., SSCH), for example, in a sub-frame at the start or beginning of frame 610 .", "In other embodiments, each super-frame 600 may include a super-frame header (SFH) 624 , for example, in a sub-frame at the start or beginning of super-frame 600 .", "For example, SFH 624 may include a new preamble and a broadcast channel.", "For example, K and 6-K, K=1, 2, .", ", 6 may denote the number of OFDM symbols that are allocated to new preamble and broadcast channel, respectively.", "The number of OFDM symbols allocated to the new and legacy preambles may be as small as one OFDM symbol per channel.", "In one embodiment, the remainder of the OFDM symbols available in the SFH 624 sub-frame may be allocated, for example, for user traffic, control, and/or control and signaling information, which may minimize the system layerl overhead.", "SFH 624 may include a new preamble sequence and the broadcast information (e.g., including system configuration information and a paging channel).", "In some embodiments, legacy frames and new frames may have a fixed frame offset 622 , which may be configurable by the network operator.", "In some embodiments of the present invention, the legacy zone and new zone may be offset by a fixed number of sub-frames.", "The offset value may be substantially stable or fixed within a practical deployment.", "Due to the dynamic nature of network traffic in practice, in some frames, the legacy zone may be under-utilized while the new zone may be fully loaded or vice versa.", "In some embodiments, a pointer in a IEEE 802.16m common control channel may be designed and/or used, for example, to point to or indicate a sub-frame in the legacy zone that may be unused by legacy terminals.", "For example, when legacy zone and/or new zone partitions are fixed, the resources (e.g., sub-frames) may be dynamically allocated from frame to frame maximize the use of physical resources, which may otherwise be unused.", "The description that follows may include embodiments that may individually or collectively be referred to as Option III.", "Reference is made to FIG. 7 , which schematically illustrates a super-frame 700 structure having a new preamble 704 multiplexed with a legacy preamble 702 , according to an embodiment of the present invention.", "In some embodiments, a new preamble 704 may be multiplexed with a legacy preamble 702 , for example, every M frames (e.g., where M may be the number of frames within a super-frame 700 ).", "For example, the first OFDM symbol of the first frame 710 in super-frame 700 may include new preamble 704 and the M- 1 succeeding frames 710 in super-frame 700 may include legacy preamble 702 .", "In some embodiments, a common control channel (e.g., including DL and UL MAPS) and/or frame control header (FCH) 708 and a BCH 706 transmission may occur, for example, at super-frame 700 and frame 710 intervals, respectively.", "The acquisition of legacy preamble 702 (e.g., by legacy terminals) may break as a result of interruption in the reception of the periodic legacy preamble 702 .", "Since new preamble 704 and legacy preamble 702 may share physical resources, for example, and may be transmitted at substantially the same or overlapping times or locations along super-frame 700 , there may typically be no additional physical resource needed for including the new preamble 704 into a super-frame 700 structure.", "Additionally, in some embodiments, the position of new preamble 704 may be fixed within a periodic number (one or more) of frames 710 .", "In some embodiments, when new preamble 704 and legacy preamble 702 are code division multiplexed, for example, in substantially the same OFDM symbol, there is typically no substantial impact on the layerl overhead.", "In such embodiments, some legacy preambles 702 may be transmitted in succession and, for example, other legacy preambles 702 may be superimposed with new preamble 704 (e.g., according to multiplexing scheme discussed herein).", "In some embodiments, new preamble 704 may be multiplexed with legacy preamble 702 using, for example, a code division multiplexing (CDM) scheme.", "A CDM scheme may include code division multiplexing new preamble 704 and legacy preamble 702 , for example, substantially every M frames 710 , for example, as shown in FIG. 7 .", "In one embodiment, new preamble 704 and legacy preamble 702 sequences may be superimposed and transmitted (e.g., by a new base station or terminal) every M frames, for example, according to the following equation: y k =u k +x k u′ k where u k , u′ k , x k may denote the k th primary synchronization sequence, the k th new synchronization sequence, and the k th spreading function.", "Other (e.g., linear) combinations may be used.", "For example, the spreading function may include a set of robust spreading functions, which may substantially cover the new synchronization sequences.", "Other multiplexing schemes or combinations thereof may be used.", "In one embodiment, legacy preamble 702 and new preamble 704 may be, for example, code division multiplexed every fixed number (e.g., M=1, 2, 3 .", ") frames.", "In such embodiments, legacy terminals may experience or include a small degradation in the energy of the legacy preamble every M frames.", "The new terminals may detect and extract new preamble 704 that may encroach or may be superimposed on legacy preamble 702 .", "As presented herein, new preamble may be referred to, for example, as “new preamble”, “new preamble”, “new synchronization channel”, “SSCH”", "and “secondary synchronization channel”, a new system, profile, and/or standard, may be referred to, for example, as an “evolved version”", "of the reference system standard.", "Reference is made to FIG. 8 , which schematically illustrates a super-frame 800 structure having a new preamble 804 multiplexed with a legacy preamble 802 , where legacy preamble 802 may be obscured from legacy terminals, according to an embodiment of the present invention.", "In some embodiments, the superposition of new preamble 804 on the legacy preamble 802 may, for example, increase interference levels or, for example, an interference over thermal 820 (IoT) value.", "The objective is to find the minimum Signal to Interference+Noise Ratio (SINR) that is required for proper detection of the legacy preamble or alternatively the maximum IoT that can be tolerated by the legacy terminals (this leads to the maximum power that can be used for the new preamble).", "In one embodiment of the present invention, a signal received at the s th sub-carrier, y s , may be calculated, for example, as shown in the equations that follow.", "In one embodiment, new preamble 804 associated with each new base station or relay station may be substantially different, for example, for enabling a mobile station to distinguish, detect, and/or select, different base stations or relay stations in a network.", "In some embodiments, since the received power 822 of new preamble 804 may be determined, or be directly proportional to, the IoT 820 , it may be desirable for the IoT 820 to be maximized, for example, to the extent that the minimum SINR level would allow the legacy terminals to correctly detect legacy preambles 802 .", "In some embodiments, an optimization of the IoT 820 value may be performed, for example, according to the equations that follow: y s = H s , k ⁢ u k + H s , k ⁢ χ k ⁢ u k ′ + w s + ∑ i ≠ k ⁢ H s , i ⁢ u i + ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′ SINR s = 20 ⁢ log 10 ⁢  H s , k ⁢ u k   H s , k ⁢ χ k ⁢ u k ′ + w s + ∑ i ≠ k ⁢ H s , i ⁢ u i + ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  SINR s ≥ 10 ⁢ ⁢ log 10 ⁢  H s , k ⁢ u k  2  H s , k ⁢ χ k ⁢ u k ′  2 +  w s  2 +  ∑ i ≠ k ⁢ H s , i ⁢ u i  2 +  ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  2 IoT =  H s , k ⁢ χ k ⁢ u k ′  2 SINR s min = 10 ⁢ ⁢ log 10 ⁢  H s , k ⁢ u k  2  w s  2 +  ∑ i ≠ k ⁢ H s , i ⁢ u i  2 +  ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′  2 + IoT max where terms may be defined, for example, as follows: y s : Received Signal at sth Sub-Carrier u k : Legacy Preamble Sequence sent by kth BS H s,k : Multi-Path Channel Impulse Response u′ k : New Preamble Sequence sent by kth BS x k : kth Spreading Function w s : Received Noise at sth Sub-Carrier SINR s : Signal to Interference+Noise Ratios for Legacy Terminals ∑ l ≠ k ⁢ H s , l ⁢ χ l ⁢ u l ′ ⁢ : Inter-Cell Interference due to New and Legacy Preambles Other criteria for the optimization of the IoT value may be used.", "In some embodiments, when legacy preambles 702 and 802 are code division multiplexed, transmitting new preamble 704 and 804 , respectively, may have substantially no or minimal effect on the physical layer overhead of the system in which they are transmitted.", "In such embodiments, superimposing new preamble 804 onto legacy preamble 802 respectively, may limit the received power 822 of new preamble 704 and may potentially interfere with or obscure system acquisitions of legacy preamble 802 by legacy terminals, for example, due to additional interference from new preambles transmitted by neighboring base stations or relay stations.", "The effect of additional interference may be minimized, for example, using robust preamble detection algorithms, for example, having minimal sensitivity to instantaneous degradation in the preamble power.", "It may be appreciated by those skilled in the art that each of three options for embodiments of the structure of a super-frame and/or partitions thereof, including for example, embodiments described in reference to each of options I, II, and III, may be applied to both TDD and FDD duplex schemes.", "The size and distribution of the new and legacy zones and their corresponding DL and UL transmissions and/or sub-frames, may depend, for example, on factors including but not limited to the distribution of the new and legacy terminals, network load and performance optimizations for new and legacy terminals.", "Reference is made to FIG. 10 , which schematically illustrates a frame 1000 structure in FDD duplex mode according to an embodiment of the present invention.", "Frame 1000 may include sub-frames 1030 .", "In some embodiments, super-frame 1000 may include a legacy preamble 1002 , a new preamble 1004 , and a BCH 1006 , which may be transmitted every integer number of super-frame transmissions.", "In one embodiment, legacy preamble 1002 , new preamble 1004 , and/or BCH 1006 may be positioned at the beginning of frame 1000 .", "According to embodiments of the invention, in the FDD duplex mode, DL transmissions 1016 and UL transmissions 1018 may occur substantially simultaneously, for example, at different frequencies (e.g., DL frequency F 1 1024 and UL frequency F 2 1026 , respectively).", "Reference is made to FIGS. 11-13 , which schematically illustrate frame structures 1100 , 1120 , 1200 , 1220 , 1300 , and 1320 and their respective sub-frames, 1110 , 1130 , 1210 , 1230 , 1310 , and 1330 , according to various embodiments of the present invention.", "In FIG. 11 , TDD frame 1100 is shown with a DL/UL ratio of 4:3 and FDD frame 1120 for 5, 10 or 20 MHz channel bandwidth with a cyclic prefix of ¼ of useful OFDM symbol length.", "The TDD frame 1100 may consist of seven sub-frames 1110 of six OFDM symbols each and FDD frame 1120 may have the same configuration as the TDD frame to maximize commonality or may consists of six sub-frames 1110 of six OFDM symbols and one sub-frame 1130 of seven OFDM symbols.", "As an example, for an OFDM symbol duration of 114.386 microseconds (Tb) and a CP length of ¼ Tb, the length of six-symbol sub-frames 110 and seven-symbol sub-frames 1130 are 0.6857 ms and 0.80 ms, respectively.", "In this case, the transmit-to-receive transmission gap (TTG) and receive-to-transmit transmission gap (RTG) are 139.988 microseconds and 60 microseconds, respectively.", "In FIG. 12 , TDD frame 1200 is shown with a DL/UL ratio of 3:2 and FDD frame 1220 for 7 MHz channel bandwidth with a CP of ¼ Tb.", "The TDD frame 1200 may consist of five six-symbol sub-frames 1210 and the FDD frame 1220 may have the same structure as the TDD frame to maximize commonality or may consist of four six-symbol sub-frames 1210 and one seven-symbol sub-frame 1230 .", "Assuming OFDM symbol duration of 160 microseconds and a CP length of ¼ Tb, the length of six-symbol sub-frame 1210 and seven-symbol sub-frame 1230 are 0.960 ms and 1.120 ms, respectively.", "The TTG and RTG are 140 microseconds and 60 microseconds, respectively.", "In FIG. 13 , TDD frame 1300 is shown with a DL/UL ratio of 4:2 and FDD frame 1320 for 8.75 MHz channel bandwidth with a CP of ¼ Tb.", "The TDD frame 1300 has four six-symbol sub-frames 1310 and two seven-symbol sub-frames 1330 and FDD frame 1320 has three six-symbol sub-frames 1310 and three seven-symbol sub-frame 1330 .", "Assuming OFDM symbol duration of 128 microseconds and a CP length of ¼ Tb the length of six-symbol sub-frame 1310 and seven-symbol sub-frame 1330 are 0.768 ms and 0.896 ms, respectively.", "The number of OFDM symbols in a sub-frame may be related to, for example, the length of each OFDM symbol and/or the cyclic prefix value.", "However, to simplify the implementation of the system, it is desirable that all sub-frames within a frame have the same size and consists of the same number of OFDM symbols.", "Embodiments of the invention may be used having any suitable OFDMA numerology.", "It may be appreciated by those skilled in the art that although a variety of parameters (e.g., duplex modes, cyclic prefix values, OFDMA numerologies, etc.) may be used according to embodiments described herein, suitable variations may be used, for example, as depicted in the variations of FIGS. 11-13 .", "Reference is made to FIG. 14 , which is a table of OFDMA parameters according to embodiments of the present invention.", "FIG. 14 lists parameters for a CP of ¼.", "The CP length of one quarter is equal to 22.85 microseconds (for bandwidths of 5, 10 or 20 MHz) which corresponds to a cell size of approximately 5 km.", "Therefore, a delay spread of up to 22.85 microseconds can be mitigated.", "Reference is made to FIG. 15 , which is a flow chart of a method according to an embodiment of the present invention.", "In operation 1500 , a processor in a terminal may partition each frame into two or more sub-frames.", "The frames (e.g., frames 410 described in reference to FIG. 4 , or other frames) may be backward compatible with a reference system profile and for example, defined according to a reference standard system (e.g., IEEE Std 802.16-2009 or mobile WiMAX profiles).", "Thus, as compared with the frames from which sub-frames are partitioned, the sub-frames (e.g., sub-frames 420 described in reference to FIG. 4 ) may be shorter and therefore processed and transmitted/received faster with smaller periodicity.", "Transmitting according to the sub-frame structure may provide over the air communications having a periodicity on the scale of several sub-frames instead of the relatively longer periodicity of several frames.", "In operation 1505 , a transmitter may transmit one or more sub-frames during a pre-designated downlink transmission (e.g., pre-designated DL transmissions 306 , described in reference to FIG. 3 ).", "In operation 1510 , the transmitter may transmit one or more sub-frames during a pre-designated uplink transmission (e.g., pre-designated UL transmissions 308 , described in reference to FIG. 3 ) In operation 1515 , the transmitter may transmit one of the plurality of sub-frames including a legacy preamble for communicating with a legacy terminal, for example, operating according to the reference system profile during a pre-designated legacy transmission period or zone (e.g., legacy zone 612 and/or 616 , described in reference to FIG. 6 ).", "In operation 1520 , the transmitter may transmit one of the plurality of sub-frames including a new preamble for communicating with a new (e.g., a non-legacy) terminal, for example, operating according to an evolved or newer version of the reference system standard, such as, the IEEE 802.16m standard, during a pre-designated new (e.g., a non-legacy) transmission period or zone (e.g., new zone 614 and/or 618 , described in reference to FIG. 6 ).", "In various embodiments, the first and second signals may be transmitted in a TDD duplex mode or an FDD duplex mode.", "In some embodiments, when the signals are transmitted in a TDD duplex mode, operations 1505 and 1510 may be executed over substantially different time intervals, or frame positions, such that the first and second signals may be transmitted separately.", "In other embodiments, when the when the signals are transmitted in an FDD duplex mode, operations 1505 and 1510 may be executed in substantially overlapping time periods, such that the first and second signals may be transmitted over substantially distinct frequencies and/or channels.", "In some embodiments, the sub-frames may be further partitioned into two or more (e.g., six) information-carrying, multiplexing, and/or OFDM symbols.", "In some embodiments, the first and second signals may include a legacy preamble for communicating with legacy terminals operating according to the reference system profile and a new preamble for communicating with a new (e.g., a non-legacy) terminal operating according to a second system standard and/or an evolved version of the reference system.", "In one embodiment, each of the first and second sub-frames may be pre-designated for communicating with one of a legacy terminal, a non-legacy terminal, or both a legacy and non-legacy terminal.", "For example, one of two or more sub-frames in operation 1510 may be pre-designated for communicating with both a legacy and a non-legacy terminal.", "In some embodiments, the beginning of the frames, which may be pre-designated for communicating with legacy terminals and non-legacy terminals, may be offset, for example, by a fixed number of sub-frames.", "In some embodiments, a super-frame may be defined.", "For example, the super-frame may include two or more frames (e.g., the frames described in operation 1500 ) that may be transmitted in succession.", "In one embodiment, the new preamble may be transmitted substantially once during the transmission of each super-frame.", "In one embodiment, the new preamble may be transmitted substantially once every frame.", "According to embodiments such as that of Option I described herein, the legacy preamble and the new preamble may be transmitted separately, for example, at a substantially fixed distance apart along the length of the frame.", "In one embodiment, a process may execute operations 1500 , 1505 , and 1510 and need not execute operations 1515 and 1520 .", "In another embodiment, a process may execute operations 1500 , 1515 , and 1520 and need not execute operations 1505 and 1510 .", "In yet another embodiment, a process may execute operations 1500 , 1505 , 1510 , 1515 , and 1520 .", "The process may execute other sequences, orders, and/or permutations of operations described herein.", "While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.", "Embodiments of the present invention may include other apparatuses for performing the operations herein.", "Such apparatuses may integrate the elements discussed, or may comprise alternative components to carry out the same purpose.", "It will be appreciated by skilled in the art that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention." ]
BACKGROUND OF THE INVENTION This invention relates to fluid-gauging systems and fluid-gauging methods. The invention is especially, but not exclusively, concerned with fuel-gauging systems for aircraft. Measurement of the quantity of fuel within an aircraft's fuel-tanks is commonly performed by means of one or more capacitive probes arranged for immersion in any fuel present. The capacitance of the probe varies in accordance with the depth of fuel in the tank, thereby enabling an indication of fuel level to be obtained. Changes in permittivity of fuel which would affect the capacitance of the probe can be compensated for by use of a permittivity cell (which may be in the form of a parallel-plate capacitor of open construction) mounted at the bottom of the fuel-tank, so as always to be immersed in any fuel present. An indication of volume may be obtained directly if the tank is of a regular shape, that is, if the volume of fuel present varies in a linear fashion with the depth of fuel. For irregularly shaped tanks the probe may be characterised, that is, the probe plates may be suitably-shaped such that the surface area of the plates covered by fuel varies in a non-linear fashion with depth but in a manner that is directly related to the volume of fuel present. Alternatively, the output of the probe may be supplied to a computer in which is stored a model of the fuel-tank from which can be obtained an indication of the volume with knowledge of the fuel depth. In many applications, such as, for example, in aircraft, it is necessary to have an indication of the fuel mass rather than its volume. Although the mass of fuel can be readily determined by measuring its density with some form of densitometer, the cost of densitometers capable of providing the high accuracy needed in some applications can be very high. Most modern aircraft are equipped with several fuel-tanks and, because of the variations in density between different fuels, such as might be supplied to different tanks during refuelling stops at different airports, it is necessary to obtain a measure of the density of each of the different fuels and fuel mixtures within the different tanks. The cost of providing a fuel-gauging system having a densitometer mounted in each of an aircraft's fuel-tanks will therefore be correspondingly high, and, in many cases prohibitive. To avoid the need to use densitometers, it has been proposed instead to measure the permittivity of fuel with a relatively simple and inexpensive capacitive permittivity cell and to derive the density from the permittivity using a relationship of the form: D K =(K-1)/0.763(0.7+0.2(K-1)) . . . (I) where D K is the density of the fuel; and K is the permittivity of the fuel. Since the permittivity cells can be relatively inexpensive, it is possible to mount a cell in every tank and thereby compensate for fuels of different densities. The above relationship, however, is only approximate; random variations from fuel to fuel mean that errors of up to about 2% can be experienced. In the future, with fuels derived from an increasing number of sources, it is likely that even greater errors may be experienced. Although a fuel-gauging system of such limited accuracy may be satisfactory in some cases, the need to carry more fuel than is absolutely necessary, in order to allow sufficient safety margin for inaccuracies in the system, will mean that the payload that can be carried by the aircraft must be correspondingly reduced. BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluid-gauging system and method that may be used to alleviate the above-mentioned difficulties. According to one aspect of the present invention there is provided a fluid-gauging system for use in providing a representation of the mass of fluid present in a plurality of reservoirs, the system including means for providing a representation of the volume of fluid present in each said reservoir, first means associated with each said reservoir for providing a first representation of the density of fluid in each said reservoir, second means for providing a second representation of the density of fluid, said second representation being more accurate than said first representation, and means for modifying each said first representation in accordance with said second representation so as thereby to obtain a more accurate representation of the density of fluid in each said reservoir. The second means providing the second density representation may receive a sample at least of all the fluid supplied to the reservoirs. The first means may include means located in each reservoir for providing a first representation of the permittivity of fluid in each reservoir, and means for deriving, from said first permittivity representations, said first density representations. The system may further include third means for providing in respect of fluid supplied to said reservoirs, a second permittivity representation, and means for deriving, from said second permittivity representation, a third density representation. The system may include means for comparing said second density representation with said third density representation so as to derive a correction factor therefrom for use in modifying each said first density representation. The system may be arranged to derive a first correction factor in respect of a first fluid supplied to said reservoirs, said first correction factor being stored in store means, the system being arranged to derive a second correction factor in respect of a second fluid supplied to said reservoirs, and a third correction factor in respect of each said reservoir in accordance with the volumes of said first and second fluids in each said reservoir and their respective correction factors, each said first density representation being modified by use of said third correction factor. According to another aspect of the present invention there is provided a method of providing an indication of the mass of fluid present in a plurality of reservoirs, said method including the steps of deriving a representation of the volume of fluid in each said reservoir, deriving a first representation of the density of fluid in each said reservoir, deriving a second representation of the density of fluid, said second density representation being more accurate than said first density representation, and modifying each said first density representation in accordance with said second density representation so as thereby to obtain a more accurate representation of the density of fluid in each said reservoir. A fuel-gauging system and method for an aircraft, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of the system; FIG. 2 is a schematic representation of a part of the system of FIG. 1; and FIG. 3 is a flow chart indicating operation of the method and system. DETAILED DESCRIPTION With reference to FIG. 1, an inlet pipe 1 is connected to supply fuel to fuel-tanks 2, 3 and 4 (only three of which are shown in FIG. 1) mounted within the aircraft. Fuel is supplied to the aircraft engine (not shown) via outlet pipes 5, 6 and 7 extending from the bottom of each of the fuel-tanks 2, 3 and 4 respectively. Capacitive level probes 8 to 10 are mounted vertically within the tanks 2 to 4 and provide output signals C 2 , C 3 and C 4 respectively representative of the values of capacitance of the probes, which signals vary in accordance with fuel depths within the tanks. The signals C 2 , C 3 and C 4 are supplied via lines 11 to 13 to a computing unit 20 which derives a measure of the volume of fuel in each tank. A permittivity cell 21 to 23 is also mounted within each of the tanks 2 to 4 respectively. The cells 21 to 23 may each take the form of a simple parallel-plate capacitor of open construction that is mounted at the bottom of the fuel-tank so that it is always totally immersed in any fuel that may be present. The capacitances of the cells 21 to 23 vary in accordance with the permittivity K 2 , K 3 and K 4 of the fuel between their plates; output signals representative of these values of permittivity are supplied via lines 24 to 26 respectively to the computing unit 20. With reference now also to FIG. 2, the computing unit 20 is arranged to compute approximate values of the densities D K2 , D K3 , D K4 of fuel in the tanks 2, 3 and 4 by substituting the values K 2 , K 3 and K 4 of the permittivity respectively in the expression (I). The values K 2 , K 3 and K 4 of the permittivity of the fuel are also used to compensate for changes in permittivity affecting the capacitive probes 8 to 10. Fuel from the inlet pipe 1 is also supplied to a sensor unit 30 which is located at a point along the inlet pipe upstream from the fuel-tanks 2 to 4. The sensor unit 30 is so arranged that all the fuel (or a sample of all the fuel) supplied to the aircraft passes through the unit prior to being supplied to any of the tanks 2 to 4. The unit 30 includes a permittivity cell 31 which may be of a similar form to the cells 21 to 23 mounted in the tanks, and which is arranged to supply signals via line 32 to the computing unit 20 representative of the permittivity K 0 of the fuel supplied to the aircraft. The sensing unit 30 also includes a densitometer 33 that is arranged to supply signals representative of the fuel density D 0 via line 34 to the computing unit 20. The densitometer 33 may be of any of the suitable known forms, such as, for example, give an indication of density by measuring the position of a float, or the resistance to movement of a rotating paddle or a vibrating element (such as, a vibrating cylinder), or by detecting changes in optical properties of the fluid. The densitometer 33 may readily provide a measure of the density of fuel supplied to the aircraft which is accurate to within about 0.15%. The computing unit 20 also derives an approximate indication D K0 of the density of fuel supplied to the aircraft, using the expression (I) and substituting for K, the value K 0 derived by the permittivity cell 31. The density D K0 derived from the permittivity cell 31 using expression (I) is related to the actual density D 0 derived from the densitometer by the relationship: D 0 =D K0 F . . . (II) where F is a correction factor. This correction factor F is used to modify the approximate values D K2 , D K3 and D K4 of the densities derived from the permittivity cells 21, 22 and 23 so as thereby to give a more accurate measure of the densities. A more accurate measure could be derived simply by using a product of the approximate values D K2 to D K4 with the correction factor F. Since the permittivity cells 21 to 23 can measure permittivity to within about 0.2% and the densitometer 33 can measure density to within about 0.15%, an overall accuracy of (0.2 2 +0.15 2 )1/2 or 0.25% may be derived. As can be seen, therefore, this arrangement can give a substantial improvement on the 2% accuracy derived using the permittivity cells alone, without the expense of providing an individual densitometer for each tank. This simple use of the correction factor can be satisfactory where the fuel in each tank is the same and the variations in density are attributable solely to variations in temperature between the tanks. The accuracy is, however, severely reduced where different fuels are present in different tanks since the single densitometer enables a correction factor for only one particular fuel to be derived at any one time. In practice, prior to each refuelling, some tanks may be empty, some full, and others partly full. After refuelling with a different fuel the tanks will each have different mixtures of fuel. A more detailed consideration of the present invention will demonstrate how this problem is overcome. Since the sensor unit 30 is located along the inlet pipe 1 upstream of the tanks 2 to 4 it receives only fuel which is supplied to the aircraft at each refuelling and does not therefore provide an indication of the properties of any mixtures of fuel resulting from successive refuellings. Initially, assuming all the tanks 2 to 4 are empty, the same fuel is supplied to fill all the tanks, and the densitometer 33 and permittivity cell 31 of the sensor unit 30 supply signals D 01 and K 01 to the computing unit 20 in accordance with the density and permittivity respectively of this fuel. The computing unit 20 derives an approximate value D K01 of the density by substituting the value K 01 of the permittivity in the expression (I). The computing unit 20 then substitutes this approximate value D K01 and the value of density D 01 derived from the densitometer 33 into expression (II) to give: F.sub.1 =D.sub.01 /D.sub.K01 . . . (III) where F 1 is the correction factor for the first fuel and is the same for each of the tanks 2 to 4. This correction factor F 1 is used by the computing unit 20 in calculations of fuel quantity in the tanks 2 to 4 until such time as the aircraft should be next refuelled. At the next refuelling stop, some of the original fuel will have been expended and the levels in the tanks 2 to 4 will have fallen. The volume of original fuel still present in each tank is measured using the capacitance probes 8 to 10. For ease of understanding, only the behaviour of one tank 2 will be considered but it will be appreciated that the quantity of fuel in the other tanks may be determined in a similar manner. New fuel is supplied to the aircraft through the inlet pipe 1, the sensor unit 30 supplying signals indicative of its density D 02 and permittivity K 02 to the computing unit 20 which in turn derives a new correction factor F 2 for the new fuel. The new fuel is supplied to the tanks where it is mixed with the remaining original fuel. The correction factor F m for the mixture of fuel in tank 2 is given by the expression: F.sub.m =(V.sub.1 F.sub.1 +V.sub.2 F.sub.2)/(V.sub.1 +V.sub.2) . . . (IV) where V 1 is the volume of original fuel remaining in the tank 2; and V 2 is the volume of new fuel supplied to the tank 2. The total volume of fuel V T in the tank 2 after refuelling is given by: V.sub.T =V.sub.1 +V.sub.2 . . . (V) Removing V 2 from (IV) gives: F.sub.m =(F.sub.1 -F.sub.2)V.sub.1 /V.sub.T +F.sub.2 . . . (VI) The correction factor F m for the fuel mixture is computed by the computing unit 20 using expression (VI) and this correction factor is used, together with the approximate measure of density derived from the permittivity of the fuel mixture, to provide a measure of the density of the fuel mixture within tank 2. The correction factor F m is used by the computing unit 20 in calculations of the fuel quantity in the tank 2 until the aircraft is next refuelled. The value of the correction factor F m is stored in the computing unit 20 and is used in expression (VI) upon next refuelling to give: F.sub.m '=(F.sub.m -F.sub.3)V.sub.T '+F.sub.3 . . . (VII) where F m ' is the correction factor of the new mixture; F 3 is the correction factor of the fuel supplied at the next refuelling; V 3 is the volume of fuel remaining in tank 2 prior to next refuelling; and V T ' is the total volume of fuel after next refuelling. In this way, it is possible to derive a new correction factor for the fuel mixture upon every refuelling occasion from a knowledge of the volume of fuel before and after refuelling, the correction factor of the new fuel and the correction factor of the fuel in the tank prior to refuelling. It is important therefore that the value of the correction factor prior to refuelling is stored in a non-volatile memory, that is, a memory which retains its stored information even when it is not supplied with power. Thus, at the end of a flight, if the fuel-gauging system is turned off, it will retain knowledge of the correction factor for use when the aircraft is subsequently refuelled. It is not necessary to retain knowledge of fuel volume after the system has been switched off since refuelling would not normally occur until after the system had been switched on again, at which time the volume of fuel could be remeasured. As a precaution against erasure of the memory within which the correction factor is stored, the computing unit 20 is arranged to substitute a value of 1.0 if the stored value of the factor falls outside prescribed limits thereby indicating that erasure may have occurred. Initially, therefore, the system will function with the value of the fuel density being derived solely from the permittivity cells 21 to 23 in accordance with expression (I) and with an accuracy of only about 2%. Upon refuelling, however, the correction factor for the incoming fuel is employed in calculation of the density of the new mixture and the error in the value of the correction factor of fuel remaining in the tank is reduced in accordance with the ratio of the volume of new fuel supplied to the tank, to the volume of old fuel remaining in the tank. The sensor unit 30 may only be immersed in fuel when fuel is actually being supplied to the aircraft and, for this reason, it is arranged that the output signals from the sensor unit are only employed in calculation of the correction factors when refuelling is actually in progress. In practice, the volume of fuel in each of the tanks 2 to 4 is measured repeatedly many times a second, rather than continuously. If the fuel volume has increased by more than a prescribed percentage, the computing unit 20 concludes that refuelling is occurring and calculates the fuel correction factor for the incoming fuel from the outputs of the densitometer 33 and permittivity cell 31. When successive measurements of the volume of fuel in the tank show that refuelling has stopped--that is, when the volume measurements are the same as or less than preceding volume measurements--the new correction factor is employed in the calculation of fuel density until the next refuelling occurs. The computing unit 20 derives an indication of the mass of fuel M 2 in the tank 2 at any particular time in accordance with the expression: M.sub.2 =V.sub.T2 D.sub.K2 F.sub.2 . . . (VIII) where V T2 is the total volume of fuel in tank 2 at that time; D K2 is the value of density as derived from the permittivity using expression (I); and F 2 is the correction factor for the particular mixture in tank 2 at that time. The mass of fuel M 3 and M 4 in the other tanks 3 and 4 is similarly computed and added together to give a measure of the total mass of fuel on the aircraft. Signals representative of this total mass are supplied to a display unit 40 via line 41 and to a fuel-management unit 50 via line 51. If desired, separate indications of the amount of fuel in each tank could be provided on separate display units. It will be appreciated that various alternative arrangements for measuring the height of fuel in the tanks could be used in place of capacitive sensors. In this respect, optical, thermal, ultrasonic or other electrical sensors could be used. A flow chart illustrating operation of the system for fuel-tank 2 is shown in FIG. 2. For the purpose of this flow chart the correction factor used in calculation of the mass M of fuel is given the letter F, the correction factor derived from the sensing unit 30 is denoted F S , the correction factor of the fuel remaining in the tank prior to refuelling is denoted F R , and the volume of fuel remaining in the tank prior to refuelling is denoted V R . This gives, from expression (VI): F=(F.sub.R -F.sub.S)V.sub.R /V.sub.T +F.sub.S . . . (IX) At the start of operation of the method, the value V R would normally assume some random value. The first measure of the volume of fuel V T in the tank at start of operation might therefore be greater than V R in which case the computing unit 20 would conclude that refuelling was taking place, even if in reality no fuel has been added to the tank following the previous cessation of operation. The effect of this would be that the computing unit 20 would derive a new value of the correction factor from the sensor unit 30, even though this might not be immersed in fuel, and would thereby cause errors in the computation of fuel density. To avoid such errors arising, at the start of operation (stage 5) V R is put equal to V max , that is, the maximum volume of fuel that could be contained in the tank. On the first cycle or performance of the method, the actual volume V T of fuel present will be less than or equal to this maximum volume and the computing program will therefore go from stage 7 to stages 13 and 14, so as to replace V R by V T for the second cycle. On the second cycle, if the volume of fuel V T at the time of the second cycle is more than 5% greater than the volume of fuel V R at the time of the previous cycle the computing unit 20 concludes (at stage 7) that refuelling is taking place and the correction factor is therefore updated (during stages 8 to 11) in accordance with the density of the new fuel being added.
A system for indicating the mass of fuel in several fuel tanks of an aircraft has a capacitive depth sensor and a permittivity cell located in each tank. Signals from the sensors and cells are supplied to a computing unit which computes the volume of fuel in each tank and its approximate density. The system has a densitometer and another permittivity cell which receive a sample of all the fuel supplied to the tanks, and supply output signals to the computing unit. The computing unit derives a correction factor by comparing an approximate value of density derived from the other permittivity cell with a more accurate measure of density derived from the densitometer. The correction factor is used to correct the approximate values of density derived from the permittivity cell in each tank. A correction factor is calculated in respect of every batch of fuel supplied to the tanks and a combined correction factor is calculated for the mixture in each tank, from the volumes and respective correction factors of the constituent fuels.
Briefly describe the main idea outlined in the provided context.
[ "BACKGROUND OF THE INVENTION This invention relates to fluid-gauging systems and fluid-gauging methods.", "The invention is especially, but not exclusively, concerned with fuel-gauging systems for aircraft.", "Measurement of the quantity of fuel within an aircraft's fuel-tanks is commonly performed by means of one or more capacitive probes arranged for immersion in any fuel present.", "The capacitance of the probe varies in accordance with the depth of fuel in the tank, thereby enabling an indication of fuel level to be obtained.", "Changes in permittivity of fuel which would affect the capacitance of the probe can be compensated for by use of a permittivity cell (which may be in the form of a parallel-plate capacitor of open construction) mounted at the bottom of the fuel-tank, so as always to be immersed in any fuel present.", "An indication of volume may be obtained directly if the tank is of a regular shape, that is, if the volume of fuel present varies in a linear fashion with the depth of fuel.", "For irregularly shaped tanks the probe may be characterised, that is, the probe plates may be suitably-shaped such that the surface area of the plates covered by fuel varies in a non-linear fashion with depth but in a manner that is directly related to the volume of fuel present.", "Alternatively, the output of the probe may be supplied to a computer in which is stored a model of the fuel-tank from which can be obtained an indication of the volume with knowledge of the fuel depth.", "In many applications, such as, for example, in aircraft, it is necessary to have an indication of the fuel mass rather than its volume.", "Although the mass of fuel can be readily determined by measuring its density with some form of densitometer, the cost of densitometers capable of providing the high accuracy needed in some applications can be very high.", "Most modern aircraft are equipped with several fuel-tanks and, because of the variations in density between different fuels, such as might be supplied to different tanks during refuelling stops at different airports, it is necessary to obtain a measure of the density of each of the different fuels and fuel mixtures within the different tanks.", "The cost of providing a fuel-gauging system having a densitometer mounted in each of an aircraft's fuel-tanks will therefore be correspondingly high, and, in many cases prohibitive.", "To avoid the need to use densitometers, it has been proposed instead to measure the permittivity of fuel with a relatively simple and inexpensive capacitive permittivity cell and to derive the density from the permittivity using a relationship of the form: D K =(K-1)/0.763(0.7+0.2(K-1)) .", "(I) where D K is the density of the fuel;", "and K is the permittivity of the fuel.", "Since the permittivity cells can be relatively inexpensive, it is possible to mount a cell in every tank and thereby compensate for fuels of different densities.", "The above relationship, however, is only approximate;", "random variations from fuel to fuel mean that errors of up to about 2% can be experienced.", "In the future, with fuels derived from an increasing number of sources, it is likely that even greater errors may be experienced.", "Although a fuel-gauging system of such limited accuracy may be satisfactory in some cases, the need to carry more fuel than is absolutely necessary, in order to allow sufficient safety margin for inaccuracies in the system, will mean that the payload that can be carried by the aircraft must be correspondingly reduced.", "BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluid-gauging system and method that may be used to alleviate the above-mentioned difficulties.", "According to one aspect of the present invention there is provided a fluid-gauging system for use in providing a representation of the mass of fluid present in a plurality of reservoirs, the system including means for providing a representation of the volume of fluid present in each said reservoir, first means associated with each said reservoir for providing a first representation of the density of fluid in each said reservoir, second means for providing a second representation of the density of fluid, said second representation being more accurate than said first representation, and means for modifying each said first representation in accordance with said second representation so as thereby to obtain a more accurate representation of the density of fluid in each said reservoir.", "The second means providing the second density representation may receive a sample at least of all the fluid supplied to the reservoirs.", "The first means may include means located in each reservoir for providing a first representation of the permittivity of fluid in each reservoir, and means for deriving, from said first permittivity representations, said first density representations.", "The system may further include third means for providing in respect of fluid supplied to said reservoirs, a second permittivity representation, and means for deriving, from said second permittivity representation, a third density representation.", "The system may include means for comparing said second density representation with said third density representation so as to derive a correction factor therefrom for use in modifying each said first density representation.", "The system may be arranged to derive a first correction factor in respect of a first fluid supplied to said reservoirs, said first correction factor being stored in store means, the system being arranged to derive a second correction factor in respect of a second fluid supplied to said reservoirs, and a third correction factor in respect of each said reservoir in accordance with the volumes of said first and second fluids in each said reservoir and their respective correction factors, each said first density representation being modified by use of said third correction factor.", "According to another aspect of the present invention there is provided a method of providing an indication of the mass of fluid present in a plurality of reservoirs, said method including the steps of deriving a representation of the volume of fluid in each said reservoir, deriving a first representation of the density of fluid in each said reservoir, deriving a second representation of the density of fluid, said second density representation being more accurate than said first density representation, and modifying each said first density representation in accordance with said second density representation so as thereby to obtain a more accurate representation of the density of fluid in each said reservoir.", "A fuel-gauging system and method for an aircraft, in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of the system;", "FIG. 2 is a schematic representation of a part of the system of FIG. 1;", "and FIG. 3 is a flow chart indicating operation of the method and system.", "DETAILED DESCRIPTION With reference to FIG. 1, an inlet pipe 1 is connected to supply fuel to fuel-tanks 2, 3 and 4 (only three of which are shown in FIG. 1) mounted within the aircraft.", "Fuel is supplied to the aircraft engine (not shown) via outlet pipes 5, 6 and 7 extending from the bottom of each of the fuel-tanks 2, 3 and 4 respectively.", "Capacitive level probes 8 to 10 are mounted vertically within the tanks 2 to 4 and provide output signals C 2 , C 3 and C 4 respectively representative of the values of capacitance of the probes, which signals vary in accordance with fuel depths within the tanks.", "The signals C 2 , C 3 and C 4 are supplied via lines 11 to 13 to a computing unit 20 which derives a measure of the volume of fuel in each tank.", "A permittivity cell 21 to 23 is also mounted within each of the tanks 2 to 4 respectively.", "The cells 21 to 23 may each take the form of a simple parallel-plate capacitor of open construction that is mounted at the bottom of the fuel-tank so that it is always totally immersed in any fuel that may be present.", "The capacitances of the cells 21 to 23 vary in accordance with the permittivity K 2 , K 3 and K 4 of the fuel between their plates;", "output signals representative of these values of permittivity are supplied via lines 24 to 26 respectively to the computing unit 20.", "With reference now also to FIG. 2, the computing unit 20 is arranged to compute approximate values of the densities D K2 , D K3 , D K4 of fuel in the tanks 2, 3 and 4 by substituting the values K 2 , K 3 and K 4 of the permittivity respectively in the expression (I).", "The values K 2 , K 3 and K 4 of the permittivity of the fuel are also used to compensate for changes in permittivity affecting the capacitive probes 8 to 10.", "Fuel from the inlet pipe 1 is also supplied to a sensor unit 30 which is located at a point along the inlet pipe upstream from the fuel-tanks 2 to 4.", "The sensor unit 30 is so arranged that all the fuel (or a sample of all the fuel) supplied to the aircraft passes through the unit prior to being supplied to any of the tanks 2 to 4.", "The unit 30 includes a permittivity cell 31 which may be of a similar form to the cells 21 to 23 mounted in the tanks, and which is arranged to supply signals via line 32 to the computing unit 20 representative of the permittivity K 0 of the fuel supplied to the aircraft.", "The sensing unit 30 also includes a densitometer 33 that is arranged to supply signals representative of the fuel density D 0 via line 34 to the computing unit 20.", "The densitometer 33 may be of any of the suitable known forms, such as, for example, give an indication of density by measuring the position of a float, or the resistance to movement of a rotating paddle or a vibrating element (such as, a vibrating cylinder), or by detecting changes in optical properties of the fluid.", "The densitometer 33 may readily provide a measure of the density of fuel supplied to the aircraft which is accurate to within about 0.15%.", "The computing unit 20 also derives an approximate indication D K0 of the density of fuel supplied to the aircraft, using the expression (I) and substituting for K, the value K 0 derived by the permittivity cell 31.", "The density D K0 derived from the permittivity cell 31 using expression (I) is related to the actual density D 0 derived from the densitometer by the relationship: D 0 =D K0 F .", "(II) where F is a correction factor.", "This correction factor F is used to modify the approximate values D K2 , D K3 and D K4 of the densities derived from the permittivity cells 21, 22 and 23 so as thereby to give a more accurate measure of the densities.", "A more accurate measure could be derived simply by using a product of the approximate values D K2 to D K4 with the correction factor F. Since the permittivity cells 21 to 23 can measure permittivity to within about 0.2% and the densitometer 33 can measure density to within about 0.15%, an overall accuracy of (0.2 2 +0.15 2 )1/2 or 0.25% may be derived.", "As can be seen, therefore, this arrangement can give a substantial improvement on the 2% accuracy derived using the permittivity cells alone, without the expense of providing an individual densitometer for each tank.", "This simple use of the correction factor can be satisfactory where the fuel in each tank is the same and the variations in density are attributable solely to variations in temperature between the tanks.", "The accuracy is, however, severely reduced where different fuels are present in different tanks since the single densitometer enables a correction factor for only one particular fuel to be derived at any one time.", "In practice, prior to each refuelling, some tanks may be empty, some full, and others partly full.", "After refuelling with a different fuel the tanks will each have different mixtures of fuel.", "A more detailed consideration of the present invention will demonstrate how this problem is overcome.", "Since the sensor unit 30 is located along the inlet pipe 1 upstream of the tanks 2 to 4 it receives only fuel which is supplied to the aircraft at each refuelling and does not therefore provide an indication of the properties of any mixtures of fuel resulting from successive refuellings.", "Initially, assuming all the tanks 2 to 4 are empty, the same fuel is supplied to fill all the tanks, and the densitometer 33 and permittivity cell 31 of the sensor unit 30 supply signals D 01 and K 01 to the computing unit 20 in accordance with the density and permittivity respectively of this fuel.", "The computing unit 20 derives an approximate value D K01 of the density by substituting the value K 01 of the permittivity in the expression (I).", "The computing unit 20 then substitutes this approximate value D K01 and the value of density D 01 derived from the densitometer 33 into expression (II) to give: F.sub[.", "].1 =D.", "sub[.", "].01 /D.", "sub.", "K01 .", "(III) where F 1 is the correction factor for the first fuel and is the same for each of the tanks 2 to 4.", "This correction factor F 1 is used by the computing unit 20 in calculations of fuel quantity in the tanks 2 to 4 until such time as the aircraft should be next refuelled.", "At the next refuelling stop, some of the original fuel will have been expended and the levels in the tanks 2 to 4 will have fallen.", "The volume of original fuel still present in each tank is measured using the capacitance probes 8 to 10.", "For ease of understanding, only the behaviour of one tank 2 will be considered but it will be appreciated that the quantity of fuel in the other tanks may be determined in a similar manner.", "New fuel is supplied to the aircraft through the inlet pipe 1, the sensor unit 30 supplying signals indicative of its density D 02 and permittivity K 02 to the computing unit 20 which in turn derives a new correction factor F 2 for the new fuel.", "The new fuel is supplied to the tanks where it is mixed with the remaining original fuel.", "The correction factor F m for the mixture of fuel in tank 2 is given by the expression: F.sub.", "m =(V.", "sub[.", "].1 F.sub[.", "].1 +V.", "sub[.", "].2 F.sub[.", "].2)/(V.", "sub[.", "].1 +V.", "sub[.", "].2) .", "(IV) where V 1 is the volume of original fuel remaining in the tank 2;", "and V 2 is the volume of new fuel supplied to the tank 2.", "The total volume of fuel V T in the tank 2 after refuelling is given by: V.sub.", "T =V.", "sub[.", "].1 +V.", "sub[.", "].2 .", "(V) Removing V 2 from (IV) gives: F.sub.", "m =(F.", "sub[.", "].1 -F.", "sub[.", "].2)V.", "sub[.", "].1 /V.", "sub.", "T +F.", "sub[.", "].2 .", "(VI) The correction factor F m for the fuel mixture is computed by the computing unit 20 using expression (VI) and this correction factor is used, together with the approximate measure of density derived from the permittivity of the fuel mixture, to provide a measure of the density of the fuel mixture within tank 2.", "The correction factor F m is used by the computing unit 20 in calculations of the fuel quantity in the tank 2 until the aircraft is next refuelled.", "The value of the correction factor F m is stored in the computing unit 20 and is used in expression (VI) upon next refuelling to give: F.sub.", "m '=(F.", "sub.", "m -F.", "sub[.", "].3)V.", "sub.", "T '+F.", "sub[.", "].3 .", "(VII) where F m '", "is the correction factor of the new mixture;", "F 3 is the correction factor of the fuel supplied at the next refuelling;", "V 3 is the volume of fuel remaining in tank 2 prior to next refuelling;", "and V T '", "is the total volume of fuel after next refuelling.", "In this way, it is possible to derive a new correction factor for the fuel mixture upon every refuelling occasion from a knowledge of the volume of fuel before and after refuelling, the correction factor of the new fuel and the correction factor of the fuel in the tank prior to refuelling.", "It is important therefore that the value of the correction factor prior to refuelling is stored in a non-volatile memory, that is, a memory which retains its stored information even when it is not supplied with power.", "Thus, at the end of a flight, if the fuel-gauging system is turned off, it will retain knowledge of the correction factor for use when the aircraft is subsequently refuelled.", "It is not necessary to retain knowledge of fuel volume after the system has been switched off since refuelling would not normally occur until after the system had been switched on again, at which time the volume of fuel could be remeasured.", "As a precaution against erasure of the memory within which the correction factor is stored, the computing unit 20 is arranged to substitute a value of 1.0 if the stored value of the factor falls outside prescribed limits thereby indicating that erasure may have occurred.", "Initially, therefore, the system will function with the value of the fuel density being derived solely from the permittivity cells 21 to 23 in accordance with expression (I) and with an accuracy of only about 2%.", "Upon refuelling, however, the correction factor for the incoming fuel is employed in calculation of the density of the new mixture and the error in the value of the correction factor of fuel remaining in the tank is reduced in accordance with the ratio of the volume of new fuel supplied to the tank, to the volume of old fuel remaining in the tank.", "The sensor unit 30 may only be immersed in fuel when fuel is actually being supplied to the aircraft and, for this reason, it is arranged that the output signals from the sensor unit are only employed in calculation of the correction factors when refuelling is actually in progress.", "In practice, the volume of fuel in each of the tanks 2 to 4 is measured repeatedly many times a second, rather than continuously.", "If the fuel volume has increased by more than a prescribed percentage, the computing unit 20 concludes that refuelling is occurring and calculates the fuel correction factor for the incoming fuel from the outputs of the densitometer 33 and permittivity cell 31.", "When successive measurements of the volume of fuel in the tank show that refuelling has stopped--that is, when the volume measurements are the same as or less than preceding volume measurements--the new correction factor is employed in the calculation of fuel density until the next refuelling occurs.", "The computing unit 20 derives an indication of the mass of fuel M 2 in the tank 2 at any particular time in accordance with the expression: M.sub[.", "].2 =V.", "sub.", "T2 D.sub.", "K2 F.sub[.", "].2 .", "(VIII) where V T2 is the total volume of fuel in tank 2 at that time;", "D K2 is the value of density as derived from the permittivity using expression (I);", "and F 2 is the correction factor for the particular mixture in tank 2 at that time.", "The mass of fuel M 3 and M 4 in the other tanks 3 and 4 is similarly computed and added together to give a measure of the total mass of fuel on the aircraft.", "Signals representative of this total mass are supplied to a display unit 40 via line 41 and to a fuel-management unit 50 via line 51.", "If desired, separate indications of the amount of fuel in each tank could be provided on separate display units.", "It will be appreciated that various alternative arrangements for measuring the height of fuel in the tanks could be used in place of capacitive sensors.", "In this respect, optical, thermal, ultrasonic or other electrical sensors could be used.", "A flow chart illustrating operation of the system for fuel-tank 2 is shown in FIG. 2. For the purpose of this flow chart the correction factor used in calculation of the mass M of fuel is given the letter F, the correction factor derived from the sensing unit 30 is denoted F S , the correction factor of the fuel remaining in the tank prior to refuelling is denoted F R , and the volume of fuel remaining in the tank prior to refuelling is denoted V R .", "This gives, from expression (VI): F=(F.", "sub.", "R -F.", "sub.", "S)V.", "sub.", "R /V.", "sub.", "T +F.", "sub.", "S .", "(IX) At the start of operation of the method, the value V R would normally assume some random value.", "The first measure of the volume of fuel V T in the tank at start of operation might therefore be greater than V R in which case the computing unit 20 would conclude that refuelling was taking place, even if in reality no fuel has been added to the tank following the previous cessation of operation.", "The effect of this would be that the computing unit 20 would derive a new value of the correction factor from the sensor unit 30, even though this might not be immersed in fuel, and would thereby cause errors in the computation of fuel density.", "To avoid such errors arising, at the start of operation (stage 5) V R is put equal to V max , that is, the maximum volume of fuel that could be contained in the tank.", "On the first cycle or performance of the method, the actual volume V T of fuel present will be less than or equal to this maximum volume and the computing program will therefore go from stage 7 to stages 13 and 14, so as to replace V R by V T for the second cycle.", "On the second cycle, if the volume of fuel V T at the time of the second cycle is more than 5% greater than the volume of fuel V R at the time of the previous cycle the computing unit 20 concludes (at stage 7) that refuelling is taking place and the correction factor is therefore updated (during stages 8 to 11) in accordance with the density of the new fuel being added." ]
TECHNICAL FIELD [0001] The present invention relates generally to paving materials, and in particular, to an apparatus for determining liquid absorption by aggregate or binder-aggregate mixtures. The method and apparatus aids in determining the saturated surface dry state of such mixtures as an aid in designing effective compositions. BACKGROUND OF THE INVENTION [0002] Most paved surfaces, including roadways, consist of a plurality of materials and layers. Typically, these mixtures include a binder such as cement or asphalt-cement, and a plurality of different aggregates composed of rocks, stones, or other materials. These paving mixtures are described as “compacted mixtures.” [0003] The composition of these compacted mixtures is an important factor in the service life of the construction project. In order to predict a certain minimum service life, most paving projects require conformance to predetermined minimum build specifications or standards. Among these standards are requirements relating to the capacity of the aggregate or binder-aggregate material to absorb fluid. To properly design a paving mix, by way of example and not limitation, asphalt paving mixes, the proper amount of binder must be added to a given amount of aggregate in order to maintain a mixture which will result in a strong and durable paved surface. If there is too much binder, that is for example, too much asphalt-cement in an asphalt-aggregate paving mix, the paved surface will be soft and excessive wear and rutting will result. If there is not enough binder in the composition, the paved surface will be brittle and will crumble or break apart, particularly under loading stresses associated with vehicular traffic. [0004] A particularly difficult problem in designing appropriate mixtures lies in the fact that aggregates, such as rock and stone, are not hydraulically neutral agents. That is, they have the ability to both absorb fluid, such as binder and water, into their interior matrix and to adsorb fluid onto their surfaces. When binder, such as asphalt-cement, is absorbed internally into a porous aggregate, that absorbed binder does not contribute to the effective volume of the asphalt mix. In order to account for this absorbed binder, additional binder must be added to the mix. The need to add such compensatory binder can lead to incorrect formulation of the mix. The measurement of the binder absorbed by the aggregate which does not contribute to the volume of the asphalt mix is the percent absorption (PA), by weight, of water absorbed into the aggregate relative to the weigh of the aggregate itself. [0005] In general, the procedure for testing aggregate for PA involves saturating the internal matrix of the aggregate, and then drying the aggregate to determine the amount of fluid that has been internally absorbed. As a first step, a sample of dry aggregate is prepared to a condition where the internal voids are saturated by water, but the external surface of the aggregate is dry. This condition is known as the saturated surface dry (SSD) state. The sample is then dried completely in an oven, and weighed again in the dry state. The difference between the SSD and dry weights, divided by the dry weight, converted to a percentage, is the PA. [0006] Additionally, asphalt-aggregate mixes are commonly tested for specific gravity and density using what is usually denominated the “Rice test.” Such a test also requires surface drying of the sample before testing. [0007] Besides the necessity of thoroughly saturating the tested material to establish a baseline for fluid absorption, an obvious difficulty in this process is drying the surface of the material after saturation to the point where the surface of the material is dry, but where fluid is not extracted from the internal matrix. [0008] One method of preparing a sample of material to the SSD condition is what is known as the “towel dry” method. In this method, totally saturated material, generally aggregate, is lightly hand dried with paper towels to just the point where the aggregate surface is dry. This technique is best used for larger aggregate such as that for concrete. Obviously, it suffers from the necessity for hand labor and the crude estimation of surface drying that must be made. [0009] Another method is a “slump test,” used for both concrete and asphalt aggregates, where a cone of saturated aggregate is allowed to slump following removal of a cone shaped form. Saturated aggregate will tend to retain a cone shape, while surface dried aggregate will tend to slump. This method suffers from observational error induced by the subjective judgment of slump made by technicians, and for differences in various aggregates' tendency to slump based on factors other than surface moisture, such as angularity or fineness of the aggregate. [0010] There are constraints on the methods that maybe used for drying the aggregate surface, in order to prevent more than a negligible amount of internal fluid being driven off before the SSD weight can be calculated. Foremost among these is the avoidance of external heat in the drying, as such heat tends to drive fluid from the internal matrix to the surface of the aggregate. Additionally, heat is avoided during drying of asphalt-aggregate mixtures to avoid thermal effects on the asphalt binder. [0011] Determination of the SSD state of an asphalt-aggregate mixture is also critical in measuring the percentage of air voids in a compacted mixture, an important parameter for estimating wear effects and service life of a paving product. [0012] First the bulk specific gravity (G mb ) of a compacted asphalt mixture is determined. The procedure requires that the compacted mix be weighed in air, submerged, and in the SSD state, and is determined by the following equation: G mb =A /( B−C ) [0013] Where: [0014] G mb =Bulk specific gravity of the collected specimen [0015] A=Oven dry mass (g) [0016] B=SSD mass (g) [0017] C=Submerged mass (g) [0018] The bulk specific gravity (G mb ) can then be employed in a standard test method to assess fluid absorption in asphalt-aggregate mixtures in ASTM 2041, known as “Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures Dry Back Process.” For the Rice test, a sample of the mixture is broken up into a voidless mass of particles less than 4.75 mm (0.25 in.) in size. The sample is placed in a calibrated container. The weight and volume of the voidless mix are then used to calculate the maximum specific gravity as shown in the following equation: G mm =A /( A−C ) [0019] Where: [0020] G mm =Theoretical maximum specific gravity [0021] A=Mass of oven dry sample in air, (g) [0022] C=Mass of water displaced by sample at 25° C. (77° F.), (g) [0023] The bulk specific gravity of the collected specimen (G mb ) and the theoretical maximum specific gravity (G mm ) can then be used to calculate the air void content of the compacted material, according to the following equation: V a =( 1−( G mb −G mm ))×100 [0024] Where: [0025] V a =Air voids in the compacted mix, percent [0026] G mb =Bulk specific gravity of the compacted mix [0027] G mm =Theoretical maximum specific gravity of the mix [0028] The derivation of these measurements requires an efficient means of determining the saturated surface dry (SSD) state of an aggregate or mixture. Typically, an ad hoc drying method is used in laboratories, similar to the arrangement seen in FIG. 1, such as placing the saturated material in a drying sieve (S), and then blowing air from a household fan (F) through the aggregate. The sieve (S) must be propped up upon some auxiliary device (P), generally another sieve, to permit air to flow through the sieve (S) and exit between the sieve (S) and the work surface (WS). In this configuration an extension device (E), often yet another sieve, must be used to provide some space between the fan (F) and the contents of the sieve (S). To achieve a reasonable seal and volume of air blown through the material, the fan is often set atop the drying sieve, with a prop underneath the sieve to allow air circulation, a cumbersome solution that sometimes leads to spillage of the pan contents and the need to begin the test anew. The fan is removed periodically to stir the material to assist in drying, and at any point the fan may fall off of the sieve, in particular as the designs of many fans do not allow for a symmetrical weight distribution on the sieve, again as seen in FIG. 1. The weight of the material, subtracting the tare weight of the drying sieve, approximates the SSD weight when successive weighings of the material vary by no more than 0.05%. [0029] Because of the inefficiency of a fan perched atop the sieve, drying time is often excessive. For example, a typical 1500-2000 gram sample takes approximately two hours, or more, to dry to the level upon with testing for the approach of SSD weigh can begin. The need to periodically remove the fan, stir the sieve contents, and repeatedly weigh the sieve consumes an inordinate amount of technician time and increases the possibility of error. [0030] What the art has needed is a drying apparatus that is capable of air drying the surface of mixtures to be tested, without the application of external heat, that is simple, inexpensive, easy to use, and, most importantly, fast. The apparatus should be stable and resist inadvertent spilling of the material while drying. Lastly, the material must be easily and reliably removable from the drying apparatus so that successive weighings can be carried out. Optimally, in some embodiments the drying device may be equipped to automatically perform the weighing operations. The instant invention satisfies these needs. SUMMARY OF INVENTION [0031] In its most general configuration, the present invention advances the state of the art with a variety of new capabilities and overcomes many of the shortcomings of prior devices in new and novel ways. In its most general sense, the present invention overcomes the shortcomings and limitations of the prior art in any of a number of generally effective configurations. The instant invention demonstrates such capabilities and overcomes many of the shortcomings of prior methods in new and novel ways, thereby reducing drying time by as much as 50% over conventional methods. In one of the simplest configurations, the apparatus incorporates a means for drying the surface of material in at least one drying sieve. The apparatus includes a housing, at least one discharge opening, a fan assembly within the housing, and an activation device to control the operation of the fan assembly. The top surface of the housing has at least one sieve opening to cooperate with at least one sieve to permit fluid communication between the housing interior space and the surrounding atmosphere. The at least one discharge opening is formed in the housing fluidly connecting the interior space of the housing with the surrounding atmosphere. The fan assembly is oriented to draw air from the surrounding atmosphere through the mixture in the at least one sieve and the at least one sieve opening and to discharge air through the at least one discharge opening to the surrounding atmosphere. Lastly, the activation device controls the operation of the fan assembly. [0032] The housing may be of virtually any shape than defines an interior space and may include at least one drain hole formed in the housing bottom surface to permit fluid that may accumulate in the housing to drain from the housing. The bottom surface may be formed to pitch toward the at least one drain hole. The housing may be constructed of virtually any material, including coated materials. The housing may be elevated from an external surface by at least one support device, which may be as simple as fixed legs, or may include more advanced adjustability and rotational features. [0033] The at least one discharge opening of the fan assembly may be located on any of the surfaces of the enclosure and may be fitted with various accessories, such as a safety screen, sound attenuator, or exhaust ductwork. [0034] In one particular embodiment, the fan assembly consists of a housed fan having a fan housing, a fan wheel, and a motor. Alternative embodiments may incorporate a plurality of fans. The fan assembly may be mounted in the housing in a number of ways, such as rigidly attached to the housing, or mounted to the housing with a vibration isolation system. [0035] The apparatus includes the activation device for controlling the operation of the fan assembly. Such activation device may be as simple as a plug style connector to cooperate with a common electrical connector, or may involve more complex controls, such as electronic controls or variable speed drive controls. Further embodiments may include a weight measuring system having at least one weight sensor and at least one display device. The at least one weight sensor may be formed as a sieve receiver adapted to receive and releasably hold the sieve over the sieve opening, or may include multiple sensors to cooperate with the sieve, or may be part of the at least one support device. Having the weight sensor as part of the at least one support device would be particularly useful in the single sieve opening embodiment, as the fan assembly would not have to be turned off during the reading since the at least one weight sensor will be measuring the weight of the entire apparatus rather than just the sieve and its contents. [0036] A control module may be adapted to receive data from the weight measuring system and at least one input device. The at least one input device may be any number of external devices such as a keyboard, or may include an input device built into the control module. The control module may then perform calculations, and display data on one at least one display device. The control module may also include memory to retain the input and output data. The calculations performed may include bulk specific gravity of the compacted specimen, the theoretical maximum specific gravity, and the air void percentage in the compacted mix, according to the equations seen above. Further, the control device may incorporate the function of the activation device in controlling the operation of the fan assembly. Additionally, the control module may be adapted to transmit data to at least one printer, either external to the apparatus or integral to the control module. [0037] These variations, modifications, alternatives, and alterations of the various preferred embodiments, arrangements, and configurations may be used alone or in combination with one another as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0038] Without limiting the scope of the present invention as claimed below and referring now to the drawings and figures: [0039] [0039]FIG. 1 shows a prior art setup for drying the surface of aggregate, in side elevation view, not to scale; [0040] [0040]FIG. 2 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale; [0041] [0041]FIG. 3 shows the apparatus of FIG. 1 in top plan view, not to scale; [0042] [0042]FIG. 4 shows the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale; [0043] [0043]FIG. 5 shows a variation of the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale; [0044] [0044]FIG. 6 shows a variation of the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale; [0045] [0045]FIG. 7 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale; [0046] [0046]FIG. 8 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale; and [0047] [0047]FIG. 9 shows a variation of the apparatus of FIG. 1 in top plan view, not to scale. DETAILED DESCRIPTION OF THE INVENTION [0048] The apparatus for drying the surface of aggregate of the instant invention enables a significant advance in the state of the art. The preferred embodiments of the apparatus accomplish this by new and novel arrangements of elements and methods that are configured in unique and novel ways and which demonstrate previously unavailable but preferred and desirable capabilities. [0049] The detailed description set forth below in connection with the drawings is intended merely as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention. In its simplest form the apparatus for drying the surface of aggregate in at least one sieve S incorporates a housing 100 , at least one discharge opening 170 , a fan assembly 200 , and an activation device 400 to control the operation of the fan assembly 200 , as seen in FIG. 2. The housing 100 has an interior space defined by at least one top surface 110 , at least one bottom surface 120 , and at least one side surface. The at least one top surface 110 is formed to have at least one sieve opening 180 of a size and configuration to cooperate with the at least one sieve S and to permit fluid communication between the housing interior space and the surrounding atmosphere, illustrated best in FIG. 3. The at least one discharge opening 170 is formed in the housing 100 thereby fluidly connecting the interior space of the housing with the surrounding atmosphere. The fan assembly 200 is positioned within the housing 100 and oriented to draw air from the surrounding atmosphere through the aggregate, the at least one sieve S, and the at least one sieve opening 180 , seen in FIG. 4, and discharge air through the at least one discharge opening 170 to the surrounding atmosphere. Lastly, the activation device 400 controls the operation of the fan assembly 200 . [0050] Referring again to FIG. 2, in one particular embodiment, the housing 100 further includes a front surface 130 , a back surface 140 , a left side surface 160 , and a right side surface 150 , thereby defining the interior space. In this illustrative embodiment, the at least one sieve opening 180 is approximately twelve inches in diameter to cooperate with the sieve size commonly used in an aggregate testing laboratory, but it may be any shape or size. Further, the housing 100 may include any number of sieve openings 180 . [0051] A further variation of the apparatus includes at least one drain hole 190 formed in the housing bottom surface 120 to permit fluid communication between the housing interior space and the surrounding atmosphere, as illustrated in FIG. 5 and FIG. 6. Therefore, any moisture that may accumulate in the housing 100 may be permitted to drain from the housing 100 , reducing the health risks associated with stagnant water. Further, the bottom surface may be formed to pitch toward the at least one drain hole. [0052] The housing 100 may be constructed of virtually any material, including, but not limited to, sheet metal, plastic, wood, and various composites. The material of construction may further be coated with any number of commercially available coatings to perform such functions as inhibiting corrosion as well as inhibiting microbial growth, among many others. [0053] At least one support device 300 may be attached to the enclosure 100 to elevate the bottom surface 120 from an external surface, as seen in FIG. 5. The at least one support device 300 may be as simple as fixed legs, or may include more advanced adjustability and rotational features. [0054] The at least one discharge opening 170 may be located on any of the surfaces of the enclosure. Just one configuration, that of top surface discharge, is illustrated in the figures. The at least one discharge opening 180 may be outfitted with any number of accessories. As one with skill in the art will appreciate, the at least one discharge opening 180 may be outfitted with a safety screen to prevent objects from coming in contact with the fan assembly 200 . Further, the at least one discharge opening 170 may be formed with a duct connection point so that the discharge air may be ducted outside, or other discharge location. Additionally, the at least one discharge opening 170 may incorporate a sound attenuator to minimize the transmission of noise from the discharge opening. The at least one discharge opening 170 size may vary with the airflow of the fan assembly 200 and may be configured in any shape and size. [0055] The fan assembly 200 may incorporate air movement devices in virtually any form. In one particular embodiment, the fan assembly consists 200 of a housed fan having a fan housing 220 , a fan wheel 210 rotably and releasable housed in the fan housing, and a motor 230 rotably and releasably joined to the fan wheel 210 , as seen in FIG. 4. Such a double inlet centrifugal fan may be either direct drive, or belt drive as seen in FIG. 6. In the belt drive embodiment the motor 230 and the fan wheel 210 are rotably and releasably coupled by at least one belt 240 . Alternative embodiments may incorporate a plurality of fans within the housing 100 . [0056] The fan assembly 200 may be mounted in the housing 100 in a number of ways. For instance, the fan assembly 200 may be rigidly attached to the housing 100 . Alternatively, the fan assembly 200 may be mounted to the housing 100 with a vibration isolation system 250 , as seen in FIG. 6. Such vibration isolation system 250 may include an inertia base and a flexible connection at the interface of the fan housing and the at least one discharge opening. Further, the fan assembly 200 may be suspended within the housing 100 with suspension type vibration isolators. [0057] The apparatus includes the activation device 400 for controlling the operation of the fan assembly 200 . Such activation device 400 may be as simple as a plug style connector to cooperate with a common electrical connector, or may involve more complex controls. As illustrated in FIG. 2, the activation device 400 may be a switch. Alternatively, as will be seen later, the activation device 400 may consists of electronic controls specifying the start and stop of the fan assembly 200 . Similarly, the activation device 400 may incorporate more advanced controls such as variable speed drives to control fan activation, deactivation, and speed. [0058] Further embodiments may include a weight measuring system 600 having at least one weight sensor 610 and at least one display device 620 , as seen in FIG. 8. The at least one weight sensor 610 may be formed as a sieve receiver adapted to receive and releasably hold the sieve S over the sieve opening 180 , as illustrated on the leftmost opening of FIG. 8. Alternatively, the at least one weight sensor 610 may include multiple sensors to cooperate with the sieve S, as illustrated in the rightmost opening of FIG. 8. The at least one display device 620 receives data from the at least one weight sensor 610 and computes a weight associated with the data to be displayed on the at least one display device 620 . The weight measurement system 600 may include electronic memory to store and display many weight readings during the process of drying the surface of the aggregate, as well as timing features. The fan system 200 would have to be off while the weight measurement readings were taken so that the negative pressure acting on the interior space, and therefore the sieve S, does not to affect such readings. As one with skill in the art will recognize, a timing/sampling circuit may be incorporated into the weight measurement system 600 such that weight measurements may occur at predetermined intervals and such that the fan system 200 is disabled during such readings, when required. [0059] In a further embodiment, the at least one support device 300 may incorporate the at least one weight sensor 610 . This would be particularly useful in the single sieve opening 180 embodiment illustrated in FIG. 9. In such an embodiment the fan assembly 200 would not have to be turned off during the reading since the at least one weight sensor 610 will be measuring the weight of the entire apparatus rather than just the sieve S and its contents. [0060] Yet another embodiment may include a control module 500 adapted to receive data from the weight measuring system 600 and at least one input device 510 . The at least one input device 510 may be any number of external devices such as a keyboard, or may include an input device 510 built into the control module 500 such as that shown in FIG. 7. The control module 500 may then perform calculations, and display data on one at least one display device 520 . The control module 500 may also include memory to retain the input and output data. The calculations performed may include bulk specific gravity of the compacted specimen, the theoretical maximum specific gravity, and the air void percentage in the compacted mix, according to the equations seen above. Further, the control device 500 may incorporate the function of the activation device 400 in controlling the operation of the fan assembly 200 . Additionally, the control module 500 may be adapted to transmit data to at least one printer 530 , either external to the apparatus or integral to the control module. [0061] Numerous alterations, modifications, and variations of the preferred embodiments disclosed herein will be apparent to those skilled in the art and they are all anticipated and contemplated to be within the spirit and scope of the instant invention. For example, although specific embodiments have been described in detail, those with skill in the art will understand that the preceding embodiments and variations can be modified to incorporate various types of substitute and or additional or alternative materials, relative arrangement of elements, and dimensional configurations. Accordingly, even though only few variations of the present invention are described herein, it is to be understood that the practice of such additional modifications and variations and the equivalents thereof, are within the spirit and scope of the invention as defined in the following claims. [0062] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed.
An apparatus for the drying of aggregate and aggregate-binder mixtures includes a housing containing a fan within a housing that pulls air through various materials held in a drying sieve, or multiple drying sieves, and then exhausts the air to the ambient environment. The apparatus is particularly useful in determining the saturated surface dry state of materials which is an important factor in various testing procedures. The apparatus may include activation means, such as switches and controls, and may incorporate weight sensors to aid in determining the drying state of the material. Various input, output, memory, and display functions are provided to allow calculations and display of observed and calculated indicia.
Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function.
[ "TECHNICAL FIELD [0001] The present invention relates generally to paving materials, and in particular, to an apparatus for determining liquid absorption by aggregate or binder-aggregate mixtures.", "The method and apparatus aids in determining the saturated surface dry state of such mixtures as an aid in designing effective compositions.", "BACKGROUND OF THE INVENTION [0002] Most paved surfaces, including roadways, consist of a plurality of materials and layers.", "Typically, these mixtures include a binder such as cement or asphalt-cement, and a plurality of different aggregates composed of rocks, stones, or other materials.", "These paving mixtures are described as “compacted mixtures.”", "[0003] The composition of these compacted mixtures is an important factor in the service life of the construction project.", "In order to predict a certain minimum service life, most paving projects require conformance to predetermined minimum build specifications or standards.", "Among these standards are requirements relating to the capacity of the aggregate or binder-aggregate material to absorb fluid.", "To properly design a paving mix, by way of example and not limitation, asphalt paving mixes, the proper amount of binder must be added to a given amount of aggregate in order to maintain a mixture which will result in a strong and durable paved surface.", "If there is too much binder, that is for example, too much asphalt-cement in an asphalt-aggregate paving mix, the paved surface will be soft and excessive wear and rutting will result.", "If there is not enough binder in the composition, the paved surface will be brittle and will crumble or break apart, particularly under loading stresses associated with vehicular traffic.", "[0004] A particularly difficult problem in designing appropriate mixtures lies in the fact that aggregates, such as rock and stone, are not hydraulically neutral agents.", "That is, they have the ability to both absorb fluid, such as binder and water, into their interior matrix and to adsorb fluid onto their surfaces.", "When binder, such as asphalt-cement, is absorbed internally into a porous aggregate, that absorbed binder does not contribute to the effective volume of the asphalt mix.", "In order to account for this absorbed binder, additional binder must be added to the mix.", "The need to add such compensatory binder can lead to incorrect formulation of the mix.", "The measurement of the binder absorbed by the aggregate which does not contribute to the volume of the asphalt mix is the percent absorption (PA), by weight, of water absorbed into the aggregate relative to the weigh of the aggregate itself.", "[0005] In general, the procedure for testing aggregate for PA involves saturating the internal matrix of the aggregate, and then drying the aggregate to determine the amount of fluid that has been internally absorbed.", "As a first step, a sample of dry aggregate is prepared to a condition where the internal voids are saturated by water, but the external surface of the aggregate is dry.", "This condition is known as the saturated surface dry (SSD) state.", "The sample is then dried completely in an oven, and weighed again in the dry state.", "The difference between the SSD and dry weights, divided by the dry weight, converted to a percentage, is the PA.", "[0006] Additionally, asphalt-aggregate mixes are commonly tested for specific gravity and density using what is usually denominated the “Rice test.”", "Such a test also requires surface drying of the sample before testing.", "[0007] Besides the necessity of thoroughly saturating the tested material to establish a baseline for fluid absorption, an obvious difficulty in this process is drying the surface of the material after saturation to the point where the surface of the material is dry, but where fluid is not extracted from the internal matrix.", "[0008] One method of preparing a sample of material to the SSD condition is what is known as the “towel dry”", "method.", "In this method, totally saturated material, generally aggregate, is lightly hand dried with paper towels to just the point where the aggregate surface is dry.", "This technique is best used for larger aggregate such as that for concrete.", "Obviously, it suffers from the necessity for hand labor and the crude estimation of surface drying that must be made.", "[0009] Another method is a “slump test,” used for both concrete and asphalt aggregates, where a cone of saturated aggregate is allowed to slump following removal of a cone shaped form.", "Saturated aggregate will tend to retain a cone shape, while surface dried aggregate will tend to slump.", "This method suffers from observational error induced by the subjective judgment of slump made by technicians, and for differences in various aggregates'", "tendency to slump based on factors other than surface moisture, such as angularity or fineness of the aggregate.", "[0010] There are constraints on the methods that maybe used for drying the aggregate surface, in order to prevent more than a negligible amount of internal fluid being driven off before the SSD weight can be calculated.", "Foremost among these is the avoidance of external heat in the drying, as such heat tends to drive fluid from the internal matrix to the surface of the aggregate.", "Additionally, heat is avoided during drying of asphalt-aggregate mixtures to avoid thermal effects on the asphalt binder.", "[0011] Determination of the SSD state of an asphalt-aggregate mixture is also critical in measuring the percentage of air voids in a compacted mixture, an important parameter for estimating wear effects and service life of a paving product.", "[0012] First the bulk specific gravity (G mb ) of a compacted asphalt mixture is determined.", "The procedure requires that the compacted mix be weighed in air, submerged, and in the SSD state, and is determined by the following equation: G mb =A /( B−C ) [0013] Where: [0014] G mb =Bulk specific gravity of the collected specimen [0015] A=Oven dry mass (g) [0016] B=SSD mass (g) [0017] C=Submerged mass (g) [0018] The bulk specific gravity (G mb ) can then be employed in a standard test method to assess fluid absorption in asphalt-aggregate mixtures in ASTM 2041, known as “Theoretical Maximum Specific Gravity and Density of Bituminous Paving Mixtures Dry Back Process.”", "For the Rice test, a sample of the mixture is broken up into a voidless mass of particles less than 4.75 mm (0.25 in.) in size.", "The sample is placed in a calibrated container.", "The weight and volume of the voidless mix are then used to calculate the maximum specific gravity as shown in the following equation: G mm =A /( A−C ) [0019] Where: [0020] G mm =Theoretical maximum specific gravity [0021] A=Mass of oven dry sample in air, (g) [0022] C=Mass of water displaced by sample at 25° C. (77° F.), (g) [0023] The bulk specific gravity of the collected specimen (G mb ) and the theoretical maximum specific gravity (G mm ) can then be used to calculate the air void content of the compacted material, according to the following equation: V a =( 1−( G mb −G mm ))×100 [0024] Where: [0025] V a =Air voids in the compacted mix, percent [0026] G mb =Bulk specific gravity of the compacted mix [0027] G mm =Theoretical maximum specific gravity of the mix [0028] The derivation of these measurements requires an efficient means of determining the saturated surface dry (SSD) state of an aggregate or mixture.", "Typically, an ad hoc drying method is used in laboratories, similar to the arrangement seen in FIG. 1, such as placing the saturated material in a drying sieve (S), and then blowing air from a household fan (F) through the aggregate.", "The sieve (S) must be propped up upon some auxiliary device (P), generally another sieve, to permit air to flow through the sieve (S) and exit between the sieve (S) and the work surface (WS).", "In this configuration an extension device (E), often yet another sieve, must be used to provide some space between the fan (F) and the contents of the sieve (S).", "To achieve a reasonable seal and volume of air blown through the material, the fan is often set atop the drying sieve, with a prop underneath the sieve to allow air circulation, a cumbersome solution that sometimes leads to spillage of the pan contents and the need to begin the test anew.", "The fan is removed periodically to stir the material to assist in drying, and at any point the fan may fall off of the sieve, in particular as the designs of many fans do not allow for a symmetrical weight distribution on the sieve, again as seen in FIG. 1. The weight of the material, subtracting the tare weight of the drying sieve, approximates the SSD weight when successive weighings of the material vary by no more than 0.05%.", "[0029] Because of the inefficiency of a fan perched atop the sieve, drying time is often excessive.", "For example, a typical 1500-2000 gram sample takes approximately two hours, or more, to dry to the level upon with testing for the approach of SSD weigh can begin.", "The need to periodically remove the fan, stir the sieve contents, and repeatedly weigh the sieve consumes an inordinate amount of technician time and increases the possibility of error.", "[0030] What the art has needed is a drying apparatus that is capable of air drying the surface of mixtures to be tested, without the application of external heat, that is simple, inexpensive, easy to use, and, most importantly, fast.", "The apparatus should be stable and resist inadvertent spilling of the material while drying.", "Lastly, the material must be easily and reliably removable from the drying apparatus so that successive weighings can be carried out.", "Optimally, in some embodiments the drying device may be equipped to automatically perform the weighing operations.", "The instant invention satisfies these needs.", "SUMMARY OF INVENTION [0031] In its most general configuration, the present invention advances the state of the art with a variety of new capabilities and overcomes many of the shortcomings of prior devices in new and novel ways.", "In its most general sense, the present invention overcomes the shortcomings and limitations of the prior art in any of a number of generally effective configurations.", "The instant invention demonstrates such capabilities and overcomes many of the shortcomings of prior methods in new and novel ways, thereby reducing drying time by as much as 50% over conventional methods.", "In one of the simplest configurations, the apparatus incorporates a means for drying the surface of material in at least one drying sieve.", "The apparatus includes a housing, at least one discharge opening, a fan assembly within the housing, and an activation device to control the operation of the fan assembly.", "The top surface of the housing has at least one sieve opening to cooperate with at least one sieve to permit fluid communication between the housing interior space and the surrounding atmosphere.", "The at least one discharge opening is formed in the housing fluidly connecting the interior space of the housing with the surrounding atmosphere.", "The fan assembly is oriented to draw air from the surrounding atmosphere through the mixture in the at least one sieve and the at least one sieve opening and to discharge air through the at least one discharge opening to the surrounding atmosphere.", "Lastly, the activation device controls the operation of the fan assembly.", "[0032] The housing may be of virtually any shape than defines an interior space and may include at least one drain hole formed in the housing bottom surface to permit fluid that may accumulate in the housing to drain from the housing.", "The bottom surface may be formed to pitch toward the at least one drain hole.", "The housing may be constructed of virtually any material, including coated materials.", "The housing may be elevated from an external surface by at least one support device, which may be as simple as fixed legs, or may include more advanced adjustability and rotational features.", "[0033] The at least one discharge opening of the fan assembly may be located on any of the surfaces of the enclosure and may be fitted with various accessories, such as a safety screen, sound attenuator, or exhaust ductwork.", "[0034] In one particular embodiment, the fan assembly consists of a housed fan having a fan housing, a fan wheel, and a motor.", "Alternative embodiments may incorporate a plurality of fans.", "The fan assembly may be mounted in the housing in a number of ways, such as rigidly attached to the housing, or mounted to the housing with a vibration isolation system.", "[0035] The apparatus includes the activation device for controlling the operation of the fan assembly.", "Such activation device may be as simple as a plug style connector to cooperate with a common electrical connector, or may involve more complex controls, such as electronic controls or variable speed drive controls.", "Further embodiments may include a weight measuring system having at least one weight sensor and at least one display device.", "The at least one weight sensor may be formed as a sieve receiver adapted to receive and releasably hold the sieve over the sieve opening, or may include multiple sensors to cooperate with the sieve, or may be part of the at least one support device.", "Having the weight sensor as part of the at least one support device would be particularly useful in the single sieve opening embodiment, as the fan assembly would not have to be turned off during the reading since the at least one weight sensor will be measuring the weight of the entire apparatus rather than just the sieve and its contents.", "[0036] A control module may be adapted to receive data from the weight measuring system and at least one input device.", "The at least one input device may be any number of external devices such as a keyboard, or may include an input device built into the control module.", "The control module may then perform calculations, and display data on one at least one display device.", "The control module may also include memory to retain the input and output data.", "The calculations performed may include bulk specific gravity of the compacted specimen, the theoretical maximum specific gravity, and the air void percentage in the compacted mix, according to the equations seen above.", "Further, the control device may incorporate the function of the activation device in controlling the operation of the fan assembly.", "Additionally, the control module may be adapted to transmit data to at least one printer, either external to the apparatus or integral to the control module.", "[0037] These variations, modifications, alternatives, and alterations of the various preferred embodiments, arrangements, and configurations may be used alone or in combination with one another as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings.", "BRIEF DESCRIPTION OF THE DRAWINGS [0038] Without limiting the scope of the present invention as claimed below and referring now to the drawings and figures: [0039] [0039 ]FIG. 1 shows a prior art setup for drying the surface of aggregate, in side elevation view, not to scale;", "[0040] [0040 ]FIG. 2 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale;", "[0041] [0041 ]FIG. 3 shows the apparatus of FIG. 1 in top plan view, not to scale;", "[0042] [0042 ]FIG. 4 shows the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale;", "[0043] [0043 ]FIG. 5 shows a variation of the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale;", "[0044] [0044 ]FIG. 6 shows a variation of the apparatus of FIG. 1 in cross-sectional view taken along section line 4 - 4 in FIG. 3, not to scale;", "[0045] [0045 ]FIG. 7 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale;", "[0046] [0046 ]FIG. 8 shows an embodiment of the apparatus for drying the surface of aggregate in elevated perspective view, not to scale;", "and [0047] [0047 ]FIG. 9 shows a variation of the apparatus of FIG. 1 in top plan view, not to scale.", "DETAILED DESCRIPTION OF THE INVENTION [0048] The apparatus for drying the surface of aggregate of the instant invention enables a significant advance in the state of the art.", "The preferred embodiments of the apparatus accomplish this by new and novel arrangements of elements and methods that are configured in unique and novel ways and which demonstrate previously unavailable but preferred and desirable capabilities.", "[0049] The detailed description set forth below in connection with the drawings is intended merely as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized.", "The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments.", "It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.", "In its simplest form the apparatus for drying the surface of aggregate in at least one sieve S incorporates a housing 100 , at least one discharge opening 170 , a fan assembly 200 , and an activation device 400 to control the operation of the fan assembly 200 , as seen in FIG. 2. The housing 100 has an interior space defined by at least one top surface 110 , at least one bottom surface 120 , and at least one side surface.", "The at least one top surface 110 is formed to have at least one sieve opening 180 of a size and configuration to cooperate with the at least one sieve S and to permit fluid communication between the housing interior space and the surrounding atmosphere, illustrated best in FIG. 3. The at least one discharge opening 170 is formed in the housing 100 thereby fluidly connecting the interior space of the housing with the surrounding atmosphere.", "The fan assembly 200 is positioned within the housing 100 and oriented to draw air from the surrounding atmosphere through the aggregate, the at least one sieve S, and the at least one sieve opening 180 , seen in FIG. 4, and discharge air through the at least one discharge opening 170 to the surrounding atmosphere.", "Lastly, the activation device 400 controls the operation of the fan assembly 200 .", "[0050] Referring again to FIG. 2, in one particular embodiment, the housing 100 further includes a front surface 130 , a back surface 140 , a left side surface 160 , and a right side surface 150 , thereby defining the interior space.", "In this illustrative embodiment, the at least one sieve opening 180 is approximately twelve inches in diameter to cooperate with the sieve size commonly used in an aggregate testing laboratory, but it may be any shape or size.", "Further, the housing 100 may include any number of sieve openings 180 .", "[0051] A further variation of the apparatus includes at least one drain hole 190 formed in the housing bottom surface 120 to permit fluid communication between the housing interior space and the surrounding atmosphere, as illustrated in FIG. 5 and FIG. 6. Therefore, any moisture that may accumulate in the housing 100 may be permitted to drain from the housing 100 , reducing the health risks associated with stagnant water.", "Further, the bottom surface may be formed to pitch toward the at least one drain hole.", "[0052] The housing 100 may be constructed of virtually any material, including, but not limited to, sheet metal, plastic, wood, and various composites.", "The material of construction may further be coated with any number of commercially available coatings to perform such functions as inhibiting corrosion as well as inhibiting microbial growth, among many others.", "[0053] At least one support device 300 may be attached to the enclosure 100 to elevate the bottom surface 120 from an external surface, as seen in FIG. 5. The at least one support device 300 may be as simple as fixed legs, or may include more advanced adjustability and rotational features.", "[0054] The at least one discharge opening 170 may be located on any of the surfaces of the enclosure.", "Just one configuration, that of top surface discharge, is illustrated in the figures.", "The at least one discharge opening 180 may be outfitted with any number of accessories.", "As one with skill in the art will appreciate, the at least one discharge opening 180 may be outfitted with a safety screen to prevent objects from coming in contact with the fan assembly 200 .", "Further, the at least one discharge opening 170 may be formed with a duct connection point so that the discharge air may be ducted outside, or other discharge location.", "Additionally, the at least one discharge opening 170 may incorporate a sound attenuator to minimize the transmission of noise from the discharge opening.", "The at least one discharge opening 170 size may vary with the airflow of the fan assembly 200 and may be configured in any shape and size.", "[0055] The fan assembly 200 may incorporate air movement devices in virtually any form.", "In one particular embodiment, the fan assembly consists 200 of a housed fan having a fan housing 220 , a fan wheel 210 rotably and releasable housed in the fan housing, and a motor 230 rotably and releasably joined to the fan wheel 210 , as seen in FIG. 4. Such a double inlet centrifugal fan may be either direct drive, or belt drive as seen in FIG. 6. In the belt drive embodiment the motor 230 and the fan wheel 210 are rotably and releasably coupled by at least one belt 240 .", "Alternative embodiments may incorporate a plurality of fans within the housing 100 .", "[0056] The fan assembly 200 may be mounted in the housing 100 in a number of ways.", "For instance, the fan assembly 200 may be rigidly attached to the housing 100 .", "Alternatively, the fan assembly 200 may be mounted to the housing 100 with a vibration isolation system 250 , as seen in FIG. 6. Such vibration isolation system 250 may include an inertia base and a flexible connection at the interface of the fan housing and the at least one discharge opening.", "Further, the fan assembly 200 may be suspended within the housing 100 with suspension type vibration isolators.", "[0057] The apparatus includes the activation device 400 for controlling the operation of the fan assembly 200 .", "Such activation device 400 may be as simple as a plug style connector to cooperate with a common electrical connector, or may involve more complex controls.", "As illustrated in FIG. 2, the activation device 400 may be a switch.", "Alternatively, as will be seen later, the activation device 400 may consists of electronic controls specifying the start and stop of the fan assembly 200 .", "Similarly, the activation device 400 may incorporate more advanced controls such as variable speed drives to control fan activation, deactivation, and speed.", "[0058] Further embodiments may include a weight measuring system 600 having at least one weight sensor 610 and at least one display device 620 , as seen in FIG. 8. The at least one weight sensor 610 may be formed as a sieve receiver adapted to receive and releasably hold the sieve S over the sieve opening 180 , as illustrated on the leftmost opening of FIG. 8. Alternatively, the at least one weight sensor 610 may include multiple sensors to cooperate with the sieve S, as illustrated in the rightmost opening of FIG. 8. The at least one display device 620 receives data from the at least one weight sensor 610 and computes a weight associated with the data to be displayed on the at least one display device 620 .", "The weight measurement system 600 may include electronic memory to store and display many weight readings during the process of drying the surface of the aggregate, as well as timing features.", "The fan system 200 would have to be off while the weight measurement readings were taken so that the negative pressure acting on the interior space, and therefore the sieve S, does not to affect such readings.", "As one with skill in the art will recognize, a timing/sampling circuit may be incorporated into the weight measurement system 600 such that weight measurements may occur at predetermined intervals and such that the fan system 200 is disabled during such readings, when required.", "[0059] In a further embodiment, the at least one support device 300 may incorporate the at least one weight sensor 610 .", "This would be particularly useful in the single sieve opening 180 embodiment illustrated in FIG. 9. In such an embodiment the fan assembly 200 would not have to be turned off during the reading since the at least one weight sensor 610 will be measuring the weight of the entire apparatus rather than just the sieve S and its contents.", "[0060] Yet another embodiment may include a control module 500 adapted to receive data from the weight measuring system 600 and at least one input device 510 .", "The at least one input device 510 may be any number of external devices such as a keyboard, or may include an input device 510 built into the control module 500 such as that shown in FIG. 7. The control module 500 may then perform calculations, and display data on one at least one display device 520 .", "The control module 500 may also include memory to retain the input and output data.", "The calculations performed may include bulk specific gravity of the compacted specimen, the theoretical maximum specific gravity, and the air void percentage in the compacted mix, according to the equations seen above.", "Further, the control device 500 may incorporate the function of the activation device 400 in controlling the operation of the fan assembly 200 .", "Additionally, the control module 500 may be adapted to transmit data to at least one printer 530 , either external to the apparatus or integral to the control module.", "[0061] Numerous alterations, modifications, and variations of the preferred embodiments disclosed herein will be apparent to those skilled in the art and they are all anticipated and contemplated to be within the spirit and scope of the instant invention.", "For example, although specific embodiments have been described in detail, those with skill in the art will understand that the preceding embodiments and variations can be modified to incorporate various types of substitute and or additional or alternative materials, relative arrangement of elements, and dimensional configurations.", "Accordingly, even though only few variations of the present invention are described herein, it is to be understood that the practice of such additional modifications and variations and the equivalents thereof, are within the spirit and scope of the invention as defined in the following claims.", "[0062] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed." ]
[0001] This application claims priority under 35 U.S.C. §119(e) of provisional application Ser. No. 60/961,752, filed on Jul. 24, 2007. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a manufacturing method to control the size velocity and relative position of a reclosable mechanism or multiple reclosable mechanisms, such as a zipper or zippers on a flexible plastic film, bag or pouch. [0004] 2. Description of the Prior Art [0005] In the prior art of the manufacture of zippers and similar devices for reclosable plastic film, bags or pouches, the velocity of the delivery of the resin to the profiles or to the locking elements could not be accurately controlled by such elements as a choke device. This inability to accurately control the resin velocity made it difficult to extrude complex locking mechanisms at a reasonable cost and production rate. [0006] Further prior art includes methods where the zipper tape is extruded, wound and then, in a secondary process, unwound, heated and attached to the film. Still further prior art may be found in published patent application US2005/0269733 A1 entitled “Method of and Apparatus for Forming Multiple Closure Elements”. OBJECTS AND SUMMARY OF THE INVENTION [0007] It is therefore an object of the present invention to provide a method and apparatus for the manufacture of complex locking mechanisms for reclosable interlocking elements, such as a zipper profile on a flexible film plastic package, bag or pouch, at a reasonable cost and production rate. [0008] It is therefore a further object of the present invention to provide accurate control of the velocity of the resin flow delivered to the profile at its point of juncture with the film or tubing of the reclosable plastic package, bag or pouch. [0009] It is therefore a still further object of the present invention to improve adhesion of closure elements to the body of the package, bag or pouch by preventing exposure of the contact surfaces. [0010] These and other objects are attained by cooling the integral profile tubing and drawing it in a negative ratio whereby the circumference of the cooled and drawn finished tubing is less than the circumference of the die plate. The resin for the profile interlocking elements is delivered from a co-extruder through a separate channel, or several separate channels, to the die body and thence to the die plate, where the resin is joined to the film (tubing) at a controlled rate, with the control being the speed of the co-extruder drive. DESCRIPTION OF THE DRAWINGS [0011] Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein: [0012] FIG. 1 is a schematic of the apparatus of the present invention. [0013] FIGS. 2 a - 2 i are examples of zipper profiles which can be produced by the apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0014] Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the several views, one sees that FIG. 1 is a schematic of the apparatus 10 of the present invention. Extrusion die body 12 receives the material for the formation of the tubing (e.g. a tube or a film), such as, but not limited to, low density polyethylene, from primary extruder 14 and extruder material hopper 16 via supply channel 18 . Supply channel 18 joins extrusion die body primary supply channel 20 which is formed within extrusion die body 12 . Extrusion die body primary supply channel 20 , in turns, feeds the material for the tubing to the extrusion die cavity 22 where the tube or film 100 is formed. Tube or film 100 , typically in a cylindrical shape, exits from the mouth 24 of extrusion die plate 13 , and therefore may be referred to as tubing (or as a low density polyethylene bubble). The tubing is typically drawn into a negative ratio and cooled. That is, due to the speed of the film and related factors, the circumference of the cooled and drawn finished tubing 100 is typically less than the circumference of the extrusion die plate 13 , but in some applications may be the same size or even greater than the circumference of the extrusion die plate 13 . [0015] Secondary extruders 30 , 34 include respective secondary extruder material hoppers 32 , 36 supplying material, such as resin (which may be colored or uncolored), for the formation of the reclosable profiles. The use of colored resin allows the user to see and handle the profiles more easily. The resin, or similar material, may be the same in secondary extruders 30 , 34 or may be different (including such characteristics as color). It is envisioned, however, that the primary extruder 14 would supply a flexible, soft and pliable material while the secondary extruders 30 , 34 would supply a more rigid, robust material for forming reclosable profiles 102 , 104 . The resin, or similar material, is provided via respective secondary supply channels 38 , 40 (typically implemented as heated hoses) and respective secondary die body supply channels 42 , 44 to the die plate, where it is joined to the tubing 100 at a controlled rate (as well as a controlled temperature), with the control being the speed of the drive of the secondary extruders 30 , 34 , thereby forming reclosable profiles 102 , 104 on tubing 100 . The resin (or other material) from the secondary extruders 30 , 34 for forming the reclosable profiles 102 , 104 does not come into contact with the material (tube or film 100 ) from the primary extruder 14 until it reaches the extrusion die plate 13 typically approximately one half inch (although other distances are envisioned) before both exit the extrusion die body 12 . The control of the speed of the drive of the secondary extruders 30 , 34 and or control of the temperature of the resin or similar material provided to the secondary supply channels 38 , 40 (is, in turn, typically controlled by CPU 200 or a similar processing device) thereby provides the ability to extrude more complex shapes of the interlocking elements than was previously possible. Additionally, it is envisioned that as many as nine, or even more, secondary extruders may be used, with respective material supplies and secondary supply channels to form the various complex shapes. FIGS. 2 a - 2 i are representative of a sample of the many profile shapes that are possible with various embodiments of the present invention which, applicant believes, have been difficult, if not impossible, to obtain with the prior art, particularly with respect to multiple interlocking elements formed on a single profile. [0016] The resulting configuration typically has many or all of the following advantages: [0017] 1. the velocity and speed of the resin for the locking mechanism is controlled separately from that of the tubing; [0018] 2. the velocity of the resin for the interlocking elements is controlled accurately and separately from that of the tubing; [0019] 3. the distance between sets of profiles is controlled; [0020] 4. more complex locking mechanisms may be manufactured; [0021] 5. the cooling rate of the interlocking elements is accurately controlled; [0022] 6. more complex multiple interlocking elements are possible; [0023] 7. interlocking elements with separators between the interlocking elements can be provided; [0024] 8. the shapes, construction and structural characteristics of the interlocking elements are controlled, including profiles with multiple interlocking elements; [0025] 9. the tubing may have two or more sets of profiles, each set provided with separate sources of profile control; [0026] 10. the separate resin source can be a co-extruder (or secondary extruder); [0027] 11. the profiles are provided with multiple interlocking elements; [0028] 12. a co-extruder (or secondary extruder) can provide resin flows to several sets of profiles or a separate co-extruder (or secondary extruder) can be used for each resin flow; [0029] 13. the flow of resin to the profiles can be controlled, so that the profiles cool at a controlled rate; and [0030] 14. the speed of the profile extrusion can be controlled so that the speed of the profile extrusion and the speed of the film extrusion are equal when the profile and the film come into contact with each other. [0031] Thus the several aforementioned objects and advantages are most effectively attained. Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.
The apparatus includes an extrusion die and further includes a main or primary extruder for the supply of material, such as low density polyethylene, to form the tubing for the manufacture of reclosable packages, bags or pouches. The apparatus further includes at least one secondary extruder, or co-extruder, for the extruding of each reclosable profile onto the tubing. The speed of the co-extruders is controlled so as to control the extrusion of the reclosable profiles.
Briefly summarize the invention's components and working principles as described in the document.
[ "[0001] This application claims priority under 35 U.S.C. §119(e) of provisional application Ser.", "No. 60/961,752, filed on Jul. 24, 2007.", "BACKGROUND OF THE INVENTION [0002] 1.", "Field of the Invention [0003] The present invention relates to a manufacturing method to control the size velocity and relative position of a reclosable mechanism or multiple reclosable mechanisms, such as a zipper or zippers on a flexible plastic film, bag or pouch.", "[0004] 2.", "Description of the Prior Art [0005] In the prior art of the manufacture of zippers and similar devices for reclosable plastic film, bags or pouches, the velocity of the delivery of the resin to the profiles or to the locking elements could not be accurately controlled by such elements as a choke device.", "This inability to accurately control the resin velocity made it difficult to extrude complex locking mechanisms at a reasonable cost and production rate.", "[0006] Further prior art includes methods where the zipper tape is extruded, wound and then, in a secondary process, unwound, heated and attached to the film.", "Still further prior art may be found in published patent application US2005/0269733 A1 entitled “Method of and Apparatus for Forming Multiple Closure Elements.”", "OBJECTS AND SUMMARY OF THE INVENTION [0007] It is therefore an object of the present invention to provide a method and apparatus for the manufacture of complex locking mechanisms for reclosable interlocking elements, such as a zipper profile on a flexible film plastic package, bag or pouch, at a reasonable cost and production rate.", "[0008] It is therefore a further object of the present invention to provide accurate control of the velocity of the resin flow delivered to the profile at its point of juncture with the film or tubing of the reclosable plastic package, bag or pouch.", "[0009] It is therefore a still further object of the present invention to improve adhesion of closure elements to the body of the package, bag or pouch by preventing exposure of the contact surfaces.", "[0010] These and other objects are attained by cooling the integral profile tubing and drawing it in a negative ratio whereby the circumference of the cooled and drawn finished tubing is less than the circumference of the die plate.", "The resin for the profile interlocking elements is delivered from a co-extruder through a separate channel, or several separate channels, to the die body and thence to the die plate, where the resin is joined to the film (tubing) at a controlled rate, with the control being the speed of the co-extruder drive.", "DESCRIPTION OF THE DRAWINGS [0011] Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein: [0012] FIG. 1 is a schematic of the apparatus of the present invention.", "[0013] FIGS. 2 a - 2 i are examples of zipper profiles which can be produced by the apparatus of the present invention.", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0014] Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the several views, one sees that FIG. 1 is a schematic of the apparatus 10 of the present invention.", "Extrusion die body 12 receives the material for the formation of the tubing (e.g. a tube or a film), such as, but not limited to, low density polyethylene, from primary extruder 14 and extruder material hopper 16 via supply channel 18 .", "Supply channel 18 joins extrusion die body primary supply channel 20 which is formed within extrusion die body 12 .", "Extrusion die body primary supply channel 20 , in turns, feeds the material for the tubing to the extrusion die cavity 22 where the tube or film 100 is formed.", "Tube or film 100 , typically in a cylindrical shape, exits from the mouth 24 of extrusion die plate 13 , and therefore may be referred to as tubing (or as a low density polyethylene bubble).", "The tubing is typically drawn into a negative ratio and cooled.", "That is, due to the speed of the film and related factors, the circumference of the cooled and drawn finished tubing 100 is typically less than the circumference of the extrusion die plate 13 , but in some applications may be the same size or even greater than the circumference of the extrusion die plate 13 .", "[0015] Secondary extruders 30 , 34 include respective secondary extruder material hoppers 32 , 36 supplying material, such as resin (which may be colored or uncolored), for the formation of the reclosable profiles.", "The use of colored resin allows the user to see and handle the profiles more easily.", "The resin, or similar material, may be the same in secondary extruders 30 , 34 or may be different (including such characteristics as color).", "It is envisioned, however, that the primary extruder 14 would supply a flexible, soft and pliable material while the secondary extruders 30 , 34 would supply a more rigid, robust material for forming reclosable profiles 102 , 104 .", "The resin, or similar material, is provided via respective secondary supply channels 38 , 40 (typically implemented as heated hoses) and respective secondary die body supply channels 42 , 44 to the die plate, where it is joined to the tubing 100 at a controlled rate (as well as a controlled temperature), with the control being the speed of the drive of the secondary extruders 30 , 34 , thereby forming reclosable profiles 102 , 104 on tubing 100 .", "The resin (or other material) from the secondary extruders 30 , 34 for forming the reclosable profiles 102 , 104 does not come into contact with the material (tube or film 100 ) from the primary extruder 14 until it reaches the extrusion die plate 13 typically approximately one half inch (although other distances are envisioned) before both exit the extrusion die body 12 .", "The control of the speed of the drive of the secondary extruders 30 , 34 and or control of the temperature of the resin or similar material provided to the secondary supply channels 38 , 40 (is, in turn, typically controlled by CPU 200 or a similar processing device) thereby provides the ability to extrude more complex shapes of the interlocking elements than was previously possible.", "Additionally, it is envisioned that as many as nine, or even more, secondary extruders may be used, with respective material supplies and secondary supply channels to form the various complex shapes.", "FIGS. 2 a - 2 i are representative of a sample of the many profile shapes that are possible with various embodiments of the present invention which, applicant believes, have been difficult, if not impossible, to obtain with the prior art, particularly with respect to multiple interlocking elements formed on a single profile.", "[0016] The resulting configuration typically has many or all of the following advantages: [0017] 1.", "the velocity and speed of the resin for the locking mechanism is controlled separately from that of the tubing;", "[0018] 2.", "the velocity of the resin for the interlocking elements is controlled accurately and separately from that of the tubing;", "[0019] 3.", "the distance between sets of profiles is controlled;", "[0020] 4.", "more complex locking mechanisms may be manufactured;", "[0021] 5.", "the cooling rate of the interlocking elements is accurately controlled;", "[0022] 6.", "more complex multiple interlocking elements are possible;", "[0023] 7.", "interlocking elements with separators between the interlocking elements can be provided;", "[0024] 8.", "the shapes, construction and structural characteristics of the interlocking elements are controlled, including profiles with multiple interlocking elements;", "[0025] 9.", "the tubing may have two or more sets of profiles, each set provided with separate sources of profile control;", "[0026] 10.", "the separate resin source can be a co-extruder (or secondary extruder);", "[0027] 11.", "the profiles are provided with multiple interlocking elements;", "[0028] 12.", "a co-extruder (or secondary extruder) can provide resin flows to several sets of profiles or a separate co-extruder (or secondary extruder) can be used for each resin flow;", "[0029] 13.", "the flow of resin to the profiles can be controlled, so that the profiles cool at a controlled rate;", "and [0030] 14.", "the speed of the profile extrusion can be controlled so that the speed of the profile extrusion and the speed of the film extrusion are equal when the profile and the film come into contact with each other.", "[0031] Thus the several aforementioned objects and advantages are most effectively attained.", "Although preferred embodiments of the invention have been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims." ]
FIELD OF THE INVENTION The present invention relates to a printing element comprising at least one polymer layer which has photoimageable constituents and additions to make the polymer layer either more hydrophobic or hydrophilic. The printing element may have two polymer layers on a substrate in which one of the layers comprises fluorinated acrylates or methacrylates. BACKGROUND Verbanic et al (U.S. Pat. No. 3,055,932) discloses unsaturated esters of fluorinated glycols and acyl halides. It discloses preparation of compositions of matter which are useful in the formation of polymeric materials for high temperature applications. The present invention is directed to an article comprising at least one layer of polymer deposited on a substrate wherein the layer contains fluorinated compounds or additives that adjust the relative hydrophobicity of the layers. BRIEF DESCRIPTION OF THE DRAWINGS AND FIGURES FIGS. 1A and 1B illustrate a bi-layer structure for differential inking. FIGS. 2A and 2B illustrate a bi-layer structure for differential inking. FIG. 3 illustrates drop diameters as a function of concentration of fluorinated surfactants in the polymer layer. SUMMARY OF THE INVENTION The invention is directed to an article comprising: a) a substrate b) a first polymer layer disposed on the substrate wherein the first polymer layer comprises: i) an elastomeric polymer; and ii) a initiator; and c) a second polymer layer disposed on the first polymer layer wherein the second polymer layer comprises i) an elastomeric polymer; and ii) a photoinitiator; and wherein the first polymer layer or the second polymer layer further comprises a polymer of monomers selected from the group consisting of: and mixtures thereof; and wherein the polymer layer that does not contain the polymer of the monomers contains a polymer of non-fluorinated acrylate or methacrylate monomers. The invention is further directed to an article comprising: a) a substrate b) a first polymer layer disposed on the substrate wherein the a first polymer layer comprises i) an elastomeric polymer; ii) an initiator; and iii) a polymer selected from non-fluorinated acrylate or methacrylate monomers; c) a second polymer layer disposed on the first polymer layer wherein the a second polymer layer comprises i) an elastomeric polymer; ii) a photoinitiator; and iii) a polymer selected from a non-fluorinated acrylate or methacrylate monomers; wherein the first or the second polymer layer comprises fluorinated additives. The invention is still further directed to a process comprising: a) providing a substrate b) depositing a first polymer layer on the substrate, the first polymer layer comprising i) an elastomeric polymer; ii) an initiator; and iii) non-fluorinated acrylate or methacrylate monomers c) crosslinking the first polymer layer; d) depositing a second polymer layer on the first polymer layer, the second polymer layer comprising; i) an elastomeric polymer; ii) a photoinitiator; and iii) monomers selected from the group consisting of: and mixtures thereof; e) imaging a pattern on the second polymer layer forming an imaged pattern; and f) developing the imaged pattern. The invention is also directed to a process comprising: a) providing a substrate; b) depositing a first polymer layer on the substrate wherein the first polymer layer comprises i) an elastomeric polymer; ii) a initiator; iii) monomers selected from the group consisting of: and mixtures thereof; c) crosslinking the first polymer layer; d) depositing a second polymer layer on the first polymer layer wherein the second polymer layer comprises; i) an elastomeric polymer; ii) a photoinitiator; and iii) monomers selected from non-fluorinated acrylate or methacrylate; e) imaging a pattern on the second polymer layer forming an imaged pattern; and f) developing the imaged pattern. DETAILED DESCRIPTION In a standard imaged and processed flexographic printing plate, the difference in height (Δh) between the uppermost relief features and the floor of the plate typically ranges from about 100-500 microns. This dimension depends upon the desired size of the relief features and other specifics unique to the printing plate. When plates are intended to be used for high resolution printing applications (i.e. printing in the micron range), the value of Δh must be reduced so as to be comparable to the plate's very small feature sizes. Typically, the Δh-to-feature size ratio falls near unity for most high resolution printing processes. Unfortunately, the reduction in Δh tends to compromise the plate's mechanical durability and its elastomeric behavior that is required for good conformal contact between the plate and the object to be printed. One solution to this limitation involves the fabrication of a bi-layer construct that has both a photo- or a thermo-crosslinkable elastomeric floor layer providing for good mechanical properties and a thin photo-imageable elastomeric layer that is sequentially deposited on top that contains the desired relief features arranged in a pattern. In this way, the properties of the two layers can each be optimized separately so that the bottom layer adjacent to the substrate controls the plate's elastic modulus for optimal printing while the thin upper layer (with Δh˜desired feature size) controls the plate's printing resolution. Bi-layer plates that are fabricated in this manner can be designed for differential inking with hydrophilic inks. Here, the printing plate comprises a flexible support or substrate and two additional crosslinkable elastomeric layers of essentially the same composition that have very different surface energies. Both of these additional layers would comprise elastomeric photopolymer compositions and one of these layers would also contain fluorinated nanoparticles, fluorinated additives (e.g. Zonyl® fluorosurfactants, DuPont, Wilmington, Del.), fluorinated telomers or fluorinated acrylate or methacrylate crosslinking monomers. The fluorine containing layer could be chosen to be at the top or at the bottom of the bi-layer printing plate. If the fluorine containing layer is at the top, the bottom layer would selectively ink with hydrophilic inks. On the other hand, if the fluorine modified layer is at the bottom, the top layer would selectively ink when hydrophilic inks are used. In either of these cases, good printing resolution is achieved because the relatively more hydrophobic fluorinated portions of the plate are not wetted by the ink while the other more hydrophilic areas are wetted by the ink. These concepts are illustrated in FIGS. 1 and 2 . FIG. 1A shows a bi-layer printing plate containing fluorinated additives or fluorinated particles ( 16 ) that operates in a Gravure mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer and ( 10 ) is a photo-crosslinked elastomeric layer containing fluorinated additives or particles that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern. FIG. 1B shows a bi-layer printing plate containing fluorinated additives or fluorinated particles ( 16 ) that operates in a flexographic mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer that contains fluorinated additives or particles and ( 10 ) is a photo-crosslinked elastomeric layer that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern. FIG. 2A shows a bi-layer printing plate containing fluorinated monomers that operates in a Gravure mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer and ( 18 ) is a photo-crosslinked elastomeric layer containing fluorinated crosslinking monomers that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern. FIG. 2B shows a bi-layer printing plate containing fluorinated monomers that operates in a flexographic mode with hydrophilic inks where ( 14 ) is a support layer, ( 16 ) is a photo- or a thermally crosslinked elastomeric layer that contains fluorinated crosslinking momoners and ( 10 ) is a photo-crosslinked elastomeric layer that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern. Gravure or flexographic bi-layer printing plates that can be selectively inked with hydrophobic inks can be fabricated in a similar manner. In this case, both layers of the bi-layer plate would also comprise crosslinked elastomeric photopolymer compositions and one of the layers would also contain hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide, or acrylate or methacrylate crosslinking monomers fitted with hydrophilic (e.g. hydroxyl carboxylic acid) functional groups. If the upper layer contained the hydrophilic additives or functional groups, the bottom layer of the bi-layer plate would selectively ink when contacted by hydrophobic inks. Conversely, if the hydrophilic layer is at the bottom, the upper layer of the plate would selectively ink when hydrophobic inks are employed. Again, good printing resolution is achieved because the relatively more hydrophilic portions of the bi-layer plate are not wetted by the hydrophobic ink while the other more hydrophobic areas of the plate are wetted by the ink. Depending upon the particular application desired, the target resolution for high resolution printing plates can be in the range of 1-15 microns. Printing electronic devices using a reel-to-reel process requires the ability to print high resolution lines and spaces. The source-drain level of a thin film transistor is particularly demanding because the channel lengths required for good transistor performances are on the order of only a few microns. Currently it is not possible to print at these micron resolutions using available materials and/or processes. Standard printing plates do not have nearly the required resolution. In contrast, molded polydimethylsiloxane (PDMS) plates can reach these resolutions but are typically limited to printing thiol layers. Bi-layer plates are described which are fabricated from commercially available block copolymers like poly(styrene-butadiene-styrene) or poly(styrene-isoprene-styrene) elastomers that have been mixed with smaller crosslinkable acrylate or methacrylate monomers. These polymerizable mixtures furnish robust, semi-interpenetrating networks (SIPNs) when crosslinked thermally or photochemically. The SIPN layers that result are elastomeric in their mechanical behaviors and form the two working layers contained in the bi-layer plate where one of the layers also contains hydrophobic or hydrophilic additives and/or monomers to modify its surface energy relative to the other layer. The two SIPN layers formed in this manner are chemically resistant to many solvents and dispersants that are used in standard ink formulations, including ethanol, aqueous alcohol mixtures, toluene and ortho-dichlorobenzene. Moreover, because the two SIPN layers contain many of these same chemical components, inter-layer adhesion between the two adjacent layers can be maintained. In addition to poly(styrene-butadiene-styrene) or poly(styrene-isoprene-styrene) elastomers, other elastomeric polymers and rubbers can also be used to form the two polymeric SIPN layers in the bi-layer plate, including various copolymers of butadiene with acrylonitrile and neoprene rubbers. One embodiment of the present invention is an article which may be used as a printing element. In this embodiment, the substrate is selected to be relatively hydrophilic. The substrate may be Mylar® (DuPont Teijin Films, Bristol, UK). A relatively hydrophobic polymer layer is deposited on the substrate. The polymer layer may be deposited by spin coating, bar coating, spraying, dipping or similar coating technologies known to one skilled in the art. The polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents. Appropriate photoimaging constituents may include photoinitiators and/or photosensitizers among others. The polymer layer also comprises a polymer of the monomers selected from the group consisting of: and mixtures thereof. The polymer layer may optionally further comprise fluorinated additives such as Zonyl® fluorosurfactants (DuPont, Wilmington Del.) or fluorinated particles. In this embodiment, the substrate is relatively hydrophilic while the polymer layer is hydrophobic due to the incorporation of the fluorinated monomers and/or fluorinated additives. A second embodiment of the present invention is an article which may be used as a printing element. In this embodiment, the substrate is selected to be relatively hydrophobic. The substrate may be plasma treated polytetrafluoroethylene or another plasma treated fluoropolymer. A polymer layer is deposited on the substrate. The polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents. Appropriate photoimaging constituents may include photoinitiators and/or photosensitizers among others. The polymer layer may optionally comprise hydrophilic additives such as ionic surfactants or hydrophilic particles of silica, alumina or titanium dioxide. The polymer layer further comprises a polymer of non-fluorinated (meth)acrylate monomers that contain hydrophilic substituents such as hydroxyl or carboxylic acid groups. In this embodiment, the substrate is hydrophobic while the polymer layer relatively hydrophilic. A third embodiment of the present invention is an article which may be used as a printing element. In this embodiment, the substrate may be any material that may be coated. A first polymer layer is deposited on the substrate. The first polymer layer may be deposited by any known coating technique. The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator. The initiator may be Irgacure® 907 ( 2 -Methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone) (Ciba Specialty Chemicals, Basel, Switzerland). A second polymer layer is deposited onto the first polymer layer. The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents. Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others. Either the first polymer layer or the second polymer layer, but not both, also comprises a polymer of the monomers selected from the group consisting of: and mixtures thereof. The polymer layer which comprises the polymer formed from the monomers above may optionally further comprise fluorinated additives such as Zonyl® fluorosurfactants (DuPont, Wilmington Del.) or fluorinated particles. The polymer layer that does not contain the polymer of the monomers contains a polymer of non-fluorinated acrylate or methacrylate crosslinking monomers. A fourth embodiment of the present invention is an article which may be used as a printing element. In this embodiment, the substrate may be any material which may be coated. A first polymer layer is deposited on the substrate. The first polymer layer may be deposited by any known coating technique. The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator. The initiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). A second polymer layer is deposited onto the first polymer layer. The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents. Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others. Both the first and the second polymer layer also comprise a polymer of non-fluorinated acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be trimethylolpropane triacrylate (TMPTA), ethoxylated trimethylolpropane triacrylate (TMPEOTA) and/or 1,12-dodecanediol dimethacrylate (Sartomer CD262). Furthermore, either the first polymer layer or the second polymer layer, but not both, also comprises fluorinated particles or fluorinated additives that include Zonyl® fluorosurfactants (DuPont, Wilmington Del.). A fifth embodiment of the present invention is an article which may be used as a printing element. In this embodiment, the substrate may be any material which may be coated. A first polymer layer is deposited on the substrate. The first polymer layer may be deposited by any known coating technique. The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator. The initiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). A second polymer layer is deposited onto the first polymer layer. The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents. Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others. Both the first polymer layer and the second polymer layer also comprise a polymer of non-fluorinated acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. Furthermore, either the first polymer layer or the second polymer layer, but not both, also comprises hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide. The present invention is also a process to make printing elements. In one embodiment, a substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a first layer on the substrate. The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-fluorinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The first layer may be deposited by any known coating technique. The initiator may be di(4-tert-butylcyclohexyl) peroxydicarbonate, Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The next step in the process is crosslinking the first layer. The crosslinking step may be thermal or, if the initiator is a photoinitiator, the crosslinking step may be by flood irradiation. In the next step of the process, a second layer is deposited onto the first polymer layer. The second layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and fluorinated monomers selected from the group consisting of: and mixtures thereof. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The subsequent step in the process is irradiating an image into the second layer. The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image. In a second process embodiment, a substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a first layer on the substrate. The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and fluorinated monomers selected from the group consisting of: and mixtures thereof. The first layer may be deposited by any known coating technique. The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The next step in the process is crosslinking the first layer. The crosslinking step may be thermal or, if the initiator is a photoinitiator, the crosslinking step may be by flood irradiation. In the next step of the process, a second layer is deposited onto the first polymer layer. The second layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-fluorinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The subsequent step in the process is irradiating an image into the second layer. The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image. In a third process embodiment of the present invention, a substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a first layer on the substrate. The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-flourinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The deposition of the first layer may be by any known coating technique The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The next step in the process is crosslinking the first polymer layer. The crosslinking may be thermal or, if the initiator is a photoinitiator, the crosslinking may be by flood irradiation. In the next step of the process, a second layer is deposited onto the first polymer layer. The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-flourinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland. The subsequent step in the process is irradiating an image into the second polymer layer. The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions of the exposed image. Either the first polymer layer or the second polymer layer, but not both, further comprises fluorinated particles or fluorinated additives that may include Zonyl® fluorosurfactants (DuPont, Wilmington Del.). In a fourth process embodiment of the present invention, a substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a first layer on the substrate. The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-flourinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The deposition of the first layer may be by any known coating technique The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland) The next step in the process is crosslinking the first polymer layer. The crosslinking may be thermal or, if the initiator is a photoinitiator, the crosslinking may be by flood irradiation. In the next step of the process, a second layer is deposited onto the first polymer layer. The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-flourinated crosslinking acrylate or methacrylate monomers. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland. The subsequent step in the process is irradiating an image into the second polymer layer. The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions of the exposed image. Either the first polymer layer or the second polymer layer, but not both, further comprises hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide. In a fifth process embodiment of the present invention, a relatively hydrophilic substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a layer on the substrate. The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and fluorinated monomers selected from the group consisting of: and mixtures thereof. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The subsequent step in the process is irradiating an image into the layer. The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image. In a sixth process embodiment of the present invention, a relatively hydrophilic substrate is provided. The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK). The next step in the process is depositing a layer on the substrate. The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator, non-fluorinated acrylate or methacrylate crosslinking monomers and fluorinated particles or fluorinated surfactants such as Zonyl fluorosurfactants (DuPont, Wilmington Del.). The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The subsequent step in the process is irradiating an image into the layer. The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image. In another process embodiment of the present invention, a relatively hydrophobic substrate is provided. The substrate may be plasma treated polytetrafluoroethylene or another plasma treated fluoropolymer. The next step in the process is depositing a layer on the substrate. The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator, non-fluorinated acrylate or methacrylate crosslinking monomers and hydrophilic surfactants or hydrophilic additives that may include silica, alumina or titanium dioxide particles. The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262. The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland). The subsequent step in the process is irradiating an image into the layer. The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image. EXAMPLES Examples 1-9 These examples illustrate the effect of fluorine containing additives on the hydrophilicity of the surface of a thermal sub-layer composition. The non-fluorinated thermally crosslinkable polymer composition with the amount listed below in Table 1 was mixed and stirred at ambient temperature for a minimum of four hours or until the solid components were fully dissolved. 7.2 grams (1 gram solids) of the mixture were weight into 10 ml vials for the addition of the fluorine containing additive. One of three Zonyl fluorosurfactant additives, Z225, FTS or FSN, (DuPont) was added to each vial at the concentration specified in Table 1 and stirred overnight. A thin film of each of the compositions was coated onto a clean 2″×2″ silicon wafer. The wafer was cleaned as follows; an acetone rinse was followed by a methanol and a DI-water rinse. The wafer was dried with high pressure nitrogen and exposed to an oxygen plasma treatment for 5 minutes in plasma-preen unit prior to coating of the film. The film was spin-coated at 3000 RPM for 90 seconds and then dried in a nitrogen purge box for 5 minutes prior to UV exposure. The films were flood exposed using an i-liner OAI (345 nm) for 10 minutes. The various crosslinked films that resulted were tested for their Ag ink wetting. A 5 micro liter drop of DGP50 silver ink (Advanced NanoProducts, Soeul, Korea) was dispensed from a height of 1″ above the surface of the film onto each of the surfaces of the various compositions. The drop was allowed to dry and the radius of the dry drop was then measured. The drop radius (in mm) as a function of fluorinated additive concentration is shown in Table 2 and FIG. 3 for the cases where fluorinated additives were not added to the compositions, the ink drop were observed to spread easily on the hydrophilic photopolymer surfaces. As the amount of fluorinated additive was increased, the film surfaces became progressively more hydrophobic and the radii of the drops became considerably smaller. As shown in Table 2 and FIG. 3 , both the FTS and the Z225 fluorosurfactant additives were found to be particularly effective in rendering the polymer film surfaces more hydrophobic (diminished ink drop radii). TABLE 1 Weight % grs Kraton DKX 73.5 7.35 TMPEOTA 19.5 2.4 Perkodox 16 5 0.5 GMA 2 0.5 Kraton DKX, styrene butadiene styrene TMPEOTA Perkodox thermal initiator, GMA glycidyl methacrylate TABLE 2 Drop radius (mm) % Fluorination Ex: 1-3 FTS Ex 4-6 Z225 Ex 6-9 FSN 0.0100 23.00 22.00 24.00 0.1000 15.00 12.00 20.00 1.0000 6.000 5.000 17.00 Example 10-11 The following examples illustrate the ability to selectively ink only the desired areas of a bi-layer plate operating in a Gravure mode (top layer does not ink while the bottom layer inks). The ability to differentially ink was achieved as follows. Two photopolymer compositions with similar formulations, but one containing the fluorosurfactant additive Zonyl Z225 (Example 11) and the other devoid of the additive (Example 10), were prepared. The two compositions are defined in Table 3 below. TABLE 3 Ex-10 Top Layer Bottom Layer (control) Ex 11 Top Layer Vector 4111A 3.875 grs (77.5%) 4.075 grs (81.5%) 4.075 grs (81.5%) CD501 0.875 grs (17.5%) 0.875 grs (17.5%)  0.85 grs (17.0%) Irgacure 907 0.025 grs (0.5%) 0.025 grs (0.5%) ITX  0.01 grs (0.2%)  0.01 grs (0.2%) TAOBN 0.015 grs(0.3%% 0.015 grs(0.3%% Perkodox 16  0.25 grs (5%) Zonyl Z225  0.05 grs (1%) Where, Vector 4111A (Dexco Polymers LP, Houston, TX) is an styrene-isoprene-styrene block copolymer employed as a binder Sartomer CD501 is a diacrylate monomer (Sartomer Co, Exton, PA) Irgacure 907 is a photo-initiator ITX is a photo-sensitizer (Ciba Specialty Chemicals, Basel, Switzerland) TAOBN is an oxygen inhibitor (Stratford Research, Inc., Stratford, CT) Zonyl Z225 is a fluorinated surfactant The bi-layer plates of Example 10 and Example 11 were fabricated onto clean 4″ Si wafers. The wafers were first cleaned by an acetone rinse, followed by sequential methanol and DI-water rinses. The wafers were dried using a high pressure nitrogen gun. The wafers were then placed in an oxygen plasma using a Plasma Preen unit for 5 minutes. Bottom layers with compositions defined in column 2 of Table 3 were spin-coated at 3000 RPM for 90 seconds for both samples (Example 10 and Example 11). After completing the coating steps, the wafers were purged for 5 minutes in a nitrogen atmosphere and then flood-exposed for 10 minutes using an OAI 345 nm i-liner also under a nitrogen atmosphere. A second layer was then applied to each. For the control sample (Example 10) the composition of the top layer is defined in column 3 of Table 3. The composition of the top layer for Example 11 is defined by column 4 in Table 3 where 1% of the fluorosurfactant Zonyl Z225 has also been added. The top layers were spin-coated onto the crosslinked bottom layers at 3000 RPM for 90 seconds. The samples were allowed to dry in a nitrogen atmosphere for 2 minutes prior to exposure with an i-liner OAI at 345 nm. Exposures were made through a photomask for 5 minutes prior to the development of the upper layers to remove material from the non-exposed areas. A soda lime glass-chrome patterned photomask was used to make ten 1 cm×2.5 cm test patterns. Each individual test pattern was ½ positive (clear features) and ½ negative (clear background). Within each negative and positive area were a series of rectangles and lines. 3 and 5 micron rectangles were alternated and were sized with 1:1, 1:3 and 1:5 aspect ratios. The lines were 0.25″ in long and varied in width and spacing from 3 to 100 um. A neutral density filter with ten 1 cm×2.5 cm optical densities was aligned over the test patterns on the photomask. Thus a single exposure time would produce an exposure series. For example, a five minute exposure through an optical density of 0.01 corresponds to a 3 second exposure. This process allowed us to rapidly determine correct exposure time for each formulation as well as exposure latitude. After exposure was completed the sample was developed in Cylosol® for 2 minutes and dried by blowing it with a nitrogen gun. The resolution of the resulting plates was analyzed via optical microcospy prior to inking. Both the control plate (Example 10) and fluorosurfactant containing plate (Example 11) were inked with a Ag nanoink DGP40 diluted 1:5 in alcohol. The ink was spin-coated onto the plate at 3000 RPM. The inked plates were then observed with an optical microscope and the areas that were inked and non-inked were determined both for the control and the fluorinated plates. Microscopic analyses showed that while the control plate was coated by ink throughout the plate, the plate with the fluorine-containing top layer inked only in those regions were the top fluorinated layer was absent, thus exposing the relatively more hydrophilic bottom layer to the ink. Since the recess areas of this plate ink while its upper relief layer containing the fluorosurfactant additive does not ink, this bi-layer plate operates in a Gravure mode. Moreover, the recess lines ranging from 3 to 30 micrometers in size were inked while the relief lines that separated the recess lines were not inked. Inking of the image was very uniform and silver containing lines showed good electrical continuity as measured by a two-point probe. The large areas with rectangular relief and recess features were also inked. While the control (example 10) showed no inking differentiation, only the recessed regions of the plate were inked in Example 11. Example 12-13 The following example illustrates the ability to selectively ink a bi-layer plate comprising a hydrophilic latex underlay and a fluorinated positive resist overlay. Two photopolymer compositions of essentially the same formulation but one with a fluorinated additive and the other without the additive were prepared. The compositions are shown in Table 4 below. TABLE 4 Ex-12 Top Layer A Ex 13 Top Bottom Layer A (control) Layer B Vector 4111A  3.75 grs (75%)  3.75 grs (75%)  3.75 grs (75%) CD501 1.175 grs (23.5%) 1.175 grs (23.5%) 1.175 grs (23.5%) Irgacure 907  0.05 grs (1.0%)  0.05 grs (1.0%)  0.05 grs (1.0%) ITX  0.01 grs (0.2%)  0.01 grs (0.2%)  0.01 grs (0.2%) TAOBN 0.015 grs(0.3%% 0.015 grs(0.3%% 0.015 grs(0.3%% Zonyl FTS  0.05 grs (1%) Where, Vector 4111A an SIS block co-polymer is used as a binder CD501 di-acrylate monomer Irgacure 907 is a photo-initiator ITX is a sensitizer TAOBN is an oxygen inhibitor Zonyl FTS is a fluorinated surfactant The bi-layer plates were fabricated onto a clean 4″ Si wafer. The wafer was first clean with an acetone rinse, followed by sequential methanol and DI-water rinses. The wafer was then dried using high pressure nitrogen gun. The wafer was then placed in an oxygen plasma using a plasma preen unit for 5 minutes. The bottom layer with composition A was spun coated at 3000 RPM for 90 seconds for both samples; example 10 and example 11. After coating the wafers were purged for 5 minutes in a nitrogen atmosphere and flood exposed for 10 minutes using a OAI 345 nm i-liner also in a Nitrogen atmosphere. A second layer was then applied. On the control sample the composition of the top layer was identical to that in the bottom layer (columns 2 and 3 Table 3). On sample B the composition of composition of the top layer is that of column 4 in Table 3 above which only varies by the addition of 0.5% FTS relative to that of the bottom layer. The top layers were spun onto the crosslinked bottom layers at 3000 RPM for 90 seconds. The samples were let dry in a nitrogen atmosphere for 2 minutes prior to their exposure in an i-liner at 345 nm and exposed through a photomask for 5 minutes prior to its development. The pattern in the photomasks (Chrome on glass) comprised 10 repeats of a basic pattern 1″ in height and 0.5″ in width; ½ positive (clear features) and ½ negative (clear background. This basic repeat unit comprised 3 and 5 micron patches as well as an assortment of lines and spaces. The features in the 5 microns patch all 5 microns in height vary in length from 5 to 50 microns. The features in the 3 micron patch all 3 microns in height vary in length from 3 to 30 microns. The line, 0.25″ in length ranged from 3 to 100 microns in width; with spaces also varying in that range. This basic pattern area was repeated 10 times on the photomask. By placing a neutral density filter on top with areas of constant density that match the area of the underlying basic pattern, 10 different exposures could be obtained from a single exposure. That is, an optical density corresponds to a specific light transmission; thus an reduction in overall exposure time. For example, a 5 minute exposure through an neutral density filter with an OD of 0.01 corresponds to a 3 second exposure. Therefore by exposing through a 10 step filter we were able to rapidly determine the correct exposure for each formulation as well as the exposure latitude. After exposure was completed the sample was developed in Cylosol® for 2 minutes and dried by blowing it with a nitrogen gun. The resolution of the plates was analyzed via optical microcospy prior to inking. Both the control and sample plates were ink with a Ag nanoink (ANP) DGP40 1:5 in alcohol. The ink was spun onto the plate at 3000 RPM. The inked plates were then observed in an optical microscope and areas that ink and did not ink determined both for the control and fluorinated plates. Results show that while the control plate inks throughout the plate, the sample with the fluorinated top layer inks only in those regions were the fluorinated layer was not exposed and was removed by the solvent, then exposing the hydrophilic bottom layer. Since these sample inks in the recess areas of the plate and not in the relief areas of the plate, these examples illustrate selective inking in a gravure mode. The optical micrograph images illustrate that while recess and relief features ink in example 12 only the acrylic latex inks in example 13. The micrograph shows that the 10 microns recess lines inked while surrounding relief lines essentially did not. The image illustrates selective inking of various recess features 5 micron wide. Example 14-17 The following example illustrates the ability to selectively ink a single layer fluorinated plate coated on a hydrophilic substrate. The ability to differentially ink was achieved as follows. The photopolymer compositions comprise various monomers whose preparations are listed in Table 5 below. TABLE 5 Example 14 Ex-15 Ex-16 Ex-17 20% Kraton DKX 19.75 grs (79%) 19.75 grs 79% 19.75 grs 19.75 grs in toluene (79%) (79%) Compound 1 0.97 grs (19.4%) Compound 2 0.97 grs 19.4% Compound 3 0.40 (4%) 0.97 grs 19.4% Compound 4 0.97 grs 19.4% Irgacure 907 0.5 0.001 grs (1%) GMA 0.05 grs (1%) 0.05 grs (1%) 0.05 grs 0.05 grs (1%) (1%) DPL 0.025 grs (0.5%) 0.025 grs (0.5%) 0.025 grs 0.025 grs (0.5%) (0.5%) TAOBN 0.0375 grs (0.075%) 0.0375 grs 0.0375 gr 0.0375 gr (0.075%) (0.075%) 0.075% Differential inking 4 2 4 2 observed 1-5 (5 is highest) Printing resolution 5 5 20 5 obtained (microns) Where, Kraton DKX222CS SBS block co-polymer is used as a binder Compound 1 is a fluorinated linear dimethacrylate with a F/C ratio = 0.82 Compound 2 is a fluorinated branched dimethacrylate with a F/C ratio = 0.76 Compound 3 is a fluorinated linear dimethacrylate with a F/C ratio = 1.0 Compound 4 is a fluorinated linear dimethacrylate with a F/C ratio = 0.75 Irgacure 907 is a photo-initiator DPL is lauryl 5-(N,N-diethylamino)-2-phenylsulfonyl-2,4-pentadienoate TAOBN is an oxygen inhibitor The chemical structures and preparation of the four fluorinated dimethacrylates (compounds 1-4) with differing fluorine-to-carbon (F/C) ratios are described below. Preparation of the Above Di-Methacrylate, Compound 1 A solution of 1H,1H,9H,9H-perfluoro-1,9-nonanediol (19.1 g, 46.3 mmol) and methacrylic anhydride (57.1 g, 370 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm). The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature. The tetrahydrofuran solvent was carefully removed under reduced pressure. The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent. The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 91% yield. Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals at 1742 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond). Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group). Theoretical flourine-to-carbon ratio=0.82 Preparation of the Above Di-Methacrylate, Compound 2 A solution of 1H,2H,3H,3H-perfluorononane-1,2-diol (19.5 g, 49.5 mmol) and methacrylic anhydride (76.0 g, 493 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.100 g) and 4-methoxyphenol (100 ppm). The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature. The tetrahydrofuran solvent was carefully removed under reduced pressure. The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent. The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 76% yield. Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals near 1750 cm-1 (ester carbonyl) and 1637 cm-1 (methacrylate double bond). Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group). Theoretical fluorine-to-carbon ratio=0.76. Preparation of the Above Di-Methacrylate, Compound 3 A solution of 1H,1H,12H,12H-perfluoro-1,12-dodecanediol (25.3 g, 45.0 mmol) and methacrylic anhydride (57.1 g, 370 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm). The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature. The tetrahydrofuran solvent was carefully removed under reduced pressure. The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent. The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 89% yield. Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals at 1743 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond). Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group). Theoretical flourine-to-carbon ratio=1.0. Preparation of the Above Di-Methacrylate, Compound 4 A solution of 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecane-1,11-diol (24.0 g, 58.5 mmol) and methacrylic anhydride (45.0 g, 292 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm). The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature. The tetrahydrofuran solvent was carefully removed under reduced pressure. The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent. The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL). The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 86% yield. Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals near 1742 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond). Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group). Theoretical fluorine-to-carbon ratio=0.75. The printing plates in Examples 14-17 were fabricated on the acrylic side of a clean ST504 Melinex base (DuPont Teijin Films, Bristol, UK), which is highly hydrophillic. The base was first clean with a methanol rinse, followed by sequential DI water and isopropyl alcohol rinses. After a final rinse in DI water, the base was dried using high pressure nitrogen gun. The formulations were mixed overnight at room temperature and filtered through 1.5 um GMF filters. Each layer was spun onto the acrylic side of ST504 (DuPont Teijin Films, Bristol, UK) at 1000 RPM for 90 seconds and then exposed through a photomask for 10 minutes prior to its development in an OAI i-liner at 345 nm The pattern in the photomasks (Chrome on glass) comprised 10 repeats of a basic pattern 1″ in height and 0.5″ in width; ½ positive (clear features) and ½ negative (clear background. This basic repeat unit comprised 3 and 5 micron patches as well as an assortment of lines and spaces. The features in the 5 microns patch all 5 microns in height vary in length from 5 to 50 microns. The features in the 3 micron patch all 3 microns in height vary in length from 3 to 30 microns. The line and spaces, 0.25″ in length ranged from 3 to 100 microns in width. This basic pattern area was repeated 10 times on the photomask. By placing a neutral density filter on top with areas of constant density that match the area of the underlying basic pattern, 10 different exposures could be obtained in a single experiment. That is, an optical density corresponds to a specific light transmission; thus a reduction in overall exposure time. For example, a 5 minute exposure through a neutral density filter with an OD of 0.01 corresponds to a 3 second exposure. Therefore by exposing through a 10 step filter we were able to rapidly determine the correct exposure for each formulation as well as the exposure latitude. After exposure was completed the sample was developed in toluene for 2 minutes and dried by blowing it with a nitrogen gun. The resolution of the plates (below, top right) was analyzed via optical microcopy prior to inking. The sample plates were inked with a Ag nanoink DGP40 1:5 in alcohol. Where was the ink purchased from Advanced NanoProducts, Soeul, Korea. The ink was spun onto the plate at 3000 RPM. The inked plates were then observed in an optical microscope and areas that ink and did not ink determined. The plates have 3-5 micron resolution and selective inking can be achieved in the flexo mode. In compound 3, the high degree of fluorination led to modeling of the film surface with the lowering of the feature resolution. Compound 1 led to excellent resolution and selectivity of inking. As the fluorination was decreased, the selectivity decreased as well. Although small feature sizes were maintained the ink selectivity was not fully achieved. Example 18-22 The following example illustrates the contact angle of the ink on plate formulations comprising various fluorinated monomers. The compositions and contact angles in water, toluene and ethanol are listed in Table 7 below. The compositions in table 7, were stirred overnight at room temperature and coated on Si wafers. The wafer was first clean with an acetone rinse, followed by sequential methanol and DI-water rinses. The wafer was then dried using high pressure nitrogen gun. The wafer was then placed in an oxygen plasma using a Plasma Preen unit for 5 minutes. The films with the compositions of table 7 were spun coated at 1000 RPM for 90 seconds for both samples. The samples were let dry in a nitrogen atmosphere for 2 minutes prior to their flood exposure in an i-liner at 345 nm for 5 minutes development. The contact angles with water, toluene and ethanol were measured with a VCA2500xe instrument manufactured by ASTProducts (Advanced Surface Technologies) in Billerica, Mass. TABLE 7 Control Ex. 18 Ex-19  Ex-20 Ex-21  Ex-22 20% Kraton 88% 70% 70% 70% 70% DKX222 in toluene   22 grs 17.5 grs 17.5 grs 17.5 grs 17.5 grs Irgacure 907  1%  1%  1%  1%  1% 0.05 grs 0.05 grs 0.05 grs 0.05 grs 0.05 grs ITX  1%  1%  1%  1%  1% 0.05 grs 0.05 grs 0.05 grs 0.05 grs 0.05 grs GMA 10% 10% 10% 10% 10%  0.5 grs  0.5 grs  0.5 grs  0.5 grs  0.5 grs PFS 18%  0.9 grs PFOA 18%  0.9 grs PFHDA 18%  0.9 grs VE-OPPVE 18%  0.9 grs Adv. Contact 98 101 103 89 108 angle in H2O Adv, Contact 18 54 21 18 56 angle in toluene Adv. Contact wets 33 wets wets 25 angle in EtOH Where, Kraton DKX222CS is an SBS block is used as a binder Irgacure 907 is a photo-initiator GMA is glycidyl methacrylate PFS is perfluorostyrene PFOA is perfluorooctyl acrylate PFHDA is perfluorohexyl di-acrylate VE-OPPVE is 1,1,1,2,2,3,3-heptafluoro-3-(1,1,1,2,3,3-hexafluoro-3-(2-vinyloxy)ethoxy)propan-2-yloxy)propane TX is a sensitizer. In addition, the formulation of example 21 was also imaged through a photomask showing well defined lines, spaces and 3×3 μm, 3×9 μm and 3×15 μm features. Scanning electron micrograph images showed the inking of the recess areas and not inking of the relief areas throughout the plate both for the rectangular features as well as for the 5 to 50 micron lines and spaces. The 3 micron height rectangles with length varying from 3 to 30 microns were inked throughout the 5 mm×5 mm pattern uniformly without any ink retention in the surrounding areas.
The present invention relates a printing element comprising at least one polymer layer which has photoimageable constituents and additions to make the polymer layer either hydrophobic or hydrophilic. The printing element may have two polymer layers on a substrate in which one of the layers comprises fluorinated acrylates or methacrylates.
Summarize the key points of the given document.
[ "FIELD OF THE INVENTION The present invention relates to a printing element comprising at least one polymer layer which has photoimageable constituents and additions to make the polymer layer either more hydrophobic or hydrophilic.", "The printing element may have two polymer layers on a substrate in which one of the layers comprises fluorinated acrylates or methacrylates.", "BACKGROUND Verbanic et al (U.S. Pat. No. 3,055,932) discloses unsaturated esters of fluorinated glycols and acyl halides.", "It discloses preparation of compositions of matter which are useful in the formation of polymeric materials for high temperature applications.", "The present invention is directed to an article comprising at least one layer of polymer deposited on a substrate wherein the layer contains fluorinated compounds or additives that adjust the relative hydrophobicity of the layers.", "BRIEF DESCRIPTION OF THE DRAWINGS AND FIGURES FIGS. 1A and 1B illustrate a bi-layer structure for differential inking.", "FIGS. 2A and 2B illustrate a bi-layer structure for differential inking.", "FIG. 3 illustrates drop diameters as a function of concentration of fluorinated surfactants in the polymer layer.", "SUMMARY OF THE INVENTION The invention is directed to an article comprising: a) a substrate b) a first polymer layer disposed on the substrate wherein the first polymer layer comprises: i) an elastomeric polymer;", "and ii) a initiator;", "and c) a second polymer layer disposed on the first polymer layer wherein the second polymer layer comprises i) an elastomeric polymer;", "and ii) a photoinitiator;", "and wherein the first polymer layer or the second polymer layer further comprises a polymer of monomers selected from the group consisting of: and mixtures thereof;", "and wherein the polymer layer that does not contain the polymer of the monomers contains a polymer of non-fluorinated acrylate or methacrylate monomers.", "The invention is further directed to an article comprising: a) a substrate b) a first polymer layer disposed on the substrate wherein the a first polymer layer comprises i) an elastomeric polymer;", "ii) an initiator;", "and iii) a polymer selected from non-fluorinated acrylate or methacrylate monomers;", "c) a second polymer layer disposed on the first polymer layer wherein the a second polymer layer comprises i) an elastomeric polymer;", "ii) a photoinitiator;", "and iii) a polymer selected from a non-fluorinated acrylate or methacrylate monomers;", "wherein the first or the second polymer layer comprises fluorinated additives.", "The invention is still further directed to a process comprising: a) providing a substrate b) depositing a first polymer layer on the substrate, the first polymer layer comprising i) an elastomeric polymer;", "ii) an initiator;", "and iii) non-fluorinated acrylate or methacrylate monomers c) crosslinking the first polymer layer;", "d) depositing a second polymer layer on the first polymer layer, the second polymer layer comprising;", "i) an elastomeric polymer;", "ii) a photoinitiator;", "and iii) monomers selected from the group consisting of: and mixtures thereof;", "e) imaging a pattern on the second polymer layer forming an imaged pattern;", "and f) developing the imaged pattern.", "The invention is also directed to a process comprising: a) providing a substrate;", "b) depositing a first polymer layer on the substrate wherein the first polymer layer comprises i) an elastomeric polymer;", "ii) a initiator;", "iii) monomers selected from the group consisting of: and mixtures thereof;", "c) crosslinking the first polymer layer;", "d) depositing a second polymer layer on the first polymer layer wherein the second polymer layer comprises;", "i) an elastomeric polymer;", "ii) a photoinitiator;", "and iii) monomers selected from non-fluorinated acrylate or methacrylate;", "e) imaging a pattern on the second polymer layer forming an imaged pattern;", "and f) developing the imaged pattern.", "DETAILED DESCRIPTION In a standard imaged and processed flexographic printing plate, the difference in height (Δh) between the uppermost relief features and the floor of the plate typically ranges from about 100-500 microns.", "This dimension depends upon the desired size of the relief features and other specifics unique to the printing plate.", "When plates are intended to be used for high resolution printing applications (i.e. printing in the micron range), the value of Δh must be reduced so as to be comparable to the plate's very small feature sizes.", "Typically, the Δh-to-feature size ratio falls near unity for most high resolution printing processes.", "Unfortunately, the reduction in Δh tends to compromise the plate's mechanical durability and its elastomeric behavior that is required for good conformal contact between the plate and the object to be printed.", "One solution to this limitation involves the fabrication of a bi-layer construct that has both a photo- or a thermo-crosslinkable elastomeric floor layer providing for good mechanical properties and a thin photo-imageable elastomeric layer that is sequentially deposited on top that contains the desired relief features arranged in a pattern.", "In this way, the properties of the two layers can each be optimized separately so that the bottom layer adjacent to the substrate controls the plate's elastic modulus for optimal printing while the thin upper layer (with Δh˜desired feature size) controls the plate's printing resolution.", "Bi-layer plates that are fabricated in this manner can be designed for differential inking with hydrophilic inks.", "Here, the printing plate comprises a flexible support or substrate and two additional crosslinkable elastomeric layers of essentially the same composition that have very different surface energies.", "Both of these additional layers would comprise elastomeric photopolymer compositions and one of these layers would also contain fluorinated nanoparticles, fluorinated additives (e.g. Zonyl® fluorosurfactants, DuPont, Wilmington, Del.), fluorinated telomers or fluorinated acrylate or methacrylate crosslinking monomers.", "The fluorine containing layer could be chosen to be at the top or at the bottom of the bi-layer printing plate.", "If the fluorine containing layer is at the top, the bottom layer would selectively ink with hydrophilic inks.", "On the other hand, if the fluorine modified layer is at the bottom, the top layer would selectively ink when hydrophilic inks are used.", "In either of these cases, good printing resolution is achieved because the relatively more hydrophobic fluorinated portions of the plate are not wetted by the ink while the other more hydrophilic areas are wetted by the ink.", "These concepts are illustrated in FIGS. 1 and 2 .", "FIG. 1A shows a bi-layer printing plate containing fluorinated additives or fluorinated particles ( 16 ) that operates in a Gravure mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer and ( 10 ) is a photo-crosslinked elastomeric layer containing fluorinated additives or particles that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern.", "FIG. 1B shows a bi-layer printing plate containing fluorinated additives or fluorinated particles ( 16 ) that operates in a flexographic mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer that contains fluorinated additives or particles and ( 10 ) is a photo-crosslinked elastomeric layer that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern.", "FIG. 2A shows a bi-layer printing plate containing fluorinated monomers that operates in a Gravure mode with hydrophilic inks where ( 14 ) is a support layer, ( 12 ) is a photo- or a thermally crosslinked elastomeric layer and ( 18 ) is a photo-crosslinked elastomeric layer containing fluorinated crosslinking monomers that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern.", "FIG. 2B shows a bi-layer printing plate containing fluorinated monomers that operates in a flexographic mode with hydrophilic inks where ( 14 ) is a support layer, ( 16 ) is a photo- or a thermally crosslinked elastomeric layer that contains fluorinated crosslinking momoners and ( 10 ) is a photo-crosslinked elastomeric layer that was exposed to actinic radiation through a photo-mask (imaged) and then subsequently developed to remove non-crosslinked material to form a pattern.", "Gravure or flexographic bi-layer printing plates that can be selectively inked with hydrophobic inks can be fabricated in a similar manner.", "In this case, both layers of the bi-layer plate would also comprise crosslinked elastomeric photopolymer compositions and one of the layers would also contain hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide, or acrylate or methacrylate crosslinking monomers fitted with hydrophilic (e.g. hydroxyl carboxylic acid) functional groups.", "If the upper layer contained the hydrophilic additives or functional groups, the bottom layer of the bi-layer plate would selectively ink when contacted by hydrophobic inks.", "Conversely, if the hydrophilic layer is at the bottom, the upper layer of the plate would selectively ink when hydrophobic inks are employed.", "Again, good printing resolution is achieved because the relatively more hydrophilic portions of the bi-layer plate are not wetted by the hydrophobic ink while the other more hydrophobic areas of the plate are wetted by the ink.", "Depending upon the particular application desired, the target resolution for high resolution printing plates can be in the range of 1-15 microns.", "Printing electronic devices using a reel-to-reel process requires the ability to print high resolution lines and spaces.", "The source-drain level of a thin film transistor is particularly demanding because the channel lengths required for good transistor performances are on the order of only a few microns.", "Currently it is not possible to print at these micron resolutions using available materials and/or processes.", "Standard printing plates do not have nearly the required resolution.", "In contrast, molded polydimethylsiloxane (PDMS) plates can reach these resolutions but are typically limited to printing thiol layers.", "Bi-layer plates are described which are fabricated from commercially available block copolymers like poly(styrene-butadiene-styrene) or poly(styrene-isoprene-styrene) elastomers that have been mixed with smaller crosslinkable acrylate or methacrylate monomers.", "These polymerizable mixtures furnish robust, semi-interpenetrating networks (SIPNs) when crosslinked thermally or photochemically.", "The SIPN layers that result are elastomeric in their mechanical behaviors and form the two working layers contained in the bi-layer plate where one of the layers also contains hydrophobic or hydrophilic additives and/or monomers to modify its surface energy relative to the other layer.", "The two SIPN layers formed in this manner are chemically resistant to many solvents and dispersants that are used in standard ink formulations, including ethanol, aqueous alcohol mixtures, toluene and ortho-dichlorobenzene.", "Moreover, because the two SIPN layers contain many of these same chemical components, inter-layer adhesion between the two adjacent layers can be maintained.", "In addition to poly(styrene-butadiene-styrene) or poly(styrene-isoprene-styrene) elastomers, other elastomeric polymers and rubbers can also be used to form the two polymeric SIPN layers in the bi-layer plate, including various copolymers of butadiene with acrylonitrile and neoprene rubbers.", "One embodiment of the present invention is an article which may be used as a printing element.", "In this embodiment, the substrate is selected to be relatively hydrophilic.", "The substrate may be Mylar® (DuPont Teijin Films, Bristol, UK).", "A relatively hydrophobic polymer layer is deposited on the substrate.", "The polymer layer may be deposited by spin coating, bar coating, spraying, dipping or similar coating technologies known to one skilled in the art.", "The polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents.", "Appropriate photoimaging constituents may include photoinitiators and/or photosensitizers among others.", "The polymer layer also comprises a polymer of the monomers selected from the group consisting of: and mixtures thereof.", "The polymer layer may optionally further comprise fluorinated additives such as Zonyl® fluorosurfactants (DuPont, Wilmington Del.) or fluorinated particles.", "In this embodiment, the substrate is relatively hydrophilic while the polymer layer is hydrophobic due to the incorporation of the fluorinated monomers and/or fluorinated additives.", "A second embodiment of the present invention is an article which may be used as a printing element.", "In this embodiment, the substrate is selected to be relatively hydrophobic.", "The substrate may be plasma treated polytetrafluoroethylene or another plasma treated fluoropolymer.", "A polymer layer is deposited on the substrate.", "The polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents.", "Appropriate photoimaging constituents may include photoinitiators and/or photosensitizers among others.", "The polymer layer may optionally comprise hydrophilic additives such as ionic surfactants or hydrophilic particles of silica, alumina or titanium dioxide.", "The polymer layer further comprises a polymer of non-fluorinated (meth)acrylate monomers that contain hydrophilic substituents such as hydroxyl or carboxylic acid groups.", "In this embodiment, the substrate is hydrophobic while the polymer layer relatively hydrophilic.", "A third embodiment of the present invention is an article which may be used as a printing element.", "In this embodiment, the substrate may be any material that may be coated.", "A first polymer layer is deposited on the substrate.", "The first polymer layer may be deposited by any known coating technique.", "The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator.", "The initiator may be Irgacure® 907 ( 2 -Methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone) (Ciba Specialty Chemicals, Basel, Switzerland).", "A second polymer layer is deposited onto the first polymer layer.", "The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents.", "Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others.", "Either the first polymer layer or the second polymer layer, but not both, also comprises a polymer of the monomers selected from the group consisting of: and mixtures thereof.", "The polymer layer which comprises the polymer formed from the monomers above may optionally further comprise fluorinated additives such as Zonyl® fluorosurfactants (DuPont, Wilmington Del.) or fluorinated particles.", "The polymer layer that does not contain the polymer of the monomers contains a polymer of non-fluorinated acrylate or methacrylate crosslinking monomers.", "A fourth embodiment of the present invention is an article which may be used as a printing element.", "In this embodiment, the substrate may be any material which may be coated.", "A first polymer layer is deposited on the substrate.", "The first polymer layer may be deposited by any known coating technique.", "The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator.", "The initiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "A second polymer layer is deposited onto the first polymer layer.", "The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents.", "Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others.", "Both the first and the second polymer layer also comprise a polymer of non-fluorinated acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be trimethylolpropane triacrylate (TMPTA), ethoxylated trimethylolpropane triacrylate (TMPEOTA) and/or 1,12-dodecanediol dimethacrylate (Sartomer CD262).", "Furthermore, either the first polymer layer or the second polymer layer, but not both, also comprises fluorinated particles or fluorinated additives that include Zonyl® fluorosurfactants (DuPont, Wilmington Del.).", "A fifth embodiment of the present invention is an article which may be used as a printing element.", "In this embodiment, the substrate may be any material which may be coated.", "A first polymer layer is deposited on the substrate.", "The first polymer layer may be deposited by any known coating technique.", "The first polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and initiator.", "The initiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "A second polymer layer is deposited onto the first polymer layer.", "The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene and photoimaging constituents.", "Appropriate photoimaging constituents may include photoinitiators and/or photosensitizors among others.", "Both the first polymer layer and the second polymer layer also comprise a polymer of non-fluorinated acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "Furthermore, either the first polymer layer or the second polymer layer, but not both, also comprises hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide.", "The present invention is also a process to make printing elements.", "In one embodiment, a substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a first layer on the substrate.", "The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-fluorinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The first layer may be deposited by any known coating technique.", "The initiator may be di(4-tert-butylcyclohexyl) peroxydicarbonate, Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The next step in the process is crosslinking the first layer.", "The crosslinking step may be thermal or, if the initiator is a photoinitiator, the crosslinking step may be by flood irradiation.", "In the next step of the process, a second layer is deposited onto the first polymer layer.", "The second layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and fluorinated monomers selected from the group consisting of: and mixtures thereof.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The subsequent step in the process is irradiating an image into the second layer.", "The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image.", "In a second process embodiment, a substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a first layer on the substrate.", "The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and fluorinated monomers selected from the group consisting of: and mixtures thereof.", "The first layer may be deposited by any known coating technique.", "The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The next step in the process is crosslinking the first layer.", "The crosslinking step may be thermal or, if the initiator is a photoinitiator, the crosslinking step may be by flood irradiation.", "In the next step of the process, a second layer is deposited onto the first polymer layer.", "The second layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-fluorinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The subsequent step in the process is irradiating an image into the second layer.", "The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image.", "In a third process embodiment of the present invention, a substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a first layer on the substrate.", "The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-flourinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The deposition of the first layer may be by any known coating technique The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The next step in the process is crosslinking the first polymer layer.", "The crosslinking may be thermal or, if the initiator is a photoinitiator, the crosslinking may be by flood irradiation.", "In the next step of the process, a second layer is deposited onto the first polymer layer.", "The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-flourinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland.", "The subsequent step in the process is irradiating an image into the second polymer layer.", "The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions of the exposed image.", "Either the first polymer layer or the second polymer layer, but not both, further comprises fluorinated particles or fluorinated additives that may include Zonyl® fluorosurfactants (DuPont, Wilmington Del.).", "In a fourth process embodiment of the present invention, a substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a first layer on the substrate.", "The first layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, an initiator and non-flourinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The deposition of the first layer may be by any known coating technique The initiator may be Perkadox® 16 (Akzo Nobel) or Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland) The next step in the process is crosslinking the first polymer layer.", "The crosslinking may be thermal or, if the initiator is a photoinitiator, the crosslinking may be by flood irradiation.", "In the next step of the process, a second layer is deposited onto the first polymer layer.", "The second polymer layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and non-flourinated crosslinking acrylate or methacrylate monomers.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland.", "The subsequent step in the process is irradiating an image into the second polymer layer.", "The next step is developing the irradiated image by exposing the second polymer layer to a developing solution which dissolves the non-irradiated portions of the exposed image.", "Either the first polymer layer or the second polymer layer, but not both, further comprises hydrophilic additives like ionic surfactants or particles of silica, alumina or titanium dioxide.", "In a fifth process embodiment of the present invention, a relatively hydrophilic substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a layer on the substrate.", "The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator and fluorinated monomers selected from the group consisting of: and mixtures thereof.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The subsequent step in the process is irradiating an image into the layer.", "The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image.", "In a sixth process embodiment of the present invention, a relatively hydrophilic substrate is provided.", "The substrate may be Melinex® ST504 (DuPont Teijin Films, Bristol, UK).", "The next step in the process is depositing a layer on the substrate.", "The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator, non-fluorinated acrylate or methacrylate crosslinking monomers and fluorinated particles or fluorinated surfactants such as Zonyl fluorosurfactants (DuPont, Wilmington Del.).", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The subsequent step in the process is irradiating an image into the layer.", "The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image.", "In another process embodiment of the present invention, a relatively hydrophobic substrate is provided.", "The substrate may be plasma treated polytetrafluoroethylene or another plasma treated fluoropolymer.", "The next step in the process is depositing a layer on the substrate.", "The layer comprises a block copolymer of styrene-butadiene-styrene or styrene-isoprene-styrene, a photoinitiator, non-fluorinated acrylate or methacrylate crosslinking monomers and hydrophilic surfactants or hydrophilic additives that may include silica, alumina or titanium dioxide particles.", "The non-fluorinated (meth)acrylate monomers may be TMPTA, TMPEOTA and/or Sartomer CD262.", "The photoinitiator may be Irgacure® 907 (Ciba Specialty Chemicals, Basel, Switzerland).", "The subsequent step in the process is irradiating an image into the layer.", "The next step is developing the irradiated image by exposing the polymer layer to a developing solution which dissolves the non-irradiated portions from the exposed image.", "EXAMPLES Examples 1-9 These examples illustrate the effect of fluorine containing additives on the hydrophilicity of the surface of a thermal sub-layer composition.", "The non-fluorinated thermally crosslinkable polymer composition with the amount listed below in Table 1 was mixed and stirred at ambient temperature for a minimum of four hours or until the solid components were fully dissolved.", "7.2 grams (1 gram solids) of the mixture were weight into 10 ml vials for the addition of the fluorine containing additive.", "One of three Zonyl fluorosurfactant additives, Z225, FTS or FSN, (DuPont) was added to each vial at the concentration specified in Table 1 and stirred overnight.", "A thin film of each of the compositions was coated onto a clean 2″×2″ silicon wafer.", "The wafer was cleaned as follows;", "an acetone rinse was followed by a methanol and a DI-water rinse.", "The wafer was dried with high pressure nitrogen and exposed to an oxygen plasma treatment for 5 minutes in plasma-preen unit prior to coating of the film.", "The film was spin-coated at 3000 RPM for 90 seconds and then dried in a nitrogen purge box for 5 minutes prior to UV exposure.", "The films were flood exposed using an i-liner OAI (345 nm) for 10 minutes.", "The various crosslinked films that resulted were tested for their Ag ink wetting.", "A 5 micro liter drop of DGP50 silver ink (Advanced NanoProducts, Soeul, Korea) was dispensed from a height of 1″ above the surface of the film onto each of the surfaces of the various compositions.", "The drop was allowed to dry and the radius of the dry drop was then measured.", "The drop radius (in mm) as a function of fluorinated additive concentration is shown in Table 2 and FIG. 3 for the cases where fluorinated additives were not added to the compositions, the ink drop were observed to spread easily on the hydrophilic photopolymer surfaces.", "As the amount of fluorinated additive was increased, the film surfaces became progressively more hydrophobic and the radii of the drops became considerably smaller.", "As shown in Table 2 and FIG. 3 , both the FTS and the Z225 fluorosurfactant additives were found to be particularly effective in rendering the polymer film surfaces more hydrophobic (diminished ink drop radii).", "TABLE 1 Weight % grs Kraton DKX 73.5 7.35 TMPEOTA 19.5 2.4 Perkodox 16 5 0.5 GMA 2 0.5 Kraton DKX, styrene butadiene styrene TMPEOTA Perkodox thermal initiator, GMA glycidyl methacrylate TABLE 2 Drop radius (mm) % Fluorination Ex: 1-3 FTS Ex 4-6 Z225 Ex 6-9 FSN 0.0100 23.00 22.00 24.00 0.1000 15.00 12.00 20.00 1.0000 6.000 5.000 17.00 Example 10-11 The following examples illustrate the ability to selectively ink only the desired areas of a bi-layer plate operating in a Gravure mode (top layer does not ink while the bottom layer inks).", "The ability to differentially ink was achieved as follows.", "Two photopolymer compositions with similar formulations, but one containing the fluorosurfactant additive Zonyl Z225 (Example 11) and the other devoid of the additive (Example 10), were prepared.", "The two compositions are defined in Table 3 below.", "TABLE 3 Ex-10 Top Layer Bottom Layer (control) Ex 11 Top Layer Vector 4111A 3.875 grs (77.5%) 4.075 grs (81.5%) 4.075 grs (81.5%) CD501 0.875 grs (17.5%) 0.875 grs (17.5%) 0.85 grs (17.0%) Irgacure 907 0.025 grs (0.5%) 0.025 grs (0.5%) ITX 0.01 grs (0.2%) 0.01 grs (0.2%) TAOBN 0.015 grs(0.3%% 0.015 grs(0.3%% Perkodox 16 0.25 grs (5%) Zonyl Z225 0.05 grs (1%) Where, Vector 4111A (Dexco Polymers LP, Houston, TX) is an styrene-isoprene-styrene block copolymer employed as a binder Sartomer CD501 is a diacrylate monomer (Sartomer Co, Exton, PA) Irgacure 907 is a photo-initiator ITX is a photo-sensitizer (Ciba Specialty Chemicals, Basel, Switzerland) TAOBN is an oxygen inhibitor (Stratford Research, Inc., Stratford, CT) Zonyl Z225 is a fluorinated surfactant The bi-layer plates of Example 10 and Example 11 were fabricated onto clean 4″ Si wafers.", "The wafers were first cleaned by an acetone rinse, followed by sequential methanol and DI-water rinses.", "The wafers were dried using a high pressure nitrogen gun.", "The wafers were then placed in an oxygen plasma using a Plasma Preen unit for 5 minutes.", "Bottom layers with compositions defined in column 2 of Table 3 were spin-coated at 3000 RPM for 90 seconds for both samples (Example 10 and Example 11).", "After completing the coating steps, the wafers were purged for 5 minutes in a nitrogen atmosphere and then flood-exposed for 10 minutes using an OAI 345 nm i-liner also under a nitrogen atmosphere.", "A second layer was then applied to each.", "For the control sample (Example 10) the composition of the top layer is defined in column 3 of Table 3.", "The composition of the top layer for Example 11 is defined by column 4 in Table 3 where 1% of the fluorosurfactant Zonyl Z225 has also been added.", "The top layers were spin-coated onto the crosslinked bottom layers at 3000 RPM for 90 seconds.", "The samples were allowed to dry in a nitrogen atmosphere for 2 minutes prior to exposure with an i-liner OAI at 345 nm.", "Exposures were made through a photomask for 5 minutes prior to the development of the upper layers to remove material from the non-exposed areas.", "A soda lime glass-chrome patterned photomask was used to make ten 1 cm×2.5 cm test patterns.", "Each individual test pattern was ½ positive (clear features) and ½ negative (clear background).", "Within each negative and positive area were a series of rectangles and lines.", "3 and 5 micron rectangles were alternated and were sized with 1:1, 1:3 and 1:5 aspect ratios.", "The lines were 0.25″ in long and varied in width and spacing from 3 to 100 um.", "A neutral density filter with ten 1 cm×2.5 cm optical densities was aligned over the test patterns on the photomask.", "Thus a single exposure time would produce an exposure series.", "For example, a five minute exposure through an optical density of 0.01 corresponds to a 3 second exposure.", "This process allowed us to rapidly determine correct exposure time for each formulation as well as exposure latitude.", "After exposure was completed the sample was developed in Cylosol® for 2 minutes and dried by blowing it with a nitrogen gun.", "The resolution of the resulting plates was analyzed via optical microcospy prior to inking.", "Both the control plate (Example 10) and fluorosurfactant containing plate (Example 11) were inked with a Ag nanoink DGP40 diluted 1:5 in alcohol.", "The ink was spin-coated onto the plate at 3000 RPM.", "The inked plates were then observed with an optical microscope and the areas that were inked and non-inked were determined both for the control and the fluorinated plates.", "Microscopic analyses showed that while the control plate was coated by ink throughout the plate, the plate with the fluorine-containing top layer inked only in those regions were the top fluorinated layer was absent, thus exposing the relatively more hydrophilic bottom layer to the ink.", "Since the recess areas of this plate ink while its upper relief layer containing the fluorosurfactant additive does not ink, this bi-layer plate operates in a Gravure mode.", "Moreover, the recess lines ranging from 3 to 30 micrometers in size were inked while the relief lines that separated the recess lines were not inked.", "Inking of the image was very uniform and silver containing lines showed good electrical continuity as measured by a two-point probe.", "The large areas with rectangular relief and recess features were also inked.", "While the control (example 10) showed no inking differentiation, only the recessed regions of the plate were inked in Example 11.", "Example 12-13 The following example illustrates the ability to selectively ink a bi-layer plate comprising a hydrophilic latex underlay and a fluorinated positive resist overlay.", "Two photopolymer compositions of essentially the same formulation but one with a fluorinated additive and the other without the additive were prepared.", "The compositions are shown in Table 4 below.", "TABLE 4 Ex-12 Top Layer A Ex 13 Top Bottom Layer A (control) Layer B Vector 4111A 3.75 grs (75%) 3.75 grs (75%) 3.75 grs (75%) CD501 1.175 grs (23.5%) 1.175 grs (23.5%) 1.175 grs (23.5%) Irgacure 907 0.05 grs (1.0%) 0.05 grs (1.0%) 0.05 grs (1.0%) ITX 0.01 grs (0.2%) 0.01 grs (0.2%) 0.01 grs (0.2%) TAOBN 0.015 grs(0.3%% 0.015 grs(0.3%% 0.015 grs(0.3%% Zonyl FTS 0.05 grs (1%) Where, Vector 4111A an SIS block co-polymer is used as a binder CD501 di-acrylate monomer Irgacure 907 is a photo-initiator ITX is a sensitizer TAOBN is an oxygen inhibitor Zonyl FTS is a fluorinated surfactant The bi-layer plates were fabricated onto a clean 4″ Si wafer.", "The wafer was first clean with an acetone rinse, followed by sequential methanol and DI-water rinses.", "The wafer was then dried using high pressure nitrogen gun.", "The wafer was then placed in an oxygen plasma using a plasma preen unit for 5 minutes.", "The bottom layer with composition A was spun coated at 3000 RPM for 90 seconds for both samples;", "example 10 and example 11.", "After coating the wafers were purged for 5 minutes in a nitrogen atmosphere and flood exposed for 10 minutes using a OAI 345 nm i-liner also in a Nitrogen atmosphere.", "A second layer was then applied.", "On the control sample the composition of the top layer was identical to that in the bottom layer (columns 2 and 3 Table 3).", "On sample B the composition of composition of the top layer is that of column 4 in Table 3 above which only varies by the addition of 0.5% FTS relative to that of the bottom layer.", "The top layers were spun onto the crosslinked bottom layers at 3000 RPM for 90 seconds.", "The samples were let dry in a nitrogen atmosphere for 2 minutes prior to their exposure in an i-liner at 345 nm and exposed through a photomask for 5 minutes prior to its development.", "The pattern in the photomasks (Chrome on glass) comprised 10 repeats of a basic pattern 1″ in height and 0.5″ in width;", "½ positive (clear features) and ½ negative (clear background.", "This basic repeat unit comprised 3 and 5 micron patches as well as an assortment of lines and spaces.", "The features in the 5 microns patch all 5 microns in height vary in length from 5 to 50 microns.", "The features in the 3 micron patch all 3 microns in height vary in length from 3 to 30 microns.", "The line, 0.25″ in length ranged from 3 to 100 microns in width;", "with spaces also varying in that range.", "This basic pattern area was repeated 10 times on the photomask.", "By placing a neutral density filter on top with areas of constant density that match the area of the underlying basic pattern, 10 different exposures could be obtained from a single exposure.", "That is, an optical density corresponds to a specific light transmission;", "thus an reduction in overall exposure time.", "For example, a 5 minute exposure through an neutral density filter with an OD of 0.01 corresponds to a 3 second exposure.", "Therefore by exposing through a 10 step filter we were able to rapidly determine the correct exposure for each formulation as well as the exposure latitude.", "After exposure was completed the sample was developed in Cylosol® for 2 minutes and dried by blowing it with a nitrogen gun.", "The resolution of the plates was analyzed via optical microcospy prior to inking.", "Both the control and sample plates were ink with a Ag nanoink (ANP) DGP40 1:5 in alcohol.", "The ink was spun onto the plate at 3000 RPM.", "The inked plates were then observed in an optical microscope and areas that ink and did not ink determined both for the control and fluorinated plates.", "Results show that while the control plate inks throughout the plate, the sample with the fluorinated top layer inks only in those regions were the fluorinated layer was not exposed and was removed by the solvent, then exposing the hydrophilic bottom layer.", "Since these sample inks in the recess areas of the plate and not in the relief areas of the plate, these examples illustrate selective inking in a gravure mode.", "The optical micrograph images illustrate that while recess and relief features ink in example 12 only the acrylic latex inks in example 13.", "The micrograph shows that the 10 microns recess lines inked while surrounding relief lines essentially did not.", "The image illustrates selective inking of various recess features 5 micron wide.", "Example 14-17 The following example illustrates the ability to selectively ink a single layer fluorinated plate coated on a hydrophilic substrate.", "The ability to differentially ink was achieved as follows.", "The photopolymer compositions comprise various monomers whose preparations are listed in Table 5 below.", "TABLE 5 Example 14 Ex-15 Ex-16 Ex-17 20% Kraton DKX 19.75 grs (79%) 19.75 grs 79% 19.75 grs 19.75 grs in toluene (79%) (79%) Compound 1 0.97 grs (19.4%) Compound 2 0.97 grs 19.4% Compound 3 0.40 (4%) 0.97 grs 19.4% Compound 4 0.97 grs 19.4% Irgacure 907 0.5 0.001 grs (1%) GMA 0.05 grs (1%) 0.05 grs (1%) 0.05 grs 0.05 grs (1%) (1%) DPL 0.025 grs (0.5%) 0.025 grs (0.5%) 0.025 grs 0.025 grs (0.5%) (0.5%) TAOBN 0.0375 grs (0.075%) 0.0375 grs 0.0375 gr 0.0375 gr (0.075%) (0.075%) 0.075% Differential inking 4 2 4 2 observed 1-5 (5 is highest) Printing resolution 5 5 20 5 obtained (microns) Where, Kraton DKX222CS SBS block co-polymer is used as a binder Compound 1 is a fluorinated linear dimethacrylate with a F/C ratio = 0.82 Compound 2 is a fluorinated branched dimethacrylate with a F/C ratio = 0.76 Compound 3 is a fluorinated linear dimethacrylate with a F/C ratio = 1.0 Compound 4 is a fluorinated linear dimethacrylate with a F/C ratio = 0.75 Irgacure 907 is a photo-initiator DPL is lauryl 5-(N,N-diethylamino)-2-phenylsulfonyl-2,4-pentadienoate TAOBN is an oxygen inhibitor The chemical structures and preparation of the four fluorinated dimethacrylates (compounds 1-4) with differing fluorine-to-carbon (F/C) ratios are described below.", "Preparation of the Above Di-Methacrylate, Compound 1 A solution of 1H,1H,9H,9H-perfluoro-1,9-nonanediol (19.1 g, 46.3 mmol) and methacrylic anhydride (57.1 g, 370 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm).", "The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature.", "The tetrahydrofuran solvent was carefully removed under reduced pressure.", "The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent.", "The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL).", "The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 91% yield.", "Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals at 1742 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond).", "Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group).", "Theoretical flourine-to-carbon ratio=0.82 Preparation of the Above Di-Methacrylate, Compound 2 A solution of 1H,2H,3H,3H-perfluorononane-1,2-diol (19.5 g, 49.5 mmol) and methacrylic anhydride (76.0 g, 493 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.100 g) and 4-methoxyphenol (100 ppm).", "The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature.", "The tetrahydrofuran solvent was carefully removed under reduced pressure.", "The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent.", "The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL).", "The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 76% yield.", "Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals near 1750 cm-1 (ester carbonyl) and 1637 cm-1 (methacrylate double bond).", "Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group).", "Theoretical fluorine-to-carbon ratio=0.76.", "Preparation of the Above Di-Methacrylate, Compound 3 A solution of 1H,1H,12H,12H-perfluoro-1,12-dodecanediol (25.3 g, 45.0 mmol) and methacrylic anhydride (57.1 g, 370 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm).", "The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature.", "The tetrahydrofuran solvent was carefully removed under reduced pressure.", "The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent.", "The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL).", "The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 89% yield.", "Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals at 1743 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond).", "Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group).", "Theoretical flourine-to-carbon ratio=1.0.", "Preparation of the Above Di-Methacrylate, Compound 4 A solution of 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecane-1,11-diol (24.0 g, 58.5 mmol) and methacrylic anhydride (45.0 g, 292 mmol) in tetrahydrofuran (150 mL) was treated with sodium acetate (0.20 g) and 4-methoxyphenol (100 ppm).", "The resulting mixture was heated to reflux under a dried-air atmosphere for 48 hours and then cooled to room temperature.", "The tetrahydrofuran solvent was carefully removed under reduced pressure.", "The concentrated reaction mixture that remained was next diluted with ethyl ether (200 mL) and the resulting solution was rapidly stirred with 2% aqueous sodium carbonate (200 mL) for several hours to hydrolyze excess methacrylic anhydride reagent.", "The organic phase was separated and then sequentially washed with 2% sodium carbonate (100 mL), water (3×100 mL) and brine (50 mL).", "The organic phase was dried over anhydrous sodium sulfate, treated with 4-methoxyphenol (100 ppm) and then concentrated in vacuo to afford a clear, semi-viscous oil in 86% yield.", "Analysis of the product by FTIR revealed the absence of OH stretching near 3400 cm-1 and the presence of new signals near 1742 cm-1 (ester carbonyl) and 1638 cm-1 (methacrylate double bond).", "Proton NMR (CDCl3) spectroscopy confirmed the presence of terminal methacrylate groups in the product with resonances appearing near 6.2 and 5.8 ppm (methacrylate double bond) and 1.9 ppm (methacrylate methyl group).", "Theoretical fluorine-to-carbon ratio=0.75.", "The printing plates in Examples 14-17 were fabricated on the acrylic side of a clean ST504 Melinex base (DuPont Teijin Films, Bristol, UK), which is highly hydrophillic.", "The base was first clean with a methanol rinse, followed by sequential DI water and isopropyl alcohol rinses.", "After a final rinse in DI water, the base was dried using high pressure nitrogen gun.", "The formulations were mixed overnight at room temperature and filtered through 1.5 um GMF filters.", "Each layer was spun onto the acrylic side of ST504 (DuPont Teijin Films, Bristol, UK) at 1000 RPM for 90 seconds and then exposed through a photomask for 10 minutes prior to its development in an OAI i-liner at 345 nm The pattern in the photomasks (Chrome on glass) comprised 10 repeats of a basic pattern 1″ in height and 0.5″ in width;", "½ positive (clear features) and ½ negative (clear background.", "This basic repeat unit comprised 3 and 5 micron patches as well as an assortment of lines and spaces.", "The features in the 5 microns patch all 5 microns in height vary in length from 5 to 50 microns.", "The features in the 3 micron patch all 3 microns in height vary in length from 3 to 30 microns.", "The line and spaces, 0.25″ in length ranged from 3 to 100 microns in width.", "This basic pattern area was repeated 10 times on the photomask.", "By placing a neutral density filter on top with areas of constant density that match the area of the underlying basic pattern, 10 different exposures could be obtained in a single experiment.", "That is, an optical density corresponds to a specific light transmission;", "thus a reduction in overall exposure time.", "For example, a 5 minute exposure through a neutral density filter with an OD of 0.01 corresponds to a 3 second exposure.", "Therefore by exposing through a 10 step filter we were able to rapidly determine the correct exposure for each formulation as well as the exposure latitude.", "After exposure was completed the sample was developed in toluene for 2 minutes and dried by blowing it with a nitrogen gun.", "The resolution of the plates (below, top right) was analyzed via optical microcopy prior to inking.", "The sample plates were inked with a Ag nanoink DGP40 1:5 in alcohol.", "Where was the ink purchased from Advanced NanoProducts, Soeul, Korea.", "The ink was spun onto the plate at 3000 RPM.", "The inked plates were then observed in an optical microscope and areas that ink and did not ink determined.", "The plates have 3-5 micron resolution and selective inking can be achieved in the flexo mode.", "In compound 3, the high degree of fluorination led to modeling of the film surface with the lowering of the feature resolution.", "Compound 1 led to excellent resolution and selectivity of inking.", "As the fluorination was decreased, the selectivity decreased as well.", "Although small feature sizes were maintained the ink selectivity was not fully achieved.", "Example 18-22 The following example illustrates the contact angle of the ink on plate formulations comprising various fluorinated monomers.", "The compositions and contact angles in water, toluene and ethanol are listed in Table 7 below.", "The compositions in table 7, were stirred overnight at room temperature and coated on Si wafers.", "The wafer was first clean with an acetone rinse, followed by sequential methanol and DI-water rinses.", "The wafer was then dried using high pressure nitrogen gun.", "The wafer was then placed in an oxygen plasma using a Plasma Preen unit for 5 minutes.", "The films with the compositions of table 7 were spun coated at 1000 RPM for 90 seconds for both samples.", "The samples were let dry in a nitrogen atmosphere for 2 minutes prior to their flood exposure in an i-liner at 345 nm for 5 minutes development.", "The contact angles with water, toluene and ethanol were measured with a VCA2500xe instrument manufactured by ASTProducts (Advanced Surface Technologies) in Billerica, Mass.", "TABLE 7 Control Ex.", "18 Ex-19 Ex-20 Ex-21 Ex-22 20% Kraton 88% 70% 70% 70% 70% DKX222 in toluene 22 grs 17.5 grs 17.5 grs 17.5 grs 17.5 grs Irgacure 907 1% 1% 1% 1% 1% 0.05 grs 0.05 grs 0.05 grs 0.05 grs 0.05 grs ITX 1% 1% 1% 1% 1% 0.05 grs 0.05 grs 0.05 grs 0.05 grs 0.05 grs GMA 10% 10% 10% 10% 10% 0.5 grs 0.5 grs 0.5 grs 0.5 grs 0.5 grs PFS 18% 0.9 grs PFOA 18% 0.9 grs PFHDA 18% 0.9 grs VE-OPPVE 18% 0.9 grs Adv.", "Contact 98 101 103 89 108 angle in H2O Adv, Contact 18 54 21 18 56 angle in toluene Adv.", "Contact wets 33 wets wets 25 angle in EtOH Where, Kraton DKX222CS is an SBS block is used as a binder Irgacure 907 is a photo-initiator GMA is glycidyl methacrylate PFS is perfluorostyrene PFOA is perfluorooctyl acrylate PFHDA is perfluorohexyl di-acrylate VE-OPPVE is 1,1,1,2,2,3,3-heptafluoro-3-(1,1,1,2,3,3-hexafluoro-3-(2-vinyloxy)ethoxy)propan-2-yloxy)propane TX is a sensitizer.", "In addition, the formulation of example 21 was also imaged through a photomask showing well defined lines, spaces and 3×3 μm, 3×9 μm and 3×15 μm features.", "Scanning electron micrograph images showed the inking of the recess areas and not inking of the relief areas throughout the plate both for the rectangular features as well as for the 5 to 50 micron lines and spaces.", "The 3 micron height rectangles with length varying from 3 to 30 microns were inked throughout the 5 mm×5 mm pattern uniformly without any ink retention in the surrounding areas." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to transfer paper used in a color copying machine, in particular, a color electrophotographic apparatus having a double-side output capability, and to a method of forming color images by using the transfer paper. 2. Description of the Related Art In recent years, an apparatus having full-color output capability and comprising a reader section R for reading a manuscript and a printer section P for outputting images in accordance with manuscript read signals, as shown in FIG. 1, is generally a type of laser printer. An image formation sequence of the apparatus in a case of a full-color mode will be explained briefly. Referring to FIG. 1, when a photosensitive drum 2 is rotated in the direction of an arrow B, a photosensitive member on the photosensitive drum 2 is uniformly charged by a charger 3. Next, image exposure is performed by a laser light E modulated in accordance with a yellow image signal of the color separation signals of a manuscript read by the reader section R, and an electrostatic latent image is thus formed. Next, as a rotor 4a rotates, the latent image is developed by a yellow developer 4Y which is moved to and fixed beforehand at a development position. Next, a transfer member housed within a cassette 101 or 102 is taken out of the cassette by a paper feeding roller 103 or 104, respectively. Further, the transfer member which has been passed through a paper feeding guide 4A, a paper feeding roller 106, and then a paper feeding guide 4B, is held by a gripper 6 at a predetermined timing, and then electrostatically wound around a transfer drum 8 by an abutment roller 7 and an electrode facing the abutment roller 7. The transfer drum 8 is rotated in the direction of an arrow A in synchronization with the photosensitive drum 2. The visual image developed by the yellow developer 4Y is transferred by a transfer charger 9 at a place where the outer peripheral surface of the photosensitive drum 2 abuts the outer peripheral surface of the transfer drum 8. The transfer drum 8 continues to rotate as it is so as to be ready for the transferring of the next color (magenta in FIG. 1). The electric charge of the photosensitive drum 2 is eliminated by a charger 10 for eliminating electric charge. After the photosensitive drum 2 is cleaned by cleaning means 11, it is charged again by a primary charger 3 and undergoes such image exposure as described above in accordance with the next magenta image signal. A rotary developing apparatus then rotates while an electrostatic latent image is formed on the photosensitive drum 2 in accordance with a magenta image signal as a result of the above-mentioned image exposure in order to position a magenta developer 4M at the above-mentioned predetermined development position and perform a predetermined magenta development. Then, the above-described process is performed for cyan and black colors. When the transfer of four colors has been completed, the electric charge of the four-color visual image formed on the transfer member is eliminated by the charger 10 and 13. Then, the transfer member is released by the gripper 6, is separated from the transfer drum 8 by a separation claw 14 and the transfer member is sent to a fixer 16 by a transport belt 15. The transfer member is then fixed by heat and pressure in the nip spacing formed by a fixing roller 161 whose surface is heated by a heating roller 163 and formed by a pressure roller 162, and then the transfer member is ejected onto a tray 17, thus completing a series of full-color print sequences. After the fixing roller 161 has finished fixing the transfer member, the roller is cleaned by a cleaning web 164 so as to be prepared for the next fixing operation. In forming color images using chromatic color toners based on such an electrophotographic method to reproduce a great number of colors, as described above, toners which are coloring powder of yellow, magenta, cyan and black are stacked on the transfer member in multiple layers, and a toner resin is melted by fixing so as to be mixed, that is, color mixing, thereby achieving the above purpose. For this reason, unlike printing using printing ink, a considerable amount of coloring pigment is placed on the paper which is a transfer member, thus causing the external-light shielding power to increase. Under such conditions, as regards a transfer member which can be used in a conventional full-color electrophotographic apparatus as paper formed from chemical pulp, there has been a demand that the transfer member has a proper degree of whiteness which serves as a base for color reproduction, is able to provide a low thermal capacity in which the above-mentioned color mixture by heating is possible, and has a volume resistivity in which electrostatic transferring of at least three times is possible, and having sufficient flexibility to allow the transfer member to be electrostatically wound around the transfer drum. These conditions may be satisfied by using plain paper, which paper generally has a whiteness degree of 85% or more, opaqueness degree of 85% or less, a volume resistivity of 1×10 10 to 10×10 11 Ω·cm (20° C., 65%), a stiffness of 17 to 22 cm (JIS P-8143 A process) though the plain paper has a weight slightly greater than that of ordinary black and white electrophotographic paper. The value of stiffness is measured in the following way. The length from the grasping portion to the leading edge of a test piece when the direction in which the leading edge of the test piece is hung and bent becomes an opposite direction if it is rotated 90° with the grasp line as an axis when one end of the test piece having a long thin, fixed shape is grasped and held upward, is the value of the stiffness. However, in a case in which a full-color image of only one surface is formed using the apparatus shown in FIG. 1 by use of the above-mentioned conventionally used paper, when a full-color image is formed nevertheless on both sides of the paper, there is the possibility that a color tone of the image on a second surface will be considerably affected depending upon the presence or absence of toner on the first surface of the paper when the paper is raised by the hiding power of the toner. Further, since the color of the first surface is made visible in the form of a watermark on a white portion on the second surface even if the first surface is a single image having a uniform density, chroma from a halftone portion to a highlight portion deteriorates considerably. Further, since the toner on the first surface is melted because fixing is performed twice, the toner deeply penetrates the paper, causing offset to increase. SUMMARY OF THE INVENTION It is an object of the present invention to provide transfer paper which is usable for a heating color-mixing type color image forming apparatus employing toner and particularly suitable for forming images on both sides of the paper, such paper being specialized for both-side use which does not produce considerable offset even when heat fixing is performed twice. It is another object of the present invention to provide a method of forming color images in which no offset is produced. The transfer paper for outputting color images in accordance with the present invention has a whiteness degree of 85% or more and a opaqueness degree of 90% or more. The whiteness degree is a value measured by a method prescribed in JIS P8123, which value being represented by a percentage (%) of the reflectance when blue to violet light of the spectrum is irradiated to a sample by using a Hunter whiteness degree tester with respect to the reflectance obtained when the same light is irradiated to a standard magnesium oxide plate. The opaqueness degree is a value measured by a method prescribed in JIS P8123. More specifically, the sample is backed up by a white and black standard plate, respective reflectances are measured via a green filter, the percentage (%) of the former with respect to the latter is represented as an opaqueness degree. A sample of 100% opaqueness degree is completely opaque paper. By using transfer paper having such whiteness or opaqueness degree, a color image having excellent color reproducibility and a small amount of offset can be formed. A transfer member is provided for a color electrophotographic apparatus capable of forming a multi-color toner image by use of at least two colors of single-color toner which comprises a transfer paper for outputting color images having a whiteness degree of 85% or more and an opaqueness degree of 90% or more, said paper containing 65 wt. % of chemical pulp. Objectives and advantages in addition to those discussed above shall be apparent to those skilled in the art from the description of the preferred embodiment of the invention which follows. In the description, reference is made to the accompanying drawings, which form a part hereof, and which illustrate examples of the invention. Such examples, however, are not exhaustive of the various embodiments of the invention, and therefore reference is made to the appended claims for determining the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, longitudinal sectional view of a full-color electrophotographic copying machine in which the transfer paper for outputting color images in accordance with present invention can be used; and FIG. 2 is a graph illustrating the softening characteristics of sharp melt toner. DESCRIPTION OF THE PREFERRED EMBODIMENTS It is preferable that transfer paper in accordance with the present invention be manufactured by adjusting the content of the fine white powder and the weight of the paper. Fine white powder is used to manufacture paper by mixing it with pulp, mixing it with a surface sizing material as surface processing components, or using it as a surface coating material. The content of the fine white powder is preferably 4 g or more per 1 m 2 of the paper. The fine white powder is preferably capable of reflecting light of the entire wavelength in the visible light region. The weight of the paper is preferably 90 g/m 2 or more, and more particularly 100 g/m 2 or more. The degree of whiteness can be made 90% by using fluorescent whitening dye in paper. Since such paper has a small internal scattering factor, the opaqueness is low, approximately 87%. When a patch image is formed by magenta, cyan, and yellow toners of an intensity of 1.6, and red, green and blue toners (made from a combination of two of the above magenta, cyan or yellow toners) on the image on the first side, and observed from the second side, than all six colors can be identified. The smaller the weight of the paper, the smaller the thermal capacity, and therefore color mixing by heating and melting toner can be efficiently performed. When this is done, the weight is preferably not more than 120 g/m 2 . There is an advantage in that this weight can be set at a small value by making opaqueness 90% or more by using fine white powder. The content of the chemical pulp which is a base material for the transfer member in accordance with the present invention is preferably 65 wt. % or more. Paper of 65 wt. % or more is preferable since it prevents the toner itself from being melted too much by the two-time fixing step for both sides of the paper and the paper fibers cannot be penetrated, though it depends upon the heat melting characteristics of the toner used for forming color images. The total amount of the content filler for increasing the degrees of opaqueness and whiteness is preferably 12 wt. % or more and, more preferably 14 wt. % or more. Preferably 4 g/m 2 , or more preferably 6 g/m 2 of fine white powder is contained in this amount. White pigment, such as titanium oxide, magnesium oxide, magnesium sulfate, or calcium carbonate, may preferably be used as the fine white powder. The particle size of the powder contained is preferably from 200 nm to 50 μm in terms of the average volume particle size and, more preferably, not more than 10 μm. The lower limit for the particle size may be that which allows powder in the form of secondary aggregated particles to be present. As primary particles, aggregatable particles, 20 mm or more in size, may be used. Regarding the contained form, classification may be made according to the finished form. Plain paper may be diffused uniformly along the thickness by internally adding paper raw material. When an objective paper in the form of a coated paper is to be obtained, a pulp raw-material and a coated layer may be separately added, or paper to which this powder is added may be used in the final coating. When the transfer paper of the present invention is used to form a color image, sharp melt toner having a low softening point and a low melt viscosity is used because there is a demand for excellent melting properties and color mixing properties when heat is applied. This is because use of such sharp melt toner makes it possible to widen the range in which colors of a copy are reproduced, and to obtain a color copy close to the broad range of colors of the manuscript or a full-color image. Such sharp melt toner is manufactured by melt kneading, grinding, and classifying materials for forming toner, such as a binding resin like polyester resin or styrene-acrylic ester resin, a coloring agent (dye, sublimating dye), or a charge control agent. If necessary, an external addition step for adding various external addition agents (e.g., hydrophobic colloidal silica) to a toner may be performed. For such a color toner, use of a polyester resin as a binding resin is particularly preferred when binding and sharp melt properties are considered. An example of a sharp melt polyester resin is a high polymer compound having ester binding in the principal chain of molecules synthesized from a diol compound and carboxylic acid. In particular, a polyester resin which has bisphenol represented by the following formula: ##STR1## (R is the ethylene or propylene group, x and y are each a positive integer of 1 or more, and the average value of x+y is from 2 to 10), or a polyester resin which has a substituted product thereof as diol components, is preferable because the polyester resin has sharp melting characteristics, in which divalent or higher-valence carboxylic acid, acid anhydride thereof, carboxylic acid components thereof formed of lower alkyl ester (e.g., fumaric acid, maleic acid, maleic acid anhydride, phthalic acid, terephthalic acid, trimellitic acid, or pyromellitic acid) are at least copolycondensed. The softening point of the polyester resin is preferably 75° to 150° C. and, more preferably, 80° to 120° C. An example of the softening characteristics of the sharp melt toner containing this polyester resin as a binding resin is shown in FIG. 2. The measuring conditions are as follows. The CFT-500A type flow tester (manufactured by Shimazu Corp.) was used. The amount of the plunger descent amount/temperature curve (hereinafter referred to as a softening S-shape curve) of the toner was determined, when a die (nozzle) was 0.2 mm in diameter and 1.0 mm in thickness, an extrusion load of 20 kg was applied, at an initial set temperature of 70° C., heated at an even speed of 6° C./minute after a lapse of 300 seconds of warming up. One (1)g to three (3)g of precisely weighed fine powder was used to sample the toner. The cross section of the plunger was set to 1.0 cm 2 . The softening S-shape curve becomes the curve shown in FIG. 2. As it is heated at an even speed, the toner is heated gradually, and begins to flow out (the plunger descends A→B) . Further, when the temperature increases, a substantial amount of molten toner flows out (B→C→D), the plunger stops descending and terminates (D→E). The height H of the S-shape curve indicates the total amount of flowout, and the temperature T0 corresponding to the C point of H/2 indicates the softening point of the toner. Whether the toner and the binding resin have sharp melt properties can be determined by measuring the apparent melt viscosity of the toner and the binding resin. Toners and binding resins having sharp melt properties are ones which satisfy the following conditions, when the temperature at which the apparent melt viscosity shows 10 3 poise is denoted as T1, and the temperature at which the apparent melt viscosity shows 5×10 2 poise is denoted as T2: T1=90° to 150° C. |ΔT|=|T1-T2|=5° to 20° C. The sharp melt resin having these temperature/melt viscosity characteristics has a feature that when it is heated, the viscosity thereof decreases very sharply. Such decrease in viscosity causes the uppermost toner layer to be appropriately mixed with the bottommost toner layer, causes the transparency of the toner layer itself to increase sharply, thereby causing satisfactory color subtraction mixing. EXAMPLE 1 Paper having a thickness of 135 μm and weighing 130 g/m 2 was made by using raw-material pulp containing 16 wt. % filler in 75 wt. % chemical pulp, 8 wt. % titanium oxide used as a white pigment having a particle size of 5 μm, and having kaolin, and a rosin size or the like was added. It was confirmed that 7 g/m 2 of titanium oxide powder was contained in the finished product. The opaqueness of the paper was 94%, the whiteness degree 87%, and the air permeability 16 seconds. Next, in the full-color copying machine shown in FIG. 1, three color toners yellow, cyan and magenta, each of which has sharp melt properties, are adjusted so that the reflection density becomes 1.6 after being heat fixed, and the above three colors and three colors of blue, green and red as secondary colors are outputted in the form of a square patch whose one side is 30 mm. This image is color-identified visually from the surface opposite to the image. Three sheets of unused paper produced as described above were placed as a pad under the image. Regarding six color tones, yellow and other five colors could be barely identified visually, and the contour of the square patch was obscure. When an image was successively formed on the second side, satisfactory images on both sides were obtained without being affected by the image on the first side. The air permeability is a value measured by a method prescribed by JIS P8123, and is the time required for 100 ml of air to pass through an area of 645 mm 2 . Comparative Example 1 In comparison with the first embodiment, when a paper of an effective weight of 95 g/m 2 without containing titanium oxide was made so that paper of an opaqueness degree of 83%, a whiteness degree of 81% and an air permeability of 14 seconds can be obtained, and a six color patch similar to that described above was formed, it was possible to identify six colors from among all six colors. When a uniform yellow image with a reflection density of 0.8 was formed as the image on the second side, it was confirmed that the color was partially smeared by the color of the patch on the first side, and a blue patch portion became slightly blackened. EXAMPLE 2 In comparison with the first embodiment, a raw material containing 4 wt. % titanium oxide having a particle size of 10 μm was produced, a paper was made therefrom, having a density paper of 100 g/m 2 . The opaqueness degree of the was 92%, the whiteness degree thereof 85% and the air permeability thereof was 15 seconds. When an image was similarly formed on this paper, the number of identifiable patches was two. When a solid image of a yellow density of 0.8 was formed on the second side, it was nearly impossible to identify patches on the first side, there were no variations in the yellow color tone and thus a practical level was obtained. EXAMPLE 3 Paper weighing 75 g/m 2 and containing 3 g/m 2 of calcium carbonate powder was used as a base paper. By coating a coating solution of 50 wt. % magnesium oxide to 50 wt. % starch on both sides of the paper so that each paper weighs 10 g/m 2 when finished, a coating paper was obtained. As the total amount, 13 wt. % of fine white powder was contained. When finished, the opaqueness degree of the paper was 97%, the whiteness degree thereof was 86% and the air permeability thereof was 3,300 seconds. When the same image as in Example 1 was formed on this paper and offset was seen, each patch was concealed, and it was impossible to identify the patches, and no influence was exerted upon the image on a second side of the paper. Comparative Example 2 A raw material containing 20 wt. % of mechanical pulp within 60 wt. % of chemical pulp, in which 4 wt. % talc was internally added as a filler, as well as a sizing agent, starch and the like, was used to make paper having a thickness of 125 μm and weighing 100 g/m 2 . The opaqueness degree of the paper was 92% and the whiteness degree thereof was 78%. When an experiment for outputting an image similar to Example 1 was carried out on this paper, since the paper itself became blackened, the color tone of the image on a first side of the paper could hardly be observed from the rear side. However, since the whiteness degree of the paper itself was low, the yellow color decreases, and the quality as a full-color image decreased. Comparative Example 3 Paper was made which contains 60 wt. % chemical paper, 25 wt. % mechanical paper, and 6 wt. % calcium carbonate and talc as a filler, as well as starch and a sizing agent and water. The paper is 90 μm thick and weighs 75 g/m 2 . The opaqueness degree of this paper was 78%, and the whiteness degree thereof was 80%. When an experiment for outputting an image, similar to Example 1, was performed on this paper, the quality as a full-color image decreased because the paper itself became blackened and yellowed on a first side of the paper. Further, when a solid image having a yellow density of 0.6 was printed on a first side of the paper, and when a solid image having a blue image density of 0.3 was formed on a second side on the image of the second side, the second one was not blue but gray. It was determined to be an unsuitable paper for a full color on both sides of the paper. Many different embodiments of the present invention may be constructed without departing from the spirit and scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in this specification. To the contrary, the present invention is intended to cover various modifications and equivalent arrangements included with the spirit and scope of the claims. The following claims are to be accorded the broadest interpretation, so as to encompass all such modifications and equivalent structures and functions.
Transfer paper for outputting color images, suitable for use as a transfer member used in a color electrophotographic apparatus capable of forming a multi-color toner image by using at least two colors of single-color toner. The paper has a whiteness degree of 85% or more and an opaqueness degree of 90% or more. A method of forming a color image includes the steps of transferring a color toner image to transfer paper having a whiteness degree of 85% or more and an opaqueness degree of 90% or more, and heatingly fixing the color toner image.
Identify the most important aspect in the document and summarize the concept accordingly.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to transfer paper used in a color copying machine, in particular, a color electrophotographic apparatus having a double-side output capability, and to a method of forming color images by using the transfer paper.", "Description of the Related Art In recent years, an apparatus having full-color output capability and comprising a reader section R for reading a manuscript and a printer section P for outputting images in accordance with manuscript read signals, as shown in FIG. 1, is generally a type of laser printer.", "An image formation sequence of the apparatus in a case of a full-color mode will be explained briefly.", "Referring to FIG. 1, when a photosensitive drum 2 is rotated in the direction of an arrow B, a photosensitive member on the photosensitive drum 2 is uniformly charged by a charger 3.", "Next, image exposure is performed by a laser light E modulated in accordance with a yellow image signal of the color separation signals of a manuscript read by the reader section R, and an electrostatic latent image is thus formed.", "Next, as a rotor 4a rotates, the latent image is developed by a yellow developer 4Y which is moved to and fixed beforehand at a development position.", "Next, a transfer member housed within a cassette 101 or 102 is taken out of the cassette by a paper feeding roller 103 or 104, respectively.", "Further, the transfer member which has been passed through a paper feeding guide 4A, a paper feeding roller 106, and then a paper feeding guide 4B, is held by a gripper 6 at a predetermined timing, and then electrostatically wound around a transfer drum 8 by an abutment roller 7 and an electrode facing the abutment roller 7.", "The transfer drum 8 is rotated in the direction of an arrow A in synchronization with the photosensitive drum 2.", "The visual image developed by the yellow developer 4Y is transferred by a transfer charger 9 at a place where the outer peripheral surface of the photosensitive drum 2 abuts the outer peripheral surface of the transfer drum 8.", "The transfer drum 8 continues to rotate as it is so as to be ready for the transferring of the next color (magenta in FIG. 1).", "The electric charge of the photosensitive drum 2 is eliminated by a charger 10 for eliminating electric charge.", "After the photosensitive drum 2 is cleaned by cleaning means 11, it is charged again by a primary charger 3 and undergoes such image exposure as described above in accordance with the next magenta image signal.", "A rotary developing apparatus then rotates while an electrostatic latent image is formed on the photosensitive drum 2 in accordance with a magenta image signal as a result of the above-mentioned image exposure in order to position a magenta developer 4M at the above-mentioned predetermined development position and perform a predetermined magenta development.", "Then, the above-described process is performed for cyan and black colors.", "When the transfer of four colors has been completed, the electric charge of the four-color visual image formed on the transfer member is eliminated by the charger 10 and 13.", "Then, the transfer member is released by the gripper 6, is separated from the transfer drum 8 by a separation claw 14 and the transfer member is sent to a fixer 16 by a transport belt 15.", "The transfer member is then fixed by heat and pressure in the nip spacing formed by a fixing roller 161 whose surface is heated by a heating roller 163 and formed by a pressure roller 162, and then the transfer member is ejected onto a tray 17, thus completing a series of full-color print sequences.", "After the fixing roller 161 has finished fixing the transfer member, the roller is cleaned by a cleaning web 164 so as to be prepared for the next fixing operation.", "In forming color images using chromatic color toners based on such an electrophotographic method to reproduce a great number of colors, as described above, toners which are coloring powder of yellow, magenta, cyan and black are stacked on the transfer member in multiple layers, and a toner resin is melted by fixing so as to be mixed, that is, color mixing, thereby achieving the above purpose.", "For this reason, unlike printing using printing ink, a considerable amount of coloring pigment is placed on the paper which is a transfer member, thus causing the external-light shielding power to increase.", "Under such conditions, as regards a transfer member which can be used in a conventional full-color electrophotographic apparatus as paper formed from chemical pulp, there has been a demand that the transfer member has a proper degree of whiteness which serves as a base for color reproduction, is able to provide a low thermal capacity in which the above-mentioned color mixture by heating is possible, and has a volume resistivity in which electrostatic transferring of at least three times is possible, and having sufficient flexibility to allow the transfer member to be electrostatically wound around the transfer drum.", "These conditions may be satisfied by using plain paper, which paper generally has a whiteness degree of 85% or more, opaqueness degree of 85% or less, a volume resistivity of 1×10 10 to 10×10 11 Ω·cm (20° C., 65%), a stiffness of 17 to 22 cm (JIS P-8143 A process) though the plain paper has a weight slightly greater than that of ordinary black and white electrophotographic paper.", "The value of stiffness is measured in the following way.", "The length from the grasping portion to the leading edge of a test piece when the direction in which the leading edge of the test piece is hung and bent becomes an opposite direction if it is rotated 90° with the grasp line as an axis when one end of the test piece having a long thin, fixed shape is grasped and held upward, is the value of the stiffness.", "However, in a case in which a full-color image of only one surface is formed using the apparatus shown in FIG. 1 by use of the above-mentioned conventionally used paper, when a full-color image is formed nevertheless on both sides of the paper, there is the possibility that a color tone of the image on a second surface will be considerably affected depending upon the presence or absence of toner on the first surface of the paper when the paper is raised by the hiding power of the toner.", "Further, since the color of the first surface is made visible in the form of a watermark on a white portion on the second surface even if the first surface is a single image having a uniform density, chroma from a halftone portion to a highlight portion deteriorates considerably.", "Further, since the toner on the first surface is melted because fixing is performed twice, the toner deeply penetrates the paper, causing offset to increase.", "SUMMARY OF THE INVENTION It is an object of the present invention to provide transfer paper which is usable for a heating color-mixing type color image forming apparatus employing toner and particularly suitable for forming images on both sides of the paper, such paper being specialized for both-side use which does not produce considerable offset even when heat fixing is performed twice.", "It is another object of the present invention to provide a method of forming color images in which no offset is produced.", "The transfer paper for outputting color images in accordance with the present invention has a whiteness degree of 85% or more and a opaqueness degree of 90% or more.", "The whiteness degree is a value measured by a method prescribed in JIS P8123, which value being represented by a percentage (%) of the reflectance when blue to violet light of the spectrum is irradiated to a sample by using a Hunter whiteness degree tester with respect to the reflectance obtained when the same light is irradiated to a standard magnesium oxide plate.", "The opaqueness degree is a value measured by a method prescribed in JIS P8123.", "More specifically, the sample is backed up by a white and black standard plate, respective reflectances are measured via a green filter, the percentage (%) of the former with respect to the latter is represented as an opaqueness degree.", "A sample of 100% opaqueness degree is completely opaque paper.", "By using transfer paper having such whiteness or opaqueness degree, a color image having excellent color reproducibility and a small amount of offset can be formed.", "A transfer member is provided for a color electrophotographic apparatus capable of forming a multi-color toner image by use of at least two colors of single-color toner which comprises a transfer paper for outputting color images having a whiteness degree of 85% or more and an opaqueness degree of 90% or more, said paper containing 65 wt.", "% of chemical pulp.", "Objectives and advantages in addition to those discussed above shall be apparent to those skilled in the art from the description of the preferred embodiment of the invention which follows.", "In the description, reference is made to the accompanying drawings, which form a part hereof, and which illustrate examples of the invention.", "Such examples, however, are not exhaustive of the various embodiments of the invention, and therefore reference is made to the appended claims for determining the scope of the invention.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, longitudinal sectional view of a full-color electrophotographic copying machine in which the transfer paper for outputting color images in accordance with present invention can be used;", "and FIG. 2 is a graph illustrating the softening characteristics of sharp melt toner.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS It is preferable that transfer paper in accordance with the present invention be manufactured by adjusting the content of the fine white powder and the weight of the paper.", "Fine white powder is used to manufacture paper by mixing it with pulp, mixing it with a surface sizing material as surface processing components, or using it as a surface coating material.", "The content of the fine white powder is preferably 4 g or more per 1 m 2 of the paper.", "The fine white powder is preferably capable of reflecting light of the entire wavelength in the visible light region.", "The weight of the paper is preferably 90 g/m 2 or more, and more particularly 100 g/m 2 or more.", "The degree of whiteness can be made 90% by using fluorescent whitening dye in paper.", "Since such paper has a small internal scattering factor, the opaqueness is low, approximately 87%.", "When a patch image is formed by magenta, cyan, and yellow toners of an intensity of 1.6, and red, green and blue toners (made from a combination of two of the above magenta, cyan or yellow toners) on the image on the first side, and observed from the second side, than all six colors can be identified.", "The smaller the weight of the paper, the smaller the thermal capacity, and therefore color mixing by heating and melting toner can be efficiently performed.", "When this is done, the weight is preferably not more than 120 g/m 2 .", "There is an advantage in that this weight can be set at a small value by making opaqueness 90% or more by using fine white powder.", "The content of the chemical pulp which is a base material for the transfer member in accordance with the present invention is preferably 65 wt.", "% or more.", "Paper of 65 wt.", "% or more is preferable since it prevents the toner itself from being melted too much by the two-time fixing step for both sides of the paper and the paper fibers cannot be penetrated, though it depends upon the heat melting characteristics of the toner used for forming color images.", "The total amount of the content filler for increasing the degrees of opaqueness and whiteness is preferably 12 wt.", "% or more and, more preferably 14 wt.", "% or more.", "Preferably 4 g/m 2 , or more preferably 6 g/m 2 of fine white powder is contained in this amount.", "White pigment, such as titanium oxide, magnesium oxide, magnesium sulfate, or calcium carbonate, may preferably be used as the fine white powder.", "The particle size of the powder contained is preferably from 200 nm to 50 μm in terms of the average volume particle size and, more preferably, not more than 10 μm.", "The lower limit for the particle size may be that which allows powder in the form of secondary aggregated particles to be present.", "As primary particles, aggregatable particles, 20 mm or more in size, may be used.", "Regarding the contained form, classification may be made according to the finished form.", "Plain paper may be diffused uniformly along the thickness by internally adding paper raw material.", "When an objective paper in the form of a coated paper is to be obtained, a pulp raw-material and a coated layer may be separately added, or paper to which this powder is added may be used in the final coating.", "When the transfer paper of the present invention is used to form a color image, sharp melt toner having a low softening point and a low melt viscosity is used because there is a demand for excellent melting properties and color mixing properties when heat is applied.", "This is because use of such sharp melt toner makes it possible to widen the range in which colors of a copy are reproduced, and to obtain a color copy close to the broad range of colors of the manuscript or a full-color image.", "Such sharp melt toner is manufactured by melt kneading, grinding, and classifying materials for forming toner, such as a binding resin like polyester resin or styrene-acrylic ester resin, a coloring agent (dye, sublimating dye), or a charge control agent.", "If necessary, an external addition step for adding various external addition agents (e.g., hydrophobic colloidal silica) to a toner may be performed.", "For such a color toner, use of a polyester resin as a binding resin is particularly preferred when binding and sharp melt properties are considered.", "An example of a sharp melt polyester resin is a high polymer compound having ester binding in the principal chain of molecules synthesized from a diol compound and carboxylic acid.", "In particular, a polyester resin which has bisphenol represented by the following formula: ##STR1## (R is the ethylene or propylene group, x and y are each a positive integer of 1 or more, and the average value of x+y is from 2 to 10), or a polyester resin which has a substituted product thereof as diol components, is preferable because the polyester resin has sharp melting characteristics, in which divalent or higher-valence carboxylic acid, acid anhydride thereof, carboxylic acid components thereof formed of lower alkyl ester (e.g., fumaric acid, maleic acid, maleic acid anhydride, phthalic acid, terephthalic acid, trimellitic acid, or pyromellitic acid) are at least copolycondensed.", "The softening point of the polyester resin is preferably 75° to 150° C. and, more preferably, 80° to 120° C. An example of the softening characteristics of the sharp melt toner containing this polyester resin as a binding resin is shown in FIG. 2. The measuring conditions are as follows.", "The CFT-500A type flow tester (manufactured by Shimazu Corp.) was used.", "The amount of the plunger descent amount/temperature curve (hereinafter referred to as a softening S-shape curve) of the toner was determined, when a die (nozzle) was 0.2 mm in diameter and 1.0 mm in thickness, an extrusion load of 20 kg was applied, at an initial set temperature of 70° C., heated at an even speed of 6° C./minute after a lapse of 300 seconds of warming up.", "One (1)g to three (3)g of precisely weighed fine powder was used to sample the toner.", "The cross section of the plunger was set to 1.0 cm 2 .", "The softening S-shape curve becomes the curve shown in FIG. 2. As it is heated at an even speed, the toner is heated gradually, and begins to flow out (the plunger descends A→B) .", "Further, when the temperature increases, a substantial amount of molten toner flows out (B→C→D), the plunger stops descending and terminates (D→E).", "The height H of the S-shape curve indicates the total amount of flowout, and the temperature T0 corresponding to the C point of H/2 indicates the softening point of the toner.", "Whether the toner and the binding resin have sharp melt properties can be determined by measuring the apparent melt viscosity of the toner and the binding resin.", "Toners and binding resins having sharp melt properties are ones which satisfy the following conditions, when the temperature at which the apparent melt viscosity shows 10 3 poise is denoted as T1, and the temperature at which the apparent melt viscosity shows 5×10 2 poise is denoted as T2: T1=90° to 150° C. |ΔT|=|T1-T2|=5° to 20° C. The sharp melt resin having these temperature/melt viscosity characteristics has a feature that when it is heated, the viscosity thereof decreases very sharply.", "Such decrease in viscosity causes the uppermost toner layer to be appropriately mixed with the bottommost toner layer, causes the transparency of the toner layer itself to increase sharply, thereby causing satisfactory color subtraction mixing.", "EXAMPLE 1 Paper having a thickness of 135 μm and weighing 130 g/m 2 was made by using raw-material pulp containing 16 wt.", "% filler in 75 wt.", "% chemical pulp, 8 wt.", "% titanium oxide used as a white pigment having a particle size of 5 μm, and having kaolin, and a rosin size or the like was added.", "It was confirmed that 7 g/m 2 of titanium oxide powder was contained in the finished product.", "The opaqueness of the paper was 94%, the whiteness degree 87%, and the air permeability 16 seconds.", "Next, in the full-color copying machine shown in FIG. 1, three color toners yellow, cyan and magenta, each of which has sharp melt properties, are adjusted so that the reflection density becomes 1.6 after being heat fixed, and the above three colors and three colors of blue, green and red as secondary colors are outputted in the form of a square patch whose one side is 30 mm.", "This image is color-identified visually from the surface opposite to the image.", "Three sheets of unused paper produced as described above were placed as a pad under the image.", "Regarding six color tones, yellow and other five colors could be barely identified visually, and the contour of the square patch was obscure.", "When an image was successively formed on the second side, satisfactory images on both sides were obtained without being affected by the image on the first side.", "The air permeability is a value measured by a method prescribed by JIS P8123, and is the time required for 100 ml of air to pass through an area of 645 mm 2 .", "Comparative Example 1 In comparison with the first embodiment, when a paper of an effective weight of 95 g/m 2 without containing titanium oxide was made so that paper of an opaqueness degree of 83%, a whiteness degree of 81% and an air permeability of 14 seconds can be obtained, and a six color patch similar to that described above was formed, it was possible to identify six colors from among all six colors.", "When a uniform yellow image with a reflection density of 0.8 was formed as the image on the second side, it was confirmed that the color was partially smeared by the color of the patch on the first side, and a blue patch portion became slightly blackened.", "EXAMPLE 2 In comparison with the first embodiment, a raw material containing 4 wt.", "% titanium oxide having a particle size of 10 μm was produced, a paper was made therefrom, having a density paper of 100 g/m 2 .", "The opaqueness degree of the was 92%, the whiteness degree thereof 85% and the air permeability thereof was 15 seconds.", "When an image was similarly formed on this paper, the number of identifiable patches was two.", "When a solid image of a yellow density of 0.8 was formed on the second side, it was nearly impossible to identify patches on the first side, there were no variations in the yellow color tone and thus a practical level was obtained.", "EXAMPLE 3 Paper weighing 75 g/m 2 and containing 3 g/m 2 of calcium carbonate powder was used as a base paper.", "By coating a coating solution of 50 wt.", "% magnesium oxide to 50 wt.", "% starch on both sides of the paper so that each paper weighs 10 g/m 2 when finished, a coating paper was obtained.", "As the total amount, 13 wt.", "% of fine white powder was contained.", "When finished, the opaqueness degree of the paper was 97%, the whiteness degree thereof was 86% and the air permeability thereof was 3,300 seconds.", "When the same image as in Example 1 was formed on this paper and offset was seen, each patch was concealed, and it was impossible to identify the patches, and no influence was exerted upon the image on a second side of the paper.", "Comparative Example 2 A raw material containing 20 wt.", "% of mechanical pulp within 60 wt.", "% of chemical pulp, in which 4 wt.", "% talc was internally added as a filler, as well as a sizing agent, starch and the like, was used to make paper having a thickness of 125 μm and weighing 100 g/m 2 .", "The opaqueness degree of the paper was 92% and the whiteness degree thereof was 78%.", "When an experiment for outputting an image similar to Example 1 was carried out on this paper, since the paper itself became blackened, the color tone of the image on a first side of the paper could hardly be observed from the rear side.", "However, since the whiteness degree of the paper itself was low, the yellow color decreases, and the quality as a full-color image decreased.", "Comparative Example 3 Paper was made which contains 60 wt.", "% chemical paper, 25 wt.", "% mechanical paper, and 6 wt.", "% calcium carbonate and talc as a filler, as well as starch and a sizing agent and water.", "The paper is 90 μm thick and weighs 75 g/m 2 .", "The opaqueness degree of this paper was 78%, and the whiteness degree thereof was 80%.", "When an experiment for outputting an image, similar to Example 1, was performed on this paper, the quality as a full-color image decreased because the paper itself became blackened and yellowed on a first side of the paper.", "Further, when a solid image having a yellow density of 0.6 was printed on a first side of the paper, and when a solid image having a blue image density of 0.3 was formed on a second side on the image of the second side, the second one was not blue but gray.", "It was determined to be an unsuitable paper for a full color on both sides of the paper.", "Many different embodiments of the present invention may be constructed without departing from the spirit and scope of the present invention.", "It should be understood that the present invention is not limited to the specific embodiments described in this specification.", "To the contrary, the present invention is intended to cover various modifications and equivalent arrangements included with the spirit and scope of the claims.", "The following claims are to be accorded the broadest interpretation, so as to encompass all such modifications and equivalent structures and functions." ]
BACKGROUND OF THE INVENTION This invention relates to head loading systems, and more particularly, to a head loading system of a magnetic disc apparatus or flexible disc apparatus, capable of moving toward and away from an information recording medium at least one magnetic head for at least reproducing information recorded on such information recording medium. Generally a magnetic disc apparatus or flexible disc apparatus comprises a head loading system for moving at least one magnetic head serving as an information reproducing head toward and away from a magnetic disc functioning as a recording medium for recording information therein. The head loading system comprises a magnetic head support mechanism for supporting the magnetic head in juxtaposed relation to one surface of the magnetic disc, and a head loading actuator for driving the magnetic head support mechanism to move the magnetic head toward and away from the surface of the magnetic disc. A magnetic head support mechanism of a magnetic head loading system of the prior art will be described by referring to FIGS. 1(a) to 2(b). The magnetic head support mechanism of the head loading system shown in FIGS. 1(a) and 1(b) comprises a gimbaled spring 4 for resiliently supporting a magnetic head 1a jaxtaposed against a top surface of a magnetic disc 6, a swing arm 3a for supporting the gimbaled spring 4 for vertical movement and supporting a hook 5 at one end portion and a downwardly projecting cam 7a at the other end portion, a swing arm 3b mounting at one end portion a magnetic head 1b in juxtaposed relation to a bottom surface of the magnetic disc 6 and having at the other end portion an upwardly extending cam 7b which is brought into engagement with the cam 7a, a support portion 50 for supporting the swing arms 3a and 3b through support springs 2, respectively, and preloading springs 8a and 8b extending from the support portion 50 to urge the swing arms 3a and 3b respectively to move in a direction in which they are closed. The numeral 9 designates a bail for moving the hook 5 vertically which constitute a part of the magnetic head loading actuator subsequently to be described. When the magnetic heads 1a and 1b are respectively located close to the top and bottom surfaces of the magnetic disc 6, the magnetic head support mechanism is located such that, as shown in FIGS. 1(a) and 1(b), the bail 9 has its forward end 9a spaced apart from the hook 5 because it is located in a lower position. As the swing arms 3a and 3b are pressed by the preloading springs 8a and 8b respectively, the magnetic heads 1a and 1b are moved to positions in which they are close to the top and bottom surfaces of the magnetic disc 6 respectively. In the head loading system of the aforesaid construction, the head loading actuator is operative to cause the forward end 9a of the bail 9 to lift the hook 5 to thereby cause the magnetic head 1a supported by the swing arm 3a through the gimbaled spring 4 to move away from the top surface of the magnetic disc 6, as shown in FIGS. 2(a) and 2(b). As the cam 7a moves leftwardly to press the cam 7b of the arm 3b to move it leftwardly in the figure in the process of the movement of the swing arm 3a in the clockwise direction, the swing arm 3b moves in the counterclockwise direction to move the magnetic head 1b supported by the arm 3b away from the magnetic disc 6. Upward movement of the bail 9 causes the parts in positions shown in FIG. 1(a) to shift to positions shown in FIG. 2(a). The operation characteristic of the bail 9 is very important because it would exert influences on (1) the speed of response of the head loading system to an external signal and (2) the damage which the magnetic disc and the magnetic heads might suffer when the latter strike the former. Particularly in recent years, the head loading actuator of a head loading system is required to have the following functions: (1) To respond quickly to an external signal and move the magnetic heads near to or into intimate contact with the magnetic disc in a very short period of time; (2) To avoid damage which the magnetic disc might suffer when the magnetic heads strike same by causing the latter to come into contact with the former gently; and (3) To perform the aforesaid operations with minimized energy. To cope with this situation, head loading systems of the prior art use a head loading actuator shown in FIG. 3. The head loading actuator shown in the figure comprises a push-pull solenoid 12 including a plunger 13, a coil 14 and a fixed pole 16, the bail 9 having one end adapted to come into engagement with the hook 5, and a return spring 11. The bail 9 has a central portion pivotally connected to the plunger 13 of the solenoid 12 and is adapted to come into engagement at the forward end 9a with the hook 5 while it is pullsed at its rear end by the return spring 11 to be pivoted at a pin 10. As an energizing current is passed to the coil 14, the solenoid 12 is energized and pulls the plunger 13 downwardly against the biasing force of the return spring. This causes the bail 9, pivotally connected to the plunger 13, to move in the clockwise direction about the pin 10 to move downwardly the hook 5 in engagement with the forward end 9a of the bail 9. Upon interruption of the supply of the energizing current to the coil 14, the bail 9 is moved in the counterclockwise direction by the biasing force of the return spring 11 about the pin 10 to move the hook 5 upwardly in the figure. By these operations, the head loading actuator moves vertically up and down the hook 5 of the magnetic head support so as to thereby move the magnetic heads toward and away from the magnetic disc. FIG. 4 shows the relation between the stroke and the attracting force of the solenoid 12 that can be established when the energizing current passed to the coil 14 is constant. In FIG. 4 the figure, it will be seen that in the process of movement of the forward end of the plunger 13 from an upper-most position (starting point 15a) of a stroke of 3 mm to a lowermost position (terminating point 15b) of a stroke of 0, the attracting force increases rapidly non-linearly from about 0.3 kg to 2.5 kg as indicated by an arrow C. The phenomenon that the attracting force increases with a reduction in stroke would be accounted for by the fact that, as the plunger 13 is attracted by the magnetic force and moves downwardly as shown in FIG. 3, the gap δ decreases and the magnetic flux density in the gap δ increases while the area spacing the plunger 13 away from the coil 12 increases. FIG. 5 shows the stroke/load characteristic of the head loading system in which the stroke represents an overall resilience of the system including the biasing force of the return spring 11 of the head loading actuator and the biasing forces of the preloading springs 8a and 8b of the head support mechanism. As the stroke decreases from a condition (starting point 15c) in which the forward end 9a of the bail 9 is in engagement with the hook 5, the load increases little by little until a point D is reached at which the magnetic heads are brought into contact with the surfaces of the magnetic disc and the bail 9 is released from engagement with the hook 5 when the load decreases once, but thereafter the load increases little by little as balance is restored between the load and the force of restitution of the return spring 11 until a terminating point 15d is reached. FIG. 6 shows the characteristic of FIG. 4 combined with the characteristic of FIG. 5. As shown in FIG. 6, it is necessary that an attracting force curve 100 of the solenoid 12 be higher at all times than a load curve 200 to allow the magnetic heads to move away from the magnetic disc, and the solenoid 12 would be inoperative if the attracting force is low as indicated by an attracting force curve 101. Attention is directed to FIGS. 4-6 in which the attracting force shown is obtained by continuously passing an energizing current of a constant value to the coil 12. In actual practice, the attracting force would show variations in a transition state in passing an energizing current of a constant value to the coil of an actual apparatus. The variations occurring in the attracting force in the transient state are as follows: (a) Assuming the magnetic field in the gap δ between the plunger 13 of the push-pull solenoid 12 and the fixed pole 16 is H(AT/m), and the magnetic flux density and the area thereof is B(WB/m 3 ) and A(m 2 ) respectively. Then, the attracting force F (kg) can be expressed by the following equation: ##EQU1## Assuming the magnetic permeability is μo, then the magnetic flux density B can be expressed by the following equation: B=μo.H (2) Thus, equation (1) can be rewritten as equation (3) as follows: ##EQU2## Assuming the constant is determined by the construction of the solenoid 12, and number of turns of the coil 14 and the energizing current are K, N and I, respectively, then the magnetic field H can be expressed by the following equation: H=K.N.I (4) From equations (3) and (4), the attracting force F can be expressed by the following equation: ##EQU3## Thus, when the constant determined by the construction of the solenoid 12 and the number of turns of the coil 14 is denoted by A o , it will be seen that the attracting force of the plunger of the solenoid of the predetermined shape is proportional to the square of the energizing current I as shown by the following equation: F=A.sub.o.I.sup.2 ( 6) where ##EQU4## (b) However, when the inductance and the internal resistance of the coil 14 are denoted by L and R, respectively, and a step voltage E o is impressed thereon, the energizing current will rise with an inclination of L/R with time and draw near E o /R, as shown in the following equation and FIGS. 7(a) and 7(b): ##EQU5## (c) Thus, as can be clearly seen in equations (6) and (7), a change with time of the attracting force in an actual apparatus has a characteristic such that the attracting force suddenly increases as indicated by an attracting force curve 110 shown in FIG. 8 as well as the following equation (8): ##EQU6## The stroke/attracting force characteristic shown in FIG. 8 indicates that since the attracting force 110 rises suddenly the plunger 13 has a very high acceleration when the stroke is 0. Because of this, there are great possibilities that the magnetic heads 1a and 1b would be forced, by the very high acceleration, to strike the magnetic disc 6 to cause damage to both the magnetic disc 6 and the magnetic heads 1a and 1b, since in an apparatus of the prior art, the hook 5 in engagement with the forward end 9a of the bail 9 would have its movement greatly accelerated. Moreover, the head loading system of the prior art has the problems in that a stopper 17 strikes a top surface of the solenoid 12 with a high force and produces a large noise, and that the solenoid 12 has a high consumption of electric power because it is necessary to place a string point 15e shown in FIG. 8 in a relatively high position. Additionally, the solenoid is located perpendicular to the planes of surfaces of the magnetic disc in the head loading system of the prior art, making it necessary for the apparatus to have, in addition to the vertical dimension of the solenoid, a vertical dimension that would enable the bail 9 and hook to move vertically upwardly away from the upper end of the solenoid. Thus, it has been impossible to reduce the vertical dimension of the head loading system, and consequently difficulties have been experienced in obtaining a magnetic disc apparatus of small thickness. A head loading actuator similar to the one shown in FIG. 3 is disclosed in Japanese Patent Application Laid-Open No. 58311/76 corresponding to U.S. Ser. No. 510,471, now U.S. Pat. No. 3,973,274 for example. In order to obviate the problems raised by the head loading actuator of the head loading system of the prior art of the aforesaid construction, attempts have been made by us to adopt the following measures: (i) The head loading actuator would have a solenoid which would, as shown in FIG. 9, be constructed such that the plunger 13 would have a lower end projecting downwardly in the form of a cone and the fixed pole 16 would have a shape complementary with the aforesaid shape of the lower end of the plunger 13, to thereby reduce as much as possible a sudden change in the attracting force by minimizing a sudden change in the magnetic flux density and the opposed surfaces of the plunger 13 and the coil 14. (ii) The head loading actuator would have a construction such that the point of connection between the bail 9 and the plunger 13 would be moved from the position shown in FIG. 3 to a position closer to the pin 10 serving as the pivot for the bail 9, to minimize the influences which might be exerted by a sudden change in the attracting force by decreasing the stroke of the plunger 13. (iii) The head loading actuator would have a construction such that the push-pull solenoid 12 would have an electrical damping function or a hydraulic damping function. However, it has been ascertained that some disadvantages are associated with various constructions of the head loading actuator described hereinabove. The solenoid construction described in paragraph (i) has proved, upon experiments, to have no marked improvement in operation characteristic. The head loading actuator described in paragraph (ii) could achieve no excellent effects because the compactness of the apparatus makes it impossible to increase the lever ratio l 0 /l 1 (FIG. 3) of the bail 9. In the head loading actuator provided with a damper as described in paragraph (iii), the reliability of the apparatus as a whole would be lowered due to obturation of the damper and the short service life thereof, thereby making the apparatus of no practical value. Thus, it has been ascertained that no satisfactory operation characteristic can be obtained even if some improvements were provided in a head loading system of the prior art wherein the plunger and the bail are directly connected together. SUMMARY OF THE INVENTION This invention has been developed for the purpose of obviating the aforesaid disadvantages of the prior art. Accordingly an object of the invention is to provide a head loading system capable of moving the magnetic heads at high speed and yet bringing them into contact with a recording medium lightly with a soft tough. Another object is to provide a head loading system capable of operating its head loading actuator with a minimum of consumption of electric power to thereby save energy. A further object is to provide a head loading system enabling an information reproducing apparatus to have a small overall thickness. According to the invention, there is provided a head loading system comprising a head support mechanism for supporting magnetic heads in juxtaposed relation to surfaces of a recording medium, and a head loading actuator for driving the head support mechanism, the head loading actuator comprising a solenoid including a plunger and located horizontally with respect to the surfaces of the recording medium, and motion converting means connected to the plunger capable of converting a linear motion of the plunger caused by the solenoid into a rotary motion and also capable of changing the motion conversion constant. The motion converting means of the head loading system according to the invention may comprise a motion converting portion connected to a shaft of the solenoid, rotary disc formed on a surface thereof juxtaposed against the solenoid a plurality of grooves each having a varying depth, an inner frame of the solenoid formed in positions corresponding with the grooves of the rotary disc with a plurality of grooves each having a varying depth, and a ball fitted in the grooves of the rotary disc and the grooves of the inner frame of the solenoid. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) and 1(b) are respectively a front view and a side view of a magnetic head support mechanism of a magnetic head loading system of a prior art with the magnetic heads being moved toward the magnetic disc; FIGS. 2(a) and 2(b) are respectively a front view and a side view of a magnetic head support mechanism of a magnetic head loading system of the prior art with the magnetic heads moving away from the magentic disc; FIG. 3 is a sectional view of ahead loading actuator of a magnetic head loading system of the prior art; FIG. 4 is a digrammatic representation of the attracting force/stroke characteristic of the head loading actuator shown in FIG. 3; FIG. 5 is a diagrammatic representation of the load/stroke characteristic of the head loading actuator shown in FIG. 3; FIG. 6 is a diagrammatic representation of the attracting force and the load in relation to the stroke of the head loading acturator shown in FIG. 3; FIG. 7(a) and 7(b) are diagrammatic representations of the relationship between the voltage impressed on the head loading actuator shown in FIG. 3 and the electric current; FIG. 8 is a diagrammatic representation of the attracting force and the load in relation to the stroke of a solenoid of the prior art determined by taking the impressed voltage into consideration; FIG. 9 shows a solenoid that has come to the mind of the inventor; FIG. 10 is a prespective view of one embodiment of the head loading actuator of the magnetic head loading system in conformity with the invention; FIG. 11 is a side view of the head loading actuator shown in FIG. 10; FIG. 12 shows the rotary disc of the head loading actuator shown in FIGS. 10 and 11; FIG. 13 is a view in explanation of the operation of the bail and the roller of the head load actuator shown in FIGS. 10 and 11; FIG. 14 is a diagrammatic representation of the attracting force and the load in relation to the stroke of the solenoid of the head loading actuator according to the invention; FIGS. 15 and 16 show the rotary disc and the inner frame of the motion converting portion of the head loading actuator according to the invention; FIG. 17 shows a modification of the motion converting portion of the head loading actuator according to the invention; FIG. 18 is a diagrammatic representation of gap/stroke characteristic of the solenoid of the head loading actuator according to the invention; FIG. 19 is a view showing the relation between the energizing current to the solenoid of the head loading actuator according to the invention and the signal reproduced by the magnetic head; FIG. 20 is a view showing the relation between the energizing current of a solenoid of a head loading actuator of the prior art and the signal reproduced by the magnetic head; and FIGS. 21 and 22 show the motion converting portion of the head loading actuator according to the invention for converting a linear motion of the solenoid into a rotary motion of the rotary disc. DETAILED DESCRIPTION FIG. 10 is a perspective view of the head loading actuator of the head loading system comprising a preferred embodiment of the invention. As shown, the head loading actuator comprises a bail 90 pivotable about the pin 10 which includes forward end portion 90a adapted to engage the hook 5 of the head support mechanism, a push-pull solneoid 125 including a plunger 130 which produces a linear motion for moving the plunger 130 in a straight line, and motion converting means for converting the linear motion of the plunger 130 into a rotary motion to move the forward end portion 90a of the bail 90 up and down. The motion converting means comprises a rotary member 18 for converting the linear motion of the plunger 130 into the rotary motion, and a pin 22 and a roller 23 for transmitting the rotary motion of the rotary member 18 to the bail 90, and is operative to move the forward end portion 90a of the bail 90 substantially vertically. FIG. 11 shows one side of the head loading actuator shown in FIG. 10. The push-pull solenoid 125 comprises a fixed pole 160, a coil 140, the plunger 130, a guide shaft 135 mounted for rotation in a center hole of the fixed pole 160 for supporting the plunger 130, a coil spring 21 mounted between one end of the guide shaft 135 and a solenoid outer frame 136 for biasing the guide shaft 135 in a predetermined direction, and a frame 137 enclosing the coil 140 and formed at its front surface with guide grooves 19a subsequently to be described. The rotary member 18 constituting a part of the motion converting means is mounted on the front surface of the plunger 130 to cooperate therewith and formed, at one portion of an inner surface 138, with grooves 19b of a shape subsequently to be described. The rotary member 18 has projecting form its outer surface the pin 22 having the roller 23 rotatably mounted at its forward end. The roller 23 is fitted in a bail groove 24 formed in a lower portion of the bail 90 for moving the bail 90 up and down as the rotary member 18 rotates. A bearing 20 is mounted between the grooves 19b of the rotary member 18 and the guide grooves 19a of the frame 137. Upon the plunger 130 being attracted to the pole 160 following energization of solenoid 125, the bearing 20 moves along the grooves 19a and 19b in a manner to allow the plunger 130 to move rightwardly. Movement of the bearing 20 causes the rotary member 18 and the plunger 130 to rotate, as subsequently to be described. FIG. 12 is a view showing the rotary member 18 as viewed from the direction of the inner surface 138. In this embodiment, the rotary member 18 is in the form of a disc and formed along its circumference with the three grooves 19b each of which is constructed such that its depth successively increases in going from one end of each groove toward the other end thereof as viewed from the side of the member 18. FIG. 13 which shows the bail 90, as viewed in the direction of an arrow D in FIG. 10, is a view in explanation of the relationship between the movement of the roller 24 and the pivotal movement of the bail 90 about the pin 10 occasioned by the rotation of the rotary member 18 of the head loading actuator of the aforesaid construction. In FIG. 13, the roller 23 extending from the rotary member 18 is fitted in the bail groove 24 formed at the lower end of the bail 90. Thus as the roller 23 moves with the rotation of the rotary member 18, the bail 90 moves pivotally about the pin 10. At this time, the engaging portion 90a of the bail 90 would move in rotary motion, strictly speaking. However, it is spaced apart from the pin 10 serving as the pivot in this case by a distance l and has a very small stroke S. Thus, when the angle of pivotal movement of the bail 90 is denoted by θ, the forward end portion 90a moves substantially in a linear motion. For example, let the stroke of the forward end of the bail 90 necessary to accomplish the desired end, the distance from the center of the pin 10 to the forward end of the bail 90, the distance from the center of the pin 10 to the rolling center of the roller 23 in the bail groove 24, the angle of pivotal movement of the bail 90, the distance from the center of the pin 10 to the center of rotation of the rotary disc 18, the angle formed by a line parallel to the X axis of the Axes X and Y crossing perpendicular to each other at the pin 10 and a line extending through the center of the rotary disc 18 and the center of the pin 22, located at its home position the angle through which the rotary disc 18 further rotates from the aforesaid angle formed by the X axis with the centers of the rotary disc 18 and the pin 22, and the distance between the center of the rotary disc 18 and the center of the pin 22 be denoted by S, l, R, θ, D, α o , α , and γ, respectively. Then the angle of pivotal movement of the bail 90 and the lever ratio β can be expressed by the following equations: θ=S/l (9) β=l/R (10) Furthermore, let the linear/rotary motion conversion constant decided by the angle of the grooves be denoted by a o . Then the angle of rotation of the rotary disc 18 and the gap δ of the solenoid 125 can be expressed by the following equation: α=a.sub.o.δ (11) Thus, the relation between the gap δ of the solenoid 125 and the stroke S can be expressed by the following equation (12): ##EQU7## Since the lever ratio β, the distance γ and the constant a o are decided by the structural dimensions, equation (12) shows that the necessary stroke S of the engaging portion 90a of the bail 90 and the gap δ of the solenoid 125 are proportional to each other using as a constant one of different types of variable values. For example, the stroke S' and the gap δ' of the head loading drive section shown in FIG. 3 are proportional to each other only using the lever ratio β' as a constant as shown in the following equation (13): S'=β'.δ' (13) In view of the limitations placed on the dimensions of the apparatus, it has been impossible to impart a sufficiently large value to the lever ratio β' and, consequently, the head loading drive section of the prior art has hitherto been unable to give a sufficiently large value to the stroke S'. The lever ratio β' is required to be based on a high dimensional accuracy because the distance covered by the movement of the plunger of the solenoid would be increased only by the lever ratio β'. However, in the embodiment of the invention described hereinabove, the head loading actuator is able, as shown in FIG. 12, to impart a large value to the stroke S of the engaging portion 90a of the bail 90 even if the gap δ is small or the amount of movement of the plunger 130 is small, by increasing the constant a o which is decided by the angle of the grooves 19a and 19b, in the even that the distance γ has a small value due to the need to reduce the thickness of the apparatus. Considering a case in which the stroke S=S'=3 mm. In this case, the value of the gap δ is required to be 1.5 mm in the prior art because the lever ratio β'=2. In the embodiment described hereinabove, it will be seen that the gap δ can be reduced to about 1/3 the value obtained in the prior art as indicated by the following equation, with the lever ratio β'=1.2, the distance γ=13.5 and the constant a o =0.37 rad/mm: ##EQU8## Thus, it will be appreciated that the push-pull solenoid 125 is able to operate in a position in which the attracting force undergoes little change with respect to the stroke. Moreover, since the head loading actuator according to the invention is capable of operation in a positoin in which the attracting force of the push-pull solenoid 125 undergoes little change with respect to the stroke S of the plunger, it is possible to reduce the operation velocity of the bail 9 by taking the following measures: According to Faraday's law, a voltage e generated at opposite ends of a winding is related to a change in time of a magnetic field H and the number of turns. The relation can be expressed by the following equation (14): ##EQU9## By modifying equation (14) and performing bilateral integration, the following equation (15) can be obtained: ##EQU10## Here, as shown by equation (3), the attracting force F of the push-pull solenoid 125 can be expressed by the following equation (16) by substituting equation (15) into equation (13): ##EQU11## Equation (16) indicates the following: (i) The attracting force increases with time integration of the impressed voltage. Thus, stepwise impression of a voltage would causes the attracting force to gradually increases with time as shown in FIG. 7a. (ii) The change with time in attracting force, particularly its rise characteristic, could be varied by the number of turns N of the winding, thereby enabling rise to be achieved smoothly. This would make it possible to design a magnetic head loading system in which the attracting force does not show an excessively large change with respect to a change in the gap δ of the push-pull solenoid or the stroke of the bail 90. FIG. 14 is a diagrammatic representation of the attracting force/load characteristic in relation to the stroke characteristic of the embodiment shown in FIG. 10. It will be seen that an attracting force curve 300 and a load curve 200 at the forward end of the bail in relation to the stroke characteristic indicate a marked improvement as compared with those shown in FIG. 6. Operation of the head loading actuator of the magnetic head loading system shown in FIG. 10 of the aforesaid construction will be described. In the head loading actuator shown in FIGS. 10 and 11, the coil spring 21 urges the guide shaft 135 to move leftwardly in the figure by its force of restitution when no energizing current is passed to the solenoid 125. The coil spring 21 is operative to unload the magnetic heads by pressing the plunger 130 when the energizing current is cut off. In this condition, a space x 1 is formed between the frame 137 of the plunger 125 and the inner surface 138 and the bearing 20 is positioned in the smaller depth portions of the grooves 19a and 19b. FIG. 15 shows, in a fragmentary sectional view, the rotary member 18 and the frame 137 as viewed longitudinally of the grooves 19a and 19b in the aforesaid condition. It will be clearly seen that the ball 20 is positioned in the small depth portions of the grooves 19a and 19b. At this time, the rotary disc 18 causes by its rotation the pin 22 to be disposed in a relatively high position as shown in FIG. 21. Thus, the roller 23 connected to the pin 22 pushes the forward end portion 90a of the bail 90 upwardly as shown in a broken line in FIG. 13, to thereby push upwardly the hook 5 of the magnetic head support mechanism. In this condition, the magnetic heads 1a and 1b are away from the magnetic disc 6 as shown in FIGS. 2(a) and 2(b). When it is desired to move the magnetic heads toward the magnetic disc, a current is passed to the solenoid 125 of the head loading actuator to attract the plunger 130 supported by the guide shaft 135 to the fixed pole 160. The attracting force of the solenoid 125 tends to move the bearing 20 to large depth portions of the grooves 19a and 19b. This makes the rotary member 18 move in the direction of an arrow E 1 shown in FIG. 21 as the bearing 20 rotates, so that the rotary member 18 rotates in the direction of an arrow E 2 as the bearing 20 moves. In this fashion, the motion converting mechanism of the embodiment first converts a linear motion of the plunger 130 of the solenoid 125 into a rotary motion of the rotary disc 18. When the plunger 130 reaches its terminating position of its movement caused by the attracting force of the plunger 125, the bearing 20 is located in the maximum depth portions of the grooves 19a and 19b as shown in FIGS. 22 and 16. With the bearing 20 in this position, the rotary member 18 and the frame 137 are disposed close to each other with a spacing of x 2 therebetween. At this time, the pin is moved by the rotation of the rotary member 18 to its lowermost position, and causes the engaging portion 90a of the bail 90 to move downwardly to a position in which it is released from engagement with the hook 5, as shown in solid lines in FIG. 13. The movement of the forward end portion 90a of the bail 90 when the magnetic heads 1a and 1b are moved toward the magnetic disc 6 will be described. FIG. 18 shows the relation between the stroke of the forward end portion 90a and the gap δ of the solenoid 125. As shown in the figure, the stroke of the forward end portion 90a of the bail 90 of the embodiment can vary linearly as indicated by a characteristic line 500 shown in a broken line from a starting point 15e at which the gap δ of the solenoid 125 is 0.5 mm to a terminating point 15d at which the gap δ is 0 mm. Thus, the head loading actuator of the embodiment enables the stroke of the forward end portion 90a of the bail 90 to be increased to 3 mm by using the stroke of 0.5 mm of the solenoid 125. This is supported by equation (14). In the head loading actuator according to the invention, the loading characteristic can be controlled by the configuration of the grooves 19a and 19b. For example, by imparting a smoothly curved surface to each of the grooves 19a and 19b as shown in FIG. 17, it is possible to cause the stroke of the forward end portion 90a of the bail 90 to vary in a curve as shown by a line 400 in FIG. 18. When this is the case, the head loading actuator can operate such that the movement of the magnetic heads can be slowed down as they draw near the magnetic head. FIG. 19 shows the results of experiments conducted on the change-with-time characteristic of an energizing current 600 of the solenoid 125 of the head loading actuator of the embodiment and a reproducing signal 700 of the magnetic heads detected in the loading process, and FIG. 20 shows the change-with-time characteristic of an energizing current 800 and a reproducing signal 900 of a head loading actuator of the prior art. It will be seen in FIGS. 19 and 20 that the head loading actuator according to the invention is capable of operation with the energizing current 600 of 110 mA which is about one half that of the energizing current 800 of the prior art shown in FIG. 20, and that the energizing current 600 and the reproducing signal 700 of the magnetic heads has a characteristic such that they successively increase with time, indicating that the magnetic heads can move toward the magnetic disc slowly. The fact that the energizing current required by the head loading actuator according to the invention is small offers the advantages that the head loading actuator has a low electric power consumption level and generates little heat. The fact that the magnetic heads moves slowly toward the magnetic disc offers the advantages that damage that might otherwise be caused to the magnetic heads and magnetic disc as the former suddenly strike the latter with a high force and that the head loading system having the solenoid arranged horizontally can have its thickness reduced. By virtue of the provision of the head loading actuator with means capable of rendering the motion conversion constant variable for effecting conversion of a motion from a linear motion of the solenoid first into a rotary motion and then into a linear motion again, such as the grooves formed at the rotary disc and the inner frame of the solenoid and the ball fitted in the grooves, the head loading system according to the invention can achieve the following effects: (i) A short stroke of the solenoid can be converted into a long stroke of the hook of the head support mechanism. (ii) The solenoid has a low electric power consumption level because head loading can be achieved with a short stroke of the solenoid. (iii) The fact that the solenoid has a low electric power consumption level leads to a reduction in the amount of heat generated by the solenoid, thereby eliminating the risks of the recording medium expanding and contracting due to a change in temperature in the apparatus. (iv) The magnetic heads can be made to move slowly toward the magnetic disc, thereby enabling damage that might otherwise be caused to the magnetic heads and magnetic disc by their collision to be eliminated. (v) The vertical dimension of the magnetic disc apparatus with respect to the surfaces of the recording medium can be reduced, because the solenoid is arranged horizontally with respect to the surfaces of the recording medium and head loading is effected by converting a linear motion of the solenoid into a rotary motion.
A head loading system including a head support mechanism supporting heads for at least reproducing information in juxtaposed relation to a recording medium, and a loading actuator driving the head support mechanism to move the heads toward and away from the recording medium. The loading actuator include motion converting arrangement for converting a linear motion of a solenoid into a rotary motion which is capable of increasing the amount of motion when the linear motion is converted into the rotary motion, thereby enabling the loading actuator to drive the heads with a small amount of linear motion. The motion converting arrangement includes a rotary member connected to a plunger of the solenoid and formed with grooves, a frame juxtaposed against the rotary member and formed with grooves and a bearing fitted between the grooves. The linear motion of the plunger is converted into a rotary motion of the rotary member by the action of the bearing performed in cooperation with the grooves.
Summarize the key points of the given document.
[ "BACKGROUND OF THE INVENTION This invention relates to head loading systems, and more particularly, to a head loading system of a magnetic disc apparatus or flexible disc apparatus, capable of moving toward and away from an information recording medium at least one magnetic head for at least reproducing information recorded on such information recording medium.", "Generally a magnetic disc apparatus or flexible disc apparatus comprises a head loading system for moving at least one magnetic head serving as an information reproducing head toward and away from a magnetic disc functioning as a recording medium for recording information therein.", "The head loading system comprises a magnetic head support mechanism for supporting the magnetic head in juxtaposed relation to one surface of the magnetic disc, and a head loading actuator for driving the magnetic head support mechanism to move the magnetic head toward and away from the surface of the magnetic disc.", "A magnetic head support mechanism of a magnetic head loading system of the prior art will be described by referring to FIGS. 1(a) to 2(b).", "The magnetic head support mechanism of the head loading system shown in FIGS. 1(a) and 1(b) comprises a gimbaled spring 4 for resiliently supporting a magnetic head 1a jaxtaposed against a top surface of a magnetic disc 6, a swing arm 3a for supporting the gimbaled spring 4 for vertical movement and supporting a hook 5 at one end portion and a downwardly projecting cam 7a at the other end portion, a swing arm 3b mounting at one end portion a magnetic head 1b in juxtaposed relation to a bottom surface of the magnetic disc 6 and having at the other end portion an upwardly extending cam 7b which is brought into engagement with the cam 7a, a support portion 50 for supporting the swing arms 3a and 3b through support springs 2, respectively, and preloading springs 8a and 8b extending from the support portion 50 to urge the swing arms 3a and 3b respectively to move in a direction in which they are closed.", "The numeral 9 designates a bail for moving the hook 5 vertically which constitute a part of the magnetic head loading actuator subsequently to be described.", "When the magnetic heads 1a and 1b are respectively located close to the top and bottom surfaces of the magnetic disc 6, the magnetic head support mechanism is located such that, as shown in FIGS. 1(a) and 1(b), the bail 9 has its forward end 9a spaced apart from the hook 5 because it is located in a lower position.", "As the swing arms 3a and 3b are pressed by the preloading springs 8a and 8b respectively, the magnetic heads 1a and 1b are moved to positions in which they are close to the top and bottom surfaces of the magnetic disc 6 respectively.", "In the head loading system of the aforesaid construction, the head loading actuator is operative to cause the forward end 9a of the bail 9 to lift the hook 5 to thereby cause the magnetic head 1a supported by the swing arm 3a through the gimbaled spring 4 to move away from the top surface of the magnetic disc 6, as shown in FIGS. 2(a) and 2(b).", "As the cam 7a moves leftwardly to press the cam 7b of the arm 3b to move it leftwardly in the figure in the process of the movement of the swing arm 3a in the clockwise direction, the swing arm 3b moves in the counterclockwise direction to move the magnetic head 1b supported by the arm 3b away from the magnetic disc 6.", "Upward movement of the bail 9 causes the parts in positions shown in FIG. 1(a) to shift to positions shown in FIG. 2(a).", "The operation characteristic of the bail 9 is very important because it would exert influences on (1) the speed of response of the head loading system to an external signal and (2) the damage which the magnetic disc and the magnetic heads might suffer when the latter strike the former.", "Particularly in recent years, the head loading actuator of a head loading system is required to have the following functions: (1) To respond quickly to an external signal and move the magnetic heads near to or into intimate contact with the magnetic disc in a very short period of time;", "(2) To avoid damage which the magnetic disc might suffer when the magnetic heads strike same by causing the latter to come into contact with the former gently;", "and (3) To perform the aforesaid operations with minimized energy.", "To cope with this situation, head loading systems of the prior art use a head loading actuator shown in FIG. 3. The head loading actuator shown in the figure comprises a push-pull solenoid 12 including a plunger 13, a coil 14 and a fixed pole 16, the bail 9 having one end adapted to come into engagement with the hook 5, and a return spring 11.", "The bail 9 has a central portion pivotally connected to the plunger 13 of the solenoid 12 and is adapted to come into engagement at the forward end 9a with the hook 5 while it is pullsed at its rear end by the return spring 11 to be pivoted at a pin 10.", "As an energizing current is passed to the coil 14, the solenoid 12 is energized and pulls the plunger 13 downwardly against the biasing force of the return spring.", "This causes the bail 9, pivotally connected to the plunger 13, to move in the clockwise direction about the pin 10 to move downwardly the hook 5 in engagement with the forward end 9a of the bail 9.", "Upon interruption of the supply of the energizing current to the coil 14, the bail 9 is moved in the counterclockwise direction by the biasing force of the return spring 11 about the pin 10 to move the hook 5 upwardly in the figure.", "By these operations, the head loading actuator moves vertically up and down the hook 5 of the magnetic head support so as to thereby move the magnetic heads toward and away from the magnetic disc.", "FIG. 4 shows the relation between the stroke and the attracting force of the solenoid 12 that can be established when the energizing current passed to the coil 14 is constant.", "In FIG. 4 the figure, it will be seen that in the process of movement of the forward end of the plunger 13 from an upper-most position (starting point 15a) of a stroke of 3 mm to a lowermost position (terminating point 15b) of a stroke of 0, the attracting force increases rapidly non-linearly from about 0.3 kg to 2.5 kg as indicated by an arrow C. The phenomenon that the attracting force increases with a reduction in stroke would be accounted for by the fact that, as the plunger 13 is attracted by the magnetic force and moves downwardly as shown in FIG. 3, the gap δ decreases and the magnetic flux density in the gap δ increases while the area spacing the plunger 13 away from the coil 12 increases.", "FIG. 5 shows the stroke/load characteristic of the head loading system in which the stroke represents an overall resilience of the system including the biasing force of the return spring 11 of the head loading actuator and the biasing forces of the preloading springs 8a and 8b of the head support mechanism.", "As the stroke decreases from a condition (starting point 15c) in which the forward end 9a of the bail 9 is in engagement with the hook 5, the load increases little by little until a point D is reached at which the magnetic heads are brought into contact with the surfaces of the magnetic disc and the bail 9 is released from engagement with the hook 5 when the load decreases once, but thereafter the load increases little by little as balance is restored between the load and the force of restitution of the return spring 11 until a terminating point 15d is reached.", "FIG. 6 shows the characteristic of FIG. 4 combined with the characteristic of FIG. 5. As shown in FIG. 6, it is necessary that an attracting force curve 100 of the solenoid 12 be higher at all times than a load curve 200 to allow the magnetic heads to move away from the magnetic disc, and the solenoid 12 would be inoperative if the attracting force is low as indicated by an attracting force curve 101.", "Attention is directed to FIGS. 4-6 in which the attracting force shown is obtained by continuously passing an energizing current of a constant value to the coil 12.", "In actual practice, the attracting force would show variations in a transition state in passing an energizing current of a constant value to the coil of an actual apparatus.", "The variations occurring in the attracting force in the transient state are as follows: (a) Assuming the magnetic field in the gap δ between the plunger 13 of the push-pull solenoid 12 and the fixed pole 16 is H(AT/m), and the magnetic flux density and the area thereof is B(WB/m 3 ) and A(m 2 ) respectively.", "Then, the attracting force F (kg) can be expressed by the following equation: ##EQU1## Assuming the magnetic permeability is μo, then the magnetic flux density B can be expressed by the following equation: B=μo.", "H (2) Thus, equation (1) can be rewritten as equation (3) as follows: ##EQU2## Assuming the constant is determined by the construction of the solenoid 12, and number of turns of the coil 14 and the energizing current are K, N and I, respectively, then the magnetic field H can be expressed by the following equation: H=K.N.I (4) From equations (3) and (4), the attracting force F can be expressed by the following equation: ##EQU3## Thus, when the constant determined by the construction of the solenoid 12 and the number of turns of the coil 14 is denoted by A o , it will be seen that the attracting force of the plunger of the solenoid of the predetermined shape is proportional to the square of the energizing current I as shown by the following equation: F=A.", "sub.o.I.sup[.", "].2 ( 6) where ##EQU4## (b) However, when the inductance and the internal resistance of the coil 14 are denoted by L and R, respectively, and a step voltage E o is impressed thereon, the energizing current will rise with an inclination of L/R with time and draw near E o /R, as shown in the following equation and FIGS. 7(a) and 7(b): ##EQU5## (c) Thus, as can be clearly seen in equations (6) and (7), a change with time of the attracting force in an actual apparatus has a characteristic such that the attracting force suddenly increases as indicated by an attracting force curve 110 shown in FIG. 8 as well as the following equation (8): ##EQU6## The stroke/attracting force characteristic shown in FIG. 8 indicates that since the attracting force 110 rises suddenly the plunger 13 has a very high acceleration when the stroke is 0.", "Because of this, there are great possibilities that the magnetic heads 1a and 1b would be forced, by the very high acceleration, to strike the magnetic disc 6 to cause damage to both the magnetic disc 6 and the magnetic heads 1a and 1b, since in an apparatus of the prior art, the hook 5 in engagement with the forward end 9a of the bail 9 would have its movement greatly accelerated.", "Moreover, the head loading system of the prior art has the problems in that a stopper 17 strikes a top surface of the solenoid 12 with a high force and produces a large noise, and that the solenoid 12 has a high consumption of electric power because it is necessary to place a string point 15e shown in FIG. 8 in a relatively high position.", "Additionally, the solenoid is located perpendicular to the planes of surfaces of the magnetic disc in the head loading system of the prior art, making it necessary for the apparatus to have, in addition to the vertical dimension of the solenoid, a vertical dimension that would enable the bail 9 and hook to move vertically upwardly away from the upper end of the solenoid.", "Thus, it has been impossible to reduce the vertical dimension of the head loading system, and consequently difficulties have been experienced in obtaining a magnetic disc apparatus of small thickness.", "A head loading actuator similar to the one shown in FIG. 3 is disclosed in Japanese Patent Application Laid-Open No. 58311/76 corresponding to U.S. Ser.", "No. 510,471, now U.S. Pat. No. 3,973,274 for example.", "In order to obviate the problems raised by the head loading actuator of the head loading system of the prior art of the aforesaid construction, attempts have been made by us to adopt the following measures: (i) The head loading actuator would have a solenoid which would, as shown in FIG. 9, be constructed such that the plunger 13 would have a lower end projecting downwardly in the form of a cone and the fixed pole 16 would have a shape complementary with the aforesaid shape of the lower end of the plunger 13, to thereby reduce as much as possible a sudden change in the attracting force by minimizing a sudden change in the magnetic flux density and the opposed surfaces of the plunger 13 and the coil 14.", "(ii) The head loading actuator would have a construction such that the point of connection between the bail 9 and the plunger 13 would be moved from the position shown in FIG. 3 to a position closer to the pin 10 serving as the pivot for the bail 9, to minimize the influences which might be exerted by a sudden change in the attracting force by decreasing the stroke of the plunger 13.", "(iii) The head loading actuator would have a construction such that the push-pull solenoid 12 would have an electrical damping function or a hydraulic damping function.", "However, it has been ascertained that some disadvantages are associated with various constructions of the head loading actuator described hereinabove.", "The solenoid construction described in paragraph (i) has proved, upon experiments, to have no marked improvement in operation characteristic.", "The head loading actuator described in paragraph (ii) could achieve no excellent effects because the compactness of the apparatus makes it impossible to increase the lever ratio l 0 /l 1 (FIG.", "3) of the bail 9.", "In the head loading actuator provided with a damper as described in paragraph (iii), the reliability of the apparatus as a whole would be lowered due to obturation of the damper and the short service life thereof, thereby making the apparatus of no practical value.", "Thus, it has been ascertained that no satisfactory operation characteristic can be obtained even if some improvements were provided in a head loading system of the prior art wherein the plunger and the bail are directly connected together.", "SUMMARY OF THE INVENTION This invention has been developed for the purpose of obviating the aforesaid disadvantages of the prior art.", "Accordingly an object of the invention is to provide a head loading system capable of moving the magnetic heads at high speed and yet bringing them into contact with a recording medium lightly with a soft tough.", "Another object is to provide a head loading system capable of operating its head loading actuator with a minimum of consumption of electric power to thereby save energy.", "A further object is to provide a head loading system enabling an information reproducing apparatus to have a small overall thickness.", "According to the invention, there is provided a head loading system comprising a head support mechanism for supporting magnetic heads in juxtaposed relation to surfaces of a recording medium, and a head loading actuator for driving the head support mechanism, the head loading actuator comprising a solenoid including a plunger and located horizontally with respect to the surfaces of the recording medium, and motion converting means connected to the plunger capable of converting a linear motion of the plunger caused by the solenoid into a rotary motion and also capable of changing the motion conversion constant.", "The motion converting means of the head loading system according to the invention may comprise a motion converting portion connected to a shaft of the solenoid, rotary disc formed on a surface thereof juxtaposed against the solenoid a plurality of grooves each having a varying depth, an inner frame of the solenoid formed in positions corresponding with the grooves of the rotary disc with a plurality of grooves each having a varying depth, and a ball fitted in the grooves of the rotary disc and the grooves of the inner frame of the solenoid.", "BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(a) and 1(b) are respectively a front view and a side view of a magnetic head support mechanism of a magnetic head loading system of a prior art with the magnetic heads being moved toward the magnetic disc;", "FIGS. 2(a) and 2(b) are respectively a front view and a side view of a magnetic head support mechanism of a magnetic head loading system of the prior art with the magnetic heads moving away from the magentic disc;", "FIG. 3 is a sectional view of ahead loading actuator of a magnetic head loading system of the prior art;", "FIG. 4 is a digrammatic representation of the attracting force/stroke characteristic of the head loading actuator shown in FIG. 3;", "FIG. 5 is a diagrammatic representation of the load/stroke characteristic of the head loading actuator shown in FIG. 3;", "FIG. 6 is a diagrammatic representation of the attracting force and the load in relation to the stroke of the head loading acturator shown in FIG. 3;", "FIG. 7(a) and 7(b) are diagrammatic representations of the relationship between the voltage impressed on the head loading actuator shown in FIG. 3 and the electric current;", "FIG. 8 is a diagrammatic representation of the attracting force and the load in relation to the stroke of a solenoid of the prior art determined by taking the impressed voltage into consideration;", "FIG. 9 shows a solenoid that has come to the mind of the inventor;", "FIG. 10 is a prespective view of one embodiment of the head loading actuator of the magnetic head loading system in conformity with the invention;", "FIG. 11 is a side view of the head loading actuator shown in FIG. 10;", "FIG. 12 shows the rotary disc of the head loading actuator shown in FIGS. 10 and 11;", "FIG. 13 is a view in explanation of the operation of the bail and the roller of the head load actuator shown in FIGS. 10 and 11;", "FIG. 14 is a diagrammatic representation of the attracting force and the load in relation to the stroke of the solenoid of the head loading actuator according to the invention;", "FIGS. 15 and 16 show the rotary disc and the inner frame of the motion converting portion of the head loading actuator according to the invention;", "FIG. 17 shows a modification of the motion converting portion of the head loading actuator according to the invention;", "FIG. 18 is a diagrammatic representation of gap/stroke characteristic of the solenoid of the head loading actuator according to the invention;", "FIG. 19 is a view showing the relation between the energizing current to the solenoid of the head loading actuator according to the invention and the signal reproduced by the magnetic head;", "FIG. 20 is a view showing the relation between the energizing current of a solenoid of a head loading actuator of the prior art and the signal reproduced by the magnetic head;", "and FIGS. 21 and 22 show the motion converting portion of the head loading actuator according to the invention for converting a linear motion of the solenoid into a rotary motion of the rotary disc.", "DETAILED DESCRIPTION FIG. 10 is a perspective view of the head loading actuator of the head loading system comprising a preferred embodiment of the invention.", "As shown, the head loading actuator comprises a bail 90 pivotable about the pin 10 which includes forward end portion 90a adapted to engage the hook 5 of the head support mechanism, a push-pull solneoid 125 including a plunger 130 which produces a linear motion for moving the plunger 130 in a straight line, and motion converting means for converting the linear motion of the plunger 130 into a rotary motion to move the forward end portion 90a of the bail 90 up and down.", "The motion converting means comprises a rotary member 18 for converting the linear motion of the plunger 130 into the rotary motion, and a pin 22 and a roller 23 for transmitting the rotary motion of the rotary member 18 to the bail 90, and is operative to move the forward end portion 90a of the bail 90 substantially vertically.", "FIG. 11 shows one side of the head loading actuator shown in FIG. 10.", "The push-pull solenoid 125 comprises a fixed pole 160, a coil 140, the plunger 130, a guide shaft 135 mounted for rotation in a center hole of the fixed pole 160 for supporting the plunger 130, a coil spring 21 mounted between one end of the guide shaft 135 and a solenoid outer frame 136 for biasing the guide shaft 135 in a predetermined direction, and a frame 137 enclosing the coil 140 and formed at its front surface with guide grooves 19a subsequently to be described.", "The rotary member 18 constituting a part of the motion converting means is mounted on the front surface of the plunger 130 to cooperate therewith and formed, at one portion of an inner surface 138, with grooves 19b of a shape subsequently to be described.", "The rotary member 18 has projecting form its outer surface the pin 22 having the roller 23 rotatably mounted at its forward end.", "The roller 23 is fitted in a bail groove 24 formed in a lower portion of the bail 90 for moving the bail 90 up and down as the rotary member 18 rotates.", "A bearing 20 is mounted between the grooves 19b of the rotary member 18 and the guide grooves 19a of the frame 137.", "Upon the plunger 130 being attracted to the pole 160 following energization of solenoid 125, the bearing 20 moves along the grooves 19a and 19b in a manner to allow the plunger 130 to move rightwardly.", "Movement of the bearing 20 causes the rotary member 18 and the plunger 130 to rotate, as subsequently to be described.", "FIG. 12 is a view showing the rotary member 18 as viewed from the direction of the inner surface 138.", "In this embodiment, the rotary member 18 is in the form of a disc and formed along its circumference with the three grooves 19b each of which is constructed such that its depth successively increases in going from one end of each groove toward the other end thereof as viewed from the side of the member 18.", "FIG. 13 which shows the bail 90, as viewed in the direction of an arrow D in FIG. 10, is a view in explanation of the relationship between the movement of the roller 24 and the pivotal movement of the bail 90 about the pin 10 occasioned by the rotation of the rotary member 18 of the head loading actuator of the aforesaid construction.", "In FIG. 13, the roller 23 extending from the rotary member 18 is fitted in the bail groove 24 formed at the lower end of the bail 90.", "Thus as the roller 23 moves with the rotation of the rotary member 18, the bail 90 moves pivotally about the pin 10.", "At this time, the engaging portion 90a of the bail 90 would move in rotary motion, strictly speaking.", "However, it is spaced apart from the pin 10 serving as the pivot in this case by a distance l and has a very small stroke S. Thus, when the angle of pivotal movement of the bail 90 is denoted by θ, the forward end portion 90a moves substantially in a linear motion.", "For example, let the stroke of the forward end of the bail 90 necessary to accomplish the desired end, the distance from the center of the pin 10 to the forward end of the bail 90, the distance from the center of the pin 10 to the rolling center of the roller 23 in the bail groove 24, the angle of pivotal movement of the bail 90, the distance from the center of the pin 10 to the center of rotation of the rotary disc 18, the angle formed by a line parallel to the X axis of the Axes X and Y crossing perpendicular to each other at the pin 10 and a line extending through the center of the rotary disc 18 and the center of the pin 22, located at its home position the angle through which the rotary disc 18 further rotates from the aforesaid angle formed by the X axis with the centers of the rotary disc 18 and the pin 22, and the distance between the center of the rotary disc 18 and the center of the pin 22 be denoted by S, l, R, θ, D, α o , α , and γ, respectively.", "Then the angle of pivotal movement of the bail 90 and the lever ratio β can be expressed by the following equations: θ=S/l (9) β=l/R (10) Furthermore, let the linear/rotary motion conversion constant decided by the angle of the grooves be denoted by a o .", "Then the angle of rotation of the rotary disc 18 and the gap δ of the solenoid 125 can be expressed by the following equation: α=a.", "sub.o.δ (11) Thus, the relation between the gap δ of the solenoid 125 and the stroke S can be expressed by the following equation (12): ##EQU7## Since the lever ratio β, the distance γ and the constant a o are decided by the structural dimensions, equation (12) shows that the necessary stroke S of the engaging portion 90a of the bail 90 and the gap δ of the solenoid 125 are proportional to each other using as a constant one of different types of variable values.", "For example, the stroke S'", "and the gap δ'", "of the head loading drive section shown in FIG. 3 are proportional to each other only using the lever ratio β'", "as a constant as shown in the following equation (13): S'=β'.", "δ'", "(13) In view of the limitations placed on the dimensions of the apparatus, it has been impossible to impart a sufficiently large value to the lever ratio β'", "and, consequently, the head loading drive section of the prior art has hitherto been unable to give a sufficiently large value to the stroke S'.", "The lever ratio β'", "is required to be based on a high dimensional accuracy because the distance covered by the movement of the plunger of the solenoid would be increased only by the lever ratio β'.", "However, in the embodiment of the invention described hereinabove, the head loading actuator is able, as shown in FIG. 12, to impart a large value to the stroke S of the engaging portion 90a of the bail 90 even if the gap δ is small or the amount of movement of the plunger 130 is small, by increasing the constant a o which is decided by the angle of the grooves 19a and 19b, in the even that the distance γ has a small value due to the need to reduce the thickness of the apparatus.", "Considering a case in which the stroke S=S'=3 mm.", "In this case, the value of the gap δ is required to be 1.5 mm in the prior art because the lever ratio β'=2.", "In the embodiment described hereinabove, it will be seen that the gap δ can be reduced to about 1/3 the value obtained in the prior art as indicated by the following equation, with the lever ratio β'=1.2, the distance γ=13.5 and the constant a o =0.37 rad/mm: ##EQU8## Thus, it will be appreciated that the push-pull solenoid 125 is able to operate in a position in which the attracting force undergoes little change with respect to the stroke.", "Moreover, since the head loading actuator according to the invention is capable of operation in a positoin in which the attracting force of the push-pull solenoid 125 undergoes little change with respect to the stroke S of the plunger, it is possible to reduce the operation velocity of the bail 9 by taking the following measures: According to Faraday's law, a voltage e generated at opposite ends of a winding is related to a change in time of a magnetic field H and the number of turns.", "The relation can be expressed by the following equation (14): ##EQU9## By modifying equation (14) and performing bilateral integration, the following equation (15) can be obtained: ##EQU10## Here, as shown by equation (3), the attracting force F of the push-pull solenoid 125 can be expressed by the following equation (16) by substituting equation (15) into equation (13): ##EQU11## Equation (16) indicates the following: (i) The attracting force increases with time integration of the impressed voltage.", "Thus, stepwise impression of a voltage would causes the attracting force to gradually increases with time as shown in FIG. 7a.", "(ii) The change with time in attracting force, particularly its rise characteristic, could be varied by the number of turns N of the winding, thereby enabling rise to be achieved smoothly.", "This would make it possible to design a magnetic head loading system in which the attracting force does not show an excessively large change with respect to a change in the gap δ of the push-pull solenoid or the stroke of the bail 90.", "FIG. 14 is a diagrammatic representation of the attracting force/load characteristic in relation to the stroke characteristic of the embodiment shown in FIG. 10.", "It will be seen that an attracting force curve 300 and a load curve 200 at the forward end of the bail in relation to the stroke characteristic indicate a marked improvement as compared with those shown in FIG. 6. Operation of the head loading actuator of the magnetic head loading system shown in FIG. 10 of the aforesaid construction will be described.", "In the head loading actuator shown in FIGS. 10 and 11, the coil spring 21 urges the guide shaft 135 to move leftwardly in the figure by its force of restitution when no energizing current is passed to the solenoid 125.", "The coil spring 21 is operative to unload the magnetic heads by pressing the plunger 130 when the energizing current is cut off.", "In this condition, a space x 1 is formed between the frame 137 of the plunger 125 and the inner surface 138 and the bearing 20 is positioned in the smaller depth portions of the grooves 19a and 19b.", "FIG. 15 shows, in a fragmentary sectional view, the rotary member 18 and the frame 137 as viewed longitudinally of the grooves 19a and 19b in the aforesaid condition.", "It will be clearly seen that the ball 20 is positioned in the small depth portions of the grooves 19a and 19b.", "At this time, the rotary disc 18 causes by its rotation the pin 22 to be disposed in a relatively high position as shown in FIG. 21.", "Thus, the roller 23 connected to the pin 22 pushes the forward end portion 90a of the bail 90 upwardly as shown in a broken line in FIG. 13, to thereby push upwardly the hook 5 of the magnetic head support mechanism.", "In this condition, the magnetic heads 1a and 1b are away from the magnetic disc 6 as shown in FIGS. 2(a) and 2(b).", "When it is desired to move the magnetic heads toward the magnetic disc, a current is passed to the solenoid 125 of the head loading actuator to attract the plunger 130 supported by the guide shaft 135 to the fixed pole 160.", "The attracting force of the solenoid 125 tends to move the bearing 20 to large depth portions of the grooves 19a and 19b.", "This makes the rotary member 18 move in the direction of an arrow E 1 shown in FIG. 21 as the bearing 20 rotates, so that the rotary member 18 rotates in the direction of an arrow E 2 as the bearing 20 moves.", "In this fashion, the motion converting mechanism of the embodiment first converts a linear motion of the plunger 130 of the solenoid 125 into a rotary motion of the rotary disc 18.", "When the plunger 130 reaches its terminating position of its movement caused by the attracting force of the plunger 125, the bearing 20 is located in the maximum depth portions of the grooves 19a and 19b as shown in FIGS. 22 and 16.", "With the bearing 20 in this position, the rotary member 18 and the frame 137 are disposed close to each other with a spacing of x 2 therebetween.", "At this time, the pin is moved by the rotation of the rotary member 18 to its lowermost position, and causes the engaging portion 90a of the bail 90 to move downwardly to a position in which it is released from engagement with the hook 5, as shown in solid lines in FIG. 13.", "The movement of the forward end portion 90a of the bail 90 when the magnetic heads 1a and 1b are moved toward the magnetic disc 6 will be described.", "FIG. 18 shows the relation between the stroke of the forward end portion 90a and the gap δ of the solenoid 125.", "As shown in the figure, the stroke of the forward end portion 90a of the bail 90 of the embodiment can vary linearly as indicated by a characteristic line 500 shown in a broken line from a starting point 15e at which the gap δ of the solenoid 125 is 0.5 mm to a terminating point 15d at which the gap δ is 0 mm.", "Thus, the head loading actuator of the embodiment enables the stroke of the forward end portion 90a of the bail 90 to be increased to 3 mm by using the stroke of 0.5 mm of the solenoid 125.", "This is supported by equation (14).", "In the head loading actuator according to the invention, the loading characteristic can be controlled by the configuration of the grooves 19a and 19b.", "For example, by imparting a smoothly curved surface to each of the grooves 19a and 19b as shown in FIG. 17, it is possible to cause the stroke of the forward end portion 90a of the bail 90 to vary in a curve as shown by a line 400 in FIG. 18.", "When this is the case, the head loading actuator can operate such that the movement of the magnetic heads can be slowed down as they draw near the magnetic head.", "FIG. 19 shows the results of experiments conducted on the change-with-time characteristic of an energizing current 600 of the solenoid 125 of the head loading actuator of the embodiment and a reproducing signal 700 of the magnetic heads detected in the loading process, and FIG. 20 shows the change-with-time characteristic of an energizing current 800 and a reproducing signal 900 of a head loading actuator of the prior art.", "It will be seen in FIGS. 19 and 20 that the head loading actuator according to the invention is capable of operation with the energizing current 600 of 110 mA which is about one half that of the energizing current 800 of the prior art shown in FIG. 20, and that the energizing current 600 and the reproducing signal 700 of the magnetic heads has a characteristic such that they successively increase with time, indicating that the magnetic heads can move toward the magnetic disc slowly.", "The fact that the energizing current required by the head loading actuator according to the invention is small offers the advantages that the head loading actuator has a low electric power consumption level and generates little heat.", "The fact that the magnetic heads moves slowly toward the magnetic disc offers the advantages that damage that might otherwise be caused to the magnetic heads and magnetic disc as the former suddenly strike the latter with a high force and that the head loading system having the solenoid arranged horizontally can have its thickness reduced.", "By virtue of the provision of the head loading actuator with means capable of rendering the motion conversion constant variable for effecting conversion of a motion from a linear motion of the solenoid first into a rotary motion and then into a linear motion again, such as the grooves formed at the rotary disc and the inner frame of the solenoid and the ball fitted in the grooves, the head loading system according to the invention can achieve the following effects: (i) A short stroke of the solenoid can be converted into a long stroke of the hook of the head support mechanism.", "(ii) The solenoid has a low electric power consumption level because head loading can be achieved with a short stroke of the solenoid.", "(iii) The fact that the solenoid has a low electric power consumption level leads to a reduction in the amount of heat generated by the solenoid, thereby eliminating the risks of the recording medium expanding and contracting due to a change in temperature in the apparatus.", "(iv) The magnetic heads can be made to move slowly toward the magnetic disc, thereby enabling damage that might otherwise be caused to the magnetic heads and magnetic disc by their collision to be eliminated.", "(v) The vertical dimension of the magnetic disc apparatus with respect to the surfaces of the recording medium can be reduced, because the solenoid is arranged horizontally with respect to the surfaces of the recording medium and head loading is effected by converting a linear motion of the solenoid into a rotary motion." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to peripherals comprising a serial port for connecting to a master device, like a computer or a hub, via a serial link. 2. Description of the Related Art The present invention more particularly relates to peripherals comprising a serial port of the USB type (Universal Serial Bus), for connecting to a master device. A serial port of the USB type comprises four connection terminals, that is two differential data transmission terminals, and two positive and negative power supply terminals able to supply continuous current to the peripheral. Usually, a master device comprises means for detecting the connection and disconnection of a peripheral device of the USB type. This detection function does not exist on the side of a peripheral of the USB type. However, a peripheral can be connected to a master device with one and/or the other transmission links faulty, so that the peripheral is powered by the USB link but cannot communicate with the master device. If it is a secured device, like microprocessor cards memorizing secret information, fraudsters can try to discover these secret information by powering on the card and taking measures on the data transmission terminals. It is therefore desirable to be able to adapt the operating mode of the peripheral depending on whether it is connected to a master device, and particularly to determine whether the peripheral can securely communicate through the serial link. The detection by a peripheral of a master device connected to the peripheral via a USB link sometimes raises several issues. First, the USB standard 2.0 provides three data transmission speeds, that is a Low Speed of 1.2 Mb/s, a Full Speed of 12 Mb/s and a High Speed of 480 Mb/s. The master device must be able to detect the transmission speed used by the peripheral. However, according to the USB standard, the selection of one of these transmission speeds is performed by the master device according to some features of the serial port of the peripheral. In particular, a peripheral of the USB type comprises a pull-up resistor connectable to one or the other data transmission terminal of the USB port, according to the transmission speed compatible with the peripheral. This speed is determined by the master device by detecting whether one or the other positive or negative data transmission terminal is connected to this resistor. If this resistor is connected to the positive transmission terminal, the USB port of the peripheral operates at full speed. If this resistor is connected to the negative transmission terminal, the USB port of the peripheral operates at low speed. At last, if this resistor is not connected to any transmission terminals, the peripheral operates at high speed. Next, the USB standard imposes voltage levels on data transmission terminals. Particularly, the voltage must not simultaneously exceed 0.8 Volt on both data transmission terminals. BRIEF SUMMARY OF THE INVENTION One embodiment of the present invention overcomes these problems and enables a peripheral to detect the presence of a master device to which it is connected through a serial link. One embodiment of the invention is a device comprising a serial port for connecting itself as a slave to a master device via a serial link. According to one embodiment of the invention, the device comprises a detection circuit for detecting the presence of an impedance of a master device, linked to a terminal of the serial port. According to one embodiment, the impedance detected by the detection circuit is a pull-down resistor. According to one embodiment, the impedance detected by the detection circuit is a resistor with a value comprised within a range of values. According to one embodiment, the detection circuit comprises a bias stage for generating a measure voltage on the terminal of the serial port, and a detection stage comprising at least one comparator for comparing the measure voltage to a reference voltage. According to one embodiment, the detection stage comprises two comparators for comparing the measure voltage to a high reference voltage and a low reference voltage, and means for generating a detection signal indicating whether the measure voltage is comprised between the high and low reference voltages. According to one embodiment, the detection circuit comprises a first detection stage of a first pull-down resistor of a master device, linked to a first terminal of the serial port, and a second detection stage of a second pull-down resistor of the master device, linked to a second terminal of the serial port. According to one embodiment, the detection circuit comprises a bias stage for generating a first measure voltage on the first terminal of the serial port, and a second measure voltage on the second terminal of the serial port, each detection stage comprising at least one comparator for comparing the measure voltage to a reference voltage. According to one embodiment, each measure voltage is lower than 0.8 Volt, even if there is not any pull-down resistors of a master device connected to the terminals of the serial port. According to one embodiment, the detection circuit comprises means for generating a detection signal indicating whether the two detection stages detect the presence of a pull-down resistor with a value comprised within a range of values. According to one embodiment, each detection stage comprises two comparators for comparing the measure voltage to a high reference voltage and a low reference voltage, and means for generating a detection signal indicating whether the measure voltage is comprised between the high and low reference voltages. According to one embodiment, the first and second terminals of the serial port are dedicated to data transmission in differential form. According to one embodiment, the detection circuit is powered through third and fourth terminals of the serial port. According to one embodiment, the detection circuit is deactivated after detecting a master device, and before establishing a communication through the serial link. According to one embodiment, the serial port is of the Universal Serial Bus type. According to one embodiment, the device is an integrated circuit. According to another embodiment, a method for establishing data communication between a master device coupled to a slave device via a serial link, where the slave device has a serial port and the serial port has data terminals, includes determining whether an impedance of the master device is between a low impedance value and a high impedance value, and establishing data communication if the impedance of the master device is between the low impedance and high impedance values. According to a further embodiment of the invention, a system for establishing data communication over a serial link connecting a master device and a slave device, where the master device has a means for detecting data transmission speed and the slave device has a serial port having a data terminal, includes a means for disabling the data transmission speed detection means, a means for determining whether an impedance of the master device is between a low impedance value and a high impedance value, a means for enabling the data transmission speed detection means if the impedance is between the low impedance value and the high impedance value, and a means for establishing data communication over the serial link if the impedance is between the low and high impedance values. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) These and other advantages and features of the present invention will be presented in greater detail in the following description of the invention in relation to, but not limited by the following figures: FIG. 1 shows, in block form, a master device connected to a peripheral through a USB linked at full speed, according to an embodiment of the invention; FIG. 2 shows, in block form, a master device connected to a peripheral through a USB link at low speed, according to an embodiment of the invention; FIG. 3 shows, in block form, an interface circuit of a USB port of a peripheral equipped with a master device detection circuit according to an embodiment of the invention; FIG. 4 shows an embodiment of a detection circuit according to the invention; and FIG. 5 is a diagram of a startup procedure executed by a peripheral equipped with a detection circuit according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 show a master device H constituted by a computer or a hub, connected through a serial link SL of the USB type to a slave device or peripheral P. The master device H comprises an interface circuit USBT1 connected to a serial port comprising two positive and negative data transmission terminals D+, D−. Each terminal D+ and D− is connected to a line of differential data transmission of the serial link SL. The master device comprises two pull-down resistors Rpd. Each resistor respectively links a data terminal D+, D− of the serial port to the ground. The peripheral P also comprises an interface circuit USBT2 connected to a serial port comprising two terminals D+, D− connected to the data transmission lines of the serial link SL. FIG. 1 illustrates the case where the transmission between the master device H and the peripheral P is performed at full speed. In that case, the positive data transmission terminal D+ of the peripheral P is linked to the supply voltage Vcc supplied by the link USB by means of a pull-up resistor Rpu mounted in series with a switch 11 . FIG. 2 illustrates the case where the link USB SL between the master device H and the peripheral P is at low speed. In that case, the pull-up resistor Rpu connected to the power supply Vcc is linked to the negative data transmission terminal D− via a switch I 2 . FIG. 3 shows the interface circuit USBT2 of the peripheral P. FIG. 3 shows the four connection terminals of the USB serial port of the peripheral. These four terminals comprise two positive and negative continuous power supply terminals VBUS, GND at about 3.3 Volts, and the two differential data transmission terminals D+, D− described hereinbefore and shown in FIGS. 1 and 2 . The circuit USBT 2 comprises send buffer memories DPT, DMT, single-ended receivers DPR, DMR, and a differential receiver DIFR. The positive data transmission terminal D+ is connected to the output of the send buffer memory DPT, to the input of the receiver DPR, and to a positive input of the differential receiver DIFR. The negative data transmission terminal D− is connected to the output of the send buffer memory DMT, to the input of the receiver DMR, and to a negative input of the differential receiver DIFR. The power supply terminals VBUS and GND power a DC voltage regulator DCREG. The regulator DCREG supplies a supply voltage of 3 Volts to the receivers DPR, DIFR, DMR and to the send buffer memories DPT, DMT. The receivers DPR, DIFR, DMR respectively supply data signals DPRO, DIFO and DMRO carrying the data transmitted by the link SL. The send buffer memories DPT, DMT receive from the peripheral P data signals DPOS, DMOS to be emitted on the link SL. The interface circuit USBT2 comprises a detection circuit DCT enabling the peripheral P to detect whether it is connected to a master device H through a link of the USB type. FIG. 4 shows an embodiment of the detection circuit DCT shown in FIG. 3 . The detection circuit DCT comprises a DC voltage generator VGEN, powered by the power supply terminals VBUS, GND of the USB port. The voltage generator VGEN supplies a continuous voltage Vg+, through a resistor Rd+, to the positive data terminal D+ of the USB port of the peripheral. Likewise, the voltage generator VGEN supplies a continuous voltage Vg−, through a resistor Rd−, to the negative data terminal D− of the USB port. The voltage generator VGEN thus applies to the positive and negative data terminals measure voltages Vm+ and Vm− with resistors Rpd possibly connected by a serial link SL to the terminals D+ and D−. The voltage generator VGEN also applies a continuous voltage Vg to a group of three resistors R 1 , R 2 , R 3 mounted in series, the resistor R 1 being connected to the generator VGEN, and the resistor R 3 being connected to the ground, that is the ground terminal GND of the USB port of the peripheral P. The resistors R 1 and R 2 form a first divider bridge supplying a high reference voltage VH in their junction node. In the same way, the resistors R 2 and R 3 form a second divider bridge supplying a low reference voltage VL in their junction node. The detection circuit DCT also comprises two detection stages DST 1 , DST 2 , each comprising two comparators C 1 , C 2 , C 3 , C 4 which outputs are connected to the inputs of an AND gate AG 1 , AG 2 . The outputs ER+, ER− of the gates AG 1 , AG 2 are connected to the inputs of another AND gate AG 3 which output supplies a signal of detection ER of a master device. The terminal D+ is connected to the negative input of the comparator C 1 and to the positive input of the comparator C 2 . In addition, the high reference voltage VH is applied to the positive input of the comparator C 1 , and the low reference voltage VL is applied to the negative input of the comparator C 2 . That way, the output of the gate AG 1 is pulled up if the value of the measure voltage Vm+ applied to the terminal D+ is comprised between the low VL and high VH reference voltages, and otherwise pulled down. In the same way, the terminal D− is connected to the negative input of the comparator C 4 and to the positive input of the comparator C 3 . The high reference voltage VH is applied to the positive input of the comparator C 4 , and the low reference voltage VL is applied to the negative input of the comparator C 3 . The output of the gate AG 2 is thus pulled up if the value of the measure voltage Vm− applied to the terminal D− is comprised between the low VL and high VH reference voltages, and otherwise pulled down. The detection signal ER at the output of the detection circuit is pulled up if the following conditions are simultaneously satisfied: VL<Vm+<VH   (1) VL<Vm−<VH   (2) and otherwise pulled down. If pull-down resistors Rpd are connected to the data lines D+, D− of the serial link SL, each forms with the resistor Rd− to which it is connected, a divider bridge to divide the voltage Vg+, Vg−. The data terminal D+, D− connected to the junction node of the resistors Rdp and Rd+ (or Rdp and Rd−) thus supplies a measure voltage Vm+, Vm− depending on the value of the resistor Rpd connected to the data terminal. If the resistors Rd+, Rd−, R 1 , R 2 , R 3 are all chosen substantially equal to a predefined resistor R, and if the voltages Vg+, Vg− and Vg supplied by the generator VGEN are substantially equal, the conditions (1) and (2) are equivalent to the following conditions: ⅓ <Rpd /( Rpd+R )<⅔  (3) or: R/ 2 <Rpd< 2 R   (4) If the value of the resistor R is chosen near the one of the pull-down resistors, recommended by the USB standard, that is 15 kOhms, and if pull-down resistors Rpd are present on the USB link connected to the peripheral P, the conditions (4) are satisfied for each data terminal D+ and D−. On the other hand, these conditions are not satisfied if the data terminals D+ and D− are not connected to a USB port of a master device, that is if one and/or the other terminal D+ and/or D− of the peripheral is not connected to a pull-down resistor Rpd, or is in short-circuit with the ground. The detection circuit DCT which has just been described thus makes it possible to detect the presence of pull-down resistors Rpd of a master device H, connected to the positive D+ and negative D− data terminals of the USB port of the peripheral. In addition, if the continuous voltages Vg+, Vg− and Vg supplied by the generator VGEN are lower than 0.8 Volts, the detection circuit which has just been described complies with the condition SE1 specified in the USB standard, which imposes that the voltages applied to the terminals D+ and D− must not exceed a voltage Vose1 equal to 0.8 Volt at the same time. FIG. 5 shows a procedure 10 for starting-up the peripheral P according to the invention. At the startup of the peripheral, the peripheral controls the opening of the switch I 1 or I 2 depending on whether the USB link of the peripheral is at full or low speed, to disconnect the pull-up resistor Rpu (step 11 ). At the following step 12 , the peripheral tests the output signal ER of the detection circuit DCT. If the output signal is pulled up, it means that pull-down resistors Rpd of a master device H are linked by the link SL to the data terminals D+, D− of the peripheral P. In that case, the peripheral closes the switch I 1 or I 2 (step 13 ), and tries to establish a communication through its USB port with the master device thus detected (step 14 ). If at step 12 the detection signal ER is pulled-down (ER=0), it means that the detection circuit DCT has not detected, on each terminal D+, D−, the presence of a pull-down resistor Rpd having a correct value (conditions (4) not satisfied). The procedure 10 then ends without the peripheral trying to establish a communication through its serial port. The detection circuit DCT can also comprise a deactivation switch 13 controlled by the peripheral P ( FIG. 4 ). This switch allows the detection circuit to be deactivated when the peripheral is live and has detected the presence of a master device H. The switch 13 is for example interposed on a supply line of the voltage generator VGEN connected to the power supply terminal VBUS of the serial port. The switch 13 is closed at the start-up of the peripheral, and opened before establishing a communication with the master device, after the detection of the latter. It will be clear to those skilled in the art that the device according to the invention is susceptible of several variations. Thus, the invention does not necessarily apply to a USB link: it more globally applies to any serial link connecting a master device to a slave device. In addition, the impedance detected is not necessarily a pull-down resistor. The detection of the impedance is not necessarily performed on a data transmission line of the serial link. It can alternately be performed on a supply line of the serial link. In the case of a differential serial link, it is not necessary to detect the presence of an impedance on each data terminal D+ and D−. Only one of these two terminals can be subjected to the detection performed by the detection circuit. In that case, the voltage generator VGEN generates one measure voltage Vm+ or Vm− only, and the detection circuit DCT comprises one detection stage DST 1 or DST 2 only. In addition, it is not necessary to compare the measure voltage Vm+, Vm− to a high reference voltage and a low reference voltage. To simply detect the presence or the lack of a resistor, comparing the measure voltage with a high reference voltage is sufficient. To detect if a terminal of the serial port is linked to the ground, comparing the measure voltage to a low reference voltage is sufficient.
A device includes a serial port for connecting as a slave to a master device through a serial link. The device further includes a detection circuit for detecting the presence of an impedance of the master device, linked to a terminal of the serial port. The device can be used with microprocessor cards comprising a USB port.
Briefly describe the main idea outlined in the provided context.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to peripherals comprising a serial port for connecting to a master device, like a computer or a hub, via a serial link.", "Description of the Related Art The present invention more particularly relates to peripherals comprising a serial port of the USB type (Universal Serial Bus), for connecting to a master device.", "A serial port of the USB type comprises four connection terminals, that is two differential data transmission terminals, and two positive and negative power supply terminals able to supply continuous current to the peripheral.", "Usually, a master device comprises means for detecting the connection and disconnection of a peripheral device of the USB type.", "This detection function does not exist on the side of a peripheral of the USB type.", "However, a peripheral can be connected to a master device with one and/or the other transmission links faulty, so that the peripheral is powered by the USB link but cannot communicate with the master device.", "If it is a secured device, like microprocessor cards memorizing secret information, fraudsters can try to discover these secret information by powering on the card and taking measures on the data transmission terminals.", "It is therefore desirable to be able to adapt the operating mode of the peripheral depending on whether it is connected to a master device, and particularly to determine whether the peripheral can securely communicate through the serial link.", "The detection by a peripheral of a master device connected to the peripheral via a USB link sometimes raises several issues.", "First, the USB standard 2.0 provides three data transmission speeds, that is a Low Speed of 1.2 Mb/s, a Full Speed of 12 Mb/s and a High Speed of 480 Mb/s.", "The master device must be able to detect the transmission speed used by the peripheral.", "However, according to the USB standard, the selection of one of these transmission speeds is performed by the master device according to some features of the serial port of the peripheral.", "In particular, a peripheral of the USB type comprises a pull-up resistor connectable to one or the other data transmission terminal of the USB port, according to the transmission speed compatible with the peripheral.", "This speed is determined by the master device by detecting whether one or the other positive or negative data transmission terminal is connected to this resistor.", "If this resistor is connected to the positive transmission terminal, the USB port of the peripheral operates at full speed.", "If this resistor is connected to the negative transmission terminal, the USB port of the peripheral operates at low speed.", "At last, if this resistor is not connected to any transmission terminals, the peripheral operates at high speed.", "Next, the USB standard imposes voltage levels on data transmission terminals.", "Particularly, the voltage must not simultaneously exceed 0.8 Volt on both data transmission terminals.", "BRIEF SUMMARY OF THE INVENTION One embodiment of the present invention overcomes these problems and enables a peripheral to detect the presence of a master device to which it is connected through a serial link.", "One embodiment of the invention is a device comprising a serial port for connecting itself as a slave to a master device via a serial link.", "According to one embodiment of the invention, the device comprises a detection circuit for detecting the presence of an impedance of a master device, linked to a terminal of the serial port.", "According to one embodiment, the impedance detected by the detection circuit is a pull-down resistor.", "According to one embodiment, the impedance detected by the detection circuit is a resistor with a value comprised within a range of values.", "According to one embodiment, the detection circuit comprises a bias stage for generating a measure voltage on the terminal of the serial port, and a detection stage comprising at least one comparator for comparing the measure voltage to a reference voltage.", "According to one embodiment, the detection stage comprises two comparators for comparing the measure voltage to a high reference voltage and a low reference voltage, and means for generating a detection signal indicating whether the measure voltage is comprised between the high and low reference voltages.", "According to one embodiment, the detection circuit comprises a first detection stage of a first pull-down resistor of a master device, linked to a first terminal of the serial port, and a second detection stage of a second pull-down resistor of the master device, linked to a second terminal of the serial port.", "According to one embodiment, the detection circuit comprises a bias stage for generating a first measure voltage on the first terminal of the serial port, and a second measure voltage on the second terminal of the serial port, each detection stage comprising at least one comparator for comparing the measure voltage to a reference voltage.", "According to one embodiment, each measure voltage is lower than 0.8 Volt, even if there is not any pull-down resistors of a master device connected to the terminals of the serial port.", "According to one embodiment, the detection circuit comprises means for generating a detection signal indicating whether the two detection stages detect the presence of a pull-down resistor with a value comprised within a range of values.", "According to one embodiment, each detection stage comprises two comparators for comparing the measure voltage to a high reference voltage and a low reference voltage, and means for generating a detection signal indicating whether the measure voltage is comprised between the high and low reference voltages.", "According to one embodiment, the first and second terminals of the serial port are dedicated to data transmission in differential form.", "According to one embodiment, the detection circuit is powered through third and fourth terminals of the serial port.", "According to one embodiment, the detection circuit is deactivated after detecting a master device, and before establishing a communication through the serial link.", "According to one embodiment, the serial port is of the Universal Serial Bus type.", "According to one embodiment, the device is an integrated circuit.", "According to another embodiment, a method for establishing data communication between a master device coupled to a slave device via a serial link, where the slave device has a serial port and the serial port has data terminals, includes determining whether an impedance of the master device is between a low impedance value and a high impedance value, and establishing data communication if the impedance of the master device is between the low impedance and high impedance values.", "According to a further embodiment of the invention, a system for establishing data communication over a serial link connecting a master device and a slave device, where the master device has a means for detecting data transmission speed and the slave device has a serial port having a data terminal, includes a means for disabling the data transmission speed detection means, a means for determining whether an impedance of the master device is between a low impedance value and a high impedance value, a means for enabling the data transmission speed detection means if the impedance is between the low impedance value and the high impedance value, and a means for establishing data communication over the serial link if the impedance is between the low and high impedance values.", "BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) These and other advantages and features of the present invention will be presented in greater detail in the following description of the invention in relation to, but not limited by the following figures: FIG. 1 shows, in block form, a master device connected to a peripheral through a USB linked at full speed, according to an embodiment of the invention;", "FIG. 2 shows, in block form, a master device connected to a peripheral through a USB link at low speed, according to an embodiment of the invention;", "FIG. 3 shows, in block form, an interface circuit of a USB port of a peripheral equipped with a master device detection circuit according to an embodiment of the invention;", "FIG. 4 shows an embodiment of a detection circuit according to the invention;", "and FIG. 5 is a diagram of a startup procedure executed by a peripheral equipped with a detection circuit according to an embodiment of the invention.", "DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 show a master device H constituted by a computer or a hub, connected through a serial link SL of the USB type to a slave device or peripheral P. The master device H comprises an interface circuit USBT1 connected to a serial port comprising two positive and negative data transmission terminals D+, D−.", "Each terminal D+ and D− is connected to a line of differential data transmission of the serial link SL.", "The master device comprises two pull-down resistors Rpd.", "Each resistor respectively links a data terminal D+, D− of the serial port to the ground.", "The peripheral P also comprises an interface circuit USBT2 connected to a serial port comprising two terminals D+, D− connected to the data transmission lines of the serial link SL.", "FIG. 1 illustrates the case where the transmission between the master device H and the peripheral P is performed at full speed.", "In that case, the positive data transmission terminal D+ of the peripheral P is linked to the supply voltage Vcc supplied by the link USB by means of a pull-up resistor Rpu mounted in series with a switch 11 .", "FIG. 2 illustrates the case where the link USB SL between the master device H and the peripheral P is at low speed.", "In that case, the pull-up resistor Rpu connected to the power supply Vcc is linked to the negative data transmission terminal D− via a switch I 2 .", "FIG. 3 shows the interface circuit USBT2 of the peripheral P. FIG. 3 shows the four connection terminals of the USB serial port of the peripheral.", "These four terminals comprise two positive and negative continuous power supply terminals VBUS, GND at about 3.3 Volts, and the two differential data transmission terminals D+, D− described hereinbefore and shown in FIGS. 1 and 2 .", "The circuit USBT 2 comprises send buffer memories DPT, DMT, single-ended receivers DPR, DMR, and a differential receiver DIFR.", "The positive data transmission terminal D+ is connected to the output of the send buffer memory DPT, to the input of the receiver DPR, and to a positive input of the differential receiver DIFR.", "The negative data transmission terminal D− is connected to the output of the send buffer memory DMT, to the input of the receiver DMR, and to a negative input of the differential receiver DIFR.", "The power supply terminals VBUS and GND power a DC voltage regulator DCREG.", "The regulator DCREG supplies a supply voltage of 3 Volts to the receivers DPR, DIFR, DMR and to the send buffer memories DPT, DMT.", "The receivers DPR, DIFR, DMR respectively supply data signals DPRO, DIFO and DMRO carrying the data transmitted by the link SL.", "The send buffer memories DPT, DMT receive from the peripheral P data signals DPOS, DMOS to be emitted on the link SL.", "The interface circuit USBT2 comprises a detection circuit DCT enabling the peripheral P to detect whether it is connected to a master device H through a link of the USB type.", "FIG. 4 shows an embodiment of the detection circuit DCT shown in FIG. 3 .", "The detection circuit DCT comprises a DC voltage generator VGEN, powered by the power supply terminals VBUS, GND of the USB port.", "The voltage generator VGEN supplies a continuous voltage Vg+, through a resistor Rd+, to the positive data terminal D+ of the USB port of the peripheral.", "Likewise, the voltage generator VGEN supplies a continuous voltage Vg−, through a resistor Rd−, to the negative data terminal D− of the USB port.", "The voltage generator VGEN thus applies to the positive and negative data terminals measure voltages Vm+ and Vm− with resistors Rpd possibly connected by a serial link SL to the terminals D+ and D−.", "The voltage generator VGEN also applies a continuous voltage Vg to a group of three resistors R 1 , R 2 , R 3 mounted in series, the resistor R 1 being connected to the generator VGEN, and the resistor R 3 being connected to the ground, that is the ground terminal GND of the USB port of the peripheral P. The resistors R 1 and R 2 form a first divider bridge supplying a high reference voltage VH in their junction node.", "In the same way, the resistors R 2 and R 3 form a second divider bridge supplying a low reference voltage VL in their junction node.", "The detection circuit DCT also comprises two detection stages DST 1 , DST 2 , each comprising two comparators C 1 , C 2 , C 3 , C 4 which outputs are connected to the inputs of an AND gate AG 1 , AG 2 .", "The outputs ER+, ER− of the gates AG 1 , AG 2 are connected to the inputs of another AND gate AG 3 which output supplies a signal of detection ER of a master device.", "The terminal D+ is connected to the negative input of the comparator C 1 and to the positive input of the comparator C 2 .", "In addition, the high reference voltage VH is applied to the positive input of the comparator C 1 , and the low reference voltage VL is applied to the negative input of the comparator C 2 .", "That way, the output of the gate AG 1 is pulled up if the value of the measure voltage Vm+ applied to the terminal D+ is comprised between the low VL and high VH reference voltages, and otherwise pulled down.", "In the same way, the terminal D− is connected to the negative input of the comparator C 4 and to the positive input of the comparator C 3 .", "The high reference voltage VH is applied to the positive input of the comparator C 4 , and the low reference voltage VL is applied to the negative input of the comparator C 3 .", "The output of the gate AG 2 is thus pulled up if the value of the measure voltage Vm− applied to the terminal D− is comprised between the low VL and high VH reference voltages, and otherwise pulled down.", "The detection signal ER at the output of the detection circuit is pulled up if the following conditions are simultaneously satisfied: VL<Vm+<VH (1) VL<Vm−<VH (2) and otherwise pulled down.", "If pull-down resistors Rpd are connected to the data lines D+, D− of the serial link SL, each forms with the resistor Rd− to which it is connected, a divider bridge to divide the voltage Vg+, Vg−.", "The data terminal D+, D− connected to the junction node of the resistors Rdp and Rd+ (or Rdp and Rd−) thus supplies a measure voltage Vm+, Vm− depending on the value of the resistor Rpd connected to the data terminal.", "If the resistors Rd+, Rd−, R 1 , R 2 , R 3 are all chosen substantially equal to a predefined resistor R, and if the voltages Vg+, Vg− and Vg supplied by the generator VGEN are substantially equal, the conditions (1) and (2) are equivalent to the following conditions: ⅓ <Rpd /( Rpd+R )<⅔ (3) or: R/ 2 <Rpd<", "2 R (4) If the value of the resistor R is chosen near the one of the pull-down resistors, recommended by the USB standard, that is 15 kOhms, and if pull-down resistors Rpd are present on the USB link connected to the peripheral P, the conditions (4) are satisfied for each data terminal D+ and D−.", "On the other hand, these conditions are not satisfied if the data terminals D+ and D− are not connected to a USB port of a master device, that is if one and/or the other terminal D+ and/or D− of the peripheral is not connected to a pull-down resistor Rpd, or is in short-circuit with the ground.", "The detection circuit DCT which has just been described thus makes it possible to detect the presence of pull-down resistors Rpd of a master device H, connected to the positive D+ and negative D− data terminals of the USB port of the peripheral.", "In addition, if the continuous voltages Vg+, Vg− and Vg supplied by the generator VGEN are lower than 0.8 Volts, the detection circuit which has just been described complies with the condition SE1 specified in the USB standard, which imposes that the voltages applied to the terminals D+ and D− must not exceed a voltage Vose1 equal to 0.8 Volt at the same time.", "FIG. 5 shows a procedure 10 for starting-up the peripheral P according to the invention.", "At the startup of the peripheral, the peripheral controls the opening of the switch I 1 or I 2 depending on whether the USB link of the peripheral is at full or low speed, to disconnect the pull-up resistor Rpu (step 11 ).", "At the following step 12 , the peripheral tests the output signal ER of the detection circuit DCT.", "If the output signal is pulled up, it means that pull-down resistors Rpd of a master device H are linked by the link SL to the data terminals D+, D− of the peripheral P. In that case, the peripheral closes the switch I 1 or I 2 (step 13 ), and tries to establish a communication through its USB port with the master device thus detected (step 14 ).", "If at step 12 the detection signal ER is pulled-down (ER=0), it means that the detection circuit DCT has not detected, on each terminal D+, D−, the presence of a pull-down resistor Rpd having a correct value (conditions (4) not satisfied).", "The procedure 10 then ends without the peripheral trying to establish a communication through its serial port.", "The detection circuit DCT can also comprise a deactivation switch 13 controlled by the peripheral P ( FIG. 4 ).", "This switch allows the detection circuit to be deactivated when the peripheral is live and has detected the presence of a master device H. The switch 13 is for example interposed on a supply line of the voltage generator VGEN connected to the power supply terminal VBUS of the serial port.", "The switch 13 is closed at the start-up of the peripheral, and opened before establishing a communication with the master device, after the detection of the latter.", "It will be clear to those skilled in the art that the device according to the invention is susceptible of several variations.", "Thus, the invention does not necessarily apply to a USB link: it more globally applies to any serial link connecting a master device to a slave device.", "In addition, the impedance detected is not necessarily a pull-down resistor.", "The detection of the impedance is not necessarily performed on a data transmission line of the serial link.", "It can alternately be performed on a supply line of the serial link.", "In the case of a differential serial link, it is not necessary to detect the presence of an impedance on each data terminal D+ and D−.", "Only one of these two terminals can be subjected to the detection performed by the detection circuit.", "In that case, the voltage generator VGEN generates one measure voltage Vm+ or Vm− only, and the detection circuit DCT comprises one detection stage DST 1 or DST 2 only.", "In addition, it is not necessary to compare the measure voltage Vm+, Vm− to a high reference voltage and a low reference voltage.", "To simply detect the presence or the lack of a resistor, comparing the measure voltage with a high reference voltage is sufficient.", "To detect if a terminal of the serial port is linked to the ground, comparing the measure voltage to a low reference voltage is sufficient." ]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supporting objects such as coins, medals, and tokens that are transported, photographed, identified, and sorted. 2. Description of Related Art An example of an apparatus for supporting objects to identify is disclosed in Japanese Unexamined Patent Application Publication No. 10-11629 shown in FIG. 8 . The apparatus of FIG. 8 has a hardened glass 101 and a belt 103 . The belt 103 is driven to transport a coin 105 along the hardened glass 101 . A light source 107 emits light, which is reflected by the coin 105 and is received by a line sensor 109 that converts the received light into an electric signal. The electric signal is used to provide an image of the coin 105 . This related art has a problem that dust easily accumulates on and adheres to the hardened glass 101 , to prevent the apparatus from obtaining a clear image of the coin 105 . The hardened glass 101 is expensive, increasing the manufacturing cost of the apparatus. The hardened glass 101 needs an intricate fitting structure, and therefore, the apparatus needs time and labor when repairing, replacing, and maintaining the same. SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for supporting objects to identify, manufacturable at low cost, capable of providing a correct image of each object, and easy to maintain. In order to accomplish the object, a first aspect of the present invention provides an apparatus for supporting objects to identify, having a belt configured to transport the objects through a photographing section and a linear material stretched across the photographing section in the object transporting direction. Each of the objects transported by the belt to the photographing section is supported between the belt and the linear material and is photographed from the linear material side. A second aspect of the present invention provides the apparatus of the first aspect with a frame configured to be detachably attached to the photographing section and having a photographing window across which the linear material is stretched, upstream and downstream guides arranged at upstream and downstream sides of the photographing window, respectively, configured to support the linear material, a slide face formed at least on the upstream guide and facing the belt, and a recess formed in the slide face, configured to receive the linear material. Each of the objects transported by the belt to the photographing section is slid and guided along the slide face on the upstream side of the photographing window toward the linear material and belt that therebetween support and transport the object. With the apparatus of any one of the first and second aspects, a third aspect of the present invention handles objects that are flat and have disk shapes of different diameters and employs a plurality of the belts and linear materials arranged in parallel with one another, the linear materials being distanced from one another to support and transport the objects of different diameters between the belts and the linear materials. According to the first aspect, the belt transports objects through the photographing section. The linear material is stretched across the photographing section in the object transporting direction. Each of the objects transported by the belt to the photographing section is supported between the belt and the linear material and is photographed from the linear material side. The photographed image of the object substantially entirely shows the object because the linear material on the object is linear and thin, and therefore, the photographed image is properly usable to identify and sort the object. The first aspect can correctly pick up an image of an object that is stably supported between the linear material and the belt. The structure of supporting an object between the linear material and the belt is manufacturable at low cost. The linear material hardly collects dust, and therefore, a correct image of an object can be taken and the object can correctly be identified according to the image. In addition to the effects of the first aspect, the second aspect employs the frame detachably attached to the photographing section and having the photographing window across which the linear material is stretched. The frame is detachable for easy maintenance, and therefore, the linear material is easy to replace. The second aspect further employs the upstream and downstream guides arranged at upstream and downstream sides of the photographing window, respectively, to support the linear material. At least the upstream guide has a slide face facing the belt. The slide face has a recess to receive the linear material. Each of the objects transported by the belt to the photographing section is slid and guided along the slide face on the upstream side of the photographing window toward the linear material and belt that therebetween support and transport the object. At this time, the object is smoothly shifted to the linear material and belt without an edge of the object hitting or damaging the linear material. This improves the durability of the linear material. In addition to the effects of the first and second aspects, the third aspect handles objects that are flat and have disk shapes of different diameters. The third aspect employs a plurality of the belts and linear materials arranged in parallel with one another. The third aspect properly separates the linear materials from one another so that the objects having different diameters are supported and transported between the belts and the linear materials. Namely, the belts and linear materials according to the third aspect can therebetween support each of the objects having different diameters, photograph the object stably supported, and provide a correct image of the object. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view roughly showing an apparatus for supporting objects to identify according to an embodiment of the present invention, the apparatus serving as a sorter to identify and sort tokens; FIG. 2 is a partly broken enlarged view partly showing a transport path and a photographing section in the apparatus of FIG. 1 ; FIG. 3 is an enlarged sectional view partly showing the transport path and photographing section of FIG. 2 ; FIG. 4 is a plan view showing a frame with linear materials in the apparatus of FIG. 1 ; FIG. 5 is a bottom view showing the frame with linear materials of FIG. 4 ; FIG. 6 is a right side view showing the frame with linear materials of FIG. 4 ; FIG. 7 is an enlarged side view showing the linear material in the frame of FIG. 4 ; and FIG. 8 is a perspective view showing an apparatus for supporting objects to identify according to a related art. DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 is a plan view roughly showing an apparatus for supporting objects to identify according to an embodiment of the present invention. In this embodiment, the apparatus serves as a sorter to identify and sort tokens that are used, for example, when playing game machines in a game arcade. In FIG. 1 , the apparatus 1 has a base 3 , a turntable 5 , a side wall 7 formed along the periphery of the turntable 5 , and an opening 9 formed at a part of the side wall 7 . The opening 9 is connected to a transport path 11 having belts to be explained later. In the middle of the transport path 11 , there is a photographing section 13 where a frame 31 is arranged. The downstream side of the transport path 11 is divided into a collecting path 15 and a rejecting path 17 . Objects to be identified and sorted by the apparatus 1 are transported along the transport path 11 . The objects are, for example, flat and disk-like objects and serve as, for example, tokens used in a game arcade. The collecting path 15 passes objects identified as regular, and the rejecting path 17 passes objects identified as irregular. The photographing section 13 has an image-pickup device such as a CCD camera to photograph an object M transported to the photographing section 13 and provide an image of the object M. On the upstream side of the photographing section 13 , there is a sensor (not shown) to detect the object M, and a predetermined time after the detection of the object M, the photographing section 13 activates the CCD camera to pick up an image of the object M. FIGS. 2 and 3 show the details of the transport path 11 and photographing section 13 , in which FIG. 2 is a partly broken enlarged view and FIG. 3 is an enlarged sectional view each partly showing the transport path 11 and photographing section 13 . The transport path 11 consists of a plurality of belts, for example, two belts 19 and 21 that run in parallel with each other along the transport path 11 and are driven from the upstream side toward the downstream side of the transport path 11 as indicated with an arrow mark A in FIG. 2 . The belts 19 and 21 are made of, for example, rubber or resin and transport objects along the transport path 11 and pass the objects through the photographing section 13 . The photographing section 13 has a plurality of linear materials, for example, two strings 27 and 29 . The strings 27 and 29 are arranged in parallel with each other, are stretched in the object transporting direction, and are faced to the belts 19 and 21 . The strings 27 and 29 are linear materials made of, for example, nylon. In this embodiment, they are made from a fishing line. The strings 27 and 29 are distanced from each other. The string 29 is stretched substantially along the center line of the belt 21 to face the belt 21 , and the string 27 is transversally biased from the belt 19 . With this arrangement, the belts 19 and 21 and the strings 27 and 29 can therebetween support and transport an object having an optional diameter, e.g., an object M having a large diameter or an object M 1 having a small diameter. The large and small objects M and M 1 are restricted in their transversal movements by guides 23 and 25 when they are transported along the transport path 11 , so that each object can be positioned within a window 33 of the frame 31 . Irrespective of the position of the small object M 1 whether it is on one or the other side of the window 33 , the strings 27 and 29 surely come over and support the object M 1 . The strings 27 and 29 are fitted to the frame 31 across the window 33 . The window 33 serves as a photographing window when photographing an object (M, M 1 ) at the photographing section 13 with, for example, a CCD camera arranged above the frame 31 . The frame 31 is detachably attached to the base 3 in the photographing section 13 . The frame 31 has long holes 35 on each side of the transport path 11 . Bolts 37 are passed through the long holes 35 and are fastened to the base 3 to fix the frame 31 to the base 3 . With the long holes 35 , the position of the frame 31 is finely adjustable in the photographing section 13 . An object (M, M 1 ) is transported on the belts 19 and 21 to the photographing section 13 . At the photographing section 13 , the object is supported between the strings 27 and 29 and the belts 19 and 21 and is photographed from the string side. The details of the frame 31 and strings 27 and 29 will be explained with reference to FIGS. 4 to 7 in which FIG. 4 is a plan view showing the frame 31 and strings 27 and 29 , FIG. 5 is a bottom view showing the same, FIG. 6 is a right side view showing the same, and FIG. 7 is an enlarged side view showing the same. In FIGS. 3 to 6 , the bottom of the frame 31 is provided with guides 39 and 41 on the upstream and downstream sides of the window 33 , respectively, to support the strings 27 and 29 . The guides 39 and 41 are each quadrate and protrude toward the belts 19 and 21 . The guides 39 and 41 have slide faces 43 and 45 , respectively. The slide faces 43 and 45 are flat and are substantially parallel to the belts 19 and 21 . Each of the slide faces 43 and 45 is provided with recesses 47 . FIG. 7 shows the string 27 received in the recess 47 of the slide face 43 . The surface of the string 27 does not protrude out of the slide face 43 and is substantially flush with the slide face 43 . The same configuration is applied to the string 27 in the recess 47 of the slide face 45 and the string 29 in the recesses 47 of the slide faces 43 and 45 . From the upstream side of the window 33 , an object (M, M 1 ) is transported to the window 33 , and at there, is supported between the strings 27 and 29 and the belts 19 and 21 . On the downstream side of the window 33 , the object is shifted to the guide face 45 from between the strings 27 and 29 and the belts 19 and 21 . On the upstream side of the guide 39 , the frame 31 has through holes 49 a and 49 b . On the downstream side of the guide 41 , the frame 31 has through holes 51 a and 51 b . On the upstream side of the through holes 49 a and 49 b , the frame 31 has threaded holes 53 into which bolts 55 , 57 , and 59 are screwed from the top surface side of the frame 31 . The bolts 55 , 57 , and 59 have lock nuts 61 , respectively, to fix ends 63 and 65 of the strings 27 and 29 . According to the embodiment, the strings 27 and 29 are made from a fishing line. The fishing line is wound around the bolt 59 at the end 63 , is hooked around the bolt 57 , is passed through the through hole 49 a to the bottom face of the frame 31 , is extended through the recess 47 of the slide face 43 , and is stretched across the window 33 to form the string 27 . Thereafter, the fishing line is extended in the recess 47 of the slide face 45 , is passed through the through hole 51 a , and is pulled out of the top surface of the frame 31 . Further, the fishing line is passed through the through hole 51 b , is extended in the recess 47 of the slide face 45 , and is stretched across the window 33 to form the line material 29 . Thereafter, the fishing line is passed through the recess 47 of the slide face 43 and the through hole 49 b and is pulled out of the top surface of the frame 31 . Then, the fishing line is hooked around the bolt 57 , is wound around the bolt 55 , and is fixed at the end 65 with the lock nut 61 of the bolt 55 . In this way, the strings 27 and 29 can easily be arranged on the frame 31 . Operation of the apparatus 1 according to the embodiment will be explained. In FIG. 1 , the turntable 5 is turned, and objects M move toward the periphery of the turntable 5 due to centrifugal force. The objects M are pressed against the side wall 7 , are moved along the side wall 7 , and are shifted onto the transport path 11 through the opening 9 . In the transport path 11 , the objects M are transported on the belts 19 and 21 in the direction of the arrow mark A. At this time, the guides 23 and 25 restrict the transversal movements of the objects M. Each of the objects M transported to the photographing section 13 is supported between the strings 27 and 29 and the belts 19 and 21 . When one object M is transported to the strings 27 and 29 and the guides 23 and 25 , the object M is guided to the guide 39 as shown in FTC. 3 , and then, the object M is smoothly supported between the strings 27 and 29 and the belts 19 and 21 . The slide face 43 guides the object M so that a corner 67 of the object M may not directly hit or damage the strings 27 and 29 . This arrangement improves the durability of the strings 27 and 29 . Thereafter, the object M enters the window 33 and is photographed. At this time, the object M is stably supported between the belts 19 and 21 and the strings 27 and 29 , and therefore, the image-pickup device such as a CCD camera can correctly photograph the object M from the string side. The strings 27 and 29 are made from, for example, a fishing line, and therefore, are sufficiently thin to provide a clear whole image of the object M. With this image, the object M can correctly be identified and sorted. Thereafter, the object M is transported to the downstream side of the window 33 and is shifted to the slide face 45 of the guide 41 from between the strings 27 and 29 and the belts 19 and 21 . When the object M leaves the strings 27 and 29 , the guide 41 prevents the corner 67 of the object M from twisting the strings 27 and 29 , thereby improving the durability of the strings 27 and 29 . The object M is identified and sorted according to the image taken from the object M. If the object M is determined to be genuine, it is sent to the collecting path 15 , and if it is determined to be not genuine, to the rejecting path 17 . For the sake of replacement of the strings 27 and 29 , a plurality of frames 31 each provided with strings 27 and 29 may be prepared in advance. Then, the frame 31 with the strings 27 and 29 may easily be replaced with another. This realizes easy maintenance of the strings 27 and 29 . Further, the strings 27 and 29 can easily be removed from and fixed to the frame 31 by loosening and fastening the lock nuts 61 . This also realizes easy maintenance of the strings 27 and 29 . The present invention is achievable in many other forms. For example, the two belts 19 and 21 may be replaced with a single belt. The strings 27 and 29 may directly be attached to and stretched along the base 3 . The strings 27 and 29 may be made of any linear material. The objects to be identified and sorted according to the present invention may be tokens used in game arcades, coins, medals, and the like. The objects to be identified and sorted according to the present invention may be flat and may have circular shapes or any other shapes.
An apparatus for supporting objects to identify is manufacturable at low cost and is capable of providing correct images of the objects. The apparatus has belts ( 19, 21 ) to transport the objects (M) through a photographing section ( 13 ). The apparatus also has strings ( 27, 29 ) stretched across the photographing section in the object transporting direction. Each of the objects transported by the belts to the photographing section is supported between the belts and the strings and is photographed from the string side.
Summarize the key points of the given patent document.
[ "BACKGROUND OF THE INVENTION 1.", "Field of the Invention The present invention relates to an apparatus for supporting objects such as coins, medals, and tokens that are transported, photographed, identified, and sorted.", "Description of Related Art An example of an apparatus for supporting objects to identify is disclosed in Japanese Unexamined Patent Application Publication No. 10-11629 shown in FIG. 8 .", "The apparatus of FIG. 8 has a hardened glass 101 and a belt 103 .", "The belt 103 is driven to transport a coin 105 along the hardened glass 101 .", "A light source 107 emits light, which is reflected by the coin 105 and is received by a line sensor 109 that converts the received light into an electric signal.", "The electric signal is used to provide an image of the coin 105 .", "This related art has a problem that dust easily accumulates on and adheres to the hardened glass 101 , to prevent the apparatus from obtaining a clear image of the coin 105 .", "The hardened glass 101 is expensive, increasing the manufacturing cost of the apparatus.", "The hardened glass 101 needs an intricate fitting structure, and therefore, the apparatus needs time and labor when repairing, replacing, and maintaining the same.", "SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for supporting objects to identify, manufacturable at low cost, capable of providing a correct image of each object, and easy to maintain.", "In order to accomplish the object, a first aspect of the present invention provides an apparatus for supporting objects to identify, having a belt configured to transport the objects through a photographing section and a linear material stretched across the photographing section in the object transporting direction.", "Each of the objects transported by the belt to the photographing section is supported between the belt and the linear material and is photographed from the linear material side.", "A second aspect of the present invention provides the apparatus of the first aspect with a frame configured to be detachably attached to the photographing section and having a photographing window across which the linear material is stretched, upstream and downstream guides arranged at upstream and downstream sides of the photographing window, respectively, configured to support the linear material, a slide face formed at least on the upstream guide and facing the belt, and a recess formed in the slide face, configured to receive the linear material.", "Each of the objects transported by the belt to the photographing section is slid and guided along the slide face on the upstream side of the photographing window toward the linear material and belt that therebetween support and transport the object.", "With the apparatus of any one of the first and second aspects, a third aspect of the present invention handles objects that are flat and have disk shapes of different diameters and employs a plurality of the belts and linear materials arranged in parallel with one another, the linear materials being distanced from one another to support and transport the objects of different diameters between the belts and the linear materials.", "According to the first aspect, the belt transports objects through the photographing section.", "The linear material is stretched across the photographing section in the object transporting direction.", "Each of the objects transported by the belt to the photographing section is supported between the belt and the linear material and is photographed from the linear material side.", "The photographed image of the object substantially entirely shows the object because the linear material on the object is linear and thin, and therefore, the photographed image is properly usable to identify and sort the object.", "The first aspect can correctly pick up an image of an object that is stably supported between the linear material and the belt.", "The structure of supporting an object between the linear material and the belt is manufacturable at low cost.", "The linear material hardly collects dust, and therefore, a correct image of an object can be taken and the object can correctly be identified according to the image.", "In addition to the effects of the first aspect, the second aspect employs the frame detachably attached to the photographing section and having the photographing window across which the linear material is stretched.", "The frame is detachable for easy maintenance, and therefore, the linear material is easy to replace.", "The second aspect further employs the upstream and downstream guides arranged at upstream and downstream sides of the photographing window, respectively, to support the linear material.", "At least the upstream guide has a slide face facing the belt.", "The slide face has a recess to receive the linear material.", "Each of the objects transported by the belt to the photographing section is slid and guided along the slide face on the upstream side of the photographing window toward the linear material and belt that therebetween support and transport the object.", "At this time, the object is smoothly shifted to the linear material and belt without an edge of the object hitting or damaging the linear material.", "This improves the durability of the linear material.", "In addition to the effects of the first and second aspects, the third aspect handles objects that are flat and have disk shapes of different diameters.", "The third aspect employs a plurality of the belts and linear materials arranged in parallel with one another.", "The third aspect properly separates the linear materials from one another so that the objects having different diameters are supported and transported between the belts and the linear materials.", "Namely, the belts and linear materials according to the third aspect can therebetween support each of the objects having different diameters, photograph the object stably supported, and provide a correct image of the object.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view roughly showing an apparatus for supporting objects to identify according to an embodiment of the present invention, the apparatus serving as a sorter to identify and sort tokens;", "FIG. 2 is a partly broken enlarged view partly showing a transport path and a photographing section in the apparatus of FIG. 1 ;", "FIG. 3 is an enlarged sectional view partly showing the transport path and photographing section of FIG. 2 ;", "FIG. 4 is a plan view showing a frame with linear materials in the apparatus of FIG. 1 ;", "FIG. 5 is a bottom view showing the frame with linear materials of FIG. 4 ;", "FIG. 6 is a right side view showing the frame with linear materials of FIG. 4 ;", "FIG. 7 is an enlarged side view showing the linear material in the frame of FIG. 4 ;", "and FIG. 8 is a perspective view showing an apparatus for supporting objects to identify according to a related art.", "DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 is a plan view roughly showing an apparatus for supporting objects to identify according to an embodiment of the present invention.", "In this embodiment, the apparatus serves as a sorter to identify and sort tokens that are used, for example, when playing game machines in a game arcade.", "In FIG. 1 , the apparatus 1 has a base 3 , a turntable 5 , a side wall 7 formed along the periphery of the turntable 5 , and an opening 9 formed at a part of the side wall 7 .", "The opening 9 is connected to a transport path 11 having belts to be explained later.", "In the middle of the transport path 11 , there is a photographing section 13 where a frame 31 is arranged.", "The downstream side of the transport path 11 is divided into a collecting path 15 and a rejecting path 17 .", "Objects to be identified and sorted by the apparatus 1 are transported along the transport path 11 .", "The objects are, for example, flat and disk-like objects and serve as, for example, tokens used in a game arcade.", "The collecting path 15 passes objects identified as regular, and the rejecting path 17 passes objects identified as irregular.", "The photographing section 13 has an image-pickup device such as a CCD camera to photograph an object M transported to the photographing section 13 and provide an image of the object M. On the upstream side of the photographing section 13 , there is a sensor (not shown) to detect the object M, and a predetermined time after the detection of the object M, the photographing section 13 activates the CCD camera to pick up an image of the object M. FIGS. 2 and 3 show the details of the transport path 11 and photographing section 13 , in which FIG. 2 is a partly broken enlarged view and FIG. 3 is an enlarged sectional view each partly showing the transport path 11 and photographing section 13 .", "The transport path 11 consists of a plurality of belts, for example, two belts 19 and 21 that run in parallel with each other along the transport path 11 and are driven from the upstream side toward the downstream side of the transport path 11 as indicated with an arrow mark A in FIG. 2 .", "The belts 19 and 21 are made of, for example, rubber or resin and transport objects along the transport path 11 and pass the objects through the photographing section 13 .", "The photographing section 13 has a plurality of linear materials, for example, two strings 27 and 29 .", "The strings 27 and 29 are arranged in parallel with each other, are stretched in the object transporting direction, and are faced to the belts 19 and 21 .", "The strings 27 and 29 are linear materials made of, for example, nylon.", "In this embodiment, they are made from a fishing line.", "The strings 27 and 29 are distanced from each other.", "The string 29 is stretched substantially along the center line of the belt 21 to face the belt 21 , and the string 27 is transversally biased from the belt 19 .", "With this arrangement, the belts 19 and 21 and the strings 27 and 29 can therebetween support and transport an object having an optional diameter, e.g., an object M having a large diameter or an object M 1 having a small diameter.", "The large and small objects M and M 1 are restricted in their transversal movements by guides 23 and 25 when they are transported along the transport path 11 , so that each object can be positioned within a window 33 of the frame 31 .", "Irrespective of the position of the small object M 1 whether it is on one or the other side of the window 33 , the strings 27 and 29 surely come over and support the object M 1 .", "The strings 27 and 29 are fitted to the frame 31 across the window 33 .", "The window 33 serves as a photographing window when photographing an object (M, M 1 ) at the photographing section 13 with, for example, a CCD camera arranged above the frame 31 .", "The frame 31 is detachably attached to the base 3 in the photographing section 13 .", "The frame 31 has long holes 35 on each side of the transport path 11 .", "Bolts 37 are passed through the long holes 35 and are fastened to the base 3 to fix the frame 31 to the base 3 .", "With the long holes 35 , the position of the frame 31 is finely adjustable in the photographing section 13 .", "An object (M, M 1 ) is transported on the belts 19 and 21 to the photographing section 13 .", "At the photographing section 13 , the object is supported between the strings 27 and 29 and the belts 19 and 21 and is photographed from the string side.", "The details of the frame 31 and strings 27 and 29 will be explained with reference to FIGS. 4 to 7 in which FIG. 4 is a plan view showing the frame 31 and strings 27 and 29 , FIG. 5 is a bottom view showing the same, FIG. 6 is a right side view showing the same, and FIG. 7 is an enlarged side view showing the same.", "In FIGS. 3 to 6 , the bottom of the frame 31 is provided with guides 39 and 41 on the upstream and downstream sides of the window 33 , respectively, to support the strings 27 and 29 .", "The guides 39 and 41 are each quadrate and protrude toward the belts 19 and 21 .", "The guides 39 and 41 have slide faces 43 and 45 , respectively.", "The slide faces 43 and 45 are flat and are substantially parallel to the belts 19 and 21 .", "Each of the slide faces 43 and 45 is provided with recesses 47 .", "FIG. 7 shows the string 27 received in the recess 47 of the slide face 43 .", "The surface of the string 27 does not protrude out of the slide face 43 and is substantially flush with the slide face 43 .", "The same configuration is applied to the string 27 in the recess 47 of the slide face 45 and the string 29 in the recesses 47 of the slide faces 43 and 45 .", "From the upstream side of the window 33 , an object (M, M 1 ) is transported to the window 33 , and at there, is supported between the strings 27 and 29 and the belts 19 and 21 .", "On the downstream side of the window 33 , the object is shifted to the guide face 45 from between the strings 27 and 29 and the belts 19 and 21 .", "On the upstream side of the guide 39 , the frame 31 has through holes 49 a and 49 b .", "On the downstream side of the guide 41 , the frame 31 has through holes 51 a and 51 b .", "On the upstream side of the through holes 49 a and 49 b , the frame 31 has threaded holes 53 into which bolts 55 , 57 , and 59 are screwed from the top surface side of the frame 31 .", "The bolts 55 , 57 , and 59 have lock nuts 61 , respectively, to fix ends 63 and 65 of the strings 27 and 29 .", "According to the embodiment, the strings 27 and 29 are made from a fishing line.", "The fishing line is wound around the bolt 59 at the end 63 , is hooked around the bolt 57 , is passed through the through hole 49 a to the bottom face of the frame 31 , is extended through the recess 47 of the slide face 43 , and is stretched across the window 33 to form the string 27 .", "Thereafter, the fishing line is extended in the recess 47 of the slide face 45 , is passed through the through hole 51 a , and is pulled out of the top surface of the frame 31 .", "Further, the fishing line is passed through the through hole 51 b , is extended in the recess 47 of the slide face 45 , and is stretched across the window 33 to form the line material 29 .", "Thereafter, the fishing line is passed through the recess 47 of the slide face 43 and the through hole 49 b and is pulled out of the top surface of the frame 31 .", "Then, the fishing line is hooked around the bolt 57 , is wound around the bolt 55 , and is fixed at the end 65 with the lock nut 61 of the bolt 55 .", "In this way, the strings 27 and 29 can easily be arranged on the frame 31 .", "Operation of the apparatus 1 according to the embodiment will be explained.", "In FIG. 1 , the turntable 5 is turned, and objects M move toward the periphery of the turntable 5 due to centrifugal force.", "The objects M are pressed against the side wall 7 , are moved along the side wall 7 , and are shifted onto the transport path 11 through the opening 9 .", "In the transport path 11 , the objects M are transported on the belts 19 and 21 in the direction of the arrow mark A. At this time, the guides 23 and 25 restrict the transversal movements of the objects M. Each of the objects M transported to the photographing section 13 is supported between the strings 27 and 29 and the belts 19 and 21 .", "When one object M is transported to the strings 27 and 29 and the guides 23 and 25 , the object M is guided to the guide 39 as shown in FTC.", "3 , and then, the object M is smoothly supported between the strings 27 and 29 and the belts 19 and 21 .", "The slide face 43 guides the object M so that a corner 67 of the object M may not directly hit or damage the strings 27 and 29 .", "This arrangement improves the durability of the strings 27 and 29 .", "Thereafter, the object M enters the window 33 and is photographed.", "At this time, the object M is stably supported between the belts 19 and 21 and the strings 27 and 29 , and therefore, the image-pickup device such as a CCD camera can correctly photograph the object M from the string side.", "The strings 27 and 29 are made from, for example, a fishing line, and therefore, are sufficiently thin to provide a clear whole image of the object M. With this image, the object M can correctly be identified and sorted.", "Thereafter, the object M is transported to the downstream side of the window 33 and is shifted to the slide face 45 of the guide 41 from between the strings 27 and 29 and the belts 19 and 21 .", "When the object M leaves the strings 27 and 29 , the guide 41 prevents the corner 67 of the object M from twisting the strings 27 and 29 , thereby improving the durability of the strings 27 and 29 .", "The object M is identified and sorted according to the image taken from the object M. If the object M is determined to be genuine, it is sent to the collecting path 15 , and if it is determined to be not genuine, to the rejecting path 17 .", "For the sake of replacement of the strings 27 and 29 , a plurality of frames 31 each provided with strings 27 and 29 may be prepared in advance.", "Then, the frame 31 with the strings 27 and 29 may easily be replaced with another.", "This realizes easy maintenance of the strings 27 and 29 .", "Further, the strings 27 and 29 can easily be removed from and fixed to the frame 31 by loosening and fastening the lock nuts 61 .", "This also realizes easy maintenance of the strings 27 and 29 .", "The present invention is achievable in many other forms.", "For example, the two belts 19 and 21 may be replaced with a single belt.", "The strings 27 and 29 may directly be attached to and stretched along the base 3 .", "The strings 27 and 29 may be made of any linear material.", "The objects to be identified and sorted according to the present invention may be tokens used in game arcades, coins, medals, and the like.", "The objects to be identified and sorted according to the present invention may be flat and may have circular shapes or any other shapes." ]
BACKGROUND OF THE INVENTION This invention belongs to the field of material haulage vehicles and more particularly to improvements in the type commonly known as "shuttle cars" for hauling loose mined material in underground mines. Shuttle cars must operate in mine rooms and entries where the bottom and the top undulate, where height and space restrictions are severe, and where turning radiuses are tight. Yet they must provide large capacity along with rapid loading, carrying, and unloading of mined material in great tonnages. As shown for example in Russell U.S. Pat. No. 2,962,176, vertically articulated shuttle cars have been developed for low height, undulating passages. As the contour of the floor changes, fore and aft body sections pivot about a horizontal axis to prevent the underside or topside of the car from hanging up on the floor or roof. However, in many mines it would be physically impossible for shuttle cars of adequate capacity to make the tight turns encountered without "brushing" the corners, i.e. blasting them off to eliminate the sharp turns. This, of course, is wasteful of labor and energy and could be avoided if shuttle cars could articulate horizontally to avoid the sharp corners, as shown in FIG. 16. Attempts have been made to provide horizontal articulation in a mine haulage vehicle by using ejector scoops and shovel loaders. Examples are shown in U.S. Pat. No. 3,937,345 and the following equipment advertisements in the April 1976 Coal Age: pages 58 and 59, showing ejector buckets manufactured by Wagner Mining Equipment Co.; page 166, an ejector bucket manufactured by Fairchild Inc.; page 173, a scoop manufactured by Owens Mfg. Inc.; page 196, ram cars manufactured by Dresser Industries; page 205, a scoop/tractor manufactured by Pyott-Boone, Inc.; page 268, an ejector scoop manufactured by S & S Corporation; and pages 374, 375, an ejector scoop manufactured by Eimco Mining Machinery. Although these units have a tractor section and a cargo section pivotally interconnected for horizontal swinging movement, they have a very serious drawback in that loading and unloading must both be done from the scoop or shovel end, requiring the machine to make two full 180° turns on each trip between the loading and unloading sites. This takes time and often requires brushing out a turn-around area which otherwise would be unnecessary. There is a need for a horizontally articulated mine haulage vehicle which can receive a load at one end, convey it in one direction through the vehicle, and discharge it from the other end without turning the vehicle around. SUMMARY OF THE INVENTION It is therefore the major object of the present invention to provide an improved shuttle car with articulating pivot means enabling relative horizontal swinging movement between adjacent main body sections, and a horizontally flexible, orbitally movable conveyor means extending through the vehicle. Another object of the present invention is to provide a mine haulage vehicle having an elongated body with a front outbye section and a rear inbye section which are interconnected at adjacent ends by vertical pivot means to enable the body sections to swing freely horizontally, relative to each other. The vehicle has a horizontally flexible centerstrand chain conveyor, orbitally movable about sprockets at opposite ends, the conveyor having an upper-load-carrying run, movable along the bottom of a cargo-carrying compartment in the inbye section and discharging from the front end of the outbye section, to provide one-direction loading and unloading while enabling the body to swing horizontally so it can negotiate sharp turns. Another object is to provide a haulage vehicle as described in which the outbye section has an elevatable boom for the conveyor, enabling it to discharge into an elevated conveyor or mine car. Another object is to provide a horizontally-articulated vehicle as described in which the pivot means includes vertically-spaced upper and lower horizontal rear portions of the front body section, pivotally connected respectively to vertically-spaced upper and lower horizontal front portions of the rear body section, the carrying reach of the conveyor being movable across the top of the pivotally-connected upper horizontal portions of the two sections, and the return reach of the conveyor being movable through the space between the pivotally-connected upper and lower horizontal portions of the two sections, thereby enabling the longitudinal axis of the conveyor to intersect the pivotal axis between the body sections while permitting horizontal articulation of the vehicle and straight-through transfer of material between the cargo-carrying compartment and the discharge end. Another object is to provide a mine haulage vehicle as described in which a pair of vertical push blades are provided on opposite sides of the conveyor in the cargo compartment. Another object is to support one of the body sections by wheels on opposite sides, each of the wheels being supported on a separate subframe independently of the other wheel, each subframe being pivotally mounted and tiltable against springs to provide a flexible suspension for the vehicle. Other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are plan and side views respectively of a mine haulage vehicle illustrating one form of the present invention, FIG. 1 being shown in two sections, FIGS. 1A and 1B, and FIG. 2 being shown in two sections, FIGS. 2A and 2B; FIG. 3 is an enlarged fragmentary view of FIG. 1A; FIG. 4 is a combined vertical sectional and rear view of FIG. 1B taken generally in the direction of the arrows 4--4; FIG. 5 is an enlarged fragmentary cross-sectional view of FIG. 1A taken along line 5--5; FIG. 6 is an enlarged top plan view of one of the wheel assemblies shown in FIG. 1A; FIG. 7 is a partially cut-away side view of FIG. 6; FIG. 8 is a top plan view of the discharge boom; FIG. 9 is a side view of FIG. 8; FIG. 10 is a top plan view of the front, outbye body section; FIG. 11 is a side view of FIG. 10; FIG. 12 is a fragmentary cross-sectional view of FIG. 11 taken along line 12--12, together with an associated portion of one of the wheel-supporting subframes; FIG. 13 is a top plan view of the rear, inbye cargo-carrying body section; FIG. 14 is a side view of FIG. 13; FIG. 15 is a fragmentary view of FIG. 7 taken along line 15--15; FIG. 16 is a top plan view of the mine haulage vehicle in an articulated condition, as it makes a turn around a sharp corner in a mine; and FIG. 17 is a side view of the vehicle with its discharge boom in a raised position for elevated load discharge onto a conveyor. Like parts are referred to by like reference characters. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the specific embodiment of the invention in the drawings, and particularly to FIGS. 1, 2 and 16, the mine haulage vehicle is generally designated 20. It comprises an elongated body having a front or outbye section 22 and a rear or inbye section 24, the front section having an elevatable discharge boom 26. The vehicle is supported on pairs of individually self-powered front and rear wheel assemblies 28 and 30 respectively. The body sections are interconnected at adjacent ends by pivot means generally designated 32 enabling them to swing freely horizontally relative to each other about a vertical pivot axis 34; this enables steering the vehicle in a manner to clear corners as shown in FIG. 16. An orbitally movable, horizontally flexible, center strand chain flight conveyor 36 is trained between a front drive sprocket 38 and a rear idler sprocket 40. The above basic components will now be described in more detail. The frame of the rear body section 24 has a central, horizontal, longitudinally extending plate 42 for guiding the conveying run of the conveyor 36. An inclined plate section 46 guides the conveying run upward to a forwardly extending fan-shaped plate 48, the latter having a circularly extending leading edge 50 centered at axis 34. Channel members 54 (FIG. 4) are affixed as by welding to opposite edges of the plate 42, providing guidance and support for both the conveying run 44 and return run 45 of the conveyor 36. The conveyor comprises a conventional center chain 56 with flights 58. Universal connecting links 60 enable the chain to flex vertically about the sprockets 38, 40, and horizontally when the two body sections are articulated about the axis 34. The channel members 54 have upper inwardly extending flanges 62, functioning as hold-downs for the ends of the flights 58, and lower inwardly extending flanges 64 supporting the flights in the return run. A load or cargo compartment 66 is provided in the inbye body section 24 and is defined by conveyor floor plates 42 and 68, side walls 70, 72, 74, 76, 77 and rear wall 78. In addition, the load or cargo-carrying compartment is defined by upwardly and outwardly flaring sideboard plates 80 and 82. A pair of push blades 84, 84, are provided on opposite sides of the conveyor at the rear end of the cargo compartment 66. This facilitates a complete transfer of material to the conveyor during unloading, from the bottom plates 68 of the cargo compartment. Each push blade is movable toward and away from the conveyor between solid and broken line positions shown in FIG. 1B by hydraulic piston means 86. This comprises an outer cylinder 88 having a flange 90 fastened to the blade 84 by bolts 92. The usual arrangement (not shown) of multiple telescopic cylinders and pistons are provided internally of the outer cylinder 88 to provide the required range of movement for the push blade. That internal arrangement includes an inner piston shaft 94 extending through sidewall 76 and fastened between ribs 96, 96. Suitable conventional hydraulic inner ports and passages (not shown) are provided enabling the piston and cylinder means 86 to move the blades 84 reversibly between operative positions shown. Curved, vertical, forwardly diverging side plates 98, 98 are fastened as by welding to the margins of the fan-shaped plate 48, extending up to the circular edge 50. Conventional spring sideplates 100, 100 are fastened as by welding or bolting at their rear ends 102 to the forward ends of the conveyor through sidewalls 104. As best shown in FIGS. 5 and 14, a lower level conveyor guide plate 106 extends forwardly from the rear body section 24 immediately below the plate 48. Each wheel assembly 30 includes a rubber-tired wheel rotatively journaled in a gear box 108, which is fastened to the adjacent sidewall 72. An electric tram motor 110 is mounted on the adjacent sidewall 112 and is connected via drive shaft 114 and universal couplings 116 and 117 to drive the wheel 107 through the gear box. The rotor 118 for a disc brake is driven by the motor. It is located immediately adjacent the coupling 116. The brake comprises no part of the present invention so the caliper pads and other components are not shown. Each of the tram motors 110 may be energized by electric conductors and controls forming no part of the present invention and therefore are not shown. At the rear end of body section 24, the rear idler sprocket 40 is mounted on a cross-shaft 120, the ends of which are journaled within bearing boxes 122 which are guided for fore and aft adjustment movement along channel members 54. A slot (not shown) is provided in each channel member to enable such fore and aft movement and the center chain 56 is tensioned by a pair of springs 124 acting between the journal boxes 122 and brackets 126. If desired, suitable conventional means (not shown) may be employed to vary the compression of the spring and therefore the tension in the conveyor chain. The front, outbye body section 22 has a box-type central portion best shown in FIGS. 1A, 5, 10 and 11 consisting of upper and lower floor plates 128 and 130 and sidewalls 132, 132. The top surfaces of these floor plates are level respectively with the top surfaces of floor plates 48 and 106 to provide uninterrupted support for the upper and lower runs of the conveyor. The rear edges 134, 134a of these plates are curved to conform to the circularly extending leading edges 50, 50a of plates 48 and 106. An important feature of the present invention is the extremely heavy-duty construction of the pivot means 32 which provides the horizontally swingable connection between the front and rear body sections and enables the conveyor upper and lower runs to operate through the pivot axis 34 at all angular positions, up to at least 45° in either direction. Heavy crossbars 138, 138a are welded beneath the plates 128, 130 and they have similarly heavy rear plate extensions 140, 140a welded thereon. Steel gussets 143 welded beneath the plate 140 furnish supplemental support. The plates are counterbored as at 142, 142a for vertically-spaced bearing elements now to be described. Refer to FIG. 5. A ball- or roller-type turntable side and thrust bearing 144 has an outer race 146 and an inner race 148. Each outer race 146 is held in the counterbore 142 or 142a by means of cap bolts 150 which are threaded into the extensions 140, 140a. The inner races 148 are seated within counterbores 152, 152a in two circular retainer members 154 and 156. These are identical except for the apertures provided for the cap bolt fasteners 158 and 160, which, as shown in FIG. 5, are arranged respectively head up and head down. To illustrate the size of the bearing components required, the bearing balls 162 are 1 inch in diameter and are arranged on a pitch diameter of 18.875". The outer diameter of the outer race and the inner diameter of the inner race are respectively 22.5" and 15.5" respectively. There are twenty-four cap bolts 158 with their heads seated within counterbores 164 in the top plate 48. They extend through bores 166 in the inner race, and at their opposite ends are screwed into threaded bores 168 in the member 154. The heads of cap bolts 160 are seated within counterbores 170 in the underside of retainer disc 156. They extend upward through the bores 166 in the inner race 148 and are screw-connected into threaded openings 172 in plate 106. As best shown in FIGS. 1A and 5, a small retainer tab 174 is fastened to the top edge of each sidewall 132 and is spaced inwardly to provide sliding clearance for the flexible spring sideplates 100. These slide between the walls 132 and tabs 174 when the body sections are swung relative to one another. The lower floor plate 130 of the front body section 22 supports the conveyor return run 45. The forward portion of the body section 22 has a wide bottom frame plate 178 upon which various other compartments and components are supported. A pair of vertical frame plates 180 are spaced apart sufficiently that the discharge boom 26 will fit between them. The rear ends of the plates 180 and the forward ends of the sidewalls 132 are separated by means of spacers 182 (FIG. 10) providing room between them for the rearward ends of the sidewalls 184 of the discharge boom. Separate, aligned pivot stub shafts 186 are supported between the overlapping portions of the members 132 and 180. These fit within the pivot openings 188 (FIG. 9) in the discharge boom sidewalls enabling the latter to be tilted up and down about a tilt axis 190 (FIGS. 8 and 10). To further strengthen the frame of front body section 22, a vertical reinforcing plate 192 is welded along each side edge of frame plate 178, and a vertical plate 194 is welded along the forward edge just beneath the conveyor and providing a mounting for elevating cylinder 196. The front body section 22 has a number of other components which are individually conventional in the field of mining machinery and shuttle cars, so they will not be described in detail. Briefly however these include a pair of electric tram motors 198 fixedly mounted on the outsides of vertical plates 192 by brackets 200 and 202. An electric motor starter box 204 is provided for the four motors. An electric motor 206 is connected to drive a hydraulic pump 208 which supplies the various hydraulic oil pressure requirements for the vehicle. A cable reel drum 210 is mounted within a cable reel compartment 212 and is driven by a small hydraulic motor 214. A spooler 216 controls the laying of cable (not shown) on the drum, the cable supplying the electric power requirements of the various electrically driven components. An operator's compartment 218 contains the usual facilities, not shown, enabling an operator to sit inside, under a protective steel canopy, and tram the shuttle car in either direction, steer it, and operate the various movable components. The elevatable boom 26 has upper and lower guide plates 220 and 222 for the upper and lower runs of the conveyor. A conveyor motor 224 drives the drive sprocket 38 through a gear reducer 226, both the motor and reducer being fixed on the side of the discharge boom as shown. The elevating cylinder 196 is pivotally connected at opposite ends to the brackets 228 on the front body section and brackets 230 on the underside of the boom to tilt the latter up and down about the axis 190 when the cylinder is actuated. The flexible supports for the front wheel assemblies 28 will now be described. Refer first to FIGS. 6, 7, 12 and 15. Each wheel assembly 28 comprises a sub-frame 231 consisting of a main vertical plate 232, a horizontal base plate 234, a vertical front end plate 236, and vertical ribs 238, 240 and 242. A rubber-tired wheel 244 is rotatably supported on a gear reducer 246 which, in turn, is mounted by flange 248 and bolts 250 on the main plate 232. Each wheel is driven by one of the tram motors 198 through universal joints 252, 254 and the above-mentioned reducer 246. Each sub-frame 231 has its rear end portion pivoted for up and down movement about an axis 256. The forward end portion is free to move against the compression of springs 258. The latter are retained at their bottoms within cup-like seats 260. The upper ends of springs 258 are seated within downwardly facing cup-like seats similar to those designated 260, in an adjustment bar 262. A pair of adjusting bolts 264 are threadedly engaged through a mounting block 266 strengthened by gibs 267. The bottoms of these ajusting bolts bear against the top side of the adjustment bar 262. Rotation of the screws 264, therefore, adjust the level of the front end of the machine. As shown in FIGS. 6, 7 and 15, the sub-frame 231 is journaled for up and down rocking movement on a post 268 affixed as by welding to the vertical plate 192 and stiffened by a steel gusset 269. A cylindrical shaft portion 270 is journaled within a sleeve bearing 272 which, in turn, is retained within a split bearing block 274, the two halves of which are held together by socket head cap screws 276 and 278. A nut 275 threaded to the end of each shaft 268 holds the corresponding sub-frame 231 assembled. At the front, tiltable, end of the sub-frame 231, it is guided against excessive transverse movement by a slide block 280 attached to it as by welding. As shown in FIGS. 7 and 12, this fits between vertical guides 282 which are welded to the back wall of the starter box 204. A pair of steering cylinders 284 are pivotally connected between mounts 286 and 288 on the rear and front body sections respectively. To simplify the drawings and description, inlet and outlet ports and interconnecting tubing and control valves have purposely been omitted from the hydraulic components because the operation of these components will be obvious to any person skilled in the art. Briefly, however, the boom elevating cylinder 196 may be either a single-acting cylinder or a double-acting cylinder, preferably the latter. The reel hydraulic motor 214 will preferably be reversible. The steering cylinders 284 must be reversible to steer in both directions and will be interconnected so that pressure will be applied concurrently to the head end of one and the rod end of the other so that they both cooperate in the steering action in both directions. In use, the mine haulage vehicle 20 will be positioned just outbye of a mining machine working at a face, with the cargo compartment 66 in position to receive coal or other mined material from the rear boom of the mining machine. In this position both the hydraulic piston and cylinder means 86 will be contracted to their maximum thereby drawing the push blades 84 outward against the sidewalls 76. As the compartment is loaded, the operator will periodically enerqize the conveyor motor 224 to move the conveyor and thereby fill the vehicle for its full length. When the vehicle is thus completely filled from one end to the other and mounded up to the extent permitted by head room in the mine, the operator in compartment 218 trams it in an outbye direction to a transfer point, usually a fixed rubber belt or mine car. A typical intersection in an underground mine is shown in FIG. 16 where the haulage vehicle is shown horizontally articulated (through the action of steering cylinders 284) enabling it to negotiate the sharp turns. It is obvious by inspection of FIG. 16 that it is only the result of the horizontal articulation of the two body sections about the pivot means 32 that this vehicle can operate in such tight quarters. When the vehicle reaches the main haulage conveyor 290 as shown in FIG. 17, cylinder 196 will be actuated to elevate the discharge boom over the conveyor, as shown. The above described arrangement is illustrative of a small number of many possible specific embodiments of this invention. Other arrangements can readily be devised in accordance with the principles disclosed by those skilled in the art without departing from the spirit and scope of the invention.
A mine haulage vehicle comprising a body having front and rear sections which are pivotally interconnected at adjacent ends enabling them to swing freely in a horizontal plane relative to each other about a vertical pivot axis. The body has a pair of ground-engaging wheels on each of the body sections. The vehicle is steered by hydraulic cylinders connected between the body sections for swinging them about the pivot axis. The body sections have aligned trough-shaped compartments extending substantially its full length and containing a horizontally flexible, center strand, orbital, chain conveyor. The rear body section has a load-carrying compartment above the conveyor and has upstanding push blades on opposite sides of the conveyor with power cylinders to move the blades inwardly and to transfer material onto the conveyor during unloading. Use of the vehicle is characterized by one-direction movement of load by the conveyor so it is never necessary to turn the vehicle around while transferring material from a mine face to a remote discharge location, and movement around tight corners is facilitated by the relative horizontal swinging movement between the two body sections.
Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function.
[ "BACKGROUND OF THE INVENTION This invention belongs to the field of material haulage vehicles and more particularly to improvements in the type commonly known as "shuttle cars"", "for hauling loose mined material in underground mines.", "Shuttle cars must operate in mine rooms and entries where the bottom and the top undulate, where height and space restrictions are severe, and where turning radiuses are tight.", "Yet they must provide large capacity along with rapid loading, carrying, and unloading of mined material in great tonnages.", "As shown for example in Russell U.S. Pat. No. 2,962,176, vertically articulated shuttle cars have been developed for low height, undulating passages.", "As the contour of the floor changes, fore and aft body sections pivot about a horizontal axis to prevent the underside or topside of the car from hanging up on the floor or roof.", "However, in many mines it would be physically impossible for shuttle cars of adequate capacity to make the tight turns encountered without "brushing"", "the corners, i.e. blasting them off to eliminate the sharp turns.", "This, of course, is wasteful of labor and energy and could be avoided if shuttle cars could articulate horizontally to avoid the sharp corners, as shown in FIG. 16.", "Attempts have been made to provide horizontal articulation in a mine haulage vehicle by using ejector scoops and shovel loaders.", "Examples are shown in U.S. Pat. No. 3,937,345 and the following equipment advertisements in the April 1976 Coal Age: pages 58 and 59, showing ejector buckets manufactured by Wagner Mining Equipment Co.;", "page 166, an ejector bucket manufactured by Fairchild Inc.;", "page 173, a scoop manufactured by Owens Mfg.", "Inc.;", "page 196, ram cars manufactured by Dresser Industries;", "page 205, a scoop/tractor manufactured by Pyott-Boone, Inc.;", "page 268, an ejector scoop manufactured by S &", "S Corporation;", "and pages 374, 375, an ejector scoop manufactured by Eimco Mining Machinery.", "Although these units have a tractor section and a cargo section pivotally interconnected for horizontal swinging movement, they have a very serious drawback in that loading and unloading must both be done from the scoop or shovel end, requiring the machine to make two full 180° turns on each trip between the loading and unloading sites.", "This takes time and often requires brushing out a turn-around area which otherwise would be unnecessary.", "There is a need for a horizontally articulated mine haulage vehicle which can receive a load at one end, convey it in one direction through the vehicle, and discharge it from the other end without turning the vehicle around.", "SUMMARY OF THE INVENTION It is therefore the major object of the present invention to provide an improved shuttle car with articulating pivot means enabling relative horizontal swinging movement between adjacent main body sections, and a horizontally flexible, orbitally movable conveyor means extending through the vehicle.", "Another object of the present invention is to provide a mine haulage vehicle having an elongated body with a front outbye section and a rear inbye section which are interconnected at adjacent ends by vertical pivot means to enable the body sections to swing freely horizontally, relative to each other.", "The vehicle has a horizontally flexible centerstrand chain conveyor, orbitally movable about sprockets at opposite ends, the conveyor having an upper-load-carrying run, movable along the bottom of a cargo-carrying compartment in the inbye section and discharging from the front end of the outbye section, to provide one-direction loading and unloading while enabling the body to swing horizontally so it can negotiate sharp turns.", "Another object is to provide a haulage vehicle as described in which the outbye section has an elevatable boom for the conveyor, enabling it to discharge into an elevated conveyor or mine car.", "Another object is to provide a horizontally-articulated vehicle as described in which the pivot means includes vertically-spaced upper and lower horizontal rear portions of the front body section, pivotally connected respectively to vertically-spaced upper and lower horizontal front portions of the rear body section, the carrying reach of the conveyor being movable across the top of the pivotally-connected upper horizontal portions of the two sections, and the return reach of the conveyor being movable through the space between the pivotally-connected upper and lower horizontal portions of the two sections, thereby enabling the longitudinal axis of the conveyor to intersect the pivotal axis between the body sections while permitting horizontal articulation of the vehicle and straight-through transfer of material between the cargo-carrying compartment and the discharge end.", "Another object is to provide a mine haulage vehicle as described in which a pair of vertical push blades are provided on opposite sides of the conveyor in the cargo compartment.", "Another object is to support one of the body sections by wheels on opposite sides, each of the wheels being supported on a separate subframe independently of the other wheel, each subframe being pivotally mounted and tiltable against springs to provide a flexible suspension for the vehicle.", "Other objects and advantages will be apparent from the following description taken in connection with the accompanying drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are plan and side views respectively of a mine haulage vehicle illustrating one form of the present invention, FIG. 1 being shown in two sections, FIGS. 1A and 1B, and FIG. 2 being shown in two sections, FIGS. 2A and 2B;", "FIG. 3 is an enlarged fragmentary view of FIG. 1A;", "FIG. 4 is a combined vertical sectional and rear view of FIG. 1B taken generally in the direction of the arrows 4--4;", "FIG. 5 is an enlarged fragmentary cross-sectional view of FIG. 1A taken along line 5--5;", "FIG. 6 is an enlarged top plan view of one of the wheel assemblies shown in FIG. 1A;", "FIG. 7 is a partially cut-away side view of FIG. 6;", "FIG. 8 is a top plan view of the discharge boom;", "FIG. 9 is a side view of FIG. 8;", "FIG. 10 is a top plan view of the front, outbye body section;", "FIG. 11 is a side view of FIG. 10;", "FIG. 12 is a fragmentary cross-sectional view of FIG. 11 taken along line 12--12, together with an associated portion of one of the wheel-supporting subframes;", "FIG. 13 is a top plan view of the rear, inbye cargo-carrying body section;", "FIG. 14 is a side view of FIG. 13;", "FIG. 15 is a fragmentary view of FIG. 7 taken along line 15--15;", "FIG. 16 is a top plan view of the mine haulage vehicle in an articulated condition, as it makes a turn around a sharp corner in a mine;", "and FIG. 17 is a side view of the vehicle with its discharge boom in a raised position for elevated load discharge onto a conveyor.", "Like parts are referred to by like reference characters.", "DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the specific embodiment of the invention in the drawings, and particularly to FIGS. 1, 2 and 16, the mine haulage vehicle is generally designated 20.", "It comprises an elongated body having a front or outbye section 22 and a rear or inbye section 24, the front section having an elevatable discharge boom 26.", "The vehicle is supported on pairs of individually self-powered front and rear wheel assemblies 28 and 30 respectively.", "The body sections are interconnected at adjacent ends by pivot means generally designated 32 enabling them to swing freely horizontally relative to each other about a vertical pivot axis 34;", "this enables steering the vehicle in a manner to clear corners as shown in FIG. 16.", "An orbitally movable, horizontally flexible, center strand chain flight conveyor 36 is trained between a front drive sprocket 38 and a rear idler sprocket 40.", "The above basic components will now be described in more detail.", "The frame of the rear body section 24 has a central, horizontal, longitudinally extending plate 42 for guiding the conveying run of the conveyor 36.", "An inclined plate section 46 guides the conveying run upward to a forwardly extending fan-shaped plate 48, the latter having a circularly extending leading edge 50 centered at axis 34.", "Channel members 54 (FIG.", "4) are affixed as by welding to opposite edges of the plate 42, providing guidance and support for both the conveying run 44 and return run 45 of the conveyor 36.", "The conveyor comprises a conventional center chain 56 with flights 58.", "Universal connecting links 60 enable the chain to flex vertically about the sprockets 38, 40, and horizontally when the two body sections are articulated about the axis 34.", "The channel members 54 have upper inwardly extending flanges 62, functioning as hold-downs for the ends of the flights 58, and lower inwardly extending flanges 64 supporting the flights in the return run.", "A load or cargo compartment 66 is provided in the inbye body section 24 and is defined by conveyor floor plates 42 and 68, side walls 70, 72, 74, 76, 77 and rear wall 78.", "In addition, the load or cargo-carrying compartment is defined by upwardly and outwardly flaring sideboard plates 80 and 82.", "A pair of push blades 84, 84, are provided on opposite sides of the conveyor at the rear end of the cargo compartment 66.", "This facilitates a complete transfer of material to the conveyor during unloading, from the bottom plates 68 of the cargo compartment.", "Each push blade is movable toward and away from the conveyor between solid and broken line positions shown in FIG. 1B by hydraulic piston means 86.", "This comprises an outer cylinder 88 having a flange 90 fastened to the blade 84 by bolts 92.", "The usual arrangement (not shown) of multiple telescopic cylinders and pistons are provided internally of the outer cylinder 88 to provide the required range of movement for the push blade.", "That internal arrangement includes an inner piston shaft 94 extending through sidewall 76 and fastened between ribs 96, 96.", "Suitable conventional hydraulic inner ports and passages (not shown) are provided enabling the piston and cylinder means 86 to move the blades 84 reversibly between operative positions shown.", "Curved, vertical, forwardly diverging side plates 98, 98 are fastened as by welding to the margins of the fan-shaped plate 48, extending up to the circular edge 50.", "Conventional spring sideplates 100, 100 are fastened as by welding or bolting at their rear ends 102 to the forward ends of the conveyor through sidewalls 104.", "As best shown in FIGS. 5 and 14, a lower level conveyor guide plate 106 extends forwardly from the rear body section 24 immediately below the plate 48.", "Each wheel assembly 30 includes a rubber-tired wheel rotatively journaled in a gear box 108, which is fastened to the adjacent sidewall 72.", "An electric tram motor 110 is mounted on the adjacent sidewall 112 and is connected via drive shaft 114 and universal couplings 116 and 117 to drive the wheel 107 through the gear box.", "The rotor 118 for a disc brake is driven by the motor.", "It is located immediately adjacent the coupling 116.", "The brake comprises no part of the present invention so the caliper pads and other components are not shown.", "Each of the tram motors 110 may be energized by electric conductors and controls forming no part of the present invention and therefore are not shown.", "At the rear end of body section 24, the rear idler sprocket 40 is mounted on a cross-shaft 120, the ends of which are journaled within bearing boxes 122 which are guided for fore and aft adjustment movement along channel members 54.", "A slot (not shown) is provided in each channel member to enable such fore and aft movement and the center chain 56 is tensioned by a pair of springs 124 acting between the journal boxes 122 and brackets 126.", "If desired, suitable conventional means (not shown) may be employed to vary the compression of the spring and therefore the tension in the conveyor chain.", "The front, outbye body section 22 has a box-type central portion best shown in FIGS. 1A, 5, 10 and 11 consisting of upper and lower floor plates 128 and 130 and sidewalls 132, 132.", "The top surfaces of these floor plates are level respectively with the top surfaces of floor plates 48 and 106 to provide uninterrupted support for the upper and lower runs of the conveyor.", "The rear edges 134, 134a of these plates are curved to conform to the circularly extending leading edges 50, 50a of plates 48 and 106.", "An important feature of the present invention is the extremely heavy-duty construction of the pivot means 32 which provides the horizontally swingable connection between the front and rear body sections and enables the conveyor upper and lower runs to operate through the pivot axis 34 at all angular positions, up to at least 45° in either direction.", "Heavy crossbars 138, 138a are welded beneath the plates 128, 130 and they have similarly heavy rear plate extensions 140, 140a welded thereon.", "Steel gussets 143 welded beneath the plate 140 furnish supplemental support.", "The plates are counterbored as at 142, 142a for vertically-spaced bearing elements now to be described.", "Refer to FIG. 5. A ball- or roller-type turntable side and thrust bearing 144 has an outer race 146 and an inner race 148.", "Each outer race 146 is held in the counterbore 142 or 142a by means of cap bolts 150 which are threaded into the extensions 140, 140a.", "The inner races 148 are seated within counterbores 152, 152a in two circular retainer members 154 and 156.", "These are identical except for the apertures provided for the cap bolt fasteners 158 and 160, which, as shown in FIG. 5, are arranged respectively head up and head down.", "To illustrate the size of the bearing components required, the bearing balls 162 are 1 inch in diameter and are arranged on a pitch diameter of 18.875".", "The outer diameter of the outer race and the inner diameter of the inner race are respectively 22.5"", "and 15.5"", "respectively.", "There are twenty-four cap bolts 158 with their heads seated within counterbores 164 in the top plate 48.", "They extend through bores 166 in the inner race, and at their opposite ends are screwed into threaded bores 168 in the member 154.", "The heads of cap bolts 160 are seated within counterbores 170 in the underside of retainer disc 156.", "They extend upward through the bores 166 in the inner race 148 and are screw-connected into threaded openings 172 in plate 106.", "As best shown in FIGS. 1A and 5, a small retainer tab 174 is fastened to the top edge of each sidewall 132 and is spaced inwardly to provide sliding clearance for the flexible spring sideplates 100.", "These slide between the walls 132 and tabs 174 when the body sections are swung relative to one another.", "The lower floor plate 130 of the front body section 22 supports the conveyor return run 45.", "The forward portion of the body section 22 has a wide bottom frame plate 178 upon which various other compartments and components are supported.", "A pair of vertical frame plates 180 are spaced apart sufficiently that the discharge boom 26 will fit between them.", "The rear ends of the plates 180 and the forward ends of the sidewalls 132 are separated by means of spacers 182 (FIG.", "10) providing room between them for the rearward ends of the sidewalls 184 of the discharge boom.", "Separate, aligned pivot stub shafts 186 are supported between the overlapping portions of the members 132 and 180.", "These fit within the pivot openings 188 (FIG.", "9) in the discharge boom sidewalls enabling the latter to be tilted up and down about a tilt axis 190 (FIGS.", "8 and 10).", "To further strengthen the frame of front body section 22, a vertical reinforcing plate 192 is welded along each side edge of frame plate 178, and a vertical plate 194 is welded along the forward edge just beneath the conveyor and providing a mounting for elevating cylinder 196.", "The front body section 22 has a number of other components which are individually conventional in the field of mining machinery and shuttle cars, so they will not be described in detail.", "Briefly however these include a pair of electric tram motors 198 fixedly mounted on the outsides of vertical plates 192 by brackets 200 and 202.", "An electric motor starter box 204 is provided for the four motors.", "An electric motor 206 is connected to drive a hydraulic pump 208 which supplies the various hydraulic oil pressure requirements for the vehicle.", "A cable reel drum 210 is mounted within a cable reel compartment 212 and is driven by a small hydraulic motor 214.", "A spooler 216 controls the laying of cable (not shown) on the drum, the cable supplying the electric power requirements of the various electrically driven components.", "An operator's compartment 218 contains the usual facilities, not shown, enabling an operator to sit inside, under a protective steel canopy, and tram the shuttle car in either direction, steer it, and operate the various movable components.", "The elevatable boom 26 has upper and lower guide plates 220 and 222 for the upper and lower runs of the conveyor.", "A conveyor motor 224 drives the drive sprocket 38 through a gear reducer 226, both the motor and reducer being fixed on the side of the discharge boom as shown.", "The elevating cylinder 196 is pivotally connected at opposite ends to the brackets 228 on the front body section and brackets 230 on the underside of the boom to tilt the latter up and down about the axis 190 when the cylinder is actuated.", "The flexible supports for the front wheel assemblies 28 will now be described.", "Refer first to FIGS. 6, 7, 12 and 15.", "Each wheel assembly 28 comprises a sub-frame 231 consisting of a main vertical plate 232, a horizontal base plate 234, a vertical front end plate 236, and vertical ribs 238, 240 and 242.", "A rubber-tired wheel 244 is rotatably supported on a gear reducer 246 which, in turn, is mounted by flange 248 and bolts 250 on the main plate 232.", "Each wheel is driven by one of the tram motors 198 through universal joints 252, 254 and the above-mentioned reducer 246.", "Each sub-frame 231 has its rear end portion pivoted for up and down movement about an axis 256.", "The forward end portion is free to move against the compression of springs 258.", "The latter are retained at their bottoms within cup-like seats 260.", "The upper ends of springs 258 are seated within downwardly facing cup-like seats similar to those designated 260, in an adjustment bar 262.", "A pair of adjusting bolts 264 are threadedly engaged through a mounting block 266 strengthened by gibs 267.", "The bottoms of these ajusting bolts bear against the top side of the adjustment bar 262.", "Rotation of the screws 264, therefore, adjust the level of the front end of the machine.", "As shown in FIGS. 6, 7 and 15, the sub-frame 231 is journaled for up and down rocking movement on a post 268 affixed as by welding to the vertical plate 192 and stiffened by a steel gusset 269.", "A cylindrical shaft portion 270 is journaled within a sleeve bearing 272 which, in turn, is retained within a split bearing block 274, the two halves of which are held together by socket head cap screws 276 and 278.", "A nut 275 threaded to the end of each shaft 268 holds the corresponding sub-frame 231 assembled.", "At the front, tiltable, end of the sub-frame 231, it is guided against excessive transverse movement by a slide block 280 attached to it as by welding.", "As shown in FIGS. 7 and 12, this fits between vertical guides 282 which are welded to the back wall of the starter box 204.", "A pair of steering cylinders 284 are pivotally connected between mounts 286 and 288 on the rear and front body sections respectively.", "To simplify the drawings and description, inlet and outlet ports and interconnecting tubing and control valves have purposely been omitted from the hydraulic components because the operation of these components will be obvious to any person skilled in the art.", "Briefly, however, the boom elevating cylinder 196 may be either a single-acting cylinder or a double-acting cylinder, preferably the latter.", "The reel hydraulic motor 214 will preferably be reversible.", "The steering cylinders 284 must be reversible to steer in both directions and will be interconnected so that pressure will be applied concurrently to the head end of one and the rod end of the other so that they both cooperate in the steering action in both directions.", "In use, the mine haulage vehicle 20 will be positioned just outbye of a mining machine working at a face, with the cargo compartment 66 in position to receive coal or other mined material from the rear boom of the mining machine.", "In this position both the hydraulic piston and cylinder means 86 will be contracted to their maximum thereby drawing the push blades 84 outward against the sidewalls 76.", "As the compartment is loaded, the operator will periodically enerqize the conveyor motor 224 to move the conveyor and thereby fill the vehicle for its full length.", "When the vehicle is thus completely filled from one end to the other and mounded up to the extent permitted by head room in the mine, the operator in compartment 218 trams it in an outbye direction to a transfer point, usually a fixed rubber belt or mine car.", "A typical intersection in an underground mine is shown in FIG. 16 where the haulage vehicle is shown horizontally articulated (through the action of steering cylinders 284) enabling it to negotiate the sharp turns.", "It is obvious by inspection of FIG. 16 that it is only the result of the horizontal articulation of the two body sections about the pivot means 32 that this vehicle can operate in such tight quarters.", "When the vehicle reaches the main haulage conveyor 290 as shown in FIG. 17, cylinder 196 will be actuated to elevate the discharge boom over the conveyor, as shown.", "The above described arrangement is illustrative of a small number of many possible specific embodiments of this invention.", "Other arrangements can readily be devised in accordance with the principles disclosed by those skilled in the art without departing from the spirit and scope of the invention." ]
[0001] This application is a national stage completion of PCT/DE2010/050038 filed Jun. 17, 2010, which claims priority from German Application Serial No. 10 2009 027 036.1 filed Jun. 19, 2009. FIELD OF THE INVENTION [0002] The invention concerns a coupling lock for a trailer coupling, with a receptacle in which a coupling element is or can be inserted and an angle measuring device connected with the receptacle, by means of which rotation of the receptacle relative to the coupling element about a rotational axis is or can be detected. BACKGROUND OF THE INVENTION [0003] A trailer coupling for a tractor/trailer combination as a rule comprises a coupling lock with a receptacle in which a coupling element can be inserted. The coupling lock and the coupling element form an articulated joint so that the tractor vehicle can pivot relative to the trailer vehicle, for example when the combination has to drive round a curve. In this case the coupling lock is fixed on one vehicle of the combination and the coupling element on the other vehicle thereof. If the tractor vehicle is a passenger automobile, then as a rule the coupling element is attached to the tractor vehicle and comprises a ball head, which engages in the receptacle of the coupling lock in the form of a ball socket, fixed on the towbar of the trailer vehicle. Until now no system that is sufficiently well developed for mass production has been available for sensing the pivot angle between the coupling element and the coupling lock, which is also referred to as the combination angle. In attempts to stabilize the combination, the combination angle is determined, for example, with an arrangement of cable potentiometers. These or other length measurement sensors (ultrasonic, laser, radar) measure the distance between the rear bumper of the tractor vehicle and a suitable front surface of the trailer vehicle. The distance is off-center relative to the vehicle and varies as a function of the combination angle. The translation length variation of the distance is converted by a computer into a rotational angle signal. The disadvantage of this is that owing to measuring equipment of this type the coupling and decoupling of the trailer vehicle is no longer possible, or much more difficult, since the measuring equipment comprises part-systems on both the tractor vehicle and the trailer, which are sometimes even connected together mechanically. Moreover, such measuring equipment is as a rule not suitable for operation under adverse environmental conditions (humidity, temperatures). SUMMARY OF THE INVENTION [0004] Starting from there, the purpose of the present invention is to further develop the coupling lock previously mentioned, in such manner that coupling and decoupling can be carried out simply. [0005] The coupling lock according to the invention for a trailer coupling comprises a receptacle into which a coupling element is or can be inserted, an angle measuring device that is connected to the receptacle by means of which rotation of the receptacle relative to the coupling element about a rotational axis is or can be detected, and a magnetically adhering body elastically connected to the receptacle which, particularly in the coupled condition, adheres or can adhere magnetically to the coupling element and actuates or can actuate the angle measuring device. [0006] In the coupled condition, i.e. in a condition when the coupling element is inserted into the receptacle, the adhering body adheres magnetically to the coupling element preferably in such manner that it transmits rotation of the coupling element relative to the receptacle about the rotational axis to the angle measuring device and/or to an actuating element of the angle measuring device, thereby actuating it. Thus, the angle measuring device can detect the rotation and pass it on to an evaluation unit, the rotation detected preferably being passed on to the evaluation unit in the form of one or more electric signals. [0007] Preferably, when coupling takes place the connection between the magnetically adhering body and the coupling element is formed automatically by virtue of the magnetic attraction between the adhering body and the coupling element. In contrast, on decoupling the adhering body is preferably pulled away automatically from the coupling element. Thus, coupling and decoupling can be carried out relatively simply. Moreover, compared with a conventional coupling element the coupling element can preferably remain unchanged. [0008] ‘Coupling onto’ and/or just ‘coupling’ are understood to mean that the coupling element is brought into engagement with the receptacle, in particular inserted into it. ‘Decoupling’ is understood to mean that the coupling element is brought out of engagement with the receptacle, in particular removed therefrom. [0009] In the coupled condition the magnetically adhering body sticks magnetically to the coupling element, in particular firmly enough for a rotationally fixed and/or solid body-to-body connection to form, or to be able to form, between the adhering body and the coupling element. This rotationally fixed connection is preferably a frictional connection, the force needed for the connection being brought to bear as a magnetic force by the magnetically adhering body. Since on account of uneven road conditions movements between the coupling element and the receptacle other than the rotation about the rotational axis can also take place, the magnetically adhering body is connected elastically to the receptacle. However, compared with the maximum rotation that takes place about the rotational axis, these other movements are relatively small. [0010] The coupling element preferably consists of magnetic material, at least in the area where the magnetically adhering body sticks or can stick magnetically to the coupling element. [0011] The rotational axis is preferably a vertical axis, in particular one extending in the direction of the vertical axis of the trailer vehicle and/or the tractor vehicle. [0012] The elastic connection between the receptacle and the magnetically adhering body is preferably in the form of a holder, preferably an elastic holding fixture which, in particular, is elastic in the direction of the rotational axis. By virtue of the holder the magnetically adhering body is preferably held on the receptacle so that it can rotate about the rotational axis. [0013] The holder preferably comprises a rotary bearing which holds the magnetically adhering body, allowing it to rotate, and/or preferably an elastic element, for example made of rubber or plastic, and/or in the form of a spring. Preferably, the rotary bearing is connected elastically to the receptacle by means of the elastic element. The elastic element is for example in the form of a bellows. [0014] According to one design of the invention the rotary bearing comprises a bearing portion connected in a fixed manner, in particular materially-bonded with the elastic element, and a carrier mounted on the bearing and able to rotate about the rotational axis, which preferably carries the magnetically adhering body. The magnetically adhering body is preferably connected in a fixed manner, in particular solidly, to the carrier. To prevent the bearing portion and the carrier from moving out of engagement the carrier is secured, in particular axially, on the bearing portion. Here the term ‘axial’ means in particular the direction of the rotational axis. Preferably, the rotary bearing is a slide bearing. [0015] The bearing portion preferably comprises a sleeve in which the carrier is preferably seated. In particular, the sleeve is a sliding sleeve or sliding bush, preferably of cylindrical form. Preferably, the sleeve has at least one radial projection which engages in a ring-shaped or partially ring-shaped recess of the carrier. In this case ‘radial’ means a direction perpendicular to the rotational axis. A plurality of radial projections can be provided on the sleeve around the rotational axis, which engage in the recess. Preferably however, the radial projection is ring-shaped. In particular, the radial projection is a projection extending inward. The sleeve consists for example of metal or plastic. [0016] The angle measuring device preferably comprises a rotational angle sensor which is or can be actuated by the actuating element. The rotational angle sensor is preferably connected in a fixed manner, in particular solidly to the receptacle. Furthermore the actuating element is preferably connected fixed, in particular solidly to the magnetically adhering body. [0017] In a further development of the invention, the angle measuring device comprises a measuring magnet preferably connected in a fixed manner and in particular solidly to the carrier, and a magnetic field sensor preferably connected fixed and in particular solidly to the receptacle, such that the field from the measuring magnet passes or can pass through the magnetic field sensor. The magnetic field sensor forms in particular the rotational angle sensor and the measuring magnet forms in particular the actuating element. However a converse arrangement is also possible, such that alternatively the angle measuring device comprises a measuring magnet preferably connected fixed and in particular solidly to the receptacle and a magnetic field sensor preferably connected fixed and in particular solidly to the carrier, through which the magnetic field from the measuring magnet passes or can pass. [0018] In the coupled condition, rotation of the coupling element relative to the receptacle about the rotational axis causes the measuring magnet to rotate relative to the magnetic field sensor, in particular about the rotational axis, and this results in a variation of the magnetic field produced by the measuring magnet at the location of the magnetic field sensor. This change in magnetic field can be detected by the magnetic field sensor. In particular the measuring magnet is magnetized transversely to the rotational axis so that the change in magnetic field caused at the location of the magnetic field sensor by rotation is particularly clear. Preferably, the measuring magnet and the magnetic field sensor are arranged a distance apart along the rotational axis. A suitable magnetic field sensor is known, for example, from the documents EP 0 947 846 B1 and EP 1 182 461 A2. [0019] So that the carrier interferes as little as possible with the magnetic field of the measuring magnet, the carrier is preferably made entirely or partially of a non-magnetic material. For example, the carrier consists of plastic, aluminum, magnesium or non-ferromagnetic steel. In such a case the measuring magnet can be attached directly on the carrier. Alternatively, the measuring magnet is attached to the carrier with interposition of a non-magnetic material such as plastic. In that case the carrier can even be made of a magnetic material. The measuring magnet is preferably a permanent magnet, but can also be an electromagnet. [0020] So that the magnetic adhesion of the magnetically adhering body to the coupling element will be as firm as possible, the magnetically adhering body is orientated with one of its poles or with both poles toward the coupling element. The magnetically adhering body comprises an adhering magnet which is in particular a permanent magnet, but which can alternatively also be an electromagnet. In particular, the adhering magnet is magnetized in the direction of the rotational axis. [0021] According to a preferred further development of the invention, the magnetically adhering body is made of a magnetic material in the form of a pot, which is open toward the coupling element and in which the adhering magnet sits. This makes it possible, by virtue of the pot rim that delimits the pot's opening, also to direct the pole of the adhering magnet that faces away from the coupling element toward the coupling element. Thereby, magnetic attraction of the magnetically adhering body to the coupling element is strengthened. The bottom of the pot is preferably in direct contact with the pole of the adhering magnet that faces away from the coupling element. Between the adhering magnet and the wall of the pot that surrounds it, a gap is preferably left, in particular an air gap, but which can also be entirely or partially filled with a non-magnetic material. This gap is in particular annular. The pot is preferably made of steel. The adhering magnet cannot rest directly against the coupling element. Preferably, however, the adhering magnet is set back relative to the pot rim that delimits the pot's opening, particularly with its pole facing toward the coupling element, so that the adhering magnet itself does not or cannot come directly in contact with the coupling element. This protects the adhering magnet against mechanical loads. In contrast the rim of the pot that delimits its opening preferably rests directly against the coupling element. The pot is preferably connected in a fixed manner and in particular solidly to the carrier. [0022] The term ‘magnet material’ means any magnetic material. In particular, the term ‘magnet material’ means a ferromagnetic material. However, for example a ferrimagnetic material can also be used as the magnet material. [0023] The coupling element is or can be inserted into the receptacle, in particular so that it can rotate about the rotational axis. Preferably, the coupling element is or can be inserted into the receptacle so that it can also pivot about at least one pivot axis that extends transverse to the rotational axis. [0024] In a further development of the invention the coupling element has a ball head and the receptacle has a ball socket into which the ball head is or can be fitted. In particular, the ball head is or can be fitted into the ball socket in an articulated manner, so that the ball head and the ball socket form a spherical joint. Thus, the coupling lock according to the invention can be used together with a commonly available ball head for a trailer coupling for a passenger car. The ball head preferably has a diameter of 50 mm. Moreover, at its end pointing toward the ball socket, which is usually the top end of the ball head, the ball head preferably has a flat area against which the magnetically adhering body rests or can rest. This improves the magnetic connection between the magnetically adhering body and the ball head. In this context it is particularly advantageous that the flat area is as a rule already formed or commonly available ball heads. The ball head preferably consists of a magnetic material. [0025] The receptacle can be fixed onto a tractor vehicle and the coupling element onto a trailer vehicle. However, it is preferable for the receptacle to be fixed to a trailer vehicle, in particular to its tow bar, and for the coupling element to be fixed on a tractor vehicle, in particular to its chassis or body. The tractor vehicle is preferably a motor vehicle, in particular a passenger car. [0026] The angle measuring device is preferably connected electrically to an evaluation unit by means of which the rotational angle of the coupling element relative to the receptacle about the rotational axis can be determined. In particular, the bend angle of a combination consisting of the tractor vehicle and the trailer vehicle can be determined. Here, ‘bend angle’ is understood to mean, in particular, the angle between the longitudinal axis of the tractor vehicle and the longitudinal axis of the trailer vehicle, this bend angle lying, in particular, in a plane perpendicular to the rotational axis. For example if the longitudinal axis of the trailer vehicle lies in a plane perpendicular to the rotational axis, the bend angle is preferably the angle between the longitudinal axis of the trailer vehicle and the projection of the longitudinal axis of the tractor vehicle on the plane. The plane is as a rule parallel to the plane of the road. [0027] According to a design of the invention, a towbar-side measurement of the combination angle (bend angle) is thus possible when the angle measuring device is fixed in the coupling lock on the trailer side. The angle measuring device is fitted centrally over the ball holder (receptacle or ball socket). Among other things this arrangement has a magnetically adhering body on the underside of the angle measuring device, which is connected by an elastic plastic component to a housing of the angle measuring device fixed on the receptacle. When the coupling lock is coupled with the coupling element the magnetically adhering body is brought close to the ball head. By virtue of the magnetic force of the magnetically adhering body a connection is formed between it and the ball head, so that from then on the magnetically adhering body is held firmly onto the ball head. The ball head has a standardized flat area on which the magnetically adhering body can rest. Thus, relative rotation between the ball head and the coupling lock is transferred to the angle measuring device. There, this relative rotation, which is predominantly rotation about a vertical axis (rotational axis) through the ball head, is detected unequivocally by a rotational angle sensor in the coupling lock. In particular, this rotational angle sensor is a magnetic field sensor. The rotational angle is detected by the sensor and passed on in the form of an electrical signal to an evaluation unit for further processing. On decoupling, the magnetically adhering body together with the coupling lock are automatically pulled clear of the ball head. [0028] The invention provides the possibility of repetitive combination (bend) angle measurement. For example, the combination angle can be made available to systems for drive-dynamical stabilization of the combination and/or to driving assistance systems. Moreover, the vehicle's driver can be informed of the combination angle, for example by means of a display in the passenger compartment of the tractor vehicle. Bend angle fluctuations can also be detected, which can indicate an unstable condition of the combination (swinging). [0029] The invention also pertains to a trailer coupling with a coupling lock according to the invention, such that the magnetically adhering body sticks magnetically to the coupling element and actuates or can actuate the angle measuring device. [0030] Furthermore, the invention concerns the use of a coupling lock according to the invention for a trailer coupling between a tractor vehicle and a trailer vehicle, such that the magnetically adhering body sticks magnetically onto the coupling element and actuates the angle measuring device. In particular, from the rotation detected by the angle measuring device the bend angle between the longitudinal axis of the tractor vehicle and the longitudinal axis of the trailer vehicle is determined. BRIEF DESCRIPTION OF THE DRAWINGS [0031] Below, the invention is described with reference to a preferred embodiment illustrated in the drawings, which show: [0032] FIG. 1 : A top view of a combination consisting of a tractor vehicle and a trailer vehicle, and [0033] FIG. 2 : A sectional view through the trailer coupling shown in FIG. 1 , along the section line 2 - 2 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0034] FIG. 1 shows a top view of a combination 3 comprising a tractor vehicle 1 and a trailer vehicle 2 , in which the tractor vehicle 1 is articulated to the trailer vehicle 2 by means of a trailer coupling 4 . The normal forward driving direction of the tractor vehicle 1 and/or the combination 3 is indicated by the arrow 33 . The trailer coupling 4 comprises a coupling element 6 connected solidly to the chassis or vehicle body 5 of the tractor vehicle 1 and a coupling lock 8 fixed onto a towbar 7 of the trailer vehicle 2 . [0035] The coupling lock 8 comprises a ball socket 9 into which a schematically represented ball head 10 of the coupling element 6 is fitted, such that the ball head 10 forms an end of the coupling element 6 at the rear thereof in relation to the driving direction 33 . Furthermore, the coupling lock 8 forms a front end of the towbar 7 in the driving direction 33 . [0036] The angle a between the longitudinal axis 11 of the tractor vehicle 1 and the longitudinal axis 12 of the trailer vehicle 2 is the so-termed bend angle or combination angle. In particular, the bend angle a lies in a plane perpendicular to the vertical direction 34 of the trailer vehicle 2 , the vertical direction 34 relative to the vehicle in FIG. 1 being perpendicular to the plane of the drawing. [0037] FIG. 2 shows a sectional view through the trailer coupling 4 along the longitudinal axis 12 and in the vehicle's vertical direction 34 , wherein at the upper end of the ball socket 9 there is attached a magnetic field sensor 13 which is fixed by means of a housing 14 . To the housing 14 is attached an elastic bellows 15 , which supports a sliding sleeve 16 and is connected thereto in a materially-bonded manner. In the sliding sleeve 16 is fitted a carrier 17 which can rotate about a rotational axis 18 , and which carries at its upper end facing toward the sensor 13 a measuring magnet 19 in the form of a permanent magnet. The north and south poles of the measuring magnet 19 are indicated, in order to make clear that the magnetization direction of the measuring magnet 19 is transverse to the rotational axis 18 . The carrier 17 , which is made from a non-magnetic material, has an upper portion 20 and a lower portion 21 mounted on the latter, an annular groove 22 being enclosed between the upper portion 20 and the lower portion 21 , in which an annular, radially inward-extending projection 23 of the sliding sleeve 16 engages. Thus, the carrier 17 is secured onto the sliding sleeve 16 in the direction of the rotational axis 18 . The rotational axis 18 extends in the vehicle's vertical direction 34 and so constitutes a vertical axis. [0038] To the lower end of the carrier 17 facing toward the ball head 10 is fixed a magnetically adhering body 24 comprising a permanent magnet 25 and a pot 26 in which the magnet 25 sits. The north and south poles of the magnet 25 are indicated in order to make clear that it is magnetized in the direction of the rotational axis 18 . The pot 26 consists of a magnetic material, so that the south pole of the magnet 25 appears at the rim of the pot 26 facing toward the ball head 10 . Needless to say, the north and south poles can be exchanged. [0039] The edge of the pot 26 rests against a flat area 27 of the ball head 10 and is held firmly onto it by magnetic force, since the ball head 10 too is made of a magnetic material. It can be seen that the north pole of the magnet 25 is slightly set back relative to the lower rim of the pot, so that direct contact between the magnet 25 and the ball head 10 is prevented. Moreover, an annular air gap is left between the magnet 25 and the wall of the pot 26 that surrounds it. [0040] In addition the coupling lock 8 comprises a catch 28 that can be actuated, which is shown in the locked condition in FIG. 2 , so that the ball head 10 is held positively in the ball socket 9 . For decoupling, the catch 28 can be retracted so that the coupling lock 8 can be moved clear of the ball head 10 . In this event the magnetically adhering body 24 is also and at the same time separated from the ball head 10 . [0041] In the coupled condition of the trailer coupling 4 , if the ball head 10 rotates about the rotational axis 18 relative to the coupling lock 8 the magnetically adhering body 24 rotates together with the ball head 10 . Since the magnetically adhering body 24 is connected by means of the carrier 17 to the measuring magnet 19 in a rotationally fixed manner, the measuring magnet 19 too rotates with the ball head 10 about the rotational axis 18 . the rotation can be detected by the sensor 13 , which then emits an electrical signal 29 that characterizes the rotation to an evaluation unit 30 to which the sensor 13 is connected by electric leads 31 . On the basis of the electric signal 29 the bend angle a is determined by the evaluation unit 30 . [0042] According to a first alternative the evaluation unit 30 is located in the tractor vehicle 1 , so the lead 31 extends from the coupling lock 8 to the tractor vehicle 1 . In a second alternative the evaluation unit 30 is in the trailer vehicle 2 , which is coupled electrically by leads 32 to the tractor vehicle 1 . In the latter case the information about the bend angle a can be made available to the tractor vehicle 1 via the electric leads 32 . [0043] In a variant embodiment the communication between the sensor 13 and the evaluation unit 30 and/or between the evaluation unit 30 and the tractor vehicle 1 can take place by wireless means, for example by radio. [0044] If because of uneven road conditions movements occur between the coupling lock 8 and the ball head 10 which deviate from rotation about the rotational axis 18 , for example tilting movements between the tractor vehicle 1 and the trailer vehicle 2 , then such deviant movements are accommodated by the elastic bellows 15 so that the angle measuring device or the arrangement comprising the magnetic field sensor 13 , elastic bellows 15 , sliding sleeve 16 , carrier 17 , measuring magnet 19 and magnetically adhering body 24 is not damaged. LIST OF INDEXES [0000] 1 Tractor vehicle 2 Trailer vehicle 3 Combination 4 Trailer coupling 5 Chassis of the tractor vehicle 6 Coupling element 7 Towbar of the trailer vehicle 8 Coupling lock 9 Ball socket 10 Ball head 11 Longitudinal axis of the tractor vehicle 12 Longitudinal axis of the trailer vehicle 13 Magnetic field sensor 14 Housing of the magnetic field sensor 15 Elastic bellows 16 Sliding sleeve 17 Carrier 18 Rotational axis 19 Measuring magnet 20 Upper portion of the carrier 21 Lower portion of the carrier 22 Annular groove in the carrier 23 Radial projection in the sliding sleeve 24 Magnetically adhering body 25 Adhering magnet 26 Pot 27 Flat area 28 Catch 29 Signal from the magnetic field sensor 30 Evaluation unit 31 Electric connection lead 32 Electric connection lead 33 Driving direction 34 Vertical direction of the vehicle
A coupling lock for a trailer coupling. The coupling lock comprises a receptacle ( 9 ) in which a coupling element ( 6 ) is inserted, an angle measuring device ( 13, 19 ) is connected to the receptacle ( 9 ), and the angle measuring device ( 13, 19 ) is provided for detecting rotation of the receptacle ( 9 ), about a rotational axis ( 18 ), relative to the coupling element ( 6 ). A magnetically adhering body ( 24 ) is elastically connected to the receptacle ( 9 ) and magnetically connectable to the coupling element ( 6 ) for actuating the angle measuring device ( 13, 19 ).
Provide a concise summary of the essential information conveyed in the given context.
[ "[0001] This application is a national stage completion of PCT/DE2010/050038 filed Jun. 17, 2010, which claims priority from German Application Serial No. 10 2009 027 036.1 filed Jun. 19, 2009.", "FIELD OF THE INVENTION [0002] The invention concerns a coupling lock for a trailer coupling, with a receptacle in which a coupling element is or can be inserted and an angle measuring device connected with the receptacle, by means of which rotation of the receptacle relative to the coupling element about a rotational axis is or can be detected.", "BACKGROUND OF THE INVENTION [0003] A trailer coupling for a tractor/trailer combination as a rule comprises a coupling lock with a receptacle in which a coupling element can be inserted.", "The coupling lock and the coupling element form an articulated joint so that the tractor vehicle can pivot relative to the trailer vehicle, for example when the combination has to drive round a curve.", "In this case the coupling lock is fixed on one vehicle of the combination and the coupling element on the other vehicle thereof.", "If the tractor vehicle is a passenger automobile, then as a rule the coupling element is attached to the tractor vehicle and comprises a ball head, which engages in the receptacle of the coupling lock in the form of a ball socket, fixed on the towbar of the trailer vehicle.", "Until now no system that is sufficiently well developed for mass production has been available for sensing the pivot angle between the coupling element and the coupling lock, which is also referred to as the combination angle.", "In attempts to stabilize the combination, the combination angle is determined, for example, with an arrangement of cable potentiometers.", "These or other length measurement sensors (ultrasonic, laser, radar) measure the distance between the rear bumper of the tractor vehicle and a suitable front surface of the trailer vehicle.", "The distance is off-center relative to the vehicle and varies as a function of the combination angle.", "The translation length variation of the distance is converted by a computer into a rotational angle signal.", "The disadvantage of this is that owing to measuring equipment of this type the coupling and decoupling of the trailer vehicle is no longer possible, or much more difficult, since the measuring equipment comprises part-systems on both the tractor vehicle and the trailer, which are sometimes even connected together mechanically.", "Moreover, such measuring equipment is as a rule not suitable for operation under adverse environmental conditions (humidity, temperatures).", "SUMMARY OF THE INVENTION [0004] Starting from there, the purpose of the present invention is to further develop the coupling lock previously mentioned, in such manner that coupling and decoupling can be carried out simply.", "[0005] The coupling lock according to the invention for a trailer coupling comprises a receptacle into which a coupling element is or can be inserted, an angle measuring device that is connected to the receptacle by means of which rotation of the receptacle relative to the coupling element about a rotational axis is or can be detected, and a magnetically adhering body elastically connected to the receptacle which, particularly in the coupled condition, adheres or can adhere magnetically to the coupling element and actuates or can actuate the angle measuring device.", "[0006] In the coupled condition, i.e. in a condition when the coupling element is inserted into the receptacle, the adhering body adheres magnetically to the coupling element preferably in such manner that it transmits rotation of the coupling element relative to the receptacle about the rotational axis to the angle measuring device and/or to an actuating element of the angle measuring device, thereby actuating it.", "Thus, the angle measuring device can detect the rotation and pass it on to an evaluation unit, the rotation detected preferably being passed on to the evaluation unit in the form of one or more electric signals.", "[0007] Preferably, when coupling takes place the connection between the magnetically adhering body and the coupling element is formed automatically by virtue of the magnetic attraction between the adhering body and the coupling element.", "In contrast, on decoupling the adhering body is preferably pulled away automatically from the coupling element.", "Thus, coupling and decoupling can be carried out relatively simply.", "Moreover, compared with a conventional coupling element the coupling element can preferably remain unchanged.", "[0008] ‘Coupling onto’ and/or just ‘coupling’ are understood to mean that the coupling element is brought into engagement with the receptacle, in particular inserted into it.", "‘Decoupling’ is understood to mean that the coupling element is brought out of engagement with the receptacle, in particular removed therefrom.", "[0009] In the coupled condition the magnetically adhering body sticks magnetically to the coupling element, in particular firmly enough for a rotationally fixed and/or solid body-to-body connection to form, or to be able to form, between the adhering body and the coupling element.", "This rotationally fixed connection is preferably a frictional connection, the force needed for the connection being brought to bear as a magnetic force by the magnetically adhering body.", "Since on account of uneven road conditions movements between the coupling element and the receptacle other than the rotation about the rotational axis can also take place, the magnetically adhering body is connected elastically to the receptacle.", "However, compared with the maximum rotation that takes place about the rotational axis, these other movements are relatively small.", "[0010] The coupling element preferably consists of magnetic material, at least in the area where the magnetically adhering body sticks or can stick magnetically to the coupling element.", "[0011] The rotational axis is preferably a vertical axis, in particular one extending in the direction of the vertical axis of the trailer vehicle and/or the tractor vehicle.", "[0012] The elastic connection between the receptacle and the magnetically adhering body is preferably in the form of a holder, preferably an elastic holding fixture which, in particular, is elastic in the direction of the rotational axis.", "By virtue of the holder the magnetically adhering body is preferably held on the receptacle so that it can rotate about the rotational axis.", "[0013] The holder preferably comprises a rotary bearing which holds the magnetically adhering body, allowing it to rotate, and/or preferably an elastic element, for example made of rubber or plastic, and/or in the form of a spring.", "Preferably, the rotary bearing is connected elastically to the receptacle by means of the elastic element.", "The elastic element is for example in the form of a bellows.", "[0014] According to one design of the invention the rotary bearing comprises a bearing portion connected in a fixed manner, in particular materially-bonded with the elastic element, and a carrier mounted on the bearing and able to rotate about the rotational axis, which preferably carries the magnetically adhering body.", "The magnetically adhering body is preferably connected in a fixed manner, in particular solidly, to the carrier.", "To prevent the bearing portion and the carrier from moving out of engagement the carrier is secured, in particular axially, on the bearing portion.", "Here the term ‘axial’ means in particular the direction of the rotational axis.", "Preferably, the rotary bearing is a slide bearing.", "[0015] The bearing portion preferably comprises a sleeve in which the carrier is preferably seated.", "In particular, the sleeve is a sliding sleeve or sliding bush, preferably of cylindrical form.", "Preferably, the sleeve has at least one radial projection which engages in a ring-shaped or partially ring-shaped recess of the carrier.", "In this case ‘radial’ means a direction perpendicular to the rotational axis.", "A plurality of radial projections can be provided on the sleeve around the rotational axis, which engage in the recess.", "Preferably however, the radial projection is ring-shaped.", "In particular, the radial projection is a projection extending inward.", "The sleeve consists for example of metal or plastic.", "[0016] The angle measuring device preferably comprises a rotational angle sensor which is or can be actuated by the actuating element.", "The rotational angle sensor is preferably connected in a fixed manner, in particular solidly to the receptacle.", "Furthermore the actuating element is preferably connected fixed, in particular solidly to the magnetically adhering body.", "[0017] In a further development of the invention, the angle measuring device comprises a measuring magnet preferably connected in a fixed manner and in particular solidly to the carrier, and a magnetic field sensor preferably connected fixed and in particular solidly to the receptacle, such that the field from the measuring magnet passes or can pass through the magnetic field sensor.", "The magnetic field sensor forms in particular the rotational angle sensor and the measuring magnet forms in particular the actuating element.", "However a converse arrangement is also possible, such that alternatively the angle measuring device comprises a measuring magnet preferably connected fixed and in particular solidly to the receptacle and a magnetic field sensor preferably connected fixed and in particular solidly to the carrier, through which the magnetic field from the measuring magnet passes or can pass.", "[0018] In the coupled condition, rotation of the coupling element relative to the receptacle about the rotational axis causes the measuring magnet to rotate relative to the magnetic field sensor, in particular about the rotational axis, and this results in a variation of the magnetic field produced by the measuring magnet at the location of the magnetic field sensor.", "This change in magnetic field can be detected by the magnetic field sensor.", "In particular the measuring magnet is magnetized transversely to the rotational axis so that the change in magnetic field caused at the location of the magnetic field sensor by rotation is particularly clear.", "Preferably, the measuring magnet and the magnetic field sensor are arranged a distance apart along the rotational axis.", "A suitable magnetic field sensor is known, for example, from the documents EP 0 947 846 B1 and EP 1 182 461 A2.", "[0019] So that the carrier interferes as little as possible with the magnetic field of the measuring magnet, the carrier is preferably made entirely or partially of a non-magnetic material.", "For example, the carrier consists of plastic, aluminum, magnesium or non-ferromagnetic steel.", "In such a case the measuring magnet can be attached directly on the carrier.", "Alternatively, the measuring magnet is attached to the carrier with interposition of a non-magnetic material such as plastic.", "In that case the carrier can even be made of a magnetic material.", "The measuring magnet is preferably a permanent magnet, but can also be an electromagnet.", "[0020] So that the magnetic adhesion of the magnetically adhering body to the coupling element will be as firm as possible, the magnetically adhering body is orientated with one of its poles or with both poles toward the coupling element.", "The magnetically adhering body comprises an adhering magnet which is in particular a permanent magnet, but which can alternatively also be an electromagnet.", "In particular, the adhering magnet is magnetized in the direction of the rotational axis.", "[0021] According to a preferred further development of the invention, the magnetically adhering body is made of a magnetic material in the form of a pot, which is open toward the coupling element and in which the adhering magnet sits.", "This makes it possible, by virtue of the pot rim that delimits the pot's opening, also to direct the pole of the adhering magnet that faces away from the coupling element toward the coupling element.", "Thereby, magnetic attraction of the magnetically adhering body to the coupling element is strengthened.", "The bottom of the pot is preferably in direct contact with the pole of the adhering magnet that faces away from the coupling element.", "Between the adhering magnet and the wall of the pot that surrounds it, a gap is preferably left, in particular an air gap, but which can also be entirely or partially filled with a non-magnetic material.", "This gap is in particular annular.", "The pot is preferably made of steel.", "The adhering magnet cannot rest directly against the coupling element.", "Preferably, however, the adhering magnet is set back relative to the pot rim that delimits the pot's opening, particularly with its pole facing toward the coupling element, so that the adhering magnet itself does not or cannot come directly in contact with the coupling element.", "This protects the adhering magnet against mechanical loads.", "In contrast the rim of the pot that delimits its opening preferably rests directly against the coupling element.", "The pot is preferably connected in a fixed manner and in particular solidly to the carrier.", "[0022] The term ‘magnet material’ means any magnetic material.", "In particular, the term ‘magnet material’ means a ferromagnetic material.", "However, for example a ferrimagnetic material can also be used as the magnet material.", "[0023] The coupling element is or can be inserted into the receptacle, in particular so that it can rotate about the rotational axis.", "Preferably, the coupling element is or can be inserted into the receptacle so that it can also pivot about at least one pivot axis that extends transverse to the rotational axis.", "[0024] In a further development of the invention the coupling element has a ball head and the receptacle has a ball socket into which the ball head is or can be fitted.", "In particular, the ball head is or can be fitted into the ball socket in an articulated manner, so that the ball head and the ball socket form a spherical joint.", "Thus, the coupling lock according to the invention can be used together with a commonly available ball head for a trailer coupling for a passenger car.", "The ball head preferably has a diameter of 50 mm.", "Moreover, at its end pointing toward the ball socket, which is usually the top end of the ball head, the ball head preferably has a flat area against which the magnetically adhering body rests or can rest.", "This improves the magnetic connection between the magnetically adhering body and the ball head.", "In this context it is particularly advantageous that the flat area is as a rule already formed or commonly available ball heads.", "The ball head preferably consists of a magnetic material.", "[0025] The receptacle can be fixed onto a tractor vehicle and the coupling element onto a trailer vehicle.", "However, it is preferable for the receptacle to be fixed to a trailer vehicle, in particular to its tow bar, and for the coupling element to be fixed on a tractor vehicle, in particular to its chassis or body.", "The tractor vehicle is preferably a motor vehicle, in particular a passenger car.", "[0026] The angle measuring device is preferably connected electrically to an evaluation unit by means of which the rotational angle of the coupling element relative to the receptacle about the rotational axis can be determined.", "In particular, the bend angle of a combination consisting of the tractor vehicle and the trailer vehicle can be determined.", "Here, ‘bend angle’ is understood to mean, in particular, the angle between the longitudinal axis of the tractor vehicle and the longitudinal axis of the trailer vehicle, this bend angle lying, in particular, in a plane perpendicular to the rotational axis.", "For example if the longitudinal axis of the trailer vehicle lies in a plane perpendicular to the rotational axis, the bend angle is preferably the angle between the longitudinal axis of the trailer vehicle and the projection of the longitudinal axis of the tractor vehicle on the plane.", "The plane is as a rule parallel to the plane of the road.", "[0027] According to a design of the invention, a towbar-side measurement of the combination angle (bend angle) is thus possible when the angle measuring device is fixed in the coupling lock on the trailer side.", "The angle measuring device is fitted centrally over the ball holder (receptacle or ball socket).", "Among other things this arrangement has a magnetically adhering body on the underside of the angle measuring device, which is connected by an elastic plastic component to a housing of the angle measuring device fixed on the receptacle.", "When the coupling lock is coupled with the coupling element the magnetically adhering body is brought close to the ball head.", "By virtue of the magnetic force of the magnetically adhering body a connection is formed between it and the ball head, so that from then on the magnetically adhering body is held firmly onto the ball head.", "The ball head has a standardized flat area on which the magnetically adhering body can rest.", "Thus, relative rotation between the ball head and the coupling lock is transferred to the angle measuring device.", "There, this relative rotation, which is predominantly rotation about a vertical axis (rotational axis) through the ball head, is detected unequivocally by a rotational angle sensor in the coupling lock.", "In particular, this rotational angle sensor is a magnetic field sensor.", "The rotational angle is detected by the sensor and passed on in the form of an electrical signal to an evaluation unit for further processing.", "On decoupling, the magnetically adhering body together with the coupling lock are automatically pulled clear of the ball head.", "[0028] The invention provides the possibility of repetitive combination (bend) angle measurement.", "For example, the combination angle can be made available to systems for drive-dynamical stabilization of the combination and/or to driving assistance systems.", "Moreover, the vehicle's driver can be informed of the combination angle, for example by means of a display in the passenger compartment of the tractor vehicle.", "Bend angle fluctuations can also be detected, which can indicate an unstable condition of the combination (swinging).", "[0029] The invention also pertains to a trailer coupling with a coupling lock according to the invention, such that the magnetically adhering body sticks magnetically to the coupling element and actuates or can actuate the angle measuring device.", "[0030] Furthermore, the invention concerns the use of a coupling lock according to the invention for a trailer coupling between a tractor vehicle and a trailer vehicle, such that the magnetically adhering body sticks magnetically onto the coupling element and actuates the angle measuring device.", "In particular, from the rotation detected by the angle measuring device the bend angle between the longitudinal axis of the tractor vehicle and the longitudinal axis of the trailer vehicle is determined.", "BRIEF DESCRIPTION OF THE DRAWINGS [0031] Below, the invention is described with reference to a preferred embodiment illustrated in the drawings, which show: [0032] FIG. 1 : A top view of a combination consisting of a tractor vehicle and a trailer vehicle, and [0033] FIG. 2 : A sectional view through the trailer coupling shown in FIG. 1 , along the section line 2 - 2 .", "DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0034] FIG. 1 shows a top view of a combination 3 comprising a tractor vehicle 1 and a trailer vehicle 2 , in which the tractor vehicle 1 is articulated to the trailer vehicle 2 by means of a trailer coupling 4 .", "The normal forward driving direction of the tractor vehicle 1 and/or the combination 3 is indicated by the arrow 33 .", "The trailer coupling 4 comprises a coupling element 6 connected solidly to the chassis or vehicle body 5 of the tractor vehicle 1 and a coupling lock 8 fixed onto a towbar 7 of the trailer vehicle 2 .", "[0035] The coupling lock 8 comprises a ball socket 9 into which a schematically represented ball head 10 of the coupling element 6 is fitted, such that the ball head 10 forms an end of the coupling element 6 at the rear thereof in relation to the driving direction 33 .", "Furthermore, the coupling lock 8 forms a front end of the towbar 7 in the driving direction 33 .", "[0036] The angle a between the longitudinal axis 11 of the tractor vehicle 1 and the longitudinal axis 12 of the trailer vehicle 2 is the so-termed bend angle or combination angle.", "In particular, the bend angle a lies in a plane perpendicular to the vertical direction 34 of the trailer vehicle 2 , the vertical direction 34 relative to the vehicle in FIG. 1 being perpendicular to the plane of the drawing.", "[0037] FIG. 2 shows a sectional view through the trailer coupling 4 along the longitudinal axis 12 and in the vehicle's vertical direction 34 , wherein at the upper end of the ball socket 9 there is attached a magnetic field sensor 13 which is fixed by means of a housing 14 .", "To the housing 14 is attached an elastic bellows 15 , which supports a sliding sleeve 16 and is connected thereto in a materially-bonded manner.", "In the sliding sleeve 16 is fitted a carrier 17 which can rotate about a rotational axis 18 , and which carries at its upper end facing toward the sensor 13 a measuring magnet 19 in the form of a permanent magnet.", "The north and south poles of the measuring magnet 19 are indicated, in order to make clear that the magnetization direction of the measuring magnet 19 is transverse to the rotational axis 18 .", "The carrier 17 , which is made from a non-magnetic material, has an upper portion 20 and a lower portion 21 mounted on the latter, an annular groove 22 being enclosed between the upper portion 20 and the lower portion 21 , in which an annular, radially inward-extending projection 23 of the sliding sleeve 16 engages.", "Thus, the carrier 17 is secured onto the sliding sleeve 16 in the direction of the rotational axis 18 .", "The rotational axis 18 extends in the vehicle's vertical direction 34 and so constitutes a vertical axis.", "[0038] To the lower end of the carrier 17 facing toward the ball head 10 is fixed a magnetically adhering body 24 comprising a permanent magnet 25 and a pot 26 in which the magnet 25 sits.", "The north and south poles of the magnet 25 are indicated in order to make clear that it is magnetized in the direction of the rotational axis 18 .", "The pot 26 consists of a magnetic material, so that the south pole of the magnet 25 appears at the rim of the pot 26 facing toward the ball head 10 .", "Needless to say, the north and south poles can be exchanged.", "[0039] The edge of the pot 26 rests against a flat area 27 of the ball head 10 and is held firmly onto it by magnetic force, since the ball head 10 too is made of a magnetic material.", "It can be seen that the north pole of the magnet 25 is slightly set back relative to the lower rim of the pot, so that direct contact between the magnet 25 and the ball head 10 is prevented.", "Moreover, an annular air gap is left between the magnet 25 and the wall of the pot 26 that surrounds it.", "[0040] In addition the coupling lock 8 comprises a catch 28 that can be actuated, which is shown in the locked condition in FIG. 2 , so that the ball head 10 is held positively in the ball socket 9 .", "For decoupling, the catch 28 can be retracted so that the coupling lock 8 can be moved clear of the ball head 10 .", "In this event the magnetically adhering body 24 is also and at the same time separated from the ball head 10 .", "[0041] In the coupled condition of the trailer coupling 4 , if the ball head 10 rotates about the rotational axis 18 relative to the coupling lock 8 the magnetically adhering body 24 rotates together with the ball head 10 .", "Since the magnetically adhering body 24 is connected by means of the carrier 17 to the measuring magnet 19 in a rotationally fixed manner, the measuring magnet 19 too rotates with the ball head 10 about the rotational axis 18 .", "the rotation can be detected by the sensor 13 , which then emits an electrical signal 29 that characterizes the rotation to an evaluation unit 30 to which the sensor 13 is connected by electric leads 31 .", "On the basis of the electric signal 29 the bend angle a is determined by the evaluation unit 30 .", "[0042] According to a first alternative the evaluation unit 30 is located in the tractor vehicle 1 , so the lead 31 extends from the coupling lock 8 to the tractor vehicle 1 .", "In a second alternative the evaluation unit 30 is in the trailer vehicle 2 , which is coupled electrically by leads 32 to the tractor vehicle 1 .", "In the latter case the information about the bend angle a can be made available to the tractor vehicle 1 via the electric leads 32 .", "[0043] In a variant embodiment the communication between the sensor 13 and the evaluation unit 30 and/or between the evaluation unit 30 and the tractor vehicle 1 can take place by wireless means, for example by radio.", "[0044] If because of uneven road conditions movements occur between the coupling lock 8 and the ball head 10 which deviate from rotation about the rotational axis 18 , for example tilting movements between the tractor vehicle 1 and the trailer vehicle 2 , then such deviant movements are accommodated by the elastic bellows 15 so that the angle measuring device or the arrangement comprising the magnetic field sensor 13 , elastic bellows 15 , sliding sleeve 16 , carrier 17 , measuring magnet 19 and magnetically adhering body 24 is not damaged.", "LIST OF INDEXES [0000] 1 Tractor vehicle 2 Trailer vehicle 3 Combination 4 Trailer coupling 5 Chassis of the tractor vehicle 6 Coupling element 7 Towbar of the trailer vehicle 8 Coupling lock 9 Ball socket 10 Ball head 11 Longitudinal axis of the tractor vehicle 12 Longitudinal axis of the trailer vehicle 13 Magnetic field sensor 14 Housing of the magnetic field sensor 15 Elastic bellows 16 Sliding sleeve 17 Carrier 18 Rotational axis 19 Measuring magnet 20 Upper portion of the carrier 21 Lower portion of the carrier 22 Annular groove in the carrier 23 Radial projection in the sliding sleeve 24 Magnetically adhering body 25 Adhering magnet 26 Pot 27 Flat area 28 Catch 29 Signal from the magnetic field sensor 30 Evaluation unit 31 Electric connection lead 32 Electric connection lead 33 Driving direction 34 Vertical direction of the vehicle" ]
CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of Ser. No. 08/821,094 filed on Mar. 20, 1997, FORMULATION FOR PRODUCING HEAT INSULATING MATERIAL AND METHOD FOR PRODUCING THE SAME, which issued as U.S. Pat. No. 5,749,960 on May 12, 1998. BACKGROUND OF THE INVENTION The present application relates broadly to heat insulating materials and, more precisely, to building products, especially those produced according to a formulation that produces a heat insulating material that can withstand a broad range of temperatures and which is formed through an exothermic reaction that is initiated at normal room temperature conditions or at lower, even cold, temperatures without requiring a heating source. There are certain known means for producing heat insulating materials for a variety of purposes or equipment, each usually requiring some external heat source. The resulting heat insulating material is therefore not formed during normal room environmental conditions, which can make the production of heat insulating material in large-dimensional constructed forms difficult and expensive due to energy and control requirements. Additionally, the currently known heat insulating materials often do not have a resistance to heat that exceeds 900° C., which consequently narrows the potential range of their application. In addition, it may become desirable to form building materials at a construction site or “in the field.” This is a virtual impossibility with materials requiring an external heat source. For another example, U.S. Pat. No. 4,110,499 discloses a heat protective material that requires the material to be subjected to temperatures in the range of 2000° F. to 2500° F. in order to obtain maximum strength. U.S. Pat. No. 5,015,606 discloses a lightweight ceramic material for building purposes that is produced by firing a foamed mixture at temperatures above 600° C. Further, U.S. Pat. No. 5,312,806 discloses mineral fibers that are for use in thermal insulation, which is made through a process that requires a coke-heated cupola furnace that operates at temperatures in the range of 1565° C. to 1605° C. When the production of heat insulating material requires the use of an external heat source, the process for such production leads to a significant increase in the heat insulating material's costs. Moreover, there are currently known heat insulating materials that use iron silicon and which may need to have heat firing during the production of the heat insulation materials. For example, a known method for making highly porous items for heat insulating equipment, consists of the use of a mixture into which a finely milled metallic silicon or iron silicon is introduced with a finely dispersed material, such as diatomite, trepel or marshalite. A liquid glass, or, as is known, a water glass, is then added in the amount necessary for turning the mixture into a thick creamy consistency. The mixture is then thoroughly mixed and heated, causing the iron silicon or silicon to react in the alkaline medium of liquid glass. For another example, U.S. Pat. No. 4,171,985 discloses the use of iron silicon with water glass in the temperature range from 5° to 90° C. in which the unaided reaction may take 24 hours to come to completion, so that heating to 90° C. is suggested “as a matter of course.” The problem with this above-described process is that the chemical reaction which produces the heat insulating material either does not start at all without heating or requires a long time to come to completion without heating. Additionally, when heat is required for the chemical reaction, the hardening of the mixture occurs during post-reaction cooling. This limits the applicability of such a mixture or process in large-dimensioned constructed forms because of associated dimensional changes. Further, the process described in the 985 Patent requires the use of the water-soluble alkali silicate, alumina cement, a metal base foaming agent and a foam stabilizing agent to produce its heat insulating material. The use of these four elements limit the applicability of the heat insulating material production during field conditions and in construction forms of large dimensions that do not have an external heat source. In order to overcome the above-mentioned defects in the previously mentioned heat insulating building materials, there is a need for specific building materials formed from a formulation for heat insulating material and a method for making the same that includes a self-starting chemical reaction that leads to a dimensionally stable, structurally strong product and which initiates at normal room or lower temperatures which eliminates the need for external heating or firing. Further, there is a need for building materials formed from a heat insulating material with a relatively low density with increased the hardness characteristics. Additionally, there is a need for such building materials formed from heat insulating material that provided lower material costs and provides building material possessing adhesive and cohesive properties. Furthermore, there is a need for building materials formed from heat resistant and heat insulating materials with dielectric properties that work in conditions of normal, low and high temperatures. SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide building materials formed from heat insulating material with a relatively low density yet with increased hardness characteristics. Further, it is an other object of the present invention to provide such building materials formed from the heat insulating material that provides lower material costs and provides adhesive and cohesive properties. It is another object of the present invention to provide such building materials formed from heat resistance and heat insulating materials with dielectric properties that work in conditions of normal, low and high temperatures. To those ends, a method for making a heat insulated reinforced block of building material includes providing a mold configured with inner dimensions equal to a desired configuration of the block of building material, providing a fluid mixture of heat insulating material formed from a predetermined composition of ingredients; providing at least one rigid reinforcement member; placing the at least one reinforcement member in the mold; introducing the fluid mixture into the mold with the at least one reinforcement member; allowing the fluid mixture to harden within the mold and removing the mixture from the mold, resulting in a block of reinforced heat insulated building material. It is preferred that the step providing a fluid mixture of heat insulating material includes providing the fluid mixture of heat insulating material formed from a composition of the following ingredients and the following amounts: Water Glass 32-52% by weight Sodium Hydroxide  3-4% by weight Filler 25-36% by weight Iron Silicon 20-22% by weight Preferably, the step placing the at least one reinforcement member in the mold includes placing the reinforcement member in the mold in a disposition where in at least a portion of the reinforcement member forms at least a portion of an outer surface of the block of building material and extends longitudinally along the block. It is further preferred that the step of providing at least one rigid reinforcement member includes providing a plurality of reinforcement members and the step of placing at least one reinforcement member in the mold includes placing a predetermined number of reinforcement members in the mold with at least a portion of the predetermined number of reinforcement members forming at least a portion of an outer surface of the block. It is preferred that the step of providing a fluid mixture of heat insulating material includes providing heat insulating material formed with the ingredients at temperatures in the range between room temperature and approximately minus 10° C. Preferably, the step of providing heat insulating material includes providing heat insulating material as formed through an exothermic reaction that produces a formulation that hardens without the use of an external energy source. It is further preferred that the step of providing a fluid mixture of heat insulating material includes providing a filler formed from firing clay. Preferably the step of providing a fluid mixture of heat insulating material includes providing water glass having a SiO 2 /Na 2 ratio (modulus) that is within the approximate range 2.4 to 3.0 with a density of approximately 1.41 to 1.47 gm/cm 3 . The step of providing a fluid mixture of heat insulating material also may include providing water glass formed from sodium silicate. In another preferred embodiment of the present invention the method includes the steps of providing a mold configured with inner dimensions equal to a desired configuration of the block of building material; providing a plurality of hardened structures of heat insulating material formed from a predetermined composition of ingredients; providing at least one rigid reinforcement member; providing a fluid mixture of heat insulating material formed from the predetermined composition of ingredients; placing the hardened structures and the at least one reinforcement member in the mold with the at least one reinforcement member being disposed between the hardened structures; introducing the fluid mixture into the mold to surround the hardened structures and the at least one reinforcement member allowing the fluid material to harden within the mold and removing the mixture from the mold, resulting in a block of reinforced heat insulating building material. Preferably, the steps of providing a plurality of hardened structures of heat insulating material and providing a fluid mixture of heat insulating material including providing both the hardened structures and the fluid mixture formed from a composition of ingredients as described above. It is further preferred that a plurality of reinforcement members are provided and the step of placing the hardened structures and the at least one reinforcement member in the mold includes placing the hardened structures and the reinforcement members in alternating layers within the mold. It is further preferred that the step of providing at least one reinforcement member includes providing the at least one reinforcement member formed as a generally elongate steel channel. Further, the step of placing at least one reinforcement member in the mold includes placing the reinforcement member in the mold in a disposition where in at least a portion of the reinforcement member forms at least a portion of an outer surface of the block of building material. It is preferred that the step of placing at least one reinforcement member in the mold includes placing the reinforcement member in the mold at a disposition extending longitudinally along the block. It is also preferred that the step of placing the at least one reinforcement member in the mold includes placing the reinforcement member in the mold at a disposition extending width-wise across the block. According to another preferred embodiment of the present invention, the method includes the steps of providing a mold configured with inner dimensions equal to a desired configuration of the block of building materials; providing a fluid mixture of heat insulating material formed from a predetermined composition of ingredients, providing a plurality of rigid reinforcement members; placing the predetermined number of reinforcement members in the mold, with the predetermined number reinforcement members forming at least a portion of first surface of the blocks; introducing the fluid mixture into the mold with a predetermined number of reinforcement members; allowing the fluid material to harden within the mold; and removing the mixture from the mold, resulting in a block of reinforced heat insulating building material. Preferably the step of providing a fluid mixture includes providing a fluid mixture of heat insulating material formed from a composition of ingredients as described above. Further, the present invention preferably includes the step of placing a second predetermined number of reinforced members in the mold, on the fluid mixture prior to hardening thereof at a disposition where in at least a portion of the second predetermined number of reinforcement members forms at least a portion of the second outer surface of the block. The present invention is also directed to a heat insulated, reinforced block of building material formed from the above-discussed methods. The block of building material includes a molded polygonal unit having a predetermined volume and being formed from a hardened fluid mixture of heat insulating material, the fluid mixture of heat insulating material being formed from a predetermined composition of ingredients, the unit having at least one reinforcement member disposed at least partially internally thereof. Preferably, the fluid mixture of heat insulating material is formed from a composition of ingredients as described above. The building material according to the present invention preferably further includes a plurality of hardened structures of heat insulating material formed from the predetermined composition of ingredients and disposed internally within the block with at least one reinforcement member disposed intermediate at least two of the hardened structures. It is preferred that the hardened structures are formed from a composition of ingredients as described above. It is further preferred that the at least one reinforcement member be formed from steel. Preferably, the at least one reinforcement member is disposed internally within the unit and extends width-wise thereof. It is alternately preferred that the unit include a plurality of reinforcement members extending longitudinally along the block and at least a portion of the reinforcement members forms at least a portion of an outer wall of the block. It is preferred that the heat insulating material be formed through an exothermic reaction that produces a formulation that hardens without the use of an external energy source. Further, the filler is preferably formed of firing clay. It is further preferred that the water glass have an SiO 2 /Na 2 O ratio (modulus) that is within the approximately range 2.4 to 3.0 with a density of approximately 1.41 to 1.47 gm/cm 3 . Preferably, the water glass is sodium silicon. By the above, the present invention provides a method for producing a block of reinforced building material formed from low density heat insulating material and building products produced according to the method. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a heat insulated reinforced block of building material according to one preferred embodiment of the present invention, broken open to reveal the internal structure thereof; FIG. 2 is a perspective view of a mold receiving heat insulated material according to the method of the present invention; FIG. 3 is a perspective view of a heat insulated reinforced block of building material according to a second preferred embodiment thereof; FIG. 4 is a cross sectional view of a mold receiving heat insulated building material according to a second preferred embodiment of the present invention; and FIG. 5 is a cross sectional view of a mold filled with heat insulating material including reinforcement members according to the method of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings and, more particularly to FIG. 1, the first preferred embodiment of the present invention is illustrated as a heat insulated reinforced block of building material broken open to reveal the inner structure thereof and is illustrated generally at 10 . The present invention includes a method for forming the block as well as at least one more embodiment thereof. FIG. 1 reveals the block 10 to include a solid body 12 formed from heat insulating material which will be described in greater detail hereinafter. Within the body 12 , a stack of hardened structures 14 are provided in alternating layers with elongate steel channels 16 which provide reinforcement of the block 10 . The hardened structures 14 are formed generally as cubes and are made from the same heat insulating material as is the body 12 of the block 10 . It should be noted that while cubes are illustrated, the hardened structures 14 maybe formed as cylinders or any other geometric structure that will provide positioning for the steel reinforcement member 16 during the molding process. Once the block is molded, the hardened structures 14 become substantially integral with the body 12 of the block 10 . The reinforcement members 16 will provide the relatively light block with the ability to withstand crushing forces and should therefor be disposed in a generally parallel relationship with the outer surfaces of the block so that the block may be oriented with the reinforcement members running along the direction of compression when the blocks are in use. The second preferred embodiment of the present invention is illustrated in FIG. 3 . There, the block 30 is formed as a generally elongate, relatively flat wall panel 32 formed from the heat insulating material 18 and includes four elongate steel channels 34 disposed at four corners thereof with an outer surface of the steel channels 34 forming a portion of the outer surface of the wall panel 30 . Since the hardened heat insulating material 18 is relatively brittle and is formed with numerous pores which provide a rough surface, the smooth outer surface of the steel channels 34 provides the wall panel 30 with a mounting surface which will support screws, other fasteners or other attachments in general. Both of the preferred embodiments of the present invention are formed according to the method of the present invention and require a formulation of heat insulating material for molding as seen in FIGS. 2 and 4. According to the formulation for producing a heat insulating material and the method for making such material, the heat insulating material is made by mixing an iron/silicon alloy with water glass (sodium silicate, which is the same as “liquid glass”), thereby providing the water necessary for the reaction. The reaction follows a path similar to that of the well-known alkaline corrosion of iron in water to produce hydrated ferric oxide and hydrogen. The evolution of water resulting from the solvent evaporation aids in the formation of material with structural integrity. Additionally, firing clay can act as a binder, which, together with dehydrated sodium silicate, forms a typical two or three dimensional matrix of SiO 3 tetrahedra, which likely contributes to the physical strength of the building products made from the heat insulating material. The key is in the initial reaction of iron/silicon alloy with water in an alkaline medium. The reaction initiation is spontaneous and immediate when the ingredients are mixed and the reaction is completed in a relatively short time. In addition, the heat insulating material utilized in the present invention is stable when exposed to high temperatures and is based on inorganic materials. Further, the heat insulating material is made from a formulation that uses sodium silicate and produces a foam without the use of either an anionic surfactant, chromium or aluminum. Finally, the heat insulating material does not require the use of high temperature firing or pressure molding. The formulation involves an exothermic reaction which depends on sodium silicate or liquid glass, sodium hydroxide, iron silicon and a filler, such as the aforesaid firing clay. More specifically, iron silicon reacts in an exothermic reaction in an alkaline medium resulting in a rapid release of energy in the form of heat. As a result of the exothermic reaction, the mixed formulation self-heats to temperatures near 100° C. The formulation becomes porous as a result of the formation of water vapor and hydrogen, and hardens as a result of water loss. Pore formation results in an increase of many times the volume and lowers the density of the resulting heat insulating material and, consequently, the weight of building materials formed from the material. The loss of water, in addition to contributing to pore formation, also leads to an increase in the dielectric qualities of the material. Additionally, the reaction of the iron component in iron silicon contributes to the heat resistance of the resulting heat insulating material. The presence of sodium hydroxide is necessary for the reaction of the formulation that results in the heat insulating material and makes it possible for the reaction to occur at normal room temperature or at temperatures down to −10° C. Sodium hydroxide contributes to the speed with which the reaction occurs, thus insuring an adequate temperature rise and the evolution of water which results in pore formation. The increased temperature also facilitates water loss, thus contributing to the hardening of the heat insulating material. The firing clay in the formulation provides for the necessary viscosity of the initial mixture, and contributes to the heat resistance of the heat insulating material. Other materials, such as kaolin or other finely dispersed powders, which perform analogous functions in providing viscosity and heat resistance, may be used instead of firing clay. The ratio of SiO 2 to Na 2 O (modulus) for the sodium silicate or liquid glass is in the approximate range of 2.4 to 3.0, given the density of 1.41 to 1.47 g/cm 3 . The values of the dispersion of the iron silicon are determined by the specific area of 0.004 to 0.005 cm 2 /g, which allows for varying the viscosity of the formulation and its reactivity. In general, the formulation for producing the heat insulating material having the qualities described above is prepared using the following basic steps: (a) Granules of sodium hydroxide are added to the liquid glass and the solution is agitated to ensure complete dissolution. The iron silicon and the firing clay are added. (b) The mixture is again agitated until a homogeneous plastic consistency is achieved and is then poured into a form or mold, as will be described in greater detail hereinafter. (c) The resulting heat insulating material expands and hardens under normal conditions within 1 to 1.5 hours, substantially filling up the volume of the form or mold. Further, in the process of hardening, hydrogen is produced, and during the final stage of hardening, water vapor is evolved as the product temperature rises to near 100° C. as a result of the reaction exothermicity. In Table 1 shown below, examples of different fillers/binders are identified for use in the proposed formulation of the present invention in which part of the firing clay is replaced with the proposed filler. In this manner, the proposed formulation may be used with various fillers as a means for producing materials having the desired physical-mechanical properties. TABLE 1 Compound - Binder Component Mass % Liquid Glass −52 Sodium Hydroxide 4 Firing Clay 16 Iron Silicon 28 Filler/Binder = 3/1 Parameter Sand/Binder Ceramic/Binder Density - Kg/m 3 1750 760 Limit of Hardness under Compression - 37.4 5.32 MGa Heat Transfer Coefficient - Wt/m. ° C. 0.85 0.54 Time of Hardening - Min. 120 120 Working Temperature Range - ° C. 1400 1100 The possible reactions in the formulation of the present invention for the heat insulating material are: 1. Fe+2H 2 O→Fe(OH) 2 +H 2 (alkaline medium) 2. 2Fe(OH) 2 +O 2 (air)+xH 2 O→Fe 2 O 3 ·(x+2)H 2 O Reactions 1 and 2 represent a normal oxidation process which will be more rapid in the presence of finely divided iron. The reaction is exothermic. Mixing FeSi with a few drops of 0.5M NaOH produces rapid warming, indicating that reaction 1 is indeed proceeding. Since the entire process is carried out “in the open”, air is surely present to supply oxygen for reaction 2. The expected water of hydration will be lost as the temperature of the mixture increases. 3. 2FeSi+3O 2 →2FeSiO 3 Reaction 3 is one of the possible reactions in slag formation and may indeed occur here. Normally one would expect this silicate formation to occur at higher temperatures such as might be found in steel making ovens. The extent to which this reaction occurs will reduce the observed weight loss in the thermo-gravimetric analysis by reducing the extent of involvement of reaction 1 and by adding weight through oxygen incorporation. It is unlikely that reaction 3 occurs to any significant extent given the weight loss result reported below. 4. Si+H 2 O+2NaOH→Na 2 SiO 3 +2H 2 Reaction 4 is also exothermic and releases hydrogen gas. Isothermal (28° C.) thermo-gravimetric analysis of the entire system as supplied, resulted in a weight loss of 13.9%. The sodium silicate used is a 42° Beaumé product containing 29.6% SiO 2 , and 9.20% Na 2 O and therefore 61.2% water. On total material composition, this amounts to 23.2% water. Taking the composition of FeSi into account (approximately 25% Fe and 75% Si), the weight loss due to hydrogen evolution (reaction 1) is expected to be 0.27%. The weight gain due to oxidation (reactions 1 plus 2) amounts to 3.7%. Thus, the theoretical weight loss is expected to be 19.8%. In a second thermo-gravimetric analysis performed on the reaction product and carried out in stepped temperature mode, an additional weight loss of 4.9% on total reaction charge was measured giving a total weight loss of 18.8%, which compares reasonably with the theoretical. In summary, the formulation for producing a heat insulating material has a self-starting exothermic chemical reaction which hardens the heat insulating material. The chemical reaction can occur in the temperature range between normal room temperatures and 10° C., and does not require an external heat source. The percentages of the components of the formulation are: Water Glass 32-52% by weight Sodium Hydroxide  3-4% by weight Firing Clay 25-36% by weight Iron Silicon 20-22% by weight Returning now to FIG. 2, the reinforced block of building material according to one preferred embodiment of the present invention is formed according to the method of the present invention using the formulation previously described. First, the internal structure is formed which may be seen in FIGS. 1 and 2. As also previously described, a preformed mold (not shown) is used to form a plurality of cubes of the heat insulating material. The cubes are allowed to harden and are then arranged within the mold. A first cube is placed in the mold and a steel channel is placed on top of the cube. The cubes in the channel are placed within the mold in an alternating manner to arrive at the stack illustrated in FIGS. 1 and 2. The mold 20 is formed from wood or other material to define a mold interior 22 for receiving the stack of hardened structures 14 and steel channel 16 . The mold is preferably rectangular but is not limited to a rectangular configuration. Nevertheless, the regular shape offered by a rectangular mold lends itself well to producing blocks of building material. The heat insulating material 28 if formed according to the formulation described above and is poured from a vessel 26 or otherwise introduced into the interior 22 of the mold 20 to completely fill the mold. As seen in FIG. 5, a top portion 24 is placed on the upper surface of the insulating material 28 to define a six-sided structure once the mold is removed. It should be noted that while the insulating material 28 is shown being poured from a bucket 26 , this technique is generally performed at a building site and the mass production of blocks according to the present invention will likely progress with the heat insulating material 28 flowing from a piping system or other delivery system. Therefore, it should not be presumed under any conditions that the heat insulating material 28 must be poured into the mold 20 . In any event, the heat insulating material 28 is allowed to harden and the mold is broken away from the structure formed therein which provides the block 10 as illustrated in FIG. 1 . According to another preferred embodiment of the present invention, and with reference to FIG. 4, two steel channels 34 are placed in the bottom of the mold and the heat insulating material 28 is introduced into the interior 22 of the mold as previously described. With reference to FIG. 5, once the mold 20 has been filled with heat insulating material 28 , two more steel channels 34 are disposed at upper surface of the heat insulating material 28 . As seen in FIG. 5, a top 24 is placed on the steel channels 34 and the flowable heat insulating material 28 is allowed to harden into a hardened heat insulating material 18 as described in the discussion of the formulation. It will be apparent that those skilled in the art that the amount of heat insulating material introduced into the mold 28 must be regulated as the material expands when it cools. Trial and error or sophisticated density/volume calculations can provide the necessary amount of flowable material that will fill up the mold. Further, it is contemplated if the blocks are produced in great numbers, a computer may be employed to feed heat insulating material into the mold 20 in metered amounts sufficient to provide the necessary structure while not overfilling the mold. Once the heat insulating material 18 has hardened, the mold may be removed from around the block 10 and the block 10 then used for building material. Blocks according to the present invention have many uses and can form mold structures to provide light, heat insulated and heat resistant walls for a building. Further, interior wall panels may be placed over the outer steel channels of the blocks illustrated in FIG. 3 . Therefore, the present invention provides a lightweight, strong material for construction purposes. It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.
A method for forming building products from heat insulated material and building products formed in accordance therewith includes providing a mold configured with inner dimensions equal to the desired configuration of the building material block; providing a fluid mixture of heat insulating material formed from a predetermined composition of ingredients; providing at least one rigid reinforcement member and placing the reinforcement member in the mold; introducing the fluid mixture into the mold with the at least one reinforcement member and allowing the fluid mixture to harden within the mold and removing the mixture from the mold resulting in a block of reinforced heat insulating building material. The present invention is also directed to a block of reinforced heat insulated building material according to the method.
Analyze the document's illustrations and descriptions to summarize the main idea's core structure and function.
[ "CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of Ser.", "No. 08/821,094 filed on Mar. 20, 1997, FORMULATION FOR PRODUCING HEAT INSULATING MATERIAL AND METHOD FOR PRODUCING THE SAME, which issued as U.S. Pat. No. 5,749,960 on May 12, 1998.", "BACKGROUND OF THE INVENTION The present application relates broadly to heat insulating materials and, more precisely, to building products, especially those produced according to a formulation that produces a heat insulating material that can withstand a broad range of temperatures and which is formed through an exothermic reaction that is initiated at normal room temperature conditions or at lower, even cold, temperatures without requiring a heating source.", "There are certain known means for producing heat insulating materials for a variety of purposes or equipment, each usually requiring some external heat source.", "The resulting heat insulating material is therefore not formed during normal room environmental conditions, which can make the production of heat insulating material in large-dimensional constructed forms difficult and expensive due to energy and control requirements.", "Additionally, the currently known heat insulating materials often do not have a resistance to heat that exceeds 900° C., which consequently narrows the potential range of their application.", "In addition, it may become desirable to form building materials at a construction site or “in the field.”", "This is a virtual impossibility with materials requiring an external heat source.", "For another example, U.S. Pat. No. 4,110,499 discloses a heat protective material that requires the material to be subjected to temperatures in the range of 2000° F. to 2500° F. in order to obtain maximum strength.", "U.S. Pat. No. 5,015,606 discloses a lightweight ceramic material for building purposes that is produced by firing a foamed mixture at temperatures above 600° C. Further, U.S. Pat. No. 5,312,806 discloses mineral fibers that are for use in thermal insulation, which is made through a process that requires a coke-heated cupola furnace that operates at temperatures in the range of 1565° C. to 1605° C. When the production of heat insulating material requires the use of an external heat source, the process for such production leads to a significant increase in the heat insulating material's costs.", "Moreover, there are currently known heat insulating materials that use iron silicon and which may need to have heat firing during the production of the heat insulation materials.", "For example, a known method for making highly porous items for heat insulating equipment, consists of the use of a mixture into which a finely milled metallic silicon or iron silicon is introduced with a finely dispersed material, such as diatomite, trepel or marshalite.", "A liquid glass, or, as is known, a water glass, is then added in the amount necessary for turning the mixture into a thick creamy consistency.", "The mixture is then thoroughly mixed and heated, causing the iron silicon or silicon to react in the alkaline medium of liquid glass.", "For another example, U.S. Pat. No. 4,171,985 discloses the use of iron silicon with water glass in the temperature range from 5° to 90° C. in which the unaided reaction may take 24 hours to come to completion, so that heating to 90° C. is suggested “as a matter of course.”", "The problem with this above-described process is that the chemical reaction which produces the heat insulating material either does not start at all without heating or requires a long time to come to completion without heating.", "Additionally, when heat is required for the chemical reaction, the hardening of the mixture occurs during post-reaction cooling.", "This limits the applicability of such a mixture or process in large-dimensioned constructed forms because of associated dimensional changes.", "Further, the process described in the 985 Patent requires the use of the water-soluble alkali silicate, alumina cement, a metal base foaming agent and a foam stabilizing agent to produce its heat insulating material.", "The use of these four elements limit the applicability of the heat insulating material production during field conditions and in construction forms of large dimensions that do not have an external heat source.", "In order to overcome the above-mentioned defects in the previously mentioned heat insulating building materials, there is a need for specific building materials formed from a formulation for heat insulating material and a method for making the same that includes a self-starting chemical reaction that leads to a dimensionally stable, structurally strong product and which initiates at normal room or lower temperatures which eliminates the need for external heating or firing.", "Further, there is a need for building materials formed from a heat insulating material with a relatively low density with increased the hardness characteristics.", "Additionally, there is a need for such building materials formed from heat insulating material that provided lower material costs and provides building material possessing adhesive and cohesive properties.", "Furthermore, there is a need for building materials formed from heat resistant and heat insulating materials with dielectric properties that work in conditions of normal, low and high temperatures.", "SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide building materials formed from heat insulating material with a relatively low density yet with increased hardness characteristics.", "Further, it is an other object of the present invention to provide such building materials formed from the heat insulating material that provides lower material costs and provides adhesive and cohesive properties.", "It is another object of the present invention to provide such building materials formed from heat resistance and heat insulating materials with dielectric properties that work in conditions of normal, low and high temperatures.", "To those ends, a method for making a heat insulated reinforced block of building material includes providing a mold configured with inner dimensions equal to a desired configuration of the block of building material, providing a fluid mixture of heat insulating material formed from a predetermined composition of ingredients;", "providing at least one rigid reinforcement member;", "placing the at least one reinforcement member in the mold;", "introducing the fluid mixture into the mold with the at least one reinforcement member;", "allowing the fluid mixture to harden within the mold and removing the mixture from the mold, resulting in a block of reinforced heat insulated building material.", "It is preferred that the step providing a fluid mixture of heat insulating material includes providing the fluid mixture of heat insulating material formed from a composition of the following ingredients and the following amounts: Water Glass 32-52% by weight Sodium Hydroxide 3-4% by weight Filler 25-36% by weight Iron Silicon 20-22% by weight Preferably, the step placing the at least one reinforcement member in the mold includes placing the reinforcement member in the mold in a disposition where in at least a portion of the reinforcement member forms at least a portion of an outer surface of the block of building material and extends longitudinally along the block.", "It is further preferred that the step of providing at least one rigid reinforcement member includes providing a plurality of reinforcement members and the step of placing at least one reinforcement member in the mold includes placing a predetermined number of reinforcement members in the mold with at least a portion of the predetermined number of reinforcement members forming at least a portion of an outer surface of the block.", "It is preferred that the step of providing a fluid mixture of heat insulating material includes providing heat insulating material formed with the ingredients at temperatures in the range between room temperature and approximately minus 10° C. Preferably, the step of providing heat insulating material includes providing heat insulating material as formed through an exothermic reaction that produces a formulation that hardens without the use of an external energy source.", "It is further preferred that the step of providing a fluid mixture of heat insulating material includes providing a filler formed from firing clay.", "Preferably the step of providing a fluid mixture of heat insulating material includes providing water glass having a SiO 2 /Na 2 ratio (modulus) that is within the approximate range 2.4 to 3.0 with a density of approximately 1.41 to 1.47 gm/cm 3 .", "The step of providing a fluid mixture of heat insulating material also may include providing water glass formed from sodium silicate.", "In another preferred embodiment of the present invention the method includes the steps of providing a mold configured with inner dimensions equal to a desired configuration of the block of building material;", "providing a plurality of hardened structures of heat insulating material formed from a predetermined composition of ingredients;", "providing at least one rigid reinforcement member;", "providing a fluid mixture of heat insulating material formed from the predetermined composition of ingredients;", "placing the hardened structures and the at least one reinforcement member in the mold with the at least one reinforcement member being disposed between the hardened structures;", "introducing the fluid mixture into the mold to surround the hardened structures and the at least one reinforcement member allowing the fluid material to harden within the mold and removing the mixture from the mold, resulting in a block of reinforced heat insulating building material.", "Preferably, the steps of providing a plurality of hardened structures of heat insulating material and providing a fluid mixture of heat insulating material including providing both the hardened structures and the fluid mixture formed from a composition of ingredients as described above.", "It is further preferred that a plurality of reinforcement members are provided and the step of placing the hardened structures and the at least one reinforcement member in the mold includes placing the hardened structures and the reinforcement members in alternating layers within the mold.", "It is further preferred that the step of providing at least one reinforcement member includes providing the at least one reinforcement member formed as a generally elongate steel channel.", "Further, the step of placing at least one reinforcement member in the mold includes placing the reinforcement member in the mold in a disposition where in at least a portion of the reinforcement member forms at least a portion of an outer surface of the block of building material.", "It is preferred that the step of placing at least one reinforcement member in the mold includes placing the reinforcement member in the mold at a disposition extending longitudinally along the block.", "It is also preferred that the step of placing the at least one reinforcement member in the mold includes placing the reinforcement member in the mold at a disposition extending width-wise across the block.", "According to another preferred embodiment of the present invention, the method includes the steps of providing a mold configured with inner dimensions equal to a desired configuration of the block of building materials;", "providing a fluid mixture of heat insulating material formed from a predetermined composition of ingredients, providing a plurality of rigid reinforcement members;", "placing the predetermined number of reinforcement members in the mold, with the predetermined number reinforcement members forming at least a portion of first surface of the blocks;", "introducing the fluid mixture into the mold with a predetermined number of reinforcement members;", "allowing the fluid material to harden within the mold;", "and removing the mixture from the mold, resulting in a block of reinforced heat insulating building material.", "Preferably the step of providing a fluid mixture includes providing a fluid mixture of heat insulating material formed from a composition of ingredients as described above.", "Further, the present invention preferably includes the step of placing a second predetermined number of reinforced members in the mold, on the fluid mixture prior to hardening thereof at a disposition where in at least a portion of the second predetermined number of reinforcement members forms at least a portion of the second outer surface of the block.", "The present invention is also directed to a heat insulated, reinforced block of building material formed from the above-discussed methods.", "The block of building material includes a molded polygonal unit having a predetermined volume and being formed from a hardened fluid mixture of heat insulating material, the fluid mixture of heat insulating material being formed from a predetermined composition of ingredients, the unit having at least one reinforcement member disposed at least partially internally thereof.", "Preferably, the fluid mixture of heat insulating material is formed from a composition of ingredients as described above.", "The building material according to the present invention preferably further includes a plurality of hardened structures of heat insulating material formed from the predetermined composition of ingredients and disposed internally within the block with at least one reinforcement member disposed intermediate at least two of the hardened structures.", "It is preferred that the hardened structures are formed from a composition of ingredients as described above.", "It is further preferred that the at least one reinforcement member be formed from steel.", "Preferably, the at least one reinforcement member is disposed internally within the unit and extends width-wise thereof.", "It is alternately preferred that the unit include a plurality of reinforcement members extending longitudinally along the block and at least a portion of the reinforcement members forms at least a portion of an outer wall of the block.", "It is preferred that the heat insulating material be formed through an exothermic reaction that produces a formulation that hardens without the use of an external energy source.", "Further, the filler is preferably formed of firing clay.", "It is further preferred that the water glass have an SiO 2 /Na 2 O ratio (modulus) that is within the approximately range 2.4 to 3.0 with a density of approximately 1.41 to 1.47 gm/cm 3 .", "Preferably, the water glass is sodium silicon.", "By the above, the present invention provides a method for producing a block of reinforced building material formed from low density heat insulating material and building products produced according to the method.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a heat insulated reinforced block of building material according to one preferred embodiment of the present invention, broken open to reveal the internal structure thereof;", "FIG. 2 is a perspective view of a mold receiving heat insulated material according to the method of the present invention;", "FIG. 3 is a perspective view of a heat insulated reinforced block of building material according to a second preferred embodiment thereof;", "FIG. 4 is a cross sectional view of a mold receiving heat insulated building material according to a second preferred embodiment of the present invention;", "and FIG. 5 is a cross sectional view of a mold filled with heat insulating material including reinforcement members according to the method of the present invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings and, more particularly to FIG. 1, the first preferred embodiment of the present invention is illustrated as a heat insulated reinforced block of building material broken open to reveal the inner structure thereof and is illustrated generally at 10 .", "The present invention includes a method for forming the block as well as at least one more embodiment thereof.", "FIG. 1 reveals the block 10 to include a solid body 12 formed from heat insulating material which will be described in greater detail hereinafter.", "Within the body 12 , a stack of hardened structures 14 are provided in alternating layers with elongate steel channels 16 which provide reinforcement of the block 10 .", "The hardened structures 14 are formed generally as cubes and are made from the same heat insulating material as is the body 12 of the block 10 .", "It should be noted that while cubes are illustrated, the hardened structures 14 maybe formed as cylinders or any other geometric structure that will provide positioning for the steel reinforcement member 16 during the molding process.", "Once the block is molded, the hardened structures 14 become substantially integral with the body 12 of the block 10 .", "The reinforcement members 16 will provide the relatively light block with the ability to withstand crushing forces and should therefor be disposed in a generally parallel relationship with the outer surfaces of the block so that the block may be oriented with the reinforcement members running along the direction of compression when the blocks are in use.", "The second preferred embodiment of the present invention is illustrated in FIG. 3 .", "There, the block 30 is formed as a generally elongate, relatively flat wall panel 32 formed from the heat insulating material 18 and includes four elongate steel channels 34 disposed at four corners thereof with an outer surface of the steel channels 34 forming a portion of the outer surface of the wall panel 30 .", "Since the hardened heat insulating material 18 is relatively brittle and is formed with numerous pores which provide a rough surface, the smooth outer surface of the steel channels 34 provides the wall panel 30 with a mounting surface which will support screws, other fasteners or other attachments in general.", "Both of the preferred embodiments of the present invention are formed according to the method of the present invention and require a formulation of heat insulating material for molding as seen in FIGS. 2 and 4.", "According to the formulation for producing a heat insulating material and the method for making such material, the heat insulating material is made by mixing an iron/silicon alloy with water glass (sodium silicate, which is the same as “liquid glass”), thereby providing the water necessary for the reaction.", "The reaction follows a path similar to that of the well-known alkaline corrosion of iron in water to produce hydrated ferric oxide and hydrogen.", "The evolution of water resulting from the solvent evaporation aids in the formation of material with structural integrity.", "Additionally, firing clay can act as a binder, which, together with dehydrated sodium silicate, forms a typical two or three dimensional matrix of SiO 3 tetrahedra, which likely contributes to the physical strength of the building products made from the heat insulating material.", "The key is in the initial reaction of iron/silicon alloy with water in an alkaline medium.", "The reaction initiation is spontaneous and immediate when the ingredients are mixed and the reaction is completed in a relatively short time.", "In addition, the heat insulating material utilized in the present invention is stable when exposed to high temperatures and is based on inorganic materials.", "Further, the heat insulating material is made from a formulation that uses sodium silicate and produces a foam without the use of either an anionic surfactant, chromium or aluminum.", "Finally, the heat insulating material does not require the use of high temperature firing or pressure molding.", "The formulation involves an exothermic reaction which depends on sodium silicate or liquid glass, sodium hydroxide, iron silicon and a filler, such as the aforesaid firing clay.", "More specifically, iron silicon reacts in an exothermic reaction in an alkaline medium resulting in a rapid release of energy in the form of heat.", "As a result of the exothermic reaction, the mixed formulation self-heats to temperatures near 100° C. The formulation becomes porous as a result of the formation of water vapor and hydrogen, and hardens as a result of water loss.", "Pore formation results in an increase of many times the volume and lowers the density of the resulting heat insulating material and, consequently, the weight of building materials formed from the material.", "The loss of water, in addition to contributing to pore formation, also leads to an increase in the dielectric qualities of the material.", "Additionally, the reaction of the iron component in iron silicon contributes to the heat resistance of the resulting heat insulating material.", "The presence of sodium hydroxide is necessary for the reaction of the formulation that results in the heat insulating material and makes it possible for the reaction to occur at normal room temperature or at temperatures down to −10° C. Sodium hydroxide contributes to the speed with which the reaction occurs, thus insuring an adequate temperature rise and the evolution of water which results in pore formation.", "The increased temperature also facilitates water loss, thus contributing to the hardening of the heat insulating material.", "The firing clay in the formulation provides for the necessary viscosity of the initial mixture, and contributes to the heat resistance of the heat insulating material.", "Other materials, such as kaolin or other finely dispersed powders, which perform analogous functions in providing viscosity and heat resistance, may be used instead of firing clay.", "The ratio of SiO 2 to Na 2 O (modulus) for the sodium silicate or liquid glass is in the approximate range of 2.4 to 3.0, given the density of 1.41 to 1.47 g/cm 3 .", "The values of the dispersion of the iron silicon are determined by the specific area of 0.004 to 0.005 cm 2 /g, which allows for varying the viscosity of the formulation and its reactivity.", "In general, the formulation for producing the heat insulating material having the qualities described above is prepared using the following basic steps: (a) Granules of sodium hydroxide are added to the liquid glass and the solution is agitated to ensure complete dissolution.", "The iron silicon and the firing clay are added.", "(b) The mixture is again agitated until a homogeneous plastic consistency is achieved and is then poured into a form or mold, as will be described in greater detail hereinafter.", "(c) The resulting heat insulating material expands and hardens under normal conditions within 1 to 1.5 hours, substantially filling up the volume of the form or mold.", "Further, in the process of hardening, hydrogen is produced, and during the final stage of hardening, water vapor is evolved as the product temperature rises to near 100° C. as a result of the reaction exothermicity.", "In Table 1 shown below, examples of different fillers/binders are identified for use in the proposed formulation of the present invention in which part of the firing clay is replaced with the proposed filler.", "In this manner, the proposed formulation may be used with various fillers as a means for producing materials having the desired physical-mechanical properties.", "TABLE 1 Compound - Binder Component Mass % Liquid Glass −52 Sodium Hydroxide 4 Firing Clay 16 Iron Silicon 28 Filler/Binder = 3/1 Parameter Sand/Binder Ceramic/Binder Density - Kg/m 3 1750 760 Limit of Hardness under Compression - 37.4 5.32 MGa Heat Transfer Coefficient - Wt/m.", "° C. 0.85 0.54 Time of Hardening - Min.", "120 120 Working Temperature Range - ° C. 1400 1100 The possible reactions in the formulation of the present invention for the heat insulating material are: 1.", "Fe+2H 2 O→Fe(OH) 2 +H 2 (alkaline medium) 2.", "2Fe(OH) 2 +O 2 (air)+xH 2 O→Fe 2 O 3 ·(x+2)H 2 O Reactions 1 and 2 represent a normal oxidation process which will be more rapid in the presence of finely divided iron.", "The reaction is exothermic.", "Mixing FeSi with a few drops of 0.5M NaOH produces rapid warming, indicating that reaction 1 is indeed proceeding.", "Since the entire process is carried out “in the open”, air is surely present to supply oxygen for reaction 2.", "The expected water of hydration will be lost as the temperature of the mixture increases.", "2FeSi+3O 2 →2FeSiO 3 Reaction 3 is one of the possible reactions in slag formation and may indeed occur here.", "Normally one would expect this silicate formation to occur at higher temperatures such as might be found in steel making ovens.", "The extent to which this reaction occurs will reduce the observed weight loss in the thermo-gravimetric analysis by reducing the extent of involvement of reaction 1 and by adding weight through oxygen incorporation.", "It is unlikely that reaction 3 occurs to any significant extent given the weight loss result reported below.", "Si+H 2 O+2NaOH→Na 2 SiO 3 +2H 2 Reaction 4 is also exothermic and releases hydrogen gas.", "Isothermal (28° C.) thermo-gravimetric analysis of the entire system as supplied, resulted in a weight loss of 13.9%.", "The sodium silicate used is a 42° Beaumé product containing 29.6% SiO 2 , and 9.20% Na 2 O and therefore 61.2% water.", "On total material composition, this amounts to 23.2% water.", "Taking the composition of FeSi into account (approximately 25% Fe and 75% Si), the weight loss due to hydrogen evolution (reaction 1) is expected to be 0.27%.", "The weight gain due to oxidation (reactions 1 plus 2) amounts to 3.7%.", "Thus, the theoretical weight loss is expected to be 19.8%.", "In a second thermo-gravimetric analysis performed on the reaction product and carried out in stepped temperature mode, an additional weight loss of 4.9% on total reaction charge was measured giving a total weight loss of 18.8%, which compares reasonably with the theoretical.", "In summary, the formulation for producing a heat insulating material has a self-starting exothermic chemical reaction which hardens the heat insulating material.", "The chemical reaction can occur in the temperature range between normal room temperatures and 10° C., and does not require an external heat source.", "The percentages of the components of the formulation are: Water Glass 32-52% by weight Sodium Hydroxide 3-4% by weight Firing Clay 25-36% by weight Iron Silicon 20-22% by weight Returning now to FIG. 2, the reinforced block of building material according to one preferred embodiment of the present invention is formed according to the method of the present invention using the formulation previously described.", "First, the internal structure is formed which may be seen in FIGS. 1 and 2.", "As also previously described, a preformed mold (not shown) is used to form a plurality of cubes of the heat insulating material.", "The cubes are allowed to harden and are then arranged within the mold.", "A first cube is placed in the mold and a steel channel is placed on top of the cube.", "The cubes in the channel are placed within the mold in an alternating manner to arrive at the stack illustrated in FIGS. 1 and 2.", "The mold 20 is formed from wood or other material to define a mold interior 22 for receiving the stack of hardened structures 14 and steel channel 16 .", "The mold is preferably rectangular but is not limited to a rectangular configuration.", "Nevertheless, the regular shape offered by a rectangular mold lends itself well to producing blocks of building material.", "The heat insulating material 28 if formed according to the formulation described above and is poured from a vessel 26 or otherwise introduced into the interior 22 of the mold 20 to completely fill the mold.", "As seen in FIG. 5, a top portion 24 is placed on the upper surface of the insulating material 28 to define a six-sided structure once the mold is removed.", "It should be noted that while the insulating material 28 is shown being poured from a bucket 26 , this technique is generally performed at a building site and the mass production of blocks according to the present invention will likely progress with the heat insulating material 28 flowing from a piping system or other delivery system.", "Therefore, it should not be presumed under any conditions that the heat insulating material 28 must be poured into the mold 20 .", "In any event, the heat insulating material 28 is allowed to harden and the mold is broken away from the structure formed therein which provides the block 10 as illustrated in FIG. 1 .", "According to another preferred embodiment of the present invention, and with reference to FIG. 4, two steel channels 34 are placed in the bottom of the mold and the heat insulating material 28 is introduced into the interior 22 of the mold as previously described.", "With reference to FIG. 5, once the mold 20 has been filled with heat insulating material 28 , two more steel channels 34 are disposed at upper surface of the heat insulating material 28 .", "As seen in FIG. 5, a top 24 is placed on the steel channels 34 and the flowable heat insulating material 28 is allowed to harden into a hardened heat insulating material 18 as described in the discussion of the formulation.", "It will be apparent that those skilled in the art that the amount of heat insulating material introduced into the mold 28 must be regulated as the material expands when it cools.", "Trial and error or sophisticated density/volume calculations can provide the necessary amount of flowable material that will fill up the mold.", "Further, it is contemplated if the blocks are produced in great numbers, a computer may be employed to feed heat insulating material into the mold 20 in metered amounts sufficient to provide the necessary structure while not overfilling the mold.", "Once the heat insulating material 18 has hardened, the mold may be removed from around the block 10 and the block 10 then used for building material.", "Blocks according to the present invention have many uses and can form mold structures to provide light, heat insulated and heat resistant walls for a building.", "Further, interior wall panels may be placed over the outer steel channels of the blocks illustrated in FIG. 3 .", "Therefore, the present invention provides a lightweight, strong material for construction purposes.", "It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of a broad utility and application.", "Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention.", "Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention.", "The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof." ]
[0001] This application claims priority to U.S. provisional application Ser. No. 60/553,223, filed Mar. 15, 2004, which is incorporated by reference herein, including all Tables, Figures and claims. FIELD OF THE INVENTION [0002] The present invention is directed to lancing devices and methods for use with lancets, for the self-removal of small amounts of body fluid by penetrating a body tissue at a sampling site. BACKGROUND OF THE INVENTION [0003] The following Background of the Invention is intended to aid the reader in understanding the invention and is not admitted to be prior art. [0004] The invention relates to lancet devices for withdrawing blood for diagnostic purposes. The self-removal of small amounts of blood from a finger, forearm or thigh for testing purposes is an often daily necessity among patients having metabolic disorders. This practice enables patients, such as diabetics, to monitor specific analytical values in their blood on a regular basis. [0005] Lancets commonly have a metal needle with one end ground to a point. The posterior part of the lancet needle at the opposite end from the tip is commonly enclosed in a lancet body made of a plastic material (e.g., U.S. Pat. No. 3,358,689). During manufacture the lancet needle is usually positioned in a plastic injection mold and the lancet body injected onto it. [0006] Lancing one's own finger is difficult for some due to the pain sometimes associated with the procedure, and the mental stress experienced by some in performing the procedure. A variety of lancet devices have been developed to aid the patient in lancing themselves. In general, these are spring-actuated devices having a housing with a hole at one end. The lancet is secured inside the device and the device is cocked into a “loaded” position. The orifice is placed against the selected puncture site and the device is fired. When the device is fired, the lancet is thrust forward. The needle is protruded from the orifice and pierces the patient's skin. When the procedure is complete, the patient removes the device from the skin and collects a droplet of blood for testing. The testing is commonly conducted with a personal electronic metabolic monitor, such as those that use either electrochemical or optical test strips. SUMMARY OF THE INVENTION [0007] The present invention is directed to devices for lancing the skin at a selected body site, in order to withdraw a small sample of blood. One embodiment of the present invention is a lancing device that has a housing and an end piece, which has an orifice. A lancet, which has a needle, is secured within the housing and the device is cocked. Next, the end piece is placed against a puncture site and the device is actuated. The lancet needle is rapidly thrust through the orifice and retracted, thus piercing the skin. In one embodiment, there are only five moving pieces used for cocking and firing the device. A spring loaded plunger is disposed within the device, which is cocked using a slider button disposed within the wall of the housing. The plunger has an arming member that engages an arming post disposed within the housing, to hold the plunger in the cocked position. On the plunger is a collar for securely holding the lancet. To fire the device, a release button disposed within the housing wall is depressed. depression of the release button causes the arming member and arming post to disengage and the device to fire. The firing spring thrusts the plunger forward from the retracted (cocked) position during firing, such that a portion of the needle of the lancet protrudes from the orifice. A return spring mounted on the plunger then retracts the needle and returns the plunger to its starting position. The end piece is assembled of a nose and a base. The nose can be rotated about the base, to adjust the depth of needle penetration. The depth adjustment is indicated with markings on the nose and optionally the base. When the device is held in the patient's hand before and during firing, the patient can see the depth setting markings. [0008] In a first aspect, the present invention provides an apparatus for propelling a lancet that can be activated with one hand. The device has a housing, which has proximal and distal portions, interior and exterior surfaces, and an arming post that includes a catch wall. The housing also has one or more alignment guide slots that are disposed on the interior surface, and an orifice at the distal portion. A front piece is removably attached at the distal portion of the housing and has an orifice through which the lancet emerges when the apparatus is activated. The front piece includes a rotatable nose for adjusting the penetration depth of the lancet. A plunger, which has a resting position, a retracted position, and a lancing position, is disposed within the housing. An arming member is integrally and hingeably connected to the plunger and has a step that engages the catch wall of the arming post to hold the plunger in the retracted position. The plunger also has one or more alignment guides that slideably engage the one or more alignment guide slots on the inside wall of the housing. In one embodiment the device is fired by a spring mechanism. The apparatus also has a firing spring for propelling the plunger from the retracted position to the lancing position. The plunger moves parallel to the axis of the housing when propelled. Also attached to the plunger is a return spring for returning the plunger from the lancing position to the resting position. The apparatus also has a depressible release button, which has a portion that engages the arming member and releases the plunger from the retracted position when the release button is depressed. Depressing the release button causes the plunger to move from the retracted position to the lancing position, and the lancet to protrude from the orifice of the front piece. The apparatus also has a slider button that has a portion that engages the plunger, for moving the plunger from the resting position to the retracted position. [0009] In one embodiment of the apparatus, the plunger has a collar for securing the lancet to the plunger. In a further embodiment, the front piece also has a base, which has a hole and is rotatably connected to the nose. The base has base markings for indicating a selected penetration depth of the lancet. The nose is disposed on the base and rotates about the base and has nose markings. The nose markings align with the base markings to indicate the selected penetration depth of the lancet. [0010] In another embodiment, the front piece is removably attached to the housing by a snap-fit attachment. In certain embodiments, the device has five or fewer moving parts. In some embodiments the arming member also has a slide that interacts with the arming post and guides the arming post to the step to secure the plunger in the retracted position. The base markings and nose markings can be disposed on the device to be visible to the user while the apparatus is placed against the skin of the user. [0011] In another aspect, the present invention provides a method of drawing a small blood sample from a subject using a lancing device that can be operated with one hand. The method involves providing an apparatus of the present invention, moving the slider button toward the proximal portion of the housing to engage the step of the arming member with the arming post, and thereby secure the plunger in the retracted position, and depressing the release button to disengage the arming member from the arming post and cause the plunger to be propelled forward to the lancing position and the lancet to pierce the skin of the subject. [0012] In one embodiment, the patient removes the front piece from the housing and secures a lancet to the plunger, and then reattaches the front piece to the housing. This may be followed by a step of rotating the nose to select a penetration depth for the lancet. The method can be carried out with one hand operation. [0013] In another embodiment, when the slider button is moved toward the proximal portion of the housing, the arming member engages the catch wall of the arming post, and the plunger is secured in the retracted position. In still another embodiment, when the plunger is in the retracted position and the release button is depressed, the arming member is freed from the arming post and thereby causes the plunger to be propelled forward and the lancet to protrude from the nose and puncture the skin of the subject. [0014] In a third aspect, the present invention provides an apparatus for propelling a lancet, which can be activated with one hand. In one embodiment, the device has a housing, which has a proximal portion, a distal portion, interior and exterior surfaces, an arming post having a catch wall, one or more alignment guide slots disposed on the interior surface and an orifice at the distal portion. The device also has a front piece that is removably attached at the distal portion of the housing. The front piece has an orifice, through which the lancet emerges when the apparatus is activated, and a means for adjusting the penetration depth of the lancet. A plunger that has a resting position, a retracted position and a lancing position is disposed within the housing. The plunger has a means for arming the plunger, which is integrally and hingeably connected to the plunger. The means for arming the plunger has a means for engaging the catch wall of the arming post and holding the plunger in the retracted position. In certain embodiments, the plunger has a means for aligning the plunger within the housing and for guiding the plunger through the housing as the plunger moves between positions. The plunger also has a means for propelling the plunger from the retracted position to the lancing position, wherein the plunger moves parallel to the axis of the housing when propelled, and a means for returning the plunger from the lancing position to the resting position. In a further embodiment, the device has a means for engaging the arming member and releasing the plunger from the retracted position, and thereby causing the plunger to move from the retracted position to the lancing position, and the lancet to protrude from the orifice of the front piece. In a still further embodiment, the present device has a means for moving the plunger from the resting position to the retracted position. In another embodiment, the plunger also has a collar for securing the lancet to the plunger. [0015] In some embodiments, the front piece also has a base, which has a hole and is rotatably connected to the nose. The base has base markings for indicating a selected penetration depth. In a further embodiment, the means for adjusting the penetration depth of the lance comprises a nose disposed on the base, which rotates about the base. The nose has nose markings that align with the base markings to indicate the selected penetration depth of the lancet. [0016] In still another embodiment, the means for arming the plunger includes a slide, which interacts with the arming post and guides the arming post to a step, which interacts with the arming post to secure the plunger in the retracted position. [0017] In a further embodiment, the base markings and nose markings are disposed on the device to be visible to the user while the apparatus is placed against the skin of the user. [0018] The summary of the invention described above is not limiting and other features and advantages of the invention will be apparent from the following detailed description, as well as from the claims. BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 provides a perspective view of one embodiment of the present invention, having a housing 110 with proximal 112 and distal 114 ends and an end piece 116 . [0020] FIG. 2 provides an exploded view of the device shown in FIG. 1 . [0021] FIG. 3 provides a cut-away perspective view of the device shown in FIG. 1 . The orientation of the plunger 228 , the slider button 236 , release button 242 , firing spring 234 and return spring 250 within the housing is illustrated. [0022] FIG. 4 is a section view of the device shown in FIG. 1 at A-A, illustrating the orientation of the plunger within the housing and the interaction of the alignment guides 232 with the alignment guide slots 216 . [0023] FIG. 5 is a close up of the device shown in FIG. 2 , illustrating the arming post 214 . [0024] FIG. 6A is a perspective view of one embodiment of the release button 242 . [0025] FIG. 6B is a cut-away close-up of the orientation of the release button, the arming post and the arming member 230 when the plunger is in the resting position. [0026] FIG. 7 is a perspective view of one embodiment of the slider button 236 . [0027] FIG. 8 is a perspective view of one embodiment of the nose 120 . [0028] FIG. 9 is a perspective view of one embodiment of the base 122 . [0029] FIG. 10 is an alternative view of the device shown in FIG. 9 . [0030] FIG. 11 illustrates the first step in assembling the front piece 116 . [0031] FIG. 12 illustrates the second step in assembling the front piece. [0032] FIG. 13 is a perspective view of one embodiment of the base, illustrating an orientation key 220 . [0033] FIG. 14 is an alternative perspective view of the device shown in FIG. 13 , illustrating the arrangement of the orientation keys and a detent-receiving groove 226 . [0034] FIG. 15 illustrates the lock 222 , on the exterior of the housing. [0035] FIG. 16 illustrates one embodiment of the plunger showing the attachment of the arming post 230 , the firing spring and the off-set parallel axis of the return spring. [0036] FIG. 17 is a close-up cut-away view of the return spring attachment to the plunger and the slider button. [0037] FIG. 18 is a close-up cut-away view of the firing springs attachment to the plunger and its interaction with the proximal, interior surface of the housing. [0038] FIG. 19 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is in the resting position. Note that neither the firing spring nor the return spring is compressed. [0039] FIG. 20 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is in the process of being cocked. Note that the return spring has been fully compressed and the firing spring is partially compressed. [0040] FIG. 21 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is cocked and the plunger has been moved to the retracted position. Note that both the return spring and the firing spring have been fully compressed. [0041] FIG. 22 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements after the device has been cocked and prior to firing. Note that the return spring has moved the slider button to its original position and the firing spring is fully compressed. [0042] FIG. 23 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements after the device has been fired. Note that the stylet protrudes from the orifice of the device, the firing spring has moved forward with the plunger and the return spring is fully compressed. After firing, the device returns to the configuration shown in FIG. 20 . DETAILED DESCRIPTION [0043] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. [0044] The devices and methods of the present invention enable the easy withdrawal of a droplet of blood from a selected puncture site. The devices allow adjustment of puncture depth and the reduction of pain associated with needle penetration. Additionally, the devices provide for reduced manufacture costs associated with the number of parts required to be manufactured and stocked. Labor costs are reduced reducing the amount of time required to assemble each unit. Reduced assembly time is achieved by first, reducing the number of parts to be assembled, and second, simplifying the part arrangement to make it easier to assemble each device. [0000] Lancet Device [0045] The following discussion relates to those embodiments illustrated in the examples. Of course other embodiments are possible without departing from the scope of this invention. The present invention provides an apparatus for propelling a lancet 246 . The apparatus can be activated with one hand. FIGS. 1-3 illustrate one embodiment of the present device, which has five or fewer moving parts required to cock and fire the device. The device has a housing 110 , which has a proximal portion 112 and a distal portion 114 . The housing also has interior and exterior surfaces ( 210 and 212 , respectively). Disposed on the interior surface of the housing is an arming post 214 , having a catch wall 510 (see FIG. 5 ). One or more alignment guide slots 216 are disposed on the interior surface of the housing. The housing has an orifice 218 at its distal portion. With the exception of the firing 234 and return 236 springs, which will be discussed in greater detail below, all parts of the device are made of injection molded plastic. [0046] In general, a “lancet” for use with a lancing device is a small, disposable device for piercing the skin that has a very short, sharp metal needle and a plastic body. A variety of lancets are currently on the market today. Lancets can be constructed by placing the needle in an injection mould and then filling the mould with plastic. [0047] A front piece 116 can be removably attached to the distal portion of the housing. In one embodiment the front piece has an orifice 118 through which the lancet needle emerges when the apparatus is activated. The front piece can be assembled of two parts, a nose 120 and a base piece 122 which snap together during assembly (see FIGS. 8-14 ). Both the nose and the base have an orifice. When the two pieces are snapped together, the nose orifice (not shown) and the base orifice 1010 align to create the front piece orifice, through which the lancet needle protrudes. [0048] The nose rotates about the base piece, for adjusting the penetration depth of the lancet. As shown in FIG. 8 , the interior surface of the nose has a helical groove 810 and an annular groove 812 . Also disposed on the interior surface of the nose are a plurality of parallel groves 814 with ridges there between, in alignment with the axis of the device. Referring to FIG. 9 , the base has a first detent 910 about which the helical groove slides when the nose is rotated. As the nose is rotated about the base in such a direction that the top of the helical groove moves toward the first detent, the penetration depth is reduced. Conversely, as the nose is rotated about the base in such a direction that the bottom of the helical groove moves toward the first detent, the penetration depth is increased. The depth setting is indicated to the user by the interaction of the parallel grooves 814 on the interior of the nose and a second detent 912 on the base. Additionally, india on the exterior of the nose, corresponding to a location of the first detent along the axis of the helical groove, may indicate the depth setting (see discussion below). The second detent is flexibly disposed on the side of the base. As the nose is rotated about the base, the second detent slides up and over the ridges, and then back into the groves. The second detent can move in and out of the grooves, and over the ridges because it is attached to the base by a flexible arm. Thus, as a ridge makes contact with the second detent, the ridge depresses the second detent. As the ridge moves away from the second detent, the detent returns to its original orientation. As the second detent moves from parallel grove to parallel groove, it makes a click that can be felt or heard by the patient as he adjusts the penetration depth. [0049] The base has a third detent 914 about which the annular groove slides. The interaction of the third detent and the annular groove limits the total amount of the nose about the base. [0050] To assist the patient in accurately selecting a penetration depth, the nose and base may carry indicia that correlate with position of the first detent along the axis of the helical groove. The indicia may take a variety of forms as long as they convey to the patient the increase or decrease of needle penetration associated with a particular nose and base orientation. For example, in FIG. 1 , the nose may carry a series of number and the base a fixed line or arrow, or vice versa. The parts can be arranged so that penetration depth increases as the numbers increase, and the selected penetration depth number aligns with the line or arrow on the base. In another embodiment, bars of increasing height (also shown in FIG. 1 ) or a right-angled triangle can be used to indicate increased penetration depth, instead of numbers. [0051] In certain embodiments, the indicia are disposed on the nose and base such that the depth setting can be seen by the patient when the patient has placed the nose of the device against his skin and is firing the device. [0052] The front piece has a snap-fit attachment to the base. Additionally, the front piece is adapted to fit onto the base in a single orientation. Correct orientation of the end piece is accomplished by the interaction of at least one key 220 on the interior surface of the base and at least one lock 222 on the exterior, distal surface of the housing. The snap-fit attachment is accomplished by mating detents 224 and detent-receiving grooves 226 on the housing and base, respectively (see FIGS. 3 and 13 ). [0053] As illustrated in FIGS. 2 and 3 , a plunger 228 is disposed within the housing. The plunger has three positions, a resting position (see FIG. 19 ), a retracted position (see FIG. 22 ), and a lancing position (see FIG. 23 ). These positions will be discussed in greater detail below. [0054] Referring to FIGS. 2, 3 , 6 B and 16 , the plunger has an arming member 230 that is integrally and hingeably connected to the plunger. The plunger and the arming member are injection molded as one piece of substantially rigid plastic. On the end opposite to the connection of the arming member and the plunger, the arming member has a step 1610 (see FIGS. 6B and 16 ). The step engages the catch wall 510 of the arming post to hold the plunger in the retracted position (see FIG. 21 , no. 2110 ). The arming member also has a slide 1612 (see FIGS. 6B , 16 , 19 and 20 ). As the plunger is moved to the retracted position, the arming post interacts with the slide to press the arming member downward ( FIG. 19 , no. 1910 ). The slide guides the arming post to the step to secure the plunger in the retracted position ( FIG. 20 ). [0055] The plunger also has one or more alignment guides 232 that slideably engage the one or more alignment guide slots 216 (see FIGS. 2-4 and 6 B). The interaction between the alignment guides with the guide slots is illustrated in cross-section A-A ( FIG. 4 ). The interaction of the alignment guides and the alignment guide slots prevents torque and vibration about the axis of the plunger during operation, to reduce pain to the patient. [0056] As illustrated in the Figures, a firing spring 234 , having first and second ends, is slideably attached to the rear end 1614 of the plunger. The first end of the spring may be attached to the plunger by one or more tangs 1616 . The plunger may have a compression ring 1618 , against which the first end of the spring may press. At its second end, the firing spring presses against the interior proximal end of the housing (see FIG. 18 ). When the plunger is moved to the retracted position, the firing spring is compressed, causing an increase in its spring energy. When the device is fired, the firing spring releases the stored energy an propels the plunger from the retracted position to the lancing position. As the plunger is thrust forward from the retracted position to the lancing position, it moves parallel to the axis of the housing. [0057] The plunger has a return spring 250 for returning the plunger from the lancing position to the resting position. As illustrated in FIG. 17 , the return spring is attached to the plunger by a collar post 1710 on the front of the compression ring. The return spring engages a slider button 236 (see FIGS. 2 and 7 ). The slider button is slideably disposed in the housing and moves the plunger from the resting position to the retracted position as it is moved. A portion of the slider button, such as a slider collar 238 , engages the plunger, for moving the plunger from the resting position to the retracted position. The slider collar wraps around the plunger and on the bottom of the slider collar is a spring post 240 . The return spring is attached to the spring post at one end and the collar post at the other end. To cock and arm the device, the patient slides the slider button toward the proximal end of the housing. The slider collar depresses the return spring and pushes the plunger to the retracted position either by pushing in a proximal direction on the collar post or on the compression ring (see FIG. 20 ). As previously discussed, the step 1610 engages the stop post and holds the plunger in the retracted position. When the device in the retracted position, the return spring is compressed between the collar post and the spring post (see FIG. 21, 2112 ). After the device is placed into the retracted position, the return spring pushes the slider in a distal direction, to its start position (see FIG. 22, 2210 ). When the release button is depressed, the plunger is propelled forward by the firing spring, and the return spring becomes compressed between the collar post and the spring post (see FIGS. 23, 2310 and 2314 ). The return spring moves the plunger back to the resting position, from the lancing position. As the plunger is returned to the resting position, the exposed needle is retracted through the orifice (compare FIGS. 23 and 19 ). [0058] A depressible release button 242 is mounted in the housing, near the proximal end (see FIGS. 2, 3 , 6 A and 6 B). A cantilevered arm 610 having a detent 612 is integrally attached to the bottom of the release button. The arm and detent fit snuggly into a groove 618 in the housing wall. The groove is adapted to snuggly hold the arm and detent. The release button extends towards the proximal end of the device and over the arming post 214 (see FIG. 6B ). The release button also has a release post 614 , which optionally has a release detent 616 . As illustrated in FIGS. 6 B and 19 - 22 , the release post engages the arming member. When the release button is depressed, the release post pushes the arming member downward, such that the step is disengaged from the arming post 2314 . As a result, the plunger is released from the retracted position and is thrust forward to the lancing position, by the firing spring 2312 . As the plunger arrives in the lancing position, the lancet needle protrudes from the orifice of the front piece and pierces the skin of the patient. [0059] Referring to FIGS. 2, 3 and 6 B, the plunger has a collar 244 , at its distal end, for holding the lancet 246 in position for lancing the skin. The collar is integrally attached to the plunger because it is injection molded as one piece. The collar is adapted to be slightly flexible such that the body of a lancet can be slid into the collar, but the collar still retains a firm hold on the lancet body. [0060] Another embodiment of the present device is an apparatus for propelling a lancet, which can be activated with one hand and has five or fewer moving parts for cocking and firing the device. In this embodiment, the device has a housing, having a proximal portion, a distal portion, interior and exterior surfaces, an arming post having a catch wall, one or more alignment guide slots disposed on the interior surface and an orifice at the distal portion. A front piece removably attached at the distal portion of the housing. The front piece has an orifice through which the lancet emerges when the apparatus is activated. The front piece also has a means for adjusting the penetration depth of the lancet. [0061] Disposed within the housing is a plunger having a resting position, a retracted position, and a lancing position. The plunger has arming mans, such as a biasing means, which is integrally and hingeably connected to the it. The means for arming the plunger has a means for engaging the catch wall of the arming post and holding the plunger in the retracted position. [0062] The present device has a means for aligning the plunger within the housing and for guiding the plunger through the housing as the plunger moves between positions. The means for aligning and guiding the plunger prevents torque and vibrations when the device is actuated, which would cause increased pain to the patient. [0063] The present device includes a means for moving the plunger from the resting position to the retracted position, to cock the device. After the device has been cocked, it can be fired. [0064] A means for propelling the plunger from the retracted position to the lancing position is attached to the proximal end of the plunger. When the plunger moves from one position to another and when it is propelled, it moves parallel to the axis of the housing. The device also has a means for engaging the arming member and releasing the plunger from the retracted position, and thereby causing the plunger to move from the retracted position to the lancing position. When the plunger moves from the retracted position to the lancing position (i.e., fires), the lancet protrudes from the orifice of the front piece and pierces the patient's skin. [0065] The plunger includes a means for returning the plunger from the lancing position to the resting position. When the plunger returns from the lancing position to the resting position, the lancet is retracted back into the device. If desired, the patient may replace the used lancet with a new one, and re-lance himself. [0066] The lancet is secured to the plunger by a collar integrally attached to the distal end of the plunger. The plunger, the collar and the arming means are injection molded as one piece, of substantially rigid plastic. [0067] In a further embodiment, the front piece has a base that having a hole and is rotatably connected to the nose. The base has base markings for indicating a selected penetration depth. The means for adjusting the penetration depth of the lance comprises a nose disposed on the base that rotates about the base. The nose has nose markings that align with the base markings, to indicate the selected penetration depth of the lancet. These markings can be seen by the patient when they have placed the nose against their skin and are firing the device. [0068] In another embodiment of the present device, the device has five or fewer moving parts for cocking and firing the device. The moving parts may be a plunger, a firing spring, a return spring, a slider button and a release button. [0069] In yet another embodiment, the apparatus has a means for arming the plunger. The means for arming the plunger has a slide, which interacts with the arming post and guides the arming post to a step which interacts with an arming post to secure the plunger in the retracted position. [0000] Methods of Use [0070] The present invention also provides a method of drawing a blood sample from a subject using a lancing device that can be operated with one hand. In one embodiment of the present method, the patient provides the present device in the resting position ( FIG. 19 ) and then cocks the device by moving the slider button toward the proximal portion of the housing. As the patient does this, the step of the arming member engages the arming post, and thereby secure the plunger in the retracted position (see FIG. 21 ). The patient then places the nose of the device against the selected puncture site and depresses the release button. When the release button is depressed, the arming member is disengaged from the arming post, whereby the plunger is propelled forward to the lancing position and the lancet pierces the skin of the subject ( FIG. 23 ). [0071] In one embodiment, the method includes the step of removing the front piece from the housing and securing a lancet to the plunger, and reattaching the front piece to the housing. The patient may then rotate the nose to select a penetration depth for the lancet. [0072] In certain embodiments of the present method, the steps of cocking and firing the device are carried out with one handed operation. [0073] In another embodiment, the method includes the step of moving the slider button toward the proximal portion of the housing, whereby the arming member engages the catch wall of the arming post, and the plunger is secured in the retracted position. When the plunger is in the retracted position, the release button is depressed, causing the arming member to be freed from the arming post thereby causing the plunger to be propelled forward and the lancet to protrude from the nose and puncture the skin of the subject. [0074] The invention illustratively described herein may be practiced in the absence of any element or elements, limitation or limitations that are not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by various embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. [0075] The contents of the articles, patents, and patent applications, and all other documents and electronically available information mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. Applicants reserve the right to physically incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents.
The present invention is directed to spring-activated devices and methods for lancing the skin to obtain a small amount of blood for metabolic testing. In one embodiment, the depth penetration of the lancet needle can be seen by the patient during lancing the skin. In another embodiment, the device has only five moving parts for cocking and firing, a plunger, two springs, a slider and a button. In order to reduce manufacturing costs, the number of parts used in the device has been reduced and their configuration has been simplified to reduce construction time, and thereby save on labor costs.
Briefly summarize the invention's components and working principles as described in the document.
[ "[0001] This application claims priority to U.S. provisional application Ser.", "No. 60/553,223, filed Mar. 15, 2004, which is incorporated by reference herein, including all Tables, Figures and claims.", "FIELD OF THE INVENTION [0002] The present invention is directed to lancing devices and methods for use with lancets, for the self-removal of small amounts of body fluid by penetrating a body tissue at a sampling site.", "BACKGROUND OF THE INVENTION [0003] The following Background of the Invention is intended to aid the reader in understanding the invention and is not admitted to be prior art.", "[0004] The invention relates to lancet devices for withdrawing blood for diagnostic purposes.", "The self-removal of small amounts of blood from a finger, forearm or thigh for testing purposes is an often daily necessity among patients having metabolic disorders.", "This practice enables patients, such as diabetics, to monitor specific analytical values in their blood on a regular basis.", "[0005] Lancets commonly have a metal needle with one end ground to a point.", "The posterior part of the lancet needle at the opposite end from the tip is commonly enclosed in a lancet body made of a plastic material (e.g., U.S. Pat. No. 3,358,689).", "During manufacture the lancet needle is usually positioned in a plastic injection mold and the lancet body injected onto it.", "[0006] Lancing one's own finger is difficult for some due to the pain sometimes associated with the procedure, and the mental stress experienced by some in performing the procedure.", "A variety of lancet devices have been developed to aid the patient in lancing themselves.", "In general, these are spring-actuated devices having a housing with a hole at one end.", "The lancet is secured inside the device and the device is cocked into a “loaded”", "position.", "The orifice is placed against the selected puncture site and the device is fired.", "When the device is fired, the lancet is thrust forward.", "The needle is protruded from the orifice and pierces the patient's skin.", "When the procedure is complete, the patient removes the device from the skin and collects a droplet of blood for testing.", "The testing is commonly conducted with a personal electronic metabolic monitor, such as those that use either electrochemical or optical test strips.", "SUMMARY OF THE INVENTION [0007] The present invention is directed to devices for lancing the skin at a selected body site, in order to withdraw a small sample of blood.", "One embodiment of the present invention is a lancing device that has a housing and an end piece, which has an orifice.", "A lancet, which has a needle, is secured within the housing and the device is cocked.", "Next, the end piece is placed against a puncture site and the device is actuated.", "The lancet needle is rapidly thrust through the orifice and retracted, thus piercing the skin.", "In one embodiment, there are only five moving pieces used for cocking and firing the device.", "A spring loaded plunger is disposed within the device, which is cocked using a slider button disposed within the wall of the housing.", "The plunger has an arming member that engages an arming post disposed within the housing, to hold the plunger in the cocked position.", "On the plunger is a collar for securely holding the lancet.", "To fire the device, a release button disposed within the housing wall is depressed.", "depression of the release button causes the arming member and arming post to disengage and the device to fire.", "The firing spring thrusts the plunger forward from the retracted (cocked) position during firing, such that a portion of the needle of the lancet protrudes from the orifice.", "A return spring mounted on the plunger then retracts the needle and returns the plunger to its starting position.", "The end piece is assembled of a nose and a base.", "The nose can be rotated about the base, to adjust the depth of needle penetration.", "The depth adjustment is indicated with markings on the nose and optionally the base.", "When the device is held in the patient's hand before and during firing, the patient can see the depth setting markings.", "[0008] In a first aspect, the present invention provides an apparatus for propelling a lancet that can be activated with one hand.", "The device has a housing, which has proximal and distal portions, interior and exterior surfaces, and an arming post that includes a catch wall.", "The housing also has one or more alignment guide slots that are disposed on the interior surface, and an orifice at the distal portion.", "A front piece is removably attached at the distal portion of the housing and has an orifice through which the lancet emerges when the apparatus is activated.", "The front piece includes a rotatable nose for adjusting the penetration depth of the lancet.", "A plunger, which has a resting position, a retracted position, and a lancing position, is disposed within the housing.", "An arming member is integrally and hingeably connected to the plunger and has a step that engages the catch wall of the arming post to hold the plunger in the retracted position.", "The plunger also has one or more alignment guides that slideably engage the one or more alignment guide slots on the inside wall of the housing.", "In one embodiment the device is fired by a spring mechanism.", "The apparatus also has a firing spring for propelling the plunger from the retracted position to the lancing position.", "The plunger moves parallel to the axis of the housing when propelled.", "Also attached to the plunger is a return spring for returning the plunger from the lancing position to the resting position.", "The apparatus also has a depressible release button, which has a portion that engages the arming member and releases the plunger from the retracted position when the release button is depressed.", "Depressing the release button causes the plunger to move from the retracted position to the lancing position, and the lancet to protrude from the orifice of the front piece.", "The apparatus also has a slider button that has a portion that engages the plunger, for moving the plunger from the resting position to the retracted position.", "[0009] In one embodiment of the apparatus, the plunger has a collar for securing the lancet to the plunger.", "In a further embodiment, the front piece also has a base, which has a hole and is rotatably connected to the nose.", "The base has base markings for indicating a selected penetration depth of the lancet.", "The nose is disposed on the base and rotates about the base and has nose markings.", "The nose markings align with the base markings to indicate the selected penetration depth of the lancet.", "[0010] In another embodiment, the front piece is removably attached to the housing by a snap-fit attachment.", "In certain embodiments, the device has five or fewer moving parts.", "In some embodiments the arming member also has a slide that interacts with the arming post and guides the arming post to the step to secure the plunger in the retracted position.", "The base markings and nose markings can be disposed on the device to be visible to the user while the apparatus is placed against the skin of the user.", "[0011] In another aspect, the present invention provides a method of drawing a small blood sample from a subject using a lancing device that can be operated with one hand.", "The method involves providing an apparatus of the present invention, moving the slider button toward the proximal portion of the housing to engage the step of the arming member with the arming post, and thereby secure the plunger in the retracted position, and depressing the release button to disengage the arming member from the arming post and cause the plunger to be propelled forward to the lancing position and the lancet to pierce the skin of the subject.", "[0012] In one embodiment, the patient removes the front piece from the housing and secures a lancet to the plunger, and then reattaches the front piece to the housing.", "This may be followed by a step of rotating the nose to select a penetration depth for the lancet.", "The method can be carried out with one hand operation.", "[0013] In another embodiment, when the slider button is moved toward the proximal portion of the housing, the arming member engages the catch wall of the arming post, and the plunger is secured in the retracted position.", "In still another embodiment, when the plunger is in the retracted position and the release button is depressed, the arming member is freed from the arming post and thereby causes the plunger to be propelled forward and the lancet to protrude from the nose and puncture the skin of the subject.", "[0014] In a third aspect, the present invention provides an apparatus for propelling a lancet, which can be activated with one hand.", "In one embodiment, the device has a housing, which has a proximal portion, a distal portion, interior and exterior surfaces, an arming post having a catch wall, one or more alignment guide slots disposed on the interior surface and an orifice at the distal portion.", "The device also has a front piece that is removably attached at the distal portion of the housing.", "The front piece has an orifice, through which the lancet emerges when the apparatus is activated, and a means for adjusting the penetration depth of the lancet.", "A plunger that has a resting position, a retracted position and a lancing position is disposed within the housing.", "The plunger has a means for arming the plunger, which is integrally and hingeably connected to the plunger.", "The means for arming the plunger has a means for engaging the catch wall of the arming post and holding the plunger in the retracted position.", "In certain embodiments, the plunger has a means for aligning the plunger within the housing and for guiding the plunger through the housing as the plunger moves between positions.", "The plunger also has a means for propelling the plunger from the retracted position to the lancing position, wherein the plunger moves parallel to the axis of the housing when propelled, and a means for returning the plunger from the lancing position to the resting position.", "In a further embodiment, the device has a means for engaging the arming member and releasing the plunger from the retracted position, and thereby causing the plunger to move from the retracted position to the lancing position, and the lancet to protrude from the orifice of the front piece.", "In a still further embodiment, the present device has a means for moving the plunger from the resting position to the retracted position.", "In another embodiment, the plunger also has a collar for securing the lancet to the plunger.", "[0015] In some embodiments, the front piece also has a base, which has a hole and is rotatably connected to the nose.", "The base has base markings for indicating a selected penetration depth.", "In a further embodiment, the means for adjusting the penetration depth of the lance comprises a nose disposed on the base, which rotates about the base.", "The nose has nose markings that align with the base markings to indicate the selected penetration depth of the lancet.", "[0016] In still another embodiment, the means for arming the plunger includes a slide, which interacts with the arming post and guides the arming post to a step, which interacts with the arming post to secure the plunger in the retracted position.", "[0017] In a further embodiment, the base markings and nose markings are disposed on the device to be visible to the user while the apparatus is placed against the skin of the user.", "[0018] The summary of the invention described above is not limiting and other features and advantages of the invention will be apparent from the following detailed description, as well as from the claims.", "BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 provides a perspective view of one embodiment of the present invention, having a housing 110 with proximal 112 and distal 114 ends and an end piece 116 .", "[0020] FIG. 2 provides an exploded view of the device shown in FIG. 1 .", "[0021] FIG. 3 provides a cut-away perspective view of the device shown in FIG. 1 .", "The orientation of the plunger 228 , the slider button 236 , release button 242 , firing spring 234 and return spring 250 within the housing is illustrated.", "[0022] FIG. 4 is a section view of the device shown in FIG. 1 at A-A, illustrating the orientation of the plunger within the housing and the interaction of the alignment guides 232 with the alignment guide slots 216 .", "[0023] FIG. 5 is a close up of the device shown in FIG. 2 , illustrating the arming post 214 .", "[0024] FIG. 6A is a perspective view of one embodiment of the release button 242 .", "[0025] FIG. 6B is a cut-away close-up of the orientation of the release button, the arming post and the arming member 230 when the plunger is in the resting position.", "[0026] FIG. 7 is a perspective view of one embodiment of the slider button 236 .", "[0027] FIG. 8 is a perspective view of one embodiment of the nose 120 .", "[0028] FIG. 9 is a perspective view of one embodiment of the base 122 .", "[0029] FIG. 10 is an alternative view of the device shown in FIG. 9 .", "[0030] FIG. 11 illustrates the first step in assembling the front piece 116 .", "[0031] FIG. 12 illustrates the second step in assembling the front piece.", "[0032] FIG. 13 is a perspective view of one embodiment of the base, illustrating an orientation key 220 .", "[0033] FIG. 14 is an alternative perspective view of the device shown in FIG. 13 , illustrating the arrangement of the orientation keys and a detent-receiving groove 226 .", "[0034] FIG. 15 illustrates the lock 222 , on the exterior of the housing.", "[0035] FIG. 16 illustrates one embodiment of the plunger showing the attachment of the arming post 230 , the firing spring and the off-set parallel axis of the return spring.", "[0036] FIG. 17 is a close-up cut-away view of the return spring attachment to the plunger and the slider button.", "[0037] FIG. 18 is a close-up cut-away view of the firing springs attachment to the plunger and its interaction with the proximal, interior surface of the housing.", "[0038] FIG. 19 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is in the resting position.", "Note that neither the firing spring nor the return spring is compressed.", "[0039] FIG. 20 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is in the process of being cocked.", "Note that the return spring has been fully compressed and the firing spring is partially compressed.", "[0040] FIG. 21 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements when the device is cocked and the plunger has been moved to the retracted position.", "Note that both the return spring and the firing spring have been fully compressed.", "[0041] FIG. 22 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements after the device has been cocked and prior to firing.", "Note that the return spring has moved the slider button to its original position and the firing spring is fully compressed.", "[0042] FIG. 23 is a cutaway view of the device shown in FIG. 1 , illustrating the arrangement of elements after the device has been fired.", "Note that the stylet protrudes from the orifice of the device, the firing spring has moved forward with the plunger and the return spring is fully compressed.", "After firing, the device returns to the configuration shown in FIG. 20 .", "DETAILED DESCRIPTION [0043] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced.", "It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.", "[0044] The devices and methods of the present invention enable the easy withdrawal of a droplet of blood from a selected puncture site.", "The devices allow adjustment of puncture depth and the reduction of pain associated with needle penetration.", "Additionally, the devices provide for reduced manufacture costs associated with the number of parts required to be manufactured and stocked.", "Labor costs are reduced reducing the amount of time required to assemble each unit.", "Reduced assembly time is achieved by first, reducing the number of parts to be assembled, and second, simplifying the part arrangement to make it easier to assemble each device.", "[0000] Lancet Device [0045] The following discussion relates to those embodiments illustrated in the examples.", "Of course other embodiments are possible without departing from the scope of this invention.", "The present invention provides an apparatus for propelling a lancet 246 .", "The apparatus can be activated with one hand.", "FIGS. 1-3 illustrate one embodiment of the present device, which has five or fewer moving parts required to cock and fire the device.", "The device has a housing 110 , which has a proximal portion 112 and a distal portion 114 .", "The housing also has interior and exterior surfaces ( 210 and 212 , respectively).", "Disposed on the interior surface of the housing is an arming post 214 , having a catch wall 510 (see FIG. 5 ).", "One or more alignment guide slots 216 are disposed on the interior surface of the housing.", "The housing has an orifice 218 at its distal portion.", "With the exception of the firing 234 and return 236 springs, which will be discussed in greater detail below, all parts of the device are made of injection molded plastic.", "[0046] In general, a “lancet”", "for use with a lancing device is a small, disposable device for piercing the skin that has a very short, sharp metal needle and a plastic body.", "A variety of lancets are currently on the market today.", "Lancets can be constructed by placing the needle in an injection mould and then filling the mould with plastic.", "[0047] A front piece 116 can be removably attached to the distal portion of the housing.", "In one embodiment the front piece has an orifice 118 through which the lancet needle emerges when the apparatus is activated.", "The front piece can be assembled of two parts, a nose 120 and a base piece 122 which snap together during assembly (see FIGS. 8-14 ).", "Both the nose and the base have an orifice.", "When the two pieces are snapped together, the nose orifice (not shown) and the base orifice 1010 align to create the front piece orifice, through which the lancet needle protrudes.", "[0048] The nose rotates about the base piece, for adjusting the penetration depth of the lancet.", "As shown in FIG. 8 , the interior surface of the nose has a helical groove 810 and an annular groove 812 .", "Also disposed on the interior surface of the nose are a plurality of parallel groves 814 with ridges there between, in alignment with the axis of the device.", "Referring to FIG. 9 , the base has a first detent 910 about which the helical groove slides when the nose is rotated.", "As the nose is rotated about the base in such a direction that the top of the helical groove moves toward the first detent, the penetration depth is reduced.", "Conversely, as the nose is rotated about the base in such a direction that the bottom of the helical groove moves toward the first detent, the penetration depth is increased.", "The depth setting is indicated to the user by the interaction of the parallel grooves 814 on the interior of the nose and a second detent 912 on the base.", "Additionally, india on the exterior of the nose, corresponding to a location of the first detent along the axis of the helical groove, may indicate the depth setting (see discussion below).", "The second detent is flexibly disposed on the side of the base.", "As the nose is rotated about the base, the second detent slides up and over the ridges, and then back into the groves.", "The second detent can move in and out of the grooves, and over the ridges because it is attached to the base by a flexible arm.", "Thus, as a ridge makes contact with the second detent, the ridge depresses the second detent.", "As the ridge moves away from the second detent, the detent returns to its original orientation.", "As the second detent moves from parallel grove to parallel groove, it makes a click that can be felt or heard by the patient as he adjusts the penetration depth.", "[0049] The base has a third detent 914 about which the annular groove slides.", "The interaction of the third detent and the annular groove limits the total amount of the nose about the base.", "[0050] To assist the patient in accurately selecting a penetration depth, the nose and base may carry indicia that correlate with position of the first detent along the axis of the helical groove.", "The indicia may take a variety of forms as long as they convey to the patient the increase or decrease of needle penetration associated with a particular nose and base orientation.", "For example, in FIG. 1 , the nose may carry a series of number and the base a fixed line or arrow, or vice versa.", "The parts can be arranged so that penetration depth increases as the numbers increase, and the selected penetration depth number aligns with the line or arrow on the base.", "In another embodiment, bars of increasing height (also shown in FIG. 1 ) or a right-angled triangle can be used to indicate increased penetration depth, instead of numbers.", "[0051] In certain embodiments, the indicia are disposed on the nose and base such that the depth setting can be seen by the patient when the patient has placed the nose of the device against his skin and is firing the device.", "[0052] The front piece has a snap-fit attachment to the base.", "Additionally, the front piece is adapted to fit onto the base in a single orientation.", "Correct orientation of the end piece is accomplished by the interaction of at least one key 220 on the interior surface of the base and at least one lock 222 on the exterior, distal surface of the housing.", "The snap-fit attachment is accomplished by mating detents 224 and detent-receiving grooves 226 on the housing and base, respectively (see FIGS. 3 and 13 ).", "[0053] As illustrated in FIGS. 2 and 3 , a plunger 228 is disposed within the housing.", "The plunger has three positions, a resting position (see FIG. 19 ), a retracted position (see FIG. 22 ), and a lancing position (see FIG. 23 ).", "These positions will be discussed in greater detail below.", "[0054] Referring to FIGS. 2, 3 , 6 B and 16 , the plunger has an arming member 230 that is integrally and hingeably connected to the plunger.", "The plunger and the arming member are injection molded as one piece of substantially rigid plastic.", "On the end opposite to the connection of the arming member and the plunger, the arming member has a step 1610 (see FIGS. 6B and 16 ).", "The step engages the catch wall 510 of the arming post to hold the plunger in the retracted position (see FIG. 21 , no. 2110 ).", "The arming member also has a slide 1612 (see FIGS. 6B , 16 , 19 and 20 ).", "As the plunger is moved to the retracted position, the arming post interacts with the slide to press the arming member downward ( FIG. 19 , no. 1910 ).", "The slide guides the arming post to the step to secure the plunger in the retracted position ( FIG. 20 ).", "[0055] The plunger also has one or more alignment guides 232 that slideably engage the one or more alignment guide slots 216 (see FIGS. 2-4 and 6 B).", "The interaction between the alignment guides with the guide slots is illustrated in cross-section A-A ( FIG. 4 ).", "The interaction of the alignment guides and the alignment guide slots prevents torque and vibration about the axis of the plunger during operation, to reduce pain to the patient.", "[0056] As illustrated in the Figures, a firing spring 234 , having first and second ends, is slideably attached to the rear end 1614 of the plunger.", "The first end of the spring may be attached to the plunger by one or more tangs 1616 .", "The plunger may have a compression ring 1618 , against which the first end of the spring may press.", "At its second end, the firing spring presses against the interior proximal end of the housing (see FIG. 18 ).", "When the plunger is moved to the retracted position, the firing spring is compressed, causing an increase in its spring energy.", "When the device is fired, the firing spring releases the stored energy an propels the plunger from the retracted position to the lancing position.", "As the plunger is thrust forward from the retracted position to the lancing position, it moves parallel to the axis of the housing.", "[0057] The plunger has a return spring 250 for returning the plunger from the lancing position to the resting position.", "As illustrated in FIG. 17 , the return spring is attached to the plunger by a collar post 1710 on the front of the compression ring.", "The return spring engages a slider button 236 (see FIGS. 2 and 7 ).", "The slider button is slideably disposed in the housing and moves the plunger from the resting position to the retracted position as it is moved.", "A portion of the slider button, such as a slider collar 238 , engages the plunger, for moving the plunger from the resting position to the retracted position.", "The slider collar wraps around the plunger and on the bottom of the slider collar is a spring post 240 .", "The return spring is attached to the spring post at one end and the collar post at the other end.", "To cock and arm the device, the patient slides the slider button toward the proximal end of the housing.", "The slider collar depresses the return spring and pushes the plunger to the retracted position either by pushing in a proximal direction on the collar post or on the compression ring (see FIG. 20 ).", "As previously discussed, the step 1610 engages the stop post and holds the plunger in the retracted position.", "When the device in the retracted position, the return spring is compressed between the collar post and the spring post (see FIG. 21, 2112 ).", "After the device is placed into the retracted position, the return spring pushes the slider in a distal direction, to its start position (see FIG. 22, 2210 ).", "When the release button is depressed, the plunger is propelled forward by the firing spring, and the return spring becomes compressed between the collar post and the spring post (see FIGS. 23, 2310 and 2314 ).", "The return spring moves the plunger back to the resting position, from the lancing position.", "As the plunger is returned to the resting position, the exposed needle is retracted through the orifice (compare FIGS. 23 and 19 ).", "[0058] A depressible release button 242 is mounted in the housing, near the proximal end (see FIGS. 2, 3 , 6 A and 6 B).", "A cantilevered arm 610 having a detent 612 is integrally attached to the bottom of the release button.", "The arm and detent fit snuggly into a groove 618 in the housing wall.", "The groove is adapted to snuggly hold the arm and detent.", "The release button extends towards the proximal end of the device and over the arming post 214 (see FIG. 6B ).", "The release button also has a release post 614 , which optionally has a release detent 616 .", "As illustrated in FIGS. 6 B and 19 - 22 , the release post engages the arming member.", "When the release button is depressed, the release post pushes the arming member downward, such that the step is disengaged from the arming post 2314 .", "As a result, the plunger is released from the retracted position and is thrust forward to the lancing position, by the firing spring 2312 .", "As the plunger arrives in the lancing position, the lancet needle protrudes from the orifice of the front piece and pierces the skin of the patient.", "[0059] Referring to FIGS. 2, 3 and 6 B, the plunger has a collar 244 , at its distal end, for holding the lancet 246 in position for lancing the skin.", "The collar is integrally attached to the plunger because it is injection molded as one piece.", "The collar is adapted to be slightly flexible such that the body of a lancet can be slid into the collar, but the collar still retains a firm hold on the lancet body.", "[0060] Another embodiment of the present device is an apparatus for propelling a lancet, which can be activated with one hand and has five or fewer moving parts for cocking and firing the device.", "In this embodiment, the device has a housing, having a proximal portion, a distal portion, interior and exterior surfaces, an arming post having a catch wall, one or more alignment guide slots disposed on the interior surface and an orifice at the distal portion.", "A front piece removably attached at the distal portion of the housing.", "The front piece has an orifice through which the lancet emerges when the apparatus is activated.", "The front piece also has a means for adjusting the penetration depth of the lancet.", "[0061] Disposed within the housing is a plunger having a resting position, a retracted position, and a lancing position.", "The plunger has arming mans, such as a biasing means, which is integrally and hingeably connected to the it.", "The means for arming the plunger has a means for engaging the catch wall of the arming post and holding the plunger in the retracted position.", "[0062] The present device has a means for aligning the plunger within the housing and for guiding the plunger through the housing as the plunger moves between positions.", "The means for aligning and guiding the plunger prevents torque and vibrations when the device is actuated, which would cause increased pain to the patient.", "[0063] The present device includes a means for moving the plunger from the resting position to the retracted position, to cock the device.", "After the device has been cocked, it can be fired.", "[0064] A means for propelling the plunger from the retracted position to the lancing position is attached to the proximal end of the plunger.", "When the plunger moves from one position to another and when it is propelled, it moves parallel to the axis of the housing.", "The device also has a means for engaging the arming member and releasing the plunger from the retracted position, and thereby causing the plunger to move from the retracted position to the lancing position.", "When the plunger moves from the retracted position to the lancing position (i.e., fires), the lancet protrudes from the orifice of the front piece and pierces the patient's skin.", "[0065] The plunger includes a means for returning the plunger from the lancing position to the resting position.", "When the plunger returns from the lancing position to the resting position, the lancet is retracted back into the device.", "If desired, the patient may replace the used lancet with a new one, and re-lance himself.", "[0066] The lancet is secured to the plunger by a collar integrally attached to the distal end of the plunger.", "The plunger, the collar and the arming means are injection molded as one piece, of substantially rigid plastic.", "[0067] In a further embodiment, the front piece has a base that having a hole and is rotatably connected to the nose.", "The base has base markings for indicating a selected penetration depth.", "The means for adjusting the penetration depth of the lance comprises a nose disposed on the base that rotates about the base.", "The nose has nose markings that align with the base markings, to indicate the selected penetration depth of the lancet.", "These markings can be seen by the patient when they have placed the nose against their skin and are firing the device.", "[0068] In another embodiment of the present device, the device has five or fewer moving parts for cocking and firing the device.", "The moving parts may be a plunger, a firing spring, a return spring, a slider button and a release button.", "[0069] In yet another embodiment, the apparatus has a means for arming the plunger.", "The means for arming the plunger has a slide, which interacts with the arming post and guides the arming post to a step which interacts with an arming post to secure the plunger in the retracted position.", "[0000] Methods of Use [0070] The present invention also provides a method of drawing a blood sample from a subject using a lancing device that can be operated with one hand.", "In one embodiment of the present method, the patient provides the present device in the resting position ( FIG. 19 ) and then cocks the device by moving the slider button toward the proximal portion of the housing.", "As the patient does this, the step of the arming member engages the arming post, and thereby secure the plunger in the retracted position (see FIG. 21 ).", "The patient then places the nose of the device against the selected puncture site and depresses the release button.", "When the release button is depressed, the arming member is disengaged from the arming post, whereby the plunger is propelled forward to the lancing position and the lancet pierces the skin of the subject ( FIG. 23 ).", "[0071] In one embodiment, the method includes the step of removing the front piece from the housing and securing a lancet to the plunger, and reattaching the front piece to the housing.", "The patient may then rotate the nose to select a penetration depth for the lancet.", "[0072] In certain embodiments of the present method, the steps of cocking and firing the device are carried out with one handed operation.", "[0073] In another embodiment, the method includes the step of moving the slider button toward the proximal portion of the housing, whereby the arming member engages the catch wall of the arming post, and the plunger is secured in the retracted position.", "When the plunger is in the retracted position, the release button is depressed, causing the arming member to be freed from the arming post thereby causing the plunger to be propelled forward and the lancet to protrude from the nose and puncture the skin of the subject.", "[0074] The invention illustratively described herein may be practiced in the absence of any element or elements, limitation or limitations that are not specifically disclosed herein.", "The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed.", "Thus, it should be understood that although the present invention has been specifically disclosed by various embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.", "[0075] The contents of the articles, patents, and patent applications, and all other documents and electronically available information mentioned or cited herein, are hereby incorporated by reference in their entirety to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.", "Applicants reserve the right to physically incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents." ]
This is a division of application Ser. No. 930,457 filed Aug. 2, 1978 now U.S. Pat. No. 4,230,293. BACKGROUND OF THE INVENTION Present day airplanes utilize an efficient structure that is lightweight for a given loading. Composite materials are recognized as offering a potential for an even more efficient, weight wise, structure. In U.S. Pat. No. 2,817,484 to Stenzel it shows a fuselage type structure with spirally wound hollow metal members, and longitudinal members both bonded together with a bonding agent. SUMMARY OF THE INVENTION An inner and an outer skin of filaments wound circumferentially and longitudinally each have facing crisscrossing helically wound filaments in reinforcing strips. The skins are spaced apart with reinforcing plugs located to contact the strips at the intersections. The plugs have inward extending fastener sockets and the inner skin and reinforcing strips have contiguous openings to permit entry into the sockets. Panels extend between adjacent plugs and the two skins and all the components are integrally joined with resins into a composite structure. Frames for support of openings through the structure are integrally located within the composite. DESCRIPTION OF THE DRAWINGS FIG. 1 shows a fragmented perspective view of the composite structure of this invention with parts broken away to show the buildup of the composite. FIG. 2 is a blown up partial plan view of a portion of the structure of FIG. 1. FIG. 3 is a plan view of a panel taken from FIG. 2. FIG. 4 is a sectional view taken along lines 4--4 of FIG. 2. FIG. 5 is a sectional view taken along lines 5--5 of FIG. 3. FIG. 6 is a sectional view taken along lines 6--6 of FIG. 2. FIG. 7 is a sectionalized plan view of a different embodiment of the panel of FIG. 3. FIG. 8 is a view taken along lines 8--8 of FIG. 7. FIG. 9 is a perspective view of a spacer used in this invention. FIG. 10 is a plan view showing framing for an opening through the structure of this invention. DETAILED DESCRIPTION An elongate hollow composite structure 10 made up of an inner skin 12 and an outer skin 14 each made up of filaments which preferably are wound at ±10° or essentially longitudinally and others wound at ±80° or essentially circumferentially. These fibers may be any of the high strength fibers such as glass, boron, graphite or kelvar with graphite preferred, and may be in the form of individual filaments, a group of filaments or in a tape. The filament are embedded in a plastic or resin such as an epoxy, a polyamide or a polyimide which may be preimpregnated onto the filaments or may be applied to the wound fibers. A cap or reinforcing strip 16 in a spaced apart pattern such as a geodesic pattern crosscross each other and are in contact with the inner skin, and a similar crisscrossing reinforcing strip 18 is in contact with the outer skin. The center of crossing of these reinforcing cap strips are radially aligned with respect to each other. These strips are each made up of spirally wound filaments embedded in a resin with the same types of fibers and resins as are used in the skins. A series of reinforcing plugs 20 are located to extend between the reinforcing strips with the axis of the plugs extending radially between the intersection of the crisscrossing strips. These plugs, as best shown in FIG. 9, are preferably cruciform in shape with center section 22 and with four tapered blades 24. A socket 26 is axially located in the center section and faces radially inward with respect to the composite structure to accept a fastener such as the bolt 28 shown. The blades are positioned to extend in the direction of the reinforcing strips and are slightly indented top and bottom at 30 to accommodate the extra thickness 17 and 19 of the respective inner and outer reinforcing strips where they cross each other. These reinforcing plugs or spaces may be of any light weight high strength material with chopped graphite fibers embedded in an epoxy resin preferred. Extending to and filling the space between the inner and outer skins with adjoining reinforcing strips are a series of core blocks or panels 32 that are positioned at the corners with the reinforcing plugs and abut each other along the sides. These panels are of a light weight material such as honeycomb or closed cell foamed resins and are contoured to fit the space. These panels are best shown in FIGS. 2, 3 and 5 are shaped at the corners 34 to match the contour of the sides 36 of the reinforcing plugs 20, at bottom 38 and top 40 to match the contour of the skins, and have reduced thickness near the bottom edge 42 and top edge 44 to allow for the reinforcing strips 16 and 18. These panels preferably also have resin impregnated filaments in tapes with the filaments crisscrossing on a bias, or in other words at ±45° with the tape 46 wound around the outer edge 48 and with the tape of a width to overlap part way onto the sides at the bottom and top edges 42 and 44 to extend under the reinforcing strips. When the resins in these positioned components are cured it makes up a composite structure having inner 12 and outer 14 skins spaced apart with core members 32 and reinforcing plugs 20 and reinforced with crisscrossing I beam like members made up of the reinforcing plugs at the intersection and the inner 16 and outer 18 reinforcing strips joined by reinforcing members 46. A modified panel 32a is used to permit viewing through the structure. In FIGS. 7 and 8 the panel 32a is in two sections with each section cut out at 50 with shaped edges 52 to fit into a U-shaped portion 54 of a windowframe 56. When the two sections are joined around the windowframe the corners 34a, edges 42a and 44a, and resin impregnated biased tape 46a will be shaped to fit between skins 12 and 14 and reinforcing strips 16 and 18, and having corners located by the reinforcing plugs 20. After the composite structure is formed the skins will be cut out around the inside circumference 58 of the windowframe and the skins removed to expose a window opening 60. The transparent material for the window and the details of mounting the same are not shown. FIG. 10 shows the mounting for a doorframe 62 to provide an opening through the composite structure. The doorframe has a U-shaped outer periphery 64 into which contoured edges 42b and 44b of core panels 32b extend. These edges are shown covered with resin impregnated biased tape 46b. A door 65 has a structural member 66 located adjacent the inside periphery 67 of the doorframe 62. This structural member has a U-shaped inner periphery 68 into which contoured edges of core panels extend. Skins 12 and 14 and reinforcing strips 16 and 18 extend over the doorframe and over the door. Reinforcing plugs 20 are located at the intersection of the reinforcing strips. After the composite is cured the skins and reinforcing strips are cut through around the inside periphery 67 of the doorframe to provide an opening through the structure and to provide a door for the opening. To prepare the composite a mandrel 70 which has an outside contour which is the shape of the inside wall of the finished structure is used. The mandrel has a series of index pins 72 extending outward in a radial direction and located to be the midpoints for the intersection of reinforcing strips 16. A parting agent is placed over the mandrel and skin 12 is formed using resin impregnated fibers that are laid down in a spiral fashion to completely cover the mandrel with a skin of the desired thickness. For many applications this skin will be of graphite fibers impregnated with epoxy resin, and built up to about 0.022" thick. During the layup of the skins the windings, which spirally wind essentially horizontally and others spirally wind essentially circumferentially, settle around the pins so that the pins protrude through the windings. Next the cap strips or reinforcing strips 16 of resin impregnated filaments are spirally wound in a spaced apart pattern with the strips intersecting at and settling around the index pins 72. These strips may extend longitudinally and circumferentially, however, it is preferred they be wound at about 45 degrees and in a geodesic pattern and about 0.055" thick. In the next step the reinforcing spacers or plugs 20 which preferably are cruciform in shape are placed over each of the index pins so that the blades 20 of the spacers extend in the direction of the reinforcing strips 16 and the axis of the plugs extend radially. The index pins extend into the inwardly directed sockets 26 to hold and position the reinforcing plugs. At least some of these sockets are threaded to accept a threaded fastener, however, the index pins insert into the position, but do not thread into the sockets. The formed core panels 32 are then positioned with surface 38 against the skin 12 and the resin impregnated biased tape 46 that surrounds the edge of the panels contacting the sides 36 of contiguous plugs at the corners and abutting each other elsewhere around the periphery. In those positions where windows are desired a windowframe 56 with special panels 32a are used in place of the regular panels 32. In the locations where doors are desired, the doorframe 62 with adjacent panels 32b, and the doors 65 with adjacent panels 32c replace some of the regular panels 32. As the next step resin impregnated filaments are wound in strips 18 to crisscross at the axis of the reinforcing plugs. These strips are oriented the same as the first layer of strips 16. A layer of resin impregnated filaments is then laid in a crisscrossing fashion with fibers spirally wound essentially longitudinally and circumferentially to form an outer skin 14. The mandrel with laid up components is then heated to cure the resins and form a composite structure. The core material expands somewhat at the curing temperature to provide pressure on the skins and reinforcing strips. Once the resins are cured the mandrel with index pins is collapsed, the materials are cut away from both the inside and outside layers at the windowframes to expose the windows and from around the doorframes to permit entry into and out of the composite structure.
An elongate hollow structure with a plurality of reinforcements arranged in a pattern and acting as spacers between a pair of skins. The skins are of resin impregnated wound filaments with reinforcing strips of facing preimpregnated wound filaments that crisscross at the spacing reinforcements, abutting panels extend between adjacent reinforcing spacers to fill the space between the skins, and the structure is bonded with resin into a composite structure.
Briefly describe the main idea outlined in the provided context.
[ "This is a division of application Ser.", "No. 930,457 filed Aug. 2, 1978 now U.S. Pat. No. 4,230,293.", "BACKGROUND OF THE INVENTION Present day airplanes utilize an efficient structure that is lightweight for a given loading.", "Composite materials are recognized as offering a potential for an even more efficient, weight wise, structure.", "In U.S. Pat. No. 2,817,484 to Stenzel it shows a fuselage type structure with spirally wound hollow metal members, and longitudinal members both bonded together with a bonding agent.", "SUMMARY OF THE INVENTION An inner and an outer skin of filaments wound circumferentially and longitudinally each have facing crisscrossing helically wound filaments in reinforcing strips.", "The skins are spaced apart with reinforcing plugs located to contact the strips at the intersections.", "The plugs have inward extending fastener sockets and the inner skin and reinforcing strips have contiguous openings to permit entry into the sockets.", "Panels extend between adjacent plugs and the two skins and all the components are integrally joined with resins into a composite structure.", "Frames for support of openings through the structure are integrally located within the composite.", "DESCRIPTION OF THE DRAWINGS FIG. 1 shows a fragmented perspective view of the composite structure of this invention with parts broken away to show the buildup of the composite.", "FIG. 2 is a blown up partial plan view of a portion of the structure of FIG. 1. FIG. 3 is a plan view of a panel taken from FIG. 2. FIG. 4 is a sectional view taken along lines 4--4 of FIG. 2. FIG. 5 is a sectional view taken along lines 5--5 of FIG. 3. FIG. 6 is a sectional view taken along lines 6--6 of FIG. 2. FIG. 7 is a sectionalized plan view of a different embodiment of the panel of FIG. 3. FIG. 8 is a view taken along lines 8--8 of FIG. 7. FIG. 9 is a perspective view of a spacer used in this invention.", "FIG. 10 is a plan view showing framing for an opening through the structure of this invention.", "DETAILED DESCRIPTION An elongate hollow composite structure 10 made up of an inner skin 12 and an outer skin 14 each made up of filaments which preferably are wound at ±10° or essentially longitudinally and others wound at ±80° or essentially circumferentially.", "These fibers may be any of the high strength fibers such as glass, boron, graphite or kelvar with graphite preferred, and may be in the form of individual filaments, a group of filaments or in a tape.", "The filament are embedded in a plastic or resin such as an epoxy, a polyamide or a polyimide which may be preimpregnated onto the filaments or may be applied to the wound fibers.", "A cap or reinforcing strip 16 in a spaced apart pattern such as a geodesic pattern crosscross each other and are in contact with the inner skin, and a similar crisscrossing reinforcing strip 18 is in contact with the outer skin.", "The center of crossing of these reinforcing cap strips are radially aligned with respect to each other.", "These strips are each made up of spirally wound filaments embedded in a resin with the same types of fibers and resins as are used in the skins.", "A series of reinforcing plugs 20 are located to extend between the reinforcing strips with the axis of the plugs extending radially between the intersection of the crisscrossing strips.", "These plugs, as best shown in FIG. 9, are preferably cruciform in shape with center section 22 and with four tapered blades 24.", "A socket 26 is axially located in the center section and faces radially inward with respect to the composite structure to accept a fastener such as the bolt 28 shown.", "The blades are positioned to extend in the direction of the reinforcing strips and are slightly indented top and bottom at 30 to accommodate the extra thickness 17 and 19 of the respective inner and outer reinforcing strips where they cross each other.", "These reinforcing plugs or spaces may be of any light weight high strength material with chopped graphite fibers embedded in an epoxy resin preferred.", "Extending to and filling the space between the inner and outer skins with adjoining reinforcing strips are a series of core blocks or panels 32 that are positioned at the corners with the reinforcing plugs and abut each other along the sides.", "These panels are of a light weight material such as honeycomb or closed cell foamed resins and are contoured to fit the space.", "These panels are best shown in FIGS. 2, 3 and 5 are shaped at the corners 34 to match the contour of the sides 36 of the reinforcing plugs 20, at bottom 38 and top 40 to match the contour of the skins, and have reduced thickness near the bottom edge 42 and top edge 44 to allow for the reinforcing strips 16 and 18.", "These panels preferably also have resin impregnated filaments in tapes with the filaments crisscrossing on a bias, or in other words at ±45° with the tape 46 wound around the outer edge 48 and with the tape of a width to overlap part way onto the sides at the bottom and top edges 42 and 44 to extend under the reinforcing strips.", "When the resins in these positioned components are cured it makes up a composite structure having inner 12 and outer 14 skins spaced apart with core members 32 and reinforcing plugs 20 and reinforced with crisscrossing I beam like members made up of the reinforcing plugs at the intersection and the inner 16 and outer 18 reinforcing strips joined by reinforcing members 46.", "A modified panel 32a is used to permit viewing through the structure.", "In FIGS. 7 and 8 the panel 32a is in two sections with each section cut out at 50 with shaped edges 52 to fit into a U-shaped portion 54 of a windowframe 56.", "When the two sections are joined around the windowframe the corners 34a, edges 42a and 44a, and resin impregnated biased tape 46a will be shaped to fit between skins 12 and 14 and reinforcing strips 16 and 18, and having corners located by the reinforcing plugs 20.", "After the composite structure is formed the skins will be cut out around the inside circumference 58 of the windowframe and the skins removed to expose a window opening 60.", "The transparent material for the window and the details of mounting the same are not shown.", "FIG. 10 shows the mounting for a doorframe 62 to provide an opening through the composite structure.", "The doorframe has a U-shaped outer periphery 64 into which contoured edges 42b and 44b of core panels 32b extend.", "These edges are shown covered with resin impregnated biased tape 46b.", "A door 65 has a structural member 66 located adjacent the inside periphery 67 of the doorframe 62.", "This structural member has a U-shaped inner periphery 68 into which contoured edges of core panels extend.", "Skins 12 and 14 and reinforcing strips 16 and 18 extend over the doorframe and over the door.", "Reinforcing plugs 20 are located at the intersection of the reinforcing strips.", "After the composite is cured the skins and reinforcing strips are cut through around the inside periphery 67 of the doorframe to provide an opening through the structure and to provide a door for the opening.", "To prepare the composite a mandrel 70 which has an outside contour which is the shape of the inside wall of the finished structure is used.", "The mandrel has a series of index pins 72 extending outward in a radial direction and located to be the midpoints for the intersection of reinforcing strips 16.", "A parting agent is placed over the mandrel and skin 12 is formed using resin impregnated fibers that are laid down in a spiral fashion to completely cover the mandrel with a skin of the desired thickness.", "For many applications this skin will be of graphite fibers impregnated with epoxy resin, and built up to about 0.022"", "thick.", "During the layup of the skins the windings, which spirally wind essentially horizontally and others spirally wind essentially circumferentially, settle around the pins so that the pins protrude through the windings.", "Next the cap strips or reinforcing strips 16 of resin impregnated filaments are spirally wound in a spaced apart pattern with the strips intersecting at and settling around the index pins 72.", "These strips may extend longitudinally and circumferentially, however, it is preferred they be wound at about 45 degrees and in a geodesic pattern and about 0.055"", "thick.", "In the next step the reinforcing spacers or plugs 20 which preferably are cruciform in shape are placed over each of the index pins so that the blades 20 of the spacers extend in the direction of the reinforcing strips 16 and the axis of the plugs extend radially.", "The index pins extend into the inwardly directed sockets 26 to hold and position the reinforcing plugs.", "At least some of these sockets are threaded to accept a threaded fastener, however, the index pins insert into the position, but do not thread into the sockets.", "The formed core panels 32 are then positioned with surface 38 against the skin 12 and the resin impregnated biased tape 46 that surrounds the edge of the panels contacting the sides 36 of contiguous plugs at the corners and abutting each other elsewhere around the periphery.", "In those positions where windows are desired a windowframe 56 with special panels 32a are used in place of the regular panels 32.", "In the locations where doors are desired, the doorframe 62 with adjacent panels 32b, and the doors 65 with adjacent panels 32c replace some of the regular panels 32.", "As the next step resin impregnated filaments are wound in strips 18 to crisscross at the axis of the reinforcing plugs.", "These strips are oriented the same as the first layer of strips 16.", "A layer of resin impregnated filaments is then laid in a crisscrossing fashion with fibers spirally wound essentially longitudinally and circumferentially to form an outer skin 14.", "The mandrel with laid up components is then heated to cure the resins and form a composite structure.", "The core material expands somewhat at the curing temperature to provide pressure on the skins and reinforcing strips.", "Once the resins are cured the mandrel with index pins is collapsed, the materials are cut away from both the inside and outside layers at the windowframes to expose the windows and from around the doorframes to permit entry into and out of the composite structure." ]
This is a Divisional Application of U.S. patent application Ser. No. 11/880,583, filed on Jul. 23, 2007 now U.S. Pat. No. 7,750,421, which is herein incorporated by reference in its entirety and assigned to a common assignee. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a current perpendicular to plane (CPP) magnetic random access memory (CPP-MRAM) cell formed using a magnetic tunneling junction (MTJ) as the basic memory element, wherein a spin torque transfer (STT) effect is used to change the magnetization direction of the MTJ ferromagnetic free layer. 2. Description of the Related Art The conventional magnetic tunneling junction (MTJ) device is a form of ultra-high magnetoresistive device in which the relative orientation of the magnetic moments of parallel, vertically separated, upper and lower magnetized layers controls the flow of spin-polarized electrons tunneling through a very thin dielectric layer (the tunneling barrier layer) formed between those layers. When injected electrons pass through the upper layer they are spin polarized by interaction with the magnetic moment of that layer. The majority of the electrons emerge polarized in the direction of the magnetic moment of the upper layer, the minority being polarized opposite to that direction. The probability of such a polarized electron then tunneling through the intervening tunneling barrier layer into the lower layer then depends on the availability of states within the lower layer that the tunneling electron can occupy. This number, in turn, depends on the magnetization direction of the lower electrode. The tunneling probability is thereby spin dependent and the magnitude of the current (tunneling probability times number of electrons impinging on the barrier layer) depends upon the relative orientation of the magnetizations of magnetic layers above and below the barrier layer. The MTJ device can therefore be viewed as a kind of multi-state resistor, since different relative orientations (e.g. parallel and antiparallel) of the magnetic moments will change the magnitude of a current passing through the device. In a common type of device configuration (spin filter), one of the magnetic layers has its magnetic moment fixed in direction (pinned) by exchange coupling to an antiferromagnetic (AFM) layer, while the other magnetic layer has its magnetic moment free to move (the free layer). The magnetic moment of the free layer is then made to switch its direction from being parallel to that of the pinned layer, whereupon the tunneling current is large, to being antiparallel to the pinned layer, whereupon the tunneling current is small. Thus, the device is effectively a two-state resistor. The switching of the free layer moment direction (writing) is accomplished by external magnetic fields that are the result of currents passing through conducting lines adjacent to the cell. Once the cell has been written upon, the circuitry must be able to detect whether the cell is in its high or low resistance state, which is called the “read” process. This process must both measure the resistance of the written-upon cell and then compare that resistance to that of a reference cell in a fixed resistance state, to determine if the written-upon cell is in its high or low state. Needless to say, this process also introduces some statistical difficulties associated with the variation of resistances of the cells. FIG. 1 is a highly schematic drawing showing an overhead view of a conventional MRAM cell comprising an MTJ cell element ( 1000 ) positioned between (or at the intersection of) vertically separated orthogonal word ( 200 ) and bit ( 100 ) lines. The cell element ( 1000 ) is drawn with a slightly elliptical horizontal cross-section because such an anisotropic shape (“shape anisotropy”) produces a corresponding magnetic anisotropy within the free layer that assists its magnetic moment in retaining a thermally stable fixed position after switching fields have been turned off. The direction along the free layer in which it is energetically favorable for the moment to remain and from which it should be difficult to switch the magnetic moment unintentionally (as with thermal effects), the longer direction in this case, is called the “easy axis” of the layer. The axis perpendicular to the easy axis is called the “hard axis.” The fields produced by currents in each of the two lines are between about 30 to 60 Oersteds in magnitude. According to the diagram, the word line field will be along the easy axis of the cell element, the bit line field will be along the easy axis. The use of magnetic fields externally generated by current carrying lines (as in FIG. 1 ) to switch the magnetic moment directions becomes problematic as the size of the MRAM cells decreases and, along with their decrease, so must the width of the current carrying lines. The smaller width lines require greater currents to produce the necessary switching fields, greatly increasing power consumption. For this reason, a new type of magnetic device, called a spin transfer device, described by Slonczewski, (U.S. Pat. No. 5,695,164) and Covington (U.S. Pat. No. 7,006,375), has been developed, that seems to eliminate some of the problems associated with the excessive power consumption necessitated by external switching fields. The spin transfer device shares some of the operational features of the conventional MTJ cell (particularly the read process) described above, except that the switching of the free layer magnetic moment (the write process) is produced by passage of the spin polarized current itself. In this device, unpolarized conduction electrons passing through a first magnetic layer having its magnetic moment oriented in a given direction (such as the pinned layer) are preferentially polarized by their passage through that layer by a quantum mechanical exchange interaction with the polarized bound electrons in the layer. Such a polarization can occur to conduction electrons that reflect from the surface of the magnetized layer as well as to those that pass through it. The efficiency of such a polarization process depends upon the crystalline structure of the layer. When such a stream of polarized conduction electrons subsequently pass through a second magnetic layer (such as the free layer) whose polarization direction is not fixed in space, the polarized conduction electrons exert a torque on the bound electrons in the magnetic layers which, if sufficient, can reverse the polarization of the bound electrons and, thereby, reverse the magnetic moment of the magnetic layer. The physical explanation of such a torque-induced reversal is complicated and depends upon induction of spin precession and certain magnetic damping effects (Gilbert damping) within the magnetic layer (see Slonczewski, below). If the magnetic moment of the layer is directed along its easy magnetic axis, the required torque is minimized and the moment reversal occurs most easily. The use of a current internal to the cell to cause the magnetic moment reversal requires much smaller currents than those required to produce an external magnetic field from adjacent current carrying lines to produce the moment switching. Much recent experimental data confirm magnetic moment transfer as a source of magnetic excitation and, subsequently, magnetic moment switching. These experiments confirm earlier theoretical predictions (J. C. Slonczewski, J. Magn. Mater. 159 (1996) LI, and J. Z. Sun, Phys. Rev. B., Vol. 62 (2000) 570). These latter papers show that the net torque, Γ, on the magnetization of a free magnetic layer produced by spin-transfer from a spin-polarized DC current is proportional to: Γ= sn m x(n s xn m ),  (1) Where s is the spin-angular momentum deposition rate, n s is a unit vector whose direction is that of the initial spin direction of the current and n m is a unit vector whose direction is that of the free layer magnetization and x symbolizes a vector cross product. According equation (1), the torque is maximum when n s is orthogonal to n m . Referring to FIG. 2 , there is shown a schematic illustration of an exemplary prior art MTJ cell element (such as that in FIG. 1 ) being contacted from above by a bit line ( 100 ) and from below by a bottom electrode ( 300 ). The bottom electrode is in electrical contact, through a conducting via ( 80 ), with a CMOS transistor ( 500 ) that provides current to the MTJ element when the element is selected in a read or write operation. Moving vertically upward from bottom electrode to bit line this prior art storage device consists of an underlayer ( 1 ), which could be a seed layer or buffer layer, an antiferromagnetic pinning layer ( 2 ), a synthetic antiferromagnetic (SyAF) pinned reference layer ( 345 ), consisting of a first ferromagnetic layer ( 3 ), a non-magnetic spacer layer ( 4 ) and a second ferromagnetic layer ( 5 ), a non-conducting tunneling barrier layer ( 6 ), a ferromagnetic free layer ( 7 ) and a non-magnetic capping layer ( 8 ). Arrows, ( 20 ) and ( 30 ), indicate the antiparallel magnetization directions of the two ferromagnetic layers ( 3 ) and ( 5 ) of the SyAF pinned layer ( 345 ). The double-headed arrow ( 40 ) in free layer ( 7 ) indicates that this layer is free to have its magnetic moment directed in either of two directions. Referring again to FIG. 2 it is noted that when a certain critical current (arrow ( 50 ) is directed from bottom to top (layer ( 1 ) to layer ( 8 )), the free layer magnetization ( 40 ) would be switched to be opposite to the direction of the reference layer's magnetization ( 30 ) by the spin-transfer torque. This puts the MTJ cell into its high resistance state. Conversely, if the current is directed from top to bottom ( 60 ), the free layer magnetization ( 40 ) would be switched, by torque transfer of angular momentum, to the same direction as that of the pinned reference layer's direction ( 30 ), since the conduction electrons have passed through that layer before entering the free layer. The MTJ element is then in its low resistance state. Referring again to FIG. 2 , this entire configuration represents a schematic diagram of a single spin-RAM memory cell that utilizes the spin transfer effect (denoted hereinafter as an STT-RAM) for switching an MTJ type element. In this paper, we will use the term “element” to describe the basic MTJ structure comprising a tunneling barrier layer sandwiched between ferromagnetic fixed and free layers. We shall use the term “memory cell” to denote the combination of the MTJ element incorporated within the circuitry shown that permits the element to be written on and read from. Such circuitry includes intersecting current carrying lines that allow a particular element to be accessed and also a CMOS transistor that allows a current to be injected into the element. The word line provides the bit selection (i.e., selects the particular cell which will be switched by means of a current passing through it between the bit line and the source line) and the transistor provides the current necessary for switching the MTJ free layer of the selected cell. Although it is not shown in this simplified figure, the cell is read by applying a bias voltage between the bit line and source line, thereby measuring its resistance and comparing that resistance with a standard cell in the circuit (not shown). The critical current for spin transfer switching, I c , is generally a few milliamperes for an 180 nm sub-micron MTJ cell (of cross-sectional area A approximately A=200 nm×400 nm). The corresponding critical current density, J c , which is I c /A, is on the order of several 10 7 Amperes/cm 2 . This high current density, which is required to induce the spin transfer effect, could destroy the insulating tunneling barrier in the MTJ cell, such as a layer of AlOx, MgO, etc. The difference between an STT-RAM and a conventional MRAM is only in the write operation mechanism; the read operation is the same for both types of cell. In order for the spin transfer magnetization mechanism switching to be viable in the 90 nm MTJ cell structure and smaller, the critical current density must be lower than 10 6 A/cm 2 if it is to be driven by a CMOS transistor that can typically deliver 100μA per 100 nm of gate width. For STT-RAM applications, the ultra-small MTJ cells must exhibit a high tunnel magnetoresistance ratio, TMR=dR/R, much higher than the conventional MRAM-MTJ that uses AlOx as a tunneling barrier layer and has a NiFe free layer. Such MRAM-MTJ cells have a dR/R˜40%. It has recently been demonstrated (S. C. Oh et al., “Excellent scalability and switching characteristics in Spin-transfer torque MRAM” IEDM2006 288.1 and “Magnetic and electrical properties of magnetic tunnel junction with radical oxidized MgO barriers,” IEEE Trans. Magn. P 2642 (2006)) that a highly oriented (001) CoFe(B)/MgO/CoFe(B) MTJ cell is capable of delivering dR/R>200%. Furthermore, in order to have a satisfactory “read margin”, TMR/(R p covariance), where R p is the MTJ resistance for parallel alignment of the free and pinned layers, of at least 15 and preferably >20 is required. It is therefore essential to find a method of fabricating the CoFe(B)/MgO/CoFe(B) MTJ cell with a good read margin for read operation. Note, “R p covariance” indicates the statistical spread of R p values. In MRAM MTJ technology, R p is as defined above and R ap is the MTJ resistance when the free and pinned layers have their magnetizations aligned in an antiparallel configuration. Uniformity of the TMR ratio and the absolute resistance of the cell are critical to the success of MRAM architecture since the absolute value of the MTJ resistance is compared to the resistance of a reference cell during the read operation. If the active device resistances in a block of memory show a high variation in resistance (i.e. high R p covariance, or R ap covariance), a signal error can occur when they are compared with the reference cell. In order to have a good read margin TMR/(R p covariance), should have a minimum value of 12 and most preferably be >20. To apply spin transfer switching to the STT-RAM, we have to decrease I c by more than an order of magnitude. The intrinsic critical current density, J c , is given by Slonczewski (J. C. Slonczewski, J. Magn. Mater. 159 (1996) LI,) as: J c =2 eαM s t F ( H a +H k 2 πM s )/ hη   (1) where e is the electron charge, α is the Gilbert damping constant, t F is the free layer thickness, h is the reduced Planck's constant, η is the spin-transfer efficiency (related to the tunneling spin polarization factor of the incident spin-polarized current), H a is the external applied field, H k is the uniaxial anisotropy field and 2πM s is the demagnetization field of the free layer. Normally the demagnetization field is much larger than the two other magnetic fields, so equation (1) can be rewritten: I c ˜αM s V/hη,  (2) where V is the magnetic volume, V=M s t F A, which is related to the thermal stability function term, K u V/k b T, which governs the stability of the magnetization relative to thermally-induced fluctuations. M. Hosami (“A novel nonvolatile memory with spin torque transfer magnetization switching: Spin RAM” 2005 IEDM, paper 19-1), discusses a Spin-RAM 4 Kbit array which is fabricated using a stack of the following form: CoFeB/RF-sputtered MgO/CoFeB with a MnPt pinning layer. This MTJ stack is processed using 350° C., 10KOe annealing. The cell size is a 100 nm×150 nm oval. Patterning of such sub 100 nm oval MTJ elements is done using e-beam lithography. The tunnel barrier layer is (001) crystallized MgO whose thickness is less than 10 angstroms for the desired RA of about 20 Ω-μm 2 . Intrinsic dR/R of the MTJ is 160%, although under operational conditions (0.1 V bias, for read determination) it is about 100%. Using a current pulse width of 10 ns, the critical current density is about 2.5×10 6 A/cm 2 . The amounts to a critical current of 375 μA. The distribution of write voltages for the array, for the high resistance state to the low resistance state has shown a good write margin. Resistance distributions for the high and low resistance states has a sigma (R p covariance) around 4%. Thus, under operational conditions, (TMR/R p covariance) is 25. This is equivalent to the conventional 4-Mbit CoFeB/AlOx/NiFe MTJ-MRAM in which dR/R (0.3V biased) typically is about 20-25%. For a R p covariance=1%, TMR/(R p covariance) is >20. S. C. Oh et al., cited above, describes an STT-RAM utilizing spin torque transfer where a CoFeB/RF-sputtered MgO/CoFeB was processed with a 360° C.-10KOe annealing. Pinning layer for the stack is MnPt. MgO thickness is controlled to less than 10 angstroms to give an RA of about 50 Ω-μm 2 . MRAM circuits made of sub-100 nm MTJ cells were made using conventional deep UV lithography. For the 80 nm×160 nm MRAM MTJ, J c at 10 ns pulses is about 2.0×10 6 A/cm 2 . TMR at 400 mV bias is about 58% and the read margin, TMR/R p covariance, for 100 nm×200 nm cells is 7.5, corresponding to a R p covariance of 7.8%. J. Hayakawa et al. (“Current-driven magnetization switching in CoFeB/MgO/CoFeB magnetic tunnel junctions, Japn. J. Appl. Phys. V 44, p. 1267 (2005)) has reported critical current densities of 7.8 and 8.8×10 5 and 2.5×10 6 with 10 ns pulse width, for MTJ cells processed with 270, 300 and 350° C. annealing. MgO barrier layer is about 8.5 angstroms thick, yielding a RA of about 10 Ω-μm 2 . Intrinsic MR as a function of the annealing temperature for an MTJ stack formed of Co 40 Fe 40 B 20 /MgO/Co 40 Fe 40 B 20 with a 20 angstrom thick Co 40 Fe 40 B 20 free layer are 49, 73 and 110% respectively. It is noted that the free layer in an MTJ processed at 270 and 300° annealing temperatures is amorphous. The pinning layer for the MTJ stack was IrMn. Y. Huai et al. (“Spin transfer switching current reduction in magnetic tunnel junction based dual spin filter structures” Appl. Phys. Lett. V 87, p 222510 (2005)) have reported on spin-transfer magnetization transfer of a dual spin valve of the following configuration: Ta/MnPt/CoFe/Ru/CoFeB/Al 2 O 3 /CoFeB/Spacer/CoFe/MnPt/Ta It is noted that the free layer of the dual structure is made of a low saturation moment (approx. 1000 emu/cm 3 ) amorphous CoFeB. The nominal MTJ size is 90 nm×140 nm. RA is about 20 Ω-μm 2 and dR/R is about 20%. For a dual spin-filter (DSF) structure, the free layer experiences the spin transfer effect on both faces, so the critical current density has been reduced to approx. 1.0×10 6 A/cm 2 . C. Horng et al. (docket No. HMG06-042. “A novel MTJ to reduce spin-transfer magnetization switching current”) is assigned to the same assignee (Magic Technologies) as the present invention and fully incorporated herein by reference. Horng et al. have produced an STT-MTJ test structure that includes a MTJ stack of the form: Ta/NiCr/eMnPt/Co 75 Fe 25 /Ru7.5/Co 60 Fe 20 B 20 -Co 75 Fe 25 /(NOX)MgO 11/Co 60 Fe 20 B 20 /Ta Which is processed at 265° C.-2 hrs-10KOe annealing, so that the Co 60 Fe 20 B 20 remains amorphous. It is noted that the pinning layer is MnPt. RA of the MTJ is controlled to less than 10 Ω-μm 2 and intrinsic dR/R is about 100%. For the 100 nm×150 nm size MTJ, patterned using conventional photo-lithography of the 180 nm node technology, dR/R at 0.1 V bias is about 70-80%. Due to the fact that no array was constructed, there was no determination of R p covariance. However, the covariance for a conventional MRAM of the same basic MTJ structure, but 200 nm×325 nm was measured to about 3.5%. Extrapolation to the 100 nm×150 nm size of the STT-MTJ predicts that the covariance would be about 7%. This value would not be sufficient to provide a good read margin. The TMR sensor currently under production at Headway Technologies uses an MTJ element of the form: Ta/Ru/IrMn/CoFe/Ru/CoFeB/CoFe/MgO/CoFe-NiFe/NiFeHf In this configuration, the pinning layer is IrMn. TMR sensor size when the resistance measurements are made (i.e., unlapped) is 100 nm×500 nm. Patterning is done using conventional photo-lithography of the 180 nm node technology. R p covariance across the 6″ wafer for that sensor size is about 3%. Scaling to a 100 nm×150 nm size, the covariance is projected to be about 5%. It should be noted that to obtain improvement in R p covariance, the photo-lithography using the 65-90 nm node technology, as is now practiced in semiconductor technology, would be viable. C. Bilzer et al. (“Study of the dynamic magnetic properties of soft CoFeB films”, J. Appl. Phys. V 100, 053903 (2006)) has measured the magnetization damping parameters for the ion-beam deposited Co 72 Fe 18 B 10 film as a function of film thickness and crystalline state. Amorphous Co 72 Fe 18 B 10 showed low damping with a between 0.006 and 0.008, which was thickness independent. Crystalline Co 80 Fe 20 shows a damping factor that is approximately a factor of 2 higher. M. Oogane et al. (“Magnetic damping in ferromagnetic thin film”, Japn. J. Appl. Phys. V 45, p 3889 (2006)) have measured the Gilbert damping factor for the ternary Fe—Co—Ni and CoFeB films. As shown in FIG. 6 , a low damping constant is measured for the Fe rich FeCo and the Fe—Ni binary alloys. For the CoFeB alloys, as shown in FIG. 7 , the damping constant is 0.0038 and 0.010 respectively for amorphous Co 40 Fe 40 B 20 and Co 60 Fe 20 B 20 . The above prior art tends to imply that: 1. J c is greater than 2×10 6 A/cm 2 for the CoFeB/MgO/CoFeB MTJ with a crystalline CoFeB free layer. 2. J c less than 1.0×10 6 A/cm 2 is achievable for the CoFeB/MgO/CoFeB MTJ with an amorphous CoFeB free layer. 3. The R p covariance for an STT-RAM MTJ made, using conventional 180 nm node photo-lithography, with an MnPt (pinning)/CoFe(B)MgO/CoFeB structure is greater than or equal to 7.5%, while a covariance that is less than or equal to 5% may be achievable for the MTJ with an IrMn pinning layer. 4. A low damping factor free layer is critical for reducing the spin-torque magnetization switching current. An examination of the patented prior art shows an increasing number of inventions utilizing the STT approach to MRAM switching. Although this prior art describes many different MTJ stack configurations and layer materials, none of them address the particular combination of conclusions that we have drawn and that are listed above in 1. through 4. Shimazawa et al. (U.S. patent application Ser. No. 2007/0086120), Ashida et al. (U.S. patent application Ser. No. 2007/0076469) and Huai et al. (U.S. patent application Ser. No. 2006/01022969) all teach an AFM layer comprising IrMn. Nguyen et al. (U.S. Pat. No. 6,958,927) and Huai et al. (U.S. Pat. No. 7,126,202) teach that a first AFM layer is preferably IrMn. Huai et al. (U.S. Pat. No. 6,967,863) discloses that an AFM layer is preferably IrMn or PtMn. Huai et al. (U.S. Pat. No. 7,106,624) states that the AFM is preferably PtMn but “nothing prevents” the use of IrMn instead. Covington (U.S. Pat. No. 7,006,375) shows a pinned layer that can be either IrMn or PtMn. Pakala et al. (U.S. patent application Ser. No. 2006/0128038) discloses that seed layers may be used to provide a desired texture to the AFM layer. For example, if IrMn is used as the AFM layer, then a TaN layer should be used. The present invention will describe a spin transfer MRAM device in which a new form of free layer, combined with an IrMn pinning layer will address the issues raised above in statements 1-4. SUMMARY OF THE INVENTION A first object of the present invention is to provide an MTJ element for an STT-MRAM cell wherein the critical current for magnetization switching by spin-torque transfer (STT) is lowered. A second object of this invention is to provide a MTJ element for an STT-RAM configured MRAM device in which the intrinsic (unbiased) and operational (biased) TMR ratio, dR/R, is significantly enhanced and wherein the intrinsic dR/R is between about 125% to 130%. A third object of the present invention is to provide such a device in which the product RA, of MTJ resistance (R) and MTJ element cross-sectional area (A) is less than a certain amount, preferably less than 10 Ω-μm 2 . A fourth object of the present invention is to provide a MTJ element patterned using standard 180 nm photo-lithography and corresponding STT-RAM configured MRAM array of such elements, wherein the statistical distribution of MTJ resistances has a low covariance, preferably less than 5%. A fifth object of the present invention is to provide a MTJ element and corresponding STT-RAM configured MRAM array of such elements, wherein the read margin, (TMR/R p covariance), is greater than 15, and for an element of cross-sectional area 100 nm×150 nm is at least 20. A sixth object of the present invention is to provide such an MTJ element wherein the structure of the pinning/pinned layer provides a low angular dispersion of the pinned layer magnetic moment direction, preferably 1.6× less than that of conventional configurations. These objects will be met by an MTJ element structure in which the free layer damping constant (Gilbert damping constant a) is reduced to less than that associated with only a free layer of amorphous CoFeB, in which the tunnel barrier layer is deposited in a crystalline form by means of being sputtered from an Mg target and then naturally oxidized, in which highly efficient and enhanced spin polarization is obtained by surrounding the free layer by layers of crystalline Fe and in which the antiferromagnetic pinning layer is a layer of MnIr. The preferred structure of the MTJ element is of the form: Buffer layer/Pinning layer//Co 75 Fe 25 23/Ru7.5/Co 60 Fe 20 B 20 15-Co 75 Fe 25 (API)/Mg8-NOX-Mg4/Fee layer/Ta30/Ru Where the general ordering of the layers is as in FIG. 2 . In the preferred embodiment, the free layer is of the form Fe 3/CoFeB 20/Fe 6, with the two interfacial Fe layers being very thin (respectively 3 and 6 angstroms) and crystalline in structure for enhanced spin polarization of the current, while the CoFeB layer sandwiched between them is amorphous in form to obtain a low Gilbert magnetic damping factor. The tunneling barrier layer is a layer of MgO that is rendered crystalline in nature by being formed by a combination of a sputtering deposition of Mg and a natural oxidation process. The sputtering is onto an exposed surface of AP 1 that has been preconditioned by a plasma treatment to render it smooth/flat. This plasma pretreatment is, in turn, highly advantageous, given the fact that the pinning layer for the SyAF pinned layer is a layer of MnIr rather than the more usual MnPt. The MnIr pinning layer, in turn, allows an advantageous annealing process in which the anneal need only be carried out at 265° C. for between 1 and 2 hours in a magnetic field of 10 K Oe. It is to be noted that other prior art processes form the MgO tunneling barrier layer by sputtering directly from an MgO target. This produces an amorphous layer which must be rendered crystalline by use of much higher annealing temperatures than are required in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a prior-art MTJ MRAM device located at the junction of word and bit lines. FIG. 2 is a schematic cross-sectional view of a typical prior art spin-transfer device, including an MTJ element and current providing transistor, that, in the present invention, will utilize a novel combination of a pinning layer a tunneling barrier layer and a free layer. FIG. 3 a , FIG. 3 b and FIG. 3 c are schematic views of the fabrication of the layer structure of a preferred embodiment of the present invention FIG. 4 is a table showing the magnetic performance properties of various MTJ configurations. FIG. 5 a and FIG. 5 b are graphs showing characteristic B-H plots for an MTJ element incorporating an MnPt pinning layer ( FIG. 5 a ) and an MnIr pinning layer ( FIG. 5 b ). FIG. 6 is a graphical illustration of the distribution of Gilbert damping factors for various ternary compositions of Fe—Co—Ni alloy films. FIG. 7 is a graphical illustration of the variation of the Gilbert damping factor for Co—Fe—B films of various compositions. DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the present invention is an STT-RAM memory cell and an array of such cells, in which each cell incorporates an MTJ element that operates in the spin torque transfer (STT) mode. The MTJ element includes an IrMn pinning layer, an SyAP pinned layer, a crystalline barrier layer of naturally oxidized MgO and a crystalline-Fe-sandwiched CoFeB free layer having Gilbert damping constants that are lower than those associated with free layers of only amorphous CoFeB. The preferred MTJ stack configuration is: BE/NiCr50/Ru20/MnIr70/Co 75 Fe 25 23(AP2)/Ru7.5/CoFeB 20 - Co 75 Fe 25 6-7 (AP1)/PT/ Mg8-NOX-Mg4/Fe3-Co 60 Fe 20 B 20 20-Fe6(FL)/Ta Referring to FIG. 3 a , FIGS. 3 b and 3 c , there will be schematically shown the process steps by which the stack configuration is formed. We will retain the essential elements of the numbering of FIG. 2 . Referring first to FIG. 3 a , there is shown the structure labeled BE above, which denotes a bottom conducting line or electrode ( 300 ). Layer ( 1 ) is a layer of NiCr, which is a seed layer. Layer ( 2 ) is the pinning layer, which is a layer of MnIr of 70 angstroms thickness. Layer ( 345 ) is the configuration Co 75 Fe 25 23(AP2)/Ru7.5/CoFeB 20 -Co 75 Fe 25 6-7 (AP 1 ) is a synthetic antiferromagnetic (SyAF) pinned layer, where AP 1 ( 5 ) and AP 2 ( 3 ) denote the two ferromagnetic layers magnetized in antiparallel directions and exchange coupled by the layer of Ru ( 4 ). As we shall explain below, PT denotes a plasma treatment ( 55 ) that is applied to the upper surface of AP 1 and is required to produce the desired objects of the invention. Referring next to FIG. 3 b , there is shown the formation of an MgO (or, similarly, an AlOx) barrier layer ( 6 ) on the plasma treated surface ( 555 ) of AP1. The plasma treatment, which smoothes and renders flat the ( 555 ) surface, is required because layers formed on a MnIr/SyAF combination such as in the present invention are typically rougher than when formed on an MnPt/SyAF combination. Consequently, dR/R and H e (H in ) pf the MnIr MTJ are not as good as that for the MnPt MTJ. To yield high dR/R and low H in , the CoFe(B)/MgO/CoFeB interfaces must be smooth. This is particularly true for the MTJ configuration where the very high dR/R is a result of coherent spin-dependent tunneling through the (001)CoFe(B)/(001)MgO/(001)CoFe(B) MTJ junctions. To prepare a smooth/flat bottom electrode (the bottom electrode denoting the entire portion of the element below the MgO tunneling barrier layer) prior to the MgO deposition, the plasma treatment (PT) process ( 55 ) has been applied to the exposed surface of AP 1 . PT is a low power (20W) Ar ion-milling process that smoothes and flattens the AP 1 surface. The ion energy is sufficiently low so that it does not damage the surface. Referring again to FIG. 3 b , the MgO barrier layer ( 6 ) is made by a process indicated above by Mg8-NOX-Mg4 and which is more fully described by Horng et al cited above. Unlike prior art processes, in which a target of MgO is sputtered and thereby produces an amorphous MgO layer, in the present process an Mg target is sputtered to produce a crystalline Mg layer and that already crystalline layer is then naturally oxidized after deposition to directly produce a crystalline MgO layer. A subsequent second Mg sputtering process completes the layer formation as described by Horng. In its as-deposited state, the naturally oxidized Mg already has a highly oriented (001) crystalline plane texture. In this respect, prior art rf-sputtered (extra-thin) MgO is deposited in an amorphous state and has to rely on subsequent high temperature (>350° C.) annealing processing to obtain a highly oriented (001) structure. Such high temperature annealing is not required in the present invention. Referring now to FIG. 3 c , there is shown the formation of the free layer of the present invention. The free layer ( 7 ) of the configuration above is a composite layer made of an atomic layer thickness (approximately 3 angstroms) crystalline Fe interface layer ( 71 ) and thicker, amorphous layer ( 72 ) of Co 60 Fe 20 B 20 (approximately 20 angstroms) formed upon it. More preferably, as is shown in the figure, an additional crystalline layer ( 73 ) of Fe approximately 6 angstroms in thickness can be inserted between the Co 60 Fe 20 B 20 and the Ta 30 capping layer ( 8 ). These two layers of Fe provide advantageous enhanced electron polarization properties at the interfaces between the MgO layer ( 6 ) and the free layer ( 7 ), between the AP 1 layer ( 5 ) and the MgO layer ( 6 ) and between the free layer ( 7 ) and the Ta layer ( 8 ). Finally, it is also noted from the evidence of FIG. 7 that a crystalline structure free layer of the form Fe(rich)—Co/Fe(rich)—Ni, which is a bilayer of two binary alloys that are rich in Fe, such as FeCo/FeNi can produce an even lower damping factor than the Fe/CoFeB/Fe free layer with amorphous CoFeB shown in the present FIG. 3 c and, in addition, when subjected to a >300° C. (e.g. 350° C.) post annealing can yield a dR/R=200% and a corresponding read margin that is >25. Such a free layer will, therefore, produce another preferred embodiment of the present invention. For comparison, we also made an STT-MTJ element in the configuration of Horng et al., in which the pinning layer is MnPt and the free layer is only amorphous Co 60 Fe 20 B 20 , without the interfacial layers of Fe. To obtain the amorphous Co 60 Fe 20 B 20 layer the MTJ stack is processed using an (250-265° C.)-10KOe (1-2 hour) annealing treatment. Magnetic properties of the stack configurations are displayed in the table of FIG. 4 . It has already been noted here and will be discussed below, that forming the Co 60 Fe 20 B 20 on the atomic layer of Fe produces a higher degree of electron spin polarization than the amorphous layer alone. Referring again to FIG. 4 there is seen a table setting forth the magnetic properties of 7 MTJ stack configurations having the general form: Buffer layer/Pinning layer//Co 75 Fe 25 23/Ru7.5/Co 60 Fe 20 B 20 15-Co 75 Fe 25 (AP1)/ Mg8-NOX-Mg4/Fee layer/Ta30/Ru Row 1 shows the properties of the reference MTJ stack in which the pinning layer is MnPt and the free layer lacks the Fe crystalline layer and consists only of the amorphous CoFeB layer. Row 3 shows a similar structure except that the pinning layer is MnIr and the free layer includes the crystalline Fe layer. MR for row 1 is 103%, while for row 3 it is 118%. This improvement is attributed to the (001) Fe crystalline interface layer in the free layer structure. Due to a rougher bottom electrode, H e (H in ) for the MnIr-MTJ is 7.60 Oe, a twofold increase over the value of 3.73 Oe for the MnPt MTJ of the reference structure. Row 2 and Row 4 , which include a 120 sec. plasma treatment (PT) of the AP 1 surface, show that H e of both the MnPt and MnIr TMJ have been reduced to 2.48 and 4.41 Oe respectively. Having smooth/flat interfaces at the AP1/MgO/free layer enhances the MR for both the MnPt and MnIr structures. For 100 nm×150 nm MTJ elements, MR (at 0.1 V bias read operation) for the MnIr MTJ would be about 100%. To meet the read margin requirement of TMR/(R p covariance) >20, the covariance would have to be less than or equal to 5%. To obtain an amorphous CoFeB layer for its low magnetization damping and low M s , the deposited MTJ stack is annealed using a 265° C. (1-2 hrs) 10K Oe process. Previously, in GMR sensor head fabrication, to obtain a robust MnPt/SyAF pinned layer, post deposition annealing to the MTJ stack was done in a 280° C. (5 hrs)-10 K Oe process. Post deposition annealing for the MnIr/SyAF MTJ, however, is at 250°-265° C. (5 hrs)-10 K Oe. It appears that the 265° C. (1-2 hrs)10K Oe process is more suitable for the MnIr pinning layer structure than for the MnPt pinning structure. In terms of TMR magnetic performance, the MnIr MTJ element is preferred. Referring now to FIGS. 5 a and 5 b , there is shown the B-H characteristic plots for the MTJ element made (in 5 a ) for the MnPt pinning layer and ( 5 b ) for the MnIr pinning layer. The open loop portion of each curve (arrows) allows us to deduce the pinned layer dispersion and the strength of the pinning field for the MnIr MTJ and for the MnPt MTJ. Thus the ratio of H pin (MnIr)/H pin (MnPt) is approximately 1.6. The ratio of dispersion (MnPt)/dispersion (MnIr) is about 1.6. From this, we can also deduce that the covariance ratio of [R p cov. (MnPt)/R p cov (MnIr)] is about 1.6. Using [R p cov. (MnPt)]=7.5% given by Horng et al, we can deduce that [R p cov. (MnIr)]=4.7%, which is in close agreement to Headway Technology's measured MnIr stack covariance for their TMR sensor made with a MnIr pinning layer (described above). Referring to FIG. 6 , it is noted that the boron (B) doping to the CoFe free layer has enhanced the magnetization damping. Use of the Fe crystalline interface layers provides high spin polarization (higher than from the amorphous CoFeB layer alone). As can be seen in FIG. 7 , the damping constant of Fe is α=0.0019 and the damping constant of Co 60 Fe 20 B 20 is α=0.01. The effective damping constant for the composite free layer of Fe/Co 60 Fe 20 B 20 /Fe (with the thicknesses of the two Fe layers being approximately 3 and 6 angstroms respectively and the thickness of the Co 60 Fe 20 B 20 being approximately 20 ang.) is calculated to be α=0.006, which will produce the required improvement of the critical current for magnetic moment switching. It is further noted that an even smaller damping constant can be obtained using a free layer of Fe/Co 40 Fe 40 B 20 /Fe (same Fe thicknesses, but the sandwiched layer of CoFeB being approximately 15 angstroms) since the damping constant of Co 40 Fe 40 B 20 is α=0.0038, which is smaller than the α=0.01 of the Co 60 Fe 20 B 20 . As is finally understood by a person skilled in the art, the preferred embodiments of the present invention are illustrative of the present invention rather than limiting of the present invention. Revisions and modifications may be made to methods, materials, structures and dimensions employed in forming and providing a CPP STT-MTJ MRAM cell, said cell using transfer of spin angular momentum, while still forming and providing such a cell and its method of formation in accord with the spirit and scope of the present invention as defined by the appended claims.
A STT-MTJ MRAM cell that utilizes transfer of spin angular momentum as a mechanism for changing the magnetic moment direction of a free layer includes an IrMn pinning layer, a SyAP pinned layer, a naturally oxidized, crystalline MgO tunneling barrier layer that is formed on an Ar-ion plasma smoothed surface of the pinned layer and a free layer that comprises an amorphous layer of Co 60 Fe 20 B 20 of approximately 20 angstroms thickness or an amorphous ferromagnetic layer of Co 40 Fe 40 B 20 of approximately 15 angstroms thickness formed between two crystalline layers of Fe of 3 and 6 angstroms thickness respectively. The free layer is characterized by a low Gilbert damping factor and by very strong polarizing action on conduction electrons. The resulting cell has a low critical current, a high dR/R and a plurality of such cells will exhibit a low variation of both resistance and pinned layer magnetization angular dispersion.
Identify and summarize the most critical technical features from the given patent document.
[ "This is a Divisional Application of U.S. patent application Ser.", "No. 11/880,583, filed on Jul. 23, 2007 now U.S. Pat. No. 7,750,421, which is herein incorporated by reference in its entirety and assigned to a common assignee.", "BACKGROUND OF THE INVENTION 1.", "Field of the Invention This invention relates generally to a current perpendicular to plane (CPP) magnetic random access memory (CPP-MRAM) cell formed using a magnetic tunneling junction (MTJ) as the basic memory element, wherein a spin torque transfer (STT) effect is used to change the magnetization direction of the MTJ ferromagnetic free layer.", "Description of the Related Art The conventional magnetic tunneling junction (MTJ) device is a form of ultra-high magnetoresistive device in which the relative orientation of the magnetic moments of parallel, vertically separated, upper and lower magnetized layers controls the flow of spin-polarized electrons tunneling through a very thin dielectric layer (the tunneling barrier layer) formed between those layers.", "When injected electrons pass through the upper layer they are spin polarized by interaction with the magnetic moment of that layer.", "The majority of the electrons emerge polarized in the direction of the magnetic moment of the upper layer, the minority being polarized opposite to that direction.", "The probability of such a polarized electron then tunneling through the intervening tunneling barrier layer into the lower layer then depends on the availability of states within the lower layer that the tunneling electron can occupy.", "This number, in turn, depends on the magnetization direction of the lower electrode.", "The tunneling probability is thereby spin dependent and the magnitude of the current (tunneling probability times number of electrons impinging on the barrier layer) depends upon the relative orientation of the magnetizations of magnetic layers above and below the barrier layer.", "The MTJ device can therefore be viewed as a kind of multi-state resistor, since different relative orientations (e.g. parallel and antiparallel) of the magnetic moments will change the magnitude of a current passing through the device.", "In a common type of device configuration (spin filter), one of the magnetic layers has its magnetic moment fixed in direction (pinned) by exchange coupling to an antiferromagnetic (AFM) layer, while the other magnetic layer has its magnetic moment free to move (the free layer).", "The magnetic moment of the free layer is then made to switch its direction from being parallel to that of the pinned layer, whereupon the tunneling current is large, to being antiparallel to the pinned layer, whereupon the tunneling current is small.", "Thus, the device is effectively a two-state resistor.", "The switching of the free layer moment direction (writing) is accomplished by external magnetic fields that are the result of currents passing through conducting lines adjacent to the cell.", "Once the cell has been written upon, the circuitry must be able to detect whether the cell is in its high or low resistance state, which is called the “read”", "process.", "This process must both measure the resistance of the written-upon cell and then compare that resistance to that of a reference cell in a fixed resistance state, to determine if the written-upon cell is in its high or low state.", "Needless to say, this process also introduces some statistical difficulties associated with the variation of resistances of the cells.", "FIG. 1 is a highly schematic drawing showing an overhead view of a conventional MRAM cell comprising an MTJ cell element ( 1000 ) positioned between (or at the intersection of) vertically separated orthogonal word ( 200 ) and bit ( 100 ) lines.", "The cell element ( 1000 ) is drawn with a slightly elliptical horizontal cross-section because such an anisotropic shape (“shape anisotropy”) produces a corresponding magnetic anisotropy within the free layer that assists its magnetic moment in retaining a thermally stable fixed position after switching fields have been turned off.", "The direction along the free layer in which it is energetically favorable for the moment to remain and from which it should be difficult to switch the magnetic moment unintentionally (as with thermal effects), the longer direction in this case, is called the “easy axis”", "of the layer.", "The axis perpendicular to the easy axis is called the “hard axis.”", "The fields produced by currents in each of the two lines are between about 30 to 60 Oersteds in magnitude.", "According to the diagram, the word line field will be along the easy axis of the cell element, the bit line field will be along the easy axis.", "The use of magnetic fields externally generated by current carrying lines (as in FIG. 1 ) to switch the magnetic moment directions becomes problematic as the size of the MRAM cells decreases and, along with their decrease, so must the width of the current carrying lines.", "The smaller width lines require greater currents to produce the necessary switching fields, greatly increasing power consumption.", "For this reason, a new type of magnetic device, called a spin transfer device, described by Slonczewski, (U.S. Pat. No. 5,695,164) and Covington (U.S. Pat. No. 7,006,375), has been developed, that seems to eliminate some of the problems associated with the excessive power consumption necessitated by external switching fields.", "The spin transfer device shares some of the operational features of the conventional MTJ cell (particularly the read process) described above, except that the switching of the free layer magnetic moment (the write process) is produced by passage of the spin polarized current itself.", "In this device, unpolarized conduction electrons passing through a first magnetic layer having its magnetic moment oriented in a given direction (such as the pinned layer) are preferentially polarized by their passage through that layer by a quantum mechanical exchange interaction with the polarized bound electrons in the layer.", "Such a polarization can occur to conduction electrons that reflect from the surface of the magnetized layer as well as to those that pass through it.", "The efficiency of such a polarization process depends upon the crystalline structure of the layer.", "When such a stream of polarized conduction electrons subsequently pass through a second magnetic layer (such as the free layer) whose polarization direction is not fixed in space, the polarized conduction electrons exert a torque on the bound electrons in the magnetic layers which, if sufficient, can reverse the polarization of the bound electrons and, thereby, reverse the magnetic moment of the magnetic layer.", "The physical explanation of such a torque-induced reversal is complicated and depends upon induction of spin precession and certain magnetic damping effects (Gilbert damping) within the magnetic layer (see Slonczewski, below).", "If the magnetic moment of the layer is directed along its easy magnetic axis, the required torque is minimized and the moment reversal occurs most easily.", "The use of a current internal to the cell to cause the magnetic moment reversal requires much smaller currents than those required to produce an external magnetic field from adjacent current carrying lines to produce the moment switching.", "Much recent experimental data confirm magnetic moment transfer as a source of magnetic excitation and, subsequently, magnetic moment switching.", "These experiments confirm earlier theoretical predictions (J.", "C. Slonczewski, J. Magn.", "Mater.", "159 (1996) LI, and J. Z. Sun, Phys.", "Rev. B., Vol. 62 (2000) 570).", "These latter papers show that the net torque, Γ, on the magnetization of a free magnetic layer produced by spin-transfer from a spin-polarized DC current is proportional to: Γ= sn m x(n s xn m ), (1) Where s is the spin-angular momentum deposition rate, n s is a unit vector whose direction is that of the initial spin direction of the current and n m is a unit vector whose direction is that of the free layer magnetization and x symbolizes a vector cross product.", "According equation (1), the torque is maximum when n s is orthogonal to n m .", "Referring to FIG. 2 , there is shown a schematic illustration of an exemplary prior art MTJ cell element (such as that in FIG. 1 ) being contacted from above by a bit line ( 100 ) and from below by a bottom electrode ( 300 ).", "The bottom electrode is in electrical contact, through a conducting via ( 80 ), with a CMOS transistor ( 500 ) that provides current to the MTJ element when the element is selected in a read or write operation.", "Moving vertically upward from bottom electrode to bit line this prior art storage device consists of an underlayer ( 1 ), which could be a seed layer or buffer layer, an antiferromagnetic pinning layer ( 2 ), a synthetic antiferromagnetic (SyAF) pinned reference layer ( 345 ), consisting of a first ferromagnetic layer ( 3 ), a non-magnetic spacer layer ( 4 ) and a second ferromagnetic layer ( 5 ), a non-conducting tunneling barrier layer ( 6 ), a ferromagnetic free layer ( 7 ) and a non-magnetic capping layer ( 8 ).", "Arrows, ( 20 ) and ( 30 ), indicate the antiparallel magnetization directions of the two ferromagnetic layers ( 3 ) and ( 5 ) of the SyAF pinned layer ( 345 ).", "The double-headed arrow ( 40 ) in free layer ( 7 ) indicates that this layer is free to have its magnetic moment directed in either of two directions.", "Referring again to FIG. 2 it is noted that when a certain critical current (arrow ( 50 ) is directed from bottom to top (layer ( 1 ) to layer ( 8 )), the free layer magnetization ( 40 ) would be switched to be opposite to the direction of the reference layer's magnetization ( 30 ) by the spin-transfer torque.", "This puts the MTJ cell into its high resistance state.", "Conversely, if the current is directed from top to bottom ( 60 ), the free layer magnetization ( 40 ) would be switched, by torque transfer of angular momentum, to the same direction as that of the pinned reference layer's direction ( 30 ), since the conduction electrons have passed through that layer before entering the free layer.", "The MTJ element is then in its low resistance state.", "Referring again to FIG. 2 , this entire configuration represents a schematic diagram of a single spin-RAM memory cell that utilizes the spin transfer effect (denoted hereinafter as an STT-RAM) for switching an MTJ type element.", "In this paper, we will use the term “element”", "to describe the basic MTJ structure comprising a tunneling barrier layer sandwiched between ferromagnetic fixed and free layers.", "We shall use the term “memory cell”", "to denote the combination of the MTJ element incorporated within the circuitry shown that permits the element to be written on and read from.", "Such circuitry includes intersecting current carrying lines that allow a particular element to be accessed and also a CMOS transistor that allows a current to be injected into the element.", "The word line provides the bit selection (i.e., selects the particular cell which will be switched by means of a current passing through it between the bit line and the source line) and the transistor provides the current necessary for switching the MTJ free layer of the selected cell.", "Although it is not shown in this simplified figure, the cell is read by applying a bias voltage between the bit line and source line, thereby measuring its resistance and comparing that resistance with a standard cell in the circuit (not shown).", "The critical current for spin transfer switching, I c , is generally a few milliamperes for an 180 nm sub-micron MTJ cell (of cross-sectional area A approximately A=200 nm×400 nm).", "The corresponding critical current density, J c , which is I c /A, is on the order of several 10 7 Amperes/cm 2 .", "This high current density, which is required to induce the spin transfer effect, could destroy the insulating tunneling barrier in the MTJ cell, such as a layer of AlOx, MgO, etc.", "The difference between an STT-RAM and a conventional MRAM is only in the write operation mechanism;", "the read operation is the same for both types of cell.", "In order for the spin transfer magnetization mechanism switching to be viable in the 90 nm MTJ cell structure and smaller, the critical current density must be lower than 10 6 A/cm 2 if it is to be driven by a CMOS transistor that can typically deliver 100μA per 100 nm of gate width.", "For STT-RAM applications, the ultra-small MTJ cells must exhibit a high tunnel magnetoresistance ratio, TMR=dR/R, much higher than the conventional MRAM-MTJ that uses AlOx as a tunneling barrier layer and has a NiFe free layer.", "Such MRAM-MTJ cells have a dR/R˜40%.", "It has recently been demonstrated (S.", "C. Oh et al.", ", “Excellent scalability and switching characteristics in Spin-transfer torque MRAM”", "IEDM2006 288.1 and “Magnetic and electrical properties of magnetic tunnel junction with radical oxidized MgO barriers,” IEEE Trans.", "Magn.", "P 2642 (2006)) that a highly oriented (001) CoFe(B)/MgO/CoFe(B) MTJ cell is capable of delivering dR/R>200%.", "Furthermore, in order to have a satisfactory “read margin”, TMR/(R p covariance), where R p is the MTJ resistance for parallel alignment of the free and pinned layers, of at least 15 and preferably >20 is required.", "It is therefore essential to find a method of fabricating the CoFe(B)/MgO/CoFe(B) MTJ cell with a good read margin for read operation.", "Note, “R p covariance”", "indicates the statistical spread of R p values.", "In MRAM MTJ technology, R p is as defined above and R ap is the MTJ resistance when the free and pinned layers have their magnetizations aligned in an antiparallel configuration.", "Uniformity of the TMR ratio and the absolute resistance of the cell are critical to the success of MRAM architecture since the absolute value of the MTJ resistance is compared to the resistance of a reference cell during the read operation.", "If the active device resistances in a block of memory show a high variation in resistance (i.e. high R p covariance, or R ap covariance), a signal error can occur when they are compared with the reference cell.", "In order to have a good read margin TMR/(R p covariance), should have a minimum value of 12 and most preferably be >20.", "To apply spin transfer switching to the STT-RAM, we have to decrease I c by more than an order of magnitude.", "The intrinsic critical current density, J c , is given by Slonczewski (J.", "C. Slonczewski, J. Magn.", "Mater.", "159 (1996) LI,) as: J c =2 eαM s t F ( H a +H k 2 πM s )/ hη (1) where e is the electron charge, α is the Gilbert damping constant, t F is the free layer thickness, h is the reduced Planck's constant, η is the spin-transfer efficiency (related to the tunneling spin polarization factor of the incident spin-polarized current), H a is the external applied field, H k is the uniaxial anisotropy field and 2πM s is the demagnetization field of the free layer.", "Normally the demagnetization field is much larger than the two other magnetic fields, so equation (1) can be rewritten: I c ˜αM s V/hη, (2) where V is the magnetic volume, V=M s t F A, which is related to the thermal stability function term, K u V/k b T, which governs the stability of the magnetization relative to thermally-induced fluctuations.", "M. Hosami (“A novel nonvolatile memory with spin torque transfer magnetization switching: Spin RAM”", "2005 IEDM, paper 19-1), discusses a Spin-RAM 4 Kbit array which is fabricated using a stack of the following form: CoFeB/RF-sputtered MgO/CoFeB with a MnPt pinning layer.", "This MTJ stack is processed using 350° C., 10KOe annealing.", "The cell size is a 100 nm×150 nm oval.", "Patterning of such sub 100 nm oval MTJ elements is done using e-beam lithography.", "The tunnel barrier layer is (001) crystallized MgO whose thickness is less than 10 angstroms for the desired RA of about 20 Ω-μm 2 .", "Intrinsic dR/R of the MTJ is 160%, although under operational conditions (0.1 V bias, for read determination) it is about 100%.", "Using a current pulse width of 10 ns, the critical current density is about 2.5×10 6 A/cm 2 .", "The amounts to a critical current of 375 μA.", "The distribution of write voltages for the array, for the high resistance state to the low resistance state has shown a good write margin.", "Resistance distributions for the high and low resistance states has a sigma (R p covariance) around 4%.", "Thus, under operational conditions, (TMR/R p covariance) is 25.", "This is equivalent to the conventional 4-Mbit CoFeB/AlOx/NiFe MTJ-MRAM in which dR/R (0.3V biased) typically is about 20-25%.", "For a R p covariance=1%, TMR/(R p covariance) is >20.", "S. C. Oh et al.", ", cited above, describes an STT-RAM utilizing spin torque transfer where a CoFeB/RF-sputtered MgO/CoFeB was processed with a 360° C.-10KOe annealing.", "Pinning layer for the stack is MnPt.", "MgO thickness is controlled to less than 10 angstroms to give an RA of about 50 Ω-μm 2 .", "MRAM circuits made of sub-100 nm MTJ cells were made using conventional deep UV lithography.", "For the 80 nm×160 nm MRAM MTJ, J c at 10 ns pulses is about 2.0×10 6 A/cm 2 .", "TMR at 400 mV bias is about 58% and the read margin, TMR/R p covariance, for 100 nm×200 nm cells is 7.5, corresponding to a R p covariance of 7.8%.", "J. Hayakawa et al.", "(“Current-driven magnetization switching in CoFeB/MgO/CoFeB magnetic tunnel junctions, Japn. J. Appl. Phys. V 44, p. 1267 (2005)) has reported critical current densities of 7.8 and 8.8×10 5 and 2.5×10 6 with 10 ns pulse width, for MTJ cells processed with 270, 300 and 350° C. annealing. MgO barrier layer is about 8.5 angstroms thick, yielding a RA of about 10 Ω-μm 2 . Intrinsic MR as a function of the annealing temperature for an MTJ stack formed of Co 40 Fe 40 B 20 /MgO/Co 40 Fe 40 B 20 with a 20 angstrom thick Co 40 Fe 40 B 20 free layer are 49, 73 and 110% respectively. It is noted that the free layer in an MTJ processed at 270 and 300° annealing temperatures is amorphous. The pinning layer for the MTJ stack was IrMn. Y. Huai et al. (“Spin transfer switching current reduction in magnetic tunnel junction based dual spin filter structures”", "Appl.", "Phys.", "Lett.", "V 87, p 222510 (2005)) have reported on spin-transfer magnetization transfer of a dual spin valve of the following configuration: Ta/MnPt/CoFe/Ru/CoFeB/Al 2 O 3 /CoFeB/Spacer/CoFe/MnPt/Ta It is noted that the free layer of the dual structure is made of a low saturation moment (approx.", "1000 emu/cm 3 ) amorphous CoFeB.", "The nominal MTJ size is 90 nm×140 nm.", "RA is about 20 Ω-μm 2 and dR/R is about 20%.", "For a dual spin-filter (DSF) structure, the free layer experiences the spin transfer effect on both faces, so the critical current density has been reduced to approx.", "1.0×10 6 A/cm 2 .", "C. Horng et al.", "(docket No. HMG06-042.", "“A novel MTJ to reduce spin-transfer magnetization switching current”) is assigned to the same assignee (Magic Technologies) as the present invention and fully incorporated herein by reference.", "Horng et al.", "have produced an STT-MTJ test structure that includes a MTJ stack of the form: Ta/NiCr/eMnPt/Co 75 Fe 25 /Ru7.5/Co 60 Fe 20 B 20 -Co 75 Fe 25 /(NOX)MgO 11/Co 60 Fe 20 B 20 /Ta Which is processed at 265° C.-2 hrs-10KOe annealing, so that the Co 60 Fe 20 B 20 remains amorphous.", "It is noted that the pinning layer is MnPt.", "RA of the MTJ is controlled to less than 10 Ω-μm 2 and intrinsic dR/R is about 100%.", "For the 100 nm×150 nm size MTJ, patterned using conventional photo-lithography of the 180 nm node technology, dR/R at 0.1 V bias is about 70-80%.", "Due to the fact that no array was constructed, there was no determination of R p covariance.", "However, the covariance for a conventional MRAM of the same basic MTJ structure, but 200 nm×325 nm was measured to about 3.5%.", "Extrapolation to the 100 nm×150 nm size of the STT-MTJ predicts that the covariance would be about 7%.", "This value would not be sufficient to provide a good read margin.", "The TMR sensor currently under production at Headway Technologies uses an MTJ element of the form: Ta/Ru/IrMn/CoFe/Ru/CoFeB/CoFe/MgO/CoFe-NiFe/NiFeHf In this configuration, the pinning layer is IrMn.", "TMR sensor size when the resistance measurements are made (i.e., unlapped) is 100 nm×500 nm.", "Patterning is done using conventional photo-lithography of the 180 nm node technology.", "R p covariance across the 6″ wafer for that sensor size is about 3%.", "Scaling to a 100 nm×150 nm size, the covariance is projected to be about 5%.", "It should be noted that to obtain improvement in R p covariance, the photo-lithography using the 65-90 nm node technology, as is now practiced in semiconductor technology, would be viable.", "C. Bilzer et al.", "(“Study of the dynamic magnetic properties of soft CoFeB films”, J. Appl.", "Phys.", "V 100, 053903 (2006)) has measured the magnetization damping parameters for the ion-beam deposited Co 72 Fe 18 B 10 film as a function of film thickness and crystalline state.", "Amorphous Co 72 Fe 18 B 10 showed low damping with a between 0.006 and 0.008, which was thickness independent.", "Crystalline Co 80 Fe 20 shows a damping factor that is approximately a factor of 2 higher.", "M. Oogane et al.", "(“Magnetic damping in ferromagnetic thin film”, Japn.", "J. Appl.", "Phys.", "V 45, p 3889 (2006)) have measured the Gilbert damping factor for the ternary Fe—Co—Ni and CoFeB films.", "As shown in FIG. 6 , a low damping constant is measured for the Fe rich FeCo and the Fe—Ni binary alloys.", "For the CoFeB alloys, as shown in FIG. 7 , the damping constant is 0.0038 and 0.010 respectively for amorphous Co 40 Fe 40 B 20 and Co 60 Fe 20 B 20 .", "The above prior art tends to imply that: 1.", "J c is greater than 2×10 6 A/cm 2 for the CoFeB/MgO/CoFeB MTJ with a crystalline CoFeB free layer.", "J c less than 1.0×10 6 A/cm 2 is achievable for the CoFeB/MgO/CoFeB MTJ with an amorphous CoFeB free layer.", "The R p covariance for an STT-RAM MTJ made, using conventional 180 nm node photo-lithography, with an MnPt (pinning)/CoFe(B)MgO/CoFeB structure is greater than or equal to 7.5%, while a covariance that is less than or equal to 5% may be achievable for the MTJ with an IrMn pinning layer.", "A low damping factor free layer is critical for reducing the spin-torque magnetization switching current.", "An examination of the patented prior art shows an increasing number of inventions utilizing the STT approach to MRAM switching.", "Although this prior art describes many different MTJ stack configurations and layer materials, none of them address the particular combination of conclusions that we have drawn and that are listed above in 1.", "through 4.", "Shimazawa et al.", "(U.S. patent application Ser.", "No. 2007/0086120), Ashida et al.", "(U.S. patent application Ser.", "No. 2007/0076469) and Huai et al.", "(U.S. patent application Ser.", "No. 2006/01022969) all teach an AFM layer comprising IrMn.", "Nguyen et al.", "(U.S. Pat. No. 6,958,927) and Huai et al.", "(U.S. Pat. No. 7,126,202) teach that a first AFM layer is preferably IrMn.", "Huai et al.", "(U.S. Pat. No. 6,967,863) discloses that an AFM layer is preferably IrMn or PtMn.", "Huai et al.", "(U.S. Pat. No. 7,106,624) states that the AFM is preferably PtMn but “nothing prevents”", "the use of IrMn instead.", "Covington (U.S. Pat. No. 7,006,375) shows a pinned layer that can be either IrMn or PtMn.", "Pakala et al.", "(U.S. patent application Ser.", "No. 2006/0128038) discloses that seed layers may be used to provide a desired texture to the AFM layer.", "For example, if IrMn is used as the AFM layer, then a TaN layer should be used.", "The present invention will describe a spin transfer MRAM device in which a new form of free layer, combined with an IrMn pinning layer will address the issues raised above in statements 1-4.", "SUMMARY OF THE INVENTION A first object of the present invention is to provide an MTJ element for an STT-MRAM cell wherein the critical current for magnetization switching by spin-torque transfer (STT) is lowered.", "A second object of this invention is to provide a MTJ element for an STT-RAM configured MRAM device in which the intrinsic (unbiased) and operational (biased) TMR ratio, dR/R, is significantly enhanced and wherein the intrinsic dR/R is between about 125% to 130%.", "A third object of the present invention is to provide such a device in which the product RA, of MTJ resistance (R) and MTJ element cross-sectional area (A) is less than a certain amount, preferably less than 10 Ω-μm 2 .", "A fourth object of the present invention is to provide a MTJ element patterned using standard 180 nm photo-lithography and corresponding STT-RAM configured MRAM array of such elements, wherein the statistical distribution of MTJ resistances has a low covariance, preferably less than 5%.", "A fifth object of the present invention is to provide a MTJ element and corresponding STT-RAM configured MRAM array of such elements, wherein the read margin, (TMR/R p covariance), is greater than 15, and for an element of cross-sectional area 100 nm×150 nm is at least 20.", "A sixth object of the present invention is to provide such an MTJ element wherein the structure of the pinning/pinned layer provides a low angular dispersion of the pinned layer magnetic moment direction, preferably 1.6× less than that of conventional configurations.", "These objects will be met by an MTJ element structure in which the free layer damping constant (Gilbert damping constant a) is reduced to less than that associated with only a free layer of amorphous CoFeB, in which the tunnel barrier layer is deposited in a crystalline form by means of being sputtered from an Mg target and then naturally oxidized, in which highly efficient and enhanced spin polarization is obtained by surrounding the free layer by layers of crystalline Fe and in which the antiferromagnetic pinning layer is a layer of MnIr.", "The preferred structure of the MTJ element is of the form: Buffer layer/Pinning layer//Co 75 Fe 25 23/Ru7.5/Co 60 Fe 20 B 20 15-Co 75 Fe 25 (API)/Mg8-NOX-Mg4/Fee layer/Ta30/Ru Where the general ordering of the layers is as in FIG. 2 .", "In the preferred embodiment, the free layer is of the form Fe 3/CoFeB 20/Fe 6, with the two interfacial Fe layers being very thin (respectively 3 and 6 angstroms) and crystalline in structure for enhanced spin polarization of the current, while the CoFeB layer sandwiched between them is amorphous in form to obtain a low Gilbert magnetic damping factor.", "The tunneling barrier layer is a layer of MgO that is rendered crystalline in nature by being formed by a combination of a sputtering deposition of Mg and a natural oxidation process.", "The sputtering is onto an exposed surface of AP 1 that has been preconditioned by a plasma treatment to render it smooth/flat.", "This plasma pretreatment is, in turn, highly advantageous, given the fact that the pinning layer for the SyAF pinned layer is a layer of MnIr rather than the more usual MnPt.", "The MnIr pinning layer, in turn, allows an advantageous annealing process in which the anneal need only be carried out at 265° C. for between 1 and 2 hours in a magnetic field of 10 K Oe.", "It is to be noted that other prior art processes form the MgO tunneling barrier layer by sputtering directly from an MgO target.", "This produces an amorphous layer which must be rendered crystalline by use of much higher annealing temperatures than are required in the present invention.", "BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a prior-art MTJ MRAM device located at the junction of word and bit lines.", "FIG. 2 is a schematic cross-sectional view of a typical prior art spin-transfer device, including an MTJ element and current providing transistor, that, in the present invention, will utilize a novel combination of a pinning layer a tunneling barrier layer and a free layer.", "FIG. 3 a , FIG. 3 b and FIG. 3 c are schematic views of the fabrication of the layer structure of a preferred embodiment of the present invention FIG. 4 is a table showing the magnetic performance properties of various MTJ configurations.", "FIG. 5 a and FIG. 5 b are graphs showing characteristic B-H plots for an MTJ element incorporating an MnPt pinning layer ( FIG. 5 a ) and an MnIr pinning layer ( FIG. 5 b ).", "FIG. 6 is a graphical illustration of the distribution of Gilbert damping factors for various ternary compositions of Fe—Co—Ni alloy films.", "FIG. 7 is a graphical illustration of the variation of the Gilbert damping factor for Co—Fe—B films of various compositions.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the present invention is an STT-RAM memory cell and an array of such cells, in which each cell incorporates an MTJ element that operates in the spin torque transfer (STT) mode.", "The MTJ element includes an IrMn pinning layer, an SyAP pinned layer, a crystalline barrier layer of naturally oxidized MgO and a crystalline-Fe-sandwiched CoFeB free layer having Gilbert damping constants that are lower than those associated with free layers of only amorphous CoFeB.", "The preferred MTJ stack configuration is: BE/NiCr50/Ru20/MnIr70/Co 75 Fe 25 23(AP2)/Ru7.5/CoFeB 20 - Co 75 Fe 25 6-7 (AP1)/PT/ Mg8-NOX-Mg4/Fe3-Co 60 Fe 20 B 20 20-Fe6(FL)/Ta Referring to FIG. 3 a , FIGS. 3 b and 3 c , there will be schematically shown the process steps by which the stack configuration is formed.", "We will retain the essential elements of the numbering of FIG. 2 .", "Referring first to FIG. 3 a , there is shown the structure labeled BE above, which denotes a bottom conducting line or electrode ( 300 ).", "Layer ( 1 ) is a layer of NiCr, which is a seed layer.", "Layer ( 2 ) is the pinning layer, which is a layer of MnIr of 70 angstroms thickness.", "Layer ( 345 ) is the configuration Co 75 Fe 25 23(AP2)/Ru7.5/CoFeB 20 -Co 75 Fe 25 6-7 (AP 1 ) is a synthetic antiferromagnetic (SyAF) pinned layer, where AP 1 ( 5 ) and AP 2 ( 3 ) denote the two ferromagnetic layers magnetized in antiparallel directions and exchange coupled by the layer of Ru ( 4 ).", "As we shall explain below, PT denotes a plasma treatment ( 55 ) that is applied to the upper surface of AP 1 and is required to produce the desired objects of the invention.", "Referring next to FIG. 3 b , there is shown the formation of an MgO (or, similarly, an AlOx) barrier layer ( 6 ) on the plasma treated surface ( 555 ) of AP1.", "The plasma treatment, which smoothes and renders flat the ( 555 ) surface, is required because layers formed on a MnIr/SyAF combination such as in the present invention are typically rougher than when formed on an MnPt/SyAF combination.", "Consequently, dR/R and H e (H in ) pf the MnIr MTJ are not as good as that for the MnPt MTJ.", "To yield high dR/R and low H in , the CoFe(B)/MgO/CoFeB interfaces must be smooth.", "This is particularly true for the MTJ configuration where the very high dR/R is a result of coherent spin-dependent tunneling through the (001)CoFe(B)/(001)MgO/(001)CoFe(B) MTJ junctions.", "To prepare a smooth/flat bottom electrode (the bottom electrode denoting the entire portion of the element below the MgO tunneling barrier layer) prior to the MgO deposition, the plasma treatment (PT) process ( 55 ) has been applied to the exposed surface of AP 1 .", "PT is a low power (20W) Ar ion-milling process that smoothes and flattens the AP 1 surface.", "The ion energy is sufficiently low so that it does not damage the surface.", "Referring again to FIG. 3 b , the MgO barrier layer ( 6 ) is made by a process indicated above by Mg8-NOX-Mg4 and which is more fully described by Horng et al cited above.", "Unlike prior art processes, in which a target of MgO is sputtered and thereby produces an amorphous MgO layer, in the present process an Mg target is sputtered to produce a crystalline Mg layer and that already crystalline layer is then naturally oxidized after deposition to directly produce a crystalline MgO layer.", "A subsequent second Mg sputtering process completes the layer formation as described by Horng.", "In its as-deposited state, the naturally oxidized Mg already has a highly oriented (001) crystalline plane texture.", "In this respect, prior art rf-sputtered (extra-thin) MgO is deposited in an amorphous state and has to rely on subsequent high temperature (>350° C.) annealing processing to obtain a highly oriented (001) structure.", "Such high temperature annealing is not required in the present invention.", "Referring now to FIG. 3 c , there is shown the formation of the free layer of the present invention.", "The free layer ( 7 ) of the configuration above is a composite layer made of an atomic layer thickness (approximately 3 angstroms) crystalline Fe interface layer ( 71 ) and thicker, amorphous layer ( 72 ) of Co 60 Fe 20 B 20 (approximately 20 angstroms) formed upon it.", "More preferably, as is shown in the figure, an additional crystalline layer ( 73 ) of Fe approximately 6 angstroms in thickness can be inserted between the Co 60 Fe 20 B 20 and the Ta 30 capping layer ( 8 ).", "These two layers of Fe provide advantageous enhanced electron polarization properties at the interfaces between the MgO layer ( 6 ) and the free layer ( 7 ), between the AP 1 layer ( 5 ) and the MgO layer ( 6 ) and between the free layer ( 7 ) and the Ta layer ( 8 ).", "Finally, it is also noted from the evidence of FIG. 7 that a crystalline structure free layer of the form Fe(rich)—Co/Fe(rich)—Ni, which is a bilayer of two binary alloys that are rich in Fe, such as FeCo/FeNi can produce an even lower damping factor than the Fe/CoFeB/Fe free layer with amorphous CoFeB shown in the present FIG. 3 c and, in addition, when subjected to a >300° C. (e.g. 350° C.) post annealing can yield a dR/R=200% and a corresponding read margin that is >25.", "Such a free layer will, therefore, produce another preferred embodiment of the present invention.", "For comparison, we also made an STT-MTJ element in the configuration of Horng et al.", ", in which the pinning layer is MnPt and the free layer is only amorphous Co 60 Fe 20 B 20 , without the interfacial layers of Fe.", "To obtain the amorphous Co 60 Fe 20 B 20 layer the MTJ stack is processed using an (250-265° C.)-10KOe (1-2 hour) annealing treatment.", "Magnetic properties of the stack configurations are displayed in the table of FIG. 4 .", "It has already been noted here and will be discussed below, that forming the Co 60 Fe 20 B 20 on the atomic layer of Fe produces a higher degree of electron spin polarization than the amorphous layer alone.", "Referring again to FIG. 4 there is seen a table setting forth the magnetic properties of 7 MTJ stack configurations having the general form: Buffer layer/Pinning layer//Co 75 Fe 25 23/Ru7.5/Co 60 Fe 20 B 20 15-Co 75 Fe 25 (AP1)/ Mg8-NOX-Mg4/Fee layer/Ta30/Ru Row 1 shows the properties of the reference MTJ stack in which the pinning layer is MnPt and the free layer lacks the Fe crystalline layer and consists only of the amorphous CoFeB layer.", "Row 3 shows a similar structure except that the pinning layer is MnIr and the free layer includes the crystalline Fe layer.", "MR for row 1 is 103%, while for row 3 it is 118%.", "This improvement is attributed to the (001) Fe crystalline interface layer in the free layer structure.", "Due to a rougher bottom electrode, H e (H in ) for the MnIr-MTJ is 7.60 Oe, a twofold increase over the value of 3.73 Oe for the MnPt MTJ of the reference structure.", "Row 2 and Row 4 , which include a 120 sec.", "plasma treatment (PT) of the AP 1 surface, show that H e of both the MnPt and MnIr TMJ have been reduced to 2.48 and 4.41 Oe respectively.", "Having smooth/flat interfaces at the AP1/MgO/free layer enhances the MR for both the MnPt and MnIr structures.", "For 100 nm×150 nm MTJ elements, MR (at 0.1 V bias read operation) for the MnIr MTJ would be about 100%.", "To meet the read margin requirement of TMR/(R p covariance) >20, the covariance would have to be less than or equal to 5%.", "To obtain an amorphous CoFeB layer for its low magnetization damping and low M s , the deposited MTJ stack is annealed using a 265° C. (1-2 hrs) 10K Oe process.", "Previously, in GMR sensor head fabrication, to obtain a robust MnPt/SyAF pinned layer, post deposition annealing to the MTJ stack was done in a 280° C. (5 hrs)-10 K Oe process.", "Post deposition annealing for the MnIr/SyAF MTJ, however, is at 250°-265° C. (5 hrs)-10 K Oe.", "It appears that the 265° C. (1-2 hrs)10K Oe process is more suitable for the MnIr pinning layer structure than for the MnPt pinning structure.", "In terms of TMR magnetic performance, the MnIr MTJ element is preferred.", "Referring now to FIGS. 5 a and 5 b , there is shown the B-H characteristic plots for the MTJ element made (in 5 a ) for the MnPt pinning layer and ( 5 b ) for the MnIr pinning layer.", "The open loop portion of each curve (arrows) allows us to deduce the pinned layer dispersion and the strength of the pinning field for the MnIr MTJ and for the MnPt MTJ.", "Thus the ratio of H pin (MnIr)/H pin (MnPt) is approximately 1.6.", "The ratio of dispersion (MnPt)/dispersion (MnIr) is about 1.6.", "From this, we can also deduce that the covariance ratio of [R p cov.", "(MnPt)/R p cov (MnIr)] is about 1.6.", "Using [R p cov.", "(MnPt)]=7.5% given by Horng et al, we can deduce that [R p cov.", "(MnIr)]=4.7%, which is in close agreement to Headway Technology's measured MnIr stack covariance for their TMR sensor made with a MnIr pinning layer (described above).", "Referring to FIG. 6 , it is noted that the boron (B) doping to the CoFe free layer has enhanced the magnetization damping.", "Use of the Fe crystalline interface layers provides high spin polarization (higher than from the amorphous CoFeB layer alone).", "As can be seen in FIG. 7 , the damping constant of Fe is α=0.0019 and the damping constant of Co 60 Fe 20 B 20 is α=0.01.", "The effective damping constant for the composite free layer of Fe/Co 60 Fe 20 B 20 /Fe (with the thicknesses of the two Fe layers being approximately 3 and 6 angstroms respectively and the thickness of the Co 60 Fe 20 B 20 being approximately 20 ang.) is calculated to be α=0.006, which will produce the required improvement of the critical current for magnetic moment switching.", "It is further noted that an even smaller damping constant can be obtained using a free layer of Fe/Co 40 Fe 40 B 20 /Fe (same Fe thicknesses, but the sandwiched layer of CoFeB being approximately 15 angstroms) since the damping constant of Co 40 Fe 40 B 20 is α=0.0038, which is smaller than the α=0.01 of the Co 60 Fe 20 B 20 .", "As is finally understood by a person skilled in the art, the preferred embodiments of the present invention are illustrative of the present invention rather than limiting of the present invention.", "Revisions and modifications may be made to methods, materials, structures and dimensions employed in forming and providing a CPP STT-MTJ MRAM cell, said cell using transfer of spin angular momentum, while still forming and providing such a cell and its method of formation in accord with the spirit and scope of the present invention as defined by the appended claims." ]
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method of forming a local mobility domain (LMD) and a local mobility agent (LMA). More particularly, the present invention relates to a method of forming an LMD and an LMA based on Mobile IP and an apparatus thereof. [0003] 2. Description of the Related Art [0004] As the Internet has grown and as users have become more interested in mobile Internet access, the number of available IP addresses for network devices is decreasing. With drawbacks of the existing IPv4 becoming more evident, a new protocol, known as IPv6, has been defined. [0005] Conventional mobile terminals, having access to the Internet under IPv6, each have a fixed home address and a home agent (HA). When the mobile terminal moves to a network other than the home network, the mobile terminal receives a care-of-address (COA), which represents a new location of the mobile terminal. [0006] Referring to a conventional system shown in FIGS. 1 and 2, a mobile node (MN) reports the care-of-address to a home agent. Thereafter, data targeting the MN is input to the home network of the MN where it is received by the HA and transferred to the COA for the MN. In the following figures, the abbreviations AR, CN, MN, and BU denote an access router, a correspondent node, a mobile node, and a binding update, respectively. [0007] In the case that the home network (HOME N/W) is far from a present network, such as the foreign networks (FOREIGN N/W) indicated in FIGS. 1 and 2, it is inconvenient to register every movement of the MN to the HA. For such cases, each network is divided into LMDs, each domain containing an LMA, which operates as a local HA. In an LMD, the MN receives a regional care-of-address (RCOA) and a local care-of-address (LCOA). In this case, the RCOA represents the location of the LMA in the LMD, and the LCOA represents the present location of the MN. [0008] With reference to FIGS. 3 through 6, an MN registers a present location and the location of a present LMA to a home LMA and the HA, respectively. When data targeting the MN is input to the home network, the HA sends the data to the present LMA of the MN and the present LMA transfers the data to the MN, as shown in FIG. 4. If the MN moves within the LMD, the MN registers a new location to the home LMA, as shown in FIG. 5. The data transferred to the MN is transferred through the HA, the new LMA, and a new access router (AR), as shown in FIG. 6. [0009] According to a conventional protocol, a network manager establishes the LMD and LMA. However, since it is difficult to correct the LMD according to changes of the networks, the LMA may become the point of failure for the entire network. SUMMARY OF THE INVENTION [0010] In an effort to solve the above-described problems, it is a feature of an embodiment of the present invention to provide a method and apparatus for establishing a local mobility domain (LMD) and a local mobility agent (LMA) according to a movement of a mobile node (MN). [0011] According to an embodiment of the present invention, a method of forming an LMD preferably includes: (a) establishing a hop-count from a center router (CR) for a predetermined value; (b) generating a list of access routers (ARs) within a domain defined by the established hop-count while surrounding a predetermined AR; and (c) establishing the ARs included in the list as an LMD, which has the predetermined AR as the CR. [0012] According to another embodiment of the present invention, a method of forming a LMA preferably includes: (a) establishing an LMD; and (b) establishing an AR to which an MN has a first access as the LMA in order to register a local care-of-address (LCOA) and a regional care-of-address (RCOA) to a home agent (HA) and the LMA, when the MN has accessed a predetermined LMD. Preferably, the method of forming the LMA may further include: (c) determining the existence of the LMA in an LMD list of the AR, which the MN has newly accessed, to register a new LCOA to the LMA, when the MN moves. Here, (c) may further include establishing the AR, which the MN has newly accessed, as a new LMA to register new LCOA and RCOA to the HA and the new LMA, respectively, when the LMA is absent from the LMD list of the AR, which the MN has newly accessed. The method of forming the LMA may further include: (d) establishing the present AR as a new LMA to register a new LCOA and RCOA to the HA and the new LMA, respectively, when the MN exceeds a predetermined binding lifetime and a number of binding update messages (BUM) exceeds a predetermined value. The foregoing methods, individually and in combination are preferably operated under control of a computer using a stored program. [0013] In a system for implementing the foregoing methods, a router preferably includes: a hop-count establishment unit for receiving and storing a hop-count; an LMD list generation unit for generating and storing a list of the neighboring routers, which have a hop-count from the router of less than a predetermined value, thereby defining an LMD; and an address management unit for receiving and storing an RCOA and an LCOA from an MN in the case that the router is established as the LMA. In an embodiment of the present invention, an MN preferably includes: an LMA control unit for deciding whether to establish a present AR to which an MN has an access as an LMA and for receiving and storing a list of the AR established as the LMA; an address register unit for registering an RCOA and an LCOA to an HA and the LMA, respectively; and an LMA service time adjustment unit for establishing the present AR to which the MN has an access as a new LMA when a binding lifetime has passed and a number of BUMs exceeds a predetermined value. [0014] According to an embodiment of the present invention, a system for establishing an LMA and an LMD preferably includes a router and an MN. In this embodiment, the router preferably includes: a hop-count establishment unit for receiving and storing a hop-count; a LMD list generation unit for establishing routers within a domain, which has a hop-count less than a predetermined value from a router, as an LMD to generate and store a list of the routers within the LMD; and an address management unit for receiving and storing an RCOA and an LCOA from the MN in the case that the router is established as the LMA. The MN preferably includes: an LMA control unit for deciding whether to establish the present router to which the MN has an access as the LMA and for receiving and storing a list of the routers established as the LMA; an address register unit for registering the RCOA and the LCOA to an HA and the LMA, respectively; and an LMA service time adjustment unit for establishing the present routers to which the MN has an access as a new LMA when a binding lifetime has passed and a number of BUMs exceeds a predetermined value. [0015] Further features of the present invention will become apparent from a description of the fabrication process and a structure resulting therefrom, taken in conjunction with the accompanying drawings of the preferred embodiment of the invention. The disclosed preferred embodiments, however, should not be taken to be limiting on the present invention. [0016] These and other features and aspects of the present invention will be readily apparent to those of ordinary skill in the art upon review of the detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS [0017] The above features and advantages of the present invention will become more apparent to those skilled in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which: [0018] [0018]FIG. 1 illustrates a conventional system implementation for registering a mobile terminal using IPv6; [0019] [0019]FIG. 2 illustrates conventional data transfer paths when using a mobile terminal; [0020] [0020]FIG. 3 illustrates communication paths for registering in a conventional localized mobility management system; [0021] [0021]FIG. 4 illustrates communication paths for transferring localized mobility management data; [0022] [0022]FIG. 5 illustrates a method of registering in a conventional localized mobility management system when a mobile node (MN) is moving; [0023] [0023]FIG. 6 illustrates communication paths for transferring data in a conventional localized mobility management system when the MN is moving; [0024] [0024]FIG. 7 illustrates a local mobility domain (LMD) according to an embodiment of the present invention; [0025] [0025]FIG. 8 illustrates a method of constituting an LMD and a local mobility agent (LMA) when a mobile node (MN) has first accessed a network according to an embodiment of the present invention; [0026] [0026]FIG. 9 illustrates a method of constituting an LMD and an LMA when the MN moves within an LMD according to an embodiment of the present invention; [0027] [0027]FIG. 10 illustrates a method of constituting an LMD and an LMA when the MN moves out of an LMD according to an embodiment of the present invention; [0028] [0028]FIG. 11 is a flowchart for explaining a method of forming an LMD and an LMA according to an embodiment of the present invention; [0029] [0029]FIG. 12 illustrates a system for establishing an LMA according to an embodiment of the present invention; and [0030] [0030]FIG. 13 illustrates a method of re-establishing an LMA due to a local mobility management time-out according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0031] Korean Patent Application No. 2001-45485, filed Jul. 27, 2001, and entitled “Method of Forming a Local Mobility Domain and a Local Mobility Agent and Apparatus Thereof,” is incorporated by reference herein in its entirety. [0032] The present invention will be described with reference to attached drawings. As described above, abbreviations AR, CN, MN, BU, COA, RCOA, LCOA, and LMD denote an access router, a correspondent node, a mobile node, a binding update, a care-of-address, a regional care-of-address, a local care-of-address, and a local mobility domain, respectively. [0033] [0033]FIG. 7 illustrates an LMD according to the present invention, which preferably includes a center router and a plurality of routers within a short distance of the center router. The distance between the routers is measured by hop-count. In this case, a hop is a path for transferring a data packet from a router to another router in a packet interchange type network. [0034] The hop-count for transferring one packet to a target position is stored in a packet header in a network, such as that in an Internet network using Transport Communication Protocol/Internet Protocol (TCP/IP). [0035] An LMD may be represented as LMD(CR, N), wherein, CR stands for a center router and N stands for a natural number. Accordingly, the LMD(CR, N) stands for an assemblage of routers that exist within the hop-count of a natural number N from a center router. For example, as shown in FIG. 7, an LMD(AR 1 , 2 ) is represented as a circle that surrounds an AR 1 . The CRs of each LMD become the LMAs of the LMDs. For example, the AR 1 in the LMD(AR 1 , 2 ) becomes the LMA as shown in FIG. 7. [0036] A network manager establishes the natural number N to select the size of the LMD. The network manager may change the natural number N according to the state of the network in order to vary the size of the LMD. After the natural number N is selected, the LMD is firmly fixed by the CR. [0037] Each AR generates an LMD list, which specifies the ARs within a distance that is defined by the natural number N from each AR. Each AR has a different LMD list. [0038] [0038]FIG. 8 illustrates a method of constituting an LMD and an LMA when the MN has first accessed a network according to the present invention. [0039] When the MN is introduced into a new network, the first AR to which the MN has had a first access becomes a first LMA of the MN. Then, a first LMD is constituted according to the first LMA. The MN registers an LCOA and an RCOA to a home agent (HA) and the first LMA, respectively. Then, data targeting the MN is transferred through the HA and the first LMA. [0040] [0040]FIG. 9 illustrates a method of constituting an LMD and an LMA when the MN moves within the first LMD according to the present invention. [0041] When the MN moves from the first AR to a second AR, the MN checks for the existence of the first LMA in the LMD list of the new second AR. The existence of the first LMA in the LMD list of the second AR means that the MN has moved within the first LMD, therefore the MN registers a new LCOA to the first LMA. [0042] [0042]FIG. 10 illustrates a method of constituting an LMD and an LMA when the MN moves out of an LMD according to the present invention. When the MN moves from the first AR to a third AR, the MN checks for the existence of the first LMA in the LMD list of the third AR. The absence of the first LMA from the LMD list of the third AR means that the MN has moved outside of the first LMD. Consequently, the third AR becomes a new (i.e., a second) LMA, and the MN registers new RCOA and LCOA to the HA and the second LMA, respectively, as in the case where the MN had the first access to the network, as discussed with reference to FIG. 8. [0043] [0043]FIG. 11 is a flowchart of a preferred method of forming an LMD and an LMA according to an embodiment of the present invention. In step 1101 , a hop-count for LMDs is established by a predetermined value N. In step 1102 , for each AR, a list of neighboring ARs having a hop-count less than the value N from the AR is generated and stored to establish an LMD. When an MN has accessed a predetermined LMD in step 1103 , the AR to which the MN has had a first access is established as an LMA in order to register an RCOA and an LCOA to an HA and the LMA, respectively, in step 1104 . Then, in step 1105 , any movement of the MN is checked. In the case that the MN has moved and a new AR has been contacted, in step 1106 , the existence of the existing LMA is checked in the LMD list of the new AR. If the present LMA exists in the LMD list of the new AR, in step 1108 , the MN registers a new LCOA to the present LMA. In the case that the present LMA is absent from the LMD list of the new AR, the MN establishes the new AR as a new LMA, in step 1107 , and registers a new LCOA and RCOA to the HA and the new LMA, respectively. Step 1105 is then repeated. In the case that the MN has not moved, step 1105 is repeated. [0044] [0044]FIG. 12 illustrates a preferred embodiment of a system for establishing an LMA according to the present invention. The system includes a router 1201 having a hop-count establishment unit 12011 , an LMD list generation unit 12012 , and an address management unit 12013 , and an MN 1202 having an LMA control unit 12021 , an address register unit 12022 , and an LMA service time adjustment unit 12023 . [0045] In this system, the hop-count establishment unit 12011 receives and stores variations in the neighboring hops from a network manager. The LMD list generation unit 12012 searches ARs within a domain defined by a hop-count of the hop-count establishment unit 12011 to generate and store a list of the ARs, thereby determining the size of an LMD. The address management unit 12013 receives and stores an RCOA and an LCOA from the MN 1202 in order to transfer the RCOA to the HA. [0046] When the MN 1202 is first introduced into a network, the LMA control unit 12021 establishes the AR to which the MN 1202 has a first access as an LMA. After the MN 1202 has moved, the LMA control unit 12021 determines the existence of the existing LMA in the LMD list of a new AR. In the case that the LMA exists in the LMD list of the new AR, the LMA control unit 12021 retains the existing LMA. Alternatively, the LMA control unit 12021 establishes the new AR as a new LMA. Then, the address register unit 12022 receives a new RCOA and LCOA in order to transfer and register to the LMA and the HA. When the MN 1202 has moved within the LMD, the address register unit 12022 transfers and registers the LCOA to the LMA, while storing the RCOA and LCOA. [0047] According to the present invention, the use of a particular AR as an LMA by an MN may need to be limited, particularly after several moves within a same LMD, in which the same LMA is retained at each move. Thus, a timeout mechanism is preferably included as LMA service time adjustment unit 12023 in MN 1202 to allow for periodic updates of the LMA for a moving MN. [0048] In a case where a predetermined binding lifetime (i.e., a timeout) has passed and a number of binding update messages (BUMs) that are sent to re-initialize the timeout mechanism exceeds a predetermine value, the LMA service time adjustment unit 12023 establishes the present (i.e., the latest) AR as a new LMA. FIG. 13 illustrates an exemplary operation of the LMA service time adjustment unit 12023 according to the present invention. [0049] Referring to FIG. 13, after a local mobility management time-out (steps 1301 and 1302 ,) a new LMA is established in step 1304 . The service time is checked by counting a time limit field of a binding update and a number of BUMs that are transferred to the LMA. After transferring a predetermined number of BUMs, the present AR becomes a new LMA and the MN registers a new address to the HA. [0050] Specifically, in step 1301 , a binding lifetime is checked to determine whether the binding lifetime has surpassed a predetermined value. If the binding lifetime has elapsed, in step 1302 , the number of BUMs is tested against a predetermined binding limit. When the number of the BUMs is greater than the predetermined binding limit, the MN registers a new CR and registers a present address to the HA while initializing the number of the BUMs to zero. When the number of the BUMs is equal to or less than the predetermined binding limit, in step 1306 , the MN increments the BUM count and a BUM is sent to the LMA. [0051] The above-described present invention may be organized into a program recorded on media, so as to be operated in a common digital computer. The examples of the media include magnetic recording media, i.e., ROMs, floppy disks, and hard disks, optical recording media, i.e., CD-ROMs, and DVDs, and carrier waves, i.e., transfer through the Internet. [0052] As a result, the present invention does not require manual establishment of an LMD and an LMA in a localized mobility management system and actively varies the LMD according to changes in the network in order to improve convenience and efficiency in a network. In addition, the AR may be used as an LMA to distribute load on the network. [0053] In order to prevent loading on the LMA caused by the MN, a time limit for receiving service from the LMA may be set in the MN. This may be realized in the MN without affecting the network protocol in order to improve the entire performance of the network as well as the performance of the AR. [0054] Preferred embodiments of the present invention have been disclosed herein and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
An automated system and method of establishing a local mobility domain (LMD) and a local mobility agent (LMA) on a mobile terminal node (MN) using Internet Protocol version (IPv6) preferably includes: establishing within the MN a newly contacted access router (AR) as the LMA and then receiving from the LMA and storing a list of neighboring ARs, which comprise the LMD. Each AR contains a stored list of neighboring ARs that are within a predetermined range of the AR, which is dynamically set by a network manager. The MN registers a retrieved local and regional address with both the LMA and a home agent (HA.) When the MN moves to a new AR, the stored list of the new AR is checked for the present LMA. The LMA is only changed to the new AR and re-registered with the HA if the new AR is in a different LMD.
Summarize the information, clearly outlining the challenges and proposed solutions.
[ "BACKGROUND OF THE INVENTION [0001] 1.", "Field of the Invention [0002] The present invention relates to a method of forming a local mobility domain (LMD) and a local mobility agent (LMA).", "More particularly, the present invention relates to a method of forming an LMD and an LMA based on Mobile IP and an apparatus thereof.", "[0003] 2.", "Description of the Related Art [0004] As the Internet has grown and as users have become more interested in mobile Internet access, the number of available IP addresses for network devices is decreasing.", "With drawbacks of the existing IPv4 becoming more evident, a new protocol, known as IPv6, has been defined.", "[0005] Conventional mobile terminals, having access to the Internet under IPv6, each have a fixed home address and a home agent (HA).", "When the mobile terminal moves to a network other than the home network, the mobile terminal receives a care-of-address (COA), which represents a new location of the mobile terminal.", "[0006] Referring to a conventional system shown in FIGS. 1 and 2, a mobile node (MN) reports the care-of-address to a home agent.", "Thereafter, data targeting the MN is input to the home network of the MN where it is received by the HA and transferred to the COA for the MN.", "In the following figures, the abbreviations AR, CN, MN, and BU denote an access router, a correspondent node, a mobile node, and a binding update, respectively.", "[0007] In the case that the home network (HOME N/W) is far from a present network, such as the foreign networks (FOREIGN N/W) indicated in FIGS. 1 and 2, it is inconvenient to register every movement of the MN to the HA.", "For such cases, each network is divided into LMDs, each domain containing an LMA, which operates as a local HA.", "In an LMD, the MN receives a regional care-of-address (RCOA) and a local care-of-address (LCOA).", "In this case, the RCOA represents the location of the LMA in the LMD, and the LCOA represents the present location of the MN.", "[0008] With reference to FIGS. 3 through 6, an MN registers a present location and the location of a present LMA to a home LMA and the HA, respectively.", "When data targeting the MN is input to the home network, the HA sends the data to the present LMA of the MN and the present LMA transfers the data to the MN, as shown in FIG. 4. If the MN moves within the LMD, the MN registers a new location to the home LMA, as shown in FIG. 5. The data transferred to the MN is transferred through the HA, the new LMA, and a new access router (AR), as shown in FIG. 6. [0009] According to a conventional protocol, a network manager establishes the LMD and LMA.", "However, since it is difficult to correct the LMD according to changes of the networks, the LMA may become the point of failure for the entire network.", "SUMMARY OF THE INVENTION [0010] In an effort to solve the above-described problems, it is a feature of an embodiment of the present invention to provide a method and apparatus for establishing a local mobility domain (LMD) and a local mobility agent (LMA) according to a movement of a mobile node (MN).", "[0011] According to an embodiment of the present invention, a method of forming an LMD preferably includes: (a) establishing a hop-count from a center router (CR) for a predetermined value;", "(b) generating a list of access routers (ARs) within a domain defined by the established hop-count while surrounding a predetermined AR;", "and (c) establishing the ARs included in the list as an LMD, which has the predetermined AR as the CR.", "[0012] According to another embodiment of the present invention, a method of forming a LMA preferably includes: (a) establishing an LMD;", "and (b) establishing an AR to which an MN has a first access as the LMA in order to register a local care-of-address (LCOA) and a regional care-of-address (RCOA) to a home agent (HA) and the LMA, when the MN has accessed a predetermined LMD.", "Preferably, the method of forming the LMA may further include: (c) determining the existence of the LMA in an LMD list of the AR, which the MN has newly accessed, to register a new LCOA to the LMA, when the MN moves.", "Here, (c) may further include establishing the AR, which the MN has newly accessed, as a new LMA to register new LCOA and RCOA to the HA and the new LMA, respectively, when the LMA is absent from the LMD list of the AR, which the MN has newly accessed.", "The method of forming the LMA may further include: (d) establishing the present AR as a new LMA to register a new LCOA and RCOA to the HA and the new LMA, respectively, when the MN exceeds a predetermined binding lifetime and a number of binding update messages (BUM) exceeds a predetermined value.", "The foregoing methods, individually and in combination are preferably operated under control of a computer using a stored program.", "[0013] In a system for implementing the foregoing methods, a router preferably includes: a hop-count establishment unit for receiving and storing a hop-count;", "an LMD list generation unit for generating and storing a list of the neighboring routers, which have a hop-count from the router of less than a predetermined value, thereby defining an LMD;", "and an address management unit for receiving and storing an RCOA and an LCOA from an MN in the case that the router is established as the LMA.", "In an embodiment of the present invention, an MN preferably includes: an LMA control unit for deciding whether to establish a present AR to which an MN has an access as an LMA and for receiving and storing a list of the AR established as the LMA;", "an address register unit for registering an RCOA and an LCOA to an HA and the LMA, respectively;", "and an LMA service time adjustment unit for establishing the present AR to which the MN has an access as a new LMA when a binding lifetime has passed and a number of BUMs exceeds a predetermined value.", "[0014] According to an embodiment of the present invention, a system for establishing an LMA and an LMD preferably includes a router and an MN.", "In this embodiment, the router preferably includes: a hop-count establishment unit for receiving and storing a hop-count;", "a LMD list generation unit for establishing routers within a domain, which has a hop-count less than a predetermined value from a router, as an LMD to generate and store a list of the routers within the LMD;", "and an address management unit for receiving and storing an RCOA and an LCOA from the MN in the case that the router is established as the LMA.", "The MN preferably includes: an LMA control unit for deciding whether to establish the present router to which the MN has an access as the LMA and for receiving and storing a list of the routers established as the LMA;", "an address register unit for registering the RCOA and the LCOA to an HA and the LMA, respectively;", "and an LMA service time adjustment unit for establishing the present routers to which the MN has an access as a new LMA when a binding lifetime has passed and a number of BUMs exceeds a predetermined value.", "[0015] Further features of the present invention will become apparent from a description of the fabrication process and a structure resulting therefrom, taken in conjunction with the accompanying drawings of the preferred embodiment of the invention.", "The disclosed preferred embodiments, however, should not be taken to be limiting on the present invention.", "[0016] These and other features and aspects of the present invention will be readily apparent to those of ordinary skill in the art upon review of the detailed description that follows.", "BRIEF DESCRIPTION OF THE DRAWINGS [0017] The above features and advantages of the present invention will become more apparent to those skilled in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which: [0018] [0018 ]FIG. 1 illustrates a conventional system implementation for registering a mobile terminal using IPv6;", "[0019] [0019 ]FIG. 2 illustrates conventional data transfer paths when using a mobile terminal;", "[0020] [0020 ]FIG. 3 illustrates communication paths for registering in a conventional localized mobility management system;", "[0021] [0021 ]FIG. 4 illustrates communication paths for transferring localized mobility management data;", "[0022] [0022 ]FIG. 5 illustrates a method of registering in a conventional localized mobility management system when a mobile node (MN) is moving;", "[0023] [0023 ]FIG. 6 illustrates communication paths for transferring data in a conventional localized mobility management system when the MN is moving;", "[0024] [0024 ]FIG. 7 illustrates a local mobility domain (LMD) according to an embodiment of the present invention;", "[0025] [0025 ]FIG. 8 illustrates a method of constituting an LMD and a local mobility agent (LMA) when a mobile node (MN) has first accessed a network according to an embodiment of the present invention;", "[0026] [0026 ]FIG. 9 illustrates a method of constituting an LMD and an LMA when the MN moves within an LMD according to an embodiment of the present invention;", "[0027] [0027 ]FIG. 10 illustrates a method of constituting an LMD and an LMA when the MN moves out of an LMD according to an embodiment of the present invention;", "[0028] [0028 ]FIG. 11 is a flowchart for explaining a method of forming an LMD and an LMA according to an embodiment of the present invention;", "[0029] [0029 ]FIG. 12 illustrates a system for establishing an LMA according to an embodiment of the present invention;", "and [0030] [0030 ]FIG. 13 illustrates a method of re-establishing an LMA due to a local mobility management time-out according to an embodiment of the present invention.", "DETAILED DESCRIPTION OF THE INVENTION [0031] Korean Patent Application No. 2001-45485, filed Jul. 27, 2001, and entitled “Method of Forming a Local Mobility Domain and a Local Mobility Agent and Apparatus Thereof,” is incorporated by reference herein in its entirety.", "[0032] The present invention will be described with reference to attached drawings.", "As described above, abbreviations AR, CN, MN, BU, COA, RCOA, LCOA, and LMD denote an access router, a correspondent node, a mobile node, a binding update, a care-of-address, a regional care-of-address, a local care-of-address, and a local mobility domain, respectively.", "[0033] [0033 ]FIG. 7 illustrates an LMD according to the present invention, which preferably includes a center router and a plurality of routers within a short distance of the center router.", "The distance between the routers is measured by hop-count.", "In this case, a hop is a path for transferring a data packet from a router to another router in a packet interchange type network.", "[0034] The hop-count for transferring one packet to a target position is stored in a packet header in a network, such as that in an Internet network using Transport Communication Protocol/Internet Protocol (TCP/IP).", "[0035] An LMD may be represented as LMD(CR, N), wherein, CR stands for a center router and N stands for a natural number.", "Accordingly, the LMD(CR, N) stands for an assemblage of routers that exist within the hop-count of a natural number N from a center router.", "For example, as shown in FIG. 7, an LMD(AR 1 , 2 ) is represented as a circle that surrounds an AR 1 .", "The CRs of each LMD become the LMAs of the LMDs.", "For example, the AR 1 in the LMD(AR 1 , 2 ) becomes the LMA as shown in FIG. 7. [0036] A network manager establishes the natural number N to select the size of the LMD.", "The network manager may change the natural number N according to the state of the network in order to vary the size of the LMD.", "After the natural number N is selected, the LMD is firmly fixed by the CR.", "[0037] Each AR generates an LMD list, which specifies the ARs within a distance that is defined by the natural number N from each AR.", "Each AR has a different LMD list.", "[0038] [0038 ]FIG. 8 illustrates a method of constituting an LMD and an LMA when the MN has first accessed a network according to the present invention.", "[0039] When the MN is introduced into a new network, the first AR to which the MN has had a first access becomes a first LMA of the MN.", "Then, a first LMD is constituted according to the first LMA.", "The MN registers an LCOA and an RCOA to a home agent (HA) and the first LMA, respectively.", "Then, data targeting the MN is transferred through the HA and the first LMA.", "[0040] [0040 ]FIG. 9 illustrates a method of constituting an LMD and an LMA when the MN moves within the first LMD according to the present invention.", "[0041] When the MN moves from the first AR to a second AR, the MN checks for the existence of the first LMA in the LMD list of the new second AR.", "The existence of the first LMA in the LMD list of the second AR means that the MN has moved within the first LMD, therefore the MN registers a new LCOA to the first LMA.", "[0042] [0042 ]FIG. 10 illustrates a method of constituting an LMD and an LMA when the MN moves out of an LMD according to the present invention.", "When the MN moves from the first AR to a third AR, the MN checks for the existence of the first LMA in the LMD list of the third AR.", "The absence of the first LMA from the LMD list of the third AR means that the MN has moved outside of the first LMD.", "Consequently, the third AR becomes a new (i.e., a second) LMA, and the MN registers new RCOA and LCOA to the HA and the second LMA, respectively, as in the case where the MN had the first access to the network, as discussed with reference to FIG. 8. [0043] [0043 ]FIG. 11 is a flowchart of a preferred method of forming an LMD and an LMA according to an embodiment of the present invention.", "In step 1101 , a hop-count for LMDs is established by a predetermined value N. In step 1102 , for each AR, a list of neighboring ARs having a hop-count less than the value N from the AR is generated and stored to establish an LMD.", "When an MN has accessed a predetermined LMD in step 1103 , the AR to which the MN has had a first access is established as an LMA in order to register an RCOA and an LCOA to an HA and the LMA, respectively, in step 1104 .", "Then, in step 1105 , any movement of the MN is checked.", "In the case that the MN has moved and a new AR has been contacted, in step 1106 , the existence of the existing LMA is checked in the LMD list of the new AR.", "If the present LMA exists in the LMD list of the new AR, in step 1108 , the MN registers a new LCOA to the present LMA.", "In the case that the present LMA is absent from the LMD list of the new AR, the MN establishes the new AR as a new LMA, in step 1107 , and registers a new LCOA and RCOA to the HA and the new LMA, respectively.", "Step 1105 is then repeated.", "In the case that the MN has not moved, step 1105 is repeated.", "[0044] [0044 ]FIG. 12 illustrates a preferred embodiment of a system for establishing an LMA according to the present invention.", "The system includes a router 1201 having a hop-count establishment unit 12011 , an LMD list generation unit 12012 , and an address management unit 12013 , and an MN 1202 having an LMA control unit 12021 , an address register unit 12022 , and an LMA service time adjustment unit 12023 .", "[0045] In this system, the hop-count establishment unit 12011 receives and stores variations in the neighboring hops from a network manager.", "The LMD list generation unit 12012 searches ARs within a domain defined by a hop-count of the hop-count establishment unit 12011 to generate and store a list of the ARs, thereby determining the size of an LMD.", "The address management unit 12013 receives and stores an RCOA and an LCOA from the MN 1202 in order to transfer the RCOA to the HA.", "[0046] When the MN 1202 is first introduced into a network, the LMA control unit 12021 establishes the AR to which the MN 1202 has a first access as an LMA.", "After the MN 1202 has moved, the LMA control unit 12021 determines the existence of the existing LMA in the LMD list of a new AR.", "In the case that the LMA exists in the LMD list of the new AR, the LMA control unit 12021 retains the existing LMA.", "Alternatively, the LMA control unit 12021 establishes the new AR as a new LMA.", "Then, the address register unit 12022 receives a new RCOA and LCOA in order to transfer and register to the LMA and the HA.", "When the MN 1202 has moved within the LMD, the address register unit 12022 transfers and registers the LCOA to the LMA, while storing the RCOA and LCOA.", "[0047] According to the present invention, the use of a particular AR as an LMA by an MN may need to be limited, particularly after several moves within a same LMD, in which the same LMA is retained at each move.", "Thus, a timeout mechanism is preferably included as LMA service time adjustment unit 12023 in MN 1202 to allow for periodic updates of the LMA for a moving MN.", "[0048] In a case where a predetermined binding lifetime (i.e., a timeout) has passed and a number of binding update messages (BUMs) that are sent to re-initialize the timeout mechanism exceeds a predetermine value, the LMA service time adjustment unit 12023 establishes the present (i.e., the latest) AR as a new LMA.", "FIG. 13 illustrates an exemplary operation of the LMA service time adjustment unit 12023 according to the present invention.", "[0049] Referring to FIG. 13, after a local mobility management time-out (steps 1301 and 1302 ,) a new LMA is established in step 1304 .", "The service time is checked by counting a time limit field of a binding update and a number of BUMs that are transferred to the LMA.", "After transferring a predetermined number of BUMs, the present AR becomes a new LMA and the MN registers a new address to the HA.", "[0050] Specifically, in step 1301 , a binding lifetime is checked to determine whether the binding lifetime has surpassed a predetermined value.", "If the binding lifetime has elapsed, in step 1302 , the number of BUMs is tested against a predetermined binding limit.", "When the number of the BUMs is greater than the predetermined binding limit, the MN registers a new CR and registers a present address to the HA while initializing the number of the BUMs to zero.", "When the number of the BUMs is equal to or less than the predetermined binding limit, in step 1306 , the MN increments the BUM count and a BUM is sent to the LMA.", "[0051] The above-described present invention may be organized into a program recorded on media, so as to be operated in a common digital computer.", "The examples of the media include magnetic recording media, i.e., ROMs, floppy disks, and hard disks, optical recording media, i.e., CD-ROMs, and DVDs, and carrier waves, i.e., transfer through the Internet.", "[0052] As a result, the present invention does not require manual establishment of an LMD and an LMA in a localized mobility management system and actively varies the LMD according to changes in the network in order to improve convenience and efficiency in a network.", "In addition, the AR may be used as an LMA to distribute load on the network.", "[0053] In order to prevent loading on the LMA caused by the MN, a time limit for receiving service from the LMA may be set in the MN.", "This may be realized in the MN without affecting the network protocol in order to improve the entire performance of the network as well as the performance of the AR.", "[0054] Preferred embodiments of the present invention have been disclosed herein and, although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation.", "Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims." ]
FIELD OF THE INVENTION The present invention relates to noise attenuation panels and is particularly, although not exclusively, concerned with noise attenuation panels for use in the attenuation of noise in aero engines. DESCRIPTION OF THE BACKGROUND ART In patent application publication GB-A- 2223448 there is disclosed a noise attenuation panel having a backing component part, a facing component part and a cellular component part having a multiplicity of open-ended juxtaposed cells, the backing component part extending across the ends of the cells of the cellular component part at the rear thereof and the facing component part extending across the ends of the cells of the cellular component part at the front thereof. In addition, the facing component part comprises or includes an outer facing sheet which is made of a porous permeable thermoplastics material. Preferably, the porous permeable thermoplastics material is produced by powder sintering of a thermoplastics materials. In one embodiment of the invention described in GB-A-2223448, the cellular component part comprises a single cellular element having wall portions which extend across the element from the front face thereof to the rear face thereof and which provide bounding surfaces for an array of open-ended juxtaposed cells. In another embodiment of the invention described in GB-A-2223448, the cellular component part is sub-divided into a front cellular element and a rear cellular element positioned to the rear of the front cellular element with a septum element extending between the two cellular elements. Each cellular element has wall portions which extend across the element from the front face thereof to the rear face thereof and which provide bounding surfaces for an array of open-ended juxtaposed cells. While the panel disclosed in GB-A-2223448 has been found to be successful for use in aero engine environments, drawbacks may be found in using a cellular component part formed as a single cellular element or as two cellular elements in which the element or each element is formed as described. SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a noise attenuation panel comprising a first cellular component part which has a front face and a rear face and which has wall portions which extend across the first cellular component part from the front face to the rear face and which provide bounding surfaces for an array of cells, a second cellular component part which has a front face and a rear face and which is in the form of an open-celled structure, a backing component part which is secured to or adjoins the rear face of one of the cellular component parts, the front face of which is secured to or adjoins the rear face of the other cellular component part and a facing component part which is secured to or adjoins the front face of the other cellular component part. By "open-celled structure" is meant a cellular structure having a multiplicity of intercommunicating cells obtained by aggregation of particulate material or by the displacement of material by a dispersion or like technique from a body of material in liquid phase followed by a solidifying step. In one embodiment of the invention hereinafter to be described, the wall portions of the first cellular component part provide bounding surfaces for a multiplicity of open ended juxtaposed cells which terminate in open ends at the front and rear faces of the first cellular component part. The wall portions of the first cellular component part may be made from an impermeable material which may be a non-porous impermeable thermoplastics material. Alternatively, the wall portions of the first cellular component part may be made of a porous permeable thermoplastics material. In an embodiment of the invention hereinafter to be described the second cellular component part is made of a porous permeable thermoplastics material. Preferably, the porous permeable thermoplastics material is produced by powder sintering a thermoplastics material. The second cellular component part may also take the form of an open-celled plastics foam. In one of the embodiments of the invention hereinafter to be described the backing component part adjoins the rear face of the second cellular component part, the front face of which adjoins the rear face of the first cellular component part and the facing component part adjoins the front face of the first cellular component part. In another of the embodiments of the invention hereinafter to be described, the backing component part adjoins the rear face of the first cellular component part, the front face of which adjoins the rear face of the second cellular component part and the facing component part adjoins the front face of the second cellular component part. Adjoining component parts may be secured together by an adhesive material. Alternatively, two or more adjoining component parts may be made of compatible bonding thermoplastics materials and bonded together without the use of an adhesive material. In an embodiment of the invention hereinafter to be described the facing component part comprises or includes an outer facing sheet made of a porous permeable thermoplastics material. Preferably, the porous permeable thermoplastics material is produced by powder sintering a thermoplastics material. The facing component part may further include an inner facing sheet made from an open square weave fabric providing apertures therein constituted by the openings between adjacent warp and weft threads of the fabric. In an alternative embodiment of the invention the facing component part comprises an outer facing sheet which is made from an open square weave fabric providing apertures constituted by the openings between adjacent warp and weft threads of the fabric. Where an open square weave fabric is used it may be so woven as to produce a proportion of open aperture area relative to the total surface area of the sheet of 30% or substantially 30%. In the embodiments of the invention hereinafter to be described, the backing component part is imperforate and made of a non-porous impermeable material. The thermoplastics material used for the various component parts as hereinbefore specified may be polyether ether ketone. Alternatively, the thermoplastics material is polyether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide, thermoplastic polyimide, polyether-imide, polyurethane or polyethylene. According to a second aspect of the present invention, there is provided an aero engine having a surface subjected to the passage across it of gaseous flow and a noise attenuation panel according to the first aspect of the invention so positioned that its front face forms the surface or part of the surface subjected to passage of the gaseous flow across it. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described with reference to the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and in which: FIG. 1 is a schematic isometric view from above of a noise attenuation panel according to a first embodiment of the invention; FIG. 2 is a schematic cross section of an end region of the panel shown in FIG. 1, secured to a supporting channel member; FIGS. 3, 4, 5 and 6 are schematic cross sections of noise attenuation panels according to four further embodiments of the invention, and FIG. 7 is a schematic cross-section of an aero engine embodying noise attenuation panels according to the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, the noise attenuation panel 10 comprises a backing sheet 11, cellular elements 121 and 122 and a facing sheet 14. The upper cellular element 121 comprises a multiplicity of open-ended juxtaposed cells 15 of hexagonal cross section which form a honeycomb configuration and the lower cellular element 122 is made from a porous permeable thermoplastics material produced by powder sintering the thermoplastics material or is in the form of an open-celled plastics foam. The backing sheet 11 is unperforated and made from an impermeable sheet material and, as shown in FIG. 2, is secured by an epoxy resin adhesive E1 to the lower face of the cellular element 122. The facing sheet 14 is, as shown in FIG. 2, secured to the upper face of the cellular element 121 by means of an epoxy resin adhesive E2. The lower face of the cellular element 121 is secured to the upper face of the cellular element 122 by an epoxy resin adhesive E3. The epoxy adhesives E1, E2 and E3 may for example be obtained from Ciba-Geigy Plastics & Additives Company Limited of Cambridge, England. Adhesives and resins need not however be epoxy resin adhesives, but could for example be a phenolic, polyimide or thermoplastics resin. The facing sheet 14 comprises a sheet of a porous permeable thermoplastics material produced by powder sintering the thermoplastic. Examples of suitable thermoplastics materials include polyether ketone, polyether ether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide, thermoplastic polyimide, polyether imide, polyurethane and polyethylene. The walls of the cells of the cellular element 121 are made from a non-porous impermeable sheet of any of the following materials: (i) A thermoplastic such as polyether ether ketone. (ii) A polyester fabric/phenolic resin. (iii) A fibreglass/phenolic resin. (iv) A NOMEX/phenolic resin (NOMEX being a registered trade mark for an aramid fibre paper impregnated with various resins to produce a structural material). By "aramid" is meant an aromatic polyamide polymer. (v) An aluminium alloy. The walls of the cellular element 121 may alternatively be made of a porous thermoplastics material and in particular from any of the materials proposed for the facing sheet 14. The cellular element 122 may be manufactured from any suitable thermoplastics material. Examples of suitable thermoplastics materials include polyether ketone, polyether ether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide and thermoplastic polyimide, polyether-imide, polyurethane and polyethylene. The backing sheet 11 is imperforate and made of a non-porous impermeable material and may be made of any of the following materials: (i) A carbon/thermoplastic composite where for example the thermoplastic is polyether ether ketone, the material being automatically tape wound or hand laid. (ii) A carbon/epoxy resin. (iii) An aluminium alloy. The panel 10 is of arcuate form, possibly of double curvature, and is embodied as a structural part of a duct of a nose cowl of a turbofan aero engine, the panel 10 being one of several arcuate panels disposed just upstream of the fan of the engine. It is, of course, of vital importance that the panel does not deteriorate in use and, in particular, that no part of it becomes detached from its supporting structure. The structure will usually include supporting channel members of which only one member 17 is shown in FIG. 2. The panel 10 is secured to the member 17 by bonding the facing sheet 14 to an outer face of a flange 18 of the channel member 17 using carbon to carbon bond 19 and by bonding the backing sheet 11 to the outer face of a flange 20 of the channel member 17 using a carbon to carbon bond 21. The gap between the panel 10 and the base 22 of the channel member 17 may be sealed or closed by use of a mastic 23. A panel having a facing sheet 14 made of a porous thermoplastics material as described with reference to FIGS. 1 and 2 has been found to give rise to several advantages over the panels of the prior proposals, including the following: (1) The cellular structure of the facing sheet when produced by the powder sintering technique can be made to meet permeability requirements over a wide range. The cellular structure may be made permeable to gaseous flow over a wide range of tightly controlled flow and resistance requirements which will be engine dependent and non permeable to a wide range of liquids and solid contaminants. (2) The cellular structure of the facing sheet when produced by the powder sintering technique provides a highly complex interference flow path as a result of which the noise attenuation properties are greatly enhanced over other forms of perforate and porous material. (3) The very smooth surface of the facing sheet when produced by the powder sintering technique has substantial acoustic/air flow advantages over other perforate and porous forms. There is a lower flow resistance to high speed air flow, and therefore the overall aero engine power plant efficiency is improved over that obtained using the previously proposed panels; (4) the sound attenuation is greater and covers a wider frequency range than that of the previously proposed panels; (5) the thermoplastic component parts do not have the problem of metal galvanic corrosion; (6) the panel is lighter than the previously proposed panels; (7) there is an improved "blade-off" energy absorption compared with the previously proposed structures; and (8) there is an improved appearance. In addition, improved noise attenuation is achieved by using the combination of cellular elements 121 and 122 described with reference to FIGS. 1 and 2 or the combination now to be described with reference to any of FIGS. 3 to 6. Referring now to FIG. 3, a second embodiment of the invention is illustrated in which a panel 110 comprises a backing sheet 11, cellular elements 121 and 122 and a facing sheet 14. The backing sheet 11, the two cellular elements 121 and 122 and the facing sheet 14 take the same form as the corresponding elements of the panel 10 illustrated in FIGS. 1 and 2 and are joined together in the same manner by an adhesive E1 which secures the backing sheet 11 to the cellular element 121, an adhesive E2 which secures the facing sheet 14 to the upper face of the cellular element 122 and an adhesive E3 which secures the upper face of the element 121 to the lower face of the element 122. Preferably, the facing sheet 14 is, as in the panel 10 of FIGS. 1 and 2, made of a porous permeable thermoplastics material produced by powder sintering a thermoplastics material and the cellular element 122 is also preferably made of a thermoplastics material and may be formed in the same manner as the cellular element 122 of FIGS. 1 and 2. Referring now to FIG. 4 a further embodiment of the invention is illustrated in which a panel 210 takes the same form as the panel 110 in FIG. 3, except insofar as (i) the adhesive E2 is omitted, (ii) the facing sheet 14 and the cellular element 122 are made from compatible bonding thermoplastics materials and (iii) the facing sheet 14 is bonded direct to the upper face of the cellular element 122 during manufacture of the panel. In yet a further embodiment of the invention illustrated in FIG. 5, a panel 310 is provided which takes the same form as the panel 110 in FIG. 3 except insofar as the porous permeable thermoplastics facing sheet 14 is replaced by a facing sheet 13 which is secured to the upper face of the cellular element 122 using an adhesive E2 and which is made from an open square weave fabric formed from a carbon fibre/resin matrix composite material, the weave being such as to provide apertures constituted by the openings between adjacent warp and weft threads of the fabric. The fabric is preferably so woven as to produce a proportion of open aperture area relative to the total surface area of the sheet around 30%. In other respects, the panel 310 takes the same form as the panel 110 in FIG. 3 and is constructed in the same manner. In yet further embodiment of the invention illustrated in FIG. 6, a panel 410 is provided, which takes the same form and is constructed in the same manner as the panel 110 in FIG. 3, except insofar as the facing sheet 14 constitutes an outer facing sheet which extends over an inner facing sheet 13 of the same form as that provided in the panel 310 illustrated in FIG. 5. The facing sheet 14 is made of a porous permeable thermoplastics material produced by a powder sintering process and is bonded during manufacture to the inner facing sheet 13 which is in turn secured by adhesive E2 to the upper cellular element 122. Referring now to FIG. 7, an aero engine 25 is schematically illustrated and includes a turbofan power unit 26 mounted within a nacelle 27 suspended from a pylon 32. The nacelle 27 includes a nose cowl 28 having an outer wall 29 and an inner wall 30. The inner wall 30 is in part formed by noise attenuation panels P which may take the form of panels 10, 110, 210, 310 or 410 as described and illustrated with reference to FIGS. 1 to 6. The panels P are arranged to form part of the inner wall of the nose cowl 28 and serve to reduce noise created by the high speed flow of air passing through the duct 31 and into the power unit 26, as well as to reduce noise generated by the fan blades of the unit 26. It is to be emphasised that the panels in FIG. 7 are not employed to reduce air noise by a reduction of the air speed by passage of the air through the panels, but by contrast acoustic attenuation is achieved without affecting the speed of the air which generates the noise, that is to say, the air does not pass through the noise attenuation panels P. In the aero engine mounting arrangement illustrated in FIG. 7, the power unit is carried by the wing mounted pylon 32. It will however be appreciated that the noise attenuation panels according to the present invention may be equally well be employed for reducing noise in other aero engines installations.
A noise attenuation panel 10 for an aero engine environment comprises a first cellular component part 121 which has wall portions which extend from the front face to the rear face and which provide bounding surfaces for an array of cells 15 and a second cellular component part 122 in the form of an open-celled structure having a multiplicity of the intercommunicating cells obtained by aggregation of particulate material or by the displacement of material by a dispersion or like technique. A backing component part 11 is secured to the rear face of the second cellular component part 121, the front face of which is secured to the rear face of the first cellular component part and a facing component part 14 is secured to the front face of the first cellular component part. In an alternative form, the positions of the cellular component parts 121, 122 are interchanged.
Provide a concise summary of the essential information conveyed in the context.
[ "FIELD OF THE INVENTION The present invention relates to noise attenuation panels and is particularly, although not exclusively, concerned with noise attenuation panels for use in the attenuation of noise in aero engines.", "DESCRIPTION OF THE BACKGROUND ART In patent application publication GB-A- 2223448 there is disclosed a noise attenuation panel having a backing component part, a facing component part and a cellular component part having a multiplicity of open-ended juxtaposed cells, the backing component part extending across the ends of the cells of the cellular component part at the rear thereof and the facing component part extending across the ends of the cells of the cellular component part at the front thereof.", "In addition, the facing component part comprises or includes an outer facing sheet which is made of a porous permeable thermoplastics material.", "Preferably, the porous permeable thermoplastics material is produced by powder sintering of a thermoplastics materials.", "In one embodiment of the invention described in GB-A-2223448, the cellular component part comprises a single cellular element having wall portions which extend across the element from the front face thereof to the rear face thereof and which provide bounding surfaces for an array of open-ended juxtaposed cells.", "In another embodiment of the invention described in GB-A-2223448, the cellular component part is sub-divided into a front cellular element and a rear cellular element positioned to the rear of the front cellular element with a septum element extending between the two cellular elements.", "Each cellular element has wall portions which extend across the element from the front face thereof to the rear face thereof and which provide bounding surfaces for an array of open-ended juxtaposed cells.", "While the panel disclosed in GB-A-2223448 has been found to be successful for use in aero engine environments, drawbacks may be found in using a cellular component part formed as a single cellular element or as two cellular elements in which the element or each element is formed as described.", "SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a noise attenuation panel comprising a first cellular component part which has a front face and a rear face and which has wall portions which extend across the first cellular component part from the front face to the rear face and which provide bounding surfaces for an array of cells, a second cellular component part which has a front face and a rear face and which is in the form of an open-celled structure, a backing component part which is secured to or adjoins the rear face of one of the cellular component parts, the front face of which is secured to or adjoins the rear face of the other cellular component part and a facing component part which is secured to or adjoins the front face of the other cellular component part.", "By "open-celled structure"", "is meant a cellular structure having a multiplicity of intercommunicating cells obtained by aggregation of particulate material or by the displacement of material by a dispersion or like technique from a body of material in liquid phase followed by a solidifying step.", "In one embodiment of the invention hereinafter to be described, the wall portions of the first cellular component part provide bounding surfaces for a multiplicity of open ended juxtaposed cells which terminate in open ends at the front and rear faces of the first cellular component part.", "The wall portions of the first cellular component part may be made from an impermeable material which may be a non-porous impermeable thermoplastics material.", "Alternatively, the wall portions of the first cellular component part may be made of a porous permeable thermoplastics material.", "In an embodiment of the invention hereinafter to be described the second cellular component part is made of a porous permeable thermoplastics material.", "Preferably, the porous permeable thermoplastics material is produced by powder sintering a thermoplastics material.", "The second cellular component part may also take the form of an open-celled plastics foam.", "In one of the embodiments of the invention hereinafter to be described the backing component part adjoins the rear face of the second cellular component part, the front face of which adjoins the rear face of the first cellular component part and the facing component part adjoins the front face of the first cellular component part.", "In another of the embodiments of the invention hereinafter to be described, the backing component part adjoins the rear face of the first cellular component part, the front face of which adjoins the rear face of the second cellular component part and the facing component part adjoins the front face of the second cellular component part.", "Adjoining component parts may be secured together by an adhesive material.", "Alternatively, two or more adjoining component parts may be made of compatible bonding thermoplastics materials and bonded together without the use of an adhesive material.", "In an embodiment of the invention hereinafter to be described the facing component part comprises or includes an outer facing sheet made of a porous permeable thermoplastics material.", "Preferably, the porous permeable thermoplastics material is produced by powder sintering a thermoplastics material.", "The facing component part may further include an inner facing sheet made from an open square weave fabric providing apertures therein constituted by the openings between adjacent warp and weft threads of the fabric.", "In an alternative embodiment of the invention the facing component part comprises an outer facing sheet which is made from an open square weave fabric providing apertures constituted by the openings between adjacent warp and weft threads of the fabric.", "Where an open square weave fabric is used it may be so woven as to produce a proportion of open aperture area relative to the total surface area of the sheet of 30% or substantially 30%.", "In the embodiments of the invention hereinafter to be described, the backing component part is imperforate and made of a non-porous impermeable material.", "The thermoplastics material used for the various component parts as hereinbefore specified may be polyether ether ketone.", "Alternatively, the thermoplastics material is polyether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide, thermoplastic polyimide, polyether-imide, polyurethane or polyethylene.", "According to a second aspect of the present invention, there is provided an aero engine having a surface subjected to the passage across it of gaseous flow and a noise attenuation panel according to the first aspect of the invention so positioned that its front face forms the surface or part of the surface subjected to passage of the gaseous flow across it.", "Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter.", "However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.", "BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described with reference to the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and in which: FIG. 1 is a schematic isometric view from above of a noise attenuation panel according to a first embodiment of the invention;", "FIG. 2 is a schematic cross section of an end region of the panel shown in FIG. 1, secured to a supporting channel member;", "FIGS. 3, 4, 5 and 6 are schematic cross sections of noise attenuation panels according to four further embodiments of the invention, and FIG. 7 is a schematic cross-section of an aero engine embodying noise attenuation panels according to the invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, the noise attenuation panel 10 comprises a backing sheet 11, cellular elements 121 and 122 and a facing sheet 14.", "The upper cellular element 121 comprises a multiplicity of open-ended juxtaposed cells 15 of hexagonal cross section which form a honeycomb configuration and the lower cellular element 122 is made from a porous permeable thermoplastics material produced by powder sintering the thermoplastics material or is in the form of an open-celled plastics foam.", "The backing sheet 11 is unperforated and made from an impermeable sheet material and, as shown in FIG. 2, is secured by an epoxy resin adhesive E1 to the lower face of the cellular element 122.", "The facing sheet 14 is, as shown in FIG. 2, secured to the upper face of the cellular element 121 by means of an epoxy resin adhesive E2.", "The lower face of the cellular element 121 is secured to the upper face of the cellular element 122 by an epoxy resin adhesive E3.", "The epoxy adhesives E1, E2 and E3 may for example be obtained from Ciba-Geigy Plastics &", "Additives Company Limited of Cambridge, England.", "Adhesives and resins need not however be epoxy resin adhesives, but could for example be a phenolic, polyimide or thermoplastics resin.", "The facing sheet 14 comprises a sheet of a porous permeable thermoplastics material produced by powder sintering the thermoplastic.", "Examples of suitable thermoplastics materials include polyether ketone, polyether ether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide, thermoplastic polyimide, polyether imide, polyurethane and polyethylene.", "The walls of the cells of the cellular element 121 are made from a non-porous impermeable sheet of any of the following materials: (i) A thermoplastic such as polyether ether ketone.", "(ii) A polyester fabric/phenolic resin.", "(iii) A fibreglass/phenolic resin.", "(iv) A NOMEX/phenolic resin (NOMEX being a registered trade mark for an aramid fibre paper impregnated with various resins to produce a structural material).", "By "aramid"", "is meant an aromatic polyamide polymer.", "(v) An aluminium alloy.", "The walls of the cellular element 121 may alternatively be made of a porous thermoplastics material and in particular from any of the materials proposed for the facing sheet 14.", "The cellular element 122 may be manufactured from any suitable thermoplastics material.", "Examples of suitable thermoplastics materials include polyether ketone, polyether ether ketone, polyaromatic ketone, polyphenylene sulphide, polyamide-imide and thermoplastic polyimide, polyether-imide, polyurethane and polyethylene.", "The backing sheet 11 is imperforate and made of a non-porous impermeable material and may be made of any of the following materials: (i) A carbon/thermoplastic composite where for example the thermoplastic is polyether ether ketone, the material being automatically tape wound or hand laid.", "(ii) A carbon/epoxy resin.", "(iii) An aluminium alloy.", "The panel 10 is of arcuate form, possibly of double curvature, and is embodied as a structural part of a duct of a nose cowl of a turbofan aero engine, the panel 10 being one of several arcuate panels disposed just upstream of the fan of the engine.", "It is, of course, of vital importance that the panel does not deteriorate in use and, in particular, that no part of it becomes detached from its supporting structure.", "The structure will usually include supporting channel members of which only one member 17 is shown in FIG. 2. The panel 10 is secured to the member 17 by bonding the facing sheet 14 to an outer face of a flange 18 of the channel member 17 using carbon to carbon bond 19 and by bonding the backing sheet 11 to the outer face of a flange 20 of the channel member 17 using a carbon to carbon bond 21.", "The gap between the panel 10 and the base 22 of the channel member 17 may be sealed or closed by use of a mastic 23.", "A panel having a facing sheet 14 made of a porous thermoplastics material as described with reference to FIGS. 1 and 2 has been found to give rise to several advantages over the panels of the prior proposals, including the following: (1) The cellular structure of the facing sheet when produced by the powder sintering technique can be made to meet permeability requirements over a wide range.", "The cellular structure may be made permeable to gaseous flow over a wide range of tightly controlled flow and resistance requirements which will be engine dependent and non permeable to a wide range of liquids and solid contaminants.", "(2) The cellular structure of the facing sheet when produced by the powder sintering technique provides a highly complex interference flow path as a result of which the noise attenuation properties are greatly enhanced over other forms of perforate and porous material.", "(3) The very smooth surface of the facing sheet when produced by the powder sintering technique has substantial acoustic/air flow advantages over other perforate and porous forms.", "There is a lower flow resistance to high speed air flow, and therefore the overall aero engine power plant efficiency is improved over that obtained using the previously proposed panels;", "(4) the sound attenuation is greater and covers a wider frequency range than that of the previously proposed panels;", "(5) the thermoplastic component parts do not have the problem of metal galvanic corrosion;", "(6) the panel is lighter than the previously proposed panels;", "(7) there is an improved "blade-off"", "energy absorption compared with the previously proposed structures;", "and (8) there is an improved appearance.", "In addition, improved noise attenuation is achieved by using the combination of cellular elements 121 and 122 described with reference to FIGS. 1 and 2 or the combination now to be described with reference to any of FIGS. 3 to 6.", "Referring now to FIG. 3, a second embodiment of the invention is illustrated in which a panel 110 comprises a backing sheet 11, cellular elements 121 and 122 and a facing sheet 14.", "The backing sheet 11, the two cellular elements 121 and 122 and the facing sheet 14 take the same form as the corresponding elements of the panel 10 illustrated in FIGS. 1 and 2 and are joined together in the same manner by an adhesive E1 which secures the backing sheet 11 to the cellular element 121, an adhesive E2 which secures the facing sheet 14 to the upper face of the cellular element 122 and an adhesive E3 which secures the upper face of the element 121 to the lower face of the element 122.", "Preferably, the facing sheet 14 is, as in the panel 10 of FIGS. 1 and 2, made of a porous permeable thermoplastics material produced by powder sintering a thermoplastics material and the cellular element 122 is also preferably made of a thermoplastics material and may be formed in the same manner as the cellular element 122 of FIGS. 1 and 2.", "Referring now to FIG. 4 a further embodiment of the invention is illustrated in which a panel 210 takes the same form as the panel 110 in FIG. 3, except insofar as (i) the adhesive E2 is omitted, (ii) the facing sheet 14 and the cellular element 122 are made from compatible bonding thermoplastics materials and (iii) the facing sheet 14 is bonded direct to the upper face of the cellular element 122 during manufacture of the panel.", "In yet a further embodiment of the invention illustrated in FIG. 5, a panel 310 is provided which takes the same form as the panel 110 in FIG. 3 except insofar as the porous permeable thermoplastics facing sheet 14 is replaced by a facing sheet 13 which is secured to the upper face of the cellular element 122 using an adhesive E2 and which is made from an open square weave fabric formed from a carbon fibre/resin matrix composite material, the weave being such as to provide apertures constituted by the openings between adjacent warp and weft threads of the fabric.", "The fabric is preferably so woven as to produce a proportion of open aperture area relative to the total surface area of the sheet around 30%.", "In other respects, the panel 310 takes the same form as the panel 110 in FIG. 3 and is constructed in the same manner.", "In yet further embodiment of the invention illustrated in FIG. 6, a panel 410 is provided, which takes the same form and is constructed in the same manner as the panel 110 in FIG. 3, except insofar as the facing sheet 14 constitutes an outer facing sheet which extends over an inner facing sheet 13 of the same form as that provided in the panel 310 illustrated in FIG. 5. The facing sheet 14 is made of a porous permeable thermoplastics material produced by a powder sintering process and is bonded during manufacture to the inner facing sheet 13 which is in turn secured by adhesive E2 to the upper cellular element 122.", "Referring now to FIG. 7, an aero engine 25 is schematically illustrated and includes a turbofan power unit 26 mounted within a nacelle 27 suspended from a pylon 32.", "The nacelle 27 includes a nose cowl 28 having an outer wall 29 and an inner wall 30.", "The inner wall 30 is in part formed by noise attenuation panels P which may take the form of panels 10, 110, 210, 310 or 410 as described and illustrated with reference to FIGS. 1 to 6.", "The panels P are arranged to form part of the inner wall of the nose cowl 28 and serve to reduce noise created by the high speed flow of air passing through the duct 31 and into the power unit 26, as well as to reduce noise generated by the fan blades of the unit 26.", "It is to be emphasised that the panels in FIG. 7 are not employed to reduce air noise by a reduction of the air speed by passage of the air through the panels, but by contrast acoustic attenuation is achieved without affecting the speed of the air which generates the noise, that is to say, the air does not pass through the noise attenuation panels P. In the aero engine mounting arrangement illustrated in FIG. 7, the power unit is carried by the wing mounted pylon 32.", "It will however be appreciated that the noise attenuation panels according to the present invention may be equally well be employed for reducing noise in other aero engines installations." ]
The present invention relates to hydrogen peroxide solutions and more particularly to a process for its stabilisation. In a further aspect the present invention also relates to a stabiliser system for aqueous hydrogen peroxide solutions that are intended for use in metal surface treatments. BACKGROUND OF THE INVENTION One of the many uses for hydrogen peroxide solutions, and especially aqueous acidic hydrogen peroxide solutions, comprises the treatment of metal surfaces so as to alter their appearance and to impart chemically to the surface a desired sheen or polish. This is often referred to simply as pickling or polishing. Conventionally, solutions for that use contain one or more strong acids, which, is normally a mineral acid, as well as the hydrogen peroxide. In the course of the metal surface treatment, there is a tendency for the solution to dissolve metal or impurities from the metal surface and to strip away particulate particles that had adhered to the metal surface before the treatment commenced. The metals that are pickled or polished usually comprise or contain at least a proportion of transition metals, such as iron or copper, which catalyse the wasteful decomposition of hydrogen peroxide in aqueous solution into oxygen and water. In view of its decomposition in situ, hydrogen peroxide often represents the major consumable cost in a pickling or polishing process. In consequence, the industry continues to seek ever more effective ways of reducing the rate and/or extent of the decomposition. In many instances, it has been sought by introducing into solution one or more substances that are often called stabilisers, which interact with the metal ions and/or metal surface and/or the hydrogen peroxide itself in such a way as to reduce the rate or extent or modify the manner of the interactions between the metal ions and hydrogen peroxide causing decomposition. There have been many different chemical types of stabilisers proposed or employed. The literature directed to peroxide stabilisation during metal surface treatment processes includes many organic compounds as stabilisers such as a range of organic acids or unsaturated aliphatic acids in U.S. Pat. No. 3,537,895 by L. E. Lancy, aromatic alcohols or unsaturated aliphatic alcohols in U.S. Pat. No. 3,869,401 by R. E. Ernst, saturated alcohols in U.S. Pat. No. 3,556,883 by A. Naito et al, amines, amides and imines in U.S. Pat. No. 3,756,957 by S. Shiga, aryl sulphonic or sulphamic acids or related compounds in U.S. Pat. No. 3,801,512 by J. C. Solenberger et al and solid poorly soluble stabilisers like hydroxybenzoic acid in U.S. Pat. No. 4,770,808 by C. F. McDonogh et al. Many other stabilisers have been suggested for peroxide solutions including substances that chelate the metal ions or precipitate them out of solution, for example in U.S. Pat. No. 4,059,678 to D. C. Winkley. The literature also includes references to inorganic substances, such as phosphoric acid in U.S. Pat. No. 3,373,113 to Achenback. Accordingly there is a wide pool of stabilisers from which the user can select. Despite the foregoing, the present inventors found that there remains a significant problem of stabilising hydrogen peroxide during the metal surface treatment of steel with aqueous sulphuric acid solutions of hydrogen peroxide. This is because the greater part of the literature was directed to the treatment of copper surfaces and the authors extrapolated to the treatment of other metals without adequate experimental support. To some extent, this is demonstrated in U.S. Pat. No. 3,407,141 to R. S. Banush et al, which seeks to etch copper with acidic hydrogen peroxide solutions of long storage life that contain certain urea and aromatic acid compounds. The specification suggests that the treatment can be applied to certain other metals but also that the solutions are less effective on certain other metals such as . . . stainless steel . . . . Since the patent disclosed results solely with copper, comments regarding other metals may be regarded simply as speculation. In the course of the present research to identify, if possible, a suitable stabiliser system for acidic hydrogen peroxide solutions which are severely contaminated with dissolved iron, resulting for example from the surface treatment of steels, a large number of comparative stability trials were conducted. Each trial employed a stock solution containing 180 g/l sulphuric acid and 50 g/l hydrogen peroxide and 1% w/w "stabiliser" which was contaminated with 25 g/l dissolved iron from ferric sulphate, and stored at 30° C. or 50° C. Many of the substances tested fell within the classes of stabilisers identified in the above-mentioned patent specifications. The trials indicated that many substances which had been described in the past as stabilisers for hydrogen peroxide in solutions containing only small amounts of catalytic ions, were unable to prevent rapid decomposition if substantial iron contamination was present, including chelating stabilisers like ethylenediaminetetraacetic acid, dipicolinic acid, nitrilotriacetic acid and ethylidene-1-hydroxy-1,1-diphosphonic acid. Moreover, it was found that some substances that acted quite well as stabilisers when employed separately, acted no better or even less well when employed in cogitation under the conditions of the trial. Other combinations of substances demonstrated strictly additive stabiliser properties. Accordingly, the trials demonstrated that a disclosure in a published patent specification that a substance had stabiliser properties towards hydrogen peroxide under much less extreme conditions or in the presence of copper as the main catalytic contaminant was no guarantee that it was capable of performing adequately in the presence of a substantial concentration of dissolved iron. The trials also demonstrated that there was no guarantee that substances that had been suggested individually as stabilisers, possibly guarding against other sources of decomposition, would combine together even additively when employed in combination. SUMMARY OF THE INVENTION It is an object of the present invention to locate a combination of substances which could stabilise hydrogen peroxide effectively in aqueous sulphuric acid solutions that are employed in the surface treatment of steel and therefore become contaminated with significant concentrations of iron. According to a first aspect of the present invention there is provided a process for stabilising an aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid which are suitable for treating the surface of steel and like alloys characterised in that there is introduced into the solution an effective amount, in combination of hydrofluoric acid, hydroxybenzoic acid and an N-alkoxyphenyl-acetamide. According to a related aspect, there is provided a stabilised aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid and an effective amount in combination of hydrofluoric acid, hydroxybenzoic acid and an N-alkoxyphenyl-acetamide. According to a further and related aspect of the present invention there is provided a process for the surface treatment of steel or a like alloy in which the latter is contacted with an aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid characterised in that it contains an effective amount in combination of hydrofluoric acid, hydroxybenzoic acid and an N-(alkoxyphenyl)-acetamide. In the context of the present invention, the stabiliser combination comprises hydrofluoric acid, an aromatic acid and an aromatic amide. The hydroxybenzoic acid is particularly preferably p-hydroxybenzoic acid and the N-(alkanoxyphenyl)-acetamide, advantageously, contains a low molecular weight alkanoxy substituent and especially the compound is N-(4-ethoxy-phenyl)-acetamide. DESCRIPTION OF PREFERRED EMBODIMENTS Without being bound to any particular theory, the inventors believe that the components of the stabiliser system form a range of fluoride-containing complexes with iron and other ions that pass into solution during surface treatment of steels. The properties of these complexes, and in particular their interaction with hydrogen peroxide are believed to dictate the stability and hence extent of decomposition losses of hydrogen peroxide during the surface treatments. Furthermore, the presence of hydrofluoric acid is believed to provide the potential for the iron complexes to be significantly different from corresponding complexes in the absence of hydrofluoric acid and that this may explain to at least some extent why it is so difficult to apply teachings given for other solutions in the prior art and teachings on individual components in respect of the combination of the present invention. The solution preferably contains from 0.5 to 10% w/w hydrofluoric acid and advantageously from 1 to 6%. The concentrations of the aromatic acid and the aromatic amide in solution are each preferably at least 0.5 g/l and most preferably at or near saturation. Since they tend to be relatively poorly soluble, saturation can be attained by introduction of about 1 g/l up to a few g/l of each. The weight ratio of the hydroxy benzoic acid to the acetamide is preferably in the range of 25:1 to 1:5. In one preferred method of employing the invention stabiliser combination, advantage is taken of the physical properties of the two aromatic components, namely the acid and amide. In the preferred method, these two components are selected on the bases of their melting point and solubility. Specifically, it is preferable to select an acid and an amide which does not melt until a temperature significantly in excess of about 70° C. is attained and which are scarcely soluble in an aqueous acidic medium. Such compounds will naturally be solids in the normal range of operating temperatures for hydrogen peroxide-based steel surface treatments and can dissolve to form a dilute, but saturated solution. It is especially desirable to incorporate an excess amount of the aromatic acid and amide beyond that needed for a saturated solution so as to provide within the treatment bath a solid phase, a reservoir which can replenish the saturated solution as the compound is removed by the normal operation of the metal surface treatments, including in situ oxidation and by adhesion to the surface of the workpiece on separation from the bath. It will be recognised that both the above-named aromatic acid and aromatic amide demonstrate both such preferred characteristics, thereby rendering them especially attractive for this preferred method. Whilst it is conceivable to incorporate such solids in the metal surface treatment solution in powder or granular form, there is a distinct tendency for that form of solids to be lost by carry out from a surface treatment bath. Powders are not easy to observe, so that it can be difficult to know how much of the solids are still present and in the extreme case whether any is present at all. Accordingly, in a more preferred mode of operation, the two solid poorly soluble components of the stabiliser system are each employed in the form of a block containing either an individual component or a mixture of them. The block is much easier to detect than is the corresponding amount of powder or flakes, either visually or by a non-manual system. Accordingly, regulation of the solid stabilisers in the treatment bath can be accomplished without recourse to elaborate and expensive monitoring equipment, whilst still minimising the possibility that the bath would be left without the organic components of the stabiliser system. The term "block" is used in its normal dictionary meaning, as in U.S. Pat. No. 4,770,808, and covers a wide range of sizes. It typically has a weight of at least 30 g and up to a few kg weight, e.g. 10 kg. For many practical purposes, it weighs initially from 200 g to 5 kg, but will slowly be consumed during operation of the bath. The block is normally obtained by compression or binding of flakes, granules or powders into a tablet shape or in some other mould shape such as cube, cuboid polyhedron or cylinder, or by resolidification of a melt in such a mould or by extrusion of a rod or bar. Such techniques are well known in the field of tablet or block formation and accordingly need not be described in further detail herein. The hydrogen peroxide solution is often described as a dilute solution. It normally contains at least 1% w/w hydrogen peroxide and it is unusual for it to contain more than 10% w/w. For the treatment of steels, it is often convenient to select within the range of from 3 to 8% w/w hydrogen peroxide. During normal operation, peroxide is consumed, so that without corrective means, its concentration would gradually diminish. At the discretion of the user, he can seek to maintain a steady state by introducing peroxide gradually at a rate that matches its consumption, including decomposition, or he can permit the concentration to fluctuate by augmenting the peroxide concentration periodically. The metal treatment solution is most conveniently obtained by the dilution of a concentrated commercial hydrogen peroxide solution, typically containing from 35 to 70% w/w hydrogen peroxide and trace amounts, i.e. below about 0.1% of known storage stabilisers such as pyrophosphate and/or stannate and/or polyphosphonic acid compounds. The sulphuric acid concentration in the solution is normally not higher than 20% v/v and in many instances is conveniently selected in the region of 5 to 15% v/v. The solution can also include minor amounts of the customary additives in metal treatment solutions, such as up to about 2% w/w wetting agents. The processes using the stabilised hydrogen peroxide solutions of the present invention are normally carried out at a bath temperature of above ambient, and in many instances in the range of from 40° C. to 70° C. Higher temperatures of up to about 80° C. are less often encountered, but become more attractive as a result of the stabilisation of the hydrogen peroxide component in the bath. The residence period for the work-piece in the treatment bath is at the discretion of the user and naturally depends on the finish that it is desired to achieve. Residence periods are often selected in the range of from 30 seconds to 30 minutes, and normally from 1 to 5 minutes. The stabilised acidic hydrogen peroxide solutions are primarily intended for the pickling or polishing of steels, including mild steel and is of especial value for treating stainless steels. Steels suitable for treatment by the invention process and compositions can contain minor proportions of such metals as chromium, nickle, and manganese; i.e. the metals that are incorporated in corrosion-resistant or stainless steels. It will be recognised that the process and compositions according to the present invention can be employed instead of nitric acid-containing metal treatment compositions, thereby avoiding the problems of NOx emissions that accompany the use of nitric acid. Having described the invention in general terms, specific embodiments thereof will now be described in more detail by way of example only. EXAMPLE 1 AND COMPARISONS CA TO CC In this example and these comparisons, the effectiveness of the invention combination of stabiliser components is compared under the same conditions of high dissolved iron with stabiliser-free pickling solution and solution containing components of the combination. In each trial, a solution was prepared which contained 5% w/w hydrogen peroxide, 10% v/v sulphuric acid, and 1.8% w/w ferric iron, added as ferric sulphate and the stabiliser(s) listed in Table 1 below were then mixed into the solution. The solid stabilisers are referred to by their abbreviations; PHBA for p-hydroxybenzoic acid and NEPA for N-(4-ethoxy-phenyl)acetamide. Although the hydrofluoric acid was entirely miscible with the solution, the solid stabilisers did not dissolve completely, forming a saturated solution of the two compounds and leaving a residue of solid material. The solutions were then kept at 30° C. and the residual hydrogen peroxide content was measured at intervals by the standard potassium permanganate method. Table 1 below indicates the half life of the hydrogen peroxide in the solution, by which herein we mean the time taken for the measured hydrogen peroxide to fall to half its initial concentration. TABLE 1______________________________________ Half-life ofExample Stabiliser System g/l H.sub.2 O.sub.2Comp No HF PHBA NEPA hours______________________________________CA -- -- -- 2CB 40 -- -- 3CC -- 5 5 8Ex1 40 5 5 >300______________________________________ From Table 1, it can be seen that the effect of employing either the HF alone or the solids alone resulted in some improvement in peroxide stability, but their use in combination resulted in a very substantial improvement, well mn excess of a simple additive effect. This shows that the combination is particularly effective in the presence of substantial concentrations of iron in solution, as would arise from the surface treatment of steel and like alloys. EXAMPLES 2 TO 5 In these examples, Example 1 was repeated, but using respectively a total weight of PHBA and NEPA (wt ratio 1:1) of 5 g/l, 10 g/l, 15 g/l and 20 g/l, HF at 40 g/l, 12.5% by volume sulphuric acid (98% w/w), about 50 g/l hydrogen peroxide and 29 g/l iron introduced as ferric sulphate. Within the limits of experimental variation, all four amounts of stabilisers resulted in a similar and high proportion of hydrogen peroxide being retained, viz about 82% after 43 hours. This is consistent with PHBA and NEPA forming saturated solutions at all four stabiliser amounts tested. To the extent that any trend was apparent, the most efficatious amount was the smallest. EXAMPLES 6 TO 11 In these examples, a solution was prepared which contained 5% w/w hydrogen peroxide, 10% v/v sulphuric acid, 1.8% w/w ferric iron, added as ferric sulphate and 10 g/l of a mixture of PHBA and NEPA in the proportions by weight listed in Table 2. The solutions were stored at 50° C. in order to obtain the comparative results quickly, and residual hydrogen peroxide contents measured at intervals, as for Example 1. Table 2 indicates the percentage remaining after 24 hours. TABLE 2______________________________________Ex No Ratio of NEPA:PHBA % peroxide remaining______________________________________6 2.3:1 467 1:1 428 1:4 539 1:9 4310 1:24 4511 9:1 32______________________________________ From Table 2, it can be seen that the combination of HF plus NEPA plus PHBA remained a very effective stabiliser over a wide range of ratios of NEPA to PHBA, and especially in Examples 6 to 10 in which the amount of each of the two solid components was sufficient to ensure a saturated solution of each. EXAMPLE 12 In this example, Example 7 was repeated but employing a solution containing additionally chromium at a concentration of 5 g/l, introduced as chromic sulphate. Within the limits of experimental variations, the proportion of hydrogen peroxide remaining in solution after 24 hours storage at 50° C. was the same as in the absence of the chromium. This demonstrates that the stabiliser system is applicable for use in the surface treatment of stainless steels. In other comparative tests carried out with varying additions of chromium to an iron contaminated sulphuric acid/peroxide solution containing the invention stabiliser system, there was a tendency for the stabilisation to become somewhat impaired as the concentration of chromium was increased from 5 to 20 g/l.
It would be desirable to replace nitric acid based solutions for surface treating steels and like materials with a sulphuric acid based solution containing hydrogen peroxide, but such replacement solutions lose hydrogen peroxide rapidly through mainly iron-induced decomposition. A surface treatment solution that is based on sulphuric acid and hydrogen peroxide, but has improved stability, contains an effective amount in combination of hydrofluoric acid, are hydroxybenzoic acid and an N-alkoxyphenyl-acetamide. Preferably, the hydroxybenzoic acid is para-hydroxybenzoic acid and the N-alkoxyphenyl-acetamide is N-(4-ethoxyphenyl)-acetamide. It is preferable to employ a saturated solution of each of the two latter components, and this can achieved practically and simply by adding the solid components in the shape of a block or blocks which maintain the saturated solution over an extended period of time.
Concisely explain the essential features and purpose of the invention.
[ "The present invention relates to hydrogen peroxide solutions and more particularly to a process for its stabilisation.", "In a further aspect the present invention also relates to a stabiliser system for aqueous hydrogen peroxide solutions that are intended for use in metal surface treatments.", "BACKGROUND OF THE INVENTION One of the many uses for hydrogen peroxide solutions, and especially aqueous acidic hydrogen peroxide solutions, comprises the treatment of metal surfaces so as to alter their appearance and to impart chemically to the surface a desired sheen or polish.", "This is often referred to simply as pickling or polishing.", "Conventionally, solutions for that use contain one or more strong acids, which, is normally a mineral acid, as well as the hydrogen peroxide.", "In the course of the metal surface treatment, there is a tendency for the solution to dissolve metal or impurities from the metal surface and to strip away particulate particles that had adhered to the metal surface before the treatment commenced.", "The metals that are pickled or polished usually comprise or contain at least a proportion of transition metals, such as iron or copper, which catalyse the wasteful decomposition of hydrogen peroxide in aqueous solution into oxygen and water.", "In view of its decomposition in situ, hydrogen peroxide often represents the major consumable cost in a pickling or polishing process.", "In consequence, the industry continues to seek ever more effective ways of reducing the rate and/or extent of the decomposition.", "In many instances, it has been sought by introducing into solution one or more substances that are often called stabilisers, which interact with the metal ions and/or metal surface and/or the hydrogen peroxide itself in such a way as to reduce the rate or extent or modify the manner of the interactions between the metal ions and hydrogen peroxide causing decomposition.", "There have been many different chemical types of stabilisers proposed or employed.", "The literature directed to peroxide stabilisation during metal surface treatment processes includes many organic compounds as stabilisers such as a range of organic acids or unsaturated aliphatic acids in U.S. Pat. No. 3,537,895 by L. E. Lancy, aromatic alcohols or unsaturated aliphatic alcohols in U.S. Pat. No. 3,869,401 by R. E. Ernst, saturated alcohols in U.S. Pat. No. 3,556,883 by A. Naito et al, amines, amides and imines in U.S. Pat. No. 3,756,957 by S. Shiga, aryl sulphonic or sulphamic acids or related compounds in U.S. Pat. No. 3,801,512 by J. C. Solenberger et al and solid poorly soluble stabilisers like hydroxybenzoic acid in U.S. Pat. No. 4,770,808 by C. F. McDonogh et al.", "Many other stabilisers have been suggested for peroxide solutions including substances that chelate the metal ions or precipitate them out of solution, for example in U.S. Pat. No. 4,059,678 to D. C. Winkley.", "The literature also includes references to inorganic substances, such as phosphoric acid in U.S. Pat. No. 3,373,113 to Achenback.", "Accordingly there is a wide pool of stabilisers from which the user can select.", "Despite the foregoing, the present inventors found that there remains a significant problem of stabilising hydrogen peroxide during the metal surface treatment of steel with aqueous sulphuric acid solutions of hydrogen peroxide.", "This is because the greater part of the literature was directed to the treatment of copper surfaces and the authors extrapolated to the treatment of other metals without adequate experimental support.", "To some extent, this is demonstrated in U.S. Pat. No. 3,407,141 to R. S. Banush et al, which seeks to etch copper with acidic hydrogen peroxide solutions of long storage life that contain certain urea and aromatic acid compounds.", "The specification suggests that the treatment can be applied to certain other metals but also that the solutions are less effective on certain other metals such as .", "stainless steel .", "Since the patent disclosed results solely with copper, comments regarding other metals may be regarded simply as speculation.", "In the course of the present research to identify, if possible, a suitable stabiliser system for acidic hydrogen peroxide solutions which are severely contaminated with dissolved iron, resulting for example from the surface treatment of steels, a large number of comparative stability trials were conducted.", "Each trial employed a stock solution containing 180 g/l sulphuric acid and 50 g/l hydrogen peroxide and 1% w/w "stabiliser"", "which was contaminated with 25 g/l dissolved iron from ferric sulphate, and stored at 30° C. or 50° C. Many of the substances tested fell within the classes of stabilisers identified in the above-mentioned patent specifications.", "The trials indicated that many substances which had been described in the past as stabilisers for hydrogen peroxide in solutions containing only small amounts of catalytic ions, were unable to prevent rapid decomposition if substantial iron contamination was present, including chelating stabilisers like ethylenediaminetetraacetic acid, dipicolinic acid, nitrilotriacetic acid and ethylidene-1-hydroxy-1,1-diphosphonic acid.", "Moreover, it was found that some substances that acted quite well as stabilisers when employed separately, acted no better or even less well when employed in cogitation under the conditions of the trial.", "Other combinations of substances demonstrated strictly additive stabiliser properties.", "Accordingly, the trials demonstrated that a disclosure in a published patent specification that a substance had stabiliser properties towards hydrogen peroxide under much less extreme conditions or in the presence of copper as the main catalytic contaminant was no guarantee that it was capable of performing adequately in the presence of a substantial concentration of dissolved iron.", "The trials also demonstrated that there was no guarantee that substances that had been suggested individually as stabilisers, possibly guarding against other sources of decomposition, would combine together even additively when employed in combination.", "SUMMARY OF THE INVENTION It is an object of the present invention to locate a combination of substances which could stabilise hydrogen peroxide effectively in aqueous sulphuric acid solutions that are employed in the surface treatment of steel and therefore become contaminated with significant concentrations of iron.", "According to a first aspect of the present invention there is provided a process for stabilising an aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid which are suitable for treating the surface of steel and like alloys characterised in that there is introduced into the solution an effective amount, in combination of hydrofluoric acid, hydroxybenzoic acid and an N-alkoxyphenyl-acetamide.", "According to a related aspect, there is provided a stabilised aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid and an effective amount in combination of hydrofluoric acid, hydroxybenzoic acid and an N-alkoxyphenyl-acetamide.", "According to a further and related aspect of the present invention there is provided a process for the surface treatment of steel or a like alloy in which the latter is contacted with an aqueous solution of hydrogen peroxide containing at least 1% w/w sulphuric acid characterised in that it contains an effective amount in combination of hydrofluoric acid, hydroxybenzoic acid and an N-(alkoxyphenyl)-acetamide.", "In the context of the present invention, the stabiliser combination comprises hydrofluoric acid, an aromatic acid and an aromatic amide.", "The hydroxybenzoic acid is particularly preferably p-hydroxybenzoic acid and the N-(alkanoxyphenyl)-acetamide, advantageously, contains a low molecular weight alkanoxy substituent and especially the compound is N-(4-ethoxy-phenyl)-acetamide.", "DESCRIPTION OF PREFERRED EMBODIMENTS Without being bound to any particular theory, the inventors believe that the components of the stabiliser system form a range of fluoride-containing complexes with iron and other ions that pass into solution during surface treatment of steels.", "The properties of these complexes, and in particular their interaction with hydrogen peroxide are believed to dictate the stability and hence extent of decomposition losses of hydrogen peroxide during the surface treatments.", "Furthermore, the presence of hydrofluoric acid is believed to provide the potential for the iron complexes to be significantly different from corresponding complexes in the absence of hydrofluoric acid and that this may explain to at least some extent why it is so difficult to apply teachings given for other solutions in the prior art and teachings on individual components in respect of the combination of the present invention.", "The solution preferably contains from 0.5 to 10% w/w hydrofluoric acid and advantageously from 1 to 6%.", "The concentrations of the aromatic acid and the aromatic amide in solution are each preferably at least 0.5 g/l and most preferably at or near saturation.", "Since they tend to be relatively poorly soluble, saturation can be attained by introduction of about 1 g/l up to a few g/l of each.", "The weight ratio of the hydroxy benzoic acid to the acetamide is preferably in the range of 25:1 to 1:5.", "In one preferred method of employing the invention stabiliser combination, advantage is taken of the physical properties of the two aromatic components, namely the acid and amide.", "In the preferred method, these two components are selected on the bases of their melting point and solubility.", "Specifically, it is preferable to select an acid and an amide which does not melt until a temperature significantly in excess of about 70° C. is attained and which are scarcely soluble in an aqueous acidic medium.", "Such compounds will naturally be solids in the normal range of operating temperatures for hydrogen peroxide-based steel surface treatments and can dissolve to form a dilute, but saturated solution.", "It is especially desirable to incorporate an excess amount of the aromatic acid and amide beyond that needed for a saturated solution so as to provide within the treatment bath a solid phase, a reservoir which can replenish the saturated solution as the compound is removed by the normal operation of the metal surface treatments, including in situ oxidation and by adhesion to the surface of the workpiece on separation from the bath.", "It will be recognised that both the above-named aromatic acid and aromatic amide demonstrate both such preferred characteristics, thereby rendering them especially attractive for this preferred method.", "Whilst it is conceivable to incorporate such solids in the metal surface treatment solution in powder or granular form, there is a distinct tendency for that form of solids to be lost by carry out from a surface treatment bath.", "Powders are not easy to observe, so that it can be difficult to know how much of the solids are still present and in the extreme case whether any is present at all.", "Accordingly, in a more preferred mode of operation, the two solid poorly soluble components of the stabiliser system are each employed in the form of a block containing either an individual component or a mixture of them.", "The block is much easier to detect than is the corresponding amount of powder or flakes, either visually or by a non-manual system.", "Accordingly, regulation of the solid stabilisers in the treatment bath can be accomplished without recourse to elaborate and expensive monitoring equipment, whilst still minimising the possibility that the bath would be left without the organic components of the stabiliser system.", "The term "block"", "is used in its normal dictionary meaning, as in U.S. Pat. No. 4,770,808, and covers a wide range of sizes.", "It typically has a weight of at least 30 g and up to a few kg weight, e.g. 10 kg.", "For many practical purposes, it weighs initially from 200 g to 5 kg, but will slowly be consumed during operation of the bath.", "The block is normally obtained by compression or binding of flakes, granules or powders into a tablet shape or in some other mould shape such as cube, cuboid polyhedron or cylinder, or by resolidification of a melt in such a mould or by extrusion of a rod or bar.", "Such techniques are well known in the field of tablet or block formation and accordingly need not be described in further detail herein.", "The hydrogen peroxide solution is often described as a dilute solution.", "It normally contains at least 1% w/w hydrogen peroxide and it is unusual for it to contain more than 10% w/w.", "For the treatment of steels, it is often convenient to select within the range of from 3 to 8% w/w hydrogen peroxide.", "During normal operation, peroxide is consumed, so that without corrective means, its concentration would gradually diminish.", "At the discretion of the user, he can seek to maintain a steady state by introducing peroxide gradually at a rate that matches its consumption, including decomposition, or he can permit the concentration to fluctuate by augmenting the peroxide concentration periodically.", "The metal treatment solution is most conveniently obtained by the dilution of a concentrated commercial hydrogen peroxide solution, typically containing from 35 to 70% w/w hydrogen peroxide and trace amounts, i.e. below about 0.1% of known storage stabilisers such as pyrophosphate and/or stannate and/or polyphosphonic acid compounds.", "The sulphuric acid concentration in the solution is normally not higher than 20% v/v and in many instances is conveniently selected in the region of 5 to 15% v/v.", "The solution can also include minor amounts of the customary additives in metal treatment solutions, such as up to about 2% w/w wetting agents.", "The processes using the stabilised hydrogen peroxide solutions of the present invention are normally carried out at a bath temperature of above ambient, and in many instances in the range of from 40° C. to 70° C. Higher temperatures of up to about 80° C. are less often encountered, but become more attractive as a result of the stabilisation of the hydrogen peroxide component in the bath.", "The residence period for the work-piece in the treatment bath is at the discretion of the user and naturally depends on the finish that it is desired to achieve.", "Residence periods are often selected in the range of from 30 seconds to 30 minutes, and normally from 1 to 5 minutes.", "The stabilised acidic hydrogen peroxide solutions are primarily intended for the pickling or polishing of steels, including mild steel and is of especial value for treating stainless steels.", "Steels suitable for treatment by the invention process and compositions can contain minor proportions of such metals as chromium, nickle, and manganese;", "i.e. the metals that are incorporated in corrosion-resistant or stainless steels.", "It will be recognised that the process and compositions according to the present invention can be employed instead of nitric acid-containing metal treatment compositions, thereby avoiding the problems of NOx emissions that accompany the use of nitric acid.", "Having described the invention in general terms, specific embodiments thereof will now be described in more detail by way of example only.", "EXAMPLE 1 AND COMPARISONS CA TO CC In this example and these comparisons, the effectiveness of the invention combination of stabiliser components is compared under the same conditions of high dissolved iron with stabiliser-free pickling solution and solution containing components of the combination.", "In each trial, a solution was prepared which contained 5% w/w hydrogen peroxide, 10% v/v sulphuric acid, and 1.8% w/w ferric iron, added as ferric sulphate and the stabiliser(s) listed in Table 1 below were then mixed into the solution.", "The solid stabilisers are referred to by their abbreviations;", "PHBA for p-hydroxybenzoic acid and NEPA for N-(4-ethoxy-phenyl)acetamide.", "Although the hydrofluoric acid was entirely miscible with the solution, the solid stabilisers did not dissolve completely, forming a saturated solution of the two compounds and leaving a residue of solid material.", "The solutions were then kept at 30° C. and the residual hydrogen peroxide content was measured at intervals by the standard potassium permanganate method.", "Table 1 below indicates the half life of the hydrogen peroxide in the solution, by which herein we mean the time taken for the measured hydrogen peroxide to fall to half its initial concentration.", "TABLE 1______________________________________ Half-life ofExample Stabiliser System g/l H.sub[.", "].2 O.sub[.", "].2Comp No HF PHBA NEPA hours______________________________________CA -- -- -- 2CB 40 -- -- 3CC -- 5 5 8Ex1 40 5 5 >300______________________________________ From Table 1, it can be seen that the effect of employing either the HF alone or the solids alone resulted in some improvement in peroxide stability, but their use in combination resulted in a very substantial improvement, well mn excess of a simple additive effect.", "This shows that the combination is particularly effective in the presence of substantial concentrations of iron in solution, as would arise from the surface treatment of steel and like alloys.", "EXAMPLES 2 TO 5 In these examples, Example 1 was repeated, but using respectively a total weight of PHBA and NEPA (wt ratio 1:1) of 5 g/l, 10 g/l, 15 g/l and 20 g/l, HF at 40 g/l, 12.5% by volume sulphuric acid (98% w/w), about 50 g/l hydrogen peroxide and 29 g/l iron introduced as ferric sulphate.", "Within the limits of experimental variation, all four amounts of stabilisers resulted in a similar and high proportion of hydrogen peroxide being retained, viz about 82% after 43 hours.", "This is consistent with PHBA and NEPA forming saturated solutions at all four stabiliser amounts tested.", "To the extent that any trend was apparent, the most efficatious amount was the smallest.", "EXAMPLES 6 TO 11 In these examples, a solution was prepared which contained 5% w/w hydrogen peroxide, 10% v/v sulphuric acid, 1.8% w/w ferric iron, added as ferric sulphate and 10 g/l of a mixture of PHBA and NEPA in the proportions by weight listed in Table 2.", "The solutions were stored at 50° C. in order to obtain the comparative results quickly, and residual hydrogen peroxide contents measured at intervals, as for Example 1.", "Table 2 indicates the percentage remaining after 24 hours.", "TABLE 2______________________________________Ex No Ratio of NEPA:PHBA % peroxide remaining______________________________________6 2.3:1 467 1:1 428 1:4 539 1:9 4310 1:24 4511 9:1 32______________________________________ From Table 2, it can be seen that the combination of HF plus NEPA plus PHBA remained a very effective stabiliser over a wide range of ratios of NEPA to PHBA, and especially in Examples 6 to 10 in which the amount of each of the two solid components was sufficient to ensure a saturated solution of each.", "EXAMPLE 12 In this example, Example 7 was repeated but employing a solution containing additionally chromium at a concentration of 5 g/l, introduced as chromic sulphate.", "Within the limits of experimental variations, the proportion of hydrogen peroxide remaining in solution after 24 hours storage at 50° C. was the same as in the absence of the chromium.", "This demonstrates that the stabiliser system is applicable for use in the surface treatment of stainless steels.", "In other comparative tests carried out with varying additions of chromium to an iron contaminated sulphuric acid/peroxide solution containing the invention stabiliser system, there was a tendency for the stabilisation to become somewhat impaired as the concentration of chromium was increased from 5 to 20 g/l." ]
BACKGROUND OF THE INVENTION This invention relates to forms for use in casting of concrete walls and more particularly to forms used in the casting of stepped openings in walls. It is a common practice in the construction of concrete buildings to build concrete houses to cast the walls or wall sections as slabs in horizontal forms. After the concrete has cured, the wall is raised to vertical position, moved into position with other walls of the structure and joined thereto. It is also common practice to cast the wall sections with suitably located door and window openings. In many instances, the specifications for a wall section will include one or more window or door openings having a stepped configuration to provide a shoulder against which a door or window is to close, and, in many instances, the specifications are such that when the wall is cast in its horizontal form, the shoulder of the opening is facing downwardly. In such case the dimensions of the opening at the upper surface of the poured slab are less than that at the bottom of the slab. It is a relatively simple matter to design a form having a shape which will give the desired stepped configuration to the opening. However, the construction of such forms represents a significant cost factor. Since the form is larger at the bottom it cannot be removed from the cast slab simply by pulling it out. Removal while the slab is still in place is usually accompanied by partial or complete destruction of the form. As a result, a new form is usually required for each opening to be cast. This increases the cost and increases the chances that the form will not have the precise dimensions desired. The forms can be removed through the larger side of the opening after the slab has cured and has been raised from the casting pad. However, this necessitates a long delay before any possible reuse of the form. Window and door openings in the finished wall must also be provided with appropriate hardware so that windows and doors can be hung in the opening. Usually such hardware is installed after the walls are in place, which is a relatively expensive procedure since it requires that holes be drilled into the concrete or that nail guns be used. There have been attempts to secure the hardware to the forms so that the hardware will be cast as the concrete is poured. This has not been too satisfactory since it is difficult and time-consuming to attach the hardware to the form. Also, the hardware must be very carefully positioned on the form so that the cast-in-place hardware will properly mate with the hardware on the doors and windows to be later installed. It is the principal object of the present invention to provide a form for a stepped opening in a cast concrete wall which can be easily removed after the initial set of concrete and can be promptly reused for forming another opening. It is a further object of the present invention to provide a form for openings in cast concrete walls which enables hardware to be easily secured to the form and precisely positioned thereon so that such hardware can be cast into the opening as the concrete is poured. SUMMARY OF THE INVENTION The form of the present invention comprises a separate form member for each side of the opening, each form member having casting surfaces for forming the desired stepped configuration of the opening. The maximum length of each form member is less than the smallest length of the opening it is forming so that the form member can be removed therefrom. Special corner pieces are provided at each corner of the form to complete the casting surfaces and to permit translatory movement of the form members out from under the downwardly facing shoulder cast into the opening so that the form members can be removed. The form members of the present invention are also provided with means for precisely located hardware to be cast into the opening, and are provided with magnets for holding hardware to the form as the concrete is poured. Other objects and advantages will become apparent in the course of the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, forming a part of this application, and in which like parts are designated by like reference numerals throughout the same, FIG. 1 is a plan view of a casting pad with a wall and window form assembled thereon, the window form being constructed in accordance with the invention, FIG. 2 is a perspective view of a concrete wall cast from the forms of FIG. 1, FIG. 3 is a perspective view, partially exploded of the window form of FIG. 1, looking towards one corner thereof from outside of the form, FIG. 4 is a perspective view of the window form of FIG. 1, looking towards one corner thereof from the inside of the form, FIG. 5 is a perspective view similar to FIG. 4, illustrating the manner in which the form is removed from the cast concrete, FIGS. 6 and 7 are perspective views, from different angles, of one of the corner pieces of the window form of FIG. 1, FIG. 8 is a modification of a corner piece usable in the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, such figure shows a horizontally disposed casting pad 10, with an outer form 11 and a window form 12 assembled thereon so that a concrete wall can be cast. The outer form 11, used to define the perimeter of the wall, is made of members 11a, 11b, 11c and 11d, each having an appropriate length so that the cast wall will have a desired length and height. The outer form members extend upwardly from the casting pad 10 a distance equal to the desired thickness of the wall. A conventional patterned sheet mold 13 may be laid on the casting pad 10 to form a complementary pattern or design on the face of the wall which contacts such mold. For example, the mold 13 as illustrated herein will provide a simulated brick appearance to the finished wall. The window form 12 likewise has overall dimensions to give the desired size window opening, and extends upwardly from the casting pad a distance equal to the desired thickness of the wall. FIG. 2 illustrates a finished wall 15 which has been cast using the form of FIG. 1, the forms having been removed and the wall raised to a vertical position. Such wall has its outer surface 16 with the brick pattern of mold 13 imparted to it. The window form 12 has formed a stepped window opening 17 in the wall, such window opening having an outwardly facing shoulder 18 generally parallel to the wall surface 16 and extending around the periphery of the window. The window opening also has surfaces 19 and 20 generally perpendicular to the wall, surfaces 19 extending from shoulder 18 to the inner surface of the wall and surface 20 extending from shoulder 18 to the outer wall surface 16. If desired, the window form 12 may be suitably shaped so that one or more of the surfaces 20 will slope outwardly frm the shoulder 18. For example, it is common practice to slope the lowermost surface 20 downwardly for rain water drainage and to facilitate opening and closing of a window installed in opening 17. Window opening 17 also has window hinges 21 cast in place at desired locations in surface 20 so that casement windows (not shown) can be mounted thereon. The window form 12 comprises four elongated form members 12a, 12b, 12c and 12d, and a corner piece 25 disposed at each corner of the form, the shape of these form members and corner pieces being best illustrated in FIGS. 3-7. Form sections 12a-d each have a central member 26, which is generally rectangular in cross-section, such member having an outwardly facing casting surface 27 thereon extending along the upper length of the central member from one end to the other. Such casting surface 27 will form the surface 20 in one side of the window opening 17. Each form section member also includes a second member 28 extending along the central member 26. Preferably the ends 29 of the second member 28 terminate short of the ends 30 of the central member 26 to expose an outwardly facing surface 31 on the lower part of the central member 26 at each end thereof. Member 28 has outwardly and downwardly extending casting surfaces 32 and 33 which are utilized to form the surfaces 19 and 20 respectively of the window opening. An inner member 35 is secured to central member 26 for reinforcement thereof, and extends substantially the full length thereof. Inner member 35 terminates short of the end face 30 of central member 26 so that the distance from the end face 36 of inner member 35 to the end face 30 of the central member 26 is at least equal to the thickness of the adjacent inner member 35. The inner member 35 has a screw 37 near each end thereof. When the form has been assembled, a corner bracket 38, having vertical slots 39, can be slipped over the shanks of screws 37, the screws then being tightened against the bracket to hold the form members securely together. The corner pieces 25 each comprise a block 41 having an L shape in horizontal cross-section. As shown in FIG. 3, leg 42 of the block is abuttable against the end 29 of the outer member 28 of form section 12a, leg 42 having outwardly and downwardly extending casting surfaces 43 and 44 which are coplanar with casting surfaces 32 and 33 of form section 12a to form an extension thereof when the form is assembled. Leg 45 of block 41 is likewise abuttable against the end of member 28 of form section 12d, leg 45 having outwardly and downwardly extending casting surfaces 46 and 47 coplanar with casting surfaces 32 and 33 of form section 12d. Each corner piece further comprises a post 48 which extends upwardly from the inner junction of the legs of block 41. Post 48 has adjacent sides 49 and 50 which form outwardly facing casting surfaces coplanar with the casting surfaces 27 on form sections 12a and 12d respectively when the form is assembled and the post is abutted against the ends 30 of the form sections. Post 48 is preferably rectangular in horizontal cross-section, and the width of side 49 is at least as great as the thickness of central member 26 of form section 12d so that form section 12a can be removed after casting. Likewise, the width of side 50 of the post is at least as great as the thickness of central member 26 of form section 12a so that form section 12d may be removed, after casting, while form section 12a is still in place. The legs of block 41 extend laterally beyond post 48 to provide bearing surfaces 51 (FIG. 6) which will engage surfaces 31 on the form sections for alignment purposes, when the form is assembled, the width of surfaces 51 and 31 being equal to each other. The corner pieces 25 are preferably molded from plastic and include a vertically extending retainer post 52 parallel to post 48, retainer post 52 being secured, by readily breakable bridge member 53 formed during the molding, to post 48 at the vertical corner of post 48 diagonally across from the junction of the sides 49 and 50 of the post 48. In use, the form sections 12a-12d are assembled together on the casting pad 10 as illustrated in FIGS. 3 and 4, with a corner piece 25 at each corner of the form and the screws 37 are tightened against brackets 38 to hold the form securely together. The retainer posts 52 bear against the inner surfaces of the central members 26 and thus hold the corner pieces in place. If desired, a right-angle corner plate 54 (FIG. 1) could be used in place of bracket 38 to secure the form sections together, such corner plate 54 being notched at its vertex to accommodate the retainer post 52 of the corner piece 25 at that corner. The assembled window form 12 is positioned on the casting pad at the desired location thereon and is secured to the pad by suitable means, not shown, so that the form is held against movement during casting of the wall. As will be noted in FIG. 3, the outer member 28 of form section 12d has a plurality of recesses 55 formed into the casting surface 33, these recesses being provided so that hardware elements may be positioned at a desired location on the form for casting into the concrete. Preferably the recesses are shaped complementary to the portion of the particular hardware element which is to be left exposed when it is cast in place so that the hardware element will not wobble in the recess. Each recess has a permanent magnet 56 countersunk therein so that the magnet will engage and hold the hardware element securely in place when it is inserted into the recess. FIG. 3 illustrates one of the hinges 21 being inserted into one of the recesses, hinge 21 having suitable anchors 57 projecting therefrom for embedment in the wall. The shape of the positioning recesses 55, the number thereof, and the specific location on the form sections will depend on the particular hardware that is to be used with the finished wall opening. After the form has been assembled and secured to the casting pad, it is oiled, or otherwise treated to prevent sticking to the finished wall cast thereby. Appropriate hardware is inserted in the recesses and held in place by the magnets. Suitable reinforcement bars will, of course, have been positioned between the outer form 11 and window form 12. Concrete is then poured, up to the level of the tops of forms 11 and 12. As soon as the concrete has set, the window form 12 may be removed. Screws 37 are loosened and the brackets 38 removed. The bridges 53 of the corner pieces are broken and the retaining posts 52 are removed. Any one of the form sections 12a-12d may then be pulled inwardly, as by use of handles 61 in FIG. 5, so that the outer member 28 is pulled out from under the shoulder 18 which has been formed in the concrete. It will be appreciated that the clearance between the end face 36 of inner member 35 and the central member 26 of the adjacent form section is no less than the thickness of the outer member 28. The form section is then moved straight up and removed. The other three form sections are similarly removed. The form sections may then be reused immediately in the casting of another while waiting for the just-cast wall to cure. The corner pieces 25 are pried out and discarded. During such removal of the form sections the magnets therein pull easily from the hardware associated therewith, leaving the hardware cast in place in the wall. If desired, the corner posts could be reused. Indeed, they could be originally made without the retainer posts, i.e., as illustrated in FIG. 8. However, if so used, then it is necessary to tape the corner posts to the form sections 12a-12d as the form is assembled so that the corner posts will hold in place for the pouring process. More time is required for the taping and tape marks will be imprinted into the finished window opening. As is apparent from the foregoing, the present invention provides a form which can be easily assembled and used to cast a stepped opening having a downwardly facing shoulder and which can be readily removed from the cast concrete without destruction of the form members (other than the destruction of the inexpensive corner pieces). Since the form sections 12a-12d are removable and reusable, fewer forms are required and it is thus economically feasible to make such forms with the precision that should be used so that the openings will have the exact dimensions and shapes desired and so that the hardware will be located in the cast opening at precisely the right places. Although the form sections may be made of wood, it is preferable to make them out of metal for greater durability and longer life. Although each of the form sections 12a-12d is shown as made up of three separate pieces, 26, 28 and 35, which are then secured together, the form sections could be made from a single piece of material, as long as the desired casting surfaces 27, 32 and 33 are provided and as long as the form sections have sufficient structural rigidity for the intended use. If the form sections are made of metal, it would be feasible to use a spot magnetization process to magnetize the form sections at the desired hardware locations so that separate magnets would not be needed. Although the drawings illustrate only the formation of a single window opening, as many window openings may be cast in a wall as needed. Additionally, the form members described herein can be used to form door openings as well.
A form for casting stepped openings in concrete walls, the form having four elongated form members arranged in a rectangle, each form member having outer casting surfaces thereon to form one side of the opening. A corner piece at each corner of the form engages the ends of the form members thereat and completes the casting surfaces thereof, the corner pieces and form members being shaped to allow translatory movement of the form members away from the sides of the opening cast thereby so that the form members may be removed from the opening. Selected of the form members have recesses in the casting surface thereof for reception of hardware to be cast into the wall, the hardware being held in the recesses by magnets.
Identify and summarize the most critical features from the given passage.
[ "BACKGROUND OF THE INVENTION This invention relates to forms for use in casting of concrete walls and more particularly to forms used in the casting of stepped openings in walls.", "It is a common practice in the construction of concrete buildings to build concrete houses to cast the walls or wall sections as slabs in horizontal forms.", "After the concrete has cured, the wall is raised to vertical position, moved into position with other walls of the structure and joined thereto.", "It is also common practice to cast the wall sections with suitably located door and window openings.", "In many instances, the specifications for a wall section will include one or more window or door openings having a stepped configuration to provide a shoulder against which a door or window is to close, and, in many instances, the specifications are such that when the wall is cast in its horizontal form, the shoulder of the opening is facing downwardly.", "In such case the dimensions of the opening at the upper surface of the poured slab are less than that at the bottom of the slab.", "It is a relatively simple matter to design a form having a shape which will give the desired stepped configuration to the opening.", "However, the construction of such forms represents a significant cost factor.", "Since the form is larger at the bottom it cannot be removed from the cast slab simply by pulling it out.", "Removal while the slab is still in place is usually accompanied by partial or complete destruction of the form.", "As a result, a new form is usually required for each opening to be cast.", "This increases the cost and increases the chances that the form will not have the precise dimensions desired.", "The forms can be removed through the larger side of the opening after the slab has cured and has been raised from the casting pad.", "However, this necessitates a long delay before any possible reuse of the form.", "Window and door openings in the finished wall must also be provided with appropriate hardware so that windows and doors can be hung in the opening.", "Usually such hardware is installed after the walls are in place, which is a relatively expensive procedure since it requires that holes be drilled into the concrete or that nail guns be used.", "There have been attempts to secure the hardware to the forms so that the hardware will be cast as the concrete is poured.", "This has not been too satisfactory since it is difficult and time-consuming to attach the hardware to the form.", "Also, the hardware must be very carefully positioned on the form so that the cast-in-place hardware will properly mate with the hardware on the doors and windows to be later installed.", "It is the principal object of the present invention to provide a form for a stepped opening in a cast concrete wall which can be easily removed after the initial set of concrete and can be promptly reused for forming another opening.", "It is a further object of the present invention to provide a form for openings in cast concrete walls which enables hardware to be easily secured to the form and precisely positioned thereon so that such hardware can be cast into the opening as the concrete is poured.", "SUMMARY OF THE INVENTION The form of the present invention comprises a separate form member for each side of the opening, each form member having casting surfaces for forming the desired stepped configuration of the opening.", "The maximum length of each form member is less than the smallest length of the opening it is forming so that the form member can be removed therefrom.", "Special corner pieces are provided at each corner of the form to complete the casting surfaces and to permit translatory movement of the form members out from under the downwardly facing shoulder cast into the opening so that the form members can be removed.", "The form members of the present invention are also provided with means for precisely located hardware to be cast into the opening, and are provided with magnets for holding hardware to the form as the concrete is poured.", "Other objects and advantages will become apparent in the course of the following detailed description.", "BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, forming a part of this application, and in which like parts are designated by like reference numerals throughout the same, FIG. 1 is a plan view of a casting pad with a wall and window form assembled thereon, the window form being constructed in accordance with the invention, FIG. 2 is a perspective view of a concrete wall cast from the forms of FIG. 1, FIG. 3 is a perspective view, partially exploded of the window form of FIG. 1, looking towards one corner thereof from outside of the form, FIG. 4 is a perspective view of the window form of FIG. 1, looking towards one corner thereof from the inside of the form, FIG. 5 is a perspective view similar to FIG. 4, illustrating the manner in which the form is removed from the cast concrete, FIGS. 6 and 7 are perspective views, from different angles, of one of the corner pieces of the window form of FIG. 1, FIG. 8 is a modification of a corner piece usable in the present invention.", "DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, such figure shows a horizontally disposed casting pad 10, with an outer form 11 and a window form 12 assembled thereon so that a concrete wall can be cast.", "The outer form 11, used to define the perimeter of the wall, is made of members 11a, 11b, 11c and 11d, each having an appropriate length so that the cast wall will have a desired length and height.", "The outer form members extend upwardly from the casting pad 10 a distance equal to the desired thickness of the wall.", "A conventional patterned sheet mold 13 may be laid on the casting pad 10 to form a complementary pattern or design on the face of the wall which contacts such mold.", "For example, the mold 13 as illustrated herein will provide a simulated brick appearance to the finished wall.", "The window form 12 likewise has overall dimensions to give the desired size window opening, and extends upwardly from the casting pad a distance equal to the desired thickness of the wall.", "FIG. 2 illustrates a finished wall 15 which has been cast using the form of FIG. 1, the forms having been removed and the wall raised to a vertical position.", "Such wall has its outer surface 16 with the brick pattern of mold 13 imparted to it.", "The window form 12 has formed a stepped window opening 17 in the wall, such window opening having an outwardly facing shoulder 18 generally parallel to the wall surface 16 and extending around the periphery of the window.", "The window opening also has surfaces 19 and 20 generally perpendicular to the wall, surfaces 19 extending from shoulder 18 to the inner surface of the wall and surface 20 extending from shoulder 18 to the outer wall surface 16.", "If desired, the window form 12 may be suitably shaped so that one or more of the surfaces 20 will slope outwardly frm the shoulder 18.", "For example, it is common practice to slope the lowermost surface 20 downwardly for rain water drainage and to facilitate opening and closing of a window installed in opening 17.", "Window opening 17 also has window hinges 21 cast in place at desired locations in surface 20 so that casement windows (not shown) can be mounted thereon.", "The window form 12 comprises four elongated form members 12a, 12b, 12c and 12d, and a corner piece 25 disposed at each corner of the form, the shape of these form members and corner pieces being best illustrated in FIGS. 3-7.", "Form sections 12a-d each have a central member 26, which is generally rectangular in cross-section, such member having an outwardly facing casting surface 27 thereon extending along the upper length of the central member from one end to the other.", "Such casting surface 27 will form the surface 20 in one side of the window opening 17.", "Each form section member also includes a second member 28 extending along the central member 26.", "Preferably the ends 29 of the second member 28 terminate short of the ends 30 of the central member 26 to expose an outwardly facing surface 31 on the lower part of the central member 26 at each end thereof.", "Member 28 has outwardly and downwardly extending casting surfaces 32 and 33 which are utilized to form the surfaces 19 and 20 respectively of the window opening.", "An inner member 35 is secured to central member 26 for reinforcement thereof, and extends substantially the full length thereof.", "Inner member 35 terminates short of the end face 30 of central member 26 so that the distance from the end face 36 of inner member 35 to the end face 30 of the central member 26 is at least equal to the thickness of the adjacent inner member 35.", "The inner member 35 has a screw 37 near each end thereof.", "When the form has been assembled, a corner bracket 38, having vertical slots 39, can be slipped over the shanks of screws 37, the screws then being tightened against the bracket to hold the form members securely together.", "The corner pieces 25 each comprise a block 41 having an L shape in horizontal cross-section.", "As shown in FIG. 3, leg 42 of the block is abuttable against the end 29 of the outer member 28 of form section 12a, leg 42 having outwardly and downwardly extending casting surfaces 43 and 44 which are coplanar with casting surfaces 32 and 33 of form section 12a to form an extension thereof when the form is assembled.", "Leg 45 of block 41 is likewise abuttable against the end of member 28 of form section 12d, leg 45 having outwardly and downwardly extending casting surfaces 46 and 47 coplanar with casting surfaces 32 and 33 of form section 12d.", "Each corner piece further comprises a post 48 which extends upwardly from the inner junction of the legs of block 41.", "Post 48 has adjacent sides 49 and 50 which form outwardly facing casting surfaces coplanar with the casting surfaces 27 on form sections 12a and 12d respectively when the form is assembled and the post is abutted against the ends 30 of the form sections.", "Post 48 is preferably rectangular in horizontal cross-section, and the width of side 49 is at least as great as the thickness of central member 26 of form section 12d so that form section 12a can be removed after casting.", "Likewise, the width of side 50 of the post is at least as great as the thickness of central member 26 of form section 12a so that form section 12d may be removed, after casting, while form section 12a is still in place.", "The legs of block 41 extend laterally beyond post 48 to provide bearing surfaces 51 (FIG.", "6) which will engage surfaces 31 on the form sections for alignment purposes, when the form is assembled, the width of surfaces 51 and 31 being equal to each other.", "The corner pieces 25 are preferably molded from plastic and include a vertically extending retainer post 52 parallel to post 48, retainer post 52 being secured, by readily breakable bridge member 53 formed during the molding, to post 48 at the vertical corner of post 48 diagonally across from the junction of the sides 49 and 50 of the post 48.", "In use, the form sections 12a-12d are assembled together on the casting pad 10 as illustrated in FIGS. 3 and 4, with a corner piece 25 at each corner of the form and the screws 37 are tightened against brackets 38 to hold the form securely together.", "The retainer posts 52 bear against the inner surfaces of the central members 26 and thus hold the corner pieces in place.", "If desired, a right-angle corner plate 54 (FIG.", "1) could be used in place of bracket 38 to secure the form sections together, such corner plate 54 being notched at its vertex to accommodate the retainer post 52 of the corner piece 25 at that corner.", "The assembled window form 12 is positioned on the casting pad at the desired location thereon and is secured to the pad by suitable means, not shown, so that the form is held against movement during casting of the wall.", "As will be noted in FIG. 3, the outer member 28 of form section 12d has a plurality of recesses 55 formed into the casting surface 33, these recesses being provided so that hardware elements may be positioned at a desired location on the form for casting into the concrete.", "Preferably the recesses are shaped complementary to the portion of the particular hardware element which is to be left exposed when it is cast in place so that the hardware element will not wobble in the recess.", "Each recess has a permanent magnet 56 countersunk therein so that the magnet will engage and hold the hardware element securely in place when it is inserted into the recess.", "FIG. 3 illustrates one of the hinges 21 being inserted into one of the recesses, hinge 21 having suitable anchors 57 projecting therefrom for embedment in the wall.", "The shape of the positioning recesses 55, the number thereof, and the specific location on the form sections will depend on the particular hardware that is to be used with the finished wall opening.", "After the form has been assembled and secured to the casting pad, it is oiled, or otherwise treated to prevent sticking to the finished wall cast thereby.", "Appropriate hardware is inserted in the recesses and held in place by the magnets.", "Suitable reinforcement bars will, of course, have been positioned between the outer form 11 and window form 12.", "Concrete is then poured, up to the level of the tops of forms 11 and 12.", "As soon as the concrete has set, the window form 12 may be removed.", "Screws 37 are loosened and the brackets 38 removed.", "The bridges 53 of the corner pieces are broken and the retaining posts 52 are removed.", "Any one of the form sections 12a-12d may then be pulled inwardly, as by use of handles 61 in FIG. 5, so that the outer member 28 is pulled out from under the shoulder 18 which has been formed in the concrete.", "It will be appreciated that the clearance between the end face 36 of inner member 35 and the central member 26 of the adjacent form section is no less than the thickness of the outer member 28.", "The form section is then moved straight up and removed.", "The other three form sections are similarly removed.", "The form sections may then be reused immediately in the casting of another while waiting for the just-cast wall to cure.", "The corner pieces 25 are pried out and discarded.", "During such removal of the form sections the magnets therein pull easily from the hardware associated therewith, leaving the hardware cast in place in the wall.", "If desired, the corner posts could be reused.", "Indeed, they could be originally made without the retainer posts, i.e., as illustrated in FIG. 8. However, if so used, then it is necessary to tape the corner posts to the form sections 12a-12d as the form is assembled so that the corner posts will hold in place for the pouring process.", "More time is required for the taping and tape marks will be imprinted into the finished window opening.", "As is apparent from the foregoing, the present invention provides a form which can be easily assembled and used to cast a stepped opening having a downwardly facing shoulder and which can be readily removed from the cast concrete without destruction of the form members (other than the destruction of the inexpensive corner pieces).", "Since the form sections 12a-12d are removable and reusable, fewer forms are required and it is thus economically feasible to make such forms with the precision that should be used so that the openings will have the exact dimensions and shapes desired and so that the hardware will be located in the cast opening at precisely the right places.", "Although the form sections may be made of wood, it is preferable to make them out of metal for greater durability and longer life.", "Although each of the form sections 12a-12d is shown as made up of three separate pieces, 26, 28 and 35, which are then secured together, the form sections could be made from a single piece of material, as long as the desired casting surfaces 27, 32 and 33 are provided and as long as the form sections have sufficient structural rigidity for the intended use.", "If the form sections are made of metal, it would be feasible to use a spot magnetization process to magnetize the form sections at the desired hardware locations so that separate magnets would not be needed.", "Although the drawings illustrate only the formation of a single window opening, as many window openings may be cast in a wall as needed.", "Additionally, the form members described herein can be used to form door openings as well." ]