LOCKING SYSTEM FOR FEEDING DEVICE OF A TRANSFER PRESS

Abstract: A locking mechanism is provided for use in conjunction with an electronic transfer feed system of a transfer press (10). The locking mechanism (110) includes a first gear (118) that has a plurality of external gear teeth disposed around its outer diameter. The first gear (118) is coupled to the shaft of drive assembly of the electronic transfer feed system. The locking mechanism also includes a second gear (136) that has a plurality of internal gear (118) teeth disposed around its inner diameter. The second gear (136) is sized such that when it is disposed around the first gear (118), the internal gear teeth of the second gear mesh with the external gear teeth of the first gear.

Description: LOCKING SYSTEM FOR FEEDING DEVICE OF A TRANSFER PRESS TECHNICAL FIELD OF THE INVENTION The present invention relates generally to the field of transfer press technology and more particularly to a system and method for locking an electronic transfer feed system in a transfer press. BACKGROUND OF THE INVENTION Sheet metal is used to form the basic components of many commercial products. For example, sheet metal is used to form parts for automobiles, appliances, airplanes and other mass produced items. To transform the sheet metal into an appropriately sized and shaped part, the sheet metal is pressed, bent, cut, pierced, trimmed, or altered in some other similar fashion. A transfer press is typically used to expedite the process of forming parts from sheet metal . At a basic level, most transfer presses include a press bed supporting one or more lower dies, a slide carrying one or more upper dies corresponding to the lower dies, and a crown for raising and lowering the slide relative to the press bed. Components are formed by positioning work pieces between the upper and lower dies and lowering the slide to press the material of the work piece between the upper and lower dies, thus modifying the work piece between the dies according to the configuration of the dies. Transfer presses typically include several upper and lower die combinations, typically referred to as press or work stations, that are arranged in a line within the transfer press . The dies for each work station are chosen to perform specified functions to create the desired part. A transfer press with such multiple work stations typically includes an automated system that transfers the parts from one station to the next to increase the rate of output by the transfer press. Such a system may be referred to as an electronic transfer feed system. Many transfer presses have a locking mechanism that is used to prevent the raising or lowering of the slides when desired. One example of such a slide locking mechanism may be found in U.S. Patent 5,269,059 issued to Rozenbojm, entitled Method of Installing a Slide Locking Mechanism in a Press . Slide locking mechanisms are typically operable to immobilize the slide once its reciprocation has been stopped. These locks ensure that once the slide is stopped, it will not restart, for example, when a technician is in the press performing maintenance or other operations . SUMMARY OF THE INVENTION Accordingly, a need has arisen for a system and method that can temporarily prevent the motion and operation of an electronic transfer feed system. The present invention provides an electronic transfer feed locking system that meets this need. According to one embodiment of the invention, a locking mechanism is provided for use in conjunction with an electronic transfer feed system of a transfer press. The locking mechanism includes an internal gear that has a plurality of external gear teeth disposed around its outer diameter. The internal gear is coupled to the shaft of a drive assembly of the electronic transfer feed system. The locking mechanism also includes an external gear that has a plurality of internal gear teeth disposed around its inner diameter. The external gear is sized such that when it is disposed around the internal gear, the internal gear teeth of the external gear mesh with the external gear teeth of the internal gear. The locking mechanism further includes a pivot arm coupled at one end to the external gear and at an opposite end to a piston. The pivot arm is also pivotally coupled to a lock frame such that a force applied to the piston will operate to pivot the pivot arm and move the external gear such that it meshes with the internal gear. This meshing prevents the rotation of the shaft of the drive assembly, and thus the operation of the electronic transfer feed system. Embodiments of the present invention provide numerous technical advantages. For example, embodiments of the invention may be used to prevent the operation of one or more aspects of an electronic transfer feed system in a transfer press. By preventing the operation of the electronic transfer feed system, the safety of the transfer press is enhanced. For example, embodiments of the present invention may be used to prevent the operation of one or more aspects of the electronic transfer feed system while a technician is working on the associated transfer press, or while an operator is changing parts or adding working pieces in the press. Other technical advantages are readily apparent to one skilled in the art from the following figures, descriptions, and claims. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following descriptions taken in connection with the accompanying drawings in which: FIGURE 1A is a schematic diagram showing an elevation view of a transfer press incorporating teachings of the present invention; FIGURE IB is a schematic diagram showing an end view of the transfer press of FIGURE 1A; FIGURE 1C is a schematic diagram showing an elevation view of portions of the transfer press of FIGURE 1A, shown alongside FIGURE IB in a position corresponding to their position in FIGURE IB; FIGURE 2 is a schematic diagram showing an elevation view of a clamp drive assembly of the transfer press of FIGURE LA; FIGURE 3A is a schematic drawing of a clamp locking mechanism of the clamp drive assembly of FIGURE 2 ; FIGURE 3B is a schematic drawing of the clamp locking mechanism of FIGURE 3A, with portions shown in a locking orientation; FIGURE 4A is a schematic diagram showing an elevation view of a lift drive assembly of the transfer press of FIGURE 1A; FIGURE 4B is a schematic diagram showing an end view of the lift drive assembly of FIGURE 4A; FIGURE 5A is a schematic diagram showing an elevation view of a transfer drive assembly of the transfer press of FIGURE LA; FIGURE 5B is a schematic drawing in cross-section taken along line 5B-5B of FIGURE 5A; FIGURE 6A is a schematic drawing of a transfer locking mechanism of the transfer drive assembly of FIGURE 5A; and FIGURE 6B is a schematic drawing of the transfer locking mechanism of FIGURE 6A, with portions shown in a locking orientation. DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention and its advantages are best understood by referring to FIGURES 1 through 6B of the drawings, like numerals being used for like and corresponding parts of the various drawings. FIGURE 1A is a schematic diagram of a transfer press 10 incorporating teachings of the present invention. The present invention may be incorporated in numerous types of transfer presses, of which transfer press 10 is only one example. Transfer press 10 includes a first plurality of horizontal beams 12, referred to generally as first horizontal beams 12. First horizontal beams 12 may include a pair of horizontal support beams disposed approximately parallel to one another. Transfer press 10 also include a plurality of footings 14 disposed beneath and supporting first horizontal beams 12. Footings 14 may include isolators (not explicitly shown) that are operable to isolate transfer press 10 from vibrations and to minimize the forces exerted by transfer press 10 on surface 50. Surface 50 may comprise, for example, the bottom of a pit within which transfer press 10 operates . Transfer press 10 further comprises a plurality of press beds 16 supported, at least in part, by first horizontal beams 12. The top surfaces of press beds 16 support, either directly, or indirectly through another component, the lower dies (not explicitly shown) used in forming work pieces. The top surfaces of press beds 16 support bolsters 62, which carry the lower dies. Each bolster 62 includes a support member 63 for supporting and holding the lower die, a drive mechanism 64 disposed beneath support member 63, and wheels 65 affixed beneath drive mechanism 64. The number and position of wheels 65 may be selected to optimize stability and minimize deflection of bolster 62. Pedestals 66 may be coupled to bolster 62 to provide support to a pair of feed rails 72. Feed rails 72 comprise portions of an electronic transfer feed system (ETF) 70 that transports work pieces through transfer press 10. ETF 70 is described in further detail below. Transfer press 10 also includes a second plurality of horizontal beams 24 generally parallel to first horizontal beams 12 and press beds 16. The second plurality of horizontal beams, referred to generally as second horizontal beams 24, may include a pair of horizontal support beams disposed approximately parallel to one another. Second horizontal beams 24 may comprise structures similar to first horizontal beams 12. Second horizontal beams 24 need not, however, be identical to first horizontal beams 12, and indeed may vary considerably given the comparably lower load bearing requirement of second horizontal beams 24. Second horizontal beams 24 are supported by a plurality of vertical support structures 22 disposed between first horizontal beams 12 and second horizontal beams 24. Vertical support structures 22 include vertical support columns 23. Vertical support columns 23 are positioned between first horizontal beams 12 and second horizontal beams 24. Vertical support columns 23 provide load bearing support for second horizontal beams 24. Still referring to FIGURE 1A, transfer press 10 further comprises a plurality of crowns 28 coupled to second horizontal beams 24. A slide 30 is coupled to each crown 28. Each slide 30 is disposed between its respective crown 28 and one or more press beds 16. Crown 28 and slide 30 are connected through coupling members 32. Crowns 28 provide a mechanism for moving slides 30 vertically with respect to press beds 16. Each crown 28 may utilize, for example, a mechanical or a hydraulic drive mechanism to effect vertical movement of slide 30 relative to its respective press bed or beds 16. Crowns 28 implement a mechanical drive mechanism 34, and more particularly, a link drive. Other drive mechanisms, such as an eccentric drive could be utilized without departing from the scope of the invention. Each crown 28 is coupled to another crown 28 with a drive link 36. Transfer press 10 includes tie rods 26 extending from the top of crowns 28 through the bottom of first horizontal beams 12. Each tie rod 26 extends through one of vertical support columns 23 along its vertical axis. Each vertical support column 23 has a cavity (not explicitly shown) extending along its vertical axis through which tie rods 26 may extend. In one embodiment, the combination of vertical support columns 23 and tie rods 26 comprises vertical support structure 22. In that case, vertical support columns 23 provide load bearing support, while tie rods 26 assist in laterally stabilizing transfer press 10. First horizontal beams 12, second horizontal beams 24, and crowns 28 may include cavities (not explicitly shown) through which tie rods 26 may extend. Press beds 16 may also comprise such cavities (not explicitly shown) . The cavities in first horizontal beams 12, press beds 16, vertical support columns 22, second horizontal beams 24, and crowns 28 are aligned to allow tie rods 26 to extend continuously through all of these components, providing additional lateral support for transfer press 10. Fasteners 27 connect to each end of tie rods 26 to maintain the position of tie rods 26. Although a specific transfer press 10 has been described, other types of transfer presses may be used in conjunction with the present invention. For example, although transfer press 10 comprises a multi-station press having a unitary frame (comprising, for example, horizontal beams 12, 24 and vertical support structures 22), a transfer press may be utilized that has a modular construction. One example of such modular construction is a transfer press system that includes a number of independent presses placed adjacent to one another, each press supporting at least one work station with a frame structure. A work station is the area in which an upper and lower die pair are positioned. By placing such independent press mechanisms adjacent to one another, this modular design is capable of producing the same finished work piece as transfer press 10. In any modular design, a common transfer feed system, such as ETF 70, could be used to link the various independent presses and to transfer work pieces from one press to another until the finished product is formed. Furthermore, although transfer press 10 has been described as having horizontal beams 12, 24, as well as vertical support structures 22, presses having only vertical supports may also be used in conjunction with the present invention. In such a configuration, the press beds and the crowns could be supported directly by the vertical supports, instead of disposing these components on horizontal beams which are themselves supported by the ' vertical supports. In addition, one set of vertical supports could be used to support the press beds, and the press beds could then be used to support a second set of vertical supports that, in turn, support the crowns. However, the configuration described above in conjunction with transfer press 10 has the advantage of additional longitudinal support and stability that is added by the inclusion of horizontal beams 12, 24. Referring still to FIGURE 1A, in general operation, transfer press 10 acts to press, bend, cut and/or otherwise manipulate raw materials to form completed or partially completed work pieces. Each slide 30 carries at least one upper die (not explicitly shown) , and each press bed 16 supports at least one bolster 62 carrying a lower die (not explicitly shown) . Transfer press 10 forms work pieces by positioning raw materials between the upper and lower dies, lowering slide 30 to exert force on the dies, and performing a particular manipulation on the work piece according to the configuration of the dies. Each slide 30 may service one or more work station 40. The function performed at each work station 40 depends on the configuration of the dies associated with slide 30 and press bed 16, the weight of slide 30, and the presence or absence of various other optional components, which may affect the level and/or direction of the force exerted on the work piece. For example, pneumatic cushions (not explicitly shown) may, or may not reside beneath press beds 16 to absorb some of the force exerted by slide 30, or to allow complex die motions for deeper drawing operations in forming the work piece. In forming a work piece, bolsters 62 may be wheeled from under slides 30, and lower dies may be secured to bolsters 62 at floor level 25. Bolsters 62 may then be wheeled back into position under slides 30, which carry the upper dies. Feed rails 72 of ETF 70 transport raw materials or partially completed work pieces, which have been referred to generally as work pieces, into transfer press 10 at entry point 44. The work piece is first conveyed to work station 40a, where an initial draw may be performed. Once the work piece is located between the upper and lower dies, crown 28 lowers slide 30 to bring the upper and lower dies together, thereby modifying the material between them. Crown 28 then lifts slide 30 allowing feed rails 72 of ETF 70 to remove the modified work piece from under slide 30 and to transport it to the next work station. The area between work stations 40 include an idle or orientation station 45. Orientation station 45 provide an opportunity for the work piece to be reoriented prior to its entering the next work station. After leaving orientation station 45, the work piece continues through transfer press 10, being modified at each work station 40 until the work piece reaches exit point 48. At exit point 48, the modified work piece leaves press 10. The work piece may then be used in a fabrication process, such as an automobile assembly line. FIGURE IB is a schematic diagram showing an end view of transfer press 10 along line IB-IB of FIGURE 1A. FIGURE 1C is a schematic diagram showing an elevation view of portions of press 10, shown alongside of FIGURE IB in a position corresponding to their vertical position in FIGURE IB. Referring now to FIGURES 1A, IB and 1C, in order to move the work pieces through transfer press 10, ETF 70 operates feed rails 72a and 72b in the following three ranges: a transfer range 74, clamp ranges 75a and 75b, and a lift range 76. Transfer range 74 (shown in FIGURE 1A) is generally the distance along the longitudinal axis of transfer press 10 from entry point 44 to exit point 48. Generally, there is a separate pair of feed rails 72 for each slide 30, and each pair of rails 72 moves in a portion of transfer range 74 associated with that work station 40. However, rails 72 located along a common side of press 10 are linked together and thus move together along transfer range 74. Transfer range 74a is the range of movement of feed rails 72a and 72b, associated with work station 40a. The movement of work pieces through transfer range 74a is accomplished by feed rails 72a and 72b as follows. After the work pieces are placed in transfer press 10 at entry point 44, they are clamped and lifted by feed rails 72a and 72b. The clamping action is performed by actuating feed rail 72a in a clamp range 75a, and feed rail 72b in a clamp range 75b. Work pieces positioned between rails 72a and 72b can thereby be clamped by moving feed rails 72 together until they engage each side of the work piece. A set of fingers (not explicitly shown) may be attached to feed rails 72 to engage the work piece. The lifting action is performed by actuating feed rails 72a and 72b in lift range 76 such that rails 72 lift the work piece. Once the work piece has been clamped and lifted, feed rails 72a and 72b are moved along transfer range 74a until they reach work station 40a. Feed rails 72a and 72b move by sliding over rail supports 73a and 73b, respectively. Although rail supports 73 are stationary as rails 72 move in transfer range 74, rail supports 73 move with rails 72 in clamp range 75 and lift range 76. After moving along rail supports 73, feed rails 72a and 72b release the work piece in a position between the upper and lower dies of work station 40a. Feed rails 72a and 72b then retract to their original position before slide 30 reaches the work piece. This process is repeated by the other pairs of feed rails 72 until the work piece has been transferred through each work stations 40, at which point the work piece is deposited at exit point 48. The actuation of feed rails 72a and 72b, associated with work station 40a, in clamp ranges 75a and 75b, lift range 76, and transfer range 74a (shown in FIGURE 1A) is described below. A clamp rack-and-pinion assembly 78 is utilized to actuate rails 72a and 72b in clamp ranges 75a and 75b. Clamp rack-and-pinion assembly 78 is located in a lift- clamp module 77. A clamp drive assembly 100a is used to rotate a clamp pinion 79 that is in contact with a pair of clamp racks 80a and 80b (80b shown in FIGURE 1C) . As clamp pinion 79 rotates, teeth disposed around pinion 79 mesh with teeth disposed along clamp racks 80a and 80b, thereby causing clamp racks 80a and 80b to move laterally in opposite directions. Clamp racks 80a and 80b are, in turn, coupled to feed rails 72a and 72b, respectively, and thus move rails 72a and 72b laterally in their respective clamp ranges 75a and 75b. The direction of rotation of clamp pinion 80 determines whether the respective rails 72 move together or apart . Transfer press 10 also includes clamp drive assemblies 100b and 100c (shown in FIGURE 1A) that are associated with work stations 40b and 40c, respectively. Clamp assemblies 100b and 100c operate in a similar fashion as clamp drive assembly 100a in order to actuate their associated feed rails 72. Therefore, only the operation of a single clamp drive assembly 100 is described below in conjunction with FIGURE 2. A lift rack-and-pinion assembly 86 is utilized to actuate rails 72a and 72b in lift range 76. A pair of lift rack-and-pinion assemblies 86a and 86b are used to vertically actuate a pair of lift bars 88a and 88b, respectively, located in lift-clamp module 77. A lift drive assembly 200a is used to rotate a pair of lift pinions 87a and 87b that are in contact with a pair of lift racks (not explicitly shown) housed in assemblies 86. As lift pinions 87a and 87b rotate, teeth disposed around pinions 87a and 87b mesh with teeth disposed along the respective lift racks, and thereby cause the lift racks to move vertically. This rack-and-pinion operation is described further in conjunction with FIGURE 4B. Each lift rack is coupled to a respective lift rod 89a and 89b. Lift rods 89a and 89b are coupled to and move lift bars 86a and 86b, respectively. In turn, lift bars 86a and 86b are coupled to and move feed rails 72a and 72b, respectively, vertically in lift range 76. The direction of rotation of lift pinions 87a and 87b determines whether the respective rails 72a and 72b move up or down. Transfer press 10 also includes lift drive assemblies 200b and 200c (shown in FIGURE 1A) that are associated with work stations 40b and 40c, respectively. Lift assemblies 200b and 200c operate in a similar fashion as lift assembly 200a in order to actuate their associated feed rails. Therefore, only the operation of a single lift drive assembly 200 will described below in conjunction with FIGURES 4A and 4B. Finally, a pair of transfer rack-and-pinion assemblies 90 are used to move feed rails 72a and 72b, respectively, along the longitudinal axis of transfer press 10 in transfer range 74a. Rack-and-pinion assemblies 90a and 90b are actuated by transfer drive assemblies 300. The functions of transfer drive assemblies 300 and rack-and- pinion assemblies 90 are shown and described in further detail below in conjunction with FIGURE 5A. In summary, FIGURES 1A-1C illustrate transfer press 10 that is operable to form various work pieces. These work pieces are transferred through work stations 40 of transfer press 10 through the use of ETF 70. In order to enhance the safety of the transfer press, an ETF locking system is described below that may be used to immobilize ETF 70 from moving rails 72 in their transfer ranges 74, clamp ranges 75a and 75b, and lift range 76. Such a locking system may be engaged when a person is performing tasks such as maintenance on some aspect of transfer press 10. The ETF locking system may include a separate locking mechanism in each drive assembly that is operable to immobilize the aspects of ETF 70 actuated by that drive assembly. In the embodiment illustrated in FIGURES 1A and IB, there are two transfer locking mechanisms - one for each rail 72a and 72b, three clamp locking mechanisms - one for each work station 40, and three lift locking mechanisms - one for each work station 40. These individual locking mechanisms are described below. Transfer press 10 may include a larger or smaller number of transfer, clamp, and lift drive assemblies, and associated locking mechanisms, depending on the functions desired. FIGURE 2 is a schematic diagram showing an elevation view of one of the three clamp drive assemblies 100 of transfer press 10. The configuration of each clamp drive assembly 100 is similar, however, their orientation in transfer press 10 may differ. Clamp drive assembly 100 includes a motor 102 that is used to rotate a motor shaft 103. Motor shaft 103 is directly coupled to an input shaft 105 through the use of a coupling 104. Input shaft 105 is rotatably coupled to a gear reducer 106. Gear reducer 106 is used to reduce the rotational speed of input shaft 105 to the lower rotational speed of an output shaft 107. Output shaft 107 is coupled to the clamp pinion 79 (not explicitly shown in FIGURE 2) through the use of a coupling 108. As described above, the clamp pinion is in contact with and is operable to move the clamp racks 80 (not explicitly shown in FIGURE 2) . Finally, clamp drive assembly 100 includes a clamp locking mechanism 110 that is used to prevent the rotational motion of input shaft 105, and thus the clamping action of rails 72 of ETF 70. Referring now to FIGURE 3A, a schematic drawing of clamp locking mechanism 110 is shown. A "QD" bushing 114 is directly mounted to input shaft 105. In turn, bushing 114 is coupled to a brake disk 116 by a bolt 115, or other appropriate fasteners. One side of brake disk 116 extends to form an internal gear 118. Internal gear 118 has gear teeth 120 positioned around its outer diameter. Brake disk 116 may be used in conjunction with a braking system (not explicitly shown) , however, only internal gear 118 is needed for the operation of clamp locking mechanism 110. Therefore, bushing 114 may be coupled directly to internal gear 118 without brake disk 116. Alternatively, internal gear 118 may be coupled directly to input shaft 105 without the use of bushing 114. Clamp locking mechanism 110 also includes a lock frame 122. Lock frame 122 is mounted to gear reducer 106 through the use of a plurality of bolts 124, or other appropriate fasteners. It should be noted, however, that lock frame 122 has no interaction with gear reducer 106 and may be mounted to any other fixed object that might be located in sufficient proximity to internal gear 118. A piston-arm assembly 125 is mounted to lock frame 122. Piston-arm assembly 125 includes a piston 127 that is disposed within a cylinder 126. One end of a connecting rod 128 is coupled to piston 127. At an opposite end, connecting rod 128 is pivotally coupled to a pivot arm 130. Pivot arm 130 is pivotally mounted to lock frame 122 at a pivot point 132. Finally, pivot arm 130 is coupled at an end 134 to an external gear 136. External gear 136 has a set of internal gear teeth 138 formed around its inside diameter. The inside diameter of external gear 136 is approximately equal to the outside diameter of internal gear 118. Referring now to FIGURE 3B, clamp locking mechanism 110 operates as follows. Initially, the rotation of input shaft 105 should be stopped. The rotation of input shaft 105 may be stopped by turning off motor 102 or by applying pressure to brake disk 116. Once the rotation of input shaft 105 is stopped, clamp locking mechanism 110 may be actuated. This actuation is performed by directing a fluid, typically air, at high pressure into the rod end 140 of cylinder 126. This high pressure moves piston 127 towards the cap end 142 of cylinder 126 into a position 127'. By "high pressure" it is meant any pressure greater than the pressure existing at cap end 142 of cylinder 126. The motion of piston 127 moves connecting rod 128 into a position 128'. The motion of connecting rod 128, in turn, rotates pivot arm 130 about pivot point 132 into a position 130' . The rotation of pivot arm 130 into position 130' causes external gear 136 to move into a locking position 136' . End 134 of pivot arm 130 is allowed to move a small distance vertically in a slot 135 as pivot arm 130 moves external gear 136 horizontally. Slot 135 allows the angular motion of pivot arm 130 to be translated into the linear motion of external gear 136. In locking position 136', external gear teeth 120 of internal gear 118 mesh with internal gear teeth 138 of external gear 136. Due to the meshing of gear teeth 120 and 138, and because external gear 136 is not rotatably mounted, the rotational motion of internal gear 118 is prevented. Since internal gear 118 is coupled to input shaft 105, the rotational motion of input shaft 105 and motor shaft 103 is thereby prevented. This in turn prevents the actuation of rails 72 of the ETF 70 in clamp range 75. At all times during the operation of ETF 70, air pressure is directed to cap end 142 of cylinder 126. This air pressure at cap end 142 of cylinder 126 ensures that external gear 136 will remain in a unlocked position, as shown in FIGURE 3A, unless a greater air pressure is applied to rod end 140 of cylinder 126, as described above. Therefore, the default position of external gear 136 is in an unlocked position. FIGURE 4A is a schematic diagram showing an elevation view of one of three lift drive assemblies 200 of transfer press 10. The configuration of each lift drive assembly 200 is similar, however, their orientation in transfer press 10 may differ. Lift drive assembly 200 includes a motor 202 that is used to rotate a motor shaft 203. Motor shaft 203 is directly coupled to an input shaft 205 through the use of a coupling 204. Input shaft 205 is rotatably coupled to a gear reducer 206. Referring now to FIGURE 4B, an end view of lift drive assembly 200 taken along line 4B-4B of FIGURE 4A is illustrated. Gear reducer 206 is used to reduce the rotational speed of input shaft 205 to the lower rotational speed of lift pinions 87a and 87b. Lift pinions 87a and 87b are coupled to respective lift racks (not explicitly shown) located in lift rack-and-pinion assemblies 86a and 86b. Lift pinions 87a and 87b enter assemblies 86a and 86b, respectively, and mesh with and move the lift racks vertically inside assemblies 86. In one embodiment of the present invention, assemblies 86 are counterbalance actuators. Inside of assemblies 86a and 86b, the respective lift racks are coupled to and actuate lift rods 89a and 89b, respectively. As described above, lift rods 89 are used to actuated rails 72 in lift range 76. Returning to FIGURE 4A, lift drive assembly 200 further includes a lift locking mechanism 210 that is used to prevent the rotational motion of input shaft 205, and thus the lifting action of rails 72 of ETF 70. Lift locking mechanism 210 is configured and operates in the same manner as clamp locking mechanism 110, described in conjunction with FIGURES 3A and 3B. Therefore, lift locking mechanism 210 will not be described in further detail . FIGURE 5A shows an elevation view of transfer drive assemblies 300a and 300b of transfer press 10. Each drive assembly 300 is operable to actuate rails 72 in transfer range 24. Transfer drive assembly 300a moves rails 72a along rail support 73a, and transfer drive assembly 300b moves rails 72b along rail support 73b. Each transfer drive assembly 300 operates in a similar fashion (in fact, they operate in unison, as described below) , and thus only the operation of transfer drive assembly 300a will be described. Transfer drive assembly 300a includes a motor 302 that is used to rotate a motor shaft 303. Motor shaft 303 is directly coupled to an input shaft 305 through the use of a coupling 304. Input shaft 305 is rotatably coupled to a gear reducer 306. Gear reducer 306 is used to reduce the rotational speed of input shaft 305 to the lower rotational speed of a transfer pinion 308a. Pinion 308a extends from both sides of gear reducer 306. On one side pinion 308a is coupled to a corresponding pinion 308b of transfer drive assembly 300b by a coupler 309. The coupling of pinions 308a and 308b ensures that transfer drive assemblies move transfer rails 72a and 72b, respectively, in unison. The rotation of pinion 308a operates to actuate a rack 350 along the longitudinal axis of press 10. Rack 350 is coupled to a transfer carriage 352, and the longitudinal movement of rack 350 causes longitudinal movement of transfer carriage 352. The movement of transfer carriage 352, in turn, causes the movement of transfer rail 72a along rail support 73a. It should be noted that rack 350 and transfer carriage 352 are restricted to longitudinal movement generally parallel to transfer range 74, and cannot be actuated in clamp range 75 or lift range 76. For this reason, transfer carriage 352 is coupled to feed rail 72a through the use of a drive post 354. Drive post 354 is coupled to transfer carriage 352 in such a manner that the longitudinal motion of transfer, carriage 352 causes rail 72a to be actuated in transfer range 74, but the clamping and lifting movements of rail 72a are not translated to transfer carriage 352. Drive post 354 is coupled to transfer carriage 352 through the use of a base 356. Base 356 has a set of rollers 358 that allow it to roll along transfer carriage 352 in clamp range 75. Transfer carriage 352 is constructed to allow drive post 354 to travel through carriage 352 in clamp range 75. Furthermore, as illustrated in FIGURE 5B, a housing 360 that includes a second set of rollers 362 is coupled to rail 72a and disposed around drive post 354. Housing 360 and rollers 362 allow rail 72a to move along drive post 354 as rail 72a travels in lift range 76. Transfer drive assembly 300 further includes a transfer locking mechanism 310 that is used to prevent the rotational motion of input shaft 305, and thus the actuation of rail 72a in transfer range 74. Referring now to FIGURE 6A, a schematic drawing of transfer locking mechanism 110 is shown. Transfer locking mechanism 310 operates substantially the same as clamp locking mechanism 110, shown in FIGURES 3A and 3B. A "QD" bushing 314 is directly mounted to input shaft 305. In turn, bushing 314 is coupled to a brake disk 316 by a bolt 315, or another appropriate fastener. One side of brake disk 316 extends to form an internal gear 318. Internal gear 318 has gear teeth 320 positioned around its outer diameter. Brake disk 316 may be used in conjunction with a braking system (not explicitly shown) , however, only internal gear 318 is needed for the operation of transfer locking mechanism 310. Therefore, bushing 314 may be coupled directly to internal gear 318 without brake disk 316. Alternatively, internal gear 318 may be coupled directly to input shaft 305 without the use of bushing 314. Transfer locking mechanism 310 further includes a lock frame 322. Lock frame 322 is mounted to gear reducer 306 through the use of a plurality of bolts 324, or other appropriate fasteners. It should be noted, however, that lock frame 322 has no interaction with gear reducer 306 and may be mounted to any other fixed object that might be located in sufficient proximity to internal gear 318. A piston-arm assembly 325 is mounted to lock frame 322. Piston-arm assembly 325 includes a piston 327 that is disposed within a cylinder 326. A connecting rod 328 is coupled at one end to piston 327. Connecting rod 328 is pivotally coupled at its opposite end to a pivot arm 330. Pivot arm 330 is pivotally mounted to lock frame 322 at a pivot point 332. Finally, pivot arm 330 is coupled at an end 334 to an external gear 336. External gear 336 has a set of internal gear teeth 348 formed around its inside diameter. The inside diameter of external gear 336 is approximately equal to the outside diameter of internal gear 318. Referring now to FIGURE 6B, transfer locking mechanism 310 operates as follows. Initially, the rotation of input shaft 305 should be stopped. The rotation of input shaft 305 may be stopped by turning off motor 302 or by applying pressure to brake disk 316. Once the rotation of input shaft 305 is stopped, transfer locking mechanism 310 may be actuated. This actuation is performed by directing a fluid, typically air, at high pressure into the rod end 340 of cylinder 326. This high pressure moves piston 327 towards the cap end 342 of cylinder 326 into a position 327' . By "high pressure" it is meant any pressure greater than the pressure existing at cap end 342 of cylinder 326. The motion of piston 327 moves connecting rod 328 into a position 328' . The motion of connecting rod 328, in turn, rotates pivot arm 330 about pivot point 332 into a position 330'. The rotation of pivot arm 330 into position 330' thereby causes external gear 336 to move into a locking position 336'. End 334 of pivot arm 330 is allowed to move a small distance vertically in a slot 335 as pivot arm 330 moves external gear 336 horizontally. Slot 335 allows the angular motion of pivot arm 330 to be translated into the linear motion of external gear 336. In locking position 336', external gear teeth 320 of internal gear 318 mesh with internal gear teeth 338 of external gear 336. Due to the meshing of gear teeth 320 and 338, and because external gear 336 is not rotatably mounted, the rotational motion of internal gear 318 is prevented. Since internal gear 318 is coupled to input shaft 305 through bushing 314, the rotational motion of input shaft 305 and motor shaft 303 is thereby prevented. This in turn prevents the operation of rails 72 in transfer range 74. At all times during the operation of ETF 70, air pressure is directed to cap end 342 of cylinder 326. This air pressure at cap end 342 of cylinder 326 ensures that external gear 336 will remain in a unlocked position, as shown in FIGURE 6A, unless a greater air pressure is applied to rod end 340 of cylinder 326, as described above. Therefore, the default position of external gear 336 is in an unlocked position. Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims: WHAT IS CLAIMED IS: 1. A transfer press, comprising: a work station operable to receive a work piece and to manipulate the work piece; and an electronic transfer feed system operable to move the work piece into and out of the work station, the electronic transfer feed system comprising: a plurality of feed rails operable to hold the work piece; at least one drive assembly operable to move the plurality of rails in at least one direction; and an electronic transfer feed locking system operable to prevent the movement of the plurality of the feed rails by the at least one drive assembly. 2. The transfer press of Claim 1 wherein the electronic transfer feed locking system comprises at least one locking mechanism having: a first gear having a plurality of external gear teeth, the first gear coupled to a shaft of a respective drive assembly; a second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; and an actuator operable to selectively position the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the respective drive assembly. 3. The transfer press of Claim 2 wherein the actuator comprises: a piston; and a pivot arm coupled at a first end to the second gear and at a second end to the piston, the pivot arm pivotally coupled intermediate the first and second ends to a frame such that a force applied to the piston moves' the piston and thereby pivots the pivot arm, which moves the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the drive assembly. 4. The transfer press of Claim 1 wherein the at least one drive assembly comprises: a transfer drive assembly operable to move the feed rails in a transfer range; a clamp drive assembly operable to move the feed rails in a clamp range; and a lift drive assembly operable to move the feed rails in a lift range. 5. The transfer press of Claim 4 wherein the electronic transfer feed locking system comprises: a transfer locking mechanism operable to prevent the motion of the transfer drive assembly; a locking mechanism operable to prevent the motion of the clamp drive assembly; and a lift locking mechanism operable to prevent the motion of the lift drive assembly. 6. The transfer press of Claim 5 wherein the transfer locking mechanism, the clamp locking mechanism and the lift locking mechanism each comprise: a first gear having a plurality of external gear teeth, the first gear coupled to a shaft of a respective drive assembly of the electronic transfer feed system; a second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; a pivot arm coupled at a first end to the second gear and at a second end to a piston, the pivot arm further pivotally coupled intermediate the first and second ends to a frame such that a force applied to the piston moves the piston and thereby pivots the pivot arm, which moves the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the respective drive assembly. 7. An electronic transfer feed system, comprising: a plurality of feed rails operable to hold a work piece; at least one drive assembly operable to move the plurality of feed rails in at least one direction; and an electronic transfer feed locking system operable to prevent the movement of the plurality of feed rails by the at least one drive assembly, the electronic transfer feed locking system comprising at least one locking mechanism coupled to a respective drive assembly, the at least one locking mechanism having: a first gear having a plurality of external gear teeth, the first gear coupled to a shaft of the respective drive assembly of the electronic transfer feed; a second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; and an actuator operable to selectively position the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the respective drive assembly. 8. The transfer press of Claim 7 wherein the actuator comprises: a piston; and a pivot arm coupled at a first end to the second gear and at a second end to the piston, the pivot arm pivotally coupled intermediate the first and second ends to a frame such that a force applied to the piston moves the piston and thereby pivots the pivot arm, which moves the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the drive assembly. 9. The electronic transfer feed system of Claim 7 wherein: the at least one drive assembly comprises: a transfer drive assembly operable to move the feed rails in a transfer range; a clamp drive assembly operable to move the feed rails in a clamp range; and a lift drive assembly operable to move the feed rails in a lift range; and the at least one locking mechanism comprises: a locking mechanism operable to prevent the movement of feed rails by the transfer drive assembly; a locking mechanism operable to prevent the movement of the feed rails by the clamp drive assembly; and a locking mechanism operable to prevent the movement of the feed rails by the lift drive assembly. 10. An electronic transfer feed locking system for use in an electronic transfer feed system, comprising: at least one locking mechanism operable to prevent movement of a portion of the electronic transfer feed system, the at least one locking mechanism having: a first gear having a plurality of external gear teeth, the first gear coupled to a shaft of a drive assembly of the electronic transfer feed; a second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; and an actuator operable to selectively position the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the respective drive assembly. 11. The transfer press of Claim 10 wherein the actuator comprises: a piston; and a pivot arm coupled at a first end to the second gear and at a second end to the piston, the pivot arm pivotally coupled intermediate the first and second ends to a frame such that a force applied to the piston moves the piston and thereby pivots the pivot arm, which moves the second gear such that the second gear meshes with the first gear, thereby preventing rotation of the shaft of the drive assembly. 12. The electronic transfer feed locking system of Claim 10 wherein the at least one locking mechanism comprises : a clamp locking mechanism operable to lock a clamp drive assembly of the electronic transfer feed system; a lift locking mechanism operable to lock a lift drive assembly of the electronic transfer feed system; and a transfer locking mechanism operable to lock a transfer drive assembly of the electronic transfer feed system. 13. The electronic transfer feed locking system of Claim 10 wherein the number of locking mechanisms equals the number of drive assemblies of the electronic transfer feed system, each locking mechanism coupled to a respective drive assembly to prevent the operation of the drive assembly. 14. A locking mechanism for use in conjunction with an electronic transfer feed system having a drive assembly having a shaft, comprising: a first gear having a plurality of external gear teeth, the first gear coupled to the shaft of the drive assembly of the electronic transfer feed; a second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; and an actuator operable to selectively position the second gear such that it meshes with the first gear, thereby preventing rotation of the shaft of the respective drive assembly. 15. The transfer press of Claim 14 wherein the actuator comprises: a piston; and a pivot arm coupled at a first end to the second gear and at a second end to the piston, the pivot arm pivotally coupled intermediate the first and second ends to a frame such that a force applied to the piston moves the piston and thereby pivots the pivot arm, which moves the second gear such that it meshes with the first gear, thereby preventing rotation of the shaft of the drive assembly. 16. The locking mechanism of Claim 15 further comprising a cylinder in which the piston is housed, the piston operable to move from a first end of the cylinder to a second end of the cylinder in response to a first fluid being introduced into the first end of the cylinder at a greater pressure than a second fluid located at the second end of the cylinder. 17. The locking mechanism of Claim 15 wherein the second gear further comprises a slot, the first end of the pivot arm coupled to the second gear in the slot such that the first end of the pivot arm can move in the slot to allow an angular movement of the pivot arm to move the second gear in a linear manner. 18. The locking mechanism of Claim 14 further comprising a QD bushing coupled directly to the shaft of the drive assembly and positioned between the first gear and the shaft so as to more securely couple the first gear to the shaft. 19. The locking mechanism of Claim 14 further comprising a brake disk to which force may be applied to slow and stop the rotation of the shaft of the drive assembly. 20. The locking mechanism of Claim 19 wherein the first gear is coupled to the brake disc and the brake disc is coupled to the shaft of the drive assembly. 21. A method of locking an electronic transfer feed system having at least one drive assembly having a shaft, comprising : positioning a locking mechanism adjacent the shaft of the at least one drive assembly of the electronic transfer feed system; preventing the rotation of the shaft of the at least one drive assembly by actuating the locking mechanism. 22. The method of Claim 21 wherein positioning the locking mechanism comprises: coupling an first gear having a plurality of external gear teeth to the shaft of a respective drive assembly; providing a second gear in proximity to the first gear, the second gear having a plurality of internal gear teeth and sized such that the internal gear teeth of the second gear may mesh with the external gear teeth of the first gear and such that the second gear may be disposed around the first gear; coupling a pivot arm at a first end to the second gear and at a second end to a piston; and pivotally coupling the pivot arm intermediate the first and second ends to a lock such that a force applied to the piston will operate to move the piston and thus pivot the pivot arm, thereby moving the second gear such that the second gear meshes with the first gear. 23. The method of Claim 22 wherein actuating the locking mechanism comprises applying a force to a first side of the piston in order to move the piston, and thereby pivot the pivot arm to move the second gear such that the second gear meshes with the first gear.

Inventors: BRZEZNIAK EDWARD J, BRZEZNIAK, EDWARD, J.
Applicants: VERSON A DIVISION OF ALLIED PR, VERSON, A DIVISION OF ALLIED PRODUCTS CORPORATION
Application year: 2000
Main classification: B21D43
IPC codes: B21D43, B21D55