A workpiece (W) transfer assembly (10) is provided for a progressive die type punch press. The assembly (10) includes a first crank bar (28) driven to oscillate about a first rock shaft (24) by the press ram, and a second crank bar (36) driven to oscillate about a second rock shaft (32) by the press ram. A horizontal linkage (40) extends between the first crank bar (28) and a workpiece engaging jaw (18). A vertical linkage (42) extends between the second crank bar (36) and the horizontal linkage (40). A linear bearing (48) interconnects the vertical linkage (42) and the horizontal linkage (40). A plate (44) having a vertically elongated slot (46) disposed therein is attached to the horizontal linkage (40). The first crank bar (28) extends through the slot (48) (46) and thereby imparts motion to the jaw (18). The combination of elements allow horizontal jaw ( 18) movement into and out of engagement with the workpieces (W), and lost motion transmission in the vertical direction for raising and lowering the jaw (18) relative to the stations.
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1. A workpiece transfer assembly (10) for a press of the type including a reciprocating member and a series of longitudinally spaced in-line stations wherein each station is a further progression of the workpiece (W) forming process, said assembly (10) comprising: a first cam (12) and a second cam (14) for actuation by the reciprocating member; a first cam follower means (16) actuated by said first cam (12) for driving a workpiece engaging jaw (18) in a horizontal direction laterally of the stations into and out of a workpiece engagement position; a second cam follower means (20) actuated by said second cam (14) for raising and lowering said jaw (18) in a vertical direction relative to the stations; said assembly (10) characterized by including said first cam follower means (16) including a first rock shaft (24), a pair of first rocker arms (26) longitudinally spaced from each other and each oscillatory about said first rock shaft (24), and a first crank bar (28) extending longitudinally parallel to said first rock shaft (24) and carried by said pair of first rocker arms (26); said second cam follower means (20) including a second rock shaft (32), a pair of second rocker arms (34) longitudinally spaced from each other and each oscillatory about said second rock shaft (32), and a second crank bar (36) extending longitudinally and parallel to said second rock shaft (32) and carried by said pair of second rocker arms (34); and motion transmitting means (22) disposed between said jaw (18) and said first (16) and second (20) cam follower means and operatively interconnecting said first and second crank bars (28, 36) for providing positive motion transmission to said jaw (18) for horizontal movement into and out of engagement with the workpieces (W) and for providing lost motion transmission in the vertical direction to allow said jaw (18) to be raised and lowered relative to the stations while said first cam follower means (16) remains in the workpiece engagement position.
2. An assembly (10) as set forth in
3. An assembly (10) as set forth in
4. An assembly (10) as set forth in
for engaging said motion transmitting means (22). 5. An assembly (10) as set forth in claim 4 2 further characterized by said first rock shaft (24) and said second rock shaft (32) extending in a parallel longitudinal direction relative to the stations. 6. An assembly (10) as set forth in claim 5 further characterized by said motion transmitting means (22) including a horizontal linkage (40) extending between said jaw (18) and said first crank bar (28) for transferring horizontal motion to said jaw (18) from said first cam follower means (16). 7. An assembly (10) as set forth in claim 6 further characterized by said motion transmitting means (22) including a vertical linkage (42) extending between said second crank bar (36) and said horizontal linkage (40) for transferring vertical motion to said jaw (18) from said second cam follower means (20). 8. An assembly (10) as set forth in claim 7 further characterized by said motion transmitting means (22) including a bearing means (48) interconnecting said horizontal linkage (40) and said vertical linkage (42) for allowing said horizontal linkage (40) to be moved relative to said vertical linkage (42). 9. An assembly (10) as set forth in claim 8 further characterized by said bearing means (48) comprising a linear type bearing (48) fixedly disposed on said vertical linkage (42) with said horizontal linkage (40) extending therethrough for providing unrestricted horizontal motion to said horizontal linkage (40). 0. An assembly (10) as set forth in claim 8 further characterized by including trolley support means (50) for supporting said motion transmitting means (22) and allowing unrestricted linear movement of said motion transmitting means (22) in the longitudinal direction. 11. An assembly (10) as set forth in claim 10 further characterized by said trolley support means (50) comprising a plurality of roller elements (52) disposed about a fixed guide member (54). 12. An assembly (10) as set forth in claim 11 further characterized by said guide member (54) comprising an elongated rail (54) having a constant rectangular cross section. 13. An assembly (10) as set forth in claim 12 further characterized by said trolley support means roller elements (52) comprising at least four of said roller elements (52) disposed against each of the wide faces of said rectangular guide member (54) and at least two of said roller elements (52) disposed against each of the narrow faces of said rectangular guide member (54). 14. An assembly (10) as set forth in claim 10 further characterized by including coupling means (56) for connecting one of said motion transmitting means (22) to another like motion transmitting means (22) and for allowing the two to operate in tandem during the workpiece (W) transferring operation. 15. An assembly (10) as set forth in claim 12 further characterized by said vertical linkage (42) including a second crank bar retaining means (62) for transferring vertical movement from said second crank bar (36) to said vertical linkage (42). 16. An assembly (10) as set forth in claim 15 further characterized by said second crank bar retaining means (62) comprising at least one roller element (62) disposed on each side of said second crank bar (36) for allowing unrestricted longitudinal movement of said vertical linkage (42) along said second crank bar (36). 17. An assembly (10) as set forth in claim 16 further characterized by said first (28) and second (36) crank bars being arcuate in cross-section over at least the portions thereof contacting said motion transmitting means (22). 8. An assembly (10) as set forth in claim 17 further characterized by said assembly (10) including assist means (66) for providing pressurized air to aid in overcoming a portion of the force required to move said motion transmitting means (22) vertically. 19. An assembly (10) as set forth in claim 15 further characterized by said first (16) and said second (20) cam follower means including safety clutch means (68) for disengaging said motion transmitting means (22) from actuation in response to a predetermined level of resistance encountered by said jaw (18). 20. An assembly (10) as set forth in claim 19 further characterized by said safety clutch means (68) comprising a driving arm (69) coextending adjacent each of said rocker arms (26, 34) including a slide member (70) having a seat portion (72) spring biased into engagement with said rocker arms (26, 34) disposed in said driving arms (69). 21. An assembly (10) as set forth in claim 20 further characterized by said driving arms (69) adjacent said first (26) and second (34) rocker arms each including a cam engaging element (78) disposed thereon for tracing the predetermined motion impaired by said first (12) and second (14) cams. 22. An assembly (10) as set forth in claim 21 further characterized by said first (12) and second (14) cams being of the linear plate type having a curvilinear slot (12, 14) disposed in each for reciprocation in a planar path. 23. An assembly (10) as set forth in claim 22 further characterized by both of said curvilinear slots (12, 14) of said first (12) and second (14) cams being disposed within an integral carrier plate (80). 24. An assembly (10) as set forth in claim 23 further characterized by said carrier plate (80) being attached adjacent the press reciprocating member. 25. A workpiece transfer assembly (10) for a press of the type including a reciprocating member and a series of in-line stations wherein each station is a further progression of the workpiece (W) forming process, said assembly (10) comprising: a first cam (12) of the linear plate type and a second cam (14) of the linear plate type for actuation by the reciprocating member; a first crank bar (28) driven to oscillate about a first rock shaft (24) by said first cam (12) for driving a workpiece engaging jaw (18) in a horizontal direction into and out of a workpiece (W) engagement position; a second crank bar (36) driven to oscillate about a second rock shaft (32) by said second cam (14) for raising and lowering said jaw (18) in a vertical direction relative to the stations, said first (24) and second (32) rock shafts extending in a parallel longitudinal direction relative to the stations; a horizontal linkage (40) extending between said first crank bar (28) and said jaw (18); a vertical linkage (42) extending between said second crank bar (36) and said horizontal linkage (40) including a linear bearing (48) interconnecting said vertical linkage (42) and said horizontal linkage (40); said assembly (10) characterized by said horizontal linkage (40) including a plate (44) disposed thereon having a vertically elongated slot (46) disposed therein through which said first crank bar (28) extends. |
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This invention relates generally to assemblies used to transfer workpieces through a machine having a reciprocating member. More particularly, the invention relates to an assembly which is driven by the ram of a punch press for engaging the workpieces to move them progressively from one die station to another so that a plurality of sequential operations may be performed on them.
Workpiece transfer assemblies for use in progressive die type punch presses are well known in the art. Examples of these are shown in U.S. Pat. Nos. 3,138,128 granted June 23, 1964, 3,421,637 granted Jan. 14, 1969, 4,198,845 granted Apr. 22, 1980, and 4,513,602 granted Apr. 30, 1985, all in the name of the inventor of the subject invention.
A common problem not effectively eliminated by the prior art technology rises when the workpieces are lifted above the surface of the die before they are moved to the next station, either because of workpiece shape on the nature of the forming operation. In the past, this lift and carry operation was preformed by complex rack and pinion assemblies, as shown in the U.S. Pat. No. 4,436,199 to Baba et al granted Mar. 13, 1984, or by devices that were bolted onto the workpiece engaging jaws, as shown in my U.S. Pat. No. 4,198,845. These prior art lifting devices were clumsy, difficult to maintain, and comparatively expensive to produce.
The subject invention provides a workpiece transfer assembly for a press of the type including a reciprocating member and a series of in-line stations wherein each station is a further progression of the workpiece forming process. The transfer assembly comprises a first cam and a second cam for actuation by a reciprocating member, a first cam follower actuated by the first cam for driving a workpiece engaging jaw in a horizontal direction into and out of a workpiece engagement position, and a second cam follower means actuated by the second cam for raising and lowering the jaw in a vertical direction relative to the stations. The transfer assembly is characterized by including a motion transmitting means disposed between the jaw and the first and second cam follower means which provides positive motion transmission to the jaw for horizontal movement into and out of engagement with the workpieces, and provides lost motion transmission in the vertical direction to allow the jaw to be raised and lowered relative to the stations while the first cam follower means remains in the workpiece engagement position.
The subject invention provides a sturdy operating design which is inexpensive to manufacture, readily adaptable to die changes in the press, and easily serviced.
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1 is a perspective view of the preferred embodiment of the subject invention;
FIG. 2 is an end view of the subject invention shown with cams removed; and
FIG. 3 is a rear view of the subject invention.
Referring to the figures, wherein like numerals indicate like or corresponding parts throughout the several views, a workpiece transfer assembly is generally shown at 10. The transfer assembly 10 is specifically adapted for operation with a press of the type including a reciprocating member, i.e., ram, and a series of in-line die stations wherein each station is a further progression of the workpiece forming process. For convenience, a plurality of workpieces W are shown in FIG. 1.
The assembly 10 comprises a first cam 12 and a second cam 14 for actuation by the reciprocating member. A first cam follower means, generally indicated at 16, is actuated by the first cam 12 for driving a workpiece engaging jaw 18 in a horizontal direction into and out of a workpiece engagement position (shown in phantom at 100 in FIG. 2). The second cam follower means, generally indicated at 20, is actuated by the second cam 14 for raising and lowering the jaw 18 in a vertical direction relative to the stations.
The transfer assembly 10 is characterized by including motion transmitting means, generally indicated at 22, disposed between the jaw 18 and the first 16 and second 20 cam follower means for providing positive motion transmission to the jaw 18 for horizontal movement into and out of engagement with the workpieces W and for providing lost motion transmission in the vertical direction to allow the jar 18 to be raised and lowered relative to the stations while the first cam follower means 16 remains in the workpiece engagement position.
The first cam follower means 16 comprises a first rock shaft 24, at least one, and preferably two, rocker arms 26 oscilatory about the first rock shaft 24, and a first crank bar 28 disposed on the distil end of the rocker arms 26. The first rock shaft 24 rotates axially in a plurality of fixed bearings 30. Therefore, as the first cam 12 reciprocates with the ram, the first rock shaft 24 is axially rotated within the bearings 30, and the first crank bar 28 oscillates in an arcuate path therewith. The first crank bar 28 engages the motion transmitting means 22, such that oscillation of the first crank bar 28 ultimately moves the jaw 18 horizontally into and out of engagement with the workpieces W, as will be described subsequently.
The second cam follower means 20 comprises a second rock shaft 32, at least one, and preferably two, rocker arms 34 oscillatory about the second rock shaft 32, and a second crank bar 36 disposed on the distil end of the rocker arms 34. The second rock shaft 32 is held minor mirror images of each other.
Turning now to FIG. 2, when the press ram is in the fully closed position, i.e., engaging the workpieces W in the die stations, the transfer assembly 10 is in the position shown in solid lines. As the ram begins its ascent, away from the workpieces W, the curvilinear slot in the first cam 12 urges the cam engaging elements 78 on the first cam follower means 16 to rotate about the first rock shaft 24, thus moving the horizontal linkage 40 with the attached jaw 18 into, or toward, the workpieces W. The jaw 18 moves toward a workpiece engagement position, shown in phantom at 100. A plurality of fingers 82, each corresponding to a workpiece in a die station, are mounted on the jaw 18 and engage the workpieces W when in the workpiece engagement position 100.
Before the press ram reaches the top of its ascent, and after the first cam follower means 16 has moved the jaw 18 into the workpiece engagement position 100, the curvilinear slot in the second cam 14 urges the second cam follower means 20 to rotate about the second rock shaft 32, thus driving the motion transmitting means 22 and the attached jaw 18 above the surface of the dies, as shown in phantom at 200. It will be appreciated that during the workpiece W lifting operation, the lost motion provided in the slot 46 is imparted to the first cam follower means 16 while it means in the workpiece engagement position. At the workpiece lifted position 200, the indexing means moves the motion transmitting means 22 along with the jaw 18 and the workpieces W, longitudinally along the dies a predetermined distance. The predetermined distance, of course, being equal to the distance between die stations.
During the indexing operation, the press ram has reached its maximum height, and has just begun its descent. As the ram descends, the cam engaging element 78 of the second cam follower means 20 begins to retrace the curvilinear slot in the second cam 14, thereby urging the motion transmitting means 22 to lower the workpieces W into their new die stations. At this, the transfer assembly 10 returns to the workpiece engagement position 100, and places the workpieces W into their new die stations. The first cam 12 then urges the jaw 18 to retract from the workpiece engagement position 100, thus returning the transfer assembly 10 to the solid line position shown in FIG. 2. At this, the press ram has almost closed down upon the workpieces W in their new die stations. The indexing means next retract the motion transmitting means 22 back to the starting position so that the fingers 82 on the jaw 18 will be in the corresponding position of their original die stations. Thus, one complete cycle of the transfer assembly 10 has been described. It will be understood, that each complete transfer cycle is performed with every full cycle of the press ram.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many 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, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.
Sofy, Hugh M., Farhat, Dennis P.
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