US3125270A

US3125270A - Press feed mechanism

Info

Publication number: US3125270A
Authority: US
Publication date: 1964-03-17
Anticipated expiration: 1981-03-17

Description

March 1964 H. w. RONFELDT PRESS FEED MECHANISM 3 Sheets-Sheet 1 Filed March 15, 1962 H. W. RON FELDT PRESS FEED MECHANISM March 17, 1964 3 Sheets-Sheet 2 Filed March 15, 1962 INVENTOR. W 1105117 612744 BY 5344'!- M M I March 17, 1 H. w. RONFELDT PRESS FEED MECHANISM Filed March 15, 1962 3 Sheets-Sheet 3 United States Patent 3,125,270 PRESS FEED MECHANISM Howard W. IRonfeldt, Kalamazoo, Mich, assignor to Power Control Products, Inc, a corporationof Illinois Filed Mar. 15,-1962,., Ser. No. 179,939 19 Claims. (til. 22614l) This invention relates generally to press feed mechanisms, and more particularly to a pneumatic feed mechanism for a press such as a punch press.

The primary object of the present invention is to provide a novel arrangement ofa pneumatic press feed mechparagraph [for accurately adjusting and varying the incremental feed of stock to the press.

.It .is still another object to provide novel means in the press feed mechanism of any of the foregoing paragraphs for delivering strip stock to the press at a relatively high speed.

It is still another object to provide novel air valve means for the movable jaw .of a press feed mechanism for accurately correlating the locking and unlocking movements of the movable jaw relative to the travel thereof.

It is still another object to provide a novel press feed mechanism construction which is easily and simply adjustable in height and approach to a press such as a punch press.

Other objects and features of the present invention will beapparentupon a perusalof the following specification and drawings in which:

FIGURE 1 .is a perspective view of the press feed mechanism of the subject invention applied to a punch ,press;

FIGURE 2 is a top plan view of the press feed mechanism of FIGURE 1;

FIGURE 3 is a cross sectional view of the structure shown in FIGURE 2 and taken substantially along the FIGURE 1;

FIGURE 7 is an enlarged cross sectional view of the air valve shown in FIGURE 1 and taken substantially along the line 7 -'7 of FIGURES l and 6;

FIGURE 8 is a partial view of the punch press of FIGURE 1 showing the crank shaft of the punch press in an end view with a portion-of the subject invention applied thereto.

The present embodiment isthe preferred embodiment, butfit is to be understood that changes can be made in the present embodiment by one skilled in the art without departing from the spirit and scope of the present invention.

Generally, the press feed mechanism of the subject invention comprises a jaw andchannel assembly or section and a cylinder andvalve assembly or section. The jaw and channel assembly and the cylinder and valve assembly are bolted together in an end-to-end relationship by certain means including four tie rods which provide for accurate alignment and cooperation between the various elements of the invention in a simple arrangement which permits easy assemblythereof. The jaw and channel assembly is arranged at the rod .end of the cylinder and includes a circular recess in oneend of the assembly and an O-ring carried in the recess for sealing the rod end of the cylinder. The valve is arranged at the head end of the cylinder and also includes a circular recess in one portion thereof with an O-ring disposed therein for sealing the head end of the cylinder. The valve further includes an internal passageway for delivering air directly to the head end of the cylinder. The end of the jaw and channel assembly which seals the rod end of the cylinder also includes means for sealing the piston rod of the cylinder against air leakage and is further provided with a passageway for delivering air to the rod end of the cylinder.

The jaw and channel assembly is carried by a bolster bracket and adjustment block arrangement which permits easy adjustment of the feed mechanism in height relative to the punch press and in spacing of the feed mechanism from the die or dies of the punch press. The bolster bracket and adjustment block arrangement may be secured at any position along substantially the entire length of the jaw and channel assembly. The jaw and channel assembly comprises a pair of spaced apart U- shaped channel members which carry the stationary jaw and the moving jaw of the feed mechanism. The stationary and moving jaws are formed to be open at one end thereof, and because of the lack of any interference \from the rest of the feed mechanism with the open ends of the jaws, the feed mechanism of the subject invention can carry strip stock of a width substantially greater than the length of the jaws. A tubular member is carried longitudinally of and within the confines of each of the channel members. The base portion of the movable jaw is provided with a hole form-ed transversely therethrough at each end thereof thereby permitting the movable jaw to slide on the tubular members and within the channel members. One of the tubular members is adapted to carry air to the stationary jaw (for operation thereof. The stroke of the movable jaw is adjusted by a stroke adjustment bar which is carried on the tubular members and within the channel members. The stroke adjustment bar is secured at any selected position to the tubular members by a unique securing arrangement which is particularly shown in FIGURE 5. The piston rod of the cylinder extends through the stroke adjustment bar to a connection with the base portion of the movable jaw.

Air for operating the movable jaw is delivered to the movable jaw through a tubular member which extends through the end of the jaw and channel assembly which is connected to the cylinder, over the stroke adjustment bar, and to the base portion of the movable jaw. The end of the tubular member which extends outwardly of the jaw and channel assembly is connected by a coupling to a flexible air line, the other end of which is connected to the valve assembly. A poppet valve is carried on the jaw and channel assembly at a position such that slightly before the piston of the cylinder reaches its outwardm-ost position and in engagement with a bumper the outer surface of the coupling of the connection of the tubular member and the flexible air line will operate the poppet valve.

Strip stock is delivered tfrom a suitable source to the press feed mechanism of the subject invention and initially passes over a roller assembly which is carried on the air valve at the head end of the cylinder. The strip stockthen passes over the cylinder and the jaw and channel assembly to the movable jaw. After passing between the upper portion and the base portion of the movable jaw, the strip stock passes through the upper portion and base portion of the stationary jaw, and from the sta- 3 tionary' jaw the strip stock is delivered to the die or dies of the punch press. The strip stock is aligned relative .to the jaws by a roller assembly which is shown in FIG- URES 2 and 4. The roller assembly comprises a pair of brackets which are secured to one upwardly extending side wall of the upper section of the movable jaw. The pair of brackets carry a threaded rod which may be secured to the bracket by screws. The threaded rod carries a pair of rollers in a spaced apart relationship to ,each other with the rollers depending from the threaded rod to intersect the plane of any strip stock passing through the jaws. By appropriate positioning of the rollers on the threaded rod, strip stock of various widths may be aligned for guidance through the jaws.

The novel air valve construction of the subject inven tion includes a unique time delay feature. The air valve comprises two valve bores, a jaw valve bore and a cylinder valve bore, each carrying a valve spool therein. The air conduits to the stationary and movable jaws are connected into the jaw valve bore in a spaced apart relationship to each other. The poppet valve which is operated by the air conduit to the movable jaw is connected into one end of the jaw valve bore. The other end of the jaw valve bore is connected to one end of another air conduit, the other end of which is connected to a second poppet valx e which is shown in FIGURE 8. The second poppet valve is operated by a cam assembly which is secured to the crank shaft of the punch press. The jaw valve bore is also provided with a pair of spaced apart exhaust ports. The cylinder valve bore is provided with a pair of ports connected therein in a spaced apart relationship to each other, and one of those ports is connected internally of the valve to the head end of the cylinder while the other of those ports is connected by an air conduit to the rod end of the cylinder. The cylinder valve bore is also provided with a pair of spaced apart exhaust ports. Each end of the cylinder valve bore is connected by a small passageway defining an orifice therein to the valve ports which are connected to the stationary and movable jaws, the stationary jaw port being connected by one orifice passageway to one end of the cylinder valve bore and the movable jaw port being connected by a second orifice passageway to the other end of the cylinder valve bore.

A source of air pressure is connected through a pressure port and suitable passageways in the valve to both valve bores and to each end of the jaw valve bore.

The operation of the subject invention may be generally described by beginning with the stationary jaw in the closed position, the movable jaw in the open position. and with the cylinder moving toward a retracted position. In this condition of the invention, both spools of the valve will be operated to the positions shown in FIGURE 7. When the movable jaw engages the stroke adjustment bar, the movable jaw will be positively stopped from further movement. The next action is the opening of the poppet valve cooperating with the cam assembly on the crank shaft of the punch press as shown in FIGURE 8. When the cam engages the poppet valve the valve opens, air pressure is relieved at one end of the jaw valve bore, and air pressure in the other end thereof will cause the jaw valve spool to move to the other end of its bore connecting the movable jaw port to the pressure port and the stationary jaw port to an exhaust port. This will cause the movable jaw to be operated to the closed position and the stationary jaw to be moved to its open position. Air pressure at the movable jaw port will pass through an orifice passageway formed in the end plate of the valve to one end of the cylinder valve bore. This air pressure will cause the cylinder valve spool to be moved to the other end of the cylinder valve bore connecting the head end of the cylinder to the pressure port and the rod end of the cylinder to an exhaust port. The time delay between the closing of the movable jaw and the operation of the cylinder to move the movable jaw toward the stationary jaw is determined by the size of the orifice passageway in the end plate of the valve. This orifice may be varied in size to produce different increments of time between the closing of the moving jaw and the extension of the cylinder. In one reduction to practice of the present invention it has been found that a five millisecond delay produced excellent gripping and moving operations on the strip stock.

Just before the cylinder reaches its maximum extended position, the poppet valve carried adjacent the rod end of the cylinder is operated to remove the air pressure at the opposite end of the jaw valve bore from that to which the crank poppet valve is connected. The cylinder will then bottom under substantially positive pressure as the jaw valve spool is returned to the position shown in FIGURE 7, energizing or operating the stationary jaw and releasing the movable jaw. Again, through another orifice in the other end plate of the valve described above, the cylinder valve spool is returned to the position shown in FIGURE 7 after a certain delay of time. With the stationary jaw then energized and with the movable jaw deenergized or released, the cylinder is then operated to carry the movable jaw to the rearward position determined by the stroke adjustment bar. The foregoing described cycle will automatically repeat, moving the strip stock through the punch press in accurate increments by a pushing of the strip stock through the released stationary jaw, by a gripping and holding of the strip stock with the stationary jaw, and a return of the movable jaw to the stroke adjustment bar, followed by an energization of the movable jaw, a release of the stationary jaw, and thereafter an extension of the cylinder to again move the strip stock throughthe released stationary jaw.

In detail, the press feed mechanism of the subject invention comprises a jaw and channel assembly indicated generally at ltl and a cylinder and valve assembly indicated generally at 11.

The jaw and channel assembly 10 comprises a pair of U-shaped channel members 12, a rear end plate 13, a stationary jaw 14, a movable jaw 15, a bolster bracket 16, a pair of adjustment blocks 17, a tubular member 20, and a rod or tubular member 21. The rearward end of each of the channel members 12 is secured to one end of the rear plate 13 by fasteners 23. The forward end of each channel member 12 is secured to one end of the base portion of the stationary jaw 14 by fasteners 30. The stationary and movable jaws 14 and 15 are of substantially similar construction and the cross sectional view of the movable jaw shown in FIGURE 4, and the hereinafter following description thereof, are sufiicient for a description of the stationary jaw 14.

The

tubular members

20 and 21 are each carried within the confines of one of the channel members 12, and the rearward end of each of the

tubular members

20 and 21 extends through the rear plate 13 and is secured thereto by a fastener or nut 24. The forward end of each

tubular member

20 and 21 extends through the base portion of the stationary jaw 14 and is secured thereto by a fastener or nut 25. The base portion of the movable jaw, indicated at 27 in FIGURES 3 and 4, has reduced portions at each end thereof which extend into the confines of the channel members 12. Those reduced portions are each provided with a hole therethrough in which a bushing 28 is carried, and the

tubular members

20 and 21 extend through those bushings 28 in a freely sliding relationship. The

tubular members

20 and 21 extend through comparable holes in the base portion of the stationary jaw 14, although no bushings are provided.

The upper surface of the base portion 27 of the movable jaw 15 is provided with a relatively shallow depression or cavity 31 which extends longitudinally centrally of the base portion 27. The depression 31 is covered by an elastomer sheet 32. The elastomer sheet 32 may be formed of any material such as rubber or neoprene. A plate 33 is secured to the upper surface of the base portion .the adjacent end of the depression 31.

27 by screws 34 which extend through the plate 33 and are threaded into suitable holes in the base portion 27. The plate 33 is provided with a substantially rectangular 'hole formed .therethrough substantially longitudinally centrally thereof. The holein the plate 33 is slightly .larger than the length and width of the depression 31.

This construction provides a substantial air seal between the elastomer 32 and the side marginal edges of the depression .31. A .piston member 35 .is positioned in the opening of the .plate 33 and rests upon the elastomer sheet 32. The piston member 35 has a thickness slightly greater than the thickness of the plate 33 and a length and width substantially equal to the length and width of the opening :in the plate 33. A tubular member 36, which is provided for delivering air under pressure to the depres- .sion .31 in thebase portion 27 of the movable jaw, is con- .material for the piston member .35 is hardened steel although when working highly polished strip stock a material such as nylon may be used.

The movable jaw 15 further comprises an upper ,jaw portion 40 against which the piston member 35 may react in clamping a strip stock, as strip stock'41, therebetween. The upper jaw portion 40 is substantially -U-shaped in cross section and is secured at oneend thereof .to the base portion 27 by a plurality .of bolts42. The otherend of the upper jaw portion 40 is not secured to the base portion 27, thereby permitting the movable jaw 15 to accept strip stock of a greater width thanthe length of the jaw.

The bolts 42 may be ,formed with depressions therein to receive an -Allen type wrench. The bolts 42 are positioned through the upper jaw portion-40 and in the'base portion 27 between one of the channel members 12 and A number of shims 43 are inserted between .the upper jaw portion 40 and the base portion 27 to provide asuitable spacing between the underside of the upper jaw portion 40 and the upper surface of the piston member 35 in the deenergized or-released position of the movable jaw 15 for easy passage of the strip stock 41 therethrough and for suitable clamping .and holding of the strip stock 41 by the movable jaw 15 upon the application of air under pressure to tube 36.

It has previously been noted that the stationary jaw 14 was constructed substantially similar to movable jaw 15. The stationary jaw 14 comprises a base portion similar to base portion 27 and carries a movable piston member therein in a manner substantially similar to piston member 35. Stationary jaw 14 also is provided with an upper jaw portion 45 similar to upper jaw portion 40 and is secured to the base portion by a plurality of bolts 46 similar to bolts 42. The depression in the base portion of the stationary jaw 14 does not receive air at the same end there of as depression 31 of movable jaw 15. The depression in the base portion of the stationary jaw l4lreceives air from the tubular member .26 through a passageway 47 formed in the base portion of the stationary jaw 14.

The bolster bracket assembly 16 and the adjustment blocks 17 provide the means for adjustably carrying the feed mechanism of the subject invention in any desired cooperation with the punch press. The bolster bracket assembly 16 comprises a pair of angle members 50, a pair .of angle members 51, and a cross piece 52. The angle members 51 are secured one at each end of the cross piece 52 in an integral assembly. One depending leg of each of the angle members 51 is provided with a longitudinally disposed slot 53, and one leg of each of the angle members 50 is provided with a projecting bolt 54. The angle cylinder 60 with the cylinder extending into therec ess members are secured to the face or bed of .the punch press by any suitable clamping means such as shown in .FIGURE 1. Each of the anglemembersJSl is positioned with its slot 53 on one of the projecting bolts 54 and suitable nuts 57 are threaded onto the bolts 54 to secure the angle members 51 in any selected vertically adjusted position relative to the angle members 56. The other leg of each angle member 51 extends substantially horizontally and the pair of those other legs are spaced apart a distance sufficient to receive the jaw and channel assembly 10 thereon. The adjustment blocks 17 are substantially L-shaped having one leg thereof extending over the upper surface of the channel members 12. The adjustment'blocks 17 are secured .to the horizontally :extending leg of the angle members 51 by a pair of bolts 58. The bolts 53 have end portions adapted to receive an Allen wrench, and the holes through the adjustment blocks 17 which receive the bolts 58 are countersunk toprovide a minimum projection of the bolt '58 above the upper surface of the adjustment block 17. It may then be seen that the adjustment blocks 17 will frictionally secure the channel members .12 of the jaw and channel assembly 10 therebetween and against the horizontally extending legs of the angle members 51 to substantially horizontally align the plane of the jaw and channel assembly 10. By loosening the bolts 58, the jaw and channelassembly 10 may be adjusted inposition toward or away from the die .or dies of the punchpress. The adjustabilitvofthe chan- .nel members 12 in the bolster assembly 16 and.the adjustability of the bolster assembly 16 provides a simple and versatile arrangement for accurately feeding strip stock to a punch press.

The cylinder and valve assembly 11 is secured to the rear plate 13 of thejaw and channel assembly 10 andextends rearwardly therefrom in a substantially horizontal direction. The cylinder and valve assembly 11 comprises .an air cylinder-60, a valve assembly 61 and a stock roller 1301a diameter substantially equal to the diameter of the cylinder and placing an O-ring 63 in the inner .end .of that recess. The sealing of the head .end of the cylinder is accomplished in a similar manner. As may .Ibe seen inFlGURE ,6,.the valve assembly 61 is somewhat T-shaped. The upwardly extending portion. is formed with a circular recess therein substantially of .a diameter of the cylinder 60, and an O-ring 64 is positioned in that recess. In the assembly andsealingof the cylinder 60,-the rod end thereof is inserted in the .recess of the rear plate 13 and againstthe O-ring 63, and the valve assembly 61 is mounted on the head end of the thereof and against the O-ring 64. This assembly is integrally connected as a unit by four tie rods 65 which may be seen in FIGURES l and 2. The rear plate 13 of the jaw and channel assembly 10 is provided with four threaded holes-equally spaced about the periphery of the recess formed therein and one end of eachof the tie rods 65 is threaded into one of those holes. The upwardly extending portion of the valve assembly 61 is also provided with four -holes,therethrough and equally spaced about the periphery of the recess therein, and the rearward ends of thetie rod 65 extend through those holes and slightly rearwardly of the valve assembly 61. Thestockroller assembly 62-comprises a roller 66 and a roller bracket 67. The roller-bracket 67 is provided with four holes therethrough in alignment with the rearwardly extendingend portions of the four tie rods 65, and theroller bracket 67 is'mounted upon those .end portions, as in FIGURE 1. Four nuts 70 are threaded on the rearwardly extending ends of the tie rods 65 to securely carry the cylinder 60 between the rear plate 13and the valve assembly 61, and to carry the stock roller assembly 62 to extend rearwardly and slightly above the valve assembly 61. The O-rings 63 and 64 will effectively prevent any air leakage from either the rod end or head end of the air cylinder 60. The portions of the tie rods 65 extending between the rear plate 13 and the valve assembly 61 are of a slightly larger diameter than the end portions which extend into those members. This formation of the tie rod 65 provides shoulders which will accurately align the planes of the recesses in the rear plate 13 and the valve assembly 61 parallel to each other and substantially perpendicular to the longitudinal axis of the air cylinder 66.

An adjustable leg assembly 61 is secured to the rearward end of the cylinder and valve assembly 11 by a bolt 72 to support the rearward end of the feed mechanism of the subject invention from the fioor of the area carrying the punch press.

The air cylinder 60 further comprises a piston assembly of a piston head 74 and a piston rod 75. The piston head 74 may be of any suitable construction known in the art and is secured to one end of the piston rod 75 within the cylinder 60. The piston rod 75 extends through a packing assembly 76 which is carried through .a suitable opening formed in the rear plate 13. The

rod side of the piston head 74 or the packing 76 may be formed to include a bumper to absorb any shocks produced when the piston head 74 bottoms against the rear plate 13. The piston rod 75 further extends through a stroke adjustment bar 77 and through the base portion 27 of the movable jaw 15. The piston rod at the portion thereof entering the base portion 27 of the movable jaw 15 carries a bumper 78 which may be seen in FIG- URE 4. The end portion of the piston rod 75 which extends through the base portion 27 is threaded to permit the movable jaw 15 to be secured to the end of the piston rod 75 by a nut 80.

The stroke adjustment bar 77 is shown in side elevation in FIGURE and, as may be seen therein, is formed with a slightly reduced portion at each end thereof extending into the confines of the channel members 12. The reduced portions at each end of the stroke adjustment bar 77 are provided with holes therethrough permitting the stroke adjustment bar to be slidably carried on the

tubular members

20 and 21. In order to adjustably secure the stroke adjustment bar to the

tubular members

20 and 21, the stroke adjustment bar is formed with a pair of slots 81 which extend from the holes carrying the tubular members 26 and 21 on a curve toward the center of the bar 77 and upwardly to terminate on the upper surface thereof as may be seen in FIGURE 2. Suflicient metal is removed from the slot 81 so that when the slots are closed, the walls of the holes carrying the

tubular members

20 and 21 will firmly and securely engage the outer surface of the tubular members 21) and 21 to maintain the stroke adjustment bar 77 effectively locked thereon. The slots 81 are adjustably closed by a pair of screws 82 which are threaded into the stroke adjustment bar 77 from the upper surface thereof through the slot 81 as may be seen in FIGURE 5. Thus it maybe seen that by loosening the screws 82, the stroke adjustment bar may be slid along the

tubular members

20 and 21 to any desired position and locked at the selected position by appropriate tightening of the screws $2.

The stroke adjustment bar 77 is further provided with .a Vernier adjustment assembly 34 and a notch 83 in the .upper surface thereof for clearance from the tube 36.

The vernier adjustment assembly 84 comprises a bushing member 85 which as may be seen in FIGURE 2, is journaled on the piston rod 75 and threaded into the hole in the stroke adjustment bar 77 through which the piston rod 75 extends. The Vernier adjustment assembly 84 further comprises a lock nut 86 which is threaded on the bushing 85 and which is used to lock the bushing 85 in any selected threaded position in the stroke adjustment 'desired point along the channel members 12. The return stroke of the movable jaw 15 is first approximately adjusted by securing the stroke adjustment bar at some selected position along the

tubular members

20 and 21. The movable jaw 15 on its return stroke will strike the Vernier adjustment assembly 84 of the stroke adjustment bar 77 by the engagement of the bumper 78 with the Vernier adjustment assembly 84. After the stroke adjust ment bar 77 is locked in position, the lock nut 86 may be loosened and the bushing threaded either inwardly or outwardly of the stroke adjustment bar 77 to finely limit the return stroke of the movable jaw 15. A tightening of the lock nut 86 completes the adjustment of the return stroke of the movable jaw 15.

Note has previously been made of the T-shape of the valve assembly 61 with the upward extending portion defining the head end of the cylinder 60. The detailed construction of the horizontally extending portion of the valve assembly 61 will be described hereinafter. The cross sectional view of the valve assembly 61 shown in FIG- URE 7 is a horizontal cross section of the valve assembly as shown in FIGURE 6 looking downwardly. This orientation of FIGURE 7 is noted to facilitate an understanding of the valve construction, and it may thereby be seen that the ports 90 and 91 extend upwardly through the valve body 92 with the port 90 being connected into the internal passageway 93 and the port 91 being connected into the internal passageway 94, both of which are shown in FIGURE 6. The other end of passageway 93 is connected into the head end of the cylinder 60, and the other end of passageway 94 is connected to one end of an air conduit 95. The other end of the conduit 95 is connected to the rear plate 13 of the jaw and channel assembly 10, and to a passageway 96 formed therein as may be seen in FIGURE 2; The passageway 96 delivers air to the rod end of the cylinder 60. Thus it may be seen that port 90 is in free air communication with the head end of the cylinder 60 and port 91 is in free air com munication with the rod end of the cylinder 60.

The valve body 92 of the valve assembly 61 is provided with a pair of valve bores 97 and 98 formed therethrough in a parallel spaced apart relationship to each other. One side of the valve body 92 and bores 97 and 98 are covered by the end cap 100 which is secured thereto by fasteners 101, and the opposite side of the valve body 92 is covered by an end cap 102 which is secured thereto by fasteners 103. The ports 90 and 91 open into the valve bore 97, which may be designated the cylinder valve bore 97, in a spaced relationship to each other. Valve bore 98, which may be designated the jaw valve bore 98-, is provided with a pair of

ports

105 and 106 formed through the valve body 92 in a spaced apart relationship to each other. Port is connected to one end of an air conduit 10-7 the other end .of which is connected to the jaw release valve 108. The

jaw release valve 108 which is shown in FIGURES 1 and 2 is provided for delivering air to the stationary jaw 14. The valve .198 is therefore connected to the end of the tubular member 20 which has previously been described as connected into the cavity beneath the piston of the stationary jaw 14. The releasing function of the valve 108 'to the rearwardly extending end of tubular member 36 by a coupling member 111. The tubular member 36 has pre- 9 viously been described as providing a passageway for air to the movable jaw 15.

The coupling member 111 serves a further function in addition to providing a connection between conduit 110 and tubular member 36, and that function is as an operator for the return poppet valve 112. The poppet valve 112 is secured by a bracket 113 to the rear plate 13 at a position such that when the movable jaw 15 is almost at its extreme forward position, the outer surface of the coupling 111 will engage the return poppet valve 112 and open the poppet valve 112 to release any air under pressure therefrom. Thus it may be seen that the return poppet valve 112 is operated immediately before the piston head 74 and the bumper thereon bottoms against the rear plate 13. The return poppet valve 112 is connected to one end of an air conduit 114, the other end of which is connected to a port 115 formed through the end cap 109 and into one end of the jaw valve bore 9 8.

The other end of the jaw valve bore 98 is provided with a port 116 which is formed through the end cap 102 and is connected to one end of an air conduit 117. The other end of the air conduit 117 is connected to a poppet valve 118 particularly shown in FIGURE 8. When the poppet valve 118 is operated, any air under pressure in port 116 is released therefrom into the atmosphere. The poppet valve 118 is mounted in cooperation with the crank 120 of the press 121 by a bracket 122. The ball of the poppet valve 118 is positioned to engage the projecting end of a cam member 123 which is secured to the crank 126 by a clamping member 124. The cam member 123 is so positioned on the crank 120 that the poppet valve 118 is operated at the time selected for release of the stationary jaw 14, operation of the movable jaw 15, and operation of the cylinder 16 to start the movable jaw 15 moving toward the stationary jaw 14.

The valve body 92 is further provided with four

exhaust ports

125, 126, 127 and 128, and a pressure port 129. The

exhaust ports

125 and 126 are formed through the valve body 92 into the cylinder valve bore 97 in a spaced apart relationship to each other. The exhaust ports 127 and 128 are formed through the valve body 92 into the jaw valve bore 98 in a spaced apart relationship to each other. As may be seen in FIGURE 6, the

exhaust ports

125 and 126 exhaust air from the cylinder valve bore 97 in a horizontal direction, while the exhaust ports 127 and 128 exhaust air from the jaw valve bore 98 in a downward direction.

The pressure port 129 is formed through the valve body 92 from the underside thereof upwardly into an area between the valve bores 97 and 98. The upper end of the pressure port 129 is connected by a short obvious passageway to both of the valve bores 97 and 98. A passageway 130 formed in the valve body 92 and a short passageway 131 formed in the end cap 160 connect the pressure port 129 to port 115. A passageway 132 formed in the valve body 92 and a short passageway 133 formed in the end cap 162 connect the pressure port 129 to the port 116. Passageways 13.1 and 133 are substantially smaller in diameter than

ports

115 and 116.

One end of an air conduit 135 is connected to the pressure port 129. The other end of the conduit 135 is connected to an oiler device 136 which may be of any suitable type known in the art. The other side of the oiler device 136 is connected to an air pressure regulator 137 which also may be of any suitable type known in the art. The other side of the regulator device 137 is connected to one side of a conventional air filter 133, and the other side of the air filter 138 is connected to a source of air under pressure 139. The air filter 138, the regulator device 137 and the oiler device 136 are supported from the rear plate 13 by a bracket 146 which is secured to the plate 13, as in FIGURE 2.

The valve assembly 61 further comprises a pair of valve spools 142 and 143. The valve spool 142 is slidably carried in the cylinder valve bore 97 for reciprocating movement therein between the end caps 106 and 162. The valve spool 142 is provided with three annular grooves 144, 145 and 146 positioned in a spaced apart relationship to each other longitudinally of the valve spool 142. The annular grooves 144, 145 and 146 are further so positioned that when the valve spool 142 engages end cap 102, pressure port 129 is connected in free air communication with port 91 by annular groove 145, and the exhaust port is connected by annular groove 144 to port 90. The annular grooves 144, 145 and 146 are further so positioned that when the valve spool 142 engages end cap 100, pressure port 129 is connected by annular groove 145 to port 90, and exhaust port 126 is connected by annular groove 146 to port 91.

Valve spool 143 is provided with three

annular grooves

143, 156 and 151 positioned in a spaced apart relationship to each other longitudinally of the valve spool 143. The annular grooves 145, 150 and 151 are further positioned so that when the valve spool 143 engages the end cap 101 pressure port 129 is connected by annular groove 150 to port 105 and port 166 is connected by annular groove 151 to the exhaust port 128. The annular grooves 148, 150 and 151 are further so positioned that when the valve spool 143 engages end cap 162, pressure port 129 is connected by annular groove 156 to port 166 and port 195 is connected by annular groove 14% to the exhaust port 127. Each end of the valve spool 143 is further provided with a pair of O-

rings

152 and 153 disposed in suitable annular grooves formed in the end portions of the spool 143 to effectively prevent any air leakage between the

ports

115, 116 and the outer periphery of the valve spool 143 be tween its end portions.

The remaining construction of the invention further importantly includes a passageway 154 formed in the end cap 100 and a passageway 155 formed in the end cap 102. Each of the passageways 154 and 155 is formed for at least one portion of its length of a certain reduced diameter as an orifice to provide a certain time delay between the movement of the valve spool 143 and the movement of the valve spool 142. One end of the passageway 154 opens into one end of the cylinder valve bore 97, and one end of the passageway 155 opens into the other end of the cylinder valve bore 97. The other end of the passageway 154 is connected to one end of a passageway 156 the other end of which is connected to port 105. The other end of the passageway 155 is connected to one end of a passageway 157 the other end of which is connected to the port 106.

FIGURES 2 and 4 show the use of a strip stock guide carried on the upper member 40 of the movable jaw 15. The strip stock guide comprises a pair of brackets 160 which are secured to one upwardly extending wall portion of the members 40 by bolts 161. The brackets 160 are each provided with a threaded hole therethrough for carrying a threaded rod 162. Screws 163 threaded through the brackets 160 are provided for securing the threaded rod 162 in some selected position transversely of the length of any strip stock. The threaded rod 162 carries a pair of spaced apart roller assemblies 164 which depend from rod 162 to intersect the plane of any strip stock carried by the movable jaw 15. The roller assemblies 164 include screws 165 for securing the roller assemblies 164 at some selected positions on the rod 162 for accurately guiding the strip stock through the movable jaw 15. Because one end of the jaws 14 and 15 are open, the subject invention may easily feed strip stock of a width greater than the length of the jaws 14 and 15. From FIGURE 2 it may be seen that one of the roller assemblies 164 may be moved outwardly to the extending end of the rod 162 to guide very wide strip stock through the jaws 14 and 15.

The detailed description of the operation of the present invention may begin with an assumption that the valve assembly 61 is operated to the position shown in FIG- URE 7, that the movable jaw 15 is disposed somewhere between the forward and return positions so that the 116 respectively. The air at each end of the valve spool 143 will be pressurized since the

poppet valves

112 and 118 respectively connected to conduits 114 and 117 are closed. Air under pressure will also pass from pressure port 129 through the jaw valve bore 98 and annular groove 150 to port 165. From port 105 the air under pressure will pass through conduit 1G7, valve 198, and tubular member 20 to the stationary jaw 14 to cause an operation thereof clamping any strip stock in the stationary jaw 14. Air under pressure from port 1115 passing through

passageways

156 and 154 to the cylinder valve bore 97 will have no effect at this time on the spool 142 since the spool 142 engages the end cap 102. Air under pressure from pressure port 129 will also enter the cylinder valve bore 97, annular groove 145, port 91, passageway 94, conduit 95 and passageway 96 in the end plate 13 to the rod end of the cylinder 61). Further at this time, the movable jaw 15 is released by virtue of the connection of port 106 to exhaust port 128, and the head end of the cylinder 60 is opened to the atmosphere through exhaust port 125. The piston 74 will then be retracted in the cylinder 60 until the movable jaw 15 engages the Vernier adjustment assembly 84 carried by the stroke adjustment bar 77. The invention will then remain in this operated condition until the cam member 123 on the crank 12% of the press engages the ball of the poppet valve 118 to open the poppet valve 118 releasing the air under pressure in the jaw valve bore 98 at port 116 to the atmosphere. The air under pressure at the other end of the jaw valve bore 98 will then act against the end of the valve spool 143 to move the valve spool 143 in engagement with end cap 102. With this operation of the valve spool 143, the stationary jaw 14 will be released by the exhaust of air from conduit 167, port 165, annular groove 148 and exhaust port 127. Air under pressure from port 129 will then be connected to operate the movable jaw 15 over the following circuit: jaw valve bore 98 and annular groove 150, port 106, conduit 110, and conduit 36 to the movable jaw 15. With the application of air under pressure from port 106 to the movable jaw 15, a portion of the air under pressure will pass through passageway 157, and the orifice passageway 155 in end cap 102 to the cylinder valve bore 97. Because of the orifice passageway 155, a certain time delay will occur before sufiicient pressure is developed at the end of the valve spool 14-2 to cause its movement to the other end of the valve bore 97 to engage end cap 1110. In one reduction to practioe of the subject invention it has been found that a 5 millisecond delay between the operation of the movable jaw 15 and the movement of the valve spool 142 to its other operated position was sufiicient to cause a firm gripping of the strip stock before the movable jaw 15 was moved toward the stationary jaw 14 to advance the strip stock. With the movement of the valve spool 142 to engage end cap 101 the rod end of the cylinder 60 is exhausted through port 126, and the air under pressure at port 129 is connected to the head end of the cylinder 6% over the following circuit: cylinder valve bore 97 and annular groove 145, port 9% and passageway 93 to the head end of the cylinder 60. The piston 74 will then be moved to move the movable jaw 15 until the coupling member 111 engages and operates the poppet valve 112. Slightly after the poppet valve 112 is operated, the momentum of the movable jaw 15 will cause a bottoming of the piston '74 against the end plate 13. The operation of the poppet valve 112 will cause air under pressure in the end of the jaw valve bore 98 at port 115 to be exhausted to the atmosphere, and since the other end of the valve spool 143 at port 116 is under pressure by virtue of air under pressure passing from port 129 through passageways 132 and 133 to port 116, valve spool 143 will be moved to the other end of jaw valve bore 98 to engage end cap 100. This movement of the jaw valve spool 98 will firstly cause a release of the movable jaw 15 and an operation of the stationary jaw 14. The movable jaw 15 will be released by air passing from tubular member 36, conduit 110, port 106, annular groove 151 and port 128 to the atmosphere. The stationary jaw is operated over a previously described circuit including pre sure port 129 and annular groove 150. A portion of the air under pressure being applied from annular groove 15-5) to port 105, will pass through passageway 156 and orifice passageway 154 in end cap to cylinder valve bore 97. Because of the orifice passageway 154, a certain time delay will occur before suflicient pressure is developed at the end of the valve spool 142 to cause its movement to the other end of the valve bore 97 to engage end cap 102. Thus the movable jaw 15 will be fully released and the stationary jaw 14 will firmly grip the strip stock, before the piston 74 is retracted in the cylinder 60. With the return of the valve spool 142 to the position shown in FIGURE 7, the air under pressure will be applied to the rod end of the cylinder 60 while the head end thereof is exhausted to the atmosphere to cause a return of the movable jaw 15 to the limit provided by the setting of the stroke adjustment bar 77. The above described operations of the invention will be continuously repeated in cycles to accurately advance the strip stock in predetermined increments as long as air under pressure is delivered to the pressure port 129.

Having described the invention what is considered new and desired to be protected by Letters Patent is:

1. A feed mechanism for incrementally delivering strip stock to a press comprising, bracket means for adjustably carrying the forward end of said feed mechanism immediately over the bed of a press, a pair of channel members carried in said bracket means in a horizontally spaced apart relationship, a stationary jaw secured between the forward ends of said channel members with the longitudinal axis of said stationary jaw being positioned transversely of said channel members, said stationary jaw being formed with the underside thereof substantially coplanar with the underside of said channel members whereby said channel members and said stationary jaw are positionable immediately over the bed of a press, an end plate secured between the rearward ends of said channel members and substantially perpendicularly intersected by the plane of said channel members, a movable jaw slidably carried between said channel members and said stationary jaw and said end plate with the longitudinal axis of said movablejaw being positioned transversely of said channel members, said movable jaw being formed with the underside thereof substantially coplanar with the underside of said channel members whereby said movable jaw is movable immedia'tely. over the bed of a press, reciprocating air cylinder and piston means secured to said end plate to extend substantially perpendicularly and rearwardly thereof, said reciprocating air cylinder and piston means connected to said movable jawabove the plane of the underside of said channel members for reciprocating movement of said movable jaw responsive to reciprocating operations of said air cylinder and piston means.

2. A feed mechanism for incrementally delivering strip stock to a press comprising, bracket means for adjustably carrying the forward end of said feed mechanism immediately over the bed of a press, a pair of channel members carried in said bracket means in a horizontally spaced apart relationship, a stationary jaw having strip stock gripping portions, said stationary jaw secured between the forward ends of said channel members with the longitudinal axis of said stationary jaw being positioned transversely of said channel members and with the opening between said strip stock gripping portions being positioned above the plane of said channel members, said stationary jaw being formed with the underside thereof substanl3 tially coplanar with the underside of said channel memversely of said channel members and with the opening between said strip stock gripping portions being positioned above said channel members, said movable jaw being formed with the underside thereof substantially coplanar with the underside of said channel members whereby said movable jaw is movable immediately over the bed of a press, reciprocating air cylinder and piston means secured to said end plate to extend substantially perpendicularly and rearwardly thereof, said reciprocating air cylinder and piston-means connected to said movable jaw above the plane of the underside of said channel members for reciprocating movement of said movable jaw responsive to reciprocating operations of said air cylinder and piston means.

3. In a feed mechanism as defined in claim 2, wherein said bracket means comprises releasable clampingmembers for releasably clamping said channel members at any selected longitudinal position on said channel members, said clamping members being formed so that the upper surface thereof is below the plane of the openings between said strip stock gripping portions of said stationary and movable jaws, said bracket means being securable to a press, and said bracket means being formed to permit positioning of said releasable clamping members immediately vertically above the bed of a press.

4. In a feed mechanism as defined in claim 2, wherein said bracket means comprises first bracket members securable to a press and having vertically extending portions, second bracket members adjustably secured to said first bracket members for selective positioning at different vertical positions, said second bracket members having horizontally extending portions spaced apart a distance sufiicient to support channel members thereupon in said horizontally spaced apart relationship, and a pair or" clamp- ,ing members, each of said clamping members secured to the upper surface of one of said horizontally extending portions of said second bracket members and against the outer side of one of said channel members, said clamping members having horizontally extending portions extending partially over the upper surface of said channel members in a clamping arrangement, said clamping members further being formed so that the upper surface thereof is below the plane of the openings between said strip stock gripping portions of said stationary and movable aws.

5. A feed mechanism for incrementally delivering strip stock to a press comprising, bracket means for adjustably carrying the forward end of said feed mechanism immediately over the bed of a press, a pair of channel members carried in said bracket means in a horizontally spaced apart relationship, a stationary jaw comprising a base member secured between the forward ends of said channel members with the longitudinal axis of said base member being positioned transversely of said channel members, said base member being formed with the underside thereof substantially coplanar with the underside of said channel members whereby said channel members and said base member are positionable immediately over the bed of a press, an end plate secured between the rearward ends of said channel members and substantially perpendicularly intersected by the plane of said channel members, a pair of tubular members, each of said tubular members secured between one end of said end plate and one end of said base member of said stationary jaw and within the confines of one of said channel members, a movable jaw journaled on said tubular members and having the end portions thereof carried within said channel members with the longitudinal axis of said movable jaw being positioned transversely of said channel members, said movable jaw being formed with the underside thereof substantially coplanar with the underside of said channel members whereby said movable jaw is movable immediately over the bed of a press, reciprocating air cylinder and piston means secured to said end plate to extend substantially perpendicularly and rearwardly thereof, said reciprocating air cylinder and piston means connected to said movable jaw above the plane of the underside of said channel members for reciprocating movement of said movable jaw responsive to reciprocating operations of said air cylinder and piston means.

6. In a feed mechanism as defined in claim 5, wherein said stationary jaw further comprises an upper jaw portion fixedly carried to and a certain distance above said base member thereof, said upper jaw portion comprising a relatively shallow plate member providing a relative minimum increase in height of the forward end of said feed mechanism above said channel members, said base member comprising an air piston arrangement including a cavity so that the piston of said arrangement is moved upwardly responsive to air under pressure delivered to said cavity to clamp any strip stock positioned between said air piston arrangement and said upper jaw portion, and one end of one of said tubular members extending through said base member of said stationary jaw and connected by a passageway in said base member in free air communication with said cavity, the other end of said one tubular member being adapted to receive air under pressure.

7. A feed mechanism for incrementally delivering strip stock to a press comprising, bracket means for adjustably carrying the forward end of said feed mechanism in cooperation with a press, a pair of channel members carried in said bracket means in a horizontally spaced apart relationship, a stationary jaw comprising a base member secured between the forward ends of said channel members with the longitudinal axis of said base member being positioned transversely of said channel members, an end plate secured between the rearward ends of said channel members and substantially perpendicularly intersected by the plane of said channel members, a pair of tubular members, each of said tubular members secured between one end of said end plate and one end of said base member of said stationary jaw and within the confines of one of said channel members, a movable jaw journaled on said tubular members and having the end portions thereof carried within said channel members with the longitudinal axis of said movable jaw being positioned transversely of said channel members, a stroke adjustment bar journaled on said tubular members between said movable jaw and said end plate with the end portions of said stroke adjustment bar carried within said channel members and with a longitudinal axis of said stroke adjustment bar being positioned transversely of said channel members, reciprocating air cylinder and piston means secured to said end plate to extend substantially perpendicularly and rearwardly thereof, the piston rod of said reciprocating air cylinder and piston means extending through an opening formed in said end plate and an opening formed through said stroke adjustment bar and connected to said movable jaw for reciprocating movement of said movable jaw between said stationary jaw and said stroke adjustment bar responsive to reciprocating operations of said air cylinder and piston means, and a valve assembly carried on the rearward end of said air cylinder and piston means for operating said air cylinder and piston means.

8. In a feed mechanism as defined in claim 7, wherein the holes in said stroke adjustment bar through which tubular members extend are reducible in diameter sufficiently to cause said stroke adjustment bar to securely frictionally grip said tubular members by means comprisl5 ing a slot formed transversely through each end of said stroke adjustment bar from the inward side of each of said openings therethrough and extending toward the center and upwardly to the upper surface thereof, and a pair of fasteners, each of said fasteners extending from the upper surface of said stroke adjustment bar through one of said slots and threaded into a portion of said stroke adjustment bar below said slots so that said slots are effectively closed to reduce the diameter of said openings when said fasteners are securely threaded into said stroke adjustment bar.

9. In a feed mechanism as defined in claim 7, wherein said stroke adjustment bar comprises a Vernier stroke adjustment means for accurately limiting the movement of said movable jaw in a direction away from said stationary jaw, said Vernier stroke adjustment means comprising a bushing member journaled on said piston rod and threaded into said stroke adjustment bar to extend outwardly of said stroke adjustment bar in the direction of said movable jaw, and a lock nut threaded on the outer surface of the bushing member for locking said bushing member in any selected threaded position in said stroke adjustment bar.

10. In a press feed mechanism having air operated stationary and movable jaws and a reciprocating air cylinder and pistons means operatively connected to said movable jaw for incrementally delivering strip stock to a press, a valve assembly comprising a jaw valve bore and a cylinder valve bore, a jaw port connected into said jaw valve bore, a cylinder port connected into said cylinder valve bore, a pressure port connected directly into said jaw valve bore and directly into said cylinder valve bore, a jaw valve spool slidably carried in said jaw valvenbore, meansfor moving said jaw valve spool to connect said pressure port and said jaw port, a cylinder valve spool slidably carried in said cylinder valve bore, said cylinder valve spool being formed to connect said pressure port and said cylinder port when said cylinder valve spool is moved away from one end of said cylinder valve bore by the application of air under pressure to said one end thereof, and a passageway having an orifice therein, said passageway connected between said jaw port and said one end of said cylinder valve bore, said orifice being formed as a restricted opening sufficiently small to provide a time delay between the application of any substantial air pressure at said jaw port and said one end of said cylinder valve bore.

11. In a press feed mechanism as defined in claim wherein said valve assembly comprises a body portion having said jaw valve bore and said cylinder valve bore formed therein and extending to one end thereof, and an end plate secured to said body portion over the ends of said jaw valve bore and said cylinder valve bore, and said passageway having an orifice therein comprising a recess formed in the surface of the side of said end plate which engages said body portion, said recess extending from said one end of said cylinder valve bore to a passageway formed in said body portion and connected to said jaw port, said orifice defined by one portion of said recess having a certain reduced cross sectional area and the cooperating portion of said body portion.

12. In a press feed mechanism having air operated stationary and movable jaws and a reciprocating air cylinder and piston means operatively connected to said movable jaw for incrementally delivering strip stock to a press, a valve assembly comprising a jaw valve bore and a cylinder valve bore, a pair of ports connected into said jaw valve bore in a spaced apart relationship to each other, one of said ports connected to said stationary jaw and the other of said ports connected to said movable jaw for operation thereof, a second pair of ports connected into said cylinder valve bore in a spaced apart relationship to each other, one of said second pair of ports connected to the head end of said air cylinder and the other of said second pair of ports connected to the rod end of said air cylinder, a pressure port in said valve assembly connected directly into said jaw valve bore and directly into said cylinder lid valve bore intermediate the endsrthereof and directly into each end of said jaw valve bore, exhaust port means connected in o said jaw valve bore and said cylinder valve bore, a jaw valve spool slidably carried in said jaw valve bore, said jaw valve spool being formed so that when said jaw valve spooltis alternately moved between the ends of said jaw valve bore said first pair of ports connected into said jaw valve bore are alternately connected to said pressure port and said exhaust port means, a cylinder valve spool slidably carried in said cylinder valve bore, said cylinder valve spool being formed so that when said cylinder valve spool is alternately moved between the ends of said cylinder valve bore the second pair of ports connected into said cylinder valve bore are alternately connected to said pressure port and said exhaust port means, means at each end of said jaw valve bore for momentarily substantially reducing any air pressure thereat, and a pair of passageways formed in said valve assembly, each of said passageways defining an orifice therein, each of said pair of passageways connected between one of said first pair of ports and one end of said cylinder valve bore, said orifices being formed as a restricted opening sufiiciently small to provide a time delay between the application of any substantial pressure at said first pair of ports and the ends of said cylinder valve bore.

13. In a press feed mechanism as defined in claim 12, wherein said valve assembly comprises a central body portion having said jaw valve bore and said cylinder valve bore formed therethrough, and end plates secured to said body portion over the ends of said jaw valve bore and said cylinder valve bore, and said pair of passageways each comprise a recess formed in the surface of the side of said end plates which engages said central body portion, each of said recesses extending from one end of said cylinder valve bore to a passageway formed in said central body portion and connected to said first pair of ports, each of said recesses having at least one portion thereof of a cross sectional area such that said one portion defines an air restricting orifice in engagement with said central body portion.

14. In a feed mechanism as defined in claim 6, wherein said movable jaw comprises a base member journaled on said tubular members and an upper jaw portion fixedly carried on and a certain distance above said base member thereof, said upper jaw portion of said movable jaw extending upwardly from said channel members a height substantially equal to the corresponding height of said stationary jaw, said base member of said movable jaw comprising an air piston arrangement including a cavity so that the piston of said arrangement is moved upward responsive to air under pressure delivered to said cavity to clamp any stock positioned between said air piston arrangement and said upper jaw portion, and an air conduit journaled through said end plate between said channel members and above the plane of the underside of said channel members, one end of said air conduit being connected through said base member of said stationary jaw into free air communication with said cavity therein, the other end of said air conduit being adapted to receive air under pressure.

7 15. An air operated jaw for a feed mechanism comprising, a generally rectangularly shaped base member, means on said base member for supporting said base member in a feed mechanism, a rectangular cavity formed in the upper surface of said base member and extending longitudinally thereof with the upper marginal edges of said cavity spaced inwardly of the marginal edges of said upper surface, an air passageway formed through said base member and into said cavity for delivering air under pressure to said cavity, an elastorner sheet substantially covering said cavity and said upper surface, a rectangular plate having a substantially rectangular opening formed therethrough and extending longitudinally thereof, the length and width of said opening being greater than the respective length and width of said cavity at the upper marginal edges thereof, said rectangular plate positioned on said elastomer sheet with said opening being disposed concentrically above said cavity, means for securing said plate to said base member to seal said elastomer sheet about the upper marginal edges of said cavity, a substantially rectangularly shaped piston member having a length and width substantially equal to the respective length and width of said opening through said plate and having a thickness greater than the thickness of said plate, said piston member disposed in said opening through said plate to rest upon said elastomer sheet, and a jaw reaction member secured to said base member and extending over said piston member in a parallel spaced relationship thereto so that a material to be fed by said feed mechanism is insertable between said jaw reaction plate and said piston member.

16. In an air operated jaw for a feed mechanism as defined in claim 15, wherein said jaw reaction member is secured to said base member by a plurality of fasteners extending through one end of said jaw reaction member and into said base member, a plurality of shims carried between said jaw reaction member and said base member to selectively space said jaw reaction member from said piston member, the other end of said jaw reaction member extending over said piston member as a cantilever.

17. In an air operated jaw for a feed mechanism as defined in claim 15, wherein said means securing said plate to said base member comprises a plurality of fasteners journaled through said plate in a spaced apart relationship to each other about said opening and extending through said elastomer sheet and into said base member.

18. A stroke adjustment bar for adjustably limiting the stroke of a jaw which is movably carried on a pair of spaced apart, parallel, tubular members with said jaw being moved by a rod positioned between said tubular members and parallel thereto comprising, a generally rectangularly shaped bar member having a pair of spaced apart holes so that said bar member is mountable on said pair of tubular members, said bar member further having a third hole therethrough positioned to permit said rod for moving said jaw to be inserted therethrough, said bar member further being provided with a pair of slots, each of said slots formed through said bar member to intersect the side wall of one of said pair of holes on the side thereof toward the center of said bar member and to extend upwardly therefrom along an incline directed toward the center and to the upper surface of said bar member, and a pair of fasteners, each of said fasteners extending from the upper surface of said bar member through one of said slots and threaded into a portion of said bar member below said slots so that said slots are effectively closed to reduce the diameter of said pair of openings when said fasteners are securely threaded into said member.

19. A stroke adjustment bar as defined in claim 18, wherein said stroke adjustment bar comprises a Vernier stroke adjustment means, said Vernier stroke adjustment means comprising a bushing member threaded into said third hole of said bar member on the side thereof toward said jaw, said bushing member having an inner diameter greater than the diameter of said rod for moving said jaw, and a lock nut threaded on the outer surface of said bushing member for locking said bushing member in any selected threaded position in said bar member.

References Cited in the file of this patent UNITED STATES PATENTS 2,096,073 Spencer Oct. 19, 1937 2,291,999 Wilson et al Aug. 4, 1942 2,379,002 Haller June 26, 1945 2,576,114 Hibbard Nov. 27, 1951 2,622,874 Haller Dec. 23, 1952 2,657,046 Tallis Oct. 27, 1953 2,704,087 Lindsay Mar. 15, 1955 2,754,117 Ghormley July 10, 1956 2,842,284 Flick July 8, 1958 2,868,217 Faisandier Ian. 13, 1959 2,978,160 Bunnell Apr. 4, 1961 3,038,647 Grimm June 12, 1962 FOREIGN PATENTS 731,939 Great Britain June 15, 1955