US3310973A

US3310973A - Stock pusher

Info

Publication number: US3310973A
Application number: US436796A
Authority: US
Inventors: Arthur F Leis
Original assignee: A F LEIS CO Inc
Current assignee: A F LEIS Co Inc
Priority date: 1965-03-03
Filing date: 1965-03-03
Publication date: 1967-03-28
Anticipated expiration: 1984-03-28

Description

3,31%,9'73 STOCK PUSHER Arthur F. Leis, A. F. Leis 60., line, 611 Ewing St, Dayton, @hio 454M- Filed Mar. 3, 1%5, Ser. No. 436,796 10 Claims. (Cl. 72-429) This invention relates to metal forming presses, and more particularly, to apparatus for properly aligning the workpiece in such presses.

When strip stock is fed through a die in a punch press or the like, it is necessary to position the stock against a reference surface prior to the punching operation in order to consistently produce finished products having the same dimension. The position of the hole or other metal forming operation in the workpiece is often very critical, especially when the finished parts are to be used in modern precision machinery or equipment of one type or another. Consequently, if the stock pusher does not operate effectively and the stock is not properly positioned in the dies, the result is a finished product which must be scrapped since it cannot meet the various quality control tests. It is difiicult to maintain the effective operation of the pusher plate or stock pusher since the various components of the metal working press take a severe pounding during the repeated high speed operation thereof.

Accordingly, it is an important object of the invention to provide an improved stock pusher for use in metal forming presses which can be adapted for use with most metal working presses and which will continue to operate effectively after a substantial period of use.

A further object of this invention is to provide a stock pusher of the aforesaid type which imparts a horizontal force to the pusher plate each time the die shoes are brought together, and particularly to provide such a stock pusher which does not impart vertical or transverse forces to the pusher plate so that it is not distorted or bent, even after long periods of use, thereby maintaining the effective operation thereof.

Another object of this invention is to provide a stock pusher of the aforesaid type with a novel actuator assembly adapted particularly for use with workpieces which must be inserted into a female cavity in the lower die shoe, and particularly to provide an improved stock pusher which provides for easy insertion of the workpiece into the cavity and which will precisely position this workpiece as the die shoes move together.

A further object of this invention is to provide improved stock pushers which are manufactured from sheet metal parts and consequently are inexpensive and light in weight, and further to provide such stock pushers which are simple in design and insensitive to wear for maximum dependability over long periods of time.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a side elevation view of a metal working die showing the improved stock pusher mounted thereon;

FIG. 2 is a sectional view through the metal working die with the stock pusher shown in its lowered position;

P16. 3 is an elevation view looking from left to right of FIG. 1;

FIG. 4 is a sectional view through another embodiment of the invention taken essentially along the line 4-4 of FIG. 7;

FIG. 5 is an elevation view similar to FIG. 1 and illustrating this second embodiment of the invention;

FIG. 6 is a view similar to FIG. 5 showing the stock pusher in its lowered position; and

Patented Mar. 28, 1967 FIG. 7 is a plan view of the pusher member used in the embodiment of FIG. 5.

Referring to the drawings wherein preferred embodiments of the invention are shown, FIGS. 1 and 2 illustrate portions of a metal working die 10 which comprises a stationary lower die shoe 11 having a lower die block 12 rigidly mounted thereon. The stripper plate 13 is mounted rigidly on the lower die block 12, and this plate has a cavity 15 in the lower surface 16 thereof which forms a passage through which the strip stock 20 passes in a conventional manner. The stripper plate 13 has a female die opening 21 therein for receiving the male punch 22 which removes a portion 24 (FIG. 2) of the strip stock 20, and this portion passes downwardly through the

female die openings

25 and 26 in the lower die shoe and die block 11 and 12.

Mounted above the lower die shoe 11 is an upper or movable punch holder 30 which is reciprocated in a conventional manner (not shown). The punch 22 is held rigidly and precisely in position on the upper punch holder 30 by a conventional punch retainer 32, and a feeding device (not shown) is provided for automatically advancing the metal stock 20 each time the upper punch holder 39 reciprocates so that the punch 22 removes the portion 24 of the metal stock 20 each time it reciprocates.

A rectangular pusher plate 33 is mounted in another slot 34 formed between the stripper plate 13 and the lower die block 12 so that the pusher plate 33 extends beyond the left-hand edge 35 of the stripper plate 13 and the inner end 36 thereof extends into the cavity 15 to engage the left-hand edge 37 of the metal stock '20. Movement of this pusher plate 33 is restricted by a guide pin 40 which is securely mounted in the stripper plate 13 and engages the elongated opening 41 in the plate 33 to enable this plate to reciprocate within limits toward and away from the metal stock 20. The pusher plate 33 thus applies pressure to the right-hand edge 37 of the metal stock 20 to force it against the right-hand or reference surface 43 of the cavity 15 in the stripper plate 13 so that the metal stock 20 is precisely positioned with respect to this surface each time the punch 22 engages the female opening 21.

An important part of the invention resides in the pusher assembly for reciprocating the pusher plate 33 in such a manner that no vertical or bending forces are applied to this plate, the stripper plate 33, or lower die block 12. This assembly includes an upper cam arm which is resiliently mounted on the bracket 51 secured to the upper punch holder 30 by the bolts 52, as seen in FIG. 3. This bracket has the side walls 54 thereon which limit the movement of the arm 50 to a direction parallel to these side walls.

The upper end portion of the arm 50 is secured in place by the elongated stud 55 which passes through a suitable opening 57 in the end wals 58 of the bracket and through the arm Stl. The right-hand end '61 of this stud is threaded and receives the nut 62 to limit leftward movement thereof, and the spring 63 is interposed between the nuts 64 and the Washer 65' on the left-hand end of the stud 55 and the arm 50, so that the arm is continuously urged against the end wall 58 and projects substantially vertically downward. Thus the upper cam arm 50 will pivot in a leftward direction against the bias of the spring 63 when the cam surface 66 on the lower end thereof engages the lower roller arm assembly 68, as will be seen.

The lower roller arm 68 is mounted on a bracket 70 which is substantially identical to the bracket 51 and thus has the side and

end walls

71 and 72, respectively, eX- tending upwardly therefrom. This bracket is held in position on the lower die shoe 11 by the bolts '74 in a conventional manner, and the arm '68 is generally U-shaped in horizontal cross-section and the lower end 9 thereof is pivotally secured to the bracket 70 by the pivot pin 75 which extends through the

opposite side walls

72 and 76 of the bracket and arm, respectively. The pin 75 is held in place by the snap rings 77 which engage suitable grooves in each end of the pin.

A coil spring 80 surrounds the pivot pin 75 between the side walls 76 of the arm and one end 81 of the spring engages the end wall 71 of the bracket 70, as seen in FIG. 2. The other end 02 of the spring engages the fiat base wall 84 on the arm 68 so that this arm is continually urged in a counterclockwise direction, as viewed in the drawings, to the position spaced from the pusher plate 35. The upper end of the roller arm 68 supports a cam roller 85 on the cross pin 86 which extends through the side walls 76 of the arm 68 and is held in place by the snap rings 87 in suitable grooves in the opposite ends of the pin 86.

In operation, each time the upper punch holder 30 moves the punch 22 downwardly, it also moves the upper cam arm 50 into engagement with the roller arm assembly 68 so that the cam surface 66 engages the roller 85. This action pivots the arm 58 in a clockwise direction so that the base wall 84 thereof engages the left-hand edge 35 of the pusher plate 33 and moves it to the right to urge the metal stock 20 against the reference surface 43 of the stripper plate 13.

As the upper arm 50 continues this downward movement, the metal stock 20 and pusher plate 33 terminate their rightward movement by reason of contact between the stock and the surface 4-3, and the arm 50 is allowed to pivot in a clockwise direction against the bias of the spring 63 to permit continued downward movement thereof. During this time, the upper cam arm 50 continually urges the lower cam arm 68 to the right to maintain a preset force on the metal stock 20 to hold it in place against the surface 43.

As the upper punch holder commences its upward movement, the upper cam arm 50 is withdrawn and the spring '63 returns it to its vertical position. Thereafter, the spring 30 returns the lower arm 60 to its inactive position spaced from the pusher plate 33, and this allows the metal stock 20 to be advanced through the press which usually causes the free floating pusher plate 33 to be shifted to the left. Each time the press operates, the operation described above is repeated so that the metal stock is always positioned accurately with respect to the reference surface 43 and thus properly aligned for the punching or other operation.

Another embodiment of the invention is shown in FIGS. 5-7 wherein the workpiece 100 is in the form of an individual blank of sheet metal rather than a strip of stock 20, as in the embodiment shown in FIGS. 1-3. Accordingly, the lower die shoe 12a has a female die 101 mounted thereon and adapted to have the metal blank 100 deformed downwardly to assume the shape of the depression 104 therein. The upper punch holder 300 has a punch 105 therein for accomplishing this forming operation, and the punch 106 is accordingly aligned with the depression 104 in a conventional manner. The vertical shoulder 108 provides a reference surface on the die 101 against which the blank 100 must be held in order to obtain the tolerances in the finished product.

The upper punch holder a has a stripper 110 thereon which consists of a vertical stud 111 rigidly secured to the upper punch holder 30a. This stud has an annular block 113 reciprocally mounted thereon by the coil spring 114 which surrounds the stud and permits vertical movement of the block 113 on the stud 111. Accordingly, each time the upper punch holder 30a moves downwardly, the block 113 engages the metal blank 100 to strip it from the punch 106 when the latter starts its upward movement.

A pusher assembly 115 is disposed adjacent the lefthand edge 116 of the workpiece 100 to urge it to the right against the reference surface 108, and this assembly includes a mounting bracket 118 which has the flanges 119 on the sides thereof through which the bolts 121 pass to secure the bracket rigidly to the lower die 101. This bracket has the side surfaces 122 extending upwardly from the flanges 119 with a top wall 123 extending between these side walls. The downwardly extending fingers 125 on opposite sides of the top wall 123 extend between the side walls 127 of the pusher body 130 thereby restricting movement of this body to the right and left, as viewed in FIGS. 4 and 7.

An elongated shouldered pin 132 is rigidly secured between the downwardly extending fingers 125, as seen in FIG. 4, and this pin passes through the vertical projection 131 which extends upwardly from the bottom wall of the pusher body 130. The pin 132 is slidably received in the projection 134 so that the pusher body 130 reciprocates along the horizontal surface 137 of the lower die 101. A coil spring 140 is interposed between the lefthand finger 125 on the bracket 118 and the projection 134 on the pusher body 130 to urge continually the pusher body to the left, as viewed in FIG. 5.

The end edges 142 of the side walls 137 of the pusher body 130 are tapered to facilitate insertion of the metal blank or workpiece 100 into the die 101 whereas the lower portion 144 of these side walls and the bottom wall 135 are square so that the edge 116 of the workpiece 100 is securely engaged by the pusher body and forced against the reference surface 108. The upper cam arm 50 and lower roller arm 68 are identical to those described above, and accordingly the components of these arms are given identical reference characters.

In operation, a single blank 100 is inserted into the lower die 101, and the proper alignment is facilitated by the tapered surfaces 142 on the end edges of the pusher body 130. As the upper punch holder 30a commences its downward movement, the cam arm 50 engages the lower arm 68 causing the latter to pivot in a clockwise direction into engagement with the reciprocable pusher body 130. As the base wall 84 of the roller arm 68 contacts the right hand end of the pusher body 130, the pusher body commences movement to the right against the bias of the coil spring 140. Since the lower portion 144 of the right-hand edges of the pusher body are square and snugly engage the edge 116 of the metal blank 100, it forces the same against the reference shoulder 108.

Additional movement of the arm 68 and pusher body 130, and workpiece 100 is thereafter necessarily prohibited. As the upper arm 50 continues its downward movement, it moves against the bias of the spring 63 in a clockwise direction to terminate movement of the roller arm 68 while continuing to apply a predetermined pressure thereto. Thus, the workpiece 100 is precisely positioned with respect to the reference surface 108 so that the male die 106 engages the workpiece 100 and deforms the same into the depression 104 in a conventional manner thereby enabling the finished products to be formed to high tolerances.

The pusher assembly 115 can also be mounted on the die block 101 in a position from the position shown in the drawings and described above. In this position, the pusher body 130 is urged toward the reference surface 108 by the spring 140, and consequently, as the metal blank 100 is inserted into the die block 101 and forced downwardly it rides along the tapered surface 142a thereby camming the pusher body 12 to the left, as viewed in FIG. 4. When the metal blank is in position it is engaged by the lower edge 144a and is held firmly against the reference surface by the bias of the spring 140. In this arrangement, the upper and

lower arms

50 and 68 are not required since the pusher assembly 115 holds the workpiece 100 firmly in position.

While the embodiment shown in FIGS. 4-7 is described in connection with a metal forming operation, it should be understood that it can also be used in blanking and piercing operations to hold an individual workpiece in position. Moreover, the embodiment shown in FIGS. 1-3 can also be used in blanking and forming operations rather than strictly for piercing as shown and described.

The invention has thus provided an improved apparatus for positioning the workpieces and metal forming presses, so that the workpiece is precisely positioned each time the press is operated even after a considerable period of use. No vertical forces are applied to the pusher plate 33 or pusher body 136, so that these members are not deformed in any way to inhibit proper operation of the invention. Moreover, a majority of the major parts of the mechanism are made from sheet metal thereby decreasing the manufacturing and shipping cost thereof and the mechanism is easily installed in existing metal forming dies. The contact between the upper and

lower arms

50 and 61 is such that a slight amount of wear therebetween will in no way effect the movement of the pusher plate or bodies which have only horizontal forces applied thereto.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invenion is not limited to these precise forms of apparatus and that changes may be made therein without departing from the soipe of the invention which is defined in the appended claims.

What is claimed is:

1. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the metal stock is urged by a pusher plate for proper alignment in the die shoes, said stock pusher comprising a first arm member mounted on said stationary die shoe and having a contact surface for engaging the pusher plate to urge the metal stock toward the reference surface, said first arm member having a pivot connection on said stationary die shoe for pivotal movement about an axis spaced below the pusher plate so that said contact surface engages the pusher plate generally perpendicular to the plane of said pusher plate, a spring biasing said first member away from engagement with the pusher plate, a second arm member mounted on said movable die shoe for engaging said first member to move the said first arm member against the bias of said spring into engagement with the pusher plate, and spring means on said second arm member which allows said second member to apply only a preset force to said first arm member and the pusher plate to urge the metal against the reference surface.

2. A stock pusher of the character described adapted to be mounted on a metal forming press which includes upper and lower die shoes, one of the die shoes including a reference surface against which the metal stock is urged by a pusher plate for proper alignment in the die shoes, said stock pusher comprising -a first arm member mounted on said one die shoe and having a contact surface for engaging the pusher plate to urge the metal stock toward the reference surface, said first arm member having a pivot connection on said one die shoe for pivotal movement about an axis spaced parallel to and from the pusher plate so that said contact surface engages the pusher plate perpendicularly to the plane of said pusher plate, a spring biasing said first arm member away from engagement with the pusher plate, a second :arm member mounted on the other of said die shoes for engaging said first arm member to move the said first arm member against the bias of said spring into engagement with the pusher plate, and relisient means associated with said second arm member to allow said second arm member to apply only a preset force to said first arm member and the pusher plate to urge the metal against the reference surface.

3. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the metal stock is urged by a pusher plate for proper alignment in the die shoes, said stock pusher comprising a first arm member mounted on said stationary die shoe and having a contact surface for engaging the pusher plate to urge the metal stock toward the reference surface, said first arm member having a pivot connection on said stationary die for pivotal movement about an axis spaced below the pusher plate so that said contact surface engages the pusher plate perpendicularly to the plane of said pusher plate, a spring biasing said first member away from engagement with the pusher plate, and a second arm member mounted on said movable die shoe for engaging said first member to move the said first arm member against the bias of said spring into engagement with the pusher plate to apply a preset force to said first arm member and the pusher plate to urge the metal against the refer ence surface.

4. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the metal stock is urged by a pusher plate for proper alignment in the die shoes, said stock pusher comprising a first arm member mounted on said stationary die shoe and having a contact surface for engaging the pusher plate to urge the metal stock toward the reference surface, said first arm member having a pivot connection on said stationary die for pivotal movement about an axis spaced below the pusher plate so that said contact surface engages the pusher plate perpendicularly to the plane of said pusher plate, a cam follower in the upper end of said first arm member, means biasing said first arm member away from engagement with the pusher plate, a second arm member mounted on said movable die shoe and having a cam surface on the lower end thereof for engaging said cam follower on said first arm member to move the said first arm member against the bias of said spring into engagement with the pusher plate, and means on said second arm member which allows said member to apply only a preset force to said first arm member and the pusher plate to urge the metal against the reference surface.

5. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the workpiece is urged, comprising means for properly aligning the workpiece in said die shoe, pusher means for engaging the workpiece to urge it against the reference surface, a first arm member mounted on said stationary die shoe and having a contact surface for moving said pusher means to urge the workpiece toward the reference surface, said first arm member having a pivot connection on the stationary die shoe for pivotal movement about an axis spaced below said pusher means so that said contact surface will engage said pusher means, a spring biasing said first arm member away from engagement with said pusher means, a second arm member mounted on said movable die shoe for engaging said first member to move the said first arm member against the bias of said spring into engagement with said pusher means, and resilient means on said second arm member which allows said second arm member to apply a preset maximum force to said first arm member and said pusher means to urge the workpiece against the reference surface.

6. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the workpiece is urged, comprising pusher means for engaging the workpiece to urge it against the reference surface, a first arm member mounted on said stationary die shoe and having a contact surface for moving said pusher means to urge the workpiece toward the reference surface, said first arm member having a pivot connection on the stationary die shoe for pivotal movement about an axis spaced below said pusher means so that said contact surface will engage said pusher means, biasing means urging said first arm member away from engagement with said pusher means, a second arm member mounted on said movable die shoe for engaging said first member to move the said first arm member against the bias of said biasing means into engagement with said pusher means, and resilient means on said second arm member which allows said second arm member to apply a force which does not exceed a preset maximum force to said first arm member and said pusher means to urge the workpiece against the reference surface.

7. A stock pusher of the character described adapted to be mounted on a metal forming press which includes a pair of stationary die shoes adapted for movement toward and away from each other, one of the die shoes including a reference surface against which the workpiece is urged, comprising pusher means for engaging the workpiece to urge it against the reference surface, a first arm member mounted on said one die shoe and having a contact surface for moving said pusher means to urge the workpiece against the reference surface without imparting bending forces to said pusher means, said first arm member having a pivot connection on the one die shoe for pivotal movement about an axis spaced below said pusher means so that said contact surface will engage said pusher means, a spring biasing said first arm member away from engagement with said pusher means, and a second arm member mounted on the other of the die shoes for engaging said first member to move the said first arm member against the bias of said spring into engagement with said pusher means to move the workpiece against the reference surface.

8. A stock pusher of the character described adapted to be mounted on a metal forming press which includes stationary and movable die shoes, the stationary die shoe including a reference surface against which the workpiece is urged, comprising pusher means reciprocably mounted on the stationary die shoe and adapted to engage the workpiece to urge it against the reference surface, means normally urging said pusher means away from contact with the workpiece, a first arm member mounted on said stationary die shoe and having a contact surface for moving said pusher means toward the workpiece, said first arm member having a pivot connection on the stationary die shoe for pivotal movement about an axis spaced below said pusher means so that said contact surface will engage said pusher means, means biasing said first arm member away from the workpiece, a second arm member mounted on said movable die shoe for engaging said first member to move the said first arm member into engagement with said pusher means, and resilient means on said second arm member which allows said second arm member to apply a preset maximum force to said first arm member and said pusher means to urge the metal against the reference surface.

9. Apparatus as defined in claim 8 wherein the said upper end of said first arm member has a cam roller thereon and the lower end of said second arm member has a cam surface thereon for frictionless engagement between said arm members.

10. A stock pusher of the character described adapted to be mounted on a die shoe of a metal forming press or the like, the die shoe including a reference surface against which the workpiece is placed for alignment, comprising a pusher assembly adapted to be mounted in two positions on the die shoe, said pusher assembly including a mounting bracket and a pusher body mounted on said bracket for reciprocation toward and away from the reference surface, spring means interposed between said bracket and said pusher body to urge said body in a first direction, and means for securing said bracket to the die shoe in a first position wherein said one direction is toward the reference surface so that said pusher body engages the metal blank to urge it against the reference surface and in a second position wherein said pusher body is urged away from the reference surface so that said pusher body contacts the metal blank only when force is applied to the opposite end thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,372,499 3/ 1945 Kerner 83-467 2,964,004 12/1960 Carper 83-451 WILLIAM W. DYER, JR., Primary Examiner.

G. A. DOST, Assistant Examiner.