US3400838A

US3400838A - Stock pusher

Info

Publication number: US3400838A
Application number: US493441A
Authority: US
Inventors: Arthur F Leis; Charles A Leis
Original assignee: A F LEIS CO Inc
Current assignee: A F LEIS Co Inc
Priority date: 1965-10-06
Filing date: 1965-10-06
Publication date: 1968-09-10
Anticipated expiration: 1985-09-10

Description

p 1968 A. F. LEIS ETAL 3,400,838

STOCK PUSHER Filed Oct. 6, 1965 FIG-1 ig- 3o xylza INVENTORS m0 ARTHUR F. LEIS a CHARLES A.LE|$ 107. a

I ATTORNEYS 3,400,838 STOCK PUSHER Arthur F. Leis and Charles A. Leis, both A. F. Leis (30., Inc., 611 Ewing St., Dayton, Ohio 45404 Filed Oct. 6, 1965, Ser. No. 493,441 4 Claims. (Cl. 214--1.3)

ABSTRACT OF THE DISCLOSURE A stock pusher for urging stock in a metal forming press toward a reference surface so that close tolerances are maintained in the finished product. The stock pusher includes a pivotal arm supported by a bracket directly on the stripper plate and an arm mounted on the movable die shoe for engaging a cam roller on the pivotal arm to apply a force perpendicular to the edge of the pusher plate.

This invention relates to metal forming presses, and more particularly, to apparatus for properly aligning the workpiece in such presses. Reference is made to the co pending US. application of Arthur F. Leis, Ser. No. 436,796, filed Mar. 3, 1965, now Patent No. 3,310,973.

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 precise dimensions. The position of the hole, metal cut or deformation 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 positioning apparatus 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. Moreover, 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 an im proved 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 which is mounted on the stripper plate and this does not require mounting on lower die shoe thereby increasing the space available on the die shoe for the die block itself.

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 press showing the stock pusher of the invention mounted thereon;

- United States Patent FIG. 2 is a sectional view through the metal working press with the stock pusher shown in its engaged position;

FIG. 3 is a top view of the lower arm assembly of the stock pusher;

FIG. 4 is a bottom view of the upper section of the stock pusher;

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

FIG. 6 is a plan view of the lower arm assembly shown in FIG. 5.

Referring to the drawings wherein preferred embodiments of the invention are shown, FIGS. 1 and 2 illustrate portions of a metal working press or die 10 which comprises a stationary lower die shoe 111 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 slug 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 i2.

Mounted above the lower die shoe 11 is an upper die shoe 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 31. A feeding device (not shown) is provided for automatically advancing the metal stock 20 each time the upper punch holder 30 reciprocates so that the punch 22 removes the portion 24 of the metal stock 20 each time it reciprocates.

A rectangular pusher plate 32 is mounted in another slot 34 formed between the stripper plate 13 and the lower die block 12 so that the left edge 33 of the pusher plate 32 extends beyond the left-hand sides 35 of the stripper plate 13 and lower die block 12, and the inner end 36 of the plate 32 extends into the cavity 15 to engage the lefthand edge 37 of the metal stock 2i). Movement of this pusher plate 32 is restricted by a guide pin 40 which is securely mounted in the stripper plate 13 and engages the elongated slot 41 in the plate 32 to enable this plate to reciprocate within limits toward and away from the metal stock 2%. The pusher plate 32 thus applies pressure to the left-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 32 in such a manner that no vertical or bending forces are applied to this plate, the stripper plate 13 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 which extend through the flange portions 53, as seen in FIG. 4. These flange portions 53 have a downwardly extending center wall 54 with the side walls 55 on either side thereof, and a U- shaped guide 56 is secured to the wall for limiting the movement of the arm 50 to a direction parallel to these side walls.

The upper portion of the arm 50 is secured in place by the elongated stud 60 which passes through suitable'

openings

61 and 62 in the wall 54 and the guide 56 of the bracket and through the arm 50. Both

ends

64 and 65 of the stud 60 are threaded and the right-hand end 64 receives the nut 66 to limit leftward movement thereof, and the spring 68 is interposed between the nuts 70 and the washer 71 on the left-hand end of the stud 60 and the arm so that the arm is continuously urged toward the center wall 54 and projects substantially vertically downward. Thus the upper cam arm 50 will pivot in a leftward direction against the bias of the spring 68 when the cam surface 73 on the lower end thereof is forced to the left.

The lower roller arm 75 is mounted on a bracket 76 which is mounted directly on the stripper plate 13 and has the base 77 (F183) secured by the bolts 78 to the plate 13. The side walls 81 extend upwardly from the base 77 and to the left thereof, as seen in FIGS. 1 and 2, so that the end portions 82 thereof project beyond the side walls 35 of the stripper plate 13 and die blocks 12. The upper end 85 of the arm 75 is pivotally secured to the bracket 76 by the pivot pin 86 which extends through the opposite side walls 87 of the arm 75 and the end portions 82 of the bracket 76, and the pin 86 is held in place by the snap rings 88 which engage suitable grooves in each end of the pin. The extension 89 on one of the end portions 82 limits the clockwise movement of the arm 75 by contact with the base plate 77.

A coil spring 90 surrounds the pivot pin 86 between the side walls 87 of the arm 75 and one end 91 of the spring engages the base wall 77 of the bracket 76, as seen in FIG. 2. The other end 92 of the spring engages the flat base wall 93 on the arm 75 so that this arm is continually urged in a clockwise direction, as viewed in the drawings, to the inactive position (FIG. 1) spaced from the pusher plate 32. The lower portion of the roller arm 75 supports a cam roller 95 on the cross pin 96 which extends through the side walls 87 of the arm 75 and is held in place by the snap rings 97 in suitable grooves in the opposite ends of the pin 96 for free rotation of the cam roller 95.

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 lower roller arm 75 so that the cam surface 73 engages the roller 95. This action pivots the arm 75 in a counterclockwise direction so that the base wall 93 thereof engages the lefthand edge 33 of the pusher plate 32 and moves it to the right to force 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 32 terminate their rightward movement by reason of contact between the stock and the surface 43, and the arm 50 is allowed to pivot in a clockwise direction against the bias of the spring 68 to permit continued downward movement thereof. During this time, the upper cam arm 50 continually urges the lower cam arm 75 to the right to maintain a preset force on the plate 32 and the metal stock 20 to hold it in place against the surface 43.

As the upper punch holder 30 commences its upward movement, the upper cam arm 50 is withdrawn and the spring '68 returns it to its vertical position. Thereafter, the spring 90 returns the lower arm 75 to its inactive position spaced from the pusher plate 32, and this allows the metal stock 20 to be advanced through the press 10 which usually causes the free floating pusher plate 32 to be shifted to the left. Each time the press operates, the operation described above is repeated so that the metal stock 20 is always positioned accurately with respect to the reference surface 43 and thus properly aligned for the punching or other operation, but freed of any restraint between operations for easy advancement of the metal stock.

Another embodiment of the invention is shown in FIGS. 5 and 6 wherein the lower cam assembly 100 is mounted directly on the pusher plate 101 and does not require mounting on the die block 12a, die shoes 11a, or stripper plate 13a. Specifically, the rectangular pusher plate 101 is reciprocally mounted in a slot 102 formed in the stripper plate 13a in substantially the same manner as described above. An elongated opening 103 is provided in the stripper plate with the pin 104 extending through the stripper plate 13a and into this opening to limit the movement of the plate 101 from right to left, as viewed in FIGS. 5 and 6.

The left-hand end 105 of the pusher plate 101 has an extension 106 thereon which projects beyond the side walls 107 of the stripper plate 13a and the die block 12a, as seen in FIG. 5. This extension has a U-shapedmember 110 rigidly secured on the end thereof with the cam roller 111 mounted between the ends 112 of the member 110 by the shaft 113 which is held in place by the snap rings 115. Two coil springs 116 are mounted between the shoulder 117 of the member and-the stripper plate 13a to urge the member and the roller 111 to the left. It is also possible to use one spring which surrounds the extension 106.

The upper arm assembly 50 is identical to that described above and operates in substantially the same man ner. Thus, when the arm 50 moves downwardly, the cam surface 73 thereon engages the cam roller 111 and forces it together with the pusher plate'101 to the left against the bias of the springs 116. The pusher plate 101 thus urges the metal stock 20a against the reference surface 43a in the stripper plate 13a at which point further movement of the pusher plate 101 to the right is prohibited.

As the arm 50 continues its downward movement, it is allowed to pivot in a clockwise direction, as viewed in FIG. 5, against the bias of the spring 68, as described above. The spring 68 is much stronger than the biasing effect of the springs 116 acting on the lower cam assembly 100, and thus the pusher plate 101 and the metal stock 20a are held securely against the reference surface. As the upper die shoe 30a moves upwardly, the arm 50 disengages the cam roller 111 and the springs 116 return the pusher plate 101 to its inactive position spaced from the metal stock 20a thereby allowing the stock to be advanced. Each time the upper die shoe moves downwardly this operation is repeated and consequently the stock is always properly aligned with the punch 22.

While the embodiments described above are in connection with a metal punching operation, it should be understood that it can also be used with machines for performing blanking, piercing and other metal cutting and forming operations. In addition, both the upper and lower die shoes may be reciprocable, and it is possible to use the stock pushers to apply pressure directly to the metal. Moreover, the stock pusher may be mounted for use with stock in a pusher plate which lie in planes other than horizontal as shown.

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 so that these members are not deformed in any way to inhibit proper operation of the invention. The stock pushers are mounted independently of the lower die shoe and die block thereby decreasing the space required and adapting the stock pusher for use on a wider variety of metal working machines. Moreover, a majority of the major parts of the mechanism are made from sheet metal thereby decreasing the manufacturing and shipping costs thereof and the mechanism is easily installed in existing metal forming dies.

While the forms of apparatus herein described consitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is refined 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, a stripper plate cooperating with said stationary die shoes to define a passage through which metal stock passes through the die shoe, the stripper plate having 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 actuator member having a U-shaped metal bracket secured rigidly to said stripper plate independently of said stationary die shoe and having a pair of support ears projecting above said stripper plate and beyond one edge of the stripper plate, a U-shaped pivot arm mounted on and depending downwardly from said support ears of said bracket having a contact surface adapted to be moved to an active position in engagement with one edge of the pusher plate to urge the metal stock toward the reference surface, a pivot pin interconnecting said support ears of said bracket and said U-shaped pivot arm for movement of said arm toward and away from said active position, said pivot arm having its axis disposed substantially directly above said one edge, spring means surrounding said pivot pin and urging said actuator arm away from said pusher plate, said contact surface engaging the pusher plate generally perpendicular to the plane of said pusher plate to eliminate binding forces from said pusher plate, a cam roller rotatably mounted on said U-shaped pivot arm opposite said pusher plate, an arm member mounted on said movable die shoe for engaging said cam roller to move the said U-shaped pivot arm against the bias of said spring means into engagement with the pusher plate, and biasing means on said arm member which allows said arm member 6 to apply only a preset force to said first actuator member and the pusher plate to urge the metal stock against the reference surface.

2. A stock pusher as defined in claim 1 wherein stop means are provided on said pivot arm for engaging said bracket to limit movement of said pivot arm away from said stripper plate.

3. A stock pusher as defined in claim 2 wherein said contact surface on said pivot arm is flat for engaging said one edge of said pusher plate.

4. A stock pusher as defined in claim 1 wherein a said biasing means includes a spring which allows said actuator arm to pivot away from said pivot arm when said pivot arm pivots away from said active position wherein it applies only a preset force to said pusher plate.

References Cited UNITED STATES PATENTS 1,570,928 1/1926 Thomas 214-1.3 X 2,372,499 3/1945 Kerner 83467 X 2,629,443 2/1953 Girardello 83-387 X 2,964,004 12/1960 Carper 83-419 X 3,310,973 3/1967 Leis 83-419 X ROBERT G. SHERIDAN, Primary Examiner. F. E. WERNER, Assistant Examiner.