US3473425A

US3473425A - Stamping apparatus

Info

Publication number: US3473425A
Authority: US
Inventors: Joseph E Foist; Chester J Matthews
Original assignee: Toledo Stamping and Manufacturing Co
Current assignee: Toledo Stamping and Manufacturing Co
Priority date: 1967-11-13
Filing date: 1967-11-13
Publication date: 1969-10-21
Anticipated expiration: 1986-10-21
Also published as: GB1245107A

Description

Oct. 21, 1969 J. E. FOIST ETAL STAMPING APPARATUS 2 SheetswShee Filed Nov. 13, 1967 1. exrorzs; JUSEPH L Furs T BY CHESTER J. JI/Lwmzws.

Get. 21, 1969 J. E. FOIST ETAL 3,473,425

STAMPING APPARATUS Filed NOV. 13, 1967 2 Sheets-Sheet /6 IXCENTORS:

United States Patent 3,473,425 STAMPING APPARATUS Joseph E. Foist and Chester .l. Matthews, Toledo, Ohio,

assignors to Toledo Stamping & Manufacturing Company, Toledo, Ohio, a corporation of Ohio Filed Nov. 13, 1967, Ser. No. 682,241 lint. Cl. 1323f 1/02; B23d 21/14 ILS. Cl. 83-129 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for producing an opening in a wall of a workpiece and including stripping means for holding the workpiece when the tool which forms the opening is retracted.

The invention is specifically designed for use with stamping apparatus for punching or piercing holes in stamped, boat-type rocker arms. Such rocker arms are discussed more fully in U.S. Patent Re. 24,941. In this type of rocker arm, the openings in the sidewalls through which the supporting shaft extends must be close to or partially contiguous with the bottom or transverse wall of the rocker arm, since a portion of this wall preferably forms a bearing surface for the shaft. Consequently, the openings in the sidewalls must be carefully formed to provide a smooth bearing surface with the bottom.

Because the tool or punch must form the opening contiguously with the bottom wall of the rocker arm, an additional supporting member engageable with the outer surface of the bottom wall must be employed to prevent the rocker arm from moving away from the punch as the punch moves toward and through the sidewall. This is especially necessary because a fillet is commonly formed between the bottom wall and the sidewall and the fillet otherwise tends to cam or force the bottom wall of the rocker arm away from the punch as the punch moves toward the sidewall and contacts the fillet. Movement of the supporting member also must be coordinated with the movement of the punch and this can be accomplished by a single drive arrangement.

In accordance with the invention, a unique stripper is employed with the stamping apparatus which holds the workpiece as the punch is retracted, with the stripper also actuated by the driving means for the punch. In a preferred form, a work-engaging unit which includes the stripper also carries the supporting member for the workpiece with the entire unit then moved by the drive means which operates the punch.

It is, therefore, a principal object of the invention to provide apparatus for forming openings in workpieces in combination with a stripper for automatically engaging the workpiece and holding it as the punch is retracted.

Another object of the invention is to provide apparatus for forming an opening in a sidewall of a rocker arm with a supporting member for the bottom wall of the rocker arm and a stripper moved in coordination with the holeforming punch.

Many other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawing, in which:

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FIG. 1 is a view in vertical cross section of apparatus for producing openings in sidewalls of a rocker arm;

FIG. 2 is a view similar to FIG. 1 but with the die units closed and with an opening being pierced;

FIG. 3 is a view taken along the line 33 of FIG. 2; and

FIG. 4 is a view in perspective of a rocker arm having sidewall openings formed with the apparatus of FIGS. 1-3.

Referring to the drawings, a die set indicated at 10 includes a lower die unit 12 and an upper driving unit 14. While the die set 10 is shown as having a single station, two stations can be employed to form openings in opposite sidewalls of two rocker arms at the same time. The lower die unit 12 includes a supporting table or base 16 on which are located a punch assembly 18, a back-up die 20, and a combination stripping and supporting or workengaging unit 22. The punch assembly 18 includes a base block 24 on which a punch arm 26 having a punch or tool 28 is located. The punch 28 can be a replacable, hardened steel insert, if desired, as is known in the art. The block 24 has a pair of spaced cylindrical recesses 30 which receive ends of coil springs 32 which are also held in cylindrical recesses 34 in the base 16. The base block 24 is guided for limited vertical movement by suitable means such as end guide blocks 36 (FIG. 3).

The back-up die 20 (FIG. 1) has a cylindrical insert 38 forming a passage 40 similar in shape and size to the opening to be formed in the rocker arm, with the slugs from the workpiece being disposed of through the passage 40.

The stripping and supporting unit 22 includes a camoperated slide 42 guided between ways 44 and 46 (FIG. 3) for movement toward and away from the punch assembly 18. A return spring 48 is located in a recess 50 in the base 16 and bears against a retaining plate 52 aflixed to a rear portion of the slide 42, with a pin 54 seated in the end of the spring 48. In accordance with the invention, a stripper arm 56 extends firwardly on the slide 42 and moves to a position over the workpiece when the slide is in a firs or forward position. The slide 42 also includes a supporting arm 58 which is slidably held in a recess 60 in the slide and is gunded for movement parallel to the movement of the slide by a slot 62 in the arm cooperating with a pin 64 in the slide body. Springs 66 urge the supporting arm 58 in a direction toward the workpiece.

The slide 42 is moved toward the workpiece by a cam member 68 forming part of the driving unit 14. The cam member 68 has a lower slanted camming surface 70 cooperating with a slanted camming surface 72 on a rear portion of the slide 42. When the cam member 68 is moved vertically downwardly, the surface 70 engages the surface 72 to move the slide 42 toward the left until the upper end of the surface 70 moves below the lower end of the surface 72, as shown in FIG. 2. With the slide 42 in this position, a stop bar 74 positioned adjacent the die 20 is received in a forward notch 76 of the slide 42 which aids in holding the slide 42 downwardly as the punch 28 is retracted.

The cam member 68 is mounted on a drive plate 78 which is guided in a vertical path by guide rods 80 and can be moved by any suitable means. A drive block 82 also is mounted on the plate 78 and engages the top of the punch arm 26 to move the punch 28 downwardly.

In the operation of the stamping apparatus, a workpiece shown in the form of a rocker arm blank 84 is placed with a sidewall 86 on the back-up die 20. An opening 88 (see FIG. 4) is to be formed in each of the sidewalls 86 of a finished rocker arm 90 when completed, with a substantial portion of the edge of the opening 88 constituting an extension of a bottom wall 92 of the rocker arm so that the inner surface of the bottom wall 92 and part of the edge of the opening 88 can constitute a bearing surface for a supporting shaft. As such, the opening 88 must be carefully formed contiguously with the inner surface of the bottom wall 92.

With the workpiece 84 placed on the back-up die 20 and over the punch 28 and punch arm 26, the end of the punch arm 26 being contoured to help position the workpiece, the driving unit 14 is moved downwardly. Initially, the cam 68 moves the slide 42 toward the left until the surface 7% moves downwardly below the surface 72 of the slide. During this movement, the supporting arm 58 engages the outer surface of the bottom wall 92 and holds it firmly against the punch arm 26 by virtue of the springs 66. The arm 58 thus prevents the punch 28 from pushing the bottom wall 92 outwardly as it engages the fillet usually existing between the bottom wall 92 and the sidewall 86. This assures that the opening 88 is formed close to the inner surface of the bottom wall 92. At the same time that the supporting arm 58 engages the wall 92, the stripper 56 moves above and contiguously with the upper sidewall 86 of the blank 84, as shown in FIG. 2. When the cam surface 68 moves to a point just below the surface 72, the block 82 will be adjacent but not yet engaged with the punch arm 26. However, in the next small increment of downward movement of the drive plate 78, the block 82 causes the arm 26 to move downwardly and causes the punch 28 to form the opening 88 in the sidewall 86. The slide 42 will remain stationary during this movement since it cannot move further toward the left due to the fact that only the vertical surfaces of the slide 42 and the cam 68 are now in contact.

When the plate 78 is raised, the punch 28 will first be retracted from the opening by virtue of the springs 32, during which time the stripper arm 56 will remain above the workpiece blank 84 to prevent movement thereof during the retraction of the punch. As the drive plate 78 is raised, and the vertical surfaces of the cam member 68 and the slide 42 move out of engagement, the spring 48 will cause the slide to move toward the right or retract, after which the workpiece can be removed and reversed on another station of the press, if desired, so that the second opening 88 can be formed in the other sidewall 86.

From the above,it will be seen that the apparatus according to the invention provides a quick and effective operation for punching the workpiece and an efficient arrangement for supporting the workpiece during punching and for stripping the punch. Further, the apparatus is relatively simple and maintenance free.

lMany modifications of the above described embodiment of the invention will be apparent to those skilled in the art, and it is to be understood that such modifications can be made without departing from the scope of the invention, if within the spirit and the tenor of the accompanying claims.

We claim:

1. Apparatus for producing an opening in a wall of a workpiece comprising a base, an arm supported by said base, a punch having a cross-sectional shape similar to that desired for said opening, said punch being functionally integral with said arm and movable with said arm in a direction transversely to a face of said punch, driving means for moving said punch, a backup die supported by said base and having an opening aligned with said punch, a workengaging unit, means for guiding said unit between a first position adjacent the workpiece and a-second position away from the workpiece in a direction transverse to the direction of movement of said punch, said work-engaging unit comprising a slide having a stripper arm positioned to prevent movement of said workpiece in a direction parallel to the direction of movement of said punch when said work-engaging unit is in the first position, and means movable in coordination with said driving means for moving said work-engaging unit from said second position to said first position.

2. Apparatus according to claim 1 characterized by a work supporting arm yieldably carried by said slide and positioned to resist movement of the workpiece in a direction transversely of the movement of said punch when said work-engaging unit is in the first position.

3. Apparatus according to claim 1 wherein said co ordinating means comprises a cam movable with said driving means and having a slanted end, said slide having a slanted surface cooperating with said slanted end to cause said slide to move toward the workpiece when engaged by the slanted end.

4. Apparatus according to claim 3 characterized by resilient means for returning said workpiece-engaging unit from the first position to the second position after being moved to said first position by said cam.

5. Apparatus for performing an operation on a workpiece comprising a driving member, a tool engageable by said driving member for movement toward the workpiece to perform a function thereon, a work-engaging unit, means for directing said unit between a first position adjacent the workpiece and a second position away from the workpiece in a direction transverse to the direction of movement of said too], said work-engaging unit comprising a slide having a stripper arm positioned to resist movement of said workpiece in a direction parallel to the direction of movement of said tool when said work-engaging unit is in the first position, and means movable in coordination with said driving means for moving said work-engaging unit from said second position to said first position.

6. Apparatus according to claim 5 characterized further by said workpiece having adjacent walls extending at an angle to one another with said tool engaging one of said walls adjacent the other one, said slide further having a work supporting arm contoured to engage the other wall to prevent said other wall from moving away from said tool when said tool engages the one wall.

7. Apparatus according to claim 5 characterized further by said slide having a recess, a work supporting arm in said recess, and spring means in said recess urging said work supporting arm toward the workpiece to resist movement of the workpiece in a direction transversely of the movement of said tool when said workengaging unit is in the first position.

8. Apparatus according to claim 5 characterized further by said coordinating means comprising a cam member extending outwardly from said driving means and having a slanted surface, and said slide having a slanted surface engageable with said cam surface to move said slide and said stripper arm toward the first position.

9. Apparatus according to claim 8 characterized further by a return spring for moving said slide from said first position to the second position when said slanted surfaces are out of engagement.

10. Apparatus according to claim 8 characterized further by said driving means having means engageable with said tool for moving said tool toward the workpiece after said cam has moved said slide to the first position.

References Cited UNITED STATES PATENTS 10/1910 Malton 83-135 V US. Cl. X.R. 83191