US3871254A

US3871254A - Means for piercing and stripping thick material

Info

Publication number: US3871254A
Application number: US350789A
Authority: US
Inventors: Jr Lawrence V Whistler; Iii Lawrence V Whistler; Harold J Whistler
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-04-13
Filing date: 1973-04-13
Publication date: 1975-03-18
Anticipated expiration: 1992-03-18
Also published as: JPS49130586A; BR7306535D0; DE2345513A1

Abstract

Means for piercing and stripping various kinds of material, comprising, a punch retaining means, a punch for piercing the material, means securing the punch to the punch retaining means, and a resiliently yieldable stripping means operatively connected with the punch to strip the pierced material from the punch and connected with the punch so that forces imposed on the punch when the punch pierces through the material are absorbed by the stripping means, and so that the stripping means reacts between the punch and the pierced material to strip the material from the punch and the stripping force is thus transferred via the stripping means directly to the punch to protect the means securing the punch to the punch retaining means.

Description

i United States Patent Whistler, Jr. et al.

MEANS FOR PIERCING AND STRIPPING THICK MATERIAL Inventors: Lawrence V. Whistler, Jr., 251

Doncaster Rd.; Lawrence V. Whistler, III, 368 Argonne Dr., both of Kenmore, NY. 14217; .Harold J. Whistler, 22 Highland Dr., Williamsville, NY. 14221 Filed: Apr. 13, 1973 Appl. No.: 350,789

US. Cl. 83/139, 83/140 Int. Cl B2ld 45/00, B26f 1/02 Field of Search 83/139, 138, 140; 279/30 References Cited UNITED STATES PATENTS Primary Exaininer-Donald R. Schran Attorney, Agent, or FirmShoemaker and Mattare ABSTRACT Means for piercing and stripping various kinds of material, comprising, a punch retaining means, a punch for piercing the material, means securing the punch to the punch retaining means, and a resiliently yieldable stripping means operatively connected with the punch to strip the pierced material from the punch and connected with the punch so that forces imposed on the punch when the punch pierces through the material are absorbed by the stripping means, and so that the stripping means reacts between the punch and the pierced material to strip the material from the punch and the stripping force is thus transferred via the stripping means directly to the punch to protectthe means securing the punch to the punch retaining means.

9 Claims, 10 Drawing Figures PATENTEDHAR I 81915 SHEET 1 0F 2 PATENTEDHARWQYS 3,871,254

SHEET 2 0F 2 FIG. 7.

MEANS FOR PIERCING AND STRIPPING THICK MATERIAL BACKGROUND OF THE INVENTION In conventional piercing and stripping means, when relatively heavy gauge stock or material is punched or pierced, failure of the means holding the punch to the punch retaining means is frequently experienced, since as the punch is pushed through the material, it reaches a point where the punch bursts" through the material, and'thesudde'n release of the punch pressure results in substantially an explosion type effect or load on the punch. Further, in conventional punch means, the stripper for stripping the pierced material from the punch is engaged between the punch retaining means and the pierced material; and accordingly, there is a tendency for the stripper to pull the punch from the punch retaining means when the pierced material is stripped from the punch.

In the present invention, the stripping means is engaged between the workpiece or material to be pierced and a head or shoulder means on the punch, so that as the punch passes through the workpiece, the shock load resulting from the bursting or explosive effect obtained as the punch breaks through the workpiece is absorbed by the stripping means and is not transmitted to the means retaining the punch to the punch shoe or punch retainer. Further, when the stripping means strips the pierced workpiece from the punch, the stripping force is transferred completely to the punch and not to the punch retaining means; and accordingly, there is no tendency for the stripper to pull the punch from the punch retaining means as in conventional devices. I

According to the invention, the stripper means may comprise an elastomer material such as rubber or polyurethane or the like, or a spring means, but it has been found that polyurethane works exceptionally well and is superior to rubber or the like.

OBJECT OF THE INVENTION It is an object of the invention to .provide a punch means and stripping means for piercing heavy gauge stock or material wherein the stripper means is engaged I against a shoulder on the punch itself and against the stock or material so that as the punch bursts" through the workpiece, the explosive force which results is absorbed by the stripper means, and the force exerted in stripping the pierced workpiece from the punch is transmitted to the punch itself and not the punch retaining means, to thus protect the means securing the punch to the punch retaining means.

BRIEF DESCRIPTION OF THE DRAWINGS 'FIG. 1 is a sectional view in elevation of a first form of the invention shown in position immediately prior to engagement with a workpiece.

FIG. 2 is a view similar to FIG. 1 showing the punch pushed through the workpiece and with the stripper means in compressed condition.

FIG. 3 is a view in section taken along line 33 of FIG. 2.

FIG. 4 is an exploded perspective view of the punch and stripper means of the present invention.

. the punch.

FIG. 7 is a view similar to FIG. 6 with the punch pushed through the workpiece. v

FIG. 8 is a' view in section taken along line 8-8 in FIG. 6, and

FIG. 9 is a plan view of the snap ring against which the stripper means of FIGS. 6 and 7 abuts.

DETAILED DESCRIPTION OF THE INVENTION In the drawings, wherein like reference numerals indicate like parts throughout the several views, a punch and stripper means according to the invention are indicated generally at 10 and comprise a punch shoe 11 to which a punch retainer 12 is suitably'secured in a conventional manner. The punch retainer has a socket 13 therein defining an axially, downwardly presented shoulder or surface 14. An elongate solid punch 15 having a body portion 16, a diametrically enlarged head portion 17 and a reduced diameter, elongated piercing point or punch point 18 thereon is secured to the punch retainer at the head 17 thereof with the head received in the recess 13 and against the surface 14. The punch is secured in the recess by means of a set screw or plurality of set screws 19 extended at an angle through the punch retainer and into engagement with the outer surface of the head portion 17 of the punch 15. A shallow, concave annular groove 20 is in the punch between the body portion 16 and head portion 17 thereof and defines an annular, axially downwardly presented shoulder 20'. An elongate, cylindrical, elas tomer stripper 21 of a suitable material such as rubber, polyurethane, or thelike, is fitted over the body portion 16 and in its normal, expanded condition, extends the length of the body portion 16 and punch point 18. The stripper 21 has a lower annular cap 22 of a suitable rigid material such as fiber or steel or the like, the cap 22 having an annular upstanding rim or flange 23 thereon with a radially inwardly directed rib or lip 24 engaged against the lower outer surface of the stripper 21 to maintain the cap 22 in position. A similar cap or cap means 25 is similarly secured to the upper end of stripper 21 and the stripper is secured to the punch by means of a set screw or plurality of set screws 26 extended radially through the upper cap 25 into engagement with the annular groove 20 in the punch. The upper inner marginal portion of upper cap 25 is engaged against the shoulder 20' on the underside of head 17 on the punch 15.

A workpiece W is supported immediately beneath the punch and stripper in a conventional manner and on top of a die bushing 27 which is held to a die retainer (not shown) in a conventional manner, the die retainer in turn being supported on a die shoe (not shown) in a conventional manner.

As seen in FIG. 2, the punch 15 has been pushed through the workpiece, and a slug S of the workpiece is separated from the workpiece and is falling away I therefrom. The sudden release of the load on the punch as the punch breaks or bursts through the workpiece and the explosive effect thus produced are absorbed by the stripper, which is in compressed condition at this stage of operation and acts in the nature of a shock absorber. Thus, the set screws 19 which retain the punch 15 to the punch retainer 12 are protected; and they are not sheared as frequently occurs in conventional punch and stripper means when a heavy workpiece is pierced, and wherein the stripping load is imposed on the lower face of the punch retainer;

Thus, with the arrangement according to the invention, all of the force resulting from the punch breaking through the workpiece W, and from stripping the pierced workpiece from the punch, is transferred through the stripper to the shoulder and thus directly to the punch and not to the punch retaining means as occurs in conventional devices.

In FIGS. 5 and 5a, a slightly modified form of the invention is illustrated, wherein rather than the set screws 19, a ball lock mechanism 28 is utilized to secure the punch in position relative to the punch retainer 12. The ball lock 28 includes an inclined cavity or bore 29 in the punch retaining means 12 in which is fitted a ball 30 and coil spring 31 for urging the ball downwardly in the bore 29. A shallowdepression of substantially tear drop shape 32 is in the outer side surface of the head 17 of punch 15' and the ball 30 is engaged in this depression 32 to securely lock the punch in retainer 12. The upper end of the head 17 of the punch 15' is engaged against a back up plate supported on the punch shoe in a conventional manner. In all other respects this form of the invention is identical to the form of the invention illustrated and described with reference to FIGS. 1 through 4.

In FIGS. 6 through 9, a further modified punch and stripper means 10" comprises an elongate solid punch 34 having a body portion 16' and a reduced diameter punch end or piercing point 18 and an annular channel or groove 35 adjacent an upper end portion of the body portion 16'. An annular channel or groove 36 is in the punch at the upper end of the body portion and defines an axially, downwardly facing shoulder 37. The punch 34 has a head portion 38 of substantially the same diameter as the body portion 16', with the head 38 secured in punch retainer 12 by means of a

ball lock

30, 3l, 32 as in the previously described embodiment, and with the upper end of the head 38 engaged against the underside of the back up plate 33 suitably secured to the punch shoe 11.

A snap ring 39 is fitted within the channel 36 between the body portion 16 and head 38 of punch 34, in spaced relation to the punch retaining means 12, and a modified stripper means 40 is operatively connected with the punch 34 and is engaged against the underside of snap ring 39. The modified stripper means 40 includes an annular collar or cap means 41 secured to the upper end portion of the body portion 16 by means-of a plurality of radially extending set screws 19 extended through the collar 41 and into the groove 35 in the body portion 16 of the punch 34.

A plurality of spaced apart bores 42 extend from the upper surface of the collar 41 toward the lower surface thereof and a plurality of guide pins 43 are slidably positioned in the bores 42, and each has an enlarged head 44 thereon which engages against the bottom of the bore 42 of collar 41. The guide pins 43 have threaded lower ends 45 threadably engaged in spaced apart threaded bores in a'workpiece engaging annular plate or collar 46. A coil spring 47 surrounds each guide pin 43 and is engaged at its lower end with the upper surface of the plate 46 and is engaged at its upper end with the undersurface of collar 41 forurging the plate 4 downwardly relative to the punch 34.

The workpiece W is supported in a conventional manner on top of a die bushing 27 which is in turn supported in a die retainer 48 which is suitably supported in a conventional manner on a die shoe 49.

As seen in FIG. 6, the punch is shown in position about to engage the workpiece W with the springs 47 in expanded condition and the plate or collar 46 engaged with the workpiece.

In FIG. 7, the punch point 18 has pierced the workpiece W and a slug S of the workpiece W is removed therefrom. The springs 47 are in compressed condition with the enlarged head 44 of the guide pins 43 positioned adjacent the upper end of the bores 42 in collar 41. All of the load transmitted from plate 46 to the springs 47 is transmitted through the collar 41 to the snap ring 39 and shoulder 37 on the punch 34 to thus protect the ball lock 30, 3'1, 32. Accordingly, as the punch is pushed downwardly through the workpiece and as it bursts through the workpiece with the explosive effect aforedescribed, the entire shock load is absorbed by the springs 47; and as the punch is withdrawn from the workpiece, the stripper 40 acts between the snap ring 39 and shoulder 37 and the workpiece W to strip the workpiece W from the punch.

As seen in FIG. 9, the snap ring 39 has a radially extending channel or open portion 50 therein through which a suitable tool may be inserted to disengage ball 30 from depression 32 to release the punch from the punch retainer 12.

Accordingly, with the present invention, holes have been punched through inch thick steel, and a /8 inch diameter hole has been punched through a 1 inch thick piece of mild steel without danger of damaging or shearing the means, such as set screws orother suitable means, which hold the punch to the punch retainer. With conventional devices, the means securing the punch to the punch retainer would likely be damaged or destroyed if a piece of material of this size were punched or pierced, particularly where punches are utilized which are removably mounted to the punch retainer. 7

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

What is claimed is:

l. A punch for punching holes in material, comprismg:

punch retaining means,

a punch having a head end and a piercing end,

punch securing means engaged with the head end of the punch securing the punch to the punch retaining means,

axially downwardly facing shoulder means on the punch adjacent the head end thereof axially spaced from the punch retaining means, and

resiliently yieldable stripper means disposed in substantially coaxial relation with the punch, said stripper means including a cap means secured to the punch in coaxial relation therewith in engagement with said shoulder means and axially spaced from the punch retaining means, saidv yieldable stripper means engaged at one end against said cap means and having its other end substantially coplanar with the piercing end of the punch, so that when said punch is forced through a piece of material to pierce the material the stripper means engages between the piece of material and the cap means and thus acts as a shock absorber absorbing forces resulting from piercing the piece of material and effecting stripping of the pierced piece of material from the punch, with stripping loads imposed on the stripper means transmitted to the shoulder means on said punch to thus protect the punch securing means supporting said punch in said punch retaining means.

2. A punch for punching holes in material, comprising:

a punch retainer,

a punch secured at one end thereof to the punch retainer and having axially downwardly facing shoulder means thereon spaced from the punch retainer,

punch securing means engaged with said one end of said punch securing said punch to the punch retainer,

resiliently yieldable stripper means disposed in substantially coaxially surrounding relation to the punch, and

a cap means secured on the punch in engagement with said shoulder means in axially spaced relation to the punch retainer, said stripper means engaged at one end thereof against said cap. means and extended at its other end into substantially coplanar relation with the other end of the punch, so that when a sheet of material is pierced with the punch and the punch bursts through the material, the resulting force imposed on the stripper means is transmitted to the shoulder means on the punch itself, thus protecting the punch securing means from said force.

3. A punch as in claim 2, wherein the stripper means comprises an elastomeric cylindrical stripper fitted over the punch and secured at its upper end to the punch adjacent the upper end of the punch.

4. A punch as in claim 3, wherein said elastomeric stripper is elongate and has a central bore therethrough of substantially the same diameter as the diameter of at least a portion of said punch, said cap means including a hard rigid annular cap secured to each end of said elastomeric stripper, one of said caps having a plurality of radially extending openings therethrough, and set screw means extended through said openings and into engagement with said punch to secure said stripper to said punch, the other of said caps engageable with a workpiece to be pierced by said punch.

'5. A punch as in claim 4, wherein said punch is an elongate, solid, cylindrically shaped member having a body portion of the same diameter as the internal bore through the stripper, a reduced diameter punch point, and a diameterically enlarged punch head received in and secured to said punch retainer means, and an annular, concave groove in said punch between said head and body portion defining with saidhead said axially downwardly facing shoulder against which said one cap of said elastomeric stripper engages, and said means for securing said punch to said punch retainer means comprises a plurality of inclined set screws extending through the punch retainer means and into engagement with the head portion of said punch.

6. A punch as in claim 4, wherein said punch is an elongate, solid, cylindrically shaped member having a body portion of the same diameter as the internal bore through the stripper, a reduced diameter punch point, and a diametrically enlarged punch head received in and secured to said punch retainer means, and wherein said means for securing the punch to the punch retainer means comprises a ball lock means including an inclined bore in-said punch retainer, a shallow, concave depression in the outer surface of said punch head, and a ball in said bore and shallow depression and urged into engagement with said punch by a coil spring engaged against said ball.

7. A punch as in claim 2, wherein said stripper means comprises coil spring means, said cap means including an annular collar secured to said punch adjacent an upper end portion thereof and an annular workpiece engaging plate adjacent the lower end of the punch, said coil spring means engaged between said annular collar and said annular workpiece engaging plate to urge the workpiece engaging plate downwardly relative to said punch.

8. A punch as in claim 7, wherein an annular groove is in said punch adjacent an upper end portion thereof and a plurality of set screws extend radially through said annular collar into engagement with said groove to maintain said collar and said coil spring means in position relative to said punch, an annular groove in said punch above said collar defining and axially downwardly facing shoulder, a snap ring received in said groove, and said annular collar engaged against an undersurface of said snap ring to transmit forces imposed on said coil spring means and collar to said snap ring and to said shoulder and punch.

9. A punch as in claim 8, wherein a plurality of circumferentially spaced axial bores extend through said collar, a guide pin slidably received in each of said bores in said annular collar at one end thereof and threadably engaged with said annular workpiece engaging plate at the other end thereof, and a coil spring disposed about each said guide pin and engaged at its opposite ends with the annular collar and workpiece engaging plates, respectively, said punch having a head portion above said snap ring, said head portion having substantially the same diameter as said punch and secured in said punch retaining means by a ball lock Disclaimer 3,87l,254.-Lawrence V. Whistler, Jr., and Lawrence V. Whistler, III, Kenmore; and Harold J. Whistler, Williamsville, NY. MEANS FOR PIERCING AND STRIPPING THICK MATERIAL. Patent dated Mar. 18, 1975. Disclaimer filed Jan. 19, 1981, by the inventors.

Hereby enters this disclaimer to all nine claims of said patent.

[Oflicial Gazette April 7, 1981.]

Claims

1. A punch for punching holes in material, comprising: punch retaining means, a punch having a head end and a piercing end, punch securing means engaged with the head end of the punch securing the punch to the punch retaining means, axially downwardly facing shoulder means on the punch adjacent the head end thereof axially spaced from the punch retaining means, and resiliently yieldable stripper means disposed in substantially coaxial relation with the punch, said stripper means including a cap means secured to the punch in coaxial relation therewith in engagement with said shoulder means and axially spaced from the punch retaining means, said yieldable stripper means engaged at one end against said cap means and having its other end substantially coplanar with the piercing end of the punch, so that when said punch is forced through a piece of material to pierce the material the stripper means engages between the piece of material and the cap means and thus acts as a shock absorber absorbing forces resulting from piercing the piece of material and effecting stripping of the pierced piece of material from the punch, with stripping loads imposed on the stripper means transmitted to the shoulder means on said punch to thus protect the punch securing means supporting said punch in said punch retaining means.

2. A punch for punching holes in material, comprising: a punch retainer, a punch secured at one end thereof to the punch retainer and having axially downwardly facing shoulder means thereon spaced from the punch retainer, punch securing means engaged with said one end of said punch securing said punch to the punch retainer, resiliently yieldable stripper means disposed in substantially coaxially surrounding relation to the punch, and a cap means secured on the punch in engagement with said shoulder means in axially spaced relation to the punch retainer, said stripper means engaged at one end thereof against said cap means and extended at its other end into substantially coplanar relation with the other end of the punch, so that when a sheet of material is pierced with the punch and the punch bursts through the material, the resulting force imposed on the stripper means is transmitted to the shoulder means on the punch itself, thus protecting the punch securing means from said force.

5. A punch as in claim 4, wherein said punch is an elongate, solid, cylindrically shaped member having a body portion of the same diameter as the internal bore through the stripper, a reduced diameter punch point, and a diameterically enlarged punch head received in and secured to said punch retainer means, and an annular, concave groove in said punch between said head and body portion defining with said head said axially downwardly facing shoulder against which said one cap of said elastomeric stripper engages, and said means for securing said punch to said punch retainer means comprises a plurality of inclined set screws extending through the punch retainer means and into engagement with the head portion of said punch.

6. A punch as in claim 4, wherein said punch is an elongate, solid, cylindrically shaped member having a body portion of the same diameter as the internal bore through the stripper, a reduced diameter punch point, and a diametrically enlarged punch head received in and secured to said punch retainer means, and wherein said means for securing the punch to the punch retainer means comprises a ball lock means including an inclined bore in said punch retainer, a shallow, concave depression in the outer surface of said punch head, and a ball in said bore and shallow depression and urged into engagement with said punch by a coil spring engaged against said ball.

9. A punch as in claim 8, wherein a plurality of circumferentially spaced axial bores extend through said collar, a guide pin slidably received in each of said bores in said annular collar at one end thereof aNd threadably engaged with said annular workpiece engaging plate at the other end thereof, and a coil spring disposed about each said guide pin and engaged at its opposite ends with the annular collar and workpiece engaging plates, respectively, said punch having a head portion above said snap ring, said head portion having substantially the same diameter as said punch and secured in said punch retaining means by a ball lock mechanism.