US2576328A - Punch press - Google Patents

Description

Y Nov. 27, 1951 w. L. ALLlsoN 2,576,328

PUNCH PRESS Filed Sept. 10, 17949 FOOT OPERATED VALVE 53 akM/j/ (62A (52 56 sa s (54 64;. 42) 47 6 [44 {41(.39 37) Y- l. Q .n l J 53 :5i 62 50 521 :L /6.4. 60 y i 2, l F 1 l/ .l 23 /5/ Q1 l||| u .'l'szt- (a *alf v 58/ la L42 AT TORNEY Patented Nov. 27, 1951 UNITEDg 4STATes rATsNT oFFlcs,

William L. Allisonlhoenix, Ariz., assignor to v Allison SteeVManufacturing Company, Phoeniin'Ariz.',"a company of Arizona Application September 10, 1949, Serial No. 114,999

3 Claims.. (Cl. 164-104) 'This invention relates to improvements a punch press and more particularly` provides improvements in a, punch press with a continuously oscillating head.

In a punch press ofthe oscillating type, the head suspended above a stationary table continually moves up and down transverse ,to the table. A punch holderis slidably disposed in the oscillating head with a punch coupled to its lower end. The punch in this oating position lightly impinges the surface of a work piece on the table but does not pierce it. When the punch in the floating position strikes the work, the punch and holder will move upwardly with respect to the head. If the punch is to pierce the work, the holder must be locked to the head. In the prior art, this is accomplished by moving manually a locking piece or plunger into -a free space above the punch holder. The punch on the next downward stroke pierces the work on, the

table.

An operator using the manual locking mechanism must ltime insertion of the plunger'or locking piece with the stroke of the press. Manual operation is slow, and frequently the plunger will be engaged only partially. l That is, the lower face of the plunger will cover only part of the upper vend of the holder before the punchstrikes the work. In consequence, thereis excessive wear on holder and plunger and not infrequently, a

broken part. i

To remedy the shortcomings of the manually operated plunger, the plunger of my apparatus is actuated pneumatically. For that matter, the plunger may be actuated by any compressed fluid, liquid or gas. Hereinafter, the ,term pneumatic is used to describe all such fluid-actuated means. This pneumatically actuated plunger is much faster and hence, more certain to cover completely the top surface of the punch holder. For this reason, wear and breakage are greatly reduced. In the preferred form of my device, the operator need not remove a hand from the work piece to actuate the plunger, because a foot pedal is utilized to control an air valve that actuates the plunger. This results in a safer punch press.

Furthermore, with the use of my pneumatically actuated plunger, the number of stroke cycles per minute may be increased because the engagement of the plunger is dependent no longer upon manual operation which is necessarily slow. Hence, my invention results not only in an improved means of engagement but also in more rapid operation.

In a presently preferred form of my apparatus,

amember oscillates transversely to a table upon which the work is laid. .A punch or punch holder is disposed in the member and arranged to slide transversely to the table. If the punch holder is utilized, the punch is attached to the holders end. Means pneumatically actuated lock the punch or punch holder to the oscillating member when the punch is to pierce the work. Means are provided for releasing the punch or punch holder from the locked position after the punching operation has been completed. y

These and other aspects of my invention will be understood more thoroughly in light of the following detailed description, taken in conjuncftion with the accompanying drawings in which; Fig. 1- is a fragmentary front elevation of a presently preferred form of my apparatus; v

Fig. 2 is a side elevation of the apparatus of Fig. 1 as viewed from the section line 2-2 of Fig. 1;

Fig. 3 is a front elevation, partly insection, taken along line 3-3 .of Fig. 2 and showing the punch piercing the work; and 'Y Fig. 4 is a top plan View along line 4-4 of Fig. 3.

As illustrated in Figs. 1 and 2, a body I 2 is attached to the under surface of a cross head I3 by bolts I5, I Ii, the heads of which are slid into a pair of T-shaped grooves I'I in the cross head. An air cylinder housing I8 is fastened to the body parallel to the under surface of the cross head by four set screws I9. A punch holder 2l is carried in a slidable, upright position in Vthe body. A coaxial punch 22 is fastened to the lower end of the holder by a coupling nut 23. .I

A table 25 below the cross head supports the work. A plate 21 is fastened to the table by a pair of bolts 28, 29, the heads lof which are slid into T-shaped grooves 30 in the table. An annular bushing 33 with its bore 34 in alignment with the punch is mounted in a cylindrical recess 35 of the plate. The bore of the bushing receives the punch after it has pierced the work.

In Fig. 3, an air port 3l in the end of the air cylinder housing is connected by a hose 38 (see Fig. 1) to a source `of compressed air through a foot operated valve 63. The air port opens into a horizontal bore 39. A piston 4I slidably disposed in the bore is press fitted over one end of a plunger shaft 42. The piston abuts against a Vertical shoulder of a swollen section 44 of the shaft. A helical spring 46 coaxial with the shaft is placed between the other shoulder of the swollen section and a vertical face 41 of the body member.

The plunger is substantially a rectangular block with its lower face partially cut awayjto Y permit movement of the plunger over a rectangular head 55 of the punch holderewhich projects upwardly into the cavity. A slot 58 inthe 'central portion of the plunger (see Fig. 4) permits the plunger to move along its path, even -thouglri the bolt IG which fastens the body to the cross head extends vertically l.through the cavity and plunger.

JThe punch holder is cylindrical and is 1slidably held ina Vertical bore 60 of V'the body by its rectangular head 55, which normally rests on the floor of the cavity. The -corner 62 or the head adjoining 4the lower face of the plunger is rounded to provide smoother operation. Similarly the 'corner 62A of the plunger 52, which contacts the cornercf the head, is rounded.

Whenever the punch press is in operation, the cross head andthe members attached thereto will oscillate up and dow-n above the work on the table. As long as the space above the head of the punch holder is clear (i. e. when -the plunger is in its far right position as shown by dotted lines 63, `64 in Fig. 3), the punch Will strike the work lightly. When the `guide mark on the work is in alignment with the point of the punch, the foot-operated valve is actuated by the operator and vair 'under pressure is forced into the bore through the air port, moving the piston, shaft, .y

and `plunger to the far left A(as illustrated in Fig. 3). Then the plunger occupies the former free space above the punch holder, and the punch on the next downward stroke will penetrate the work.

When the operator removes his foot from the foot valve, the air escapes and the helical spring returns the piston, shaft, and plunger to the unengaged position as indicated by the dotted lines in Fig. 3.

It is to lbe understood that the form 'of my invention, herein described and illustrated, is a preferred embodiment and that various changes may be resorted to without departing from the Yspirit of my invention, or scope of the claims. For example, the helical spring could be'eliminated and the plunger pneumatically actuated in both directions.

I claim:

1. In a punch press of the continuously oscillating type and including a table, a cross head oscillatable perpendicularly to the table, the combination comprising a body member affixed to the lower end of the cross head and having an 'elongated cavity extending transversely of the axis of oscillation and opening against the bottom 'face of the cross head, a bore in the bottom of said body member opening into said cavity adjacent an end thereof, a punch slidably mounted through said bore and having on its inner end an enlarged head of .larger diameter than said bore, a 'gag slidably mounted in said cavity, the gag being shorter than said cavity but of substantially the same cross section and having a notch in the lbottom thereof extending from its inner end to form an overhanging projection insertable `between the bottom of said .cross head and .the top surface .of said .enlarged head to ll .the space therebetween, hydraulic means for displacing said gag in the direction of said enlarged head, spring .means for retracting the gag, and a foot operatedY valve forcontrolling .the loperation .of ysaid hydraulic means. Y

2. Apparatus according tto claim 1 wherein Athe :gag has Ia longitudinally elongated slot centrally -spaced between its sides and extending through thegag from top Lto bottom and the body member is affixed to the cross head .by a bolt .passing through the `said slot in vthe gag, the vgag being vfree .to .oscillate longitudinally through a displacement defined by the longitudinal .elongation of said slot.

3. Apparatus according to claim 1 wherein said enlarged head .of .the punch is rounded along the .edge directed .toward said gag and the outer 1ow- .er edge of the overhanging projection .of 4said gag is rounded, the arrangement being such `that the edge of the head Vand the roundededge of the -gag 4engage as the gag is .displaced towards the head. Y

WILLIAM L. ALLISON.

REFERENCES CITED The following references are of record in the file of this patent: v

UNITED STATES PATENTS Number Name .Date

627,153 Tennant June 2.0, 1899 1,557,385 Tastenhoye Oct. 13., 1925 1,856,175 Towle May :3, 19.32

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