US2212678A - Perforating punch and die assembly - Google Patents

Description

Aug. 27, 1940.

l.. v, w'Hls'rLER lLa-r AL 2,212,678 PEW'ORAING*PUNGH` AND DIE ASSEMBLY Filed April 14, 1939 5 Sheets-Sheet 1 Aug. 27, 1940. L. v..w|||s'rLER Er A. 2,212,678 PEnFon/Trnewruuc AND DIE ASSEMBLY .i

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Patented ug. 27, 1940 'f UNITED STATES PATENT OFFICE PERFORATING PUNCH AND DIE ASSEMBLY Lawrence V. Whistler and Sanford A. Whistler, Kenmol-e, N. Y.

Application April 14, 1939, Serial No. 267,810

8 Claims. (Cl. 164-118) approximate seven to eightA per vcent of metal thickness, and a variation in the axes of the punch and die of one half of such clearance would result in the punch contacting with the Wall of the die, vthereby causing friction which would wear out thepunch and die cutting-edges and also cause undesirable burs to be formed on the stock being perforated. I

y Having in mind to overcome such objectionable features, it is one of the objects of our invention to provide a die and punch device in which the axis of the punch is assured coincidence with the axis of the die, with the result that the punch will enter the die with exactly the same clearance between the cutting-edge of the punch and the cutting-edge of the die at all points in the circumference of the punch.

Anotherlobject of our invention is to simplify the making of perforating dies from a cost standpoint with the assurance otherwise impossible to obtain of establishing axial or concentric alinement between the two, and also to avoid wearing out of the punch and-die cutting-edges under friction, now so common in the operation of punch and die devices.

Another object of our invention is to provide securing Shanks for the punch and die, whereby it is possible to provide perfectly coinciding shank-receiving openingsvin the punch and die holder plates of a punch and die-device capable of being formed thereinlwhile such'plates are maintained in the registering relation in which they would be used in the act of punching metallic sheets or other stock material.-

It is also an object of our invention to have the securing Shanks of the punch and die of the'v same diameter so that the shank-receiving openings in 'the punchA and die holder plates canA be formed with a single drilling andboring or forming operation.

' It is also an object of our invention to provide a vdie-device comprising two metallic parts of different densities or hardness, one of which y serves as the body portion or foundation of the die device and the other as the die proper, or die-v bushing as it may be termed, the foundation or body portion, or the die holder as it may be termed, being utilizable with die-bushings having Rsssufn JAN l 8 1943 punch-receiving holes of different diameters so that die-bushings can be applied to standard foundations or body portions in conformity with l the punches to be used in connection therewith.

It is thus of advantage to use as the foundation 5 or body portion a malleable or other casting or a machined part and suitably connect therewith a steel or other hardened die-bushing of desired size, the punch hole in the die-bushing having in all instances a diameter which does not exceed 1o that of the plug passage formed through the foundation or body portionv and invariably having its punch hole of smaller diameter than said plug passage. 1

A further object of our invention is to cast the foundation or body portion of malleable or other comparatively soft iron or machine the same from bar stock while the die-bushing or die proper is formed of tool-steel or other hardened metal and brazed, hydrogen-welded, or any other means 2 employed for securing the die-bushing to the foundation or body portion to make the diebushing substantially anintegral part thereof.

With `the above and other objects in view to appear hereinafter, Vour invention consists in the novel features of construction and in the arrangement and combination of parts to be hereinafter described and more particularly pointed out in the subjoined claims.

The invention also consists in the novel method 3 of preparing the set-up for' the punch and die set, including punch and die holder plates adapted to respectively receive the securing shanks of the punch and die andthus assure coaxial alinement between the` two.

Referring'to the figures' of the drawings',

Fig. 1 is a front elevation of a punch and die set shown in association with a portion of a press of the conventional type, the press having a die shoe and a punch holder adapted to be mounted' on or secured to the table and the ram of the press, respectively.

v/being broken away.

Fig. 5 is an enlarged vertical section taken on line 5--5, Fig. 1. l'

` Fig. 6 is an enlarged vertical section taken on line 66, Fig. 1.

Fig. 7 is a diagrammatic View, including a section of apunch, a portion of a piece of sheetmetal to be punched thereby, and showing in dotted lines the die underneath the sheet-metal and its true relation to said punch as provided for under our improved method of setting up the punch and die device.

Fig. 8 is a sectional view of the piece of metalY shown in Fig. 7 after punching the same under the relationship provided between the punch and shown in Fig.' 9 after punching the same underV the relationship existing between the punch and die illustrated in said gure and showing a burr formed on the sheet-metal around one-half of the wall of the punch hole therein.

Fig. 11 is a horizontal section taken on line II-I I, Fig. 6.

Fig. 12 is a view of the punch and die plates assembled and retained in proper relation by dowel pins, such as employed for properly positioning the said plates within the press and showing the method of vforming the shank-receiving openings in said plates whereby the .shanks of the punch and 'die are assured true Acoinciding relationship to the end that the length of the life 'of the punch andV die will be greatly augmented and all burrs usually formed on metal punched will be eliminated.

Now/.referring to the drawings in detail, the reference numeral4 I5 designates the die-shoe of a press which may be secured to the bed or table of the latter, and which has rising therefrom plate 22 is mounted on the die shoe I5 and this is also fastened in place by means of screws, bolts, or other fastening devices indicated by dotted li'nes 23 in Fig. 2.

We have shown the punch holder-plate and the die holder-plate of exactly like dimensions so that these may be placed one over the other with their edges in perfect registration. Dowel pin openings 24 may be formed in these plates while one surmounts the other, or these openings' may be formed under other conditions; vand registering'f'peningS are formed in the punch holder and die shoe so that dowel pins 25 may be driven through the punch and die holder-plates and enter the punch holder and the die shoe, respectively. It is'of course, necessary to have the dowel pinv openings -24 in the punch and die holder-plates register with openings in the punch -holder and die shoe so that these plates may be positioned properly before securing them in place. We prefer to form the dowel pin openings 24 in the punch and die holder-plates when they are mounted one on the other, as shown in Fig. 12, so that two of the dowel pins 25 may be driven into said openings 24 for positioning the plates in v registering relation.

2B designates the punch devices, considered as a' wno1e. and 21 the die devices. nach die-device 21 comprises a die-holder or body portion 28 cast of malleable or other durable and inexpensive material, it being preferably cylindrical in cross 'ing 3I intersecting said cylindrical opening and having an inclined rider wall 32 merging into the cylindrical wall of the slug-receiving opening30.

v33 designates the die-bushing or die proper which is formed of steel or other hard material, and it is externally chamfered at its lower edge, as at 34 (see Fig. 5). This die-bushing has a punch hole 35 formed axially therein which, if cylindrical, does not exceed in diameter that of the cylindrical slug-receiving opening in the die-holder 28 and invariably is smaller in diameter so that a portion of the die-bushing overhangs the said cylindrical slug-receiving openings 30, as aat 36. v

When mounting the die-bushing 33 on the dieholder or body portion 28 of the die-device with the axes of both coincident, a V-shaped external groove is formed at the parting line, designated 31, Fig. 5, into which welding flux 38 may be placed while in the act of welding the anterior regions of the die-holder and die-bushing together. vIn thismanner the die-bushing and dieholder or body portion of the die-device are made practically integral; but any other manner 4ofv ri'gidlyA connecting the die-bushing to the dieholder or body portion may be employed, even though all of the advantages of hydrogenwelding are not thus retained.

It will be apparent from the foregoing that the die-holder may, within certain limits, serve as a foundation or base for die-bushings having purnch openings of Various Asizes or outlines so that diebushngs, regardless of the type of punch-holes therein, may be secured to body portions which d o not vary from each other in any respect or any dimensions at any point, even though the ,die-bushings are of like o r diiferent sizes internally and to an extent externally. The dieholder or body portion 28 is reduced in diameter at. its lower end to form a securing shank 39, and this snugly tsinto a bore 40 formed in Ythe die holder-plate 22. The bore 4l is counterbored at its lower end or. at the bottom of the die holder-plate, as at 4I, thereby forming a downwardly-facing shoulder 42. The smaller Aportion of the bore 40 is slightly longer than the shank 39 of the vdie device, and said shank is provided with' an axial 'screw-threaded bore 43 into which is threaded a cap screw 44. Between the head of said cap screw and the shoulder, a washeris placed which, when the screw is tightened, is forced rmly against s aid shoulder, thus causing the shank 39 to be tightly threaded within the bore 40 and theA bottom of' the die-holder or bodyportion 28 to be drawn tightly against the upper' surface of the 'die holder-plate. It is to be notedthat the'shank 33 is coaxial with the punch opening 35 in the diebushing 33.

Cooperating with the die-device is the punch device 26 which comprises a punch 46 and stripper means 4'I V wherebyA the sheet-metal to` be punched, designated by the numeral 48, is stripped from the punch after being perforated by the latter. This punch is in the form of `anvelongated cylindrical member reduced in diameter at its upper end to form a securing shank ,49 and also along its lower portion, if desired,

. to conform in diameter to the punch opening 35 in the die-bushing 33 cooperating therewith; suicient clearance of course being provided by innitesimal variation in the diameters of said punch opening and punch.' `\\By reducing the upper end of this punch an upwardly-facing shoulder 50 is formed thereon. The punch holderplate 20 is provided with a bore 5I counterbored at its upper end, as at 52, to form an upwardly-facing shoulder 53, the length of the smaller portion of the bore 5| being somewhat greater than the shank 49. The shank is provided with a threaded bore 54 adapted to receive a cap screw 55 between the head of which and said shoulder 53 a washer 56 is arranged. Upon tighteningsaid cap`screw, the punch will be drawn firmly up into the bore of the punchholding plate until the shoulder 56 of the punch bears tightly against the under side of said plate.

The stripper Ameans 41 comprises a head 51 having a sleeve 58, from the lower end of which arms 59 project radially in opposite directions, said sleeve being positioned on the punch and fastened thereto in any suitable manner. We, however, have shown the punch provided with a circumferential groove 60 into which is fitted a pin 6I driven through said sleeve, the fastening means comprising` said groove and pin enabling the pin to be passed through the sleeve Y and-entered in the groove regardless of the rotary position of ysaid punch or the stripper means. l

Associated with said stripper head 51 is a stripper bar 62 which is spaced from and arranged parallel with said head and it is provided centrally between its ends with an opening 63 in which the lower or punch end of the punch is normally retained. Slidably arranged in the arms 59 of the stripper head are combined retainer and guide-pins 64 having heads 65 at their upper ends. Said pins are reduced in diameter at their lower ends and threaded, as at 66, into threaded openings 61 formed in the stripper bar. 'Ihe shoulders 68 formedby reducing the lower ends of the said `combined retainer and guidepins bear against the upper side of the stripper bar. Surrounding each of these pins are spiral springs 69 which exert their force against the under side of the stripper head 51 andthe upper side of the stripper bar 62, the heads 65 of said pins serving as stops to limit the downward movement of the stripper bar.

It will be apparent that by reason of the shank vof the punch 49 and the shank of the die being of equalfdiameter, the bores receiving them can be vformed in one operation by mounting the punch holder-plate on the die holder-plate, or reversely; this being accomplished by forming the counterbored portions of said bores from the opposite exposed faces of said/plates and then continuing the normal size/nf the bores in which the shanks of the punch anddie' are `to be iitted,

.eter for preventing 4movement laterally or end- A wise of said plates while superimposed. In the drawings we have shown the punch holder-plate and the die holder-plate of exactly the same dimensions, but where the dimensions diler in one plate from that of the other they may be mounted one on the other and so retained in any approved manner, so long as the shank openings 24 in the plates are drilled or otherwise formed through both plates while so maintained. The shank-receiving bores for the punch and die devices are therefore of the same diameter in both plates. and since the shanks of both thegpunch and die devices are of like diameter and fit snugly into the shank-receiving bores, assurance is had that when placing said plates within the press or otherl machine employed for punching sheet-metal or' other similar stock, true and perfect alinement of the punches and dies will be had, it of course being understood that the punch holes in the die-bushings have-'their axes in true alinement with the axes of the shanks of the die-devices of which said die-bushings form part.V It may also be stated that by reason of the lateral opening formed in each of the die-devices the slugs or other elements punched from the sheet-metal or other stock lbeing operated upon, are delivered onto the die holder-plate and can be easily removed as they accumulate.

With this invention assurance is had that each punch will be concentric to the punch hole in the die-device with which the punch cooperates, as clearly shown in Fig. 7, and for a clean-cut and perfect punch operation-say for example in i punching 5%000 steel-clearance between the punches and dies should approximate 1%000 of an inch. Holes punched through suck stock 'will have clean-cut walls without any burrs or other rough edges being formed, and this is clearly illustrated in Fig. 8.

In Fig. 9 we have illustrated a conditio commonly existing in punch presses by reason pf the fact thatthe punch has its axis slightly out of alinement with the axis of the die cooperating therewith. A'I'his results in the punch entering the die oi center, oftentimes with the punch coming in contact with the wall 'of the punch hole in the die at one side of its center, while the clearance at the other side of the center is increased to 9/1000 of an inch,thereby causing rubbing action or friction betweenvthe punch and die wall. The punch and die cutting edges become worn away under such conditions, causing a rough wall to be formed in the punched hole at one side of its center. When punches and dies kso mutilated are used, the sheet-metal is pressed downwardly at the other side of the center where the tincreased clearance space is provided and causesI a burr to be formed, as clearly shown at 10, Fig. 1.9. This results in imperfect work, calls for frequent replacement of punches and dies, and necessitates further operations on the,

punched sheet-metal or other stock in order to dispose of the burrs projecting from the punched holes therein. l R

For accurate Work such punched material is not acceptable, even though the burrs be iinally reduced or eliminated by hammering or other operations, since such operations would not assure perfect outlines for the punch holes in the Y metal.

It Will'be clear that any attempt to straighten out burrs on the wall of a round,

punched opening in sheet-metal by avhammering operation .would y result in anl opening being formed that would be more or less oval, and in any' event vwould not be truly circular, and this distortion of the punch hole would occur regardless of the cross sectional formation of the punch and the punch hole in the die-bushing, since the same diiculty would be encountered with any other form of punched hole formed under like circumstances.

We regard the formation of securing Shanks of like diameters on the punch and die of marked importance in a punch and die assembly or mechanism for the reason that the holder-plates, carrying members, or parts of the punch and die assembly receiving said securing shanks can be drilled or otherwise manipulated to form the receiving openings for said shanks with one operation of a drill or other suitable tool, and thus assurance be had of so positioning the punch and die that the axes of both are coincident and that the clearance between the punch and the punch hole in the die-device Will be the same at every point of the circumference of the cutting edges of both thepunch and the die-device.

We further regard the employment 4of a dieholder or body portion for the die-device constructed of any suitable metal for use in connection with die-bushings of various sized punch holes as of considerable importance, since it enables various sizes of punches to be used in connection with mating die-bushings on a die-holder or body portion having a definite size and shape. This is particularly true in view of the provision made for' securely fastening the die-bushing to the die-holder or body portion of the die-device, especially when the die-bushing is brazed, welded, or otherwise permanently connected together; thereby providing means to make the die-bushing a rigid part of or substantially integral with the die-holder or body portion of the die-device.

We also wish to stress the fact that by reason of merging the wall of the lateral opening in the body portion or die-holder with the peripheral, wall of the cylindrical axial opening in the u p` per end thereof, the inclined rider face so formed will prevent clogging of the slugs cut from the sheet-metal or other stock within the body portion or die-holder. 'I'his rider face, as is yclearly shown in Fig. 5, is formed in an arc of a circle at least along a portion of its length, so that when the slugs drop thereon, diametrically op- .posite points of the slugs contact the concaved Wall and thus minimize the friction between said wall and the slugs. Free sliding motion for the slugs vthrough the lateral discharge provided therefor is assured. Moreover, the particular arrangement of the punch and die device shown and described enables punch openings to be formed in sheet-metal or other sheet material with much closer centers than heretofore posv sible. i

The lateral discharge opening provided in the body portion or die holder of each die-device, whereby the punched out slugs are delivered laterally onto the die holder-plate, eliminates the slug passages usually formed through said plate ings will at any time be necessary in the die shoe and the bed or table of the press.

By providing the punches and die devices with sible.

Having thus described our invention, what (we claim is:

1. In a ,punch and die assembly, a punch holder-plate having an opening therein, a die holder-plate spaced from said punch holderplate and having an opening therein in axial alinement with and of a diameter corresponding to the opening in said punch holder-plate, a

punch having a shank fitted into the opening inl said punch holder-plate with its axis coincident with that of said opening, a die-device having a shank fitted into the opening of said die holderplate and of a diameter corresponding to the diameter of the shank of said punch, said diedevice having a slug-discharge opening to deliver slugs therefrom punched from sheet-stock, and means axially engaging and securing the shanks of said punch and said die-device in said openings. '-i.|,, 2. In a punch and die assembly, spaced apa punch and die holder-members provided-with vertical axially-alined openings of like diameter permitting both openings to be formed simultaneously when placing one of said members against the other, means for securing said holder members in operative separated positions and in which said openings are retained vertically axially alined, punch and die devices having securing Ashanks of like diameters and corresponding in diameter to that of the openings in said punchand die holder-members, said-securing means for said holder-members being independent of said punch and die devices, said shanks having axial screw-threaded bores, a securing screw threaded into the shank of said punch device from the upperside of said punch holder-member, and a securing screw threaded into the shank of said die device from the under side of said die holdermember, said die-device having a slug-discharge opening to deliver slugs therefrom punched from sheet-stock.

3. In a punch and die assembly, a punch holder-plate adapted to bear with its upper side against a punch shoe and having an opening bored therethrough counterbored at its upper end to form an upwardly-facing shoulder in said bore, a punch having its upper end reduced in diameter to form a securing shank and to provide an upwardly-facingv shoulder at the base of said securing shank, said shank being fitted in said opening and having an axial threaded bore formed therein opening at the upper end of said shank, a washer in the counterbored portion of said opening bearing against the upwardly-facing shoulder therein, and a cap screw passed through said washer and-threaded into the bore of said shank, said cap screw having its head bearing against said washer and being wholly within the counterbored portion of said opening.

4. In a pu'nch and die assembly, a die holderplate adapted to bear with its under side against (a die-shoe and having an openingbored therethrough counterbored at its lower end to form a downwardly-facing shoulder, a die-device having its lower end reduced in diameter to form a securing shank and to provide a downwardlyfacing shoulder at the -upper end of said securing shank, said. shank being tted in said opening and having an axial threaded bore formed therein opening at the lower end of said shank, a washer in the counterbored portion of said opening bearing against the downwardly-facing shoulder therein,I and a cap screw passed through said washer'and threaded into the bore of said shank, said cap screw having its head bearing against .said washer and being wholly within the counterbored portion of said opening, said die-device having a slug-discharge opening to deliver slugs therefrom punched from sheet-stock.

5. A die-device comprising a body portion of cast metal having a slug opening extending downwardly from its upper end and continued laterally to one side of said body portion, a diebushing of hardened metal mounted on said body portion and peripherally welded thereto to form a substantially integral device constructed tegral device constructed from different metals.

7. In a punch and die assembly, co-operating punch and die holder members normally spaced apart and having co-axial openings therein of a given diameter and adapted to interchangeably receive correspondingly formed and sized parts of punch and die devices of varying sizes, combined with a punch device having a punch of selected size provided with a shank `secured in and of a size to iit the opening in said punch holder member, a die device having a die provided with a punch hole serving as a mate to said Punch and provided with a shank secured in and of a size to t the opening in said die holder member, means axially securing the shank vof said punch from the upper side of said punch holder member, and means axially securing the shank of said die device from thev under side of said die holder member, said axial securing means being wholly within rsaid punch and die holder members to enable said members to bear fully against parts to which they may be fastened.

8. A die device comprising a body portion having a. slug passage therethrough from its upper surface and provided with a peripherally chamfered upper end, a die bushing of hardened metal mounted on said body portion and provided with a peripherally chamfered lower end co-operating with the chamfered portion of said body portion to form a. peripheral V-shaped groove in the plane of the contacting surfaces of said body portion and die bushing, and welding flux applied in said V-shaped groove to secure said die bushing to said body portion.

LAWRENCE V. WHISTLER. SANFORD WHIS'ILER.

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