US2380485A - Apparatus for perforating sheet material - Google Patents

Description

July 31, 1945. G. F. WALES 2,380,485

` APPARATUS FOR PERFORATING SIHEET MATERIAL Filed March 18, 194:5 3 Sheets-sheet 1 l WM 7o h j (ATTORNEYS G F WALES APPARATUS -FOR PERFORATING SHEET MATERIAL Filed'March 18, 1945 y 3 Sheets-Sheet 2 O ,28 I i 3 Sheets-Sheet 3- INVENTOR my? ATToR YS Filed March 18, 1945 Patented July 3l, 1945 I George Wales, Kenmore, N. Application Mitch 18, 1943, Serial N0. 479,815

(ci. isi-s4) 34 Claims.

This invention relates to an apparatus for plmching holes at specified locations throughout the areas of sheets of material such as sheet the numerous rivet holes required in the thin metal panels or sheets which are used in aircraft construction to liorm the outer surfaces of wings, i'uselages, and the like. but the invention may be applied to other uses where relatively large numbers of holes are required in panels or sheets of.

materials.

The main object of my invention is to provide an apparatus and method for punching holes in metal, and is particularly adapted for punching sheet materials which is simple in construction,

economical to manufacture and use. and easily set up for use in a press.

Another object is to provide a multiple hole punching apparatus and a methodvof making same in which the punch carrier plate may be used as a drill iig for drilling the die plate when both plates are assembledto the other parts yof the apparatus in the same manner in which they are to be used in the punching operation. l

Another object is to provide such an apparatus for the successive accommodation of any number of pairs of punch and die carrier plates. thus requiring the preparation only of the plates when new patterns of holes are to be punched.

A further object is to provide an apparatus of this nature in which so-cal1ed non-critical materials may be used for the majority of parts especially the punch carrier plates, the base plates and the Ysupport members.

Another object of this invention is to provide A -ing a multiple hole punching die whereby they punching devices are interchangeable from one punch carrier plate to another and also with Another object is to provide a die plate foran apparatus of this nature which is made of a metal capable of being hardened, and hardened around the die openings.

A further object is to provide anapparatus of this description in which the punches may be instantly serviced bylifting them freely out of their guideways in the punch carrier plates to prevent lossof time when a punch fails.

These and other objects and the several novel h features of this invention are hereinafter more fully described and claimed and the preferred form of construction by which these objects are obtained. is shown in the accompanying drawings in which:

Fig. 1 is a front elevation showing a prefer-re design of my apparatus mounted on the stationary bed or bolster of a press and showing the reciprocating ram in its lowermost position in which the punches are driven through the work.

Fig. 2 is a plan view of the apparatus shown in Fig. 1. l

Fig. 3 is a fragmentary horizontal section taken on line 3 3, Fig. 2, showing the ram in a partially elevated position, and showing locating pins for correctly positioning the punch plate and die plate relatively to each other.

Fig. 4 is a fragmentary horizontal section similar to Fig. 3, but showing how the holes are drilled in the die plate preparatory to the ilnal assembly of the apparatus.

Fig. 5 shows an alternate method of drilling the punchand die plates together.

Fig. 6 shows how the punch plate holes are enlarged to accommodate the punch and punch guide elements.

Fig. 7 shows the die plate as it was drilled in '.Fig. 5 and being llame hardened before being drill bushings which are substituted for them when drilling a die plate by using each punch can-ier pme as a drm Jig for drimng the die apertures in coaxial alignment in its companion die plate. t

Another object is to provide an apparatus and method for punching. a multiplicity of holes in either in'tllcdl'llllnscri-immuun:open-ations. i tin.

placed in service.

F18. 8 is a fragmentaryv sectional view d the punching mechanism in an operating position, and showing a punch unit of modiiled construction.

Fig. 9 is a fragmentary section showing a modiiied construction in which one of the rails is connected with the base by a bolt passing through the rail and having its head arranged in a T- shaped or undercut slot, which latter extends crosswise of the base, and thus permits therail to be shiftedcrosswise to permit of using die plates and punch plates of different widths.

Fig. 10 is a plan view similar to Fig. 2, but Showing BtOD me means of mouiiled construcstandard punch press or similar machine which includes, among other elements, a lower supporting bed which forms the lower part of the stationary main frame of the press and on which is usually mounted a bolster plate and an upper ram which is guided upon the upper part of this main frame and movable vertically toward and from said bed.

In the space between the bolster and ram of the press. the perforating apparatus embodying my improvements is arranged and adapted to be operated by the movement of the ram toward the bed for the purpose of punching holes in the sheets of material which are fed to the perforating' mechanism.

The diierent features of my improved perforating mechanism may be variously constructed and still embody the underlying principle of the invention.

The preferred organization of my invention which is shown in the drawings is constructed as follows:

The numeral I represents .the stationary bed or bolster of a press and II the reciprocating ram ofthe press. The numeral I8, Figs. l to 4, represents a base plate resting loosely on the bed or bolster I0 of the press and I2 represents two supports having the form of bars or rails which are mounted in spaced relation on transversely opposite parts of the base plate and secured thereto by bolts 23 passing through flanges on the outer sides of these rails, as shown in Figs. l, 2, 3 and 4. On their inner sides the two supports or'rails are rabbeted to form upwardly facing shoulders,

shelves or ledges I4 on which the transversely opposite edges of a die plate I3 rest and to which these parts of the die plate are secured by means of cap screws I5. Between the rails I2 the die plate I3 may be supported by brace pins I5, which may be attached to the plate I3 by means of a threaded or otherwise prepared shank I1 at the upper end of this pin secured in an opening in the die plate, as shown in Figs. 1 and 3, said pin be used t0 support die plate I3, or any other being of the same length as the height of the means which provides support for the die plate while at the s ame time making provision for slugs punched ou't from the work-piece to be cleared from underneath the die plate. Each of the -brace bars I8 has its lower edge resting on the base plate I8 and-may be secured thereto by screws 46 or the like and has its upper edge cut away or recessed on a downwardly tapering angle rectly upon the bolster plate Il of a press, they are for the most part attached to a mounting or -base plate I8, to provide a unitary assemblage which may be fully prepared for operation outside of the press and merely slid onto the bolster plate I0 where it is ready for immediate operation. As the supports or rails I2 may be used for different widths and lengths of die plates, such as I3, and punchplates. such as 24, the base plate I3 may be small or large to suit the size of plates I3 and 24. It might be advisable also to employ in place of plate I8 a base plate IBI, Fig. 9 having T-slots running crosswise of this plate, as indicated by 25 in Fig. 9, in which case bolt heads 23| would extend into said slots 25 and nuts used fclirtcelamping the supports or rails I2 to said base pa Each of the supports or rails I2 is provided with an upper bearing surface 25 upon which is mounted one edge portion of a punch carrier plate 24, which carries vertically moving tubular punch guides 21, each of which is guided in holes 28 bored in this plate and held in an elevated position by light springs 28. 'I'he guide sleeves 21 are provided with vertical holes extending clear through for the-accommodation of punches each of which consists of Punch body 3| and punch head 32 at the upper end of the body.

In order to strip the work-piece 38 from the punch, resilient means are interposed between the underside of each punch head and the upper face of the respective guide sleeve, which means may take the form of helical springs, truncoconical washers, rubber, or any other means, such as rubber washers 33, and metal washers 34, alternating as shown in Fig. 8. Take-up washers 3|) are inserted between the lowermost rubber washer and the top of the respective guide tube or sleeve 3| when thel punch is new and these takeup Washers may be removed as the punch wears and is ground shorter and thus prevent over-compressing the rubber washers.

Preferably the punch unit 'is constructed so I that the height of the various punch units may be the same. This may be accomplished by having the upper end of the punch extend through its head 32 and providing a cap 300 with a central aperture into which the upper end of the punch may extend, as shown in Fig. 8. The cap also has a downwardly extending annular skirt portion 30| extending about the head. As the punch becomes shorter by grinding the lower end thereof, any washer 30 removed from its place above the upper end of the punch guide sleeve may be placed upon the head 32of the punch and below the cap 300, thus keeping the total distance from the plate 24 to the upper end of the cap the same.

first on one side of the bar, as shown at 20, and` then on the other side thereof, as indicated by 2|, thus staggering or alternating these recesses and providing a top surface 22 having an effective area suilcient to adequately `support the die plate I3, whileat the same time providing slug chutes or recesses which enables the bars to support the die plate when holes are punched close together, and provides means for the slugs from such holes to clear the lower ends of the die apertures.

While supports or-rails I2 may be mounted diregardless of the length of the punch.

'I'he punch plate 24 is attached to supports or rails I2 by means of bolts 35, and this plate is proyvided with openings 36 to provide access to bolts I5, which attach the die plate to the ledge of the supports I2 below the level of the punch plate.

The organization by which this apparatus provides Vthe simplicity of preparing the punch plate and die plate will be discussed later. Forthe present, let it be assumed that the plates have been prepared by forming the holes 28 in the punch plate (Fig. 6) for the punching elements in correct relation to each other as desired in the finished part. Also that the holes 42 for the bilis 35 have been drilled so that said punch plate may be bolted to the supports I2. Also let Ait be ar- `upon the base plate or in any other manner. fbeen formed and properly prepared to--slidably III for bolts Il have been formed in the die plate. Then the manner of assembling the apparatus is asfollows: r v

If brace pins I3 are used they are engaged with die plate I3 wherever required. If brace bars I3 are used, they are placed in position on base plate I3. The supports or rails I2 are then placed I3 in the approximate position to accommodate die plate I3 which is placed on. the ledges I4. By shifting the die plate and rail, one relative to the other, the screws I will iind tapped holes in the rails and may be tightened and this will clamp the die plate I3 in position where it will be resting on the brace bars Y I3, or pins I3. Punch plate 24 is then placed on the supports I2 and screws 35.

The holes in the die plate clamped by meansof the n, through which bolts Il extend, are enough larger than the body` of the bolt to provide easy assembly ofthe plate with the supports I2. The holes for bolts 35 in punch plate 24 are larger than the body of the bolt to allow the punch plate '24 to be shifted slightly to obtain proper concentric alignment of the die holes 31 with the punch guide holes 23 before being clamped tightly. `'ll'his alignment is obtained by inserting locating pins 45 in the punching device holes 23' of the punch plate as substitutes for preferably*` three punching devices. These pins are reduced at their lower ends to form pilots 46| which Just flt the respective die openings 31 in such manner that the two plates I3 and 24 may be positioned with all companion holes in concentric relation with one another. The two plates I3 and -24 are then both bolted tightly to the supports I2. Screws I5, being socket head cap-screws, are tightened by inserting a wrench through the openings 36.. The locating pins 45 are then removed and the punching devices reinstated, upon which the apparatus is ready to operate.

.It is taken for granted that gaging means must l be used to locate the work 3|! properly in the apparatus and pins 33, ora nest, may be used on the die plate for this purpose.

Another method of gazing the work properly is illustrated in Fig. 10, according to which holes 40| are formed in the work-piece, previous to the present operation and pilot pins 40 vare provided von the upper faces of the brace bars. These brace bars I9 are then adjusted so that pilot pins 40 on these bars engage the holes in-the workpiece when this piece is in correct relation to the punch and die units, in which case pins 33, or the nest, are not used. When pins 40 are used, the brace bars are anchored against movement by screws 46 in plate I3. Obviously the locating pins maybe arranged in the die plate I3, if desired. s

I have shown work-piece 33 projecting in front of the apparatus. 1f, however, the work enters entirely into the apparatus, it may be desirable punch plate and the bolts 33 and this plate is then clamped tightly in place on supports I2 which are bolted to the base plate I3.

A blank die plate Il of chrome-molybdenum steel, or other steel capable of being flame hardened, is then drilled to take the bolts Il, and this blank plate I3 is then slid onto ledges I4 and the bolts inserted through holes 33 in the tightened by means of a socket wrench engaging the socket head screws I5. Y

The next step which is novel in die construction consists of inserting a drill bushing 43 in one of the punch plate openings, inserting a drill 5| in the hole of this bushing, and drilling the die hole 31, as shown in Fig. 4. The size of the drill is such as to give the proper clearance between the punch and the die hole. All punching operations require that the die hole be larger4 than the punch by from 5% to 25% of the thicknessv of the material. The hole`44 in the drilll bushing will therefore be the size of the required die hole and not the punch size. As an example, if the punch is .125 in diameter and the metal to be punched .050 thick, the drill size will be 10% of .050 larger, or .130 in diameter. When drilling die plate I3 by this means, the support or brace bars I3 may be shifted around to provide positive support 4for the die plate. After one hole has been drilled, the drill bushing 43 is vremoved and placed in another hole 23 of the punch plate and the procedure repeated until all of the die holes are formed in the die plate. These die holes will then be in perfect alignment with the punch holes in punch carrier plate 24, and the portion of the plate about these holes can be hardened 'without removing the plates l from their supports by inserting a burner through the holes in the punch plate.

The die plate I3 may also be hardened` by a name 60' around the die holes (Fig. '1) by removimmediate; vicinity of the hole 31, to avoid warping of the plate I3, a ring 3i of flre clay or other material may be arranged about the vhole while the part Within the ring is heated. Of course, tliie plate may be removed for hardening if des red.

By extending the brace bars I9 forward as at 50 in Fig. 2 a feeding ledge is provided on which the work-piece may be placed before inserting it into the apparatus.

If desired, the punch plate and die plate may be held together by bolts IBI similar to the bolt I5 and while thus connected a die hole 31 may bebored therein and a companion preliminary hole 31| may be formed in .the punch plate in alignment with the hole 31 by a drill 5I. Thereafter the plates I3 and 24 are separated and each of the preliminary holes 31| is enlarged to receive to out out hand openings or notches like 4I to l enable the operator to place the piece in position properly. Sight holes 4|0 may be provided in the punch plate 24 through which the gage pins 33 may be easily seen. v y The preparation of the punch carrierplate 24 consists of first drilling and reaming the holes 23, wherever a hole is desired in the nnished piece. The holes may be located from templates After these holes have receive sleeves or tubes 21, the holes 42 are drilled in the punch plate larger than the diameter of distance from eachother and when a job is finished, the punch and die plates can -be removed from the supports which can thenbe used for 'another set of punch and die plates. Since thesa except the drilling and reaming ofI the holes, and they are, consequently, easily and economically made.

The method and apparatus described may be used in any case where a relatively large number of holes are required in a sheet of material, but are particularly desirable for many uses in airplane construction where it has been considered impractical to punch holes in plates because of the relatively high cost and time required to make the necessary hole punching dies. My improved apparatus can. however, be produced at a cost not more than the cost of drill Jig-plates now commonly used for stack drilling .the work, and

once the apparatus is made, the work can be don'e at a rate of from ten to fifty times faster than drilling. economy in the use of drills, which are replaced in my apparatus by the use of punches oi' simple and inexpensive construction.

With .the construction shown, a single set of plates may be provided with two or more series of holes for two or more different jobs, providing that the holes are so located ln the two sets of plates that they do not overlap or interfere'with each other. For example, there are two series of holes in the plates shown in Fig. 2, one series for use on the work-piece 38. The-punch units are shown positioned in these holes. The same plates maybe provided with additional holes 85 for use on another job. When theflrst :lob is being done, punch units are placed only into the holes of one series and whenthe second job is to be done by means of the same apparatus, all the punch and die units are removed from the first series of holes and are placed in the holes 85. This may require the use of other stopgages for positioning the work. In this manner, a number of different types of work can be-pro duced by means of a single apparatus.

I claim as my invention:

My apparatus also eilects a further l. A sheet material perforating apparatus comprising a base, spaced supports resting onsaid base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate and provided with guide openings in line with said die openings, guiding and stripping Itubes arranged vin said guide openings, punches slidable in said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes 'relative to said punch plate, and resilient means for raising said punches relative to said tubes.

2. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate and provided with guide openings in line with said die openings, guiding and stripping tubes arranged in said guide openings, punches slidable inv said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes relative to said punch plate, resilient means two plates are flat, they require no machining.

die openings, a punch plate mounted on said supports .in spaced relation to said die plate, punches slidable on said punch plate and adapted to cooperate with said die openings, vresilient means for'stripping said punches from the work, and bracing means interposed between said die plate and said base including a bar engaging its upper edge with the underside of said die plate and its lower` edgewith the upper side of said base and provided on its upper edge with recesses adapted to receive slugs from said die openings and discharge Ithem laterally,

4. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said diev plate, punches slidable on said punch plate and adapted to cooperate with said die openings, resilient means for stripping said punches from the work, and bracing means interposed between said die plate and said base including a bar engaging its upper edge with the underside of said die plate and its lower edge with the upper side of said base and provided on its upper edge with recesses adapted to receive slugs from said die openings and discharge them laterally, said recesses being arranged in staggered relation 'on opposite sides of said bar.

5. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted on` said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate, punches slidable on said punch plate and adapted to cooperate with said die openings, resilient means for stripping said punches from the work,

and bracing means interposed between said die plate and said base including a bar engaging its upper edge-with the underside of said die plate and its lower edge with the upper side of said base and provided on its upper edge with recesses adapted to receive slugs from said die openings and discharge them laterally, said recesses being arranged in staggered relation on opposite sides of said bar and each of said recesses having an inner inclined deflecting surface.

6. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate and provided with guide openings in line with said l`die openings, guiding and stripping tubes arfor raising said punches relative to said'tubes,

and bracing means interposed between said die plate and said base.

3. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a dieplate mounted on said supports in spaced relation to said base and provided with ranged in said guide openings, punches' slidable in said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes relative to said punch plate, resilient means for raising said punches relative to said tubes, and means for locating the work-piece to be perforated on the die plate.

"7. A sheet material perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate, punches slidable on said punch plate and adapted to cooperate with said die openings, resilient means for stripping-said punches from the work. and

'5 means for locating the work-piece to be perforated on the die plate including a brace bar secured to the base and engaging the underside of the die plate and provided with a locating pin ranged in said guide openings, punches slidable J in said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes relative to said punch plate, resilient means for raising said punches relative to said tubes, and means for locating the punch plate relative to the die plate. L

9. A sheet material perforating apparatus comprising a base, spaced'supports resting on said of said rails and provided with die openings, a punch plate having its opposite edge portions secured to the upper surfaces of said rails and Drovided with guide openings in line with said die openings, punching units arranged in said guide openings and cooperating with said die openings, Iand screws securing said die plate to said shoulders and accessible through openings in said punch plate. l

13. A sheet perforating apparatus comprising a die plate having die openings, a punch plate arranged above the die plate and provided .with guide openings in line with the die openings, and

punching units each including a guiding yand stripping sleeve slidable in one oi said guide openings and adapted to` engage its lower end with the top of the work-piece, means to allow the sleeve to slide and to raise it again. a punch slidable in said sleeve and adapted to cooperate with one of said die openings, and resilient means for raising said punch interposed between the upper base, a die plate mounted on said supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate and provided with guide openings in line with said die openings, guiding and stripping tubes arranged in said guide openings, punches slidable vin said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes relative to said punch plate, resilient meansv for raising said punches relative to saidtubes, and means for locating the punch plate relative to the die plate including a plurality of locating pins adapted to be inserted into some of said guide openings and engaged at their ends with some of said die openings.

l0. A sheet vmaterial perforating apparatus comprising a base, spaced supports resting on said base, a die plate mounted onlsaid supports in spaced relation to said base and provided with die openings, a punch plate mounted on said supports in spaced relation to said die plate and provided with guide openings in line with said die openings, guiding and stripping tubes =arranged in said guide openings, punches 'slidable in said tubes and adapted to cooperate with said die openings, resilient means for raising said tubes relative-to said punch plate, resilient means for end of said sleeve and a shoulder on said punch and including a plurality of alternating metal washers and rubber disks through which the punch passes.

14. An apparatus for punching a plurality of holes in sheets of material comprising a punch carrier plate provided with holes in accordance with which a counterpart is to be punched, punching units in said holes, and a die plate provided with apertures to cooperate with said punch units, said die plate being mounted in iixed spaced relation below said punch carrier plate in such manner that work placed between said plates will be n v punched when said punching units are properly actuated toward said die plate.

15. An apparatus for. punching a plurality of holes in sheets of material comprising a punch carrier plate provided with holes in accordance with which a counterpart is to be punched, punchtion below said punch carrier plate in such manner that work placed between said plates will be punched when said punching units are properly actuated toward said die plate, said die plate being supported in spaced relation to the bed of the w press.

raising said punches relative to said tubes, and

means for locating the punch plate relative to the die plate including a plurality of locating pins adapted to be inserted into some of said guide openings and having reduced tips engaging some of said die openings.

11. A sheet metal perforating apparatus comprising a base plate, spaced supporting rails secured thereon, each rail having a supporting. surface on its top side and a rabbet on its inner side forming an intermediate upwardly facing shoulder, a die plat'e having its opposite edge portions secured to the shoulders of said rails and provided with integral die openings, a punch plate having its opposite edge portions secured to the top surfaces of said rails and provided with guide openings in line with said die openings, and

.punching units arranged in Ysaid guide openings and cooperating with said' die openings.

1'2. A sheet metal perforating apparatus comarabbet on its inner side forming an intermediate upwardly 'facing shoulder, a die plate having its I0 prising a base plate, spaced supporting rails each v -16. An apparatus for punching a plurality of holes in sheets of material comprising a. punch carrier plate provided with holes in accordance with which a counterpart is to 'be punched, punching units in said holes, and a die plate provided with apertures to cooperate with said punch units, said die plate being'mounted in xed spaced relation below said punch carrier plate in such manner that work placed between said plates will be punched when said punching units are properly actuated toward said die plate, said die plate being supported in spacedrelation to the bed of the press and being braced at intervals from the bed of the press by supports spaced clear of said die holes.

17. An apparatus according to `claim 15 in which the die plate has only thatportion oi' the plate in. 'the immediate vicinity of each hole hardened.

18. An apparatus according to claim 15 in which the portions of the holes below the upper face of said plate are enlarged to facilitate the removal of slugs punched out of the work and in ,n which only that portion of the plate4 in the immediate vicinity of each hole .is hardened.

opposite edge portions secured to the shoulders 19. Periorating apparatus, including a pair of flat plates spaced apart and held in xed relation to each other and having holes therein, punch units slidably mounted in the holes of one of said plates, the die holes in the other plate being of such size as to cooperate with punches .oi' said punch units, each hole of one of said plates being in axial alinement with a hole of the other plate, whereby the punch units may move toward and into said holes in said plate to perforate the work positioned thereon.

20. A perforating apparatus, including a pair of fiat plates spaced apart and held in xed relation to each other and having holes therein, punch units slidably arranged in the holes of the upper of said plates, the holes in the lower of said plates being of a size to act as dies in cooperation with said punch units, each hole of one of said plates being in axial alinement with a hole in the other plate, whereby punches may be moved relatively to their plate into hole-punching relation to the other plate.

21. A sheet material perforating apparatus comprising spaced supports formed to rest upon the bed of a press, a die plate mounted on said supports in spaced relation to the lower ends thereof and provided with die Aholes in the plate itself, a punch carrier plate secured on said supports in fixed spaced relation to` said base and having guide openings in alinement with the die openings of the die plate, individual punching and stripping units slidably mounted in the guide openings in said punch plate, whereby when work to be perforated is placed upon said die plate, the punches of said punching and stripping units will cooperate with the die holes to perforate the work.

22. A sheet material perforating apparatus, including a pair ofplates provided with holes therein arranged according to the pattern of holes desired in the work, each hole of one plate being in axial alinement with a hole of the other plate, supports cooperating with the edge portions of said plates for supporting said plates, one above the other, in ilxed spaced relation to each other,

individual'punching and stripping units slidably arranged in the holes of the upper plate, means for sliding said punch units upwardly to permit work to be placed between said plates and being slidable downwardly to perforate the work, the holes in thelower plate being formed to cooperate with the punch of said punching units for perforating the work.

23'. A sheet metal perforating apparatus, comy tioned'pl'ate and having holes therein, each hole being in axial alinement with a hole in the lower plate, punch units mounted `lin the holes of the uppergplateland 'including-punches adapted to penetrate: work pla'cedn' said lower plate and en ter into the die holes of the lower plate, said punches beingof "a size to fit the holes in said diepia-te itse1f. y

24;' A'punch unit for use in a perforating de viceMSaid punch-unit including a punch guide n sleeve, a punchslidable lengthwise of said sleeve,

a head for 'saidpunchfav resilient stripper .mem-

ber between said head and said sleeve, said punch unit including alternately arranged rubber disks and rigid washers, for withdrawing the punch out of the work and into said sleeve, and means for supporting some of said washers above said head when said punch becomes shortened.

25. A punch unit for use in a perforating device, said punch unit including a punch guide sleeve, a punch slidable lengthwise of said sleeve, a head for said punch, a resilient stripper member between said head and said sleeve, said punch unit including alternately arranged rubber disks and rigid washers, for withdrawing the punch out of the work and-into said sleeve, a portion of said punch extending through and above said l head, and a cap on the upper end of said punch and having a hole to receive said poi ion of said punch, whereby a rigidwasher may be removed from below said head to above said head and between said head and said washer to compensate for reduction in length of said punch.

26. A punch unit for use in a perforating device, said punch unit including a punch guide sleeve, a punch slidable lengthwise of said sleeve, a head for said punch, a resilient stripper member between said head and said sleeve, said punch unit including alternately arranged rubber disks and rigid washers, for withdrawing the punch out of the work and into said sleeve, a cap for said punch fitting over the head thereof and having a skirt portion into which said head may telescope, whereby when the punch becomes. shortened, washers may be removed from below said head and placed between said head and said cap, to

lower said punch in said sleeve and maintain the same Overall length of said punch unit;

27. A perforating apparatus for use in a press, including supports formed to receive a punch unit carrier plate and a die plate secured in iixed spaced relation to each other, said punch carrier plate having holes therein arranged according to the pattern of holes required in the work, punch units arranged in said holes, said die plate having holes arranged therein so that each hole of one plate is in axial alinement with a hole of the other plate, and means for releasably. securing said plates to said supports, so that said plates may be removed from said supports and replaced by other plates for operating on work of a different kind, said supports with said plates mounted thereon being insertable into and removable from a press without changing the positions of said plates relatively to each other.

28. A perforating apparatus according to claim 27, and including a base plate connecting said supports and spaced below said punch carrier plate and said die plate.

29. A perforating apparatus, according to claim 27 and including a T-slotted base plate on which said supports are removably mounted and on which said supports are adjustable toward and from each other to cooperate with plates of different widths.

30,'A perforating apparatus, including a pair of ilat plates `spaced apart and held in xed relation to each other and having -holes therein, punch units slidably arranged in the holes of the uppery of said plates, the holes in the lower of said plates being of a size to act as dies in cooperationv with said punch units, each hole of one of saidplates being in axial alinement with a hole in theotherplate, whereby punches may be'moved relatively to their plate into hole-punching relation. to the other plate, and stop gages for the c work on the lower of said plates.

31. A perforating apparatus, including la pair of flat plates spaced apart and held in iixed relation to each other and having .holes therein, punch units slidably arranged in th holes of the upper of said plates, the holes in the lower of said plates being of a size toact as dies in cooperation with said punch units, each hole ofone of said plates being in axial alinement with a hole inthe other plate, whereby punches may be moved relatively to their plate into hole-punching relation to the other plate, stop gages for the work on the lower of said plates, and a sight hole in the upper plate through which a stopgage can be seen to facilitate positioning the work in correct relation to the stop gage.

32. A perforating apparatus including a punch carrier plate having a plurality of series of holes ferent types of work -by placing punch units into diierent series of holes in said punch unit supporting plate.

33. An apparatus for punching a multiplicity of holes in sheet material including spaced plates xed to end supports andy carrying a multiplicity o f slidable punches in concentric relation Yabove cooperating Vdie elements in the lower plate and means for varying the lengths of said punch elements for maintaining the over-all length of each punch approximately the same as every other punch.

34. A punch unitfor use in a perforating device, said punch unit including a punchguide sleeve, a

4punch slidable lengthwise of said sleeve, resilient stripper means for retaining said punch in an elevated position relative to said sleeve for withdrawing the punch out of the work and into said sleeve, and means for varying the length of said punch unit for maintaining the overall length of said punch unit to compensate for unequal lengths of other punches in a group due to reductions in length which occur in servicing.

' GEORGE F, WALES.

same apparatus may be used for producing dif'

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