US2325990A - Sheet material punching apparatus - Google Patents

Description

Aug. 3, 1943. G. F. WALES SHEET MATERIAL PUNCHING APPARATUS Filed Nov. 7. 1941 ATTORNEYS Patented Aug. 3, 1943 UNITED STATES PATENT OFFICE SHEET MATERIAL PUNCHING APPARATUS George F. Wales, Kenmore, N. Y. Application November 7, 1941, Serial No. 418,159

17 Claims.

This invention relates to a punchin stamping, blanking or forming apparatus wherebyblanks or slugs of various shapes are cut or stamped out of sheet metal or other sheet material.

A machine of this character is shown in my application for United States patent filed September 27, 1941 and serially numbered 412,626 and the present invention is an improvement of the structure shown in this earlier application.

One of the main purposes of this prior structure was to so organize the blank punching ap paratus that the punch holder, th die shoe, the means for guiding the same relative to each other and the means for stripping the scrap from the punch could remain permanently assembled and attached to parts of the press but permit dies and punches of different sizes and shapes to be assembled with the die shoe, punch holder and associated parts, without taking these mountings out of the press and without requiring any reconstruction or alteration in the mountings, thereby reducing the cost and facilitating the operations of producing blanks of different sizes and shapes.

The object of the present invention is to provide an apparatus of the same general character as this prior device but of simpler construction and so organized that the same forms a complete self-contained unit which has no parts requiring attachment to any part of a press, such as the vertically movable ram of the latter, but can be freely placed on the bed of the pres and under its ram when it is desired to utilize the punching apparatus and also freely removed therefrom when not required or for convenience in changing the punch and die for any reason.

In the accompanying drawing:

Fig. 1 is a vertical'section of one form of sheet metal punching apparatus embodying this invention taken on line |-l, Fig. 2 and showing the punch and die closed.

Fig. 2 is a horizontal section of the same taken on line 2-2, Fig. 1 and showing the die and punch closed.

Fig. 3 is a fragmentary vertical section taken on line 3-3, Fig. 2.

In the following description similar reference characters indicate like parts in both figures of the drawing:

The numeral l represents a lower stationary support of the punching or stamping press such as a base, table, bolster or bed and II the ram thereof which is arranged above the base as in the usual and well known construction of presses of this type now in common use. The numeral I2 represents the die or die steel provided with a die opening I3 and M the punch arranged above the die adapted to cooperate with said opening for cutting blanks or slugs Hi from a sheet metal workpiece it which latter in the present case has the form of a strip. The cutting edges of the die and punch are of such form that the blank which is produced between the die and punch is of corresponding shape. This blank may be of any desired contour to suit the purpose for which the same is intended that shown in the drawing, for example, being generally in the form of the letter L, as shown by dotted lines in Fig. 2. The die preferably has the form of a horizontal plate which is arranged within the lower part of a vertical opening I! formed in a shoe holder or frame l8 resting on the upper side of the support or base Ill. The base i0 is normally stationary and the die is backed by a backing plate l9 arranged within the holder opening I! between the upper side of the base I0 and the underside of the die plate, as shown in Fig. 1.

That part 20 of the press bed below the die holder l8 forms a filler which is made separate from the main part of the press bed and removably supported in an opening 2| in the bed by a flange 22 on the periphery of the fi ler engaging with an upwardly facing shoulder 23 in the bore of the opening 2|. The filler 2|] and the backing plate I!) are provided respectively with registering discharge openings 24, 25 which are in line with the die opening I 3 and may be of a form corresponding to the blanks or slugs l5 which are cut from the workpiece by the punch and die and permit these slugs to escape downwardly through the apparatus.

The punch is movable vertically toward and from the die and mounted on a vertically movable punch holder which comprises a lower horizontal punch plate 26 which is guided ior vertical movement by engaging its periphery in the vertical upper part oft-he opening I! in th die shoe or holder I8 and carrying the punch on its underside, a hollow bracket or ring 21 having its lower part guided in the opening I! of the die holder and connected by bolts 28, or otherwise, with the marginal part of the punch plate 26, and a horizontal presser head or head plate 29 arranged above the die holder and bracket 21 and connected with the upper end of the latter'by screws 30 or other suitable means. The punch is detachably connected with the punch holder by means consisting preferably of a long vertical screlw 3| passing through the central parts of the punch plate and head plate and connecting with the central part of the punch and by a plurality of short vertical screws 32 passing through the punch plate and connecting with different parts of the punch at a distance from the central part thereof.

When the punch and punch plate are comparatively small the bracket 27 of the punch holder is made suificientl strong to hold the punch plate in place while the punch is producing a cutting operation in cooperation with the die, but when the punch and punch plate are comparatively large a bracing or reenforcing member 33 is interposed between the central parts of the punch plate and presser plate, which member preferably has the form of a Sp c sleeve or tube which surrounds the central screw 3! connecting the punch plate and the head plate.

The punch holder when free is yieldingly held in its elevated position so as to clear the space between the punch and die by spring elevating means which consist preferably of a plurality of elevating springs 3% which are arranged in an annular row between the marginal parts of the die holder i8 and head plate 29 and each of which is held against lateral displacement by means which include a vertical retaining pin 35 arranged within the respective spring and secured at its lower end to the upper side of the die holder.

The workpiece to be perforated is fed to the working position between the die and punch and removed therefrom through slots or openings 36, 37 formed on diametrically opposite sides of the die holder flush with the upper side of the die.

While this punching mechanism is resting on the base or bed of the press and the ram is elevated, the punch holder is raised by the springs 34 and forms a gap between the die and punch. While the parts are in this position the operator slips the sheet of metal or other workpiece it through one or both of the slots 36, 31 in the die holder and across the gap between the die and punch after which the ram descends and by engagement with the head plate causes the same to descend with bracket 21 and other parts of the punch holder and engage the workpiece so as to cut a blank or slug i therefrom, as shown in Fig. 1, which blank is discharged downwardly through the openings in the die, backing plate and filler plate. Upon raising the ram the punch holder together with the punch and associated parts, is also raised by the elevating springs 34, thereby clearing the space between the die and punch preparatory to shifting the workpiece and performing another punching operation.

Stripping means are provided for removing from the outer side of the punch the scrap of the work which adheres thereto after severing a blank from the workpiece which stripping means may be variously organized but as shown in Figs. 1 and 2, are constructed as follows:

The numeral 38 represents the vertical bodies or stems of a plurality of stripping pins which are adapted to slide'vertically in guide openings 39 in the punch plate 26 and adapted to bear at their lower ends against the upper side of the scrap of the workpiece and provided at their upper ends with enlarged heads 40 forming stop shoulders which are adapted to engage with the upper side of the punch plate for arresting the downward movement of the stripping pins when the lower ends of the same are flush or substantially so with the underside or face of the punch. Within the chamber formed by the hollow bracket and between the punch plate and head plate is arranged a vertically movable horizontal stripping plate til which bears against the heads 30 at the upper ends of the stripping pins. This stripping plate is provided centrally with a clearance opening 32 which receives the central reenforcing member 33. Spring means are provided which tend constantly to move the stripping plate and the stripping pins downwardly which means preferably comprise a plurality of helical springs 36 which are placed under an initial compression and engaged at their lower and upper ends, respectively, with the marginal parts of the top of the stripping plate ti and the underside of the head plate 29. Downward movement of the stripping plate is arrested by stop means consisting preferably of a lower stop tube 63 secured at its lower end to the top of the stripping plate and having an internal downwardly facing stop shoulder 65, and an upper stop rod 46 secured at its upper end to the underside of the presser plate and having a head il at its lower end arranged within the stop tube 63 and adapted to engage with the shoulder d5 thereof. Astop tube and rod of this character are arranged in each of the elevating springs 36 so that the same is held against lateral displacement but is free to expand and contract lengthwise.

While the ram and the punch holder are elevated the stripper plate is depressed by the springs so that the lower ends of the stripper pins 38 project below the underside or face of the punch and the heads as of these pins engage with the top of the punch plate 2%.

While the punch is thus elevated, the workpiece it is placed between the cooperating faces of the die and punch and then the punch holder and parts carried thereby are moved downwardly with a working stroke by the rain of the press engaging with the top of the head plate 29. During the first part of the descent of the punch holder and associated parts, the lower ends of the stripping pins 38 engage with the upper side of the workpiece immediately around the periphery of the punch and clamp the same against the top of the die, and thereafter the punch engages the top of the workpiece and causes a blank o slug it to be cut out of the workpiece by cooperation of its cutting edge with that of the die, as shown in Fig. 1. During the last part of the descent of the punch, the stripping pins and stripping plate are at rest, whereby the heads ii or the stop rods t6 are carried downwardly away from the shoulders 35 of the stop tubes 63 and the stripping springs 36 are further compressed between the stripping plate t! and the head plate 29.

During the first part of the subsequent up ward movement "of the punch holder and aesc= ciated parts the stripping pins are at rest and pressed by the springs N against the scra at.

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the workpiece until the heads 6? of rods lit are engaged by the shoulders 66 oat stop tubes 48, after which the punch, stripping pins and parts carried by the punch holder move upwardly in unison to the end of the upward stroke of the same. It follows from this thatthc punch is first withdrawn from the die and the scrap is held down on the die until the punch has effected the first part of its upward mcvc ment, whereby the scrap is, stripped from the :punch and remeinson theme, preparatory presenting another part of the workpiece to the working position.

The openings in the punch plate 26 which receive the bodies of the punch fastening screws 3|, 32 and the stripping pins 38 are preferably of the same size, or substantially so, and thus permit any one of these openings to receive either the body of a punch fastening screw or the body of a stripping pin. Openings of this character are distributed in closely-spaced relation over the entire area of the punch plate and thus enable certain of these openings to be used for fastening the punch to the punch plate and others to be used to guide stripping pins in accordance with the shape of the particular punch and die which are employed for cutting blan from a workpiece.

For example, when using a cylindrical punch of comparatively small diameter, only the central fastening screw 3| and a plurality of other screws may be arranged in an annular row immediately around this central screw and engaged with the corresponding openings in the punch for securing the punch to the punch plate, and a plurality of stripping pins 38 may be arranged in an annular row around the periphery of the punch and engaged with the corresponding openings in the punch plate for engaging the scrap of the workpiece adjacent to the outer side of the line on which the blank is cut from the workpiece, while the remainder of the selectable openings 39 in the punch plate are left vacant.

When using a punch which is non-circular such, for example, as the L-shaped punch [4 shown in Fig. 2, this punch is fastened to the punch plate by a plurality of fastening screws 3i, 32 one of which, 3|, is arranged centrally of the punch plate and the others, 32, of which are arranged generally in the form of the letter L and placed in the appropriate openings in the punch plate which most closely approximate the contour of the L-shaped punch, and stripping pins 38 are placed around the outline of the L- shaped punch and engaged with the most suitable guide openings 39 in the punch plate so as to enable the lower ends of the stripping pins to engage the scrap of the workpiece immediately around the punch and strip this scrap therefrom upon moving the punch away from the correspondingly shaped die.

It will thus be apparent that by selecting the appropriate openings in the punch plate to receive screws for fastening a punch of a particular shape thereto and also selecting appropriate openings in the punch plate to receive stripping pins and arrange them to fit the contour of the respective punch, that this enables all parts of the dieand punch mounting to be used in connection with various shapes of dies and punches, and that it is only necessary to rearrange the punch fastening screws and the stripping pins when changing from one shape of punch and die to another shape of punch and die. The cost of doing work of this character, particularly when running a small order of any particular form of blank, is therefore materially reduced due to the rapidity with which the dies and punches may be set up and no new parts are required for mounting dies and punches.

Means are provided for alining the punch and die so that the same will always cooper-ate perfectly, which means preferably comprise two upright alining pins 48 arranged on opposite sides of the path of the workpiece I6, each of these pins having its lower end tightly secured in an opening I90 in the backing plate I! and having an upper tapered end which slidably engages with an opening, part I of which is formed in the outer edge of the stripper plate 4| and part 2' of which is formed in the inner side of the bracket 21, while the intermediate part of the respective alining pin passes through an opening l2l in the die plate I2 and also through an opening 238i in the punch plate 28, as best shown in Fig.

Various means may be employed for preventing the backing plate, die plate, punch plate and the parts associated therewith from turning in the holder is such, for example, as the set screw l8l mounted on the lower part of the holder and engaging with the adjacent edge of the backin plate I9, as shown in Fig. 3. By these means the punch is'accurately guided with absolute accuracy in its movement toward and from the die and the punch and stripping means may be removed from the holder and reassembled therewith without disturbing the correct register of the punch and die.

When it is desired to' remove the punching unit from the holder 18 preparatory to changing the punch and die the head plate 29 is grasped and lifted from the holder together with the bracket, punch plate, punch, stripping plate, stripper pins, fastening screws, springs and parts associated therewith. After the punch unit has been thus removed from the holder l8 the screws 28 and '1 3! may be readily removed for eflecting a, rapid change of the punch I4 and stripping pins 38, 48. The die plate i2 may now be lifted out of the holder by reaching into the opening [1 therein and replaced by a die plate having a difierent form of die opening and in like manner the backing plate I9 and the guide posts or alining pins 48 may be also removed from the holder l8, if desired.

When the punch unit is removed from the holder and associated parts the punch plate 26 is used as -a jig or template'for drilling guide post holes |2l in the new die plate in conformity with the guide post, holes 26! of the punch plate. After this drilling of .the guide holes l2! has been done the die plate having the new die opening therein is assembled with .the backing plate l9 so that the pins or posts 48 of the latter engage with the holes l2! of the die plate and the punch plate has its holes 26| engaged by the guide posts or pins and its underside resting on top of the die plate, and the new punch engaging with the new die opening but loosely mounted on the punch plate. After these parts have been thus assembled in proper alinement the fastening screws 3 I, 32 are tightened for securing .the punch in place and thus ensuring perfect register of the punch with the die opening.

These parts are then separated, the punch plate is secured to the bracket 21 by the screws 28, the backing plate and die plate are dropped into the holder opening l1, and the openings 26| while the parts are disassembled and accurately reassembled conveniently and expeditiously after the change in the punch and die elements has been eilected.

The above described means for guiding or alining the die plate and punch plate by means of upright posts or pins mounted on a base plate and projecting upwardly through registering openings in the die plate and punch plate are substantially the same as the corresponding parts shown in my earlier application Ser. No. 412,626, filed September 27, 1941.

It will be noted that when the ram of the press is raised the punch plate, punch, stripping means and the means which carry the same float freely on the holder on which the die plate, backing plate and guiding elements are mounted,

A punching apparatus made in accordance with this invention forms a complete operative unit or assembly which does not require attachment to any part of a press for operating the same but can be used by simply placing the same freely between the stationary bed or base of the press when required and then removed therefrom when no longer required.

It will be apparent from the foregoing that the construction of this punching apparatus is very simple, strong and compact, that the same is not liable to get out of order and that the same is eflicient in operation and can be readily and easily changed for producing cut or stamped blanks of diiferent sizes or shapes, and thereby enable work of this character to be done more economically.

Although the head 41 of the solid stop rod 46, is shown in Fig. 1 as fitting closely in the tubular stop 43, this fit is comparatively loose so as to avoid the formation of an air cushion in this tubular stop.

I claim as my invention:

1. An apparatus for punching sheet material, comprising a lower shoe provided with a vertical guide opening, a die mounted in the lower part of said guide opening, a vertically movable punch holder having a lower punch plate arranged in the upper part of said guide opening, a bracket connected at its lower end with the punch plate, a head plate connected with the upper end of said bracket, and a punch mounted on the punch plate and adapted to cooperate with said die.

2. An apparatus for punching sheet material, comprising a lower shoe provided with a vertical guide opening, a die mounted in the lower part of said guide opening, a vertically movable punch holder having a lower punch plate arranged in the upper part of saidguide opening, a bracket connected at its lower end with the punch plate, a head plate connected with the upper end of said bracket, a punch mounted on the punch plate and adapted to cooperate with said die, and spring means for lifting said holder interposed between the marginal parts of said die shoe and the head plate of said punch holder.

3. An apparatus for punching sheet material, comprising a lower die shoe provided with a die, an upper punch holder guided on the die shoe and provided with a punch adapted to cooperate with the die, stripper members guided on the punch holder and adapted to engage the scrap around the punch, spring means for yieldingly holding the punch holder in its elevated position, and spring means for yieldingly holding said stripper members in a depressed position.

4. An apparatus for punching sheet material, comprising a lower die shoe having a vertical guide opening; a die mounted in said opening; a vertically movable punch holder having a punch plate arranged within the upper part of said guide opening, a hollow bracket connected at its lower end with said punch plate, and a head plate connected with the upper end of said bracket; a punch mounted on the underside of said punch plate and adapted to cooperate with said die, a reenforcing member arranged between the central parts of said punch plate and head plate, and a screw connecting said punch, punch plate and head plate and passing through said reenforcing member.

5. An apparatus for punching sheet material, comprising a lower die shoe having a vertical guide opening; a die mounted in said opening; a vertically movable punch holder having a punch plate arranged within the upper part of said guide opening, a hollow bracket connected at its lower end with said punch plate, and a head plate connected with the upper end of said bracket; a punch mounted on the underside of said punch plate and adapted to cooperate with said die, and stripper means including a plurality of stripping pins guided on said punch plate and adapted to engage their lower ends with the scrap of the workpiece, a stripping plate arranged within said hollow bracket and engaging with the upper ends of said pins, and spring means for holding said pins in a depressed position and interposed between said stripping plate and head plate.

6. An apparatus for punching sheet material. comprising a lower die shoe having a vertical guide opening; a die mounted in said opening; a vertically movable punch holder having a, punch I plate arranged within the upper part of said guide opening, a hollow bracket connected at its lower end with said punch plate, and a head plate connected with the upper end of said bracket; a punch mounted on the underside of said punch plate and adapted to cooperate with said die, and stripper means including a plurality of stripping pins guided on said punch plate and adapted to engage their lower ends with the scrap of the workpiece, a stripping plate arranged within said hollow bracket and engaging with the upper ends of said pins, spring means for holding said pins in a depressed position and interposed between said stripping plate and head plate, and stop means for limiting the downward movement of said stripping plate including a stop tube and stop rod secured respectively to said plates and said tube being provided with a stop shoulder and said stop rod being provided with a stop head adapted to engage said stop shoulder.

7. A stamping apparatus comprising a holder having an opening, a backing plate arranged within the lower part of said opening and having a guiding element, a die plate having a die opening and. resting on said backing plate and cooperating with said guiding element, a punch cooperating with said die opening, a punch plate carrying said punch and movable in the upper part of said holder opening and cooperating with said guiding element for registering said punch with said die opening, and stripping means associated with said punch for removing the workpiece therefrom, said punch plate, punch and stripping means being free to float on said holder when in their raised inoperative position and said die plate and punch adapted to be changed withoughchanging other elements associated there- W1 8. A stamping apparatus comprising a stationary support, a ram movable toward and from the support, a holder mounted on said support'and provided with an opening, a backing plate arranged in the lower part of the opening in said holder and cooperating with saidopening and having a guiding element, a die plate resting on said backing plate and cooperating with said guiding element and engaging the same and having a die opening, a punch adapted to cooperate with said die opening, a punch plate cooperating with said holder and carrying said punch and movable in the upper part of the opening in said holder and cooperating with said guiding element, stripper means selectively associated with said punch plate, and resilient meansengaging said stripper means.

9. A stamping apparatus comprising a stationary support, a ram movable toward and from the support, a holder mounted on said support and provided with an opening, a backing plate arranged in the lower part of the opening in said holder and having a guiding element, a die plate resting on said backing plate and cooperating with said guiding element and having a die opening, a punch adapted to cooperate with said die opening, a punch plate carrying said punch and movable in the upper part of the opening in said holder and cooperating with said guiding element, stripper means selectively associated with said punch plate, resilient means engaging said stripper means, and lifting means resting on said holder and adapted to raise said punch plate, punch, stripper means and resilient means to permit removal of stamped blanks from between the die plate and punch.

10. The hereindescribed method of stampin blanks in a press consisting in providing a selfcontained blanking device having a holder, removably mounting in an opening on said holder a. punch plate, selectively and detachably mounting on said punch plate variously shaped punch elements independently of other parts of the apparatus, selectively mounting a die element in the opening on said holder in operative relation to the respective punch element, and providing rigid guiding means for maintaining said punch element and die element in proper register.

11. A blanking apparatus for sheet material comprising a holder-having a vertically bored cylindrical opening, a horizontally slotted passageway extending through two walls and intersecting said cylindrical opening midway between th bottom and top surfaces of said holder, a backing plate in the lower portion of said opening provided with guide means, a die member on said backing plate guided by said guide means, the top face of said die member being approximately flush with the bottom of said slotted passageway, said die member being provided with an opening the shape of the desired blank and said backing plate being provided with an opening through which said blank may pass and a floating plunger assemblage in the upper portion of said cylindrical opening comprising a plunger guided in said opening, means for retaining said plunger in an elevated position, said plunger being provided with an internal stripper plate, means for yieldingly retaining said stripper plate so that the lower face of said plate is in recessed relation to the face of the lower rim of said plunger, said plunger assemblage being capable of being freely removed from said holder to empty said upper cylindrical opening to provide access to said backing plate and diememher for removal of the same from said cylindrical opening, and replacement of said backing plate and die member with other backing plates and die members selectively, said plunger assemblage being provided with means for accommodating a punching assemblage including a universal mounting plate provided with a pattern of holes through which means for attaching companion punch elements for said die members may be inserted and through which means for stripping the work from said punch elements may be'selectively inserted around said punch lements including a plurality of shoulder pins having heads of the proper length to fit into said recess so as to contact the lower face of said stripper plate and the upper face of said mounting plate when said mounting plate is attached to the lower part of said plunger, said shoulder pins extending through said mounting plate and having the lower faces flush with, or extended beyond, the cutting face of said punch element, to cause longitudinal pressure to be applied through said pins by said stripper plate when said punch element penetrates said material, said punch element being guided in proper relation to said die opening by means of said die member guide means cooperating with companion guide means in said mounting plate and means for preventing said punch elements and die elements from turning in said holder.

12. A blanking apparatus for sheet material comprising a holder having a vertical opening, a horizontal passageway intersecting said opening, a backing plate in the lower portion of said opening provided with guide means, a die member on said backing plate guided by said guide means, the top face of said die member being below the top surface of said passageway, said die member being provided with an opening the shape of the desired blank and said backing plate being provided with an opening through which said blank may pass, a floating plunger assemblage in the upper portion of said vertical opening comprising a plunger guided in said opening, means for retaining said plunger in an elevated position, said plunger being provided with an internal stripper plate, means for yieldingly retaining said stripper plate so that the lower face of said plate is in recessed relation to the face of the lower rim of said plunger, said plunger assemblage being capable of being freely removed from said holder, to provide access to said the member for removal of same from said vertical opening and replacement of same with a different die member, said plunger assemblage being provided with means for accommodating a punching assemblage including a universal mounting plate provided with a pattern of holes through which means for attaching a companion punch element for said die member may be inserted, and through which means for dowelling said punch to said mounting plate may be inserted and through which means for stripping the work from said punch element may be selectively inserted around said punch element including a plurality of shoulder pins having heads of the proper length to fit into said recess so as to contact the lower face of said stripper plate and the upper face of said mounting plate when said mounting plate is attached to the lower part of said plunger, said shoulder pins extending through said mounting plate and having the lower faces flush with, or extended beyond, the cutting face of said punch element, to cause longitudinal pressure to be applied on said material through said pins by said stripper plate when said punch element penetrates said material, said punch element being guided in proper relation to said die opening by means of said die member guide means cooperating with companion guid means in said mounting plate and means for preventing said punch element and die element from turning in said holder.

13. A blanking apparatus for sheet material comprising a holder having a vertical opening, a horizontal passageway intersecting said opening, a base in the lower portion of said opening provided with guide means, a die member on said base guided by said guide means, the top face of said die member being below the top surface of said passageway, said die member being provided with an opening the shape of the desired blank and said base being provided with an opening through which said blank may pass, a floating plunger assemblage in the upper portion of said vertical opening comprising a plunger guided in said opening, means for retaining said plunger in an elevated position, said plunger being provided with an internal stripper plate, means for yieldingly retaining said stripper plate so that the lower face of said plate is in recessed relation to the face of the lower rim of said plunger, said plunger assemblage being capable of being freely removed from said holder, to provide access to said die member for removal of same from said vertical opening and replacement of same with a different die member, said plunger assemblage being provided with means for accommodating a punching assemblage including a universal mounting plate provided with a pattern of holes through which means for attaching a companion punch element for said die member may be inserted and through which means for dowelling said punch to said mounting plate may be inserted and through which means for stripping the work from said punch element may be selectively inserted around said punch element including a plurality of shoulder pins having heads of the proper length to fit into said recess so as to contact the lower face of said stripper plate and the upper face of said mounting plate when said mounting plate is attached to the lower part of said plunger, said shoulder pins extending through said mounting plat and having the lower faces flush with, or extended beyond, the cutting face of said punch element, to .cause longitudinal pressure to be applied on said mate rial through said pins by said stripper plate when said punch element penetrates said material, said punch element being guided in proper relation to said die opening by means of said die member gu de means cooperating with companion guide means in said mounting plate and means for preventing said punch element and die element from turning in said holder.

14. A blanking apparatus for sheet or strip material comprising a holder having a vertical opening, a horizontal passageway extending through two walls and intersecting said opening, a base in the lower portion of said opening provided with guide means, a die member on said base guided by said guide means, the top face of said die member being below the top surface of said passageway, said die member be ng provided with an opening the shapeof the desired blank and said base being provided with an opening through which said blank may pass, a plunger assemblage in the upper portion of said vertical opening comprising a plunger guided in said opening, means for retaining said plunger in an elevated position, said plunger being provided with a stripper plate, means for yieldingly retaining said stripper plate, means for accommodating a punching assemblage including a universal mounting plate provided with means for attaching a companion punch element for said die member and means for stripping the work from said punch element, said punch element being guided in proper relation to said die opening by means of said die member guide means cooperating with companion guide means in said mounting plate and means for preventing said punch element and die element from turning in said holder. 4

15. A blanking apparatus for sheet or strip material comprising a holder having a vertical opening, a horizontal passageway intersecting said opening, a base in the lower portion of said opening provided with guide means, a die member on said base guided by said guide means, the top face of said die member being below the top surface of said passageway, said die member being provided with an opening the shape of the desired blank and said base bein provided with an opening through which said blank may pass, a plunger assemblage in the upper portion of said vertical opening comprising a plunger guided in said opening, means for retaining said plunger in an elevated position, means for detachably fastening a punching assemblage to said plunger including a universal mounting plate provided with means for attaching a companion punch element for said die member and means for stripping the work from said punch element, said punch element being guided in proper relation to said die opening by means of said die member guide means cooperating with companion guide means in said mounting plate and means for preventing said punch element and die element from turning in said holder.

16. The hereindescribed method of organizing a blanking apparatus for sheet material, consisting of an operating unit, to which may be adapted singly, diilerent punch and die elements, to out various shapes of blanks, said operating unit consisting of a base holder having a vertical opening, internal die element and punch mounting plate guide means, said means consisting of guide pins mounted in the base of the holder and projecting upward inside of said vertical opening, a plunger assemblage guided for reciprocal motion in the upper portion of said opening, said assemblage comprising a plunger, means for retaining said plunger in an elevated position, stripper actuating means in said plunger, a multi-apertured punch mounting plate, detachably mounted to the lower portion of said plunger, said plunger assemblage being freely removable from said vertical opening in said holder, to provide access to the lower portion of said opening and to said punch mounting plate, and then detaching said mountin plate from said plunger, aligning the guide pin openings in said mounting plate with companion guide pin openings in the die element selected, the cuttin face of said die element being placed against the outer face of said plate, and then placing the companion punch element into the opening in said die element with the cutting face farthest away from the outer face of said mounting plate, said punch element being the exact size of the die element opening at the top side which is adjacent to the die member cutting edges when said die element and punch element are placed in this position on said mounting plate, said punch element being smaller at its cutting face by an amount satisfactory for proper clearance between punch and die, then inserting bolts through said apertures in said mounting plate into the threaded openings in said punch element and bolting said punch element tightly to said plate, then inserting stripping pins through other-of said apertures surrounding said punch element, attaching said mountin plate, stripper pins, and punch element assembly t the lower part of said plunger, placing said die element in said vertical opening in register with said guide pins, with its cutting edge up and then returning said plunger assemblage to said vertical opening in said base holder, in such manner that the guide pin openings in said punch plate register with the same guide pins as said die element, to assure perfect register between the contour of the punch element and the companion opening in said die element, said holder being provided with suitable openings for the insertion of the material, ejection of the blanks, and removal of the scrap.

17. The hereindescribedmethod of organizing a blanking apparatus for sheet material consisting of an operating unit with which may be used different punch and die elements to out various blank shapes, said operatingunit consisting of a base holder having a vertical opening with internal die member guide means, a plunger assemblage guided for reciprocal motion in the upper portion of said opening, said assemblage comprising a plunger, means for retaining said plunger in an elevated position, stripper means in said plunger, a perforated punch mounting plate detachably mounted to the lower portion of said plunger, said plunger assemblage being freely removable from said vertical opening to provide access to the lower portion of said opening and to said punch mounting plate and then detaching said mounting plate from said plunger, aligning guide means in said plate with companion guide means in the die member selected, the cutting face of said die member being placed against the outer face of said plate, and then placing the companion punch element into the opening in the die element with the face opposite the cutting face against the outer face of said plate, then inserting bolts through said perforations in said mounting plate into the threaded openings in said punch member and bolting said punch tightly to said plate, then inserting stripping pins through other of said perforations surrounding said punch, attaching said mounting plate, stripper, and punch element assemblage to the lower portion of said plunger, placing said die member in said vertical opening in said base holder with its cutting edge up and in engagement with said internal die member guide means and then returning said plunger assemblage to said vertical opening in said base holder in such manner that aid internal die member guide means also engages said punch mounting plate to assure perfect alignment between the contour of said punch element and the companion opening in said die element said holder being provided with suitable openings for material insertion, blank ejection, and scrap removal.

GEORGE F. WALES.

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