US2268787A - Sheet metal perforating apparatus - Google Patents

Description

Jan. 6, 1942. G F 'wALEg 2,268,787

SHEET METAL PERFORATING APPARATUS Filed Feb. 1'7, 1941 2 Sheets-Sheet 1 2 W7 /7 /777/7 fl 2 r 26 28 1 Z; ATTORNEYS Jan. 6, 1942. F WALES 2,268,787

SHEET METAL PERFORATING APPARATUS Filed Feb. 17, 1941 2 Sheets-Sheet 2 56 25 22 I Z? 5 F' .4. Q Z; v 6/ 5 [13% @333; 33;} Z v 55 W Z L 9.5 55% 476$ 4 2$ 4 46/ 47WA iZ/ wwyi 1 W %IZEGTOR ATTORNEYS Patented Jan. 6,- 1942 2,268,787 1 SHEET METAL PERFORATING APPARATUS George F. Wales, Bufialo, N. Y.

Application February 17, 1941, Serial No. 379,185

6 Claims.

This invention relates to a punching unit for sheet material perforating apparatus of the character shown in my Letters Patent of the United States No. 1,955,866 granted April 24, 1934.

In the punching units shown in this prior patent the lower or bit ends of the punch bodies were guided solely-in the lower ends of the guide sleeves and this involved considerable cost when changing from one size punch to another, inasmuch as such changes necessitated disassembling the punch, its guide -sleeve and stripping elements of the unit, substituting a guide sleeve of the required size to suit the new punch body and reassembllng-of the same with the stripping elements or having individual stripping guide assemblies for each size punch.

One of the objects of this invention is to provide a punch unit of this character in which 'nearly all of the stripping elements can be used with all sizes of punches and which requires only the substitution of one punchfor another and the use of a corresponding guide button stripper whenever it is necessary to use a punch of a different size, thereby effecting a considerable cost in equipment.

Another object of this invention is to provide improved means for connecting the heads-to the bodies of punches and also to improve the means and method of connecting the lower spring sup porting collars of the stripping devices to the guide sleeves of the punches.

In the accompanying drawings:

Fig. 1 is a sectional side elevation of a sheet metal perforating apparatus embodying one'form of this invention.

Fig. 2 is a top plan view of the same.

Fig. 3 is a fragmentary horizontal section, taken on line 3-3, Fig. 1'.

, Fig. 4 is a vertical section showing the manner of securing the head to the body of the punch in accordance with this invention.

Figs. 5, 6 and 7 are vertical sections showing various stages in the use of the method and apparatus for securing the lower spring supporting collar of the stripping device to the punch guide sleeve in accordance with this invention.

Fig. 8 is a fragmentary vertical section showing a slightly different form of the invention compared with that shown in Fig. 1.

In the following description similar characters of reference indicatelike parts in the several figures of the drawings.

The punching unit which embodies the present invention may be used in connection with other parts of a sheet metal perforating apparatus (Cl. 164-124) I 'which may vary in their detail construction but,

as shown-in Figs. 1, 2. and 3, these other parts include a holder having a lower base or shoe l which is provided on its upper side'with a die seat II and a slug chute l2 leading from the underside of this seat to one side of the base and an upper horn or head l3 which is separated from the base by a gap l4 and provided above the die seat with a vertical guide opening ii of cylindrical form. The holder is supported by a templet plate l6 which rests on the bed 9 of the press and is secured to the underside of the holder by a screw I1 and held against turning horizontally thereon by a locating screw I 8 arranged on the underside of the holder and engaging with the opening IS in the templet plate. Above the holder is arranged a vertically movable ram 20 which may be raised and lowered by any suitable means. The seat ll receives a perforating die 2|, the upper side of which is preferably'arranged slightly above the surface of the base of the holder and the same is provided with the usual die opening 22 which receives the slug removed from the sheet material workpiece'23, such as sheet metal, during the operation of perforating the same and delivers the same to the discharge chute '-I2.

The preferred form of punching unit which cooperates withthe die for perforating the workpiece and strips the latter from the punching unit after the perforating operation is complete may be variously constructed in accordance with this invention, but as shown in Figs. 1, 2 and 3 the same is constructed as follows:

The numeral 24 represents the vertical body of the punch, the lower end of which forms a cutting bit 25 which cooperates with the upper edge of the punching opening 22 in the die 2| for removing a slug from the workpiece during the operation of forming a hole in this workpiece. At its upper end the punch body is provided with a head 26 which, together with the punch body, are adapted to be engaged by the ram 20 and moved downwardly thereby causing the bit to perforate the workpiece.

. annular grooves or recesses 21, for example, two

grooves as shown in Figs. 1 and 4. The grooved part of this body is arranged .within a central opening 28 inthe punch head and metal'from the bore of the opening in the head is displaced in- The union of the punch body and head in this 5 manner may be effected, as shown in Fig. 4, by placing the punch body downwardly in the socket 30 of an upright holder 3| so that the bit is spaced from the bottom of this socket and the upper end of the body projects above this holder,

then placing the ring-shaped punch head 29 upon the holder 3| so the opening or bore in the head receives the punch body and the upper sides of the punch body and head are flush, and then subjecting the metal of the head immediately around the bore thereof to a squeezing or swaging operation of an annular swaging bead 32 arranged on the upper side of the holder 3| and engaging the underside of the punch head concentrically with its axis and an annular swaging 2 bead 33 arranged on the underside of a former 34 and engaging the upper side of the punch head concentrically with its axis. Upon moving the holder 3| and former 34 toward each other between the bed 35 and the ram 36 of a press, the

lower and upper swaging beads 32, 33 displace a part of the metal of the head inwardly from the bore of the same into engagement with the grooves-or recesses 21 of the punch body and thus securely interlock and connect the same.

wardly during the operation of swaging the beads 40 29 from the head into the grooves 21 of the body. If desired the position of the holder 3|, forming die 34, punch body 24 and punch head 26 may be reversed between the bed and ram 36 particularly when the punch body fits loosely in the a holder and punch head.

The numeral 31 represents a guide sleeve which is arranged centrally within the guide opening i5 of the punch mechanism holder and in which the body of the punch slides vertically. The

upper part of the guide sleeve is arranged within an upper collar or guide ring 38 which slides vertically within the upper part of the holder guide opening IS. The upper end of the upper collar engages with the underside of the punch head 26 55 and its lower end is free to slide downwardly on the guide sleeve an undetermined extent but the extent of upward movement of the upper collar relative to the guide sleeve is limited by a downwardly facing annular stop shoulder 39 formed 0 on the upper part of the periphery of the guide sleeve and an upward facing annular shoulder 40 arranged internally on the lower part of the upper collar and engaging the shoulder 39 of the guide sleeve. 05

The numeral 4| represents a collar secured to the periphery of the guide sleeve at the lower end thereof. Between the upper and lower collars 38 and 4| a stripper spring 42 of helical form surrounds the guide sleeve and bears at 70 its upper and lower ends against the upper and lower collars, respectively, and is preferably under an initial tension when the upper and lower collars are spaced apart their fullest extent.

Various means may be employed for connect- 75 When the punch body fits 35 ing the lower collar with the guide sleeve but those shown in the drawings are adapted to produce a permanent connection between the guide sleeve and the lower collar and for this purpose the lower collar and the guide sleeve are connected in the following manner:

Initially the guide sleeve is provided on the lower part of its periphery with a downwardly facing annular shoulder 43 and within the lower part of its bore with an annular temporary rib or bead 44, as shown in Fig. 5. The bore of the lower collar has its lower part enlarged so as to form a downwardly facing annular shoulder 45 within this collar. The guide sleeve, upper and lower collars and the spring together form elements of the means whereby the 'sheet of metal and the punch are separated or stripped from one another after the operation of a hole in the sheet of metal has been completed. Preparatory to permanently assembling these stripping elements the same are first stacked loosely in a vertical column by placing the lower collar on a support block or anvil 46 which rests on the bed 41 .of a press and provided with a vertical opening 48 in line with the bore of the lower collar, as shown in Fig. 5, then placing the spring while in a wholly expanded or relaxed'condition with its lower end in engagement with the top of the lower collar, then placing the upper collar withits underside in engagement with the upper end of the spring, and then inserting the guide sleeve downwardly through the upper collar and the spring until the shoulder 39 of the guide sleeve engages with the shoulder 40 of the collar, at which time the lower end of the guide sleeve projects partway into the upper small part of'the bore of the lower collar and the lower external shoulder 43 is spaced upwardly from the upper side of the lower collar, as shown in Fig. 5. After the stripper elements have been thus loosely stacked they are subjected to a further operation for completing the assembling of the same suitable for use in connection with the punch and die of the sheet metal perforating apparatus. For such completion of the stripper unit a swaging or expanding wedge or tool is employed which has a large round upper part 49 of a diameter corresponding to the bore of the upper part of the guide sleeve, a lower round part 59 of a diameter equal to the bore of the rib or bead 44 and the reduced lower part 5| of the opening in the supporting block 41, and a central downwardly tapering conical part 52 arranged between the large upper part 49 and the'small lower part 50 of the swaging tool. This tool is passed with its reduced part lowermost through the stack of loosely assembled stripper elements until its lower small end engages the small part 5| of the guide opening in' the supporting block and the large upper part of the tool engages with the bore of the guide sleeve and the small lower end of the conical part 52 of the tool reaches the bore of the temporary bead 44 in the guide sleeve. Upon now moving the swaging or expanding tool downwardly another step by means of the ram 53 of a press, or otherwise, while the supporting block 46 rests on the bed or table 41 of a press, the tapering part of this tool, by engaging with the internal bead or rib 44 of the guide sleeve, will move the latter downwardly until the shoulder 43 of the sleeve engages the upper side of the lower collar 4|, as shown in Fig. 6, and place the spring 42 under an initial compression. Thereafter a continued downward movement of the swaging tool independently of the sleeve and the other elements of the stripper mechanism will cause the taperthe upper collar 38 also depresses the latter and ing part 52 of the toolto displace or swage the; head 44 outwardly so that the same disappears guide sleeve which enters the enlarged lower part,

of the bore of the lower collar and engages with the downwardly facing shoulder 45, as shown in Pig. 7, thereby locking the lower collar 4| between the lower shoulder 43 and the external head 54 of the guide sleeve and connecting the same, so that the same are firmly united and incapable of being separated by ordinary means.

In order to produce the best effect from the punch it is necessary to guide the same fully to the extreme outer end or cutting edge of its bit and the present invention therefore provides means for accomplishing this result which are so constructed that a change of punch from one size to another can be made and still utilize nearly all of the same stripping mechanism with various sizes of punches. In the construction shown in Figs. 1 and 2 for accomplishing this purpose, a guide button is employed which has a guide disk 55 bearing with its upper side against the lower end of the guide sleeve 31 and its lower collar and adapted to rest with its underside on top of the sheet of metal or workpiece which is to be perforated. At its central part this guide disk is provided with a guide opening 56 which receives the bit or lower cutting end of the punch body and positively guides the same in its movement toward and from the workpiece. At its periphery this guide disk is provided with an upwardly projecting annular guide flange 51 which surrounds the periphery of the lower stripper collar 4| and slides with its peripheral surface on the bore of the guide opening I5 in the hom-of the punch holder. In this construction the lower stripper collar is spaced from the bore of the guide opening IS in the punch holder and the guide button 55, 51 therefore performs the whole function of guiding the lowermost end of the punch bit on the holder and maintaining the bit in accurate alinement with the cutting edge of the slug opening in the die.

When no workpiece is present between the punch guide button and the die the punching unit which merely floats inv the guide opening II of the holder drops by gravity so that the punch guide button rests on the die button. Upon now pushing a workpiece between the die and punch guide button, which can be done due to the chamfered, bevelled or cam edge 58 on the die and the chamfered, rounded or cam edge I. on the punch guide button, the latter together with the punch and stripper elements will be lifted by the wedge action of the chamfered edges 5!, 5! when engaged by the edge of the workpiece. During the subsequent descent of the ram 20 the same upon engaging the head and body of the punch will cause the lower cutting or bit end of the punch body to move downwardly in the punch guide button and into engagement with the workpiece and cut out a slug from the latter so as to form a hole therein, which slug is discharged through the central opening in the die and the delivery chute in the base of the holder. As the body and head of the punch descend, this head by engaging the top of compresses the stripper spring 42 a greater exa -and' h n oi the ram is moved from of the head and body of the punch, the resilience of the spring 42 lifts the h upper collar 3! and also the punch supported thereon and strips the bit of the latter from the hole which has been formed in the workpiece.

when it is desired to produce holes or perforations of a diiferent size in a workpiece it is only necessary to replace the punch and guide button by one of the appropriate size and assemble them with the same guide sleeve 31, upper and lower collars 38, 4| and spring 42, inasmuch as these stripping and guiding elements do not require changingor disassembling but can be used with any size of punch and punch guide button. r

By avoiding the necessity of replacing the entire punching unit when changing from one size of perforation in the workpiece to another'and instead only replacing the punch and the punch guide button to meet requirements and using the same stripper elements in connection with different sizes of punches the cost of the equipment for perforating holes of diilerent sizes is substantially reduced.

Instead of utilizing the punch guide button as the sole means of guiding the bit of the punch in the guide opening l5 of the punch and die holder, as shown in Fig. 1, this guiding effect may be divided between the lower collar of the stripper mechanism and the punch guide button, as shown in Fig, 8. As there shown the lower collar ll of the punch guide sleeve 31 has its upper part of sufllciently large diameter that the periphery SI of the same engages with the bore of the guide opening IS in the horn of the punch holder and the upwardly projecting annular flange 62 of the punch guide button also engages the bore of the guide opening I! of the holder horn but surrounds only the reduced lower part 63 of the lower stripper collar 80.

In both forms of this improvement shown in Figs. 1 and 8 only the punch and the punch guide button need to be replaced when changing from one size of perforation in the workpiece to another size and thereby eilecting an economy in doing work of this character.

I claim as my invention:

1. A punching unit for use in connection with a sheet material perforating apparatus having a holder, a die mounted on the lower part of the holder and a guide opening in the upper part of the holder, said punching unit being arranged in said opening and including a punch having a vertical body arranged in the center of said opening and terminating at its lower end in a bit and provided at its upper end with a head, a guide sleeve in which said body slides, a lower collar swaged on the lower end of said sleeve, an upper collar slidable on the upper part of said sleeve and limited in its upward movement thereon and engaged by said head. a spring interposed between said lower and upper collars, and a lower guide button which is separate from said lower collar and which has a central guide opening receiving said bit and slidingly engaging its periphery with the bore of said opening in the holder.

2. A punching unit for use in connection with a sheet material perforating apparatus having a holder, a die mounted on the lower part of the a holder and a guide opening in the upper part of the holder, said punching unit being arranged in said opening and including a punch having a vertical body arranged in the center of said opening and terminating at its lower end in a bit and provided at its upper end with a head, a guide sleeve in which said body slides, a lower collar secured to the lower end of said sleeve, an upper collar slidable on the upper part of said sleeve and limited in its upward movement thereon and engaged by said head, a spring interposed between of the holder, said punching unit being arranged in said opening and including a punch having a vertical body arranged in the center of said opening and terminating at its lower end in a bit and provided at its upper end with a head, a guide sleeve in which said body'slides, a lower collar secured to the lower end of said sleeve and spaced from the bore of the guide opening in the holder, an upper collar slidable on the upper part of said sleeve and limited in its upward movement thereon, a spring interposed between said collars, and a guide button engaging its upper side with the underside of said lower collar and having a central guide opening which receives said bit and provided with an annular guide flange which projects upwardly between the periphery of said lower collar and the bore of the guide opening in the holder and slidingly engaging the latter.

4. A punching unit for use in connection with a sheet material perforating apparatus including a punch having a cylindrical body terminating at one end in a bit, and a head which is separate from the body and which is swaged on the opposite end ofsaid body.

5. A punching unit for use in connection with a sheet material perforating apparatus including a punch having a cylindrical body terminating at one end in a bit and provided at its opposite end with a plurality of annular grooves,and a head provided with an opening which receives the grooved end of said body and secured thereto by displacing material of said head inwardly from the bore of its opening into said grooves and thereby interlocking said body and head.

6. A punching unit for use in connection with a sheet material perforating apparatus including a punch body, a guide sleeve in which said body slides, an upper collar slidable on the upper part of said sleeve, a lower collar connected with the lower part of said sleeve, and a spring interposed between said collars, said lower collar being provided in its bore with adownwardly facing shoulder and said sleeve having a downwardly facing shoulder engaging the upper side of said lower collar and having its lower part arranged within said lower collar and expanded into engagement with the downwardly facing shoulder of the lower collar.

GEORGE F. WALES.

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