US2405778A

US2405778A - Die structure for bending sheet metal

Info

Publication number: US2405778A
Application number: US513331A
Authority: US
Inventors: Crawford Francis
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-12-08
Filing date: 1943-12-08
Publication date: 1946-08-13
Anticipated expiration: 1963-08-13

Description

D R O F w A R C E DIE STRUCTURE FOR BENDING- SHEET METAL Dec 2 sheetswsh t l IIIIIIIII Y L V I Ewan? ra ra Patented Aug. 13, 1946 UNETED STATES PATENT OFFICE DIE STRUCTURE FOR BENDING SHEET METAL Francis Crawford, Scarsdale, N. Y. Application December 8, 1943, Serial No. 513,331

10 Claims.

while avoiding undesirable lateral shifting of the sheet metal regardless of face contour thereof during the bending operations.

A more specific object is the provision of a simple and effective male die structure which includes a plurality of prick-punches extending a relatively short distance from the working surface to be engaged into the stock of the sheet metal accurately to hold it in position as a bend is died therein, and'its combination with cooperating female die structure.

Another object of the invention is to provide such die structure whereby in the formation of bent sheet metal articles necessity for preliminarily cutting stock oversize, then bending and finally trimming to dimension resulting-in loss of material is efficiently eliminated.

Still another object of the invention is the provision of such male die structure wherein a plurality of sockets are provided removably to receive alternatively prick-punches and properly shaped plugs to permit employment at will of as few or as many work-locating prick-punches and any specific arrangement thereof as may be dic tated by a particular job while assuring smooth substantially continuing working surfaces at sockets where the employment of prick-punches is not desired.

An additional object of the invention is the provision of structural embodiments of the apparatus which are readily constructed and allow eflicient use and operation thereof.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

different known types of embossed floor plate stock which may be accurately bent with the employment of die structure of the present invention;

Figs. 2 and 4 are sectional elevations of the embossed floor plate stocks shown respectively in Figs. 1 and 3, with Fig. 2 taken on line 22 of Fig. 1 and Fig. 4 taken on line 4-4 of Fig. 3;

Fig. 5 is an elevational sectional View of male and female die structure of the present invention 7 showing in section a piece of embossed floor plate Fig. 1 and 3 are top plan fragmentary views of 55 held therebetween in a predetermined position for the accurate formation of a bend in the plate; Fig. 6 is a side elevational view of the structure shown in Fig. 5, with parts of the dies broken away and showing the piece of floor plate sectioned along the line on which it is to be bent;

Fig. '7 is an end elevational view of die structure similar to that shown in Figs. 5 and 6, showing in section a piece of embossed floor plate to be bent located between the dies in reversed position; and I Fig. 8 is a side elevational view, with parts broken away, of the die structure shown in Fig. 7,

showing the floor plate sectioned along the line, such as line M of Fig. 3, on which it is to be bent.

Prior to the present invention it has been deemed by those skilled in the art of handling and bending embossed floor plate stock to be impractical or impossible to cut the stock to accurate dimensions and then to form a desired bend in the accurately dimensioned pieces along a predetermined line. the fact that in many designs of embossed floor plates the patterns of the bosses thereof cause differing cross-sectional areas or thicknesses along different vertical planes. This is true of the two well known types of embossed floor plates shown in Figs. 1 to 4, inclusive, wherein in Figs. 1 and 2 the Diamonette and in Figs. 3 and 4 the Waffle" patterns are respectively indicated. It will readily be seen from an inspection of these figures that the Diamonette plate It and the Waffle plate 1 l are Weaker along planes between adjacent rows of their respective bosses I 2.-|2 and. i3-I3. .Thus in attempting to bend such stock between male and female dies there is a tendency for plates thereof to shift laterally to a line of least resistance, or for sloping faces of the bosses when brought into contact with'anangularly disposed face of the male die structure to cause a lateral shifting away from the line along This is at least partially due to able that it has given rise to a common practice in the art of first forming a desired bend in an oversized piece of the embossed stock and then trimming the resulting bent piece to dimension. This, of course, causes undesirable wastage of material and further increased costs due to additional trimming operations required. These and other difiiculties of the prior art are efiiciently eliminated by the present invention.

In the drawings like numerals identify similar parts throughout. In accordance with one em bodiment of the invention disclosed in Figs. 5 and 6, the die structure preferablycompiises a female die l5 having an elongated groove 36 formed in its face which groove by way of example, for the formation of a substantially sharp bend such as at a right angle, is V-shaped as shown. A male die I! i provided to cooperate with the female die l5 and it has a complementary elongated ridge 18 to cooperate with the groove l6 for the formation of a bend along dot-dash line H), for example, inapiece of embossed floor plate 18.

In order to avoid lateral shifting of the piece of embossed floor plate stock, or other sheet metal stock, when the female and male dies i5 and H are caused to approach each other, a plurality of prick-punches 2il2il projecting a relatively short distance from the surfaceof the ridge [8 are employed. This is preferably accomplished by providing a plurality of cylindrical socket 2 2i along the edge of the ridge l8 removably to receive therein cylindrical, pointed prick-punches, preferably formed from specially treated hardened steel. It is particularly desirable that the prick-punches 29-49 be of such longitudinal dimension asto project from or beyond the surfaces of the ridge 18 only a limited distance so that they will not pierce entirely-through the sheet metal stock or embossed floor plate. The prick-punches are employed merely to pierce into the surface of thesheet metal stock or steel floor plate sufficiently to anchor the plate in position to prevent the' latter from slipping or shifting laterally during bending operations.

The number of prick-punches 21B-20which' are employed may vary'in accordance with the dietates of a particular job or the result desired. Accordingly, prick pun'chesare removably mountedinthe sockets 2 1-2 i with'rathera tightfit to assure their remaining in proper position during operation of the die structure. Removal of the prick-punches 20'-28' is provided for by a plurality of knock-out holes' -22'-22 each of which extendsthrough the body of the male diel'l' from the base portion 23 thereof to. one of the Sockets 2!: so that a driving'rod may be received therein. The'number'of prick-punches'is determinable by the allowable-tolerances in bending a particular sh'eetmetal stock. The more punche employed the more accurate will be bends formed by the die structure. It hasbeen found to be desirable to provide a wide male die with a plurality of sockets located at'intervals of about three inches. This will assure the provision of as many prickpunchesas will probably be found to be desirable for any particular job demanding the employment of a maximum-number thereof.

However, the fewer the number of prickpunches which. can be employedwhile still assuringsuflicient accuracy ofbend for a particular job; thatis, with-aparticular type of sheet metal stock; the moresatisfactory may be the results sinceithere will'be' less tendency for weakening of thestock along bend: lines, less surfacemarring, etc. Therefore, it is desired that as few iii punches as it is conveniently possible to use on a particular job be employed but that, when prick-punches are omitted from certain sockets, those blank sockets do not present sharp edges or deforming surfaces which might tend to mar the work and that there be no void space in the die stock along working surfaces. Accordingly a plurality of plugs, such as shown at 24 in Fig. 6, are provided, each of which is removablyreceivable in one of the sockets and when so seated has its exposed end contoured similarly to the contour of the face of the male die to provide a substantially unbroken working surface. These plugs 24-44 are preferably formed of material similar to that employed in the construction of the male die H, such as steel.

It is frequently desirable to reverse the em.- bossed fioor plate when it is positioned between the dies, that is, with the substantially flat bottom face thereof positioned adjacent the male die, as shown in Figs. '7 and 8. In those figures a typical embodiment of the invention, which has been constructed and is now in commercial use, has been shown approximately to scale. It is in dicated therein that the prick-punches 29-20 extend from the edge of the bending ridge I8 less than the thickness of the base of the plate stock. For example, for one-eighth inch embossed steel floor plate stock the prick-punches preferably extend about three thirty-seconds of an inch, so that should any prick-punch chance to be located between bosses where the stock is thinnest, such as at 25, the prick-punch will not pierce through. An advantage of this positioning of the floor plate stock between the dies is that when the prick-punches 20- 20 first engage the floor plate a the dies are caused to approach each other there are noboss sloping surfaces to be engaged by the tapered points of the prick-punches which might in some cases tend to cam the plate sideways for lateral shifting thereof. Of course the position of the floor plate stock between the dies frequently will be dictated by the direction in which the bend or bends is or are to be made for a particular job. Where the edge of a stair tread is to be turned down to overlie the riser the plate will bebent in accordance withthe teaching of Figs. 7 and 8, but should it be desired to bend the other edge of the plate upwardly to overlie the succeeding riser then the other procedure proposed in Figs. 5'and 6 will be employed to perform suchbend.

The present invention has in actual commer cial operations proven to be of great importance in the art of bending embossed floor plate stock and unexpectedly to accomplish desired ends which previously had been thought by those skilled in the art of bending and handling embossed floor plate stock'to be'impossible of attainment. The invention eliminates the necessity of precutting pieces of stock to oversize dimensions, then bending them and finally trimming to actual dimensions with reference to a bend or bends formed as an intermediate step or steps.

It will thus be seen. that the objects set forth above among others are 'efii'ciently attained and since certain changes may be made in the above construction and different embodiments of the invention could be mad without departing from the scope thereof, it is intended'that all matter' contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of: the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: 1. Dies for bending sheet metal of a certain minimum over-all thickness, and the like, comprising, in combination, a female die having an elongated V-shaped groove in its face, a male die comprising a substantially solid relatively unyielding body having a complementary elongated V- shaped ridge to cooperate with the groove, and a plurality of localized prick-punches projecting a relatively short distance from and beyond all portions of the edge of said V-shaped ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position as the dies are brought together to assure accurate location of a bend, those portions of the surface of said ridge intervening said prosockets projecting a relatively short distance from the surface of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position as the dies are brought together to assure accurate location of a bend.

3. Dies for bending sheet metal of a certain minimum over-all thickness, and the like, comprising, in combination, a female die having an elongated groove in its face, a male die having a complementary elongated ridge to cooperate with the groove, said male die having a plurality of sockets in the face of said ridge arranged along the portion thereof which is farthest from the base of said ridge, a plurality of prick-punches removably seated in at least some of the sockets projecting a relatively short distance from the surface of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position as the dies are brought together to assure accurate location of a bend, and at least one plug remcvably seated in one of the sockets having its exposed end contoured similarly to the contour of the face of said ridge to provide a substantially unbroken Working surface.

4. Dies for bending sheet metal of a certain minimum over-all thickness, and the like, comprising, in combination, a female die having an elongated V-shaped groove in its face, a male die having a complementary elongated V-shaped ridge to cooperate with the groove, said male die having a plurality of sockets in the edge of said V-shaped ridge. a plurality of prick-punches removably seated in at least some of the sockets projecting a relatively short distanc from the edge of said V-shaped ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position as the dies are brought together to assure accurate location of a bend, and at least one plug removably seated in one of the sockets having its exposed end contoured similarly to the contour of the edge of said ridge to, provide a substantially unbroken Working surface. 7

5. A male die for cooperation with a female die to bend sheet metal of a certain minimum overall thickness, and the like, comprising an elongated ridge providing a Working face and having a plurality of sockets therein arranged along the portion thereof which is farthest from the base of said ridge, and a plurality of prickpunches removably seated in at least some of the sockets projecting a relatively short distance from the working surface of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position during theformation ofa bend therein.

6. A male die for cooperation with a female die to bend sheet metal of a certain minimum over-all thickness, and the like, comprising an elongated V-shaped ridge providing a working face and having a plurality of sockets therein arranged along the portion thereof which is farthest from the base of said ridge, and a plurality of prick-punches removably seated in at least some of the sockets projecting a relatively short distance from the V-shaped edge of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal with: out perforating it to hold it securely in predetermined position during the formation of a bend therein.

7. A male die for cooperation with a female die to bend sheet metal of a certain minimum over-all thickness, and the like, substantially along a straight line comprising a relatively wide die body having a mounting base portion, an elongated ridge extending along said body opposite said base portion and providing a working face, said ridge. having a plurality of sockets therein extending toward said base portion and said body having a plurality of knock-out holes each extending therethrough from said base portion to one of the sockets, and a plurality of prick-punches removably seated in at least some of the sockets projecting a relatively short distance from the working surface of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position during the formation of a bend therein.

8. A male die for cooperation with a female die to bend sheet metal of a certain minimum over-all thickness, and the like, substantially along a straight line comprising a relatively wide die body having a mounting base portion, an elongated V-shaped ridge extending along said body opposite said base portion and providing a working face. said ridge having a plurality of sockets therein extending from its edge toward said base portion and said body having a plurality of knock-out holes each extending therethrough from saidlbase portion to one of the sockets, and a pluralityrof prick-punches removably seated in at least some of the sockets projecting a relatively short distance from'the edge of said V-shaped ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierce into a surface of the sheet metal without perforating it to hold it securely in predetermined position during the formation of a bend therein.

9. A male die for cooperation with a female die to bend sheet metal of a certain minimum over-all thickness, and the like, substantially along a straight line comprising a relatively wide die body having a mounting base portion,'an elongatedridge extending along said-body opposite said base portion and providing a working face, said. ridge having a plurality of sockets therein extending toward said base portion and said body having a plurality of knock-out holes each extending therethrough from said base portion to one of the sockets, a plurality of prick-punches removably seated in at least some of the sockets projecting a relatively short distanc from the Working surface-of said ridge and substantially less than the mentioned minimum thickness of the sheet metal to be bent to pierc'e'into a surfaceof the sheet metal without perforating it to hold-it securely in predetermined position during the formation of a bend therein, andatleasti one plug removably seated in each of the sockets having its exposed end contoured similarly to the contour of the face of said ridge to provide a substantially unbroken working surface.

10. Dies for bending sheet material of acertain minimum over-all thickness, and the like, comprising, in combination, a female die-having an elongated groove in its face, a male die comrising a substantially solid relatively unyielding body having a complementary elongated ridge to cooperate with the groove, and a plurality of localized prick-punches arranged along the poltion of the ridge which is farthest from the base thereof and projecting from and beyond all portionsof the surface of said ridge toward the deepest portion of the groove in said female die a relatively short distance substantially less than the mentioned minimum thickness of the sheet ma terial to be bent; those portions of the surface of said ridge intervening said projecting prickpunches being substantially uninterrupted and backed by solid male die body material, said prick-punches thus being adapted to pierce'into a surface of the sheet material without perforating the latter to hold it securely in predetermined position as the dies are brought together and thus assure accurate location of a bend.

FRANCIS CRAWFORD, V