US2108253A

US2108253A - Die shoe

Info

Publication number: US2108253A
Application number: US28695A
Authority: US
Inventors: John C Dense
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-06-27
Filing date: 1935-06-27
Publication date: 1938-02-15
Anticipated expiration: 1955-02-15

Description

Feb. 15, 1938. I J. c. DENSE 1 2,108,253

DIE SHOE Filed June 27, 1955 3 Sheets-Sheet l Feb. 15, 1938. J. c. DENSE 2,108,253

DIQYE SHOE Filed June 27, 1935 3 Sheets-Sheet 2 INVENTOR.

Feb. 15, 1938. J. c. DENSE 2,108,253

DIE SHOE Y I Filed June 27, 1955 3 Sheets-Sheet 3 IN VENTOR.

ATTORNEYS Patented Feb. 15, 1938 UNITED STATES DIE SHOE

John O. Dense, Rochester, N. Y.

Application June 27,

7 Claims.

This invention relates to a die shoe, or support, for what is commonly known as blanking and piercing dies used in connection with a movable punch to remove blanks of various forms and shapes from a web of-material, or to pierce the web. The die is generally provided with an aperture, or recess, of shape complemental to the blank desired, and the punch is formed with an external configuration complemental to the aper- 10 ture or passage in the die. These punches and dies are used in What is known as punch presses which are heavily constructed machines provided with a suitable support for the die, or the die shoe, and a reciprocating mechanism, or ram, for moving the punch toward and from the die.

An object of this invention is What might be termed a master die shoe for supporting the die on the bed, or frame, of the punch press, the 20 construction being such as to readily permit substitution of a large number of dies on this master die shoe.

It is general practice to support a die on what is commonly called a die bolster, or die shoe, which is usually a piece of thick, heavy, cast iron provided with means for attachment to the bed of the press, and having its upper face machined off and the die mounted thereon. An opening is formed through the die bolster, or shoe, to permit passage of the blanks as the punch removes them from the web. At the present time, what is known as die sets can be purchased on the open market. A die set consisting of a bolster or shoe, and a punch carrier. The die shoe is usually provided with one or more guide posts, and the punch carrier provided with openings to slidably receive the guide posts. The die shoe and punch carrier come in a semi-machined condition, and the die maker proceeds to make 40 the die and punch, and attach the die to the die shoe, and the punch to the punch carrier.

The die shoe, die, punch carrier, punch and stripper plate, if used, in practically all instances constitute a tool or item. That is, the die and the punch are permanently attached to the die shoe and punch carrier respectively, and are not removed therefrom until it becomes necessary to repair, or replace, either the punch or the die.

The great disadvantage in this method of 1935, Serial No. 28,695

cial standpoint, rises rapidly. In addition, there are practical disadvantages, such as handling a large mass of heavy iron and making provision for storing the same. In some plants, the inventory of these die sets runs into a tremendously high figure, particularly in plants where a large number of blanks are used, for example in typewriter and adding machine plants.

Some attempt has been made to overcome these existing disadvantages by providing some means for adequately supporting the dies, and which would permit interchangeability of the dies with the support, or die shoe. For example, the ordinary die shoe has been provided with four studs and the die block and stripper plate slidably mounted upon these studs, supported by two parallels underneath, resting on springs. This construction has not been satisfactory, due to the fact that the die and stripper plate have a tendency, on account of small area of contact with the studs, to bind during operation with the result that the die is often cracked or broken.

Another method of trying to meet the demand for a cheap type of die has been to use the ordinary die shoe and locate the die block upon its upper surface by means of dowels or a dovetail strip on either side of the die block, and to cut a hole through the die shoe to permit the blank to pass through. This necessitates having this hole through the die shoe large enough to take the maximum size of blank, and when the minimum size of blanking die is used, the die block is unsupported due to the large hole through the die shoe and the thin die block will probably be. broken.

Other systems have been worked out for temporarily tooling, but which are not practical for production work. For example, in one system a loose punch is manually placed in piercing or blanking position, is forced through the stock by power, manually reclaimed after passing through the die, and manually placed in position for the next operation. This system sometimes effects a saving where only a few blanks are desired but, of course, is of no benefit whatever in volume production.

The general object of my invention is to over come all these difiiculties, and to provide a die support to which, as stated above, the dies can be readily and conveniently attached and removed.

It is also an object of the invention to provide for all dies that may be attached to the support, an absolutely rigid and fixed support.

This feature is of importance in that it permits the dies to be made from a piece of tool steel a fraction in thickness compared to what is usually used. The importance of this feature will be obvious to those skilled in the art. It not only saves die material, which consists of very expensive steel, but reduces the time consumed by the die maker to a fraction of that usually consumed in making the similar die under present methods.

A further object of the invention is to provide a die set including the die shoe economical in cost, and at the same time permitting any number of different dies and punches, within limits of size, to be used in the die set, thereby obviating the necessity of storing the die set, that is the die shoe and punch carrier, in the stock room when a particular tool is not in use, and unnecessarily building up the inventory of the plant.

Other objects and features will appear as .the description proceeds.

The invention consists in the .novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1 is a front elevation, partly in section, illustrating the construction of the die set.

Figure 2 is a view, similar to Figure 1, of the die support illustrating the relative position of the parts when the punch has just pierced the blank from the stock.

Figure 3 is a top plan view of the die support with a die shown thereon.

Figure 4 is a top plan view of the punch carrier.

Figure 5 is a front elevation similar to Figure 1.

Figure 6 is a plan view of the die carrier.

The die shoe comprises generally a base, a die carrier slidably mounted in the base, a die rail or support rigidly mounted in the die shoe and arranged to support the die during the piercing or blanking operation of the punch.

|El designates the base, which is similar in form and shape to the die shoes now in common use. The base is provided on each end with bifurcated lugs H for attaching the shoe to the bed of the punch press. The base H] is also provided with guide posts l2 which are usually pressed into apertures formed in the die shoe and extend upwardly at right angles to the top, or face, of the shoe. The purpose of these guide posts i2 is to suitably guide the punch carrier I5 which comprises a thick, flat portion of the general shape shown in Figure 4, and a pair of bosses I6 properly bored to slidably receive the guide posts 52. The punch carrier I5 is also generally provided with a cylindrical boss i'l extending upwardly from its top surface, and which is suitably attached to the ram, or reciprocating member, of the punch press.

20 designates the punch which, as here shown, is a plain cylindrical punch for blanking out disks. The punch 20 is affixed to the die carrier I5 in any suitable manner depending somewhat upon the construction and type of punch. As here shown, the punch carrier I5 is provided on its under surface with what might be termed a punch pad 2| which consists of a flat piece of steel secured to the punch carrier at its corners by countersunk screws 22. The punch carrier 15 is also provided with a pair of dowel pins 23, these pins being :a press fit in the punch carrier I5, and projecting outwardly a short distance from the under face of the carrier and extending through apertures formed in the punch pad 2|. The punch may be formed with, or attached to, a punch holder 24 which is provided with apertures complemental to the dowel pins 23. Preferably, one of the dowel pins 23* is larger than the other pin. This is done to assure the punch holder 24 being attached to the die carrier .5 always in the same relative relationship. The punch holder 24 is detachably secured to the carrier I5 by cap screws 25.

designates die which, as here shown, is provided with a circular aperture complemental to the form of the punch 20. A stripper plate 3| may be employed, and is held in spaced apart relationship from the upper surface of the die 30 by spacers 32.. The spacers 32 are slightly thicker than the web or stock fed through the die, and extend inwardly from the outer edges of the die 30 and stripper plate 3|, and act as guides for the sides of the stock, or web, being passed through, or over the die.

The construction of the die shoe will now be described. This shoe consists of the base It, or equivalent member. The base is formed with a circular hole or passage 33 which, as here shown, is counterbored, or increased in diameter on the under side of the base, as at 34 and 35. A hardened bushing 36 is pressed into the aperture 33, the bushing being provided with an annular shoulder 31 which seats in the counterbore 34. The bushing or sleeve 36 is formed with a bore 38 extending an appreciable portion of its length, and with a counterbored portion 39 adjacent the bottom of the sleeve.

40 designates generally the die carrier. The die carrier 40 is formed cylindrical and provided with a head or flange 4|. The die carrier 40 is slidably mounted in the bushing 36 with the greater portion 42 of its outer surface in contact with the circular opening 38, and the periphery of the head 4| in sliding contact with the counterbore 39.

The die carrier is also formed with a comparatively wide and deep slot 43 which extends diametrically across the carrier and opens in the face or upper side of the carrier. The purpose of this slot will be explained hereinafter.

The die carrier 4|] is inserted in the bushing 36 from the under side, and is normally maintained in elevated position with the flange or shoulder 4| in contact with the top of the counterbore 39 in bushing 36, as indicated in Figure l, by helical compression springs 44, the upper ends of which are mounted in recesses 45 formed in the under side of the die carrier, and the other ends of the springs in similar recesses 46 formed in the upper face of the circular cover plate 41.

It is to be observed that the comparatively large cylindrical surface of the die carrier 46, operating with a close sliding fit in the bushing or sleeve 36, provides an excellent sliding support for the die, and any clamping, or binding, is entirely eliminated. Obviously, the die carrier 40 may be slidably mounted in direct contact with the aperture formed in the base 10. However, I prefer to employ a hardened sleeve or bushing, such as 36, as the life of the die shoe is materially extended, and accuracy is maintained during the life of the shoe. The die carrier 40 and the bushing 36 are preferably hardened, ground and lapped so as to have a perfect relative sliding fit.

aio'aess The die'sho'e Iii, in addition to being provided with the boreto receive the bushing 35 and closure plate 41, is also provided with a slot 50 extending across the face of the die shoe and com- 5 *plemental in width with the slot 43' formed in the upper face of the die carrier 40. This slot 50 is not as deep as the slot 43 inthe die carrier 40. As shown in Figure 3, the 'slot 5|) extends across the face of the die shoe l from front to o back. However, the slot 50 may be arranged lengthwise of the die shoe, if desired. In either event, the slot 55 extends diametrically across the aperture or passage 33. Y

A' die rail-or die support is mounted in the l5-slot 50, and-secured in place at its ends as by screws 52. The support 5| consists of'a piece of tough, strong, steel preferably hardened. The support 55 is of such width as to provide a close sliding contact with the side portions of the die barrier. That is, the die support 5! extends through the slot 43 and the die carrier 40. The construction and relative arrangement of the die carrier 40 and die support 5| constitutes an important feature of my invention. The die support 5| is a solid, integral piece of steel, and acts as the support for the die during the piercing, or blanking, operation. The die rail or support 5| is of sufficient thickness to withstand the stress exerted on the die during operation of the punch. The slot 55, in which the support 5! is mounted, is of such depth as to provide suitable thickness in the base H3 below the bottom of the slot, and in instances where the base It must be of appreciable thickness below the slot 50, and the die support 5| must be of appreciable thickness, the support 5| may extend, or pro ject, above the upper surface or face of the base I0. 'When these parts are dimensioned, the die carrier 40 and slot 43 are dimensioned accord- ,m ing'ly. The upper surface of the die support 5! extends parallel with the upper surface of the base Ill.

The side portions 55 of the die carrier 40 are slidable between the sides of the die support 5| .:and the bore 58 of bushing 35. The depth of the slot 43 'is such that when the top faces of the side portions 55 are flush with the top of the die rail 5|, there is a slight clearance between the bottom of the die carrier and the cover plate AM, as indicated at 55, Figure 2. As here shown, the flange or shoulder 4| of the die carrier is formed relative to the bottom surface 57 of the slot 43, so that the flange 4| coacts with the top of the counterbore 39, leaving a slight clearrance between thebottom of the slot 45 and the bottom. of the die support 5|, as indicated in Figure 1.

As here-shown, the sides 55 of the die carrier are provided with dowel pins 55, 59, similar to mbthe dowel. pins 23, 23 The dowel pin 58 being slightly larger in diameter than the dowel pin 59 to insure the attachment of the die to the'die carrier always in the same relative position. The die 30 is locatedrelative to the die carrier 4%] :by'the dowel pins 58, 59, and the die and stripper plate 3|, if used, are detachably secured to the die carrier as by cap screws 56.

It will be observed, that the die 35 is detachably secured to the side portions 55 of the die "carrier 40, with the die extending across the slot 43 and support 5|, and with the aperture of the die arranged centrally over the die sup port. The bottom of the die carrier may be provided with an aperture 48 to release air from 7 the space below'the "rail 5|.

The die 38 consists of a relatively thin, flat piece of steel, here shown as circular in form, 1

44. It will be observed that the slot 43' and die carrier 40 is appreciably deeper than the thickness of the'die rail 5|, so that there is an appreciable space between the bottom of the die 30' and the'upper surface of the die rail 5|, when the die carrier is in normal elevated position,

as in Figures 1 and 5. As the punch 20 descends and contacts the web, or stock, the die 3|! and diecarrier 40 are pressed downwardly against the action of the springs 44 until the bottom of the die rests upon and is supported by the support 5!. Further downward movement of the punch 20 effects the removal of the blank from the web, forcing the blank into the aperture of the die, or if the aperture is formed with sufficient clearance; the blank will drop upon the faced the rail 5|. As the punch ascends, the die carrier 40, die 30, stripper plate 3|, are elevated partially by the pulling of the punch through the web, and partially by action of the springs 44 until the flange 4| of the die carrier coacts with the top of the counterbore 39, or to the position shown in Figures 1 and 5.

It will be observed that the die 30, during the cutting or piercing operation, is supported by di rect contact with the solid die support or rail 5|. That is, the support 5| contacts the complete under surface of the die about the aperture in the die. Or, in other words, there is no overhang whatever to the die.

In practice, it is preferable to provide theun der surface of the die with a slight marginal recess 6! about the bottom of the aperture of the die, this recess being exaggerated in Figures 1 and 2 of the drawings. In practice, the

recess 6| is only a matter of a few thousandths I of an'inch larger than the aperture in the'die.

The purpose of the counterbore or recess 6| 'is to receive the bottom-most blank of the stack that may collect in the aperture die, because of slight,

or no clearance in the die aperture.

The upper surface of the die rail 5| is preferably provided with a plurality of lengthwise ex-- tending grooves 62. These grooves extend to a slight depth and are used to minimize the friction of the blank as it passes over the face of The web, or

the die rail after leaving the die. stock, is usually coated with grease, or oil, to

prevent rusting before use, and occasionally the oily blanks have a tendency to adhere to a flat- I have found that formingmagnetic steel to avoid the thin blanks sticking to the die support. under the die 39, over the face of the die rail 5| The blanks slide from in by gravity on an inclined press, or by the application of compressed air, or other suitable means, on a horizontal press.

It will be observed, that there is an appreciable space between the bottom of the die 3!! and the face of the die rail 5|,

when the die carrier is in elevated position. This permits the blanks to be conveniently removed from beneath the die.

Referring to Figure 2, it will be observed that; during the piercingpr blanking operation by the punch, the die is adequately and rigidly supported by the die rail 5|. It will also be observed that the die 30 and stripper plate 3| may be quickly and conveniently removed from the die carrier 40, and a different die attached thereto,

and each die will be fully supported about the margin of the die aperture. Or, in other words, any one of a number of dies may be attached to the die carrier, and regardless of the size of the apertures in the dies, the die will be adequately supported. I have found that if the die support described is made in three sizes, all ordinary piercing or blanking dies used are provided for, each size accommodating any shape or form of die within the limits of the support.

Due to the fact that the die 30 is rigidly supported about the margin of the aperture in the die, the die may be formed of comparatively thin metal. There is no' overhang, that is, the sup port 5| coacts with the under surface of the die right to the edge of the aperture. The advantage of being able to form dies. of comparatively thin material will be appreciated by those skilled in the art, as it materially reduces the time employed in making the aperture in the die.

When the required number of blanks have been obtained, the die 30 and stripper plate 3! may be quickly and conveniently removed from the die support by simply removing the four cap screws 60, and another die and stripper plate instantly attached to the die carrier. In like manner, by removing the four cap screws 25, the punch 20 and holder 24 may be removed from the carrier l5 and another punch complemental to the new die quickly attached to the holder.

It will be observed while my die shoe possesses many apparent advantages, it is not a temporary tool, but a permanent tool suitable for volume production.

What I claim is:

1. The combination of a die and die shoe, of a punch element movable toward and from the die shoe, said die shoe comprising a base formed with an aperture opening through the upper face thereof, a die carrier slidably mounted in said aperture and being formed with a slot extending across its upper face, a fixed die support mounted on the base and extending transversely tosaid aperture and through said slot in the die carrier, means for detachably securing a die to the upper face of the die carrier with the die arranged in spaced apart relationship from the upper face of said support, said die carrier being cooperable with the punch element, upon movement of the same toward the die shoe, to press the die downwardly into engagement with said die support.

2. The combination of a die and die shoe, of a punch element movable toward and from the die shoe, said die shoe comprising a base provided with an aperture extending therethrough, a carrier for the die slidably fitting the aperture in the base and being provided with a slot extending across the upper surface thereof, said die being detachably secured to the upper surface of the side portions of said carrier and extending across said slot, a support mounted on the base and extending transversely of the same and through said slot beneath the die, said slot being formed of greater depth than the thickness of said support, thereby permitting the die carrier to slide vertically in said base and move the die toward and from said support upon vertical movement of the punch element, and resilient means normally maintaining the die carrier in outward position with the die spaced from the die support.

3. The combination of a die and die shoe, of a punch element movable toward and fromv the die shoe, said die shoe comprising a base provided with an aperture extending therethrough, and a slot extending'transversely of the upper surface of the base and across said aperture, a carrier for the die slidably mounted in said aperture and being provided with a slot across its upper surface coextensive in width with the slot in the base, but of greater depth, said die being detachably secured to the upper surface of the die carrier on either side of the slot and extending across the slot, 2. die support consisting of a rail mounted at its ends in the slot formed in the base and extending through the slot formed in the die carrier, whereby the die carrier is movable vertically upon vertical movement of the punch element to carry the die toward and from said support, and means urging said die carrier outwardly to normally maintain the die in spaced relation to said support.

4. The combination of a die and die shoe, of a punch element movable toward and from the die shoe, said die shoe comprising a base provided with a central aperture extending therethrough, a bushing mounted in said aperture, a die support extending transversely of the base across said aperture, 21. die carrier mounted in said bushing and having vertical sliding movement relative to said support, the die being detachably secured to the upper surface of said carrier and extending over the upper surface of said support, a cover plate for said aperture secured to the under side of the base, a compression spring interposed between said cover and the bottom of the die carrier to normally maintain the die carrier in up position with the die spaced apart from the upper surface of the die support, the die carrier and said bushing having means cooperating to limit the upward movement of the die carrier.

5. The combination of. a die and a die shoe, of a punch element movable toward and from the die shoe, said die shoe comprising a base formed with an aperture opening through the upper face thereof, a rigid die support carried by the base, a die carrier member, means for detachably securing the die thereto, said die carrier being adapted to maintain said die in operative relationship to the punch at all times and being slidably mounted in said aperture in the base to permit engagement of the die with the support when under pressure executed upon the die by the punch during the shearing operation, and resilient means co-operable with said die carrier to normally maintain the die in spaced apart relationship to said support.

6. The combination of a die and die shoe, of a punch movable toward and from. the die shoe, said die shoe comprising a base provided with a rigid die support for supporting the die during the shearing operation, a die carrier slidably mounted in the base and means for detachably securing the die to said carrier, and said carrier being adapted to normally maintain said die in spaced relation to the support and being operable to carry the die into and out of engagement with said support, and said carrier being cooperable with said support to prevent relative movement between the die and said shoe in the horizontal plane.

'7. The combination of a die and die shoe, of a punch movable toward and from the die shoe to efiect a shearing operation, said die shoe comprising a base, a rigid die support carried by the base, a carrier for the die slidably mounted in the base at each side of said support, means for detachably securing the die to said carrier, and said carrier being adapted to maintain said die in operative relationship with the punch at all times with the opening of the die arranged over the upper face of said support, resilient means cooperable with said carrier to normally maintain the die in spaced apart relation above said support, and said carrier being operable during sliding movement to permit engagement of the die with the support under pressure executed upon the die by the punch during the shearing operation.

JOHN C. DENSE.