US3827272A

US3827272A - Sheet steel draw die

Info

Publication number: US3827272A
Application number: US00353596A
Authority: US
Inventors: L Maiale
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-04-23
Filing date: 1973-04-23
Publication date: 1974-08-06
Anticipated expiration: 1991-08-06

Abstract

A draw die assembly for extruding sheet steel material and the like comprising a pair of opposed dovetail shaped dies supported within complementally formed slots located in a pair of die holder members. A plurality of wear plates are interposed between the inner periphery of the slot and the engaging surfaces of the dies whereby to facilitate removal of the dies for sharpening or regrinding. In one form of the invention, three pairs of dies are provided with each pair being adapted to successively reduce the thickness of the material. In a second form of the invention, the thickness of the material is reduced by integral multi-drawing blades disposed in each of a single pair of opposed die elements.

Description

United States Patent [1 1 Maiale 1 Aug. 6, 1974 SHEET STEEL DRAW DllE Primary ExaminerMilton S. Mehr [76] Inventor: Louis J. Maiale, 3831 w. Paint St., Attorney Agent FimHam@SS Dickey & Pierce Dearborn, Mich. 48204 [22] Filed: Apr. 23, 1973 ABSTRACT [2]] Appl. No.: 353,596 A draw die assembly for extruding sheet steel material and the like comprising a pair of opposed dovetail shaped dies supported within complementally formed [52] Cl 2 5 3 5? slots located in a pair of die holder members. A plural- 51] Int Cl T 37/02 ity of wear plates are interposed between the inner pe- [58] d 366 riphery of the slot and the engaging surfaces of the g g l 90 f dies whereby to facilitate removal of the dies for 81 1 sharpening or regrinding. In one form of the invention, three pairs of dies are provided with each pair being [56] R f Ct d adapted to successively reduce the thickness of the e erences l e material. In a second form of the invention, the thick- UNITED STATES PATENTS ness of the material is reduced by integral multi 1,103,927 7/1914 Audibert 81/180 B drawing blades disposed in each of a single pair of op- 2,l78,674 ll/l939 Simons 72/205 posed die elements,

R22,737 4/1946 Bailey 72/90 8 Claims, 5 Drawing Figures 4 m Z a" i 17 5 (I I V L t- 4 ii 55 if 57 J it '1' j i 7Z4] 4 )1 [Z4 j g L L TL A 24 /2 12 f4 a ,5 24 4 e SHEET STEEL DRAW DIE BACKGROUND AND SUMMARY OF THE INVENTION The present disclosure relates generally to the processing of ferrous metals, and more particularly to a new and improved method and apparatus for drawing sheet steel.

Generally speaking, sheet steel is mass produced for commercial and industrial applications by a process which typically includes both hot working and cold working the material. With respect to the former, rolling usually is the first step in converting ingots into finished parts. The rolling process consists of passing hot metal between rollers which revolve in opposite directions, and which the spacing therebetween is less than the thickness of the material entering, whereby the material is both squeezed and elongated and usually altered in cross section. This results in plastic deformation and accompanying grain refinement of the material when the rolling is accomplished at suitable tem peratures. Thereafter to further improve the surface finish and to obtain greater dimensional accuracy, the material is generally subjected to a cold working process, such as by way of example, cold rolling.

One disadvantage, however, of cold working the material resides in the need for special preparation of the hot worked material. In this regard, the scale of the material should be removed to avoid abrasion and pitting of the cold working apparatus. Scale removal is accomplished by a pickling process in which the metal is submerged in acid and thereafter washed. Frequently, the material is also subjected to a light cold rolling operation and in some instances the material can be annealed.

In the present invention, the material is extruded or drawn after the egress from a hot rolling mill at a high temperature level. Thus, the need for pickling the material is in most instances obviated, and the advantages for subsequently cold working are greatly diminished. It, therefore, is a general object of the subject invention to provide a process for extruding or drawing a sheet steel material which will provide an alternative to pickling and cold working and thereby reduce the manufacturing cost.

The present invention is comprised of one or more opposed and selectively spaced pairs of dies for drawing or extruding the material as it is drivingly forced therebetween. Due to the abrasive and pitting action of the material as it is extruded by the dies, it is desirable that the dies be easily removed to facilitate sharpening or regrinding. In the present invention, the dies have a triangular shaped cross section with an apex defining the drawing blade surface. The side opposite the apex is adapted to be located in a dovetailed slot. A plurality of wear plates are interposed between adjacent seating surfaces of each of the dies and slots, and the dies and slots are each tapered in a lateral direction relative to the longitudinal movement of the material whereby the die is easily freed in response to slight lateral movement, Conversely, when the die is being installed, it is easily located due to the initially relatively large clearance therebetween. It is, therefore, another object of the-subject invention to provide a combination die and holder therefor wherein the dies are easily installed or removed.

In one form of the invention, a plurality of longitudinally spaced and opposed sets of dies are supported in a holder in such a manner that the thickness of the material is successively reduced. All. of the dies and cooperating slots are dimensionally uniform but wear plates of varying dimensions are provided to successively decrease the openings between adjacent pairs of dies. The result is universality of application with respect to the dies and uniform machining for the slots. It, therefore, is another object of the subject invention to provide an apparatus for drawing sheet metal utilizing a uniform die construction which is locatable in a uniformly machined holder member.

In a second form of the invention a single pair of opposed multi-bladed or toothed dies are identically supported as in the first form, but disposed on an inclined surface of a wear plate. By providing a set of wear plates having an upper surface with varying degrees of inclination and by having one of the holders opposingly movable relative to the other, it is possible to adjust the bite or opening between the die blades. It, therefore, is a further object of the present invention to provide a system of wear plates which are adapted to selectively adjust the opening between opposed dies.

Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an exemplary draw die assembly in accordance with a preferred first form of the present invention, and a fragmentary representation of a hot rolling mill;

FIG. 2 is a cross-sectional view of the assembly illustrated in FIG. 1 taken long the lines 22 thereof;

FIG. 3 is a fragmentary side view of an exemplary draw die assembly in accordance with a preferred second form of the present invention;

FIG. 4 is a cross-sectional view of the assembly illustrated in FIG. 3 taken along the lines 4-4 thereof; and

FIG. 5 is an enlarged view of the closed within the circle 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For convenience of description, the terms upper, lower," right, left" and words of similar import will have reference to the various members and components of the draw die assembly of the present invention as arranged and illustrated in FIGS. 1-5 of the drawings and described hereinafter in detail. Likewise, the terms inner," outer and derivatives thereof, will have reference to the geometric center of such members and the various portions or sections thereof.

With reference now to FIG. 1 of the drawings, an exemplary first preferred embodiment of the subject draw die assembly is indicated generally at 10 and disposed down stream or to the right of a hot rolling mill 12. Generally speaking, the mill I2 is comprised of a series of rolling stands wherein ingots are first rolled into blooms and subsequently rolled in tages to form billets or slabs. The mill 12 can be assumed to be of any conventional construction or arrangement and forms no part of the subject invention. By way of example, however, and for purpose of explanation, the final stage of portion of FIG. 3 enthe mill 12 isshown as being comprised of a pair of rollers 14 and 16 which are adapted to revolve in opposite directions. The spacing between the rollers 14 and 16 is less than the thickness of the material entering whereby the material is squeezed and elongated and correspondingly changed in ross sectional shape. At the same time, due to the applied force of the rollers 14 and 16, the material also undergoes a plastic deformation accompanied by grain refinement which results in a more uniform and standardized product. For purposes of illustration, an exemplary section of work stock 18 is shown at 20 as being deformably squeezed in accordance with the spacing between the rollers 14 and 16. Moreover and also for purposes of illustration, the assembly can be disposed on the right or down stream side of the hot rolling mill 12 whereby the workpiece can be directly driven therein, or alternatively a separate pulling or driving means can be provided for conveying the work stock 18 therethrough. As will hereinafter be described, the assembly 10 is adapted to draw or extrude the work stock 18 whereby to obviate any further processing as is now conventional in the art.

In his regard, the assembly 10 is comprised of a plurality of triangularly shaped, laterally extending die elements 26, 28, 30, 32, 34 and 35 which are arranged in opposed sets and removably supported by upper and lower die holder members indicated generally at 22 and 24 respectively. The

members

22 and 24 are in turn connected to a suitable support structure (not shown) which includes means for adjustably locating the adjacent confronting surfaces thereof and accordingly, the opening or distance between the opposed die elements as shall hereinafter become apparent. In this regard both of the

members

22 and 24 can be movably supported or one can be immovably fixed with the other being movably. In the form illustrated in FIG. 1 of the invention, it will be assumed that the lower member 24 is fixed and the upper member 22 is suitably supported by the support structure for movement in a vertical direction relative to the member 24. The member 22 is provided with a plurality of longitudinally spaced, dovetail shaped grooves 38, 42 and 46 conforming in number to the dies, with each groove 38, 42 and 46 being adapted to support the die elements 28, 32 and 35 respectively. Correspondingly, the lower die holder member 24 is adapted to support the die elements 32, 34 and 35 in comparably formed, dovetail shaped grooves 36, 40 and 44 respectively. In accordance with a preferred form of the assembly 10, each of the die elements 26, 28, 30, 32, 34 and 35 are dimensionally identical and interchangeable whereby to provide standardization in the fabrication thereof. Moreover, the grooves 36, 38, 40,42, 44 and 46 are each dimensionally identical and of uniform shape and configuration. In the subject invention each of the elements 26, 28, 30, 32, 34 and 35 are removably supported in the grooves 36, 38, 40, 42, 44 and 46 respectively by a system of wear plates or pads which facilitates standardization of components and which further functions to precisely locate the opposed sets of die elements 26 and 28, 30 and 32, and 34 and 35 in preselected spaced relationship whereby the thickness of the work stock 18 can be successively decreased as it is longitudinally displaced across the assembly 10.

Because of the general uniformity and similarity of the die elements and identical cooperating grooves, the

system of wear plates will be described solelyfor the die element 26 and cooperating dovetail shaped groove 36, it being appreciated that the remaining elements and grooves are substantially identical subject to a dimensional variance which will hereinafter be described. The element 26 is comprised of a pair of

inclined side walls

48 and 50, a lower base surface 54, and an upper working surface 52 which is adapted to engageably extrude or draw the workpiece l8. Correspondingly, the groove 36 is formed by a lower base surface 64 and a pair of inclined

side wall surfaces

62 and 66. A lower wear plate 54 is interposed between the base surfaces 54 and 64 of the die element 26 and groove 36 respectively. In a similar manner a pair of side wear plates 56 and 58 are respectively interposed between the confronting side surfaces 48 and 62, and 50 and 66 of the die 26 and the groove 36. It will be noted that each of the wear plates 58, 60 and 56 are precisely machined to previously determined dimensions whereby to nestingly locate the element 26 relative to the groove 36 and locate the working surface 52 in fixed spaced relationship relative to the confronting upper surface of the holder 24.

To facilitate installation and removal of the die 26 in the groove 36 for purposes of sharpening or regrinding the working surface 52 of the element 26, the die 26 and groove 36 are each formed in a laterally extending, tapered relationship which is best seen in FIG. 2. With reference thereto, it will be seen that the oppositely spaced

edges

52a and 52b defining the work surface 52 are convergent in the direction indicated by arrow 51. In a like manner, each of the

side walls

48 and 50 and the base surface 54 have similarly convergent edges whereby the transverse cross section of the die element 26 also decreases in the direction of the arrow 51. In accordance therewith the slot 36 is formed of a complemtnary construction to cooperatively and slidably receive the die 26 in a manner whereby the die 26 can be initially inserted with the engaging surfaces thereof and the wear plates in spaced relationship, i.e. at least up to a certain point at which a tight friction fit will occur to lockingly engage the element 26 therein. It will be noted that the purpose of this feature significantly minimizes the effort to extract the die from the die holder and easily facilitates its reinsertion.

In the subject invention the wear plates are provided in sets for accommodation of opposed die elements such as by way of example, the elements 26 and 28. In this regard, it will be seen that the die element 28 is supported by an upper wear plate 59 and a pair of side wear

plates

57 and 55, the plates being identical to the wear plates 54, 56 and 58 respectively. In a like manner, the next set of die elements 30 and 32 are identically supported but since the opening between the working surfaces thereof is adapted to further extrude the workpiece 18, the thickness of each of a pair of identical wear plates 61 and 62 is increased relative to the thickness of the wear plates 59 and 60. In a like manner, a pair of wear plates 63 and 64 of still greater increased thickness relative to the wear plates 61 and 62 are utilized to support the next adjacent set of die elements 34 and 35. Accordingly, each of the side wear plates supporting the sets of die elements 30 and 32, and 34 and 35 are correspondingly formed of decreased thickness in the direction of travel of the work stock 18 to accommodate the increased extention of the upper and lower wear plates and the resulting opposed decreased opening therebetween. Although three sets of elements are illustrated in FIG. ll, it will be understood that additional sets of die elements may be provided in the assembly whereby the degree of extrusion of each set of elements can be increased or de creased for accommodation of a particular type of work stock 18.

For some applications, it may be desirable to utilize a single die element having multiple working or cutting surfaces in lieu of the plurality of die elements provided in the embodiment illustrated in FIG. 1. In this regard and with reference to FIGS. 3, 4 and 5, a second pre ferred form of the subject draw die assembly is indicated generally at 70. In a manner analogous to the construction previously described in conjunction with the first embodiment, the assembly 70 is comprised of upper and lower die holders 74 and 72 which are again suitably connected to a support structure which includes the provision of adjustably spacing one of the holders 74 or 72 vertically relative to the other. Each of the holder 74 and 72 includes laterally extending, dovetail shaped grooves or recesses 82 and 80 respectively which are adapted to support a pair of multiedged die elements 78 and 76. The die element 78 is supported in the groove 82 by an upper wear plate or pad 92 and a pair of side wear plates 90 and 94. In a like manner, the die element 76 is supported in the groove 80 by a lower wear plate 86 and a pair of side plates 84 and 88. As best seen in FIG. 4, the element 76 and groove 80 are each convergently tapered in a lateral direction corresponding to the arrow 51 in FIG. 2 whereby to provide the same advantages with respect to installation or removal to the die element 76. With respect to the opposed die element 78 and groove 82, the configuration and arrangement is identical and a mirror image of element 76 and groove 80 respectively.

With reference to FIG. 5, the element 76 includes three working or cutting edges 98, 100 and 102 which are formed on the upper surface thereof. To successively reduce the thickness of a section of work stock as it is driven across the die 76, the edges are inclined by virtue of being supported on an inclined uppe surface of the lower wear plate 86. By providing wear plates in matched sets differing from one another by the angle of inclination of the upper surface, it is possible to again provide selective control of the degrees or draw of extrusion attributable to each of the edges 98, 100 and 1102. Thus, the same degree of versatility can be incorporated in the second preferred form of the subject invention as was incorporated in the first form.

From the foregoing it will be seen that in the operation of the assembly 10 or 70, that a section of work stock is drawn or extruded in response to longitudinal displacement across the working surfaces thereof. As a result of the additional processing of the work stock, the normally additional conventional steps of pickling and subsequent cold rolling can be eliminated to provide a substantial savings in manufacturing costs. It will further be noted that a distinct advantage of the subject invention resides in the provision for an easy and expedient removal of the individual die elements to facilitate regrinding and sharpening and the subsequent reinstallation of the die elements in the assembly. Moreover, the provision of standard die elements loeatable in uniformly constructed recesses which is accomplished through the provision of the wear plates is adapted to provide still another advantage.

While it will be apparent that the preferred embodiments of the sheet steel draw die illustrated herein are well calculated to fulfill the objects above stated, it will be appreciated that the present invention is susceptible to modification, variation and change without departing from the scope of the invention.

What is claimed is:

1. A draw die assembly for extruding work stock comprising: an opposed pair of spaced die elements adapted for extruding the work stock; spaced apart holder means for said pair of die elements which are spaced a predetermined distance apart thereby; pad means interposed between said holder means and said die elements to preclude wear on said holder means; and means for feeding said work stock between said die elements for reducing the thickness thereof.

2. The assembly as recited in claim 1 wherein each of said die elements have a triangularly shaped cross section and wherein said holder means has a dovetailed recess for receiving one of said die elements.

3. The assembly as recited in claim 2 wherein said recess extends laterally relative to the movement of said work stock and wherein each of said recess and die elements are tapered in a lateral direction to facilitate removal and installation of said die elements.

4. The assembly as recited in claim 2 wherein said holder means comprises first and second holder members, and which includes means for moving one of said members relative to the other member to selectively adjust the spacing between said die elements.

5. The assembly as recited in claim 2 wherein said pad means includes a plurality of wear plates interposed between saId die elements and said holder means.

6. The assembly as recited in claim 5 wherein each of said die elements include more than one working surface and wherein said more than one working surfaces are inclined relative to the direction of travel of the work stock.

7. The assembly as recited in claim 6 wherein one of said wear plates includes an inclined surface for supporting one of said die elements.

8. The assembly as recited in claim 1 which includes a plurality of additional pairs of die elements, and wherein said additional pairs of die elements are also supported by said holder means for reducing the thickness of the stock seriatim as it passes from one pair of die elements to another.