US2146788A - Wire-drawing die and method - Google Patents

Description

Feb. 14, 1939. H. BLOUNT 2,146,788

WIRE DRAWING DIE AND METHOD Filed May 20, 1936 FIG! Fl 6. a FIG. 4

T3 3534 25 2a .24 as a a7 \gJ DVI a if INI/ENTOR y H. BLOUNT 51R MM A TTORNEY Patented Feb. 14, 1939 UNITED STATES PATENT OFFICE ern Electric Company,

Incorporated, New

York, N. Y., a corporation of New York Application May 20, 1936, Serial No. 80,706

12 Qlaim s.

This invention relates to a wire drawing die and method and more particularly to a method of and die for drawing wire having an oval or flattened cross section.

In the manufacture of metallic strands for various purposes where special irregular cross sections are required having one transverse dimension considerably greater than another at right angles thereto, and where such strands are made from circularly cylindrical wire, it is found in some instances to be desirable to convert the circularly cylindrical wire into elliptically or ovally cylindrical wire as a preliminary step before rolling or drawing into the final irregular form. An illustrative example of such procedure may be found in the manufacture of copper wire or tape having a Z-shaped cros section such as is used in the manufacture of certain types of electricalcoaxial conductor cable.

Objects of the present invention are to provide a method of and a simple and durable die, by means of which the method may be practiced. for drawing circularly cylindrical wire into a strand having a flattened, elliptical or oval cross section, such that the members of the die having the drawing surfaces thereon may be readily dismounted for repair and easily and accurately reassembled.

In one embodiment, the invention contemplates a structure comprising a holder in which two complementary blocks are held in juxtaposition by a single locking member, each block hearing at one end against an individual stop and at the other end against a common selfadjusting stop, the blocks being formed with complementary arcuate drawing faces. By means of this structure the method may be practiced for making substantially oval or non-circular wire or ribbon.

Other objects and features of the invention will appear from the following detailed description of one embodiment thereof taken in connection with the accompanying drawing in which the same reference numerals are applied to identical parts in the several figures and in which Fig. 1 is a view in end elevation of a die constructed in accordance with the invention;

Fig. 2 is a view in section on the line 2--2 of Fi 1;

Fig. 3 is an enlarged detached view in end elevation of one of the two complementaryblocks;

Fig.4 is a view in section on the line ii-t of Fig. 3;

Fig. 5-is an end view of the self adjusting looking wedge pin; 7

Fig. 6 isa side view thereof, and

Fig. 7 is an enlarged cross sectional diagram to show the relation between the stock being drawn and the die.

In the illustrative embodiment of the inven tion herein shown there is presented a die constructed in accordance with the invention and adapted to be used in any suitably arranged familiar type of wire drawing machine. The foundation of the die is a generally circularly cylindrical body member 20 with plane, parallel transverse ends and having a partly tapered, partly parallel walled aperture 99 longitudinally oriented from end to end. A rectangularly cross sectional slot 2i extends transversely through the body and is here shown as somewhat below the central level although it may be central or above center to correspond to the requirements of whatever machine is to receive it for use therein.

A pair of complementary rectangularly parallelopipedal blocks 22 and 23 are housed in the slot 2| and have a snug sliding .fit therein. Each block 22 and 23 has an insert, 24 and 25 respectively, set therein of hard and wear resisting ma-. terial.

A radial, tapped bore 26 extends down from the top of the block to and partly beyond the top of the slot 2! and houses a complementarily thread- .ed locking screw 21, whose lower end abuts against the top surface ofthe block 22 to lock the two blocks in place.

At its right end (Fig. 1) each block 22 and 23 abuts against a. plane face formed on an otherwise circularly cylindrical stop pin, 28 and 29 re.- spectively, mounted in corresponding bores in the body and parallel to the axis of the body. The left face of each block 22 and 28 abuts against a plane face 3| formed on a common locking pin 30. This pin 30 is a circular cylinder having a portion cut away by a plane making an acute angle wit the axis of the pin so that the pin tapers. Furthermore it has a V groove 32 along the center line of the face 3i. The pin 30 is mounted in a corresponding bore 33 passing through the body 20 at an angle to the vertical central plane thereof equal to the angle of taper of the pin 30.

All the parts described except the inserts 24 and are preferably made of suitably selected steel, heat treated as may seem desirable. The inserts 2E and 25 are preferably made of tungsten carbide or other suitable hard and wear resisting material. I

Over the centralparts of their mated surfaces the blocks 22 and 23 and the inserts 20 and 25 are formed identically symmetrical drawing surfaces asbest shown in Figs. 3 and 4, the arcuately concave contours shown in Fig. 3 being arcs of circles and the convex contour shown in Fig. 4

a sequence of four straight line segments. so that The method and means for forming and restoring the drawing surfaces of the inserts 24' out from back to front (right to left in Fig. 2)

by means of a suitable drift, after the screw 21 has been backed out a trifle to release its pressure on the block 22. The pin 30 having been removed, the blocks 22 and 23 may be driven from right to left (Fig. 1) out of the slot 2| for exchange, examination, regrinding or any other purpose. I

To assemble thedie, the blocks 22 and 23 are inserted into the slot 21 face to face and pushed or driven in until they stop against the pins 28 and 29 respectively. The pin 30 is then inserted into its bore and driven home, wedging the blocks firmly and longitudinally immovably into place against the stop pins 28 and 29. Should one of the blocks be a trifle longer than the other, the pin 30 can rotate accordingly in its housing and the groove 32 will provide clearance for the overhanging block comer. Finally the screw 21 is tightened down holding the blocks vertically immovably in the body. A characteristic feature of the die thus made is the shape of the drawin aperture between the concavely arcuate opposed facets of the inserts 24 and 25. Any transverse section of this aperture is formed of two circular arcs enclosing between them an area tapering arcuately to two points. Such a figure is known in geometry and in the architectural arts as a vesica piscis and as used in this specification and in the appended claims the words vesica and vesicate are intended to mean this figure and having the form of this figure.

In operation the die is used in the same. way a any other die block, the wire. or rod to be drawn being pulled through the laterally elongate and vertically compressed aperture of the die from front to back (left to right in Fig. 2). It is ordinarily not possible to use for wire drawing a die whose drawing surface is presented by more than one piece or member, for under the heavy stresses of the wire drawing operation, the joints of a non-integral die will yield and the comers of the component members will open at the joint and will cause either scorings or fins or both to appear on the product. In the present instance however, when a circularly cylindrical wire or rod 39 is drawn through a die having a vesicate aperture of suitably chosen dimensions, the drawing stock does not fill the corners of the vesica but is formed inthe die to have a flattened cross section with rounded ends as shown in Fig. 7. Hence the stock does not come into contact with the joints of the die and so is neither scored nor finned by the joints.

When such a vesicate die in two parts-is too worn for further use, it may be recut without enlargement oi the aperture for renewed use on the same size of stock (an impossibility with a one piece die) as disclosed in the companion application mentioned above.

The embodiment of the invention herein disclosed is,illustrative only and may be modified and departed from in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. A die for drawing wire to substantially elliptically cylindrical form, comprising complementary die members having opposed concavely arcuate drawing facets forming together a vesicate drawing aperture.

ing die having a vesicate drawing aperture, and means to hold the die members together in the 4. A die for drawing wire and comprising fixed die elements presenting a non-circular drawing aperture of greater cross-sectional area-than that of the wire to be produced thereby.

5. A die for drawing wire and comprising fixed die elements presenting a non-circular drawing aperture having a cross section of greater area than the cross section of the wire to be produced thereby, the cross section of the aperture being convexly angular in form.

6. A die for drawing wire and comprising means presenting a non-circular. drawing aperture having a cross section of greater area than the cross section 'of the wire to be produced thereby, the cross section of the aperture being vesicate in form.

7. A die for drawing wire and comprising complementary fixed die members presenting a noncircular drawing aperture of greater cross-sectional area than that of the wire to be produced thereby.

8. A die for drawing wire and comprising complementary fixedjiie members presenting a noncircular drawing" aperture having a cross section of greater area than the cross section of the wire to be produced thereby, the cross section of the aperture being convexly angular inform.

9. A die for drawing wire and comprising complementary means presenting -'a non-circular drawing aperture having a cross section of reater area than the cross section of the wire to be produced thereby, the cross section of the aperture being vesicate in form.

10. A method of drawing wire which comprises the step of advancing a wire through a drawing die in which the, drawing aperture of the die is non-circular and of greater cross-sectional area than the wire issuing therefrom, theaperture being vesicate in cross-sectional form.

11. A method of making a substantially oval wire which comprises drawing a wire of circular a circular wire through fixed die elements to form the wire into a. shape having an oval cross-section and then rolling the wire of oval cross-section between rolls to form a ribbon.

HARRY Broom.

transverse aperture and matched to form a draw-

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