US2341916A - Wire forming method and device - Google Patents

Description

Feb. 15, 1944. v H N 2,341,916

wrma FORMING METHOD AND DEVICE Filed Dec. 26, 1940 2 Sheets-Sheet 1 INVENTOR E1 KZ JZC.

ATTORNEY Feb. 15, 1944. v, HANSEN WIRE FORMING METHOD AND DEVICE Filed Dec. 26, 1940 2 Sheets-Sheet 2 IN VE OR Vwflw ATTORN EY Patented Feb. 15, 1944 WIRE FORMING METHOD AND DEVICE Veb Hansen, Brooklyn, N. Y., assignor of twothirds to John N. Ledbetter, Jr., New York,

Application December 26, 1940, Serial No. 371,736

4 Claims.

This invention relates generally to the subject of wire forming and more particularly to a method and apparatus for the continuous production of helically threaded, polygonally sectioned wires or similar objects.

Helically threaded wire is useful in many industries. One of its principal uses is in the production of threaded wire or screw nails.

I am aware of prior methods and machines for producing helically threaded wire. Some of these prior methods and machines operate upon a length of wire or similar blank, usually of angular cross-section, and. bodily twist the same into threaded form. Such 01d methods and machines are usually very complicated, costly, cumbersome and. set up torsional strains in the wire or blank operated upon. Other prior methods and machines which operate upon smooth surfaced wires or blanks, without bodily twisting the same, employ positively driven forming dies or rollers which are also complicated and expensive and lack. flexibility and. adaptability to varying conditions of wires or blanks.

My invention has for its object to obtain a new, better. and more economical result without repeating the objectionable. features of the old methods and devices.

Another object of my invention is the provision of a novel method and device for transforming wire or similar objects into helically threaded form in a simplified and economical manner and which method and device is adapted to be readily incorporated in existing equipment and requires a minimum of space in the factory.

Another object of my invention is-the provision of such a method and device which employs a minimum of moving parts, which does not set up torsional strains in the blank incident to the forming or transforming operation and which contemplates the use of floating forming means driven solely by their frictional contact with the moving wire or blank, whereby such method and device is made flexible and adaptable to varying conditions of wires or blanks, such as variations in hardness and dimension of the wire or blank.

Numerous other objects. and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

In the drawings:

Fig. 1 is a side elevation of a wire drawing apparatus embodying my invention,

Fig. 2 isa plan view of the apparatus,

Fig. 3 is an enlarged perspective view of a partly transformed piece of wire,

Fig. 4 is an elevational view, with parts in perspective, of the forming head taken at 4-4 in Fig. 1, but on a larger scale,

Fig, 5 is a side elevational view of the head, partially in section, taken along the line 55 in Fig. 4,

Fig. 6 is an enlarged transverse or cross section of a round wire, as an example, before entering the head, as indicated by the line 66 in Fig. 5.

Fig. 7 is an enlarged sectional view of the wire passing between the forming rollers, taken along the line ll in Fig. 5, and

Fig. 8 is an enlarged radial section of the remotest forming roller in Fig. 5 taken along the line 88.

The organized apparatus shown in Figs. 1 and 2, which includes the gist of my invention, comprises, generally, a frame I l on which are mounted a wire supply reel I2, a withdrawing or wire accumulating reel 13 and, intermediate these reels, a forming head M. These devices illustrate one form of apparatus whereby my method may be effected.

The reel l2 holds a supply of wire l5 which, for the purpose of exemplifying my invention, is round wire. The reel I2 is mounted for rotation on a horizontally disposed shaft l6 bearing at its extremities in grooves l! in the upper portions of a pair of standards it formed integrally with the frame II. The round wire is threaded through a guide 2|, secured to frame ll, then through forming head I4 and attached to the larger diameter lower portion of the frusto-conical withdrawing reel l3 adjacent a flange 22 formed at the lower end of the reel.

As viewed in Figs. 1 and 2, the withdrawing reel I3 is rotated clockwise by any suitable means such as the motor 23, which effects rotation of the reel through a worm 24, keyed to a motor shaft 25, and a worm wheel 26, keyed to the lower end of a vertical shaft 27, which is keyed at its upper end to the reel I3.

To prevent overrunning of the supply reel l2, a simple braking device is provided. This is shown as a brake block 39 fixedly secured to the upper and free end of a lever 3!. The lower end of the lever Si is pivotally mounted on a pin 32 set in a bearing 33 formd integrally with the frame H. A spring 34, hooked at one end to an eye 35 in the base of frame H and at its other end to the lever 3| through a hole 35. urges the brake block 30 toward the axis of the reel 12 and into frictional contact with the wire on the reel to effect the braking purpose above mentioned.

The round wire. I is drawn or forced through the head l4 in a continuous and steady manner by the withdrawing means heretofore described, the guide 2! serving to maintain substantial axial alignment of the advancing wire with the forming means of the head.

The forming head l4, as shown in larger scale in Figs. 4 and 5, comprises, in its preferred form, four forming rollers 4|, rotatably mounted on a base 42. Each of the rollers is provided with a ball-bearing 43 mounted upon a pin 44 fixedly secured in a lug or block 45 formed integrally with, and projecting transversely from the face of the circular base 42. Each of the pins 44 is so secured in a block 45 and the latter so disposed on the base 42, as to provide angular disposition of its associated roller 4|, relative to the axis of the base 42.

A tubular core 46 is threadedly secured to the centre of the base 42 and is journaled in a bearing 41 formed in the upper portion of the bracket 48 which is bolted to the frame ll. Ample clearance is provided between the core 46 and the bearing 41 and a thrust ball bearing 5| is secured in juxtaposed recesses 52, 53 formed respectively in the bearing 41 and the base 42.

This mounting of base 42 is adapted to take the thrust, incident to the operating pressure, upon the ball bearing, and also to centralize the base 42 with respect to the axis of its rotation so that the clearance between the tubular core 46 and the bore 49 is maintained, thereby providing a minimum of friction between the head and its supporting means during its operation.

A pair of lock nuts 54, 55 are secured to the left end of the core 46, as viewed in Fig. 5, for the purpose of retaining the core 48 within its bearing. A slight clearance is also provided between the inner lock nut 55 and the bearing 41 to prevent friction therebetween during the forming operation.

The angular mounting of the rollers 4| relative to the axis of the head and the axis of the wire is indicated by the letter A in Fig. 5. By virtue of this mounting the peripheries 56 of the rollers engage the wire, which passes between them, at an acute angle and as the peripheral formation of the rollers is slightly rounded as indicated in the enlarged section of Fig. 8 at 56, the resulting passage or die through which the wire is drawn or forced is a substantially square or polygonal funnel with freely movable concave walls, the round wire entering at the large end, and the polygonal wire emerging at the small end of the funnel. A transverse view of an end of this passage is shown in Fig. '7, looking toward the oncoming round wire l5, and shows a cross section of the substantially square or polygonal wire 58 thus formed. It should be notedthat the distance between diametrically opposite corners of this section remain about the same as the diameter of the round wire from which it is formed.

Due to the angular disposition of the rollers relative to the axis of the wire being formed, a component of the force, exerted in pulling the wire through the rollers or forming devices, is directed to the rotation of the head and its rollers around the wire, and imparts a helical thread formation to the transformed wire. Therefore, the head and its rollers, being freely mounted for rotation as heretofore described, may be referred to as a floating forming head driven by power imparted thereto through the wire itself. By this method the core of the wire is not disturbed by any torsional strains because the wire is not twisted, but is merely formed with helically advancing polygonal sections.

I have found that this method and means of drawing polygonally shaped wire provides a desirable compensatory feature when the wire being drawn varies throughout its length in diameter and/or hardness. My theory of this compensation or automatic adaptation is that, as the head is not positively driven by means outside of the wire, the varying diameter and hardness of the wire itself are factors in the driving of the head about the wire and it appears that the degree of force with which the head is rotated may be said to be a function of the pressure exerted by the rollers upon the wire. If the wire is slightly softer in one section than in another, the rollers will bear with less pressure upon the wire, the head will rotate slightly slower and a lesser force will be required to pull it through than would be required for the harder portions. This is desirable because the softer wire should be subjected to less tension than the relatively harder wire.

A similar advantage is apparent when wire of slightly varying diameter is drawn through the forming head. When wire of relatively smaller diameter is being drawn, a lesser pressure is applied by the rollers and tension in the wire incident to the feeding thereof is reduced.

The formed or transformed wire after being forced through the forming rollers is wound on the reel l3 starting at the flange 22 and subsequently working upward in a manner well known in the art.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts or in the steps of th process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form and process hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. The method of transforming round wire into helically threaded, polygonally sectioned wire by drawing said wire between forming rollers, said rollers being angularly mounted relative to the axis of said wire, each of said rollers being adapted to rotate about its own axis and the axis of the wire during the forming operation by power derived from the moving wire itself through its frictional engagement with said rollers during the forming operation, each of said rollers having a tapered and curved wire contacting surface, wire contacting surfaces of said rollers producing a plurality of helical curved sides and sharp corners in said wire.

2. The method of forming polygonally sectioned wire from Wire having a different section by forcing said wire through forming rollers angularly disposed with respect to the axis of said wire and rotatable about said axis by a component of the force applied to said wire, said com ponent of force being derived from said wire through the angular engagement of said rollers with said wire during the forming operation and rotating said rollers around said wire, each of said forming rollers having a tapered and curved wire contacting surface, thereby producing a plurality of helical curved sides and sharp corners in said wire without twisting said wire.

3. In a machine for forming wire into polygonal wire having a helical thread, comprising in combination, a frame, a base rotatably'mounted upon said frame, a plurality of rollers rotatably mounted upon said base with their peripheries at an angle to each other and forming a passage for said wire, means for feeding said wire through said passage, thereby forming said wire into the desired shape without twisting said wire, said base and said rollers being rotated by the frictional contact between said wire and the peripheries of said rollers, said passage being funnel shaped and defined by a plurality of concave sides connected by sharp corners.

4. In a machine for forming round wire into polygonal wire having a helical thread, comprising in combination, a frame, a base rotatably mounted upon said frame, a plurality of rollers rotatably mounted upon said base with their peripheries at an angle to each other and to the axis of said base, thereby forming a passage for said wire, means for feeding said wire through said passage, thereby forming said wire into the desired shape without twisting said wire, said base and said rollers being rotated by the frictional contact between said wire and the peripheries of said rollers, said passage being funnel shaped and being defined by a plurality of concave sides connected by sharp corners.

VEB HANSEN.

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