US2500327A - Bench tool for forming end loops on helical springs - Google Patents

Description

March 14, 1950 2,500,327

J. L. SMITH BENCH TOOL FOR FORMING END LOOPS 0N HELICAL SPRINGS Filed Dec. 11, 1947 2 Sheets-Sheet 1 INVENTOR- cJ&0/ 51722222 J. L. SMITH 2,500,327 BENCH TOOL FOR FORMING END LOOPS on HELICAL SPRINGS March 14, 1950 2 Sheets-Sheet 2 Filed Dec. 11, 1947 JNVENTOR.

SJZZZ Jas ga Patented Mar. I4, 1950 UNITED STATES ssr OFFICE BENCH TOOL FOR FORMING END LOOPS ON HELICAL SERINGS This invention relates to a bench tool for forming end loops on helical springs, and more par ticularly for putting a double bend loop on the end of a helical spring. Some of the features of this tool are common to applicants copending application, Serial No. 721,389, filed January 10, 1947, which covers a hand tool for putting a double bend loop on the end of a helical spring, and the present application is a continuation in part thereof.

Inasmuch as the copending application neither distinguishes nor compares single bend, sometimes called a hook, from a double bend loop and inasmuch as applicant will concurrently or short 1y file an application on a hand and bench, single bend, or hook forming tool, the two types of loops will here be made clear. Referring to Figure l of the accompanying drawings, the upper end of the spring 1B is shown'in perspective and the hook #2 lies in a plane substantially at right angles to the plane of the loop I l, by virtue of a bend at It and a twist (or long bend) at 38 result ing from a force moving along arrow 26. In Figure 3, the hook 22 is formed'by a single bend at 24 resulting from a force moving along arrow 26, see Figure 4, with a force holding at arrow 28. If only a hook centrally positioned on the end of a helical spring is wanted, the single bend loop may be superior because its single ninety degree bend 24 is less likely to Weaken it than are the approximately ninety degree bend it and the twist it likely to weaken a double bend loop such as 12.. Also, the amount of energy necessary to form the double bend loop is substantially greater than that required to form a single bend loop, and this becomes important when forming loops on springs made of the heavier weights of wire.

However, a tool that will form the hook 22 of Figure 3 by the application of forces described in the last paragraph lacks versatility in that it will not form a full closed loop which is desired for many applications. Thus, referring to Figure 3, a closed loop would be formed by the dotted .extension 30 whose end would be adjacent bend 24, but, referring to Figure 4, this result would not obtain. Instead, the end of the loop would be lying in position 32. In contrast. a tool which will form the double bend boo: of Figure 1, can form a closed loop, as indicated by the dotted line 3.4,.01 a multiple loop, .as shown in Figures .15., 6 and. 9 of copending application :Serial No. 721,339. By exercising care, the end 23 of, a hook such as 22., see Figure 3, may be brought so close to the point H as to form .a substantially closed -semi=oircular hook, which is a good substitute for a fully closed loop.

The general object of this invention is to pros vide a bench tool having a single punch and a single di capable of light production assignments 1" or double bend hooks or loops on a comparatively wide range of spring diameters and spring wire weights. Many factories require springs in such quantities as to justify a kick press and sets of dies, one for each diameter spring. A workman requiring fifty springs must set up the tools on the punch plate and die holder. A feature of applicants tool is its single punch, single anvil and single anvil stop whose relative position may be varied to handle different springs.

The first object of this invention is to provide a ram movable along a straight line toward a sloping flat surfaced anvil having a cleaver edge. Fundamentally, this is an application of the punch it moving arcurately toward an anvil, more particularly toward a surface which forms an acute angle with the movement of the ramsee Figures 3 or 6 of co-pending application, Serial No. 721,339.

The second object of this invention is to associate with said anvil, an anvil stop whose spring engaging surface is at a right angle to the line of movement of the ram.

The third object of this invention is to elimihate move .ent of the helical spring during the loop forming operation. As explained in the second paragraph on page 11 of the co-pending application, where the punch is fixed, the helix must move laterally. This is all right in a hand tool where one hand holds the plier-like looping tool and the other hand holds the spring. This is not desirable in a tool which is intended to handle heavy gauge wire. The present tool carries a side stop for limiting movement of the helical spring laterally, and the swivel punch turns on a, center which is not the center of the punch itself, with the result that the punch itself fol.- lows around during the bending operation while the helix remains still.

A feature of this swivel punch is a spring adapted to return it to normal position after loop forming operation.

These and such other objects as may hereinafter appear are attained in the embodiment of the invention hereinafter described and shown in the accompanying drawings wherein:

Fig. 1 is .a perspective view of a double bond hook on a helical spring;

Fig. 2 is a side elevation of the hook shown in Fig.

Fig. 3 is a perspective view of a single bend hook on a helical spring;

Fig. 4 is a side elevation of the hook shown in Fig. 3;

Fig. 5 is a side elevation, partially in section, of applicants bench tool;

Fig. 6 is a front elevation thereof; and,

Fig. '7 is a perspective view of applicants loop bending swivel punch.

Fig. 8 is a vertical view of the punch.

Continuing to refer to the drawings, the numeral 40 identifies a casting having at its lower end a conventional clamp 42 with tightening screw 44 and having on its upper end an anvil holder 46 separated by a bight 48 from a ramsupporting head 50. Mounted on the head 50 by a bolt 68 is a casting 52 which carries a vertical cylindrical opening 54, in which rides a cylindrical punch holder 56. The upper end of the punch holder is pivotally mounted on a lever 58 whose outer end so is pivotally joined to a link 62 whose other end is pivotally mounted on a bracket 64, which is part of a casting 52. The punch holder 56 is tapped at its lower end axially by a cylindrical opening 58 in which is seated the shank TB of a punch 12. This punch is shown in perspective in Figs '7, where it is seen that the work end of the punch carries the slot 14 as described in the copending application, Serial No. 721,339.

Recessed in the inner side wall of the punch 12, referring also to Figs. 7 and 8, is a screw seat H6 connected to the top surface of the punch 12 by a slot H8. The adjacent bottom side wall of the ram 56 is milled inwardly to form a recess l2il which has an upwardly directed slot 122. A pin or spring 124 made of spring metal and having a hook end I is held by a screw 128 so that the end of the spring I24 is in the slot I22. When the punch l2 swivels in either direction during formation of right or left hand hooks, the spring I24 returns the punch to normal position when pressure between the spring loop and the punch groove 14 is released.

The anvil bears number 84 and is rigidly fixed to the anvil holder 46 by a pair of countersunk screws 86 and 88. The numeral 98 identifies the cleaving edge and 92 the cleaving surface which lies in the same plane as a similar surface 94 on the casting. An anvil stop 96 has a fiat spring engaging surface 98 which is at right angles to movement of the punch 12. The stop 96 is mounted on the anvil by set screw 100 which is in a slot I02 in the anvil stop. A side stop (04 has a transverse slot 106 in which is mounted a set screw [68, seatable in a hole in the anvil 8d.

The tool is used in the following manner.- A workman wishes to place a hook or loop on the end of a helical spring. He first sets the anvil stop 95 to a point where the surface 98 is below the cleaver edge 98 by slightly more than half the diameter of the spring by means of a screw I00. He then sets the side stop I04 so that its spring engaging edge I it is distant from the vertical axis of the ram 56 or the punch 12 by approximately one half the diameter of the spring.

He then places the end loop over the cleaver edge 90, positioning the end of the spring so as to form either a hook or a loop as desired, and positions the slot 14 over the wire of the second loop. The operator then depresses the handle 59 and in so doing the end loop is bent as illustrated in the dotted line position H l of Figure 5. Referring to Fig. 6, it will be noted that the punch has turned on the vertical axis of the punch holder as indicated by the dotted line H2, which means that the helical spring H4 has remained in its vertical axial position, because of the side stop 1M, and the punch has followed around as the end loop has been bent because the wire resists slipping longitudinally in the slot 14. The advantage of this tool is that without employing punches and dies specifically designed for a given size helical spring having a given weight of wire, a workman can turn out a large number of springs having identical loops or hooks on the end of them and can do it quickly. Unlike the hand tool where care in holding the helix while the end loop is being formed is important, in this tool, the side stop, plus a light control by the workmans left hand, holds the helix remarkably steady.

As illustrated the power is provided by the lever 58. In the case of light production tools, it is anticipated that the entire casting 42 may be mounted on or incorporated into a kick press and electric, hydraulic, or other power may be utilized to move the ram.

Having thus described my invention, what I claim is:

l. A tool for forming a loop or hook on the end of a helical spring comprising a frame, spaced jaws on the frame, a loop cleaving edge mounted on one jaw, a ram mounted on the other jaw and movable along a substantially straight line toward the cleaving edge, a swivel mounted on the work end of the ram and rotatable at right angles to the line of movement of the ram, and a punch mounted on the swivel off the center of the axis of the ram.

2. The tool of claim 1 wherein the punch has a downwardly directed groove substantially parallel to the cleaving edge when the punch is in its normal, raised position.

3. The tool of claim 2 together with means for returning the swivel to its normal position whenever the punch is out of engagement with a spring wire.

4. A tool for forming a loop or hook on the end of a helical spring comprising a frame, a pair of jaws mounted on said frame in spaced relation ship, a ram disposed in one jaw and movable along a substantially straight line toward the other jaw, a punch mounted on the ram for engaging the side of a loop of spring wire and pushing the side of the loop toward the axis of the spring, an anvil mounted on the other jaw, a spring loop cleaving edge mounted on the anvil at one side of the line of travel of the punch, and an anvil stop mounted on the anvil in the line of travel of the punch, said stop being adjustable in postion toward or away from the cleaving edge.

5. The tool of claim 4 together with a side stop mounted on the anvil adjacent the line of travel of the punch and adjustably movable substantially parallel to the cleaving edge.

6. The tool of claim 4 wherein the surface of the anvil stop engageable by the punch lies in a plane normal to the movement of the punch.

'7. A loop forming tool for helical springs comprising a frame, two spaced jaws mounted on said fame, a ram mounted on one jaw and movable along a substantially straight line toward the other jaw, a punch mounted on said ram, an anvil mounted on the second jaw, a loop cleaving edge formed on the upper side of the anvil and at one side of the path of the punch, a flat surface on the anvil extending from the loop cleaving edge obliquely downwardly so as to intercept the line of movement of the punch at an obtuse angle, an anvil stop having a flat surface movably engageable with the fiat surface of the anvil, a slot through the anvil stop, a set screw through the slot and seated in the anvil, and a plane surface on the anvil stop normal to the line of movement of the ram and normal at least in one line to the axis of the slot.

8. The tool of claim 7 together with a side stop having a surface movably engageable with the flat surface of the anvil along a line normal to the movement of the ram, a slot through the side stop parallel to its line of movement, and a set screw through the slot and seated in the anvil.

9. A bench tool for forming loops on the end of helical springs comprising a frame, an upper jaw and a lower jaw spaced from each other to provide a lateral opening mounted on said frame, a clamp for holding a frame to a Work bench mounted on the frame beneath the spaced jaws, a vertically movable ram mounted in the upper jaw, a cylindrical hole tapped in the lower end of the ram, a swivel having a stem rotatably seated in the hole, a wire engaging groove mounted on the lower end of the swivel of? center from the stem of the swivel, a substantially straight loop cleaving edge mounted on the lower jaw inwardly of the line of movement of the punch groove, a flat surface formed on the anvil and extending from the cleaving edge downwardly and out wardly so as to intercept the path of the punch groove, said cleaving edge and fiat surface forming part of an anvil mounted on the lower jaw, a guideway in the flat surface normal to the cleaving edge, a spring support consisting of a slide having ways complemental to the guideways of the anvil surface and in engagement with said surface, a spring supporting surface on that side of the slide adjacent the cleaving edge, a slot through the slide parallel to its ways, and a set screw through the slot and seated in the anvil.

10. The bench tool of claim 9 together with a spring having one end mounted on the swivel of the punch and the other end held by the ram for returning the swivel to a selected vertical relationship to the ram.

JOSEPH LEIGH SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 689,520 Sanker Dec. 24, 1901 906,418 Harter Dec. 8, 1908 1,311,187 Sleeper July 29, 1919 1,793,210 Craigo Feb. 17, 1931 2,123,752 Soderstrom July 12, 1938 2,268,824 Hicks Jan. 6, 1942

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