US1881981A - Method and apparatus for making prongs for loose-leaf binders - Google Patents

Description

Oct. 11, 1932. c. D. TRUSSELL 1,881,981

METHOD AND APPARATUS FOR MAKING PRONGS FOR LOOSE LEAF BINDERS Filed Nov. 11. 1930 INVENTOR W MEM By Attorneys @WLW w Patented Oct. 11, 193 2 UNITED STATES PATENT OFFICE CLARENCE D. TBUSSELL 0! 1 MANUFACTURING COMPANY, OF IOU 1 1 1 I 'NEW YORK mew 203K, nssrenon m raussm mzw zoax, a coaroan'rron or METHOD AND APPARATUS FOR IAIING PBONGS FOB IDOSE-LEAI' IBmDEBS Application filed ll'ovember 11, 1980. Serial No. 494,868.

.which are riveted or ot erwise fastened to plates which are mounted to have a rocking movement whereby to open or close the rings,a spring-plate or other resilient means being provided for holding the parts in either the closed or open position. Examples of such constructions are illustrated in my Patents Nos. 1,468,845, granted September 25, 1923, and 1,634,125, granted June 28, 1927. For convenience I will herein refer to the half-rings as prongs. In the closed position these prongs fit together and form a complete closed ring.

In the manufacture of such ring binders, it is desirable to practice the utmost economy consistent with the production of a suflicient- 1y strong product having proper exactitude in operation. The economic production of the prongs has presented a serious problem. They have heretofore been made, one at a time, by feeding forward the wire stock, cutting it ofi, and then bending to shape. This has been generally mainly a hand operation, although attempts have been made to perform it by automatic machinery.

According to the present invention, the wire stock is fed forward and cut ofi at a length adequate for making two prongs. The wire is then bent to approximately the shape of two prongs united by a middle ortion; then the middle portion uniting tnem is severed to separate the two prongs; and these are pinched between dies to give them a set in their final shape. Thus two prongs (which may be regarded as the two halves of one complete ring) are struck out at one operation, which not only doubles the product, but has certain other advantages which will be hereinafter stated.

The operation is performed by means of a pair of dies and their accessories, a suitable construction of which is shown in the accompanying drawings,wherein Figure 1 is an elevation of the dies, the lower die being partly in section in'a lane parallel with the line of feed of the stoc Fig. 2 is a fragmentary transverse section on the line 2-2 in Fig. 1';

Fig. 3 is a plan of the cutting-01f die which initially severe the stock;

Fig. 4 is a transverse section. of the bindmg elements of a suitable form of ring binder, including the prongs and their car-.

rier-plates and spring-plate, which illustrates the mode of mounting the prongs upon the carrier-plates by riveting;

Fig. -5 is a plan of the ring binder elements shown in Fig. .4;

Fi 6 shows the two prongs as first bent and fore cutting them apart;

Fig. 7 shows one of the prongs after severance, being the completed product of the.

present invention.

The method will be best understood after the apparatus has been described. Re errin to Fig. 1, A is an n per die and B a lower die, which are mounte in any suitable manner to be moved toward one another to operate on the stock and to be separated to release the stock. Normall the lower die B would be mounted on the ta 1e of a powerpress, and the upper die A. carried by the movable platen or slide of such ress. The lower die islprovided with a gui e a for the wire or stoc X from which the pron are to be formed. This stock is fed throug lo gitudinally in the path of the dotted lines 6 and is arrested blyl manual, althoug any usual automatic feed ma be provided if desired. The wire stock wil of course, be previously straightened in any well-known manner, and a guide (1 may be provided adjacent the stop a to hold the free advancing end of the wire strai ht while it is being acted upon by the dies. he lower die is formed with two arc-shaped recesses e, e between which is a'separatin portion 9,

which is preferably flat and leve as shown.

a stop 0. The feed may be The upper die is formed with two rounded projections 'f, f, between which is a portion h corresponding generally to the portion g of the lower die. A cutter C is provided for severing the wire after the required length has been fed into place. This is conveniently carried by the upper die, and as it descends it enters a corresponding recess C in the lower die, the two parts acting as a shear for cutting off the wire. The cutter may merely cut the wire, orit may cut out a short piece of scrap, as desired. This cutter gives any desired formation for the abutting ends of the prongs when assembled in place.

I11 operation the wire, after having been fed into place against the stop a, is, by the descent of the upper die, first severed by the cutter C and then acted upon by the rounded projections or bosses f, f and carried down into the recesses of the lower die. It is thus bent to form the shape shown in Fig. 6, in which the blank includes two attached prongs which have received approximately their final form. By a further operation the blank shown in Fig. 6 is severed at the middle, by means of a cutter or die D of any suitable constructionand which may or may not be carried bythe upper die A. The severing of the blank shown in Fig. 6 may be performed by a separate operation, but it is most convenient and expeditious to accomplish this by the same stroke of the press. For this pur pose the cutter D is conveniently carried by the upper die A, being a projection from the intermediate portion 72. thereof and which, to ward the end of the stroke of the upper die, cuts through the middle portion of the double blank, for which purpose it may enter a recess D in the middle portion 9 of the lower die, the parts D and D thus co-opera-ting as a shear to cut out a small piece of scrap which drops down through a clearance opening 2' in the lower die. Similarly the scrap produced by the shearing action of the cutter C and socket C also drops down through a clearance opening 9'.

As the two dies finally come together, they give the now-severed blanks a final pinch which imparts to them their precise contour. In so doing it is desirable that at k the stock be bent to a fairly sharp corner, as this is the portion which eventually will rest upon the surface of the prong carrier-plate when the prong is riveted to the plate. This is shown in Fig. 4, where the shank m of the prong is passed through the plate and its end swaged .down to form a rivet head beneath. In Fig.

4 the prongs are designated E, E, and their carrier-plates F, F. These plates are shown as having a direct rocking engagement at their inner edges and being forced toward each other by a spring-plate G, which is of usual construction.

Thus it will be seen that the method comprises the cutting from the stock of a suitable length of wire, the bending of this into a double blank of yoke form, as shown in Fig.

6, and then cutting this in two at the middle to form two complete prongs, as shown in Fig. 7. The blank (Fig. 6) might be given the exact curvature of final contour of the two prongs before it is severed; but, for convenience in accomplishing the entire method at one stroke of the press, it is desirable to perform the severing ust preceding the final pinch which gives the prongs their set shape.

The wire stock is usually flattened or of approximately elliptical cross-section,and the dies may be grooved to receive such stock, as is apparent from the cross-section, Fig. 2.

It is customary to make the mating ends of the prongs with interfitting notches so that, when closed together, they shall interfit, as shown in Fig. 5. This notching is accom-" plished by the cutter C in association with the so lower die C, each having the contour shown in the plan view, Fig. 3. Thus the one cutter serves for thus notching the ends of both prongs so that, when mounted on their plates and assembled, the prongs may fit properly together.

It is desirable that the dies be so proportioned that the projections or bosses f, 7 shall come into contact with the wire blank immediately upon its severance by the cutters C, C. It-results that the cut-off portion of the blank is at no time free or unsupported. The instantit is severed, it receives the pressure of the bosses f, f above, while still held at its ends on the shoulders p, g of the lower die. A slight further movement of the upper die bends the middle portion of the blank down upon the middle recess g' of the lower die; this amounts to clamping the middle portion of the blank (due to its stiflness) between the two dies, so that the continued movement of the upper die bends the blank to both sides of its middle to quite the same efi'ect as if the middle were clamped fast between upper and lower members. It results from this that the bending of the blank draws both of its end portions toward the middle so that, when finally shaped, it occupies the position in the lower die shown in Fig. 1. This is true irrespective of the action of the middle cutter D which, if rigidly carried by the upper die, further holds the middle portion of the blank from the instant when it begins to penetrate it. After the upper die has ascended to a suitable height, the severed blank,now constituting two prongs,is removed from the lower die, for which purpose any usual known ejector may be provided.

The invention is applicable for the production of prongs or binder elements of other shapes than the half-rings shown. The invention may be modified in any way within the skill or judgment of mechanics or constructors according to any existing requirements. I

I claim as my invention:

1. A method of making prongs for binders consisting in cutting off a length of wire suitable for two prongs, then bending the 1 wire on both sides of its middle-portion to prongs, and finally severing the blank at its middle whereby two separate prongs are simultaneously formed.

3. A method of makin prongs for binders consisting in cutting 0 a length of wire suitable for two prongs, engaging the blank between opposite dies whereby it is clamped fast at its middle portion, then bending the severed blank at both sides of the clamped middle portion to form the curved portions of the prongs, and finally severing the blank at its middle whereby two separate prongs are simultaneously formed.

4. An apparatus for making prongs for binders comprising upper and lower dies adapted to grip between them and bend a length of wire corresponding to two prongs, the dies having coinciding strai ht middle portions and symmetrically curve reciprocal portions on opposite sides thereof adapted as they come together to bend the blank into the curved form of two prongs, and a cutter at the middle portions of the dies for severing the blank into two separate prongs.

' 5. The apparatus of claim 4 with a cut ter for cutting off the wire to leave a blank of suitable length in position for bending between the dies.

6. An apparatus accordin ing a stop for limiting the eed of the wire stock on one side of the dies and a cutter on the other side of the dies for severing the stock, whereby to leave between them a length of wire suitable for forming two prongs.

7. An apparatus for making prongs for binders, comprising means for feeding the wire stock for a len h suificient to form two prongs, a cutter or severing the stock, dies for gripping the blank on opposite sides adapted to bend the severed blank on both sides of its middle portion to form the curved portions of two prongs, and means for finally severing the blank at itsmiddle whereby the two prongs are separated.

8. An apparatus for making prongs for V binders, comprising means for feeding and cutting 01f a length of wire suitable for two prongs, opposite dies enga ing the wire between them, whereby the blank is clamped fast at its middle portion, means for bend'-' ing the severed blank at both sides of the severing the blank at its middle, whereby two separate prongs are simultaneously formed.

In witness whereof, I have hereunto signed my name.

CLARENCE D. TRUSSELL.

to claim 4 havclamped middle portion toform the curved portions of the prongs and'mean's for finally

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