US2071079A

US2071079A - Method of making safetypins

Info

Publication number: US2071079A
Application number: US11957A
Authority: US
Inventors: Magidson Frank
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-03-20
Filing date: 1935-03-20
Publication date: 1937-02-16
Anticipated expiration: 1954-02-16

Description

Feb. 16, 1937. F. MAGIDSON METHOD OF MAKING SAFETYPINS Filed March 20. 1955 2 (DH-2a NVENTOR Patented Feb. 16, 1937 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates to safety pins of the unitary type, i. e., pins made from a single length of wire stock, and to methods of making the same.

An object of this invention is the provision of a safety pin that shall be of unitary construction, strong, efficient and durable.

Another object of the invention is the provision of a unitary pin that may be manufactured at lower cost than prior art pins having a separately formed head and guard, and which may be more easily manufactured than such prior art pins, and which admit of continuous and uninterrupted production on automatic machines.

A further object of the invention is to provide a method of gathering metal at the end of a wire, which will insure that a sufficient amount of metal may be available at the proper place to permit the formation of a head on the safety pin that will have adequate size and clearances to retain the pin point in a safe position when closed or locked.

Other objects of the invention will in part be apparent and will in part be obvious from the following description taken in conjunction with the accompanying drawing in which:-

Figure 1 is a more or less diagrammatic view of apparatus employed in feeding wire stock to a gathering die which forms a gather or ball of metal from which the cup or head of the safety pins are formed in accordance with this invention;

Figs. 2 to 6, inclusive, show a series of steps employed in the manufacture of safety pins in accordance with this invention, Fig. 6 depicting both the last step and the finished pin;

Figs. '7 to 11, inclusive, show another series of steps which may be employed in the manufacture of pins in accordance with this invention, the steps depicted by Figs. 10 and 11 being the reverse of the steps depicted by Figs. 5 and 6, Fig. 11 depicting both the last step and the finished pin;

.Fig. 12 is a bottom View showing the shape and form of the cup of the pins as formed by the steps depicted in Figs. 3 and 8;

Fig. 13 is an end view of this cup as seen looking in the direction of arrows XIIIXIII; and

Fig. 14is a view showing a modified form of pin which may be made in accordance with this invention.

Throughout the drawing and the specification, like reference characters indicate like parts.

Forconvenience, the article, that is,. the safety pins of this invention, will first be described as it is believed that the description of the methods of making the same and their advantages may then be more easily understood.

In the drawing, twoforms of safety pins are illustrated, one form being shown in Figs. 6 and 11 and the other in Fig. 14. Since the method involved in the making of the pins of Figs. 6 and 11 and 14 differ in certain steps, these pins are designated by reference characters I, I and 2, respectively. I

Since pins I and I are similar in shape and form corresponding parts will be designated by the same reference characters. Pins I and I' are each unitary in construction, being made from a single length of wire, for example, spring steel, and comprise a back bar 3, a bar pin 4 having a pin point 5, a coil spring portion 6 and a head I. Head 1 comprises a cup 8 of channel shape having spaced relatively deep lips 9, a. closely bent return-loop ID of substantially U- shape and a guard II which extends from the back bar 3 into the cup 8 but in spaced relation to the bottom and lips thereof. that the guard II shall extend at right angles to the back bar and enter cup 8 at about its middle. The guard I I and loop II) are so formed that the pin point 5 may enter the cup from either side of the guard when closing the pin and so that the pin point may pass under the guard to facilitate opening thereof.

In forming the pin, the bar pin 4 is made of such length that the extreme point of the pin will project a slight distance past the rear end of the cup as indicated at I2 in Figs. 6 and 11. When the cup is formed, the groove or channel defined by lips 9 extends beyond the lips and into the lower bar of loop II), as indicated by broken line I3. This extended groove serves to. further increase the seating surface for the pin point and to further protect the same.

From the above, it is seen that the safety pin is unitary throughout as all parts thereof are formed from the same piece of stock. It will also be observed that because of the closely bent return loop I0, a strong head is provided which is highly resistant to the forces imposed thereon by the spring of the bar pin which tends to distort and bend the head. To further increase the stiffness and strength of the head, it is preferred to make the return bend loop ID as short 'as possible in respect to dimension L.

PinZ differs from pins I and I merely in the shape of the loop which joins the cup to the guard, and for this reason similar parts will be designated by prime reference characters. Cup 8 is joined to guard I I by means of a-loop I5 which It is preferred is substantially circular and of a diameter materially less than the distance between the back bar 3' and bar pin 4'. By making this loop of small diameter, sufiicient stiffness and strength are provided to nullify the normal bending loads imposed thereon when the pin is closed. As stated previously, it is this bending load which tends to distort and open the heads of safety pins.

The method employed in the making of pin l includes among other things the accumulation or gathering of a ball [6 on the end of a wire that shall contain sufficient metal from which to make cup 8 of the safety pin. This gather or ball is formed by a cumulative and progressive action which consists in upsetting, in incremental steps, short lengths of wire, until a sufficient volume. ofv metal is contained in the ball or gather from which the cup 8 may be made. The cup is formed by placing the ball in a suitable die which is shaped to form the lips 9 and the channel or groove defined thereby. The gathering operation comprises feeding wire stock from a source of supply, such as a coil of wire l6, into a gathering die I! comprising gripping jaws 18' and an upsetting member I9. The jaws and member l9 may be grooved to form a cavity of the shape which it is desired for the gather or ball I6 to take. The wire may be fed by means of pinch rolls 20 adjusted to feed the wire in uniform increments into the gathering die. When the wire has been advanced an increment it is gripped between jaws l8 and the end ofthe wire projecting beyond the jaws is struck by member 19 and upset. This procedure is repeated until a ball or head l6 has i been formed at the end of thewire containing enough metal from which cup 8 may be shaped. When forming the gather of metal above described, it is preferred that the increment of feed into the gathering die shall be not greater in length than approximately the diameter of the wire. In some cases, better results may be obtained with shorter increments of feed. I have also found that the amount of metal required to form cup 8 is approximately equal to not-less than four times the amount of metal contained in a length of four diametersof the wire. This amount of metal may be increased if necessary by increasing the number of upsetting operations;

The character of the metal in the wire also has to do with the amount of metal which must'be gathered and the number of gathering steps employed. If the wire is of high grade spring steel, the length or increment of wire which maybe upset with one blow of member l9 may be less than the diameter of thewire, whereas if the metal is easily upset, longer incrementsmay be upset with each blow of member 19.

In forming the gather illustrated in the drawing, in spring steel wire, I have employed five upsetting steps and the length of wire upset in each step has been equal to one diameter of the wire. However, these specific lengths of feed and number of upsetting operations are merely examples which are given by way of explanation and are not intended to be limiting in scope, as the procedure may be modified to suit the particular conditions at hand and the results to be accom plished. For example, I have found that in making pins from wire of p.034 inch in diameter, the amount of metal accumulated in the gather or ball from which cup 8 ismade shouldbe equal to the volume of metal contained in a length of four diameters of such'wire. I have found also that larger wire diameters, a suff cient amount of metal may be accumulated in the ball or gather IS with a small number of upsetting steps. In any case the amount of metal accumulated in gather [6 should be such that when it is struck in a die the maximum depth of cup 8 will be of such value that the highest points on the lips 9 of the cup will project upwardly a distance greater than the diameter of bar pin 4 and above the lower end of guard H.

When the ball or gather has been formed, the wire is cut as with shears 22, to the length required to make a pin, and thislength with its gather may be called a pin blank. The blank having been formed, point 5 is ground thereon. After the pin blank has been pointed as in Fig. 2, the blank is then manipulated to form the head 8. This is done by forming a right angle bend in the blank as indicated at, 23. and this bend forms the guard for the pin. Cup'8 is formed in a die and the bending and cupping may be done simultaneously 'or separately in any order desired. The cupped portion of the blank is then given a right angle bend as, at 24 in Fig. 4. After bending the pin blank in this fashion it is coiled around mandrel 25 to form the coil spring portion, after which.

the cupped end of the pin-blank is bent and closed on the pin point. Thus; the last operation completes the headand closes the pin.

In making pin I, the first three steps depicted by Figs. 7. 8 and 9 are the same as the first three steps depicted by Figs. 2, 3; and 4 employed in making pin I. When the pin blank has been bent to the shape shown in Fig. 9, the head is completed by forming the close bend loop 1., When the head has been formed, the pin blankisbent arounda mandrel 25 to form the coil 7 spring portion, and incompleting this coil spring the bar pin is bent past the head so that when it is released, it seats in the cup 8 thereof and the circular shape about a mandrel or pin. The head havingbeen formed, the body of the pin blank is then bent around a mandrel or pin to form the coil spring portion. In making pin 2, the head maybe completed prior to forming the coil spring portion and closing the pin, or the coil spring portion may be made first as in Fig. 5, andthen thehead completed so that on completion of the head the pin is closed or locked.

Having thus described my invention, what I claim' as new and desire to secure by Letters Patent is:

1. In a methodof making safetypins from a single piece of wire, the steps of upsetting a length of such wirenot greater than its diameter, repeating such upsetting until a head'is formed containing a quantity of metal equalto at "least four times the amount of metal contained in a length of one diameter of said wire, then cupping the headlengthwise of the pin to form a seat for the point thereof. 7

2. Ina method of making safety pins from'a single piece of wire, the steps of upsetting, in a series of uniform .steps a head on the endof the wire untilit contains a volume of metal equal toat least four times the amount of metal con tained in a lengthofat least four diameters thereof, each upsetting step involving the. up

setting of a length equal to not greater than the diameter of the wire, forming a clip in said head extending lengthwise of the wire, bending the wire adjacent the cupped end to form a return bend loop and a guard leg extending from within and at right angles to the cup and then so advanced, continuing such advancing and upsetting until a head has been formed which contains a quantity of metal at least equal to the quantity contained in a length of four diameters of such wire, then in cutting a length of wire sufficient to form a safety pin, then in cupping the upset head to form a seat for the point of said pin, then in bending the cupped end of the wire upon itself, bending the wire to form a guard which extends from between the lips of the cup to the back bar of the pin.

4. In a method of making the cup and guard of safety pins made from a single piece of wire stock which consists in advancing wire stock in incremental steps, upsetting each increment so advanced until a head has been formed containing substantially the same amount of metal that is contained in a length of at least four diameters of said stock, cutting said wire to the length required by the pin, then in cupping said head longitudinally of the wire, and then in shaping the cupped end of the wire to form a return bend portion containing the cup and a guard portion extending from within and centrally of said cup to the back bar of the pin.

5. In a method of making the cup and guard of safety pins made from a single piece of wire stock which consists in advancing wire stock in incremental steps, upsetting each increment so advanced until a head has been formed containing substantially the same amount of metal that is contained in a length of at least four diameters of said stock, cutting said wire to the length required by the pin, then in cupping said head longitudinally of the wire, and then in shaping the cupped end of the wire to form a relatively short' return bend portion containing the cup and a guard portion extending from within and centrally of said cup to the back bar of the pin.

6. In a method of making the cup and guard of safety pins made from a single piece of wire stock which consists in advancing wire stock in incremental steps, upsetting each increment so advanced until a head has been formed containing such a quantity of metal that when a cup is formed therein the depth of the cup will be suflicient to accommodate the point of the pin and the lower end of the guard, cutting said wire to the length required to form the pin, then in cupping said head longitudinally of the wire, and then in shaping the cupped end of the wire to form a return bend portion containing the cup and guard portion which extends from within the cup to the back bar of the pin.

FRANK MAGIDSON.