US2261424A

US2261424A - Safety pin

Info

Publication number: US2261424A
Application number: US308336A
Authority: US
Inventors: George S Watson
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-12-09
Filing date: 1939-12-09
Publication date: 1941-11-04
Anticipated expiration: 1958-11-04

Description

Nov. 4, 1941. G s A ON 2,261,424

SAFETY PIN Filed Dec. 9, 1939 INVENTOR George 6. Wafison Patented Nov. 4, 1941 UNITED STATES PATENT OFFlCE SAFETY PIN' George S. Watson, Winnetka, 111.

Application December 9, 1939, Serial No. 308,336

3 Claims.

This invention relates to safety pins and is more particularly concerned with an improved safety pin which will not open under excessive strain.

Conventional type safety pins possess the disadvantage of opening when subjected to pulling and straining. When a pulling force is applied to the piercing arm of the pin, the arm bends outwardly, causing the end thereof to slip out of the clasp.

I have discovered that this disadvantage, inherent in present types of safety pins, can be entirely avoided by making the piercing arm slightly longer than has been customary and by bending the arm inwardly or concavely adjacent the middle thereof so that when strain is applied thereto, the arm tends to straighten and lengthen instead of bend and shorten. Moreover, by lengthening the piercing arm of the pin, the point thereof is forced against the opposing inner wall of the clasp before the arm is pulled into a substantially straight line position, thereby offering increased resistance to further bending of the arm and further assuring that the pin will remain closed.

In order to more fully understand the invention, reference should be had to the following detailed description and the accompanying drawing of which Figure 1 is a diagrammatic View of a safety pin in open position embodying the invention;

Figure 2 is a diagrammatic view of a modification of the invention, and

Figure 3 is a diagrammatic representation of the pin shown in Figure 1 but in closed position.

Referring to the drawing, numeral I indicates generally a safety pin made out of spring steel or other suitable materials ordinarily used in the manufacture of such pins. tened to the end thereof a clasp 5 of conventional construction. The other end of the safety pin is provided with a loop I to give the desired springiness to the piercing arm 9. The piercing arm 9 is bent at the point ll so that the portion l3 of the arm between the point H and the point I5 is at an angle to the portion l1 between the loop I and the point ll. As shown in the drawing, the angle at which the portion I3 is bent is between approximately 25-30".

Referring more particularly to Figure 3 which shows the pin in closed position, it will be seen that the length of the piercing arm 9 is such that when the pin is closed the point l5 reaches almost to a point IS on the inner wall of the clasp 5 where the wall abruptly turns downwardly.

The arm 3 has fas- When the pin is in closed position the arm ll straightens out somewhat so that the angle be tween the portion l3 and a straight line coincidental with the portion I1 is less than the angle between these portions when the pin is in open position. When pull is exerted outwardly on'the arm 9, it tends to straighten out, thereby increasing its length and thereby'pushing the end of the piercing arm further into the clasp, rather than tending to draw it out of the clasp as is the case with conventional type pins. Before the arm 9 reaches a straight position, however, the point 15 abuts the point IS in the clasp and offers increased resistance to further bendin the arm, thereby enabling the pin to withstand far greater stresses and strains than is possible with conventional type pins.

Since the maximum strain on the piercing arm usually occurs adjacent the center of the pin, in my preferred construction I bend the arm at a point approximately at the center of the piercing arm. However, instead of bending the piercing arm at point II as shown in the drawing, the entire arm may have a gradual concave bend, as shown in Figure 2. By bending the pin at a point approximately at the center of the arm, this bend itself offers increased resistance to pulling and straining which is ordinarily greatest at this point. Furthermore, by placing the bend at approximately the middle of the arm, the possibility of the strain all being directed at this point is substantially avoided or greatly lessened since the material which is pinned is prevented from being bunched at this point, as ordinarily happens with conventional pins when the arms bends outwardly under excessive strain. Instead, the tension of pulling is more concentrated adjacent the point end or the loop end of the pin which are able to stand much greater strains before bending action occurs.

The bend in the piercing arm does not materially lessen the capacity of the pin for holding materials for the reason that the arm straightens out to a large extent when it is clasped, the amount of straightening being directly dependent upon the type of material from which the arm is made. With steels or other metals or alloys having high elasticity, the amount of straightening, of course, is less than in the case of those materials which have lower elasticity.

It will be seen, therefore, that by bending the piercing arm of the pin inwardly or concavely at a point approximately at the middle thereof and by making the piercing arm long enough so that the point end thereof abuts the opposing wall of the clasp prior to the time that the arm reaches a straight position, I have been able to greatly strengthen the safety pin without altering the nature of the materials from which it is made, and thereby greatly lessen the danger and disadvantage inherent in the usual type of safety p The pin shown in Figure 2 is a modification of the invention shown in Figures 1 and 3. As shown, the piercing arm 9 as Well as the arm 3' both have a gentle concave contour, the bend being approximately the same for both arms. By providing the pin with a gradual bend, the tendency of the cloth or other material through which the piercing arm passes, to bunch at either end of the pin is considerably lessened, particularly in view of the fact that the piercing arm as well as the arm 3 to which the clasp 5' is fastened, substantially straighten out under tension. As in the case of the pin shown in Figures 1 and 3, the length of the piercing arm 9 is such that the point reaches almost to the point I9 where the wall of the clasp turns abruptly. In this modification the distance between the two arms is substantially as great as it is in the case of conventional pins and therefore the capacity of the pin is just as great.

It will be apparent that if pull or strain is applied to the arms 3 and 9' in opposite directions, the arm 3' tends to shorten and the arm 9' tends to lengthen, thereby doubly insuring that the end of the arm 9 will not slip out of the clasp. As in the pin shown in Figures 1 and 3, the point [5 abuts the wall of the clasp before the piercing arm 9 completely straightens out.

I claim:

1. A safety pin comprising an elongated arm upon one end of which a clasp is supported, and an elongated piercing arm made of spring steel or similar alloy, bent in such manner that when in closed position a point intermediate the ends of said piercing arm is closest to the first mentioned arm and the ends of th piercing arms are most remote therefrom and the portions between said closest point and ends gradually recede from said first mentioned arm, said clasp having one wall extending in the same direction as said piercing arm, and a second wall which is at an abrupt angle to said first mentioned wall in the path of movement of the point of said piercing arm, the point end portion of said piercing arm lying against said first mentioned wall and the point end of the piercing arm reaching almost to said second mentioned wall whereby when tension is applied to said piercing arm in a direction opposite from that of the first mentioned arm, the point end of said piercing arm abuts said second mentioned wall when the piercing arm is partially straightened.

2. A closed safety pin in accordance with claim 1 in which the point of said piercing arm which is closest to said clasp supporting arm is approximately in the middle of said piercing arm.

3. A closed safety pin in accordance with claim 1 in which the piercing arm has a gradual concave bend with the middle thereof closest to said clasp supporting arm.

GEORGE S. WATSON.