US2732733A - Spring device provided between the - Google Patents

Description

Jan. 31, 1956 J M JoNssoN 2,732,733

SPRING DEVICE 'PRO'VIDED BETWEEN THE CHEEKS or A PAIR OF PLIERS OR A SIMILAR TOOL Filed 00:. 20, 1954 United St Patent SPRING DEVICE PROVIDED BETWEEN THE CHEEKS OF A PAIR OF PLIERS OR A SIM- ILAR TOOL The present invention relates to a spring device between the cheeks of a pair of pliers or a similar tool, preferably a pair of saw set pliers, comprising a leaf spring provided between the handle portions of the cheeks and actuating these automatically from each other. The invention is substantially characterized thereby that the leaf spring is substantially S-shaped with bent-out end portions, the said end portions being bent approximately at right angles to the middle portion of the leaf spring which with one end portion is stationary in a recess or the like in the outer edge of one of the cheeks near the meeting cheek portions, thus relatively near but at some distance from the common pivot pin of the cheeks, the leaf spring being with its other end portion movably inserted in a recess or the like in the interior of the other cheek and at the handle portion of the cheek near its outer end. The bent-out end portions of the S-shaped leaf spring should preferably be of such a size that when the cheeks against the action of the spring are pressed together as much as desired, and the stationary end portion of the spring, along a periphery, the centre of the circle being located in the pivot pin, has passed a connecting line drawn from the pivot pin to the recess of the movably inserted end portion of the spring, there will arise an extra tension in the spring, brought about when the cheeks are pressed together, which in the form of an accumulated tension, when the checks are relieved after having been pressed together, quickly moves the checks from each other and to their original position again, without risking that the bent spring, when used for a long time, shall tend to crack at some point between the end portions of the spring, as is the case when a substantially U-shaped or angularly bent spring is concerned.

Also a modification is suitable, that is, that the stationary end portion of the spring and the movably inserted end portion of the spring are provided on the said alternative checks in a sequence contrary to the abovementioned, or that the end portions are both stationarily attached to the respective cheeks.

The accompanying drawing illustrates an embodiment of the invention.

The figure shows a side view of a pair of pliers provided with the spring device according to the invention, for example a pair of saw set pliers of the kind described in theSwedish Patent No. 144,136.

Referring to the drawing 1 and 2 designate the cheeks of a pair of pliers pivoted on a pin 8 and provided with a leaf spring 3 provided between the handle portions of the cheeks 1, 2 and actuating the handle portions automatically from each other. The leaf spring 3 is substantially S-shaped with bent-out end portions 4, 5, which are bent approximately at right angles to the middle portion of the spring 3. The spring 3 is with one end portion 5 in the embodiment shown stationary in a recess 6, a hole or the like in the outer edge of the cheek 2, near the 2 meeting cheek portions, thus, near but at a suitable distance from the common pivot pin 8 of the cheeks 1, 2. The spring 3 is with its other end portion 4 movably inserted in a recess 7 or a hole or the like in the interior of the other cheek 1 and at the handle portion of the cheek near its extreme end.

The bent-out end portions 4, 5 of the substantially S- shaped spring 3 have such a relative size that, when the cheeks 1, 2 are pressed together against the action of the spring 3, as much as is desired, the stationary end portion 5 of the leaf spring 3 has, along a circle line a the centre of the circle being located in the pivot 8, passed a connecting line b drawn from the pivot 8 to the recess 7 of the movably inserted end portion 4 of the leaf spring, whereby an extra tension arises in the spring 3 effected during the compression of the cheeks 1, 2, which in the form of an accumulated tension, when the cheeks are relieved after being pressed together, strongly and quickly moves the cheeks 1, 2 from each other and back to their original position. The said tension also depends thereupon that the end attachments of the spring 3 have obtained at smaller distance between them, when the cheeks are pressed together, whereby also the end portions 4, 5 are additionally retained in their attachments 6, 7 when the cheeks 1,. 2 are pressed together. The special spring 3 according to the invention also eliminates the risk that the bent spring 3 shall tend, when used for a long time, to crack at some point between the end portions of the spring owing to the change of shape when the spring is strained to a somewhat reduced S-shape, which is the case as regards earlier known U-shaped or angularly bent springs.

The details described above can be modified within the scope of the invention. For example the attachments for the end portions 4, 5 of the spring can be reversed relatively to the cheeks, or both end portions 4, 5 can be stationarily attached to the respective cheeks 1, 2.

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

1. In a saw set or like tool, the combination comprising first and second cheeks, pivot means connecting said cheeks together at their end portions for movement toward and away from each other, and a substantially S-shaped leaf spring interposed between said checks for urging said cheeks apart, said spring having oppositely bent-out end portions extending approximately at right angles to the middle portion of said spring, means attaching a first one of said end portions to the inner side of said first cheek substantially at the location where it meets said second cheek when said cheeks are in their initial spread-apart condition, and means attaching the second end portion of said spring to said second cheek at a point further from said pivot means than is said first end portion, the entire length of said spring being located to one side of a line between said pivot means and the point of attachment of said second spring end portion to said second check when said cheeks are in their initial spread-apart condition, and said first end portion of said spring upon moving said cheeks towards each other being relocated to a position to the other side of said line and decreasing the distance between the ends of said spring thereby effecting an increase in bending of said end portions of said spring.

2. A tool as defined in claim 1 wherein said first end portion of said spring is stationary with respect to its attachment to said first cheek, and said second end portion of said spring is movable within limits with respect to its attachment to said second cheek.

3. A tool as defined in claim 1 wherein said first end portion of said spring is movable within limits with respect to its attachment to said first cheek, and said second end portion of said spring is stationary with respect to its attachment to said second cheek.

4. A tool as defined in claim 1 wherein both end portions of said spring are stationary with respect to their attachments to said checks.

References Cited in the file of this patent UNITED STATES PATENTS Hopkins May 8, Fischer May 26, Sylvester Nov. 9, Jacobs Oct. 5, Young Mar. 15,

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