US2728190A - Sheet metal link and chain made thereof - Google Patents

Description

m 1955 w. BISCHOFF 2,723,190

SHEET METAL LINK AND CHAIN MADE THEREOF Filed March 8, 1955 (V/22% Edw I G-M E? is gyfi 3 the inherent resilience of the comparatively thin material of which the link is composed, render the wedging ele-' ments 13 of all the combined links capable of performing the dual functions of automatically increasing the stillness of the chain when it is bent beyond a certain degree of curvature and of locking the respective links in assembled engagement with adjoining links. The precise manner in which these useful functions are performed will now be described.

The mode of link assembly in making up the chain in its square cross-section form should be understood by referring to Fig. 4 in particular. Assuming that the two links shown edgewise in that figure next to the two broken links at the right end of the chain section are the first links in a new chain, these two edgewise links are held in closely abutting relation instead of angularly arranged as shown. Then, one other link is turned at right angles to the two first-mentioned links and is hooked through registering side slots 12 at one side of the medial slots 11 of said two links, which operation will bring the ends of the corresponding arms of the latter into medial slot 11 of the said other, or third-mentioned, link. In doing this, the upturned wedging element 13 of the third-mentioned link will not pass freely through the side slots 12 of the first-mentioned links, because the vertical projection of said upturned wedging element exceeds the width of each side slot 12. It is necessary, therefore, to squeeze the front edge portion of the third-mentioned link between the jaws of a pair of tweezers, or pliers, and thereby partially flatten the link until the vertical projection of wedging element 13 is reduced so that it will pass through slot 12. In assembling a fine chain, a holding tool, such as tweezersor pliers, is required to pick up and manipulate each link, so it is the practice to engage the front portion of each link at the angle between its body 10 and wedging element 13 by the jaws of the same, so the application of sufiicient pressure for securely gripping the link will serve to flatten out the angle of upturn enough to permit said wedging element to clear the edges of side slot 12. After the third-mentioned link has been threaded through the sideslots 12-12 of both first-mentioned links and the holding tool has been disengaged with the former, it will spring back into its original form and wedging element- 13 thereof will become locked automatically against disengagement with the two first-mentioned links. Re-use of the holding tool will be required thereafter to disassemble any link from locked engagement with other adjoining links in the chain.

After the third-mentioned link has been assembled in interlocking engagement with the two first-mentioned links, a fourth link is paired up with said third-mentioned link by threading it through the remaining unoccupied and registering side slots 12.12 in said two first-mentioned links, and in the same way with the aid of a holding tool. until the desired length of chain is completed. As each pair of additional links become assembled, it is the practiceto rotate the chain through an angle of ninety degrees to facilitate assembly of the succeeding pair of links.

The manner in which the wedging elements 13 automatically stiffen the chain when flexed laterally to a degree exceeding that of normal use in a large radius articlepof jewelry, such a necklace, will be understood u pon particular reference to Fig. 6. For instance, supposingthat the upper and lower links of the pair represented in full lines become oscillated during lateral flexion ofthe chain on a vertical axis, the wedging elements of said links will become frictionally engaged with the abut tingedges-of the respective side slots 1212 in one of the rightand left pair of links shown in cross-section dependingupon the direction of fiexion. The result will be progressively increased frictional resistance to fiexion as the wedging elements become more deeply wedged into the side slots. Upon restoration of the chain to a more Thereafter, the process is repeated as described nearly straight condition, frictional resistance will be relieved and the chain will become fully flexible again.

In order to convert the originally square chain C shown in Figs. 4 to 6 into a chain of pleasingly round cross-section, such as that shown in Fig. 7, the square chain is inserted between the forming dies 1414 which have semi-cylindrical opposed faces of appropriate diameter, while being held with the diagonals of its square crosssectional form at an angle of forty-five degrees to the direction of movement of the dies. When the dies 1414 are then closed on each other, they will press the chain into round form as at C, in which action the links of the chain become deformed without detracting from the ornamental appearance of the chain as a whole.

Dies 15-15 having semi-elliptical faces are employed to convert a square chain C into a chain of elliptical cross- .section as at C". Before the dies are closed, the square chain C must be held with one diagonal in alignment with the direction of die movement.

It is to be understood that the present disclosure of the invention is an illustrative example and that various changes, modifications and alterations may be made in these structural embodiments which do not constitute departures from the spirit and scope of the invention.

I claim:

1. As an article of manufacture, a chain link comprising a substantially C-shaped body having a stern and parallel arms with a medial slot therebetween which is open at its end opposite to said stem, and a substantially triangular wedging element projecting from the stern of the body opposite to said medial slot with. its nose facing away from the latter, the arms of the body being provided with closed side slots arranged substantially parallel to said medial slot and being slightly greater in length than the distance between the nose of the wedging element and the inner end of said medial slot. i

2. As an article of manufacture, the chain link defined in claim 1, wherein the body is curved in the direction of the arms and slots.

3. As an article of manufacture, the chain link defined in claim 2, wherein the wedging element is bent oppositely with respect to the concave side of the curvature of the link body.

4. As an article of manufacture, the chain link defined in claim 3, wherein the body is made of thin resilient material and the projection of the wedging element angularly from the chord of curvature of the body exceeds the width of each side slot.

5. As an article of manufacture, the chain link defined in claim 1, wherein the body is made of thin resilient material and the projection of the wedging element angularly from the chord of curvature of the body exceeds the width of each side slot.

6. As an article of manufacture, the chain link defined in claim 1, wherein the medial slot is at least twice as wide as each side slot. I

7. An auto-stiffening chain comprising plural interengaged links of identical structure, each link including a substantially C-shaped body having a stem and parallel arms with a medial slot therebetween which is open at its end opposite to said stem and a substantially triangular wedging element projecting from the stem of the body opposite to said medial slot with its nose facing away from the latter, the arms of the body being provided with closed side slots arranged substantially parallel to said medial slot and being slightly greater in length than the distance between the nose of the wedging element'and the inner end of said medial slot, in the interengaged rela tion of the several component links of the chain the latter being arranged in side-by-side pairs with the links of each pair rotated aboutthe chain axis substantially ninety degrees relative to the links of the next succeeding pair and having the arms of each link of any pair threaded through the registering side slots in corresponding arms of links of an adjoining pair, whereby the arms of both links of each pair are abuttingly confined in the registering wherein the body of each link is curved longitudinally medial slots of the adjoining pair of links, the chain thus with the convex surface facing in the same direction as the produced being substantially square in cross-section. angular bend in the wedging element.

8. An auto-stiffening chain as defined in claim 7, wherein each link is made from thin resilient material 5 Reffilwces Cited in the file Of this Patent and the wedging element of each link is bent angularly UNITED STATES PATENTS with respect to the link body to such a degree that the projection of said element away from the body is greater g g than the width of each side slot in the body arms. 2 169265 Magmz A 1939 9. An auto-stifiening chain as defined in claim 8, 10

Images