My invention has for its object the manufacture of weldless stayed chains, whereof each link, together with its cross strut or stay, is made of one piece of metal without any weld or joint; and the invention consists in producing a chain of stayed links from a bar of cruciform section by the consecutive series of punching, twisting and stamping operations hereinafter described, the punching operations being entirely performed on the metal when in the cold state.

Figs. 1 to 10 show the progressive stages in the manufacture of the chain, and the remaining figures show the series of tools that are employed.

The general method of operation of making stayed chains according to my invention is so far similar to the methods heretofore proposed for making unstayed chains from the bar of cruciform section that the links are formed alternately out of the one and the other pair of diametrically opposite webs of the rod, the links, when severed and completed, being already enchained together at the time of their formation.  The successive operations differ, however, in many important practical respects from those heretofore proposed, as will appear from the following detailed description of the successive steps in the process illustrated by Figs. 1 to 10.

I will distinguish the one pair of diametrically opposite webs of the bar and the notches and mortises punched therein and the links formed therefrom from the other pair by an index figure 1 affixed to the reference letters appertaining thereto.

a a are one pair of diametrically opposite webs, and a’ a’ the other pair of webs of the bar.

[Illustration:  Figures 2_a-b, 6a_, 4_a-b_, 7 a-b and 10 a-b
               MANUFACTURE OF WELDLESS CHAINS]

The first operation illustrated in Fig. 1 is to punch out of the edge of one of the webs, a, a series of shallow notches, b, at equal intervals apart, corresponding to the pitch of the links to be formed out of that pair of webs and situated where the spaces will ultimately be formed between the ends of that series of links.  The notches are made with beveled ends, and are no deeper than is absolutely necessary (for the purpose of a guide stop in the subsequent operations, as hereinafter described), so as to avoid, as far as possible, weakening the bar transversely.  This operation is repeated upon one of the pairs of webs a’; but whereas in the first operation of notching the web the “pitch” of the notches is determined by the feed mechanism, in this second operation of notching the notches, b, cut in the web, a, serve as guides to influence and compensate for any inaccuracy of the feed mechanism, so that the second set of notches, b’, shall be intermediate of and rigorously equidistant from the first set of notches, b.  This compensation is effected by the notches, b, fitting on to a beveled stop on the bed of the punching tool by which the notches, b’, are cut, the beveled ends of the notches, b, causing the bar under the pressure of the punch to adjust itself in the longitudinal direction (if necessary) sufficiently to rectify any inaccuracy of feed.  These notches, b b’, similarly serve as guides to insure uniformity of spacing in the subsequent operations of punching out the links.