The ninth operation (illustrated in Fig. 9) is to bring the middle portion of each link—that is to say, the side members and the cross stay—to the finished rounded form, which is also performed by means of a pair of dies or swages.
The tenth and last operation (illustrated in Fig. 10) is to contract the link slightly in the lateral direction in order to correct any imperfections at the sides left by the two previous operations and bring the link to a more perfect and stronger form, as shown. This operation has the important result of strengthening the link considerably by contracting or rendering more pointed the arched form of the bow or end of the link, and also by thickening the metal at that part where the wear is greatest, this thickening of the metal at the ends of the link occurring in the direction of the line of strain (as indicated by x in Fig. 10) and being brought about by the compression or "upsetting" of the metal at the end of the link. It may be preferable to perform this operation immediately after the seventh operation, and I reserve the right to do so.
In the case of large cables only the metal is preferably heated for the eighth, ninth, and tenth operations.
I will now refer to the figures which illustrate the series of tools whereby the above mentioned operations are performed.
Fig. 1a shows a plan (the punch being in section) and Fig. 1b an elevation of the bed die of the tool by which the notches b of the first operation are performed. The feed mechanism is not shown, but might be of any ordinary intermittent kind. g is a groove in the bed, in which lies the lower vertical web of the rod, of cruciform section, the two horizontal webs lying upon the bed with the edge of the web to be notched lying just over the die, in which works the punch, B, of which B' is the cutting edge. The punch is operated in the usual way, its lower end, which does not rise out of the die, acting as a guide. B* is the beveled stop in the groove, g, which by fitting in the notches, b or b', corrects inaccuracies of the feed.
FIG. 1a.
FIG. 1b.
Fig. 2a is a sectional plan and Fig. 2b an elevation of the tool by which the second operation is performed, the same tool being also used for performing the third operation. (Illustrated in Fig. 3a.) h h are a pair of bed-dies having a space h' between them to receive the lower web of the bar, and having notches, C C and D D, in their inner ends, forming counterparts of the punches by which the pairs of mortises, c d, Fig. 2, are punched in the pair of webs lying upon the bed-dies, h. These bed-dies are fitted to slide a little in opposite directions upon a suitable bed plate and are caused by the inclined cams, i', on the guides, i, of the press head (which pass through corresponding apertures in the bed-dies, h) to approach each other at the moment the punches come down on the work, so as to grip the lower web of the rod and support the pair of webs being operated on close up to the sides of the lower web lying in the space h', while when the punches rise the bed-dies move apart, so that the web is quite free in said space h' and the rod may be easily fed forward for a fresh stroke of the press. B* is the beveled stop in the space, k', as in the tool first described. The bed-dies h have a second set of notches C' D' at their outer ends, similar to but longer than those C D, so that by reversing the bed-dies they will form counterparts for a second set of punches corresponding thereto for performing the third operation—i.e., enlarging the mortises, c d, as represented in Figs. 3 and 3a; or, instead of adapting the dies, h, to perform the two operations, separate tools may be used for the second and third operations.