Patent GB-191417826-A (GB)
Title: Improvements in Method and Machine for Making and Assembling Drive Chain Links.
Inventor: GILL HUBERT ALEXANDER
IPC: B21L9/00
Filed: 1914-07-28
Granted: 1915-07-28
Abstract: 17,826. Gill, H. A., [Locke Steel Chain Co.]. July 28. Making chains; bending - dies. - Links for sheet-metal drive chains of the type comprising side bars, small end bars and larger end bars or hooks, are made from a sheet-metal strip and assembled by a single pair of co-operating die blocks, each die block being provided only with elements immovably held relatively to each other. The upper dies are mounted in a block 37 carried by the slide 5 of an ordinary press which is reciprocated by an eccentric 16 on a shaft 8 connected to the driving-shaft 9 by gearing and a clutch. The lower die block 39 is solid and is fixed on the bed of the press. The strip is fed through straightening - rolls 34, Fig. 2, by a reciprocating gripper comprising a rod 33 and bell-crank lever 29 connected to a rod 30, which at its other end is coupled to an arm 28 pivoted to a slide 22 and provided with a gripping-dog 27<1>. The slide is pressed upwards against its guides by a spring - pressed plate 23, and carries the other dog 26<1> of the gripper. The dog 27<1> is raised out of contact with the strip during the rearward motion of the rod 30, and is held against a screw stop 31 on the slide. The chains are formed upside down so as to permit of bending the parts 90 upwardly and thus avoid unnecessary bending while facilitating the feed by presenting smooth surfaces in the direction of the feed, and avoiding the necessity for lifting the strip out of the lower dies. The strip is first scored by knives 41, 43 on the dies; the scores on the upper surface of the strip are parallel with straight or transversely scored forward ends and the rear ends being tapered or transversely scored, and the lower scores have parallel parts 82, 83, transverse scores 83<1> and taper or transverse scores 82<1>, the transverse scores, which may be hook-shaped as shown, serving to prevent tearing of the end bars along the lines of score and to avoid sharp corners, and the taper scores serving to provide clearance for bending the portion 90 that is to form the sprocket portion of the link. Instead of transverse scores, holes may be punched or drilled at the ends of the parallel scores. After the next feed of the strip, the metal is slit along the line 82<2> between the dies 45, 46 and the metal to form the rear end bar is bent upward on the die 46 and the metal to form the sprocket portion crimped by the die 45, the lower die having a gap 47 and a bevelled portion 48 for this purpose. After the next feed of the strip the rear end is turned by the shoulder 52<1> round the die 49 and the portion 90 is bent up into the form shown at 85, Fig. 14, by the die 52 and by the portion 51<1> and the die 51 and shoulder 52<a> on the lower die. At the same time the portion 95 of the strip is curved by the portion 51<1> of the die. After a further feed of the strip, the quarter-circle die 57 bends downwardly the portion 95 into the position shown in Fig. 14 and the part 90 is bent into substantially vertical position. The rear end bar is curved as shown at 89 between the portion 51<a> of the die 51 and the shoulder 52<b> on the lower die, a scoring-knife 53 engaging the strip between the parts 51<a>, 51<1>. The parts 51<a>, 51<1> are of quarter-circle shape, symmetrically arranged with respect to vertical lines passing through the centres of their circles so that the work is performed entirely by the upper or tower surfaces of the dies to avoid breakage and disarrangement of the die elements due to doing work on their sides. After a further feed, the strip is severed so as to detach the link by the die 57, and the rear end bar portion 93 of the link is completed by the dies 58, 59. The part 90 is bent round the rear end bar of the preceding link so as to form the sprocket portion 92 by the dies 60, 61, the die 61 having also a stop 62 to preserve a gap between the ends of the portions 92, 95. The pitch of the links which may vary due to variations in thickness of the metal is maintained uniform by a pair of fingers 78<e>, 78<a>, Fig. 5, which stretch links of smaller pitch. The finger 78<e> is carried by a lever carrying a screw stop 78<a> engaging the arm 78. The stop has a toothed head engaged by a spring-pressed pawl 78<i> for fixing in its adjusted position. The chain is extracted by a toothed wheel 70, Fig. 1, mounted in an enclosed guide 66 and rotated by a ratchetwheel and pawl from a rod 76<a> carried by the slide 5, a spring 77 bearing against the toothed wheel. The guide has a pivoted cover 68 to facilitate access to the interior of the guide. The strip, when of thick metal, before entering the dies is passed first over a centring-guide 64 with a V-groove in its upper surface so that the strip may rest at the centre of the groove slightly above and in the longitudinal plane of the lower dies. The strip is bent down by the upper die and its resiliency causes it to be raised so as to facilitate the feed when the upper die is raised. In the case of thinner metal the strip 36, Fig. 12, passes through a guide 86 V-grooved on its underside and is raised by a spring pin after the upper die recedes.