Patent GB-191214661-A (GB)
Title: Improvements relating to Sewing Machines.
IPC: D05B57/02
Filed: 1912-06-22
Granted: 1913-08-22
Abstract: 14,661. Baker Sewing Machines Trust, and Baker, F. June 22. Sewing-machines; loop-stitching; chain-stitching; lock-stitching by hooks.-Relates to machines of the kind having a rotary loop-taker which releases the thread-loops before having carried them half a revolution and so as to cause them to slip over a stationary loopcontrolling device. Forms of the apparatus are described which make the locked loop-stitch described in Specification 18,052/07 and in these the long loops, Fig. 11, are held while the short loops are threaded over them, by the hooks formed in rotary disks d. By suitably proportioning the parts, the needle may be caused to descend through the long loop at each stitch so that the short loops go through and then around the long loops. Fig. 1 shows a construction in which the controlling-device D is arranged upon the periphery of the loop-taking disk B. Each thread loop is engaged by the loop-taking point b<1> and carried to the position shown. Shortly afterwards, a bridle - piece, through which the point b<1> projects, and which is carried by a lever b<2Î>, is caused to turn outwards by the action of a cam on a cam-bowl b<3> and strips the thread loop from the point. The part b<2Î> that carries the bridle-piece can turn about its longitudinal axis within the shank-part b<2> of the lever, and such a movement is imparted to it as the lever swings outwards by a cam-piece b<5Î> which engages a bowl b<3Î>. This turning movement of the bridle-piece causes the thread loop to pass on to the thin tail D' of the controlling-device. If one of the hooks d<4>, Fig. 4, of the disk d is positioned as shown, it catches and retains a thread loop as the loop slips over the device D. The pull of the thread loop upon the disk then turns the disk sufficiently to mask the hook behind the part d<2>, and thereafter subsequent loops slip over the one so retained and are drawn up into the work until the disk has been urged round into a position to release the loop. In that position, another hook is ready to catch a thread loop, and the cycle is repeated. Fig. 7 shows an escapement for controlling the movement of the disk d. After the catching of a thread loop by a hook d<4>, the disk is released by the depression of the detent d<10>, Fig. 7, and is turned until a wedge-shaped projection d<7> abuts against a spring-pressed brake d<8>. Succeeding stitchtightening operations move the disk round from one projection d' to the next until the hook d<4> releases its loop. The controlling- device D, Fig. 1, is held alternately by two retainers E, E<2>, which are suitably connected together and actuated by means of the shaft E'. Figs. 11 and 13 show a construction in which the controlling-device D is arranged at the side of the loop-taking disk. It is supported by two ribs B<1>, B<2> on the disk and is held from rotation with the disk by a disk engaging with a transverse groove in it. This disk is positively oscillated and has a notch which receives the thread loop as it slips over the device and carries it through the groove with which the disk engages. The oscillation is effected by a segmental gear F<2> and a camactuated slide G'. A gap is cut in the rib B<1> and the rear wall of this gap forms the looptaking point. The controlling-device is further supported and periodically slightly moved, to make free the passage of the loop, by a camactuated lever H. The thread loop is presented centrally to the needle, which passes to one side of the disk d, by causing one arm of the loop to pass round a finger J, Fig. 11. This finger is shown integral with the device D, but it may be pivoted upon it and urged by a spring into a position a little to the right of that shown. The rotation of the loop-retaining disk is controlled by a cam - operated lever - plate d<12>, Fig. 20. In place of the transversely-arranged disk for holding the controlling-device, a disk L, Fig. 28, may be used, having an annular rib l<x> projecting from its face into a corresponding groove. This rib has a notch in it which engages the thread loop and carries it through the groove. For the operation of the shaft of the disk L the pitman L<3>, Fig. 31, which operates the main shaft is formed with a branch L<7> engaging a disk L<9> on the disk shaft. Fig. 35 shows a construction in which the device D is held alternately by two cam-controlled rods N. M. Feed by dog.-The feed-dog K<3>, Fig. 35, is supported upon a cam which gives it a vertical reciprocation and is held by a spring in constant engagement with a rod O. The rod O is pivoted at one end and contacts with a camlever O<2>, and thereby imparts a feed-movement to the dog.