Patent GB-515902-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B15/00
Filed: 1938-06-15
Abstract: 515,902. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd., GOULDBOURN, J., and KESTELL, T. A. June 15,1938, No. 17760. [Class 112] In a curved hooked-needle chainstich weltsewing machine, such is described in Specifications 17328/08 and 13873/10, [both in Class 112], the needle, awl and channel guide are arranged to give a substantially continuous feeding movement to the work and to be always close together laterally of the machine to facilitate turning of the shoe when sewing round the toe. The needle and awl both enter the work from the side opposite to the channel guide, the awl being thicker and of larger radius than the needle, and the awl and needle feed the work alternately, the channel guide continuing the feed while both these instruments are out of the work twice in each cycle; the awl feeds the work further and faster than the needle, so that the work is given a momentum to reduce the strain on the needle. The awl enters the work in front of the channel guide, not quite completely piecing it, and carries it away to the left into line with the needle, which completes the piecing. The needle 3, Fig. 1, is carried by a rotatable and slidable member 9 oscillated by a link and cam lever, and the needle carrier carries a needle guide sleeve slidably keyed to a driving sleeve which is actuated by a toothed segment adjustably connected to another cam lever. The awl 1 is carried by a rotatable and slidable member 35 oscillated by a link and cam lever; the bearing for the member 35 is adjustable so that the plane of the awl path is parallel or at an angle to that of the needle, the arrangement in the latter case being such that the turning of the work at the toe brings the awlhole into line with the needle. Feed; channel guide.-The awl feed is derived from a cam-lever 171, Fig. 6, through links 165, 159, lever 157 and link 149 pivoted to the member 35 at 147; the links 165, 159 are guided by a link 163 pivoted at 125 to a yoke 127 which is pivoted at 129 and is adjustably clamped by the pivot bolt 125 engaging a slot in a part 133 of the frame, the feed being varied by this means. The pivot 147 has eccentric adjustment to vary the relation between awl and needle feeds. The needle feed is derived from a camlever 117 connected through similar mechanism, also making use of the yoke 127 to give simultaneous adjustment, to a lever 89 linked to a rod which engages a bore in the member 9 with play to allow slight relative tilting. The channel guide 5, Fig. 1, is fixed, with eccentric adjusting means, to a lever 177, Fig. 6, mounted on a spindle 181 which has an eccentric portion for adjustment of the guide forwards or backwards and which is connected by a scale-beam 139 and links 200 to arms on the awl- and needle-feed levers 157, 89 the channel guide thus deriving its feed movements from a combination of the movement of these levers. Welt guide; stopping gear.-The welt guide 215, Fig. 1, is carried by a lever 217 having eccentric adjustment on a slidable pivot 221 which is connected by a link 239, Fig. 6, to the lever 157 so that the welt guide moves laterally with the awl. The lever 217 has an arm 241 connected by a link, having a loosely-mounted pivot pin to allow lateral movement of the lever 217, to locking and actuating mechanism similar to that used for the pressure foot in Specification 410,463 but with the locking arm connected to its cam-lever by a ball detent allowing overrun of the lever. The guide engages the work, under the action of a spring attached to the arm 241, except when the channel guide is moving backwards, and is locked against rearward motion during most of the cycle. The machine is provided with stopping gear similar to that described in Specification 5453/12, [Class 112], the stopping arm 415 unlocking the welt-guide by a link 453 and moving it rearwardly by a lever 443 actuated through a member 435 interposed by the treadle lever 429. Stitch-forming devices.-A thread deflector 303, Fig. 1, is arranged and operated similarly to that described in Specification 480,753, the movement being modified to allow for the needle feed; the deflector may be connected to the welt guide as described in that Specification, to ensure engagement with the thread at a uniform distance from the work, but this is not necessary. The needle moves towards the work slightly during its back feed to avoid strain on the thread loop. A looper 361 and thread finger 363 co-operate similarly to those described in Specification 480,753, the thread-finger being operated by mechanism as described therein to give a threadmeasuring action. The looper 361 is secured to a lever 381 universally mounted at 385 and connected to a member 391 which is mounted on a link 395, Fig. 13, and derives longitudinal and lateral movements from a pair of cam levers 406 in a plane approximately perpendicular to the looper. The movements of the stitchforming devices are fully described.