Patent GB-392947-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B57/14
Filed: 1931-09-29
Abstract: 392,947. Sewing-machines. BRITISH UNITED SHOE MACHINERY CO., Ltd., GOULDBOURN, J., and KESTELL, T. A., Union Works, Belgrave Road, Leicester. Sept. 29, 1931, No. 27063. [Class 112.] The loop-taking beak on a rotary shuttle case of a curved hooked needle lockstitch sewing-machine is formed with a chisel tip of such a width as to engage the greater part of the length of needle thread between the loop spreading means and the needle hook, and widens in a direction away from the tip. By this means a shorter beak may be employed, thus saving time in passing the loop over the shuttle case and giving more time in the cycle to the other operations, thus speeding up the machine. In one form, shown in Figs. 1, 2, and 3, the shuttle case 1 is in two parts 2, 3 which, when secured together, form an undercut guideway 4 for a flange 5 on a plate 6 secured to a bracket 7 on the machine frame. Each part 2, 3 has formed on it part of a wide loop-taking beak 8, 8, the tip of which is inclined substantially parallel to that portion of the needle thread 11 which extends from the hook of needle 12 to thread lifter 13 and the greater part of which is engaged when the loop is taken from the needle. The needle loop is assisted into the root 210 of the beak by the rounded end 116 of the plate 6. The casing 1 is driven by a crank 20 on a driven shaft 23 through gears 15, 16 to make two revolutions in each cycle of the machine, and the crank 20 and shafts 17, 23 are so arranged that the case 1 is faster when the loop of needle thread passes over it. The subsequent slowing down of the case 1 results in its overrunning the driving member 13 to leave a gap between the end 25 of the driving member 13 and the face 26 of case 1, through which the needle loop may pass freely as it is pulled down by the take-up. Thread from a bobbin 32, Fig. 4, mounted on an axial stem 31 in a circular recess eccentric to a bobbin case 30, passes through a hole in the side of the case 30 along a groove in which is mounted a sliding tension block 35, and through a hole 41 in the front wall of the case 30. The case 30 is rotatably carried on a pin 44, Fig. 1, in a recess 43, Fig. 3, in the shuttle casing, the axis of recess 43 and pin 44 being slightly offset from the axis of casing 1. A projection 45 on the case 30 engages in one side or the other of a recess 46 in an arm 47, which may be pivoted away from the case to facilitate removal of the bobbin, to prevent its rotary movement. A clip 51 on the arm 47 holds the loose end of the shuttle thread for the first few stitches on restarting sewing. In a modified form shown in Figs. 7, 10, 14, the shuttle casing 60 is constructed, arranged and driven similarly to that already described. Thread passes from a bobbin in a case 80, Fig. 14, through a hole 82 round a corner 83 under a ledge 84 and along a groove 85 to a hole 86 in a nose 87 which delivers it beyond the path of movement of the beak 67, 67 of the shuttle as close as convenient to the work. A slide 106 in the groove 85 tensions the thread. Rotary movement of the bobbin case 80 is preventedby a V-shaped ridge 89 on a member 90 which enters a groove in its front wall. This member 90 is mounted so as to be swung aside by a hand lever to afford access to the bobbin. A guard 110 is fixed to the member 90 to guide the loop of needle thread down to prevent its being caught on any projecting portions of the work. Specifications 23478/10, [Class 112, Sewing &c.], 357,596 and 390,842 are referred to.