GB793591A - Improvements in or relating to sewing machines - Google Patents

Abstract

793,591. Sewing machines. UNION SPECIAL MACHINE CO. June 12, 1956 [June 14, 1955], No. 18046/56. Class 112 Lock stitching by rotary hooks, multineedle machines. In a vertical axis rotary hook provided with a loop-seizing beak 19, the top portion 31 of the outer surface of the latter is inclined towards the axis of the hook, and a pin 39 extends outwardly from said inclined surface adjacent the base of the beak, the forward side of the pin engaging the needle thread loop 53 to carry the upper leg thereof across the top of the bobbin case 21. The lower portion 34 of the outer surface of the beak is also inclined towards the axis of the hook. A shoulder 43, formed between surface 34 and the outer cylindrical surface of the hook and located in vertical alignment with the pin, retains the lower leg of the needle thread loop for carrying the latter leg across the bottom of the bobbin case. A pair of hooks are incorporated in machine having a pair of needles 10, the hooks being disposed on opposite sides of a throat plate 23 formed with a pair of slots 54 for the feed dog 13. A projection 22 from each bobbin case lies within a gap 23b formed in a respective rib 23a projecting downwardly from the throat plate. In operation, projection 22 abuts one end of gap 23b. A finger 24 carried by a rock-shaft 27 is adapted to co-operate with a projection 25 on the bobbin case to shift the latter slightly when the upper leg of the loop 53 is in vertical alignment with gap 23b, whereby said leg may be drawn upwardly between projection 22 and the end of gap 23b previously abutted thereby. A gear 16 on a hook-carrying shaft 15 meshes with a gear 16a on a driving shaft 16b, and an eccentric 30 on shaft 15 is connected by a pitman 29 to a crank 28 on shaft 27. Needle guides. An annular plate 44 is secured to the lower surface of the hook body 18 by means of a pair of screws 45 and 46, the latter of which passes through a slot 47 in the plate. Upstanding from plate 44 is a needle guide 20 the curvature of which is such that its mid-portion extends radially outward slightly more than either end portion. Plate 44 may be angularly adjusted about the leading screw 44, in order to ensure the desired outward deflection of needles, of varying thickness, in advance of the loop-seizing beak. Work supports. The inner and outer edges of the feed dog receiving openings 54 in the throat plate 23 are bevelled as at 55a and 56 respectively. It is stated that this serves to minimize the accumulation of lint in the groove at the top of the feed dog. U.S.A. Specification 2,329,484 is referred to.