GB837806A - Improvements in and relating to sewing machines, especially lockstitch sewing machines - Google Patents

Abstract

837,806. Sewing machines. UNION SPECIAL MACHINE CO. July 12, 1956 [July 15, 1955], No. 21533/56. Class 112. A lock stitch machine, Fig. 1, is provided with interconnected drive shafts 14, 46, arranged longitudinally of the arm and the base, a needle-bar 20 which swings in the line of feed for imparting feed movement to the work, a rotary hook mounted on a vertical axis, and a continuously rotated feed wheel 105 mounted on a horizontal axis adjacent the hook. Feeding work by needles. The needlebar is mounted for reciprocation in a frame 22 mounted on a pivot 24 and carrying a pin 25 connected by a link 26 to an arm 27 on a hollow shaft 28 journalled in bearings 29, 30 and carrying the bearing bushes for the shaft 14. A bracket arm 31 secured on the shaft 28 has a bearing member 31a, Fig. 10, pivoted to its lower end. A pin 32 slidingly mounted in the bearing member 31a and a bore in the strap 33 of an eccentric 34 on the driving shaft 14 carries a block 35 pivoted at 36 to a block 37 on a vertically adjustable rod 38. The eccentric rocks the bracket 31 to swing the needle-bar and the position of pivot 36 may be raised or lowered to vary the amplitude of the feeding movement by raising or lowering the rod 38 by means of the adjusting screw 39. Feeding work by wheels. The feed wheel 105, Fig. 1, is mounted on a shaft 100 carried by a bracket 102 mounted for vertical adjustment in a frame 70 mounted by means of a split extension on a bearing sleeve 72 of the driving shaft 46 so that it may be adjusted angularly and longitudinally thereof. Vertical shafts 80, 86 mounted in the frame and bracket carry worm wheel 83, which meshes with a worm on shaft 46, intermeshing pinions 108, 112, and bevel gear 98 which meshes with bevel gear 99 on the feed wheel shaft 100. The intermeshing pinions may be exchanged for a pair having a different velocity ratio to vary the rate of feed. In a modified feed wheel unit, Figs. 14-16 (not shown), the intermeshing pinions are enclosed by a cover making an oil-tight joint with the frame 70. Rotary hooks. A unit 51 which carries the rotary hook has a split collar portion 52 by means of which it is mounted on a bearing sleeve 49 of the driving shaft 46 so that it may be adjusted angularly and longitudinally thereof. The hook is driven by a spiral gear 56 on shaft 46 intermeshing with a spiral gear on the hook shaft. An eccentric on the latter shaft operates a finger to co-operate with a projection on the bobbin case to shift this slightly at the appropriate time, counted to the direction in which it is urged by friction. Presser wheels. The presser wheel 117, Fig. 11, is mounted on an arm 118 fitting in a channel in a block 119 and attached thereto by a screw 120. The block is pivotally mounted on the lower end of the presser bar 121 and is held against axial movement therealong by a block 122 rigidly secured to the bar by a screw 122a. Specification 743,637 and U.S.A. Specifications 2,329,484 and 2,609,770 are referred to.