GB189680A - Thread controller - Google Patents

Abstract

189,680. Fairweather, W., (Singer Manufacturing Co.). Jan. 11, 1922. Multiple-needle machines; chain-stitching.- A take-up for the control of the under-thread comprises an oscillating arm having a concave thread-engaging edge at one side ending in a thread-engaging projection from which a threadengaging surface extends to a convex cam edge on the other side, the arm coacting with fixed cast-off arms effecting differential thread control on oscillation of the shaft. A rock-shaft 10 mounted in the work-shaft 5 is oscillated by an eccentric strap 14 and arms 12, 13. A cam-arm 17, slotted to receive a cast-off arm 37, 39, 40, is mounted on the shaft 10 and is formed with a forward cam edge 20, a flat curve 19 and a rear convex edge 21. Arms 30 provided with guide eyes 32 extend on each side of the arm 17 and are carried by a plate 28 pivoted at 29 and having a tail-piece engaged by a spring 34 by which it is retained in lowered or raised position. A cast-off arm 37 secured on the plate 28 extends into the slot of the arm 17 and comprises a sharply inclined part 39 and a practically horizontal part 40. A slotted pull-off arm 42 having a cam surface 45 is arranged, similarly to the arm 17, between arms having thread eyes and embraces a take-up arm 54 on which is a projection 54<11>. A thread-nipper comprising a spring 59 engaging a block 58 is arranged between the take-up and pull-off and is opened, when the arms 17, 42 are in either of their extreme positions, by cam-projections 61 engaging the spring. A considerable amount of take-up is necessary during the retracting movement of the looper,. which takes place as the arm 17 moves to the left frcm the position shown in Fig. 5, and this is effected by the concavity of the arm whereby the horizontal part 40 of the cast-off is not effective until the arm has advanced a considerable distance. The arrangement is described as applied to a multiple-needle machine.