GB759397A - Improvements in sewing machines - Google Patents

Abstract

759,397. Sewing machines. UNION SPECIAL MASCHINENFABRIK GES. Feb. 25, 1954 [March 25, 1953], No. 5544/54. Class 112. In a zig-zag sewing machine having a needle bar 12 and a looper carrier 19, both of which are displaced during stitch formation transversely to the direction of feed, the needle bar oscillating about an axis 50 parallel with the direction of feed, said transverse displacement is effected by connections from the needle bar and looper carrier to a control shaft 36, the longitudinal centre lines of which connections lie in or adjacent to a plane passing through the longitudinal centre lines of the control shaft and needle bar. As shown, the needle bar carries a pair of needles 13, and a pair of loopers 18 are correspondingly mounted in the carrier 19, the latter being pivoted on a pin 30 carried by a sleeve 31 secured to a shaft 32. The main driving shaft 5 in the base 1 of the machine is provided with a crank 7 which is connected by a pitman 10 to one end of a lever 9 pivoted at 8 in the upper arm 3 of the machine, the other end of lever 9 being connected by a link 11 to the needle bar for reciprocably driving the latter. Shaft 5 also drives the control shaft 36 through worm gearing 37. An eccentric 53 carried by shaft 36 is connected by a pitman 54 to a member 33 secured to shaft 32, whereby reciprocating motion is imparted to the latter and thereby also to the looper carrier 19. Member 33 has a forked end which embraces an eccentric 34 carried by hasft 5, whereby shaft 32 is rocked for imparting needle-avoiding movements to the loopers. An eccentric 21 carried by shaft 5 is connected by a pitman 22 to one end of a lever 26 pivoted at 25, the other end of lever 26 being connected by a link 27 to a crank 28 secured to the carrier 19, whereby the latter is rocked about pin 30 to impart loop seizing and shedding movements to the loopers. Carrier 19 is made in two parts adapted to be uncoupled by means of a button 20, to enable the loopers to be swung into a position convenient for threading. The upper end of shaft 36 carries a cam 41 which is of disc-form and which has a stepped periphery. Cam 41 is embraced by a pair of rollers 42 carried by one arm of a bell-crank lever 46, the other arm of which is formed with a slot 47a engaged by a pin 47b carried by one end of a link 48 the other end of which is pivoted to the gate 49 in which the needle bar is slidably mounted, whereby the gate is rocked about its pivot 50. The gate is provided with a stirrup 51 which co-operates with a thread guide 52 mounted on the upper end of the needle bar. The standard 2 and head 4 of the machine are provided with detachable covers 3a and 4a respectively. Lubrication. Eccentrics 21 and 34 are contained in an oil-tight chamber 56 communicating by a passage 40 with the base of the standard 2. Shaft 36 is hollow and is formed at its lower end with spiral grooves which serve to force oil up the base of the shaft, the oil spilling over the cam 41.