GB360231A - Zigzag-stitch sewing machines - Google Patents

Abstract

360,231. Sewing-machines. SINGER MANUFACTURING CO., Elizabeth, New Jersey, U.S.A. Dec. 4, 1930, No. 36564. Convention date, Sept. 23. [Class 112.] The means for automatically varying the amplitude of lateral vibration of a needle bar and the means for changing from one to the other of the stitch groups shown in Fig. 9 are so arranged that a zero setting of the amplitude adjusting device remains unaffected by a change of the vibration axis. The invention is illustrated as applied to a laterally vibrating lock-stitch rotary hook embroidering machine, described in Specification 324,613. The needle 23 is carried on a needle-bar 15 which reciprocates in bearings 16, 17 of a swing- ing frame 18 pivoted on a pin 19 with an eccentric reduced portion 20. The needle-bar is reciprocated by the main shaft 8 through the linkage 11 .. 14 in the usual way. The frame 18 is vibrated by the rock shaft 37, a cranked part 36 of which engages the frame at 35. The shaft 37 is rocked by a triangular cam 46 secured to the gear 47 through the linkage 44, 42, 41, 40. The pitman 44 has a bifurcated end 45 embracing the cam 46 and has a bifurcated link 52 secured to it by a pin 50. The link 52 is pivoted at 53 to a crank arm 54 of a crank shaft 55 journalled in an eccentric bushing 56. The amplitude of needle vibration is adjusted by an arm 77 fixed to the end of the shaft 55. The movement of the arm is limited by stops 81, 82 or intermediately by stops 73, 74 on a segmental plate 71. To give a stitch group symmetrically disposed about its axis as S<1>, Fig. 9, instead of one with one straight edge as S, an arm 62 attached. to the bushing 56 is swung from the position. shown in Figs. 1 and 4 to a position where a latch. pin 63 enters a socket 70. This bodily displaces the shaft 55 about the axis of the bushing 56 and the pivot 53 on the crank 54 moves normally to an imaginary line between the cam axis and the pivot of the pitman 44 on the link 42. While the pivot 53 lies on this line, the shaft 37 will not be rocked and the needle will reciprocate without vibrating. The pivot 53 is brought back to this line by a stop screw 84 on the arm 62 engaging the controlling arm 77. The shaft 55 is thereby rocked to bring back the pivot 53 into the imaginary line. This adjustment moves the mean position of the needle reciprocation axis out of the vertical and it is brought back to the vertical by turning the pivot 19 of the frame 18 about its eccentric extension 20. A scale is fitted to facilitate the setting. Specifications 8706/13 and 324,613, [both in Class 112, Sewing &c.], are referred to.