GB436049A - Improvements in zigzag-stitch sewing machines - Google Patents

Abstract

436,049. Sewing-machines. FAIRWEATHER, W. C., 65, Chancery Lane, London.-(Singer Manufacturing Co.; Elizabeth, New Jersey, U.S.A.) Dec. 20, 1934, No. 36512. [Class 112] In a zig-zag stitch sewing-machine, the needle gate is vibrated by a pitman which is laterally oscillated by a cam, a roller on the pitman engaging a guideway which can be angularly adjusted and bodily displaced in order to vary the amplitude of vibration and the neutral position of the needle, respectively. The needle gate 13 through which the needle bar slides, is pivoted at its upper end 14 and has a lateral projection 18 carrying a slide block 19 engaged by the forked end 20 of a lever 22 connected to a pitman 24. The pitman 24 has a forked end 25 engaging a cam 26 on a shaft 27 geared by skew-gearing from the main shaft 5 and at half the speed. A roller 30 on the pitman engages a slot 31 cut in a head 32 secured on the end of a shaft 36 which extends to the opposite side of the machine head where it is fitted with a thumb lever 47 secured by a set-screw 46, Fig. 5. The shaft 36 passes through a sleeve 37 on which is eccentrically mounted a sleeve 42. The sleeve 37 passes through slots 41 in a guide member 38 and the eccentric sleeve 42 engages surfaces 44<1> on the member 38. The slots 41 are parallel to that position of the guide 31 which ensures the maximum longitudinal travel of the pitman 24. The sleeve 37 has a handle 45 by turning which the sleeve can be moved from one end of the slots 41 to the other thereby moving the guide 31 from a position in which the roller 30 makes equal excursions on opposite side of the centre of the shaft 36 to a position in which the roller reaches the centre of the shaft only at one end of its travel. By extending the slots 41 an equal adjustment in the opposite direction may be made. A member 52 secured to the guide 38 by screws carries two scales 70, 71 co-operating with two pointers 75, 76 on a member 74 secured to the thumb lever 47 by a screw 73. Movement of the handle 45 causes one or other of the pointers to be covered up by its scale in its two extreme positions of adjustment. Adjustable stops 57, 58 on a plate 48, which has a lug 50 engaging slots 53, 54 in the member 52 and guide 38, limit the movement of the lever 47. The guide 31 has a curvature which is centred at the end of the pitman when the lever 47 is in its lower position, the pitman then vibrating idly without moving the needle gate. A notched spring wire 62 secured to the plate 48 by a screw 61 yieldingly engages a pin on the lever 47, and a spring washer 66 between the head 32 and the guide member 38 assists in keeping the shaft 36 in any angularly adjusted position. Specification 416,619 is referred to.