GB1343260A - Sewing machine - Google Patents

Abstract

1343260 Sewing machines MEFINA SA 12 April 1972 [20 April 1971] 16787/72 Heading D1G A zig zag sewing machine has a stack of cams 8 and other cams 21, 42, 71 for (a) simple or buttonhole sewing, (b) automatic control of zig-zag sewing (c) simultaneous control of stitch width, needle centring and feed direction, and (d) regulation of stitch length and direction of feed by actuation of the control knobs 44, 45, 52, 56. A lever 9 pivoted at 11 transfers the motion of a cam follower 10 to an intermediate member 12 the other end of which 17 presses against a ramp surface on a disc 18 attached to the end of a sliding rod 14. The rod 14 causes the needle bar to swing about an axis parallel to itself. A second cam follower 38 is connected through links and levers 32, 33, 34, 37 to a vertical shaft 31 (Fig. 4) which controls the movements of the feed dog. Certain of the cams in the stack 8 are provided for this control. A knob 56 is provided to temporarily disengage both cam followers while choosing new cams by rotating cam selection knob 45. The knob 52 through the cam 21 simultaneously controls stitch width, needle centering and feed direction. To alter the needle centering the ramp surface on the disc 18 is moved so that the nose 17 presses against a different part of it. To compensate for manufacturing tolerances in the cam surfaces knob 44 has a cam 42 against which engages a follower 41 on an eccentric axis 39. Manual control of the feed dog is possible by actuating the knob 44 when the feed dog is not being automatically controlled, i.e. when the second cam follower 38 is not being driven by a cam.