GB894100A - Improvements in or relating to sewing machines - Google Patents

Abstract

894,100. Sewing machines. NECCHI S.p.A. Dec. 29, 1960 [Feb. 4, 1960], No. 44593/60. Class 112. In a zig-zag sewing machine, the stitch form is automatically governed by means adapted to be driven either continuously or intermittently. As shown, the machine is a modification of the one described in Specification 774,294. A vertical shaft 8, driven by the arm shaft 4, carries a cam 9 adapted to oscillate an arm 12 pivoted at 13 to an arm 14 pivoted at 16 to the frame. A link 23 carries at one end a block 22 slidably engaged with arm 12 and is pivoted at 26 to an arm 27 pivoted at 28 to the frame. A bell crank lever 33, pivoted at 35 to the frame, has one arm connected to block 22 and carries on its other arm a pin 34. A bell crank lever 36, also pivoted at 35, is provided on one arm with an abutment 37 biased against lever 33 by a spring 40, and at its other arm a handle 38 manipulation of which serves to shift block 22 for varying the stitch width. Arm 14 carries a pin 15 biased by a spring 19 against a lever 17 which is pivoted at 16 and is provided with a handle, manipulation of which serves to shift the angular position of pivot 13 for varying the mean position of the stitches. Pins 15 and 34 are embraced by the respective forked lower ends of bars 43 and 44 which are journalled at their upper ends in a fixed plate 49 and are adapted to be pivoted therein by respective cam followers 57 and 58 for automatically governing the stitch width and mean position. A cam follower 60 automatically governs the feed. The followers co-operate with alternative sets of rotating cams which may be driven either continuously or intermittently. As shown, a set of cams 78 is journalled on a fixed sleeve 49<SP>1</SP> and is coupled by a pin 83 to a gear 66 driven continuously via an intermediate shaft 64 from shaft 8. An alternative set of cones is also journalled on sleeve 49<SP>1</SP> and is coupled to the rectangular upper end 81 of a shaft 67 journalled in sleeve 49<SP>1</SP>. Shaft 67 is driven step-by-step from shaft 4 via a cam 71, follower 70 and unidirectional coupling 69. The length of step can be varied by a cam 72<SP>1</SP> coupled to a handle 72.