Skip-Stitch Mechanism for Household Sewing Machines.

摘要

1,177,469. Sewing machines. SINGER CO. 30 Sept., 1968 [6 Oct., 1967], No. 46355/68. Heading D1G. A sewing machine comprises an arm shaft, a driving member coupled to the arm shaft, a rotary driven member operatively connected to the needle bar for imparting endwise reciprocation thereto, means for coupling and uncoupling the driving and driven members under the control of programme means, and means for rendering the programme means inoperative. Needle bar 20 is mounted in a pivoted gate 22 oscillated, for producing zig zag stitching, via a pitman 70 as described in Specification 891317 from a pattern cam 38 fast with a rotary shaft 28 driven via gearing 34, 36 from the arm shaft 16. The latter is journalled at the machine head 14 in a sleeve 92 which in turn is journalled in a fixed bearing 94. Sleeve 92 is connected by a crank 24 and pitman 26 to needle bar 20 for imparting endwise reciprocation thereto. A spool-shaped driving member 112, slidably but non-rotatably mounted on shaft 16, is adapted to be moved axially on shaft 16 for being coupled to and uncoupled from sleeve 92. A compression spring 104, mounted within sleeve 92, biases the latter against a circlip 100 on shaft 16, and biases member 112 against a lower arm 180 rigid with a vertical pivoted pin 176 to engage an upper follower arm 182 with a skip-stitch control cam 188 rigid with rotary shaft 28. The arrangement is such that when arm 182 engages a lobe on cam 188, member 112 is shifted leftwards for drivingly engaging a lug 170 thereon with a lug 130 on sleeve 92, and member 112 also co-acts with a pin 160 carried by a member 132, pivoted on a pin 140, to turn member 132 clockwise against the bias of a spring 154 to disengage a lug 150, carried by member 132, from a recess (128) formed in sleeve 92. When arm 182 engages a trough in cam 188, member 112 moves rightwards to uncouple from sleeve 92, while lug 150 moves over a helical surface 124 on sleeve 92 before reentering recess (128) to hold needle bar 20 in the raised position. A pin 202, carried by arm 182, passes through a slot 196 at one end of a bar 194, the other end of which is pivoted at 208 to one end of an arm 206 pivoted at its other end on a fixed pin 210. A spring handle 214, rigid with arm 206, passes through a slot in the machine frame and is selectively engageable with notches A, B, C formed therein. When the middle notch B is engaged, pin 202 moves freely in slot 196 and the needle bar drive is controlled by cam 188. When the left hand notch A is engaged, the right hand end of slot 196 co-acts with pin 202 for coupling member 112 with sleeve 92. When the right hand notch C is engaged, a bar 216, connecting bar 206 with a bearing 218 journalling a bobbin-winding spindle 222, shifts bearing 218 rightwards for drivingly engaging a wheel 220 on spindle 222 with the main driving pulley 19.