GB957497A - Regulating mechanism for a sewing machine - Google Patents

Abstract

957,497. Sewing machines. MEFINA S. A. Feb. 27; 1963 [March 7, 1962],No. 7818/63. Heading D1G. In a sewing machine a control knob is fixed to a rotary shaft carrying a cam, part of the profile of which co-operates with a first follower adapted to actuate a lever for varying the angular position of a feed-control shaft, the feed being thereby manually controllable, and another part of the profile of which co-operates with a second follower carried at one end of a support lever, whereby a follower carried at one end of a return lever, pivoted to the support lever, is engaged with a rotary cam, the other end of the return lever being pivoted to a slide carried by the feed-control shaft, the feed thereby being automatically controlled, and the part of the cam profile acting on said second follower being so inclined as to permit of adjustment of the angular position of the knob corresponding to automatic control. A feed-control shaft 1 is biased by a spring to urge a follow 10, carried by a lever 3 pivoted on shaft 1, towards cam 14 on a shaft 15 rotatable by means of a control knob 16. A spring 6, having one end engaged with a pin 8 projecting radially from shaft 1 and the other end engaged with lever 3, also biases follower 10 towards cam 14. The profile of the latter has four sections I, II, III and IV. Section I controls the reverse feed from stitch lengths zero to minus 4. Section II controls the forward feed from stitch lengths zero to plus 1. Section III controls the forward feed from stitch lengths plus 1 to plus 4. A support lever 25, pivoted at one end at 27 to the machine frame 2, is biased by a spring 43 to engage a follower 29, carried at the other end of lever 25, with cam 14. A return lever 20 carries at one end a follower 19, is pivoted intermediately at 24 to lever 25, and is pivoted at its other end at 21 to a block 22 slidable in a guideway 23 carried by shaft 1. The arrangement is such that when follower 29 engages Section IV of cam 14, follower 10 is disengaged from the latter and follower 19 is engaged with a rotating cam 18 to effect automatic control of the feed. Section IV is inclined in order to accommodate variations in the profile of cam 18. A lever 34, pivoted at 35 to the machine frame, carries a lug 37 engaged with pin 6, whereby, when lever 34 is turned by pressure on a lug 33 thereon during forward stitching, shaft 1 is rotated till a lug 39 to lever 34 engages a cam 41 on shaft 15 to establish reverse feed of the same magnitude as the forward feed. When follower 29 engages section IV of cam 14 for automatically-controlled feed, a portion of cam 41 engages lug 39 to shift lug 37 clear of pin 8. Specifications 683,370 and 683,380 are referred to.