GB948129A - Improvements in or relating to sewing machines - Google Patents

Abstract

948,129. Sewing machines. FILOTECNICA SALMOIRAGHI S.p.A. April 6, 1960 [April 7, 1959], No. 12147/60. Heading D1G. In a sewing machine a single manuallyoperable knob is adapted to control the stitch length both when the feed is under automatic control by a cam disc and also when the cam control is inoperative, and a control lever is adapted to reverse the feed when the latter is either under automatic control or not. A rotary feed-control cam 3 co-operates with a follower 5 pivoted at 6. A cam 9 pivoted at 10 co-operates with a finger 7 rigid with follower 5 to disengage the latter from cam 3. A finger 8 rigid with follower 5 abuts an arm 11 pivoted at 12 to one arm 15 of a bell crank. lever 15, 20 pivoted at 16. A spring 27 acts on arm 15 to bias a roller 21, carried by arm 20, against the inner edge 22 of a cam slot formed in a rotatable disc 24. A vertically-slidable spindle 30 is coupled at its lower end by rack and pinion gearing 33 to the feed advance shaft 34. A torsion spring 35 acts on the latter to engage the upper end of spindle 30 with a lug 13 on arm 11 for maintaining arm 11 in contact with finger 8. When follower 5 is disengaged from cam 3 and disc 24 is rotated clockwise by a graduated control knob, lever 15, 20 pivots counterclockwise as roller 21 follows edge 22, whereby arm 11 rocks about finger 8 to vary the position of lug 13 for increasing the stitch length. At any setting of said knob, an arm 40 rigid with lever 15, 20 may be shifted to transfer roller 21 to the outer edge 23 of the cam slot for producing reverse stitching of the same magnitude. Oscillation of follower 5, when engaged with cam 3, is transmitted via finger 8, arm 11 and spindle 30 to shaft 34 for varying the stitch length. The magnitude and direction of the automatically-controlled stitch length may be modified by manipulation of the control knob and arm 40.