GB637976A - Clamp raising and lowering means for sewing machines - Google Patents

Abstract

637,976. Sewing-machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.). June, 16 1948 No. 16203. [Class 112] Starting and stopping; button-attaching machines. A machine with a work-clamp, a laterally-vibrating reciprocatory needle-bar, and stopgear to bring it to rest at the end of a predetermined cycle has a member mounted for vertical reciprocation in a fixed path at each reciprocation of the needle-bar and means actuated in timed relation to the stop-gear to couple the work-clamp to the member for automatic lifting of the clamp as the machine comes to rest. The clamp is lowered as the machine starts the next sewing cycle ; the coupling means may be put out of action by a hand control. In the machine shown, for attaching flat buttons, the pivoted work-clamp 41 has a fork 42 embracing a stud carried by a spring-depressed vertically-slidable bar 46, which can be lifted by a treadle-actuated lever 51 ; the bar 46 also carries an arm 54 clamped to the lower end of a bar 26 which is vertically slidable in the machine head. The needle-bar reciprocates in a sleeve 23 on an arm 22 mounted on a pivot 19 and oscillated in the usual way to shift the needle-bar laterally between strokes ; a member 27 slidable on the bar 26 and vertically reciprocated by a link 33 from a crank on the main shaft 6 has a fork engaging a collar 29 on the needlebar so as to impart the vertical movements to the latter. The shaft 6 is driven from a stub-shaft 9 carrying the usual stop-gear 12 brought into operation, to stop the machine with the needle raised, by a latch 16 actuated by lugs 17 on the control cam 18 : the shaft 9 revolves at half the speed of the shaft 6 to lessen the shock of stopping. Lugs 65 on the cam, suitably placed relatively to the lugs 17, engage a lever 64 connected to a rod 59 which engages a latch member 58 pivoted at its lower end to the bar 26 and formed with a part adapted to engage over a shoulder on the member 27 ; the rod 59 is spring- pressed to the right-hand position shown, in which the latch 58 is disengaged, and is moved to the engaging position during the last needle stroke before stopping so that as the needle rises to its final position the clamp is lifted. Automatic lifting may be prevented if desired by pushing the rod 59 further to the left, bringing the lever 64 clear of the cam and the latch 58 clear to the left of the member 27, by means of a knob 66, on the rod, which has means for locking it in the left-hand position. Frames. The work arm 1a is of inverted U-section, with a removable sheet metal cover 1b with a spring- pressed hinged end 1c. Specifications 476,764, 545,034 and 624,834 are referred to.