GB240776A - Sewing machine needle controlling mechanism - Google Patents

Abstract

240,776. Fairweather, W., (Singer Manufacturing Co.). July 24, 1923. Sewing-machines; needle-driving mechanism, disconnecting and controlling; multiple-needle machines. - A machine having means for temporarily throwing out of action one of a number of needles is provided with a device for automatically recoupling the needles after a predetermined number of stitches. The mechanism is of the kind described in Specification 228,085, and comprises an auxiliary needle-bar 13 which is coupled to a primary needle-bar 9 by a pin 26 sliding in a lug 25 to enter an aperture in the bar 9. The pin extends from a block 29 sliding on a vertical pin 30 which is mounted on a slide-block 31. The slide-block is pivoted to a rocking arm 37 connected by a link 39 to a lever 40 stressed by a spring 42 in a direction to hold the pin 26 in coupling position. The lever 40 is connected by a link 45 to a manuallyactuated lever 46. Uncoupling of the two bars except at the top of a stroke is prevented by a stop member 51. The needle-bar 13 is retained in disconnected position by a catch 53 until recoupled by mechanism described below. A spring- stressed buffer-rod 56 limits the upstroke of the disconnected needle-bar. The lever 40 is retained in position to keep the needle-bar disconnected by a spring latch 61 which engages a stud 59 on the lever. The latch is moved to release the stud after a predetermined number of stitches by a tappet 68 mounted on a shaft 70 which rotates within a sleeve 71 journaled in a bushing. An indicator disc 75 is fixed to the sleeve 71 and beyond the disc is a tappet-adjusting head 79 which may be locked at different positions to the disc by moving it endwise against the action of a spring and rotating it to vary the position of a locking-pin. An arm 85 mounted on the bushing 72 and continuously oscillated by a pitman 88 and eccentric 91 and carries a pawl 93 adapted to engage the teeth 95 on a ratchet wheel 96 stressed by a coil spring 98 so that a stop 102 thereon engages an adjustable stop 103 on the framing. A stop pawl 108 prevents retrograde movement of the ratchet wheel during actuation by the pawl 93. When the needle-bars are coupled together, both pawls are held away from the wheel 96 by the engagement with a shoulder 110 on the pawl 108 of a stud 111 on the arm 40. In operation, the number of single-needle stitches to be made at a corner is determined by moving the graduated disc 75 to the desired index mark which causes the adjustment of the releasing tappet 68. When the disconnection of the needle is manually effected at the approach to a corner the pawls 93, 108 are allowed to engage the wheel 96 owing to the movement of the retaining stud 111 and the wheel 96 is then advanced step by step until the tappet 68 comes into operation to put the disconnecting mechanism out of action.