GB576765A - Sewing machine - Google Patents

Abstract

576,765. Sewing-machines. SINGER MANUFACTURING CO. May 17,1944, No. 9420. Convention date, May 28, 1943. [Class 112] [Also in Group XXIV] Starting and stopping. In order to allow of the mechanism being brought to a predetermined position of rest at the end of its operation when desired, without subjecting it to the shock of a positive stop from high speed every time it is stopped, means are provided whereby, after the machine has been stopped in an indeterminate position, the operator can initiate a supplementary motion which is stopped positively when the parts are in the required position. In the arrangement described, the motive power for the supplementary movement is provided by a spring which is stressed during starting of the machine. and is held stressed until released by the operator. The machine is driven by a belt from a pulley which forms one element of a friction clutch on the shaft of an electric motor; the clutch is engaged by a spring-biased treadleoperated lever which carries a brake shoe to engage the pulley when the clutch is disengaged. The driving pulley 51 is free on the hub of a disc 53 fixed to the main shaft of the machine, and is connected to the disc by a spiral spring 58 arranged in a recess in the pulley and adjustably attached thereto by its end engaging one of a series of notches in the periphery of the recess; a stop 62 on the disc is engaged by a similar stop on the pulley to limit the unwinding of the spring. When the motor is started the spring is stressed until the machine is running at the same speed as the pulley, and is then held stressed by a spring latch on the disc 53 engaging a toothed flange 64 on the pulley 51; overstressing of the spring is prevented by the stop on the pulley engaging the other side of the stop 62. The latch is releasable by a ring 69 carried by a pivoted arm 70 which is pressed to the right against a spring by a cam lever 77 actuated through a linkage 34, 33, 79 by a kneeoperated lever (not shown), which also lifts the presser-bar; release of the latch allows the spring 58 to rotate the mechanism (the pulley 51 being held by the brake of the driving-gear) until a stop 81 on the disc 53 engages a shoulder on the arm 70. Presser-bars, lifting. The presser-bar is lifted by a lever 32 actuated through a lever 34 and link 33 by a knee-actuated lever (not shown).