GB291106A - Improvements in and relating to sewing machines - Google Patents

Abstract

291,106. British Thomson-Houston Co., Ltd., (Assignees of Stephenson, H. M.). May 27, 1927, [Convention date]. Driving; s p o o l s, winding. - An electric motor 7 is pivotally mounted at 12 on the underside of the workplate and has a sliding connection at 13. It is spring - pressed by means of a pivoted fork 14 to hold its friction pulley 10 in driving contact with a pulley 11 loose on the under shaft 9. The pulley 11 is normally clutched to the shaft 9 by dog-teeth on it and on the end of a worm 18 which is splined on the shaft 9 and drives the upper shaft of the machine through a worm wheel 20. The force exerted in this drive maintains the dog-teeth in engagement. If, when the motor is not running, the fly-wheel is moved by hand in the forward direction the wheel 20 moves the worm 18 away from the pulley 11 and disconnects the motor drive from the sewing-shafts. At the same time, a coned end 40 of the worm moves a lever 38, Fig. 5, outwards against a spring 14 until the lever rests on the worm thereby bringing a. friction pulley 36 into contact with the pulley 11. When the motor is started again the spool-winder shaft 34 is rotated alone. The parts are returned to their normal position by a manual movement of the fly-wheel in the reverse direction. Feed by dogs. - A cam on the vertical gear shaft 19 is embraced bv the end of a bar 26 slidingly pivoted upon a plate 27. The free end of the bar engages an inclined surface on the part 28 so that lengthwise movements of the bar 26 give a rising and falling movement to the feed-bar 29 whilst lateral oscillations of the bar 26 give lengthwise movements to the feed-bar. The length of feed is varied by movement of the plate 27 which carries the pivot of the bar 26.