GB738648A - Improvements in or relating to automatic sewing machines - Google Patents

Abstract

738,648. Sewing-machines. CLARKE, J., and CLARKE, V. Nov. 6, 1952 [Nov. 16, 1951], No. 26858/51. Class 112. A stop-motion device in a sewing-machine comprises first guide means adapted to be engaged in one position by the thread and to be moved to another position should the thread break, a rope drive including side-by-side fast and loose pulleys, second guide means adapted to move the driving rope on to the loose pulley, means adapted to interconnect said guide means so that, should the rope break, movement of the first guide effects operation of the second and stops the drive, the device being adapted to be mounted completely on the work table of the machine and to operate independently of the mechanism of the machine. The first guide is constituted by the looped end 2 of a finger 1 which moves when the thread breaks to produce longitudinal movement of a shaft 22 having a looped end 29 constituting the second guide means for moving the driving rope 34 from a fast pulley 32 to a loose pulley 33. Finger 1 is carried at one end of a rod 3 journaled in a bracket 4 mounted on the work table 5. An arm 8 on the other end of rod 3 is connected by a linkage 9, 15 to a bar 12 pivoted at 13 to a bracket 11 mounted on the underside of the work table. The free end of bar 12 is biased downwardly by the weighted upper end of a trip member 16 pivotally mounted on a rod 17 slidable in bracket 11, said bias being partly counteracted by a weight 6 fixed eccentrically on rod 3 to minimize the thread friction on loop 2. Rod 17 is fixed at 21 to shaft 22 which is slidable in bracket 11 and is biased by a spring 23 to abut a second trip member 24 pivoted at 25 to bracket 11. On the thread breaking, the weighted end of trip member 16 moves bar 12 downwardly to raise finger 1 and to move the opposite end of said member into the path of a pin 20 carried by a continuously rotating pulley 18. Trip member 16 is thereby swung into contact with a finger 26 carried by trip member 24 and the latter is thus pivoted to permit displacement of shaft 22 through a slot in member 24 and into a hole in the end lug of bracket 11. The movement of shaft 22 is limited by a block 39 on the latter engaging an abutment 40 on bracket 11, said movement also displacing member 16 beyond the orbit of pin 20. A screwthreaded pin 38 on block 39 is connected to a handle (not shown) for restoring shaft 22 to the driving position. Finger 26 may also be tripped, to stop the drive, by a finger 41 which is pivoted in a lug 42 and carries a handle 43.