GB1314988A - Control system for a lock stitch sewing machine - Google Patents

Abstract

1314988 Starting, stopping, feeding work in sewing machines BROTHER KOGYO KK 11 Aug 1970 [12 Aug 1969 10 Sept 1969 23 July 1970 24 July 1970 27 July 1970] 38627/70 Heading D1G A sewing machine, having means for feeding the work, for cutting the thread, and for driving the machine and stopping it with the needle in a selected position, has control means responsive to the operation of a pedal to reverse the feed to oversew the stitch seam. The mechanism disclosed has fluid operated devices and electrically operated devices which cause, when the pedal (134, Figs. 1 and 7 not shown) is rocked forwardly, the presser foot (25, Fig. 2 not shown) to be lowered and the machine driven at high speed with the feed mechanism operating first in reverse and then forward, to oversew the start of the seam. After a desired seam length has been sewn rocking the pedal in the opposition direction serves to reverse the feed direction to oversew the seam end before feeding again in the normal direction, the machine then being driven at a slow speed to a needle lowered position where the threads are engaged by the thread cutter and severed, the needle then rising to an upper position where the machine is braked. Alternatively, the machine may be stopped with the needle lowered. Machine driving, starting and stopping. The machine is driven at high speed by a motor 41 or at slow speed by a clutch brake motor (70, Fig. 6 not shown) which drives a worm engaging the wormwheel 55. A shaft 58 carrying the drive pulley 62 and a clutch plate 47 is slidable in the casing portion 57, by a lever device 100 connected to the pedal, to engage the plate 47 with either the slowly rotating wormwheel 55 or the motor flywheel 47. The device 100 comprises a bent lever 101 pivoted at 105 to the motor frame and provided with an extension 111 pivoted thereto at 112 carrying a switch 53 and connected to the pedal. Pivoted at 105 is a further lever 122 engaging an operating groove 59 for the motor clutch mechanism and connected at its other end to a fluid pressure operated piston and cylinder device 130, 129 which permits the levers 101 and 122 to be misaligned to maintain the clutch plate 60 against the flywheel 47 when the pedal is released during the seaming sequence. A modified form of the pedal linkage is also described (Figs. 14A, B not shown). Feed, reversing and regulating: Fig. 11. The feed dog 164 is mounted on a feed bar 163 receiving feed lift and advance movements from shafts 165 and 162 respectively, the latter being driven from a cam 161 on the machine arm shaft through feed adjusting means 167 having a dial 167a. A feed reversing shaft 169 connected to the means 167 by arm 170 may be operated manually by a lever 168 or, in the controlled sewing of the seam, by a fluid pressure cylinder 171 coupled to an arm 175 on the shaft, a solenoid actuated control valve 177 for the cylinder being controlled by electronic circuitry (Figs. 12, 13 not shown) to provide the seam oversewing at the beginning and end of the stitching.