Patent GB-640751-A (GB)
Title: Improvements relating to the control of electric motors driving flat type hosiery machines
IPC: H02P5/68
Filed: 1948-05-03
Abstract: 640,751. Brush-gear for dynamo-electric machines. BRITISH THOMSON-HOUSTON CO., Ltd., HILL, C. V., and LOWE, G. F. May 3, 1948, No. 12112. [Class 35] [Also in Groups VIII and XXXVII] A Schrage motor for ' driving a hosiery machine is provided -with brush-shifting mechanism for varying the speed of the motor and a servo mechanism comprising a " slave '' member operatively connected to the brushshifting mechanism and a " master " member for connection to a control mechanism on the machine, the servo mechanism being arranged to provide one definite setting of the " slave " member corresponding to any particular setting of the " master " member within the ranges of operation, so that the servo mechanism causes the brush-shifting mechanism to take up a setting corresponding to the setting of the control mechanism and to follow the movements of the latter, the energy required for shifting the brushes being derived from a source controlled in accordance with the position of the " master " member. A Schrage motor 1 drives a hosiery machine through a gear 3 and is mounted end-to-end with a pony motor 2 which has a clutch 5 operated by solenoid 6, whereby the two machines may be mechanically coupled. Brush-shifting mechanism for the motor 1 comprises levers 8 and 9 adapted for high and low-speed operation respectively. The position of the lever 8 may be adjusted manually, that of the lever 9 being regulated by servo-mechanism 10. An electric switch 9a which is associated with the brush-shifting mechanism, operates solenoid 6 to couple the motors 1 and 2 at a low speed of motor operation. The servo-mechanism 10 comprises a regulating member constituted by the adjusting element of a hydraulic valve 11, and a regulated member consisting of a piston in cylinder 12. The regulated member is moved by a bell-crank 13, the piston being coupled to the lever 9. The servo-mechanism is such that fluid under pressure is admitted to each side of the piston the reciprocating motion of which is a copy of the motion of the valve member. The hydraulic fluid is contained in reservoir 17 and is pumped to the servo-mechanism through pipe 18 by pump 19 which is continuously driven by motor 2. A return pipe 21 is provided. A pattern control chain (Fig. 3, not shown), passes over a drum and carries control studs of two heights which are arranged to lift two bell-crank levers. The drum is rotated intermittently so that the levers are operated at pre-determined intervals depending on the arrangement of the studs on the chain. The levers are linked with quadrant arms which have cam-surfaces co-operating with setting-screws mounted on a spring- biassed control arm. This arm is coupled to the bell-crank 13. When no studs are engaged by the bell-crank levers the regulating and regulated members of the servo-mechanism are held in such a position that the brush shifting lever 8 is adjusted to allow manual operation through the lever 9. The pattern control chain makes one circuit for each cycle of machine-operation and the studs are arranged to provide three low operating speeds ; a low speed for plating, a lower speed for fashioning, and a still lower speed for welt-turning or carrier changing. The Schrage motor may be stopped automatically when one of the control studs engages a bell-crank lever which is coupled to a cam-operating a control switch. This switch may be closed by means of mechanical linkage with the lever 8, the cam, which is slidable upon a shaft, being pushed out of engagement with the switch which is closed by a spring. A cam-shaft which is moved laterally when it is desired to initiate fashioning operation is so interlocked with the control mechanism of the Schrage motor that the reduced speed setting is allowed to become effective before the cam-shaft is shifted. When changing back to normal speed operation, the control gear is retained at the fashioning-speed setting until the cam-shaft returns to its normal position.