GB156346A - Improvements in and relating to electric motor controllers - Google Patents

Abstract

156,346. British Thomson - Houston Co., Ltd., (General Electric Co.). Oct. 15, 1919. Gearing, ratchet. - Consists in an arrangement of ratchet and spur gearing connecting an operating handle to a drum controller shaft, which has the following functions:- (1) To-and-fro action of handle produces slow forward movement of controller. (2) After a certain range, or optionally at any time, continuous forward movement of handle produces quick forward movement of controller. (3) Continuous backward movement of handle produces quick backward movement of controller. In the construction shown the first function is performed by a pawl 21 driving a ratchet wheel 12, the pawl being pivoted on a frame 17 which turns with the handle 10 about an axis 10<1>, and the ratchet being in connection through spur wheels 13, 14 with the controller shaft 11. The second function is performed by a stop 24 attached to the frame 17, encountering the edge of a toothed sector 15 in gear with a smaller spur wheel 16 on the controller shaft. In normal starting the movements of the stop are idle until the first part of the forward travel has brought the sector 15 within range, and during the first part of the travel the extent of the handle is limited by a stop pawl 32 which drops into teeth of a stationary ratchet 31. The action of the pawl 32 is superseded, after a definite range, by its arrival on the smooth part of the ratchet 31. If continuous movement is desired at an earlier stage, the operator throws over a releasing handle 36, which lifts the stop-pawl clear of the ratchet. The third function is performed by a lug 25, similar to the lug 24, but adapted to encounter the opposite edge of the sector 15 when the handle is turned back. A pin 26 meets the pawl 21 and lifts it clear of the ratchet 12 in order that these parts may run back freely.