GB779140A - Improvements in and relating to electric winders - Google Patents

Abstract

779,140. Winch overwind. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 17, 1954 [April 10, 1953], No. 9797/53. Class 78 (5). [Also in Group XXXVII] In a system of control for operating a winch in which overwinding switches F, G are arranged to limit the travel of the load in either direction, there is provided a brake interlocking switch L which is closed when the brake is applied but operates to break the motor circuit when the brake is taken off, and an auxiliary switch H which operates when the controller is in position to drive the load out of the overwind, to close an alternative path across the interlocking switch L whereby the brake can be released without breaking the circuit. As shown, there is inserted in the electric control circuit AB the following.: forward switch D which opens in the forward direction of travel, forward-overwind switch F, reverse switch H which closes in the said reverse direction brake interlock L which is closed when the brake is on, and forwardoverwind backing out switch J. The switches G, E, K and I form a corresponding symmetrical circuit which operates in the same way for the opposite direction of travel. Thus when an overwind occurs in the forward direction, F automatically opens, and J is then operated to change the circuit to that of Fig. 3 wherein switch L acts to prevent the release of the brakes. If, however, the motor is put into reverse to come out of the overwind, then (Fig. 4) switch H shunts switch L and the brake may now be released without breaking the circuit. Specification 206,244, [Class 78 (v)], is referred to.