GB455309A - Improvements in and relating to electric switches particularly for starting electric motors - Google Patents

Abstract

455,309. Actuating controllers ; switches retained set. BRITISH THOMSONHOUSTON CO., Ltd., Crown House, Aldwych, London, WISE, W. L., 7, St. Albans Road, Moseley, Birmingham, and BENNS, H. V., 40, Holbrook Avenue, Rugby. April 18, 1935, No. 12016. [Classes 38 (iii) and 38 (v)] A motor control switch comprises a pair of carrier members b, b<1>, Fig. 1, each carrying a contact c, a handle for moving the members simultaneously in opposite directions, the members being arranged to allow of engagement of one of said contacts with a fixed contact f before the other movable contact reaches a further fixed contact f, and yieldable means to cause said last - mentioned movable contact to move out of engagement with its fixed contact without causing disengagement of the first mentioned contact when the handle is released. The switch which controls an electromagnetically operated starting or reversing switch provided with maintaining contacts is operated by a lever n, Fig. 4, pivoted at p and having a pin q engaging a pivoted lever g. The lever g has a T-extension carrying two driving pins h, h<1>, which project through slots in the base of an insulating block in which the members b, blare arranged to slide, the lever g be rotated by the lever n and thereby causing the members b, b<1> to slide simultaneously in opposite directions. The lever n also has a roller t engaging pawls s, s<1> which are biassed inwardly by a spring v. When the lever n is rotated in one direction the roller t first lifts one of the pawls s, s<1> and passes under it until it engages the face x or x<1> and then the pin q operates on the face y or y<1> of the pawl s, s<1>, the members b, b<1> being moved so that the lower contact c on one member first engages its fixed contact f, and then the upper contact c of the other member engages its fixed contact f. This is the starting position. When the handle is released the spring v returns the lever n to the intermediate running position in which it is held by the opposing force on the faces x, y or x<1>, y<1>. By the provision of the two sets of movable and fixed contacts reversal may be effected. The contacts c, Fig. 3, which are located in slots in the carriers b, b<1> are H-shaped and the two contacts on each carrier are forced apart by springs e.