Patent GB-262488-A (GB)
Title: Improvements relating to electric switches
IPC: H01H71/56
Filed: 1925-08-06
Abstract: 262,488. Cox, F. B. Aug. 6, 1925. Addition to 249,232. Automatic circuit-breakers; springs, arrangement and disposition of; controllers.-In switches of the type described in the parent Specification one or more of the secondary members are in the form of a percussive device adapted to actuate the corresponding switch members after release or aetuation by the automatic device by being moved rapidly by the spring connecting the percussive and primary members. As shown in Fig. 1, the percussive member C1 when released by the no-volt magnet E2 is moved rapidly by the spring D1 connecting it to the coaxially pivoted primary member A1 and a pin c<4> on the member C1 engages the switch arm B1 and moves it to the off position. The member Cl is returned to its retained position by rotating the primary member A1 in an anti-clockwise direction when the pin c4 engages a cranked extension b5 of the switch arm B1 and returns it to the closed position; a subsequent clockwise rotation of the member A1 brings the spring across the dead-centre so that the parts are in readiness for a subsequent automatic operation. Instead of the no-volt magnet acting directly on the percussive member it may control a pivoted latch coacting with this member. If an overload release is fitted as shown in Fig. 4, the spring D4 is brought into the position shown and the primary member A4 is retained in position by a detent H or by a no-volt magnet. On overload the core g1 of the overload coil G strikes the percussive member moving the spring across the dead-centre so that it can cause a rapid movement of the percussive member C4 and a consequent opening movement of the switch member B4. The primary member may itself control contacts in either or both of its alternative positions, and these contacts may be arranged in series with the contacts controlled by the secondary switch arms so that the switch may operate as a loose-handle circuit-breaker or change-over switch. The primary member may be provided with a return spring as shown in Fig. 9, the actuating handle A9<1> having a return spring a7 may be separate from the primary switch arm A9 having its own return spring a6, the handle A9 on release tripping a pivoted latch a5 retaining the primary member in the position shown. In Fig. 10 the percussive member C10 is retained by a no-volt magnet E10 and an overload magnet G10 is placed adjacent to the primary member A10 so that on overload the core g1 strikes the arm A10 moving the spring B10 across the deadcentre position and breaking the circuit at contacts a1 in series with contacts b1 controlled by the secondary switch member B10. The primary and secondary members may be pivoted on the same or adjacent axes. The switches described may be constructed in the manner described in Specification 254,776, primary contacts being mounted on the rotatable shaft and secondary contacts on a rotatable sleeve thereon which passes through the end casing member, the percussive member being loosely held on the protruding end of the operating shaft. Such a switch may be adapted to function as a star-delta motor starter. Specifications 250,696 and 262,698 also are referred to.