GB566192A - Improvements in or relating to alternating current power switches - Google Patents

Abstract

566,192. Snap-action switches; induction relays. LANDIS & GYR SOC. ANON. Oct. 27, 1942, No. 15054. Convention date, Nov. 13, 1941. [Class 38 (v)] An A.C. power switch suitable for remote, manual or automatic control, is adapted to be closed rapidly by spring energy released by a motor, automatic resetting of the snap-mechanism occurring during opening of the switch at a slower rate than the closing thereof. When the induction relay 1 is energized, disc 1a is rotated in the direction P and through a disc 9 and friction clutch 9a fast on shaft 14, rotates the latter through nearly a complete turn until an arm 17 thereon is arrested by a pin 19. During this rotation, a spring 10 is tensioned and a pin 5a on an eccentric 5 is rotated to operate a spring latch 8 and free a lever 4, 4a, whereby a contact 3 on a blade spring 6 rapidly engages a fixed contact 7. When relay 1 is de-energized, or if its voltage fails, spring 10 drives the shaft 14 reyersely and, by means of the eccentric 5 and a roller 4b, raises lever 4, 4a to impart a slow break to contact 3, which is relatched open by latch 8. The inertia of the parts assists the slow movement and shocks are absorbed in the friction coupling 9, 9a. In Fig. 2, movement of control switch 20 to position a makes, over contacts 25, 24a, the circuit of relay 1 which, at the end of the switching operation, is de-energized by cam 24 changing contact 24a over to contact 26. Each switching operation is produced by a half-turn of shaft 14 in the same direction, and a two-lobed cam 11 fast on shaft 14 ensures return or completion of each movement. The driven wheel 13a is free on the shaft and drives it by means of the pins 22, 23, and the control member 5 has two rollers 5a, 5b, the former serving to hold the contact 3 open. To close, switch 20 is moved to position b to energize relay .1 over contacts 24a, 26, the roller 5a releasing lever 4, 4a to give the quick make. By fixing disc 13a to the shaft or screwing pins 22, 23 together, gearing 13 may be made to serve as a brake to provide uniform movement of shaft 14. Alternatively, Fig. 3 (not shown), a further disc fixed to shaft 14 may drive one of the shafts of gearing 13 through further gearing including a ratchet-and-pawl device to make the gearing serve as a brake ; one of the rollers of member 5 is in this case dispensed with. The contacts may be of silver and a flat movable contact may co-operate with a convex fixed contact. Each contact-pair of a multi-pole switch may have a spark chamber.