GB564531A - Improvements in and relating to switching mechanism particularly suitable for electric discharge lamps - Google Patents

Abstract

564,531. Retractive switches. BRITISH THOMSON-HOUSTON CO., Ltd. July 20, 1943, No. 11775. Convention date, July 21, 1942. [Class 38 (v)] A switch has pairs of contacts closed by rotation of two elements, which may be moved together to close both circuits, one remaining " closed," while the other returns to " open " position on release of operating means. As shown, the rotatable elements 36, 55 are insulating discs mounted on a spindle 26, the ends of which are borne by plates 18, 19. Plate 18 bears pairs of contacts 27, 30, 40, 43, while plate 19 a pair 48, 49 spaced diametrically. Disc 36 bears oppositely situated shorting members 35 which coact with the contact pairs on plate 18. Disc 55 has secured to it a shorting member 56, the arms 57 of which coact with contacts 48, 49 on plate 19. Discs 36, 55 lie together in the assembly, with bearing rings 61, on each, touching, forming an annular channel around the periphery, in which runs a pull chain, the end of which is held by a member 63 having pins 65 protruding on each side. The pins lie in a slot 66 on disc 36 and in one of a series of ratchet steps 67 on disc 55, respectively. The member 63 is held by a tension spring 62, the other end of which is secured to a yoke 13 in which the discs and plates are assembled. On pulling and releasing the chain, the disc 36 moves to bridge the contacts 27, 30 and 40, 43, and breaks on the return, moving back and forth by reason of the pin 65 in the slot 66. The disc 55 is, however, rotated, on pulling, to close contacts 48, 49 and remains in that position on return of the chain, until a second pull. The switch is described as applied to starting discharge lamps, contacts 48, 49 controlling on and off while the contacts 27, 30 and 40, 43 place the filaments in series for as long as the chain is held pulled.