GB1327631A - Electrical switches - Google Patents

Abstract

1327631 Retractive switches JOSEPH LUCAS (INDUSTRIES) Ltd 19 April 1971 [10 March 1970] 11407/70 Heading H1N [Also in Division H2] A double-pole change-over switch, particularly for a vehicle electrical system wherein two twelve-volt batteries are normally in parallel but are connected in series to energize a twentyfour-volt starter motor (see Division H2), comprises a retractive operating rod 15 slidably carrying a first bridging contact member 21 co-operating with a first pair of fixed contacts 25, 26 and a second bridging contact member 22, loose on a carrier 16 secured to the rod 15, for co-operation with a second and third pair of fixed contacts 27, 28 and 29, 31, respectively, a resilient member 24 urging the two bridging contacts apart, and a stop member 18 on the rod 15 is arranged to engage the bridging contact 21 but is spaced therefrom by a distance less than that of the second bridging contact from the third pair of fixed contacts 29, 31, such that when the rod 15 is moved the second contacts 27, 28 are opened prior to opening of the first contacts 25, 26, and the first contacts 25, 26 are opened before the third contacts 29, 31 are closed. Preferably a fourth pair of contacts 32, 33 are provided so as to be bridged by member 21 after member 22 has bridged contacts 29, 31. The rod 15 is urged by a spring 17 which is stronger than spring 24, and the spacing of contacts 32, 33 from member 21 is greater than the sum of the distance between stop member 18 and member 21 and the distance between contacts 29, 31 and member 22. The switch is specifically designed for use in the stated vehicle electrical system and internal connections 45, 47 and 49 are therefore provided between certain contacts, as shown, while exterior terminal tags 46, 52 and 53 and terminals 48 and 51 are also provided. The rod 15 may be operated manually or by the armature of an electromagnet (not shown) carried on the cover 13.