GB970089A - Wiping contact rotary electric switch - Google Patents

Abstract

970,089. Mechanical switches, without quick action. ANSUL CO. June 7, 1962, No. 22051/62. Heading H2B. The stator 26 of a rotary switch comprises two annular members 50 each having moulded therein a plurality of fixed contacts 48 with offset, slightly raised, insulating segments 52 therebetween. A detent path 54 is formed at the junction of the two members 50 with valleys 58 and peaks 56 aligned respectively with contacts 48 and insulating segments 52. The members 50, with two insulating spacers 38 and 40, are clamped between end walls 30 and 32 by means of screws 42. The end walls form bearings 34 and 36 for a shaft 24 having a square-section portion on which the rotor 28 is carried. The rotor has radial slots 62 circumferentially spaced to accord with the fixed contacts 48. Each slot 62 coincides with three " holes ". which form grooves in the side walls of each slot. Any central hole 64 can accommodate a spring-loaded detent 60, to cooperate with path 54 on the stator, while the outer holes 66 accommodate springs 72 urging a U-shaped contact 46 to bridge selected contacts 48. The insulating segments 52 are axially spaced from the rows of contacts 48 so that different parts of contact 46 wipe the contacts and insulating segments and metal tracking is prevented. The insulating segments 52 also stand slightly proud of the contacts 48 and thus lift the bridging contact 46 as it leaves contacts 48, thereby reducing arcing. The gap between rotor 28 and stator 26 is small to assist arc-quenching. In a modification (Figs. 7 to 10, not shown) the moving contact comprises two mutually sliding U-shaped members individually spring-loaded and with extended curved contact surfaces at their ends such that one engages the succeeding fixed contact before the other leaves the previous fixed contact, thus providing a make-before-break action.