GB850987A - Improvements in electric snap-action switches - Google Patents

Abstract

850,987. Snap-action switches. ILLINOIS TOOL WORKS. July 24, 1958 [July 24, 1957], No. 23894/58. Class 38 (5). A switch has a pivoted rocker movable between two extreme positions to carry a contact into and out of engagement with a fixed contact, two slidable catches urged by springs to positions where each can lock the rocker in one of its extreme positions, and an actuator acting on the rocker to move it in opposite directions, the rocker snapping to its opposite position when released by displacement of a catch during the final stage of movement of the actuator. The rocker is a plate 72 with slots receiving locking plates 59 which have apertures 70 engaging lugs 76. The plates 59 are pivoted on a pin 57 carried by a yoke 32 secured to a central terminal 18, the arms 40 of the yoke passing freely through the apertures 74 in the plate 72. In a three-pole switch, as shown, the plate 72 has three pairs of springs 96 bearing on the ends of three contact members 84, the middle one of which is pivoted on the pin 57, and the outer two of which are pivoted on pins 82 carried by yokes 80 on outer terminals 18. The members 84 have contacts 88, 90 co-operating with fixed contacts 28, 30, and are locked in their respective end positions by spring-biased bars 50, 52 received in slots 46, 48 in the yoke arms 40. In the position shown, projections 64 on plates 59 are hooked over bar 52, and in the opposite position, projections 62 hook over bar 50. The contacts are operated by a lever 104 sealingly arranged in the casing (Fig. 2, not shown), and having a spring-urged plunger 110 bearing on the plate 72. When the lever is tilted counter clockwise from the position shown, the spring 108 is strained, until when the lever has moved overcentre, the plunger 110 pushes bar 52 to the right, to release the plates 59, whereupon the rocker 72 and contact members 84 are snapped to their right-hand position where they are similarly latched. The terminals 16, 18, 20 are insulatingly mounted in a metal base 12 by glass inserts 24.