GB1367626A - Electric switches - Google Patents

Abstract

1367626 Switches held set and freed mechanically CAV Ltd 19 Nov 1971 [1 Dec 1970] 56982/70 Heading H1N A cam operated switch comprises a bridging contact unit 16 (Fig. 2) carrying two sets of bridging contacts 18 biased away from sets of fixed contacts 14, 15 by spring 19; and a resiliently biased latching mechanism 27 mounted for free rotation around the shaft 21 which carries the operating cam 23. The rotation of the shaft 21 is limited to about 180 degrees anticlockwise by stop member 24 co-operating with portion 25. A blade 31 secured to the housing wall 12, passes below the cam and has an edge which abuts the face 33 of the latching member, retaining it against the action of the resilient bias provided by spring 28. On operation, the cam depresses the blade 31 and the push member 32 below it, this action being transmitted to the contact carrier 16 via the leaf spring 20. After engagement of the contacts, further cam rotation causes the blade to disengage the latch which is free to rotate, within the limit imposed by stop members 29 and 30, and latch the switch closed, excess movement of the push member being accommodated by the spring 20. Reverse rotation of the shaft causes the cam, towards the end of its travel, to engage a pin 34 on the latching member and reset it on the spring blade 31, the contact member being released and disengaging the fixed contacts as the spring blade lifts. A further switch 36, e.g. a microswitch. may be operated by a cam track on a further portion of the cam to open a circuit prior to opening of the main contacts.