GB564779A - Improvements in and connected with electric tumbler switches for alternating currentcircuits - Google Patents

Abstract

564,779. Tumbler switches. CRABTREE & CO., Ltd., J. A., McLOUGHLIN, H. F., HARRISON, B. G., and MORGAN, R. W. June 1, 1943, No. 8744. [Class 38 (v)] In order to provide a slow initial movement to a short gap followed by a rapid enlargement of the gap for isolating purposes, the bridge p of a tumbler switch having abutting contacts has abutments n adapted to .co-operate with cam surfaces i<1> on a U-shaped member 'i forming part of'the spring-toggle mechanism. The contact rocker b is pivoted to the dollypivot c and a telescopic plunger g is pivoted to a pin f between the depending arms of the dolly and surrounded by a spring h. The plunger g passes through a guide kin the member i which has stubs extending laterally into pear-shaped slots m in the limbs of the rocker. In moving from position 1 to position 2, the cam i<1> engages abutment n and remains in engagement until position 3 is reached, during which time the small gap x is slowly produced. After the dead-centre is passed, movement to position 4 causes a rapid fly-over to the chain-line position where, according to the Provisional Specification, other contacts may be engaged. A disc contact p with conical flange makes abutting contact with fixed contact q so as to avoid rubbing contacts.