GB1360837A - Lock-out mechanisms for switches - Google Patents

Abstract

1360837 High voltage switches REYROLLE PARSONS Ltd 19 Oct 1972 [19 July 1971] 33810/71 Heading H1N A switch having butt contacts 11, 12 is provided with an automatic lock-out mechanism operated by the release of a spring loaded latch 18 held against release by a detent member 16 coupled to the movable butt contact 11, the latch being released by the travel of the detent member on closing of the switch after a predetermined amount of contact wear has taken place. The switch may be a high voltage switch having an evacuated enclosure or a sealed enclosure containing an electro-negative gas which may be at a pressure above atmospheric. The detent member may be a rod against which the pivoted latch 18 bears, the latch being coupled by a link 24 to the lock-out mechanism. A second spring loaded latch not coupled to the lock-out mechanism may be released when a lesser degree of wear has occurred to provide a warning indication. Alternatively, means may be coupled to the detent member 16 for providing a remote indication of contact wear. In a further arrangement Fig. 2 (not shown) the detent is a pivoted cam lever having a cam surface against which the latch member engages. In this case the angular position of the latch member changes as contact wear occurs and may cause the operation of a potentiometer to effect electrical indication of contact wear.