GB1302255A - - Google Patents

Abstract

1302255 Magnetic contact devices C P CLARE & CO 19 May 1970 [28 July 1969] 24183/70 Heading H1N A sealed magnetic control unit has first and second polepieces sealed in an insulating housing and a rigid armature mounted on a spring coupled to the second polepiece and the armature is normally positioned to provide gaps between itself and each of the polepieces. The spring may be of ferromagnetic material. The mercury wetted contact unit of Fig. 1 has a J-shaped armature end 22A mounted on the spring 23 adjacent the end face 28 of the polepiece 26 to provide a small gap of large area magnetically in parallel with the spring and in series with the operative air gap such as 29. The unit may be polarised by permanent magnets to be centrestable, bistable or single position stable and when the armature 22 is attracted to the polepiece 16 the attraction of the end 22A to the polepiece 26 assists armature movement. An attracted armature type relay (Fig. 3) may have an L-shapeded armature end providing a gap 58 in parallel with its spring 53. The armature 52 has a non-mercury wettable spacer 49 for engagement with the housing 42.