GB1219556A - Improvements in or relating to magnetic contact units - Google Patents

Abstract

1,219,556. Electric contact devices. STANDARD TELEPHONES & CABLES Ltd. 6 June, 1969, No. 28697/69. Heading H1N. A magnetic contact unit, for operation on energization of a coil or movement of a component of a magnetic circuit which includes a permanent magnet, has an inner magnetic member 40 extending through an aperture in an outer magnetic member 42 in which it is located by a non-magnetic member 41 and a resilient magnetic diaphragm 30 forming the movable contact armature of the contact unit and being formed as a disc with peripheral arcuate arms 31 arranged so that when the disc is attracted to the magnetic member 40 the free ends of the arms rock on a conducting component such as the member 42. In Fig. 4 the member 40 is also an annular fixed contact cooperating with the armature contact disc and the U-shaped free ends 32 of the arms 31 rock on the outer member 42 to close the contacts on attraction between the disc and the member 40. In Fig. 6 the disc 30 is stressed into engagement with one fixed contact 50 and is attracted on operation to the inner fixed magnetic contact 40 to form a change-over contact unit with flux transfer between the disc 30 and the outer magnetic member 42 assisted by extensions 67. The inner magnetic member is not a contact in a normally closed contact set (Fig. 5, not shown). The fixed contact tip may be made from a disc having a layer of gold, copper, silver or silver cadmium oxide on permalloy B welded on the end of the member 40 (Fig. 7, not shown). The contact unit may be used in relays of the types described in Specifications 1,094,334, 1,098,145, 1,099,081, 1,115,401 and 1,131,928 and switches having movable magnets or magnetic components as in Specification 1,213,699.