GB1462503A - Electromagnetic relays - Google Patents

Abstract

1462503 Polarized bi-stable electromagnetic relays STANDARD TELEPHONES & CABLES Ltd 18 April 1974 16996/74 Heading H1N A polarized bi-stable magnetic holding relay, Fig. 1, comprises a permanent bar magnet 30 located within a ferromagnetic shunt tube 32 to form a first magnetic circuit, and a sealed contact unit forming part of a second magnetic circuit, in conjunction with the magnet, via inner and outer member 11, 13 and a resiliently urged open diaphragm type armature contact 16, 17, 18 of the unit (Fig. 2, not shown), an outer casing 41, an end plate 40 and a screwthreaded adjuster 42. At least one winding 36 on a bobbin 33 surrounding the shunt tube 32, and contained within the outer casing, is provided to operate the relay contact which is released by pulsing the winding or windings in the appropriate sense and the adjuster 42 is used for the initial operating setting adjustment by adjusting the relative magnetic reluctance of the two magnetic circuits after which the whole assembly may be encapsulated in resin. The various tubular parts are force fit within one another, insulation washers &c. separate out the magnetic and electrical paths and the cooperating contact making surfaces may be hard gold plated on nickel. A changeover type contact unit (Fig. 3, not shown) comprises additional inner and outer members (50, 52) assembled in opposed relationship on the side of the diaphragm remote from the bar magnet and with the fixed inner contact (50) normally in pressure contact engagement with the diaphragm. Specifications 1,094,334, 1,115,401, 1,098,145 and 1,131,928 are referred to.