GB252649A - Improvements in or relating to electromagnetic mechanisms - Google Patents

Abstract

252,649. Automatic Telephone Manufacturing Co., Ltd., and Hudd, A. E. Nov. 22, 1924. Contact - making relays; electromagnetic switches.-In a polarized relay the core 21 carrying the energizing coil is mounted in bearings in a fixed frame at its ends 22, 23 and has polar projections 24, 24<a> normally resting on the poles, of a fixed permanent magnet 26. The rocking core is provided with a non-magnetic contactcarrying bars 32, 32<1> co-operating in opposite extreme positions with sets of fixed relay contacts. Normally the relay is held in the position shown with contacts 32<1> in engagement by gravity assisted by the attraction of the permanent magnet and the holding force is increased with current in one direction passing through the winding but if current passes in the opposite direction so that the polarities of the projections 24, 24a and of the adjacent magnet poles are alike these projections are repelled until they engage a fixed magnetic bar 27 which completes the magnetic circuit through the core and brings the relay contacts 31 firmly into engagement with the corresponding fixed contacts.