GB741057A - Improvements relating to electro-magnetic relays - Google Patents

Abstract

741,057. Electromagnetic relays. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., and EVERETT, D. B. Sept. 14, 1953 [Oct. 20, 1952], No. 26236/52. Class 38(5) A D.C. relay comprises a U-shapea core structure 2, 1, 16, energized by coils 3, 17 to produce opposite poles at pole pieces 5, 15 provided on the ends of the cores 2, 16. A pair of armatures 7, 8 pivotally mounted at 6 have their free ends 10, 13 resting on opposite poles 9, 12 of a permanent magnet 11 when the coils 3, 17 are not energized. The magnet 11 is supported from the pole piece 15 by brackets 14, preferably of magnetic material. When D.C. of one polarity is applied to the coils 3, 17 to produce, e.g. a south pole at 15 and a north pole at 5 the armature ends 10, 13 both become north poles whereby armature 8 is raised towards contact piece 15 and operates its respective contact set (not shown) whereas armature 7 is held the more firmly by the magnet 11 and its contact set remains unoperated. Conversely, D.C. of opposite polarity causes the contact set associated with armature 7 to be operated. To prevent simultaneous operation by both armatures by an abnormal heavy current, a locking device is provided, Fig. 2, comprising a two-armed lever 19 pivoted to the pole piece 15 at 21, the lever ends 18, 20 co-operating with the armature ends 10, 13, respectively. Hence after one armature has been operated, subsequent operation of the other armature by an increase in current is prevented since the operated armature tilts the lever 19 towards the other armature. Specification 623,167 is referred to. The Provisional Specification also refers to Specification 517,000.