GB761747A - Improvements relating to polarised electromagnetic relays - Google Patents

Abstract

761,747. Electromagnetic relays. WESTINGHOUSE AIR BRAKE CO. Dec 14, 1954 [Jan. 22, 1954], No. 36135/54. Class 38(5) A polar relay comprises a recessed insulating base 2 carrying pole members 11, 12 connected to opposite poles of a permanent magnet 35 and having pole faces 13, 14. The upper ends of the member 11, 12 are connected, respectively, by L-shaped magnetic straps 15, 16, to cores 23, 24 having pole pieces 29, 30 provided with pole faces 31. 32. The pole faces 13, 31 and 14, 32 are positioned opposite each other a small distance apart to provide a pair of air gaps in which an armature 37 oscillates. The cores 23, 24 have two sets of windings 25, 26 and 25a, 26a, the windings of each set being connected and each set operating the relay in the same manner, the two sets permitting control of the relay from two separate sources. Energization of either set of windings with current of appropriate polarity causes the armature to move from one extreme position to the other. The control flux flows in the same direction across both air gaps in two loops 31, 23, 15, 11 and 32, 24, 16, 12. The insulating armature spindle 36 is pivoted at the upper end in a bearing 20 carried by a non-magnetic bridge 19 secured to the pole members 11, 12, the lower end being supported in a bearing 9 situated at the junction of four ribs 7 upstanding from the front of the base 2 A contact-driving member 38 formed on the spindle 36 extends through an opening in the front of the base 2 and has slots 39 receiving the free ends of movable contacts fixed to terminal posts 42. Each movable contact comprises a spring blade 41 carrying, near its root, a blade 44, the free ends of the blades 41, 44 being biased apart and received under tension in a slot 39. The blades 41, 44 operate between fixed blades 45 connected to further posts 42, the movable blade tension eliminating contact bounce. A front cover 46 sealed to the base 2 has a window 48 for observing the contacts the rear of the relay being enclosed in a cover 51 sealed to the back of the base. The relay is mounted by plugging into an insulating support 55, an opening 56 receiving the cover 51 and holes 58 receiving prongs 43 connected to the terminals 42. Holes 59 receive prongs 28 connected to the ends of the windings 25, 26, 25a, 26a. The prongs 28, 43 are engaged by contact lips mounted in the support 55 behind the holes 58, 59 (Fig. 3. not shown). To ensure the correct relay is inserted in the proper manner in the support 55, a flat ledge 62 in the support co-operates with a corresponding surface on the rear end of the cover 51, and a particular arrangement of pins 65 on the support are received in corresponding notches formed in the cover 51 (Fig. 7, not shown).