Patent GB-765661-A (GB)
Title: Improvements in or relating to electromagnetic relays
IPC: H01H51/06
Filed: 1952-12-05
Abstract: 765,661. Electrically-released switches. S IEMENS & GENERAL ELECTRIC RAILWAY SIGNAL CO., Ltd., and CANDLER, J. E. Dec. 1, 1953 [Dec. 5, 1952], No. 30938/52. Class 38(5) A relay 1, Fig. 1, comprises an armature 9 carrying a permanent magnet 19 and pivoted at 11 to a core 6 having an operating coil 5. A part 15 of the core carries an unlatching coil 16 and has a pole 17 co-operating with the magnet 19 whose magnetic axis lies along the length of the armature. The armature, which operates bridging contacts 13 through a member 14, is held in the attracted position upon de-energization of the coil 5, by the magnet 19, and is released by energizing the coil 16 which produces in the pole 17 a polarity which repels the adjacent pole of the permanent magnet. Fig. 1 shows two identical relays 1, 2, the armatures 9, 12 being interlocked by a pivoted bar 21. The operating coil 5 and unlatching coil 27 are connected together in series (or parallel) and energized through contacts 22' across terminals 26, 28, whilst coils 16, 24 are similarly connected and energized through contacts 23 across terminals 26, 25. The contacts 22, 23 are respectively controled by the armatures 9, 12 and arranged to be closed when the associated armature is released. Hence if a voltage is impressed on terminal 25 coils 16, 24 are energized to release armature 9 and attract armature 12 the latter being held operated by a permanent magnet 32 the contacts 23 being opened and contacts 22 closed. Thus if now a voltage is impressed on the terminal 28 a similar sequence of events returns the parts to the initial condition. In a modified arrangement, Figs. 2, 3, employing two identical relays 1, 2 positioned side by side, the operating coils 5, 24 are horizontal and the unlatching coils 16, 27 vertical. Each permanent magnet, e.g. magnet 19, has a vertical magnetic axis, is mounted on one side of the armature 9, and has a pole piece 36 co-operating with the pole 17 of the coil 16, the latter being positioned over the other side of the armature. A shoulder 37 on the core 6 co-operates with the pole piece 36 so that when the armature 9 is released a magnetic circuit is completed through the magnet 19 and thus the relay is magneticaly latched in the released position. An arm 20 on the bar 21 operates the contacts 22, 23, the arrangement functioning similarly to Fig. 1. Two windows may be provided in the front of the relay housing 35 to observe the ends of the bar 21. In a modification of Figs. 2, 3, shown in Figs. 5. 6, the operating coils 5, 24 and unlatching coils 16, 27 are connected in separate circuits, the contacts 22, 23 each comprising a pair of fixed contacts each fixed contact being connected to a respective coil so that in one position of the arm 20 (shown) circuits are prepared for energizing the coils 5, 27, whereas in the other position of the arm the circuits of coils 16, 24 are prepared. The circuits of the operating coils 5, 24 include, respectively, additional switch contacts 77, 76. these contacts being operated by a link 74 pivoted to a pair of vertical auxiliary interlock armatures 71, 72, The armatures 71, 72 are associated respectively with unlatching coils 16, 27 such that when a coil is energized its armature is attracted by an upturned part 73 of pole piece 17 whereupon the other armature is removed from its pole piece by the link 74 and the latter operates the contacts 76, 77. As shown, armature 71 is in the attracted position and the contacts 76 are closed and contacts 77 open. the auxiliary armatures 71, 72, when attracted, extend over the ends of their respective armatures 9, 12 and serve to lock the latter in: the released position. Fig. 6 shows the armature 71 locking the armature 9. Thus,. on energization of the coil 27, armature 12 is released and armature 72 attracted thereby opening contact 76 and closing, contact 77, also the armature 71 unlocks the armature 9. Hence the coil 5, energized through the contact 77, can attract armature 9 which in turn opens contacts 22 and closes contacts 23. The apparatus. may then be returned to the initial position by a similar sequence of operations by energizing the coil 16. According to a further modification the unlatching coil 27 and permanent magnet 32 of the relay 2 are omitted so that the armature 12 is released when the operating coil 24 is de-energized. Specifications 515,793 [Group XXX] and 765,662 are referred to.