GB781641A - Improvements relating to polarised electro-magnetic relays - Google Patents

Abstract

781,641. Electromagnetic relays. TELEPHONE MANUFACTURING CO., Ltd. June 9, 1955 [June 14, 1954], No. 17434/54. Class 38 (5). A polar relay comprises, Figs. 1, 2, 3, a non- magnetic frame 3 supporting in its aperture a plate armature 1 by a transverse suspension strip 2 fixed to the armature centre at 22. One end of the frame 3, together with a pair of polepieces 4 and a pair of permanent magnets 8 form a stack clamped together by a single bolt 20 passing through a frame slot 21, the interengaging faces of the members of the stack being accurately finished by grinding. The flux in the polepieces 4 produced by the control coil 6 passes across the right-hand of the armature in a path denoted by 7. The permanent magnet poles 10 have similar polarity and are situated opposite the hinge 2, the flux flowing in two parallel paths denoted by 11. The moving contact springs 14 are operated by an insulating ball 15 carried by the armature, the latter being balanced by an aperture 16. The contact spring assembly may include the features disclosed in Specifications 770,308, and 775,302. The strip 2 is fixed to the frame 3 by cross-arms 23 receiving screws 28, extensions 27 of the cross-arms resting on bosses 29, whereby selective adjustment of the screws provides a four-point adjustment for the armature. The strip 2 is strengthened by webs 25. The extensions 27 may be omitted and, instead, a coil spring may encircle each screw 28. In another modified mounting, Fig. 4, the screws are threaded into plugs 30 adjustably threaded in the frame 3. In another construction, Fig. 10, the stack clamped together by a bolt 33 includes a non-magnetic insulating bar 31, the polepieces 4 and permanent magnets 8, and flux concentrating discs 8A, the interengaging faces being accurately finished as in the first-described embodiment. The bar 31 is secured to the upper surface of one end of the frame 3 by a pair of bolts (Figs. 5-7, not shown). The plate armature 1 supported by the strip 2 is in two parts riveted together, and has slightly tapering ends, and has a three-point adjustable suspension as disclosed in Specification 781,642. According to the Provisional Specification, the permanent magnets may be constructed in accordance with Specification 715,630. Specifications 315,496, [Class 38 (v)], 559,047 and 619,546 also are referred to.