Patent GB-1484476-A (GB)
Title: Electromagnetic relay with reversible contact units
IPC: H01H50/30
Filed: 1974-08-19
Abstract: 1484476 Electromagnetic relays; contact units SQUARE D CO 19 Aug 1974 [1 Nov 1973] 36349/74 Heading H1N An electromagnetic relay, Fig. 4, comprises interrelated subassemblies of a core and coil 12, an armature and motion transmitting means 14, and a pair of contact unit supports 164, 164A which provide socket-type compartments for accommodating a plurality of detachable and reversible contact units 166, Figs. 7 and 8, whereby the relay may have normally open or closed contacts, or a mixture of both, the subassemblies being held together by screw fixings and surmounted by a cover 18. The core assembly (26) (Fig. 5, not shown) is of conventional U-shape with shading rings on each pole face and is located within a hollow moulded housing (20) backed by a mounting plate (22), the coil assembly (24) being an encapsulated moulded part having a pair of coil windings respectively around bores (86) which slip over the core legs. The armature and motion transmitting means 14, Fig. 6, includes another moulded housing 90 in which the U-shaped armature 92 is spaced away from the core in the de-energized position of the relay by two springs 96 located between the coil assembly 24 and guide members 94 which engage a member 98 positioned in the bight portion 108 of the armature. The housing 90 also includes two biased apart notched pivoted levers 100A, 100B assembled in interlinked relationship in a generally horizontal plane each bearing on the flat outer surface of the armature bight portion and having an actuating portion 136 which bears against a plurality of motion transmitters 104 which carry operating plungers 158 having tips 162 projecting through a cover 106 of the housing 90 as seen in Fig. 4. The moulded contact unit supports 164, 164A, Fig. 3, each containing a spring-loaded tool-operated operating plunger 184 accessible and visible as an indicator through openings 222, 224 in the cover 18, are assembled back-to-back and pluralities of terminal connection strips 190, 192 are outwardly directed from the side of a plurality of socket openings 172A, 172B, 172C, 172D, the openings being accessible from the front of the mounted relay, when the cover has been removed, for the insertion of the reversible contact units 166 with respective opposite ends 298, 296 abutting the plunger tips 162 as shown in Fig. 9. The contact units each comprise a twopart housing 242,244 having differently coloured ends 248, 250 visible through openings 216 in the cover 18, so that the orientation of the unit can be observed. The housing contains lateral contacts 264, engageable with the connection strips 190, 192 in the support socket containing the unit, and a movable contact assembly 284 which is slidable in the housing and carries a bridging contact 292 for engaging portions 278 of the contacts 264. Springs 290, 291 in the assembly urge seats 288, 289 against the ends of the assembly, spring 291 also urging contact 292 against a surface 308. The arrangement is such that whichever way up the unit 166 is inserted on the support, the seat 288 or 289 engages recesses 236 in the cover 18 and under pressure of the plunger tips 162 either spring 290 or 291 is compressed to provide a force urging the assembly 284 downwardly so that when the electromagnet is energized and the tips 162 are released, the assembly moves to open or close the contacts in the unit.