GB604272A - Improvements in and relating to electro-magnetic switches - Google Patents

Abstract

604,272. Two-part couplings with switches. BRITISH THOMSON-HOUSTON CO., Ltd. Oct 20, 1943, No. 17237. Convention date, Oct. 24, 1942. [Class 38 (i)] [Also in Group XXXVII] An electromagneticallyoperated switch has its moving contacts carried in a block removably attached to a base carrying the circuit terminals, the base and block having co-operating contacts in the magnet circuit so arranged that this circuit is opened to release the main switch contacts when the block is being detached from the base. The moving contacts 12, 19 of the main and magnet circuits respectively are mounted independently on a slide 15 in the block 33 and the slide biassed by springs 34 to circuit opening position. The fixed main switch contacts are integral with coupling contacts 35, the enlarged ends of which pass through keyhole slots 39 in the base member 26 into engagement with terminal contacts 36, 37. As the block is moved downwards, the spring- pressed contacts 19 of the magnet circuit engage contacts 20, 21 on the base, and projections 151 on the slide 15 drop behind the forked end of a lever 29 pivoted at 30 and connected to the armature 18 of the magnet 16. Remote start and stop switches, respectively in parallel and in series with the switch 19 ... 21, serve first to energize the magnet circuit which is then maintained by closure of the switch 19 ... 21 until the stop-switch is opened. Upward movement of the block 33 disengages the contacts 20, 21, so opening the magnet circuit and allowing the springs 34 to move the slide 15 to open the main circuit ; it also disengages the slide 15 from the lever so that removal of the block is not prevented by faulty actuating mechanism. The switch is housed in a casing with hinged cover, after opening which the block 33 may be withdrawn.