GB625804A - Improvements in and relating to electromagnetic switches - Google Patents

Abstract

625,804. Electromagnetic switches. BRITISH THOMSON-HOUSTON CO., Ltd. April 3, 1945, No. 8214. Convention date, April 4, 1944. [Class 38(v)] A contactor is operated by abutting plunger armatures 26, 27 pivotally connected to arms of bell-crank levers 28, 29, the other arms of which have a pin and slot connection 32, one of these latter arms being provided with a toothed segment 33 engaging a gear 34 coupled to a crank 36 actuating a rotatable cross-bar 17 carrying moving bridge contacts 21, 22, 23. The crank 36 rotates through 180 degrees from the "on" position, Fig. 1, to the "off" position to which the levers 28, 29 are biassed by springs 39, 40 on their fixed pivots 30, 31; these positions being dead-centre crank positions to render the contactor shockproof. The cross-bar 17, pivoted at 10, 11 has a U-shaped member 38 welded to it which has a swivel connecting with a link 37 pivoted to the crank 36. The contacts 21, 22, 23 are resiliently mounted on a cross-bar 20 carrying guide-pins at its ends and pivoted at 18, 19, to arms 15, 16 of the cross-bar 17. The stationary contacts 52 are mounted in insulating cups 53 carried on insulating blocks 51 and are connected to terminal plates 57. An operating coil 24 has shock proof mounting within the magnet frame 45 between insulating pieces 73, 74 having four projections 75, 76 engaging metal members 77 and is pressed to the right by two springs 83. Guides for the armatures 26, 27 are secured by screws 80. The lever 29 carries an "off" position stop 40a, and by a second pin-and-slot connection actuates an auxiliary switch arm 61, which bridges contacts 66, 67 when the contactor is "off." The pivots 30, 31 and the shaft to which the crank 36 and the gear 34 are secured, are all carried by a bracket 42.