GB971509A - Electric circuit breaker - Google Patents

Abstract

971,509. Automatic circuit-breakers. MECHANICAL PRODUCTS Inc. Jan. 3, 1962, No. 279/62. Heading H2B. In a circuit-breaker of the kind having a pivoted trip lever 114 and a hot wire 136 attached at one end to the lever, the wire 136 extends at a small angle with respect to a line drawn between the pivotal axis of the lever 114 and the point of attachment of the wire to the lever so that a relatively small increase in the length of the wire will effect a relatively large angular movement of the trip lever. In the arrangement shown, the expansion of the wire 136 causes the lever 114 to turn anticlockwise under the bias of a spring 150. The lever 114 acts on a latch lever 106 and turns it clockwise to move a latch 104 away from the end 102 of a lever 40 which carries a contact 38 and is pivoted at 90 on a slide 70. A spring 92 now turns the lever 40 and a spring 84 raises the slide 70, the contacts 36, 38 being opened. To close the contacts, an operating button 50 is depressed to push down the slide 70 until the end 102 of the lever 40 passes below the latch 104. The spring 84 can now close the contacts when the button 50 is released. Manual tripping may be effected by pulling the button 50 outwardly so moving a second slide 65 relatively to the first slide 70 against the bias of a spring 63 interposed between the bent-over ends 62, 64 of the slides 70 and 65 respectively. The movement of the slide 65 causes a projection 182 on this slide to turn the latch lever 106 clockwise and so release the latch.