GB730978A - Improvements in automatic electric circuit breakers - Google Patents

Abstract

730,978. Automatic circuit-breakers. ETABLISSEMENTS LABINAL. Sept. 1, 1952 [Feb. 6, 1952], No. 21929/52. Class 38 (5). A circuit-breaker has a contact-carrying lever 1 biased by a spring R 1 towards its open position, Fig. 2, but normally held in its closed position, Fig. 5, by a catch lever 3 which may be moved from its holding position by the thrust exerted on it by the lever 1 when a locking lever 2 is moved aside under overload conditions. The lever 2 is moved out of engagement with the lever 3 against the bias of a spring R2 when it is rotated about a fixed pivot 02 by an overload coil 20 acting on the end 9 of the lever 2 or by a bimetallic element 6 acting on a projection 10 of the lever 2. To close the circuit-breaker, a push-button 4 is depressed causing a projection 16 to engage the lever 1 which is turned about its pivot O1 The free end of the lever 1 engages the lower edge of a notch 13 in the lever 3 and turns the lever 3 clockwise about its fixed pivot 03 out of engagement with the upper face of the lever 2 so allowing the spring R2 to turn the lever 2 into its locking position which is defined by an adjustable stop 8. The circuit remains open whilst this resetting is effected, as before the lever 1 has been moved sufficiently for the contact C, carried by it, to bridge the " fixed " contacts C1, C2, a member 24 on the push-button 4 depresses the contact C2 against the bias of a spring R3. When the push-button is released, the free end of the lever 1 engages the upper edge of the notch 13 and turns the lever 3 until it abuts the end 11 of lever 2. The lever 1 is now retained set and the spring R3 moves the contact C2 into engagement with the contact C, the contacts Cl, C, C2 being closed. Manual tripping may be effected by pulling the button 4 so that a member 18, Fig. 2, carried by the button turns the lever 2 about its pivot to release the lever 3.