GB485811A - Improvements in or relating to latching mechanisms for electric circuit interrupters - Google Patents

Abstract

485,811. Automatic circuit-breakers. WESTINGHOUSE ELECTRIC & MANUFACTURING CO. May 5, 1937, No. 12815. Convention date, May 14, 1936. [Class 38 (v)] A quick-acting latching member for a circuitbreaker having an operating mechanism biassed to open-circuit position for effecting a switching operation comprises a member for releasably engaging a trip-free element of the operating mechanism to retain it in a predetermined position, a spring-biassed arm disposed for co-operative engagement with the said member and effecting a partial balancing of the reactive pressures from the biassed operating mechanism, and a latch for locking the arm to lock the said member thereby to retain the trip-free element in the predetermined position. The contact-operating rod 16 is pivoted at 20 to a floating member 18 comprising a pair of levers interconnected by a bar 52 and carrying between them a trip-free bar or roller 22. The member 18 nests within, and is pivoted at 26 to, a pair of levers 24 which are interconnected by a bar 54, pivoted to the frame at 28, and connected by link 46 to a closing magnet. When a latch 34 engaging the pivot 26 is deflected, a spring 30 rotates levers 24 clockwise about pivot 28. In the closed position, the roller 22 is in alignment with the pivots 28 and is engaged by a spring-loaded member 56 pivoted at 58. Member 56 is retained in engagement with roller 22 by an arm 66 which is pivoted at 68 and urged by springs 74, 76 so that a notch 70 thereon engages a surface 72 on member 56. The springs 74, 76 are not strong enough to retain 66 and 56 in engaging position, and accordingly they are latched by a part 80 on a bell-crank 82, which is pivoted at 84 and biassed by the spring 76. The latch 80 is trippable by the solenoid-plunger 89, which not only deflects 80 clear of arm 66, but brings a part 88 on the latch-member against a part 90 on the arm 66, so positively removing the latter from engagement with member 56, and permitting the opening force on the contacts to deflect member 56. During the opening movement of 18, a member 36 thereon engages a member 38 on the latch 34, so releasing the levers 24. Spring 30 accordingly rotates levers 24 to the dotted position, and in doing so restores the lever 18 and roller 22 to the latched position. Energization of the closing magnet then rotates 18, 24 counterclockwise about pivot 28 so that the parts are re-latched at 26, 34. The roller 22 is guided in its movement to latched position by the surface 103 of a spring- controlled member 104 pivoted at 106. During the trip movement, the spring 110 overcomes spring 60 and forces the member 56 against a stop 112, so preventing member 56 from engaging the roller 22. The plunger 89 is also adapted to be manually raised by means of a spring- controlled trip lever 92 which actuates the plunger by means of an intermediate member 98 resting on a guide-bolt 100 for the handle.