GB510521A - Improvements in and relating to toggle-operated electric circuit breakers - Google Patents

Abstract

510,521. Electrically-released switches. DORMAN & SMITH, Ltd., and SMALLEY, T. Jan. 31, 1938, No. 2943. [Class 38 (v)] A circuit-breaker of the kind in which the pivoted contact arm is closed by a handle and intermediate toggle mechanism, has one end of the toggle disposed in a closed slot having a narrowed portion formed by a permanent stop on one edge of the slot and a balanced stop pivoted on the opposite side, the two forming a thrust-receiving stop movement of the end of the toggle in the slot during closing. The balanced stop when moved, allows the free end of the toggle to pass beyond it and the permanent stop, and allows the toggle-end to ride over it and return to its thrusting position where it is again trapped in front of the balanced stop, by the automatic return of the latter to its stopping position. The contact-arm 5 is pivoted at 6 and provided with a slot having a recess 12 forming the permanent stop which co-operates with the roller 13 on the spring-urged bellcrank lever 14 forming the balanced stop. In order to close the breaker from the position shown, the handle 7 is rotated anticlockwise about pivot 9 and, by means of its extension 8, drives the link 10 inwards until the dead-centre position is reached. Further movement of the handle draws back the roller 11 and when it enters recess 12, the spring rotates the lever 14 anticlockwise until the stop 15 bears on the arm, thus trapping the roller 11 in the recess. Reverse rotation of the handle closes the breaker, the toggle being retained in fully-extended position by a stop. When the lever 14 is deflected, the arm 5 falls back into the open position shown. In a modification. Figs. 3, 4 (not shown), the link 10 and roller 11 are pivoted on arm 5 and the opening with recess 12 and lever 14 are provided on the extension 8, the operation being similar.