GB819697A - Improvements in operating mechanism for an electric circuit breaker - Google Patents

Abstract

819,697. Automatic circuit breakers. GENERAL ELECTRIC CO. Oct. 17, 1957 [Oct. 18, 1956], No. 32463/57. Class 38 (5). A circuit-breaker operating mechanism has an over-centre closing and opening spring 50, one end of which is attached to the centre pin 23 of links 21, 22, and the other to a pin 51 on the operating member 52 pivoted to the frame 31 at 53. The link 21 is connected to the contact arm 12 and the link 22 has an end pin 26 movable in a slot 28 in the frame 31. As shown in Fig. 1 a prop 36 is biased by a spring 38 to hold a latch 32 so that it retains the pin 26 at the bottom of the slot 28, and the spring 50 biases the link 22 against a stop 55 on the member 52, to hold the contacts closed, and also biases the member 52 against a fixed stop 29. Energization of a trip coil 43 or manual operation of a push button 42 removes the prop 36 so that the force of the biasing spring 50 and the contact throwoff forces cause the pin 26 to push aside the latch 32 and move up the slot 28 until the pin 26 has passed across the axis of the spring 50 and reached the end of the slot 28. The link 22 then pivots about the pin 26 until the spring axis has passed the pivot 53 so that the member 52 rotates away from the stop 29 and its cam face 60 engages the pin 26 and moves it down the slot 28 so that the latch 32 can reset, Fig. 4. To close the breaker a handle 68 is turned so that a roller 71 lifts the pin 51 to change the spring and move its axis above the pin 26, when it rotates the link 22 to the Fig. 1 position and during this movement the axis also passes the pivot 53 so that the member 52 is also restored to its Fig. 1 position. The mechanism is " trip free " since even if the handle 68 is held the contacts can reach the fully-open state.