Patent ID: 6940374
Filing Date: 2005-09-06
Classification: H01H

Abstract:
1. An overload/open-phase tripping device for tripping a circuit breaker upon an overload and an open-phase of a main circuit, comprising: a plurality of bimetallic elements arranged in a row and corresponding to respective phases of the main circuit for generating forces upon the overload and the open-phase, a tripping lever disposed to be rotatable around a pivot for transmitting the forces to a switching mechanism of the circuit breaker, and a differential shifter mechanism disposed between the bimetallic elements and the tripping lever for transmitting the forces to the tripping lever, said differential shifter mechanism including a push shifter disposed on one side of each of the bimetallic elements to be movable in a direction of deformation of the bimetallic elements and having first operation ends contacting the respective bimetallic elements, a pull shifter disposed on the other side of each of the bimetallic elements to be movable in a deformation returning direction of the bimetallic elements and having second operation ends contacting the respective bimetallic elements; and a differential lever disposed between the push shifter and the pull shifter for applying the forces to the tripping lever, said differential lever being rotationally connected to the pull shifter and slidably rotationally connected to the push shifter, said differential lever having a first action end for applying the force to the tripping lever upon the overload and a second action end for applying the force to the tripping lever upon the open-phase.