Low-voltage circuit breaker

Abstract

A low-voltage circuit breaker, including: at least one fixed contact, for each pole, which is electrically connected to a terminal for connection to an electric circuit and a corresponding moving contact which is associable/separable with respect to the fixed contact by means of a rotation of the moving contact; an arc chamber positioned in correspondence of the fixed contact; a rotating contact supporting shaft common to all poles, which is functionally connected to an actuation mechanism of the circuit breaker, the actuation mechanism including a kinematic system operatively connected to an actuation lever for opening/closing operations and provided with opening springs and a tripping shaft for releasing the kinematic system and allowing its movement from a closed to an open position. The low-voltage circuit breaker includes for each pole a quick acting trip device including a plunger inserted in a first channel connected to an arc chamber of the corresponding pole, the first channel being positioned proximate to the at least one fixed contact with its longitudinal axis perpendicular to the axis of the rotating contact supporting shaft, the plunger having a first operative surface subjected to the pressure of the arc chamber and a second operative surface, the quick acting trip device further includes a trip lever having a first portion cooperating with the tripping shaft and a second portion cooperating with the second operative surface of the plunger.

Dependencies are inferred from the claim text.