Patent ID: 6870112
Filing Date: 2005-03-22
Classification: H01H

Abstract:
1. A low-voltage circuit breaker, comprising: at least one first fixed contact, which is electrically connected to a terminal for connection to an electric circuit; a rotating moving contact, which comprises a central body from which at least one first arm protrudes, an active surface being provided at the end of said first arm, said active surface being associable/separable with respect to said fixed contact by means of a rotation of said moving contact, at least one first cam-like surface being formed on said central body; a rotating contact supporting shaft, which is functionally connected to an actuation mechanism of the circuit breaker and is provided with a seat that accommodates the central body of the moving contact so that the first arm protrudes externally from said seat, at least one first spring and one second spring being furthermore arranged in said contact supporting shaft and being suitable to ensure, when the circuit breaker is closed, an adequate contact pressure between said active surface and the fixed contact; characterized in that a first pivot is fixed to said contact supporting shaft and is coupled to a hole formed in said central body, engagement means and at least one second pivot being furthermore arranged on said shaft on mutually opposite sides with respect to the first pivot, said second pivot being movable with respect to the shaft and to the moving contact, said first and second springs being furthermore anchored to the second pivot and to the engagement means and being arranged along two opposite sides of the arm of the moving contact, said second pivot interacting functionally with said first cam-like surface so as to generate a mechanical moment that matches the direction of rotation of the moving contact during at least one portion of the step for separation of the active surface from the fixed contact in a short-circuit condition.