Abstract: The breaker mechanism for power circuit breakers is the energy storage link between the handle and the contact systems. Known breaker mechanisms are generally too expensive to manufacture. When contact welding occurs, there is also the risk that, in spite of the tripping of the breaker mechanism, the contact system will not open. The new breaker mechanism reliably opens the contact system and consists of fewer and technologically simpler individual parts. It is inserted between two symmetrical breaker plates held in a die cast housing, and in which a connecting piece is mounted. Two toggle levers are connected at a distance from one another by means of a connecting shaft engaged in crossbar cam slots. A toggle lever spring is engaged between the connecting piece and the connecting shaft. A bracing lever which can be driven by the connecting piece is friction locked in the breaker plates, and the toggle levers in the bracing lever.