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Abstract

The present invention relates generally to a mechanism of a contact system for circuit breakers. More particularly, the invention encompasses a mechanism for a rotary double-break contact system, which enables a direct transfer of torque from stored energy components, such as, springs, to the contact arm in the ON-position (contacts closed) without using intermediate cam surface. The mechanism described in the invention also ensures reliable locking of the contact arm in the blow-off position using stationary means that are integral with or fixed to a crossbar module. This invention enables to achieve significant reduction or even to eliminate friction at certain critical interfaces between the contact mechanism components, thus, reducing or potentially eliminating hysteresis, and improving performance consistency, and also eliminating mechanism performance dependency on wear level and condition of an intermediate cam surface. An additional feature of this invention is a reduction of a loss of contact torque/force during over-travel in the ON position when the fixed and/or moveable contacts erode. Configurations described in this invention may also feature physical protection for the moving components of the contact mechanism assembly from flying particles resulting from short circuit shots.

First Claim