Circuit breaker with auxiliary tripping unit

Claim 1

In a two-pole excess-current protective circuit breaker including contacts having open and closed positions; manually engageable means operatively connected with said contacts for manually opening and closing the contacts; latching means having a normal position in which operation of said manually engageable means remains unimpeded; said latching means having a tripped position for opening and maintaining open said contacts irrespective of the position of said manually engageable means and bimetal means operatively connected with said latching means; said bimetal means having a normal state allowing said latching means to assume said normal position and a heat-caused deformed state in which said bimetal means displaces said latching means into, and maintains said latching means in said tripped position; said circuit breaker further including a first housing accommodating said movable contacts, said manually engageable means, said latching means and said bimetal means; the improvement comprising in combination: (a) a pivotally supported tripping lever having first and second legs and forming part of said latching means; said bimetal means being operatively connected with said first leg; (b) an electromagnetically operated auxiliary tripping unit including (1) a second housing; (2) a solenoid accommodated in said second housing and having an energized state and a de-energized state; (3) a plunger displaceably supported in said second housing and cooperating with said first leg of said tripping lever; said plunger having an advanced position in which the plunger pushes said tripping lever for setting said latching means into the tripping position; said plunger further having a withdrawn position in which the plunger allows said tripping lever to move for setting said latching means into the normal position; said solenoid, when in said energized state, moving said plunger into and maintaining said plunger in one of the plunger positions; (4) a spring means accommodated in said second housing and being operatively connected to said plunger for moving said plunger into, and maintaining said plunger in the other of the plunger positions when said solenoid is in a de-energized state; (c) mounting means for supporting said second housing on said first housing externally thereof; (d) electric connecting means carried on said first and second housings; said electric connecting means being coupled to one another for electrically connecting said solenoid to the circuit breaker; and (e) means defining an opening in said first housing; said opening being in alignment with said latching means for providing passage of said plunger into said first housing for cooperation with said first leg of said tripping lever.