Abstract: A crossbar spanning the poles of a multiple pole circuit breaker. The crossbar is formed from a structural member such as beam having an I-shaped cross-section, wherein an insulating material such as plastic is molded to the beam. The shape of the structural member is such that it provides a high strength to weight ratio. The plastic is molded such that it includes means for inhibiting arcing between the poles of the circuit breaker.

Abstract: A circuit breaker characterized by a ratchet mechanism for manual or electrical charging system and comprising a pair of separable contacts coupled with a rechargeable spring to close the contacts. The spring is indirectly connected to a drive shaft on which a ratchet wheel is fixedly mounted for rotation of the shaft in one direction. A drive wheel is rotatably mounted on the shaft for rotating the ratchet wheel and a brake wheel is mounted on the shaft for preventing rotation of the shaft in the other direction. Rotating means are provided for rotating the drive shaft.

Abstract: A circuit breaker having means for varying the thermal rating characterized by a circuit breaker mechanism including a releasable cradle for automatically tripping contacts to an open position in response to overload current conditions. A trip bar movable in response to movement of a bimetal element and the tie bar including a movably mounted member having an inclined surface for adjusting the spacing between the bimetal element and the movable member.

Abstract: A circuit breaker characterized by a movable contact on a contact-carrying arm movable between open and closed positions of a stationary contact mounted on one leg of a U-shaped conductor with another leg secured to the circuit breaker housing, a U-shaped brace between the legs and having a first support supporting and insulated from the other leg and having second supports on opposite sides of the one leg for retaining it against opposing repulsion magnetic forces due to current overloads.

Abstract: A reverse loop circuit breaker characterized by a movable contact mounted on a contact-carrying arm movable between open and closed positions of a stationary contact that is mounted on one leg of a U-shaped conductor with another leg secured to the circuit breaker housing, an insulating block between the legs and including a pair of separable block portions having oppositely facing grooves for receiving edge portions of at least one leg to restrain its deflection, and means for securing the block portions together.

Abstract: A circuit breaker with an arc gas vent baffle characterized by a molded insulating housing containing circuit breaker and an arc quenching chamber, the housing having walls forming a compartment containing a terminal, the walls having spaced vent openings communicating with the compartment one of which openings is covered with a baffle to turn aside the flow of gases, and the baffle being yieldably mounted to permit access through the opening from the outside of the housing.

Abstract: A circuit breaker with arc chamber vent characterized by a molded insulating housing containing circuit breaker means and an arc quenching chamber, the housing having wall means forming a compartment containing a terminal, and the wall means having gas vent opening communicating between the chamber and the compartment and a tubular wall surrounding the terminal for preventing any arc gases exhausting from the chamber into the compartment from causing electrical breakdown between the terminal and any proximate conductor.

Abstract: An electric circuit breaker with high interrupting capacity characterized by a multi-phase circuit breaker including a crossbar rotatable on its longitudinal axis and having an enlarged portion; a contact carrying arm pivotally mounted on the enlarged portion in response to an overload current at a positions paced from the axis; and a spring biased retainer contacting the arm for yieldingly retaining the arm in a contact closed position below a predetermined current rating.

Abstract: A molded case circuit breaker includes an improved system for venting gaseous arc products from the interior of the molded case to the exterior thereof and for preventing the ingress of environmental contaminants. At least one slot is formed through the molded case and a one-way, resilient valve is disposed within the slot.

Abstract: A molded case circuit breaker includes an elongated intermediate latch lever disposed between and in engagement with an intermediate latch plate and a trip bar. The intermediate latch lever is pivotable about a pivot axis and includes a first elongated portion between the latch plate and the pivot axis of a length substantially less than the length of a second elongated portion between the pivot axis and the trip bar. The intermediate latch lever so configured reduces the force required and the amount of travel of the trip bar required to effect a trip operation.

Abstract: A molded case circuit breaker includes an improved system for internally venting gaseous arc products to control the internal gas pressure increase and expansion during an arc interruption. The system includes a first gas expansion chamber disposed proximate to a stationary electrical contact of a pair of separable electrical contacts of the circuit breaker and a second gas expansion chamber disposed proximate to an electrically insulating arc chute barrier that is positioned at an end of an elongated arc chute remote from said stationary electrical contact. The arc chute barrier and the stationary electrical contact are physically configured to effect the rapid internal venting of gaseous arc products to the first and second chambers.

Abstract: A molded case circuit breaker includes an energy or shock absorbing member for assisting in stopping the movable electrical contacts and for preventing severe damage to a movable contact arm or to the molded case of the circuit breaker. The energy absorbing member is secured to an electrically insulating arc chute barrier and is disposed between the movable contact arm and a fixed mechanical stop for absorbing energy due to the rapid movement of the movable contact arm, especially upon a trip operation due to a high level fault current condition.