Abstract: A power drive mechanism for a circuit breaker handle which includes a reversible electrical motor, a carriage assembly and a cooperating slide plate assembly mechanically coupled to the motor shaft. The carriage assembly includes a pivotally mounted L-shaped lever, interlocked with the circuit breaker operating handle for driving the operating handle to an on position or alternatively to an off position on command. Microswitches are located at both the on position and the off position for controlling operation of the motor. The microswitches are actuated by the slide plate assembly which, in turn, is driven by the carriage assembly. The slide plate assembly is slidably mounted with respect to the carriage assembly with one or more wave washers. The slide plate assembly provides mechanical damping for the carriage assembly to minimize damage to the microswitches.

Abstract: Briefly, the present invention relates to a molded case circuit breaker. The molded case circuit breaker includes at least one pair of separable main contacts, mounted on upper and lower contact arms. One end of the lower contact arm is formed as a U-shaped portion defining depending leg portions and a bight portion forming a reverse current loop. Disposed adjacent the lower main contact on the lower contact arm is an arc runner assembly which directs the arc resulting from a separation from the upper and lower main contacts into an arc chute to quench the arc. The arc runner assembly includes an arc runner and a support block. The arc runner may be formed from steel and is carried by the support block, disposed between depending leg portions of the lower contact arm. The support block is formed from an electrically insulating material, such as a glass polyester.

Abstract: A laminated contact assembly is formed from a number of individual contact assemblies. Each individual contact assembly includes a contact arm portion, which carries a movable main or arcing contact and a stationary conductor portion. A flexible shunt is used to connect the contact arm portion to the stationary conductor portion. Intermediate individual contact assemblies are provided with T-shaped slots for receiving square-headed fasteners. These square-headed fasteners are captured by adjacent assemblies once the laminated contact assembly is complete. By providing such an arrangement, the need to drill and tap holes in the base of the laminated contact arm assembly is obviated. Since all of the individual contact arm assemblies are fastened together, the possibility of the square-headed fasteners disposed in T-shaped slots in intermediate individual contact arm assemblies is greatly reduced.

Abstract: An electrical switching device characterized by an enclosure containing a switch operable between ON and OFF positions by a handle releasably lockable in the OFF position; the handle being disposed between the enclosure and a handle guard, the guard having an opening, the handle having a tab engaging a shoulder surface in the opening when in the OFF position; an interlock plate for releasably latching an enclosure cover in place and the plate being releasable by movement of the handle in the OFF position; and the handle being movable to the ON position only by manipulation of the interlock plate, whereby accidental movement of the handle is avoided.

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 molded case circuit breaker includes a movable upper electrical contact carried by a contact member having an end portion with an arcuate cam surface formed thereon for engaging an outwardly projecting cam surface of a leaf spring. The leaf spring is secured to and disposed around an enlarged portion of a rotatable cross-bar of the operating mechanism of the circuit breaker. The leaf spring has an outwardly protruding cam surface and is mechanically configured to provide sufficient biasing force to the end portion of the movable upper electrical contact member to enable the upper electrical contact member and upper contact to move in unison with the cross-bar during normal operation of the breaker. Upon the occurrence of a high level short circuit or fault current of sufficient magnitude, the upper electrical contact rotate member and upper and the arcuate cam surface thereof is moved against the then stationary cam surface of the leaf spring.

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: This invention provides an electric control device comprising a unique and novel auxiliary contact structure is made an integral part of the operating coil. This new arrangement greatly expands the interlocking capabilities of electric control devices without causing an increase in the device's overall size.

Abstract: An electric control apparatus with an electromechanical latch device which allows the electric control device to be momentarily energized to one operating position, mechanically latched in that position, and released to return to its initial position after momentarily energizing the latch device mechanism.