Siemens Energy & Automation, Inc.

Siemens-allis, Inc.

Rex J McColloch

Stephen D Cella

Bernard DiMarco

Brian Timothy McCoy

William A King

William E May

Lawrence G Navarre

A circuit breaker mechanism has a contact arm (56) forming a portion of an interruptable load current path through the circuit breaker and mounted with respect to a pivot (110) for swinging motion to break the current path. A spring-loaded, over-center operating mechanism includes a toggle mechanism having an upper toggle (74) and a lower toggle (122) coupled by a spring pin (128) to form a toggle joint about which the toggles can relatively pivot. The spring pin has a circular groove (128b) at which it operatively connects to the toggle joint, and a circular surface (128a) adjacent the groove is disposed in the path of travel of the contact arm as the contact arm swings to break the current path. A V-shaped notch (56a, 56b) in the contact arm, acts between the toggle joint and the contact arm to locate the toggle joint radially of the contact arm pivot and thereby cause the toggle joint to be displaced by the swinging contact arm along an arc such that a principal component of the contact arm force is directed in a sense that fully, or at least approximately, maximizes the effect of the swinging contact arm force on the toggle mechanism.

Circuit breaker with improved trip mechanism

A current limiting circuit breaker including novel clutch arrangements between the contact arms of the circuit breaker and the crossbar. The clutch arrangements include cam surfaces formed on the crossbar from plastic and a cam follower attached to each contact arm. A cam surface is located on each side of each contact arm and each surface may be formed integrally with an insulating barrier. To reduce wear on the cam surfaces, each cam follower includes a roller which contacts the respective cam surface. The cam surfaces are configured to permit the contact arms to blow open under unacceptable fault conditions even though the crossbar remains stationary.

Circuit breaker with molded cam surfaces

A current limiting circuit breaker including a novel spring arrangement between the contact arms of the circuit breaker and the crossbar. The spring arrangement includes a single spring which holds the cam follower attached to each associated contact arm in contact with cam surfaces of the crossbar. The longitudinal axis of the spring is located within a plane passing through the longitudinal axis of the contact arm, wherein the plane is also perpendicular to the rotational axis of the contact arm. The cam surfaces and spring are configured to permit the contact arm to blow open under unacceptable fault conditions even though the crossbar remains stationary.

Circuit breaker with improved contact arm follower spring arrangement

A multi-phase circuit breaker including novel crossbar for opening and closing the circuit breaker contact arms. The crossbar is a one-piece plastic component molded to include an operating arm, insulating barriers for separating the contact arms of each phase, and the cam surfaces which interact with the cam followers of the contact arms. The operating arm is linked to the operating mechanism of the circuit breaker so that operation of the mechanism will pivot the crossbar which pivots the contact arms between their open and closed positions.

Circuit breaker with one-piece crossbar including an integrally molded

A molded case circuit breaker has control terminals mounted on the front of the breaker and accessible from the front. A transparent plexiglass cover is positioned over the terminals to prevent inadvertent contact with the terminals and an opening is provided in the side of the casing for the egress of the control wires. With the control terminals on the front of the circuit breaker, an inspection can be performed without disconnecting power from the breaker.

Growing community of inventors

Snellville, GA, United States of America

Rex J McColloch