Movable contact structure for a circuit breaker

摘要

A circuit breaker (10) has a housing (12). A crossbar (114) is pivotally connected to the housing to pivot about an axis (117) between open and closed positions. A load contact arm (110) is pivotally connected to the crossbar (114). The load contact arm (110) is capable of pivoting about the axis (117). A cam mechanism (140) is mechanically coupled to the load contact arm (110). The cam mechanism (140) is slideably mounted within the crossbar (114) for movement between first and second positions. In the first position of the cam mechanism (140), the load contact arm (110) pivots through an angle ( beta ) about the axis, relative to the crossbar (114) between the "touch" and closed positions, and the load contact arm (110) pivots together with the crossbar (114) through an angle ( alpha ) about the axis (117) between the open and "touch" positions. (2) In the second position of the cam mechanism (140), the load contact arm (110) is free to pivot about the axis (117) through the angle alpha to the open position while the crossbar (114) is in the closed position. A biasing spring (160) applies a biasing force to bias the cam mechanism (140) towards the first position.