Abstract: A pivot joint for a movable contact arm assembly and a circuit breaker having an operating mechanism coupled to a line terminal, a trip mechanism and a load terminal with the load terminal coupled to a pivot mounting member. The pivot joint comprises a recess in a first sidewall of the contact arm with the recess co-axial with a mounting hole in the contact arm. A second recess is provided in a second sidewall of the contact arm with the second recess co-axial with the second mounting hole in the contact arm. The first and second recesses are co-axial with each other. A shaped washer, configured to fit in each of the first and second recesses is provided and maintained in position by a mounting axle configured to engage each shaped washer, each mounting hole and the pivot mounting member. The contact arm is then free to pivot about the mounting axle. A spring, with the spring configured to engage both ends of the mounting axle urge the contact arm against each shaped washer thereby completing the pivot joint.

Abstract: A pivot joint for a movable contact arm assembly and a circuit breaker having an operating mechanism coupled to a line terminal, a trip mechanism and a load terminal with the load terminal coupled to a pivot mounting member. The pivot joint comprises a recess in a first sidewall of the contact arm with the recess co-axial with a mounting hole in the contact arm. A second recess is provided in a second sidewall of the contact arm with the second recess co-axial with the second mounting hole in the contact arm. The first and second recesses are co-axial with each other. A shaped washer, configured to fit in each of the first and second recesses is provided and maintained in position by a mounting axle configured to engage each shaped washer, each mounting hole and the pivot mounting member. The contact arm is then free to pivot about the mounting axle. A spring, with the spring configured to engage both ends of the mounting axle urge the contact arm against each shaped washer thereby completing the pivot joint.

Abstract: A circuit breaker including a contact operating mechanism configured to prevent the switch handle of the circuit breaker from being placed in an OFF position when the contacts are not separable. In addition to the switch handle, the mechanism is operable with a tripping circuit which actuates the mechanism to urge the contacts apart when the current flowing through the circuit breaker exceeds the preset limits of the circuit breaker. When the contacts are not separable and the tripping circuit actuates the mechanism, the operating handle is restricted from being placed in the OFF position, thereby avoiding the possibility of indicating an incorrect position of the contacts.

Abstract: The following specification describes a magnetic assembly for use in controlling the main contacts of a circuit breaker. The magnetic assembly includes a yoke, an armature for attraction to the yoke to move an operating lever and a pivotable adjustment arm. The lever operates the trip crossbar, which opens the main contacts and is in turn pivotably carried by the adjustment arm. One end of the operating lever is held against longitudinal movement relative the trip crossbar, when the adjustment arm is pivoted to calibrate the circuit breaker. The lever therefore pivots on the adjustment arm to move the armature towards or from the yoke to control the armature air gap without altering the lever travel distance to the crossbar. The armature is also mounted on the lever for relatively linear movement in relationship to the yoke.