Patent ID: 9697975
Date: 2017-07-04
CPC Classifications: H01H

Claim:
1. A circuit breaker comprising: an arc chute; a pivotable handle; a moveable contact arm, the contact arm having first and second cooperating arm members pivotably attached together, wherein the second arm member can move inward, outward and up and down relative to the first arm member, the first arm member having a first end portion attached to the pivotable handle and having a longitudinally spaced apart second end portion attached to the second arm member, the second arm member comprising a free end portion with first and second spaced apart electrical contacts, and wherein, with the handle oriented above the moveable contact arm, the first and second electrical contacts of the second arm member reside inside or adjacent and above the arc chute, with the second electrical contact below the first electrical contact; and a mechanism spring having an inwardly extending end portion attached to the first arm member at a location that is spaced apart from the second end portion of the first arm member that is attached to the second arm member, wherein the second arm member is configured to translate the first and second electrical contacts in a rocking action so that the first electrical contact moves away from a first stationary contact after the second electrical contact engages a second stationary contact immediately prior to an arcing event, wherein, with the handle oriented to be above the moveable contact arm, the first electrical contact is held by the second arm member above the second electrical contact facing the first stationary contact and the second electrical contact is held by the second arm member facing the second stationary contact, wherein, when a contact surface of the first electrical contact is in physical contact with the first stationary contact or a contact surface of the second electrical contact is in physical contact with the second stationary contact, planes drawn parallel to the contact surface of the first electrical contact and the contact surface of the second electrical contact intersect at a location between the first and second electrical contacts of the second arm member, wherein the second arm member has a shape that places the free end of the second arm member a distance forward of the second end portion of the first arm member, and wherein, in operation, (i) the second arm member moves relative to the first arm member to position the first electrical contact surface forward of the second electrical contact to contact the first stationary contact in an ON position of the circuit breaker for a first electrical contact only contact position and (ii) the second arm member moves relative to the first arm member to position the second electrical contact surface forward of the first electrical contact to contact the second stationary contact for a second electrical contact only contact position when the contact arm rotates toward an OFF position to thereby direct arcs across only the second electrical contact.