US 5,517,164 AGranted

Molded case circuit breaker having movable contact finger releasably locked to an operating mechanism

AssigneeEaton Corporation

InventorsWalter M. Zoller, Donald A. Link, Michael R. Larsen, David S. Hunter, Edward L. Wellner, Peter J. Theisen

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Abstract

A subframe is coaxially pivotally mounted with a movable frame of the operating mechanism of a molded case circuit breaker and is locked to the frame by a bell crank pawl which is pivotally mounted on the subframe. A leaf spring assembly rigidly attached to the subframe overlies the movable contact finger to engage the same in the circuit ON condition of the circuit breaker to provide desired contact force. The bell crank pawl is released upon an incrementally small amount of initial movement of the movable contact arm in response to blow-open magnetic repulsion forces to release the movable contact finger for pivotal opening movement relative to the movable frame of the circuit breaker operating mechanism.

Claims16

Dependent claims

In a molded case circuit breaker including:

a molded insulating case having a handle opening;
a stationary contact mounted in said case;
a conductor mounted in said case;
a movable contact finger pivotally mounted in said case for movement into and out of engagement with said stationary contact, said finger being conductively connected to said conductor;
and
an operating mechanism disposed in said case for moving said movable contact finger into and out of engagement with said stationary contact, said operating mechanism including:
an operating handle pivotally mounted in said case and extending through said handle opening;
a movable frame pivotally mounted in said case;
means connecting said movable contact finger to said movable frame for movement therewith;
a collapsible toggle linkage having one end connected to said frame;
a latching mechanism statically positioning an other end of said toggle linkage in a latched condition of said latching mechanism;
and
resilient drive means connecting said operating handle and said toggle linkage for manually effecting movement of said movable contact finger with said latching mechanism in said latched condition, said resilient drive means effecting collapse of said toggle linkage in a released condition of said latching mechanism for effecting movement of said movable contact finger out of engagement with said stationary contact;
characterized by said means connecting said movable contact finger to said movable frame comprising:
a subframe pivotally mounted in said case coaxially with said movable frame;
a pawl pivotally mounted on said subframe;
a notch on said movable frame engaged by said pawl for locking said subframe to said movable frame;
means biasing said pawl into engagement with said notch on said movable frame;
spring means carried by said subframe biasing said movable contact finger firmly against said stationary contact in an engaged position of said finger and said stationary contact;
said movable contact finger being movable away from engagement with said stationary contact by repelling magnetic forces generated by high currents in said contactor, said finger engaging said pawl upon initial movement of said finger in response to said magnetic forces, pivoting said pawl against said biasing means for releasing said pawl from said notch, thereby releasing said subframe and said movable contact finger for movement relative to said movable frame and said operating mechanism.

17 more elements

Releasable lock means for securing a movable contact finger to an operating mechanism of a molded case circuit breaker comprising:

a movable frame of said operating mechanism mounted for pivotal movement in a molded case of said circuit breaker;
a movable contact finger mounted for pivotal movement in said molded case substantially coaxial with said movable frame, said contact finger having pivot means permitting limited movement normal to an axis of rotation;
a subframe mounted for pivotal movement in said molded case substantially coaxial with said movable frame, said subframe extending along said movable contact finger;
spring means carried by said subframe and engaging said movable contact finger biasing said finger toward an engaged position with a stationary contact of said circuit breaker;
said releasable lock means comprising a pawl pivotally mounted on said subframe and means on said movable frame engaged by said pawl for securing said subframe and said movable frame together for substantially unitary rotational movement of said movable frame, subframe and movable contact finger;
and
means on said pawl engaged by said movable contact finger upon initial blow-open movement of said contact finger from an engaged position with said stationary contact for releasing said pawl from engagement with said movable frame, thereby affording rotational movement of said subframe and said movable contact finger relative to said frame.

4 more elements

Dependencies are inferred from the claim text.