Square D Company

Daniel R Schiefen

John M Winter

Clark L Oster

Paul J Rustebakke

A circuit breaker for breaking current conduction between line and load connectors in response to tripping of a bimetallic thermal element as a result of an over-current condition is disclosed. According to the invention, a trip crossbar is permitted to translate as well as rotate to relieve stress on the thermal element.

Trip crossbar translation to prevent bimetal overstressing in a circuit

A circuit breaker having positive contact indication. Upon the circuit breaker tripping, the operating mechanism components unlatch, moving the cradle, upper link and lower link upwards and opening the contacts. Upon the circuit breaker being manually opened, no operating mechanism components move except the upper link and lower link which causes the contacts to open. Upon the occurrence of locked contacts and the operating mechanism receiving a trip signal, the operating mechanism components unlatch but move only slightly since the contacts cannot open. A shuttle, pivotally mounted on the cradle, moves upward slightly to catch its tail on a flipper spring. The shuttle rotates slightly to meet a tab positioned on the handle arm and to block and opening movement of the operating handle.

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Cedar Rapids, IA, United States of America

Daniel R Schiefen