Circuit breaker cover with screw locating feature
AssigneeGeneral Electric Company
InventorsJavier Ignacio Larranaga, Joseph Criniti, Thomas Randolph Campbell
Life of this patent
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Abstract
A molded circuit breaker cover for providing access to a calibration screw of a thermal trip unit is disclosed. The cover includes an exterior surface having an opening disposed therein and a locator extending from an underside of the cover. The locator includes a channel surface defining a channel continuous with the opening wherein the locator captures the calibration screw and aligns the calibration screw with the opening. Locator significantly increase the calibration yield of multi-pole circuit breakers by decreasing misalignment of the calibration screws during assembly of the circuit breaker.
Claims27
A molded circuit breaker cover for providing access to a calibration screw of a thermal trip unit, said cover comprising:
- an exterior surface having an opening disposed therein;
- an underside, said opening passing though said exterior surface and said underside;
- a locator extending from said underside of said cover, said locator includes:
- a passage surface defining a passageway, said passageway extending from said opening;
- a channel surface defining a channel, said channel extending from said passageway and continuous through said locator;
- wherein said locator aligns said calibration screw with said opening;
- and
- wherein said locator provides access to said calibration screw from said opening through said passageway and said channel.
A circuit breaker comprising:
- a pair of electrical contacts;
- a trip unit configured to separate said pair of electrical contacts, said trip unit including:
- an adjusting bar configured to interact with said trip unit, said adjusting bar includes a calibration screw threadingly engaged thereto;
- and
- a molded case having a cover, said cover includes:
- an exterior surface having an opening disposed therein;
- an underside, said opening passing though said exterior surface and said underside;
- a locator extending from said underside of said cover, said locator includes:
- a passage surface defining a passageway, said passageway extending from said opening;
- a channel surface defining a channel, said channel extending from said passageway and continuous through said locator;
- wherein said locator aligns said calibration screw with said opening;
- and
- wherein said locator provides access to said calibration screw from said opening through said passageway and said channel.
A process of calibration for a circuit breaker having a bimetal within a case for sensing current and a trip lever which causes actuation of a latching mechanism to interrupt current flow, the process comprising:
- providing an adjusting bar having an arm including an aperture for receiving and holding a calibration screw, said arm being proximate to the bimetal and having a first end and a second end;
- engaging said calibration screw within said aperture;
- aligning said calibration screw with an opening in the case;
- inserting a tool within said aperture of said case;
- and
- calibrating said calibration screw by adjusting said calibration screw a predetermined distance from said bimetal.
A method of calibrating a circuit breaker with a circuit breaker cover in place on said circuit breaker, said method comprising:
- inserting a calibration tool into an opening of said circuit breaker cover and into a locator;
- extending said calibration tool through a passageway of said locator;
- engaging said calibration tool with a first end of said calibration screw;
- rotating said calibration screw with said calibration tool in a first rotational direction until a second end of said calibration screw makes contact with a bimetal;
- and
- rotating said calibration screw with said calibration tool in a second rotational direction causing second end of said calibration screw to be retracted from engagement with said bimetal, said calibration screw retracted from engagement with said bimetal a predetermined distance.
Dependencies are inferred from the claim text.