Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Tripping means
Reexamination Certificate
1999-04-28
2001-05-01
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Tripping means
C335S167000
Reexamination Certificate
active
06225881
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a thermomagnetic circuit breaker having a selective trip display.
Circuit breakers in a preformed or cast housing with thermomagnetic tripping means are well known in commercial and industrial applications. U.S. Pat. No. 3,162,739 discloses a means of this kind which has a bimetallic strip for thermal trip resulting from overload currents and a magnetic element for instantaneous trip resulting from short-circuit current surges. The tripped state is displayed by the particular position of the operating handle, as is indicated in U.S. Pat. No. 3,158,717.
A means for providing a visual display of an overload condition (reason for trip) in a thermomagnetic circuit breaker is disclosed in U.S. Pat. No. 3,883,781 and U.S. Pat. No. 5,519,561. The systems described therein use either mechanical or electrical logic information, provided by the bimetallic strip, to execute and produce a display of the overload condition. If such a device is equipped only with overload and momentary reaction elements (trip elements), a selective trip display is provided, where an instantaneous trip reaction exists when the operating handle designates the “tripped” state and the overload display system is not activated.
The increasing significance of electronic circuits as suitable devices for the display of overcurrents in electric line protective means has likewise made possible devices for distinguishing between the reasons for a trip. Printed source U.S. Pat. No. 5,485,343 describes an electronic trip unit for a circuit breaker which permits the user to determine the intensity of as well as the reason for the overcurrent condition after occurrence of the overcurrent trip. The electronic trip display for such trip information is similar to the display described in U.S. Pat. No. 4,870,531, and the control unit for such an electronic trip unit is like the trip unit described in U.S. Pat. No. 4,672,501.
In U.S. Pat. No. 3,158,717 the reason for occurrence of a disconnect condition, be it because of overload or due to a momentary overcurrent, is not indicated.
In U.S. Pat. Nos. 3,883,781 and 5,519,561, however, the devices are unable to provide a selective trip display if more than two trip elements, such as with reference to an overload, a momentary trip, a ground fault or an accessory trip (trip due to additional structural components or accessories), are provided.
The additional functions available in circuit breakers having electronic trip units, such as U.S. Pat. No. 4,870,531, however, do not always justify the additional costs for the components of electronic trip units.
Thus there is a particular need to design a thermomagnetic circuit breaker so that upon trip of the thermomagnetic circuit breaker the reason for trip is displayed in simple fashion.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the present invention, a circuit breaker comprises a circuit breaker housing having an indicator opening. A current path disposed within the circuit breaker housing connects with a protected circuit. At least one pair of separable contacts disposed within the current path connects and disconnects the protected circuit. The circuit breaker further includes an operating mechanism having a ratchet lever and an operating spring arranged for separation of the separable contacts in response to a first trip condition. External actuation of the actuation of the operating mechanism is provided by an operating handle extending through an access opening in the housing. A first trip ratchet is arranged to restrain the ratchet lever from release of the operating spring under quiescent current transferred through the current path. A second trip ratchet restrains the first trip ratchet to provide further restraint of the ratchet lever under quiescent current transferred through the current path and to release the restraint in response to the first trip condition. A first trip lever includes a first, second and third ends. The first end interacts with the second trip ratchet to remove the restraint. The second end interacts with the operating mechanism to reengage the restraint of the ratchet lever. A first trip bar, which is pivotally disposed in the circuit breaker, includes a first, second and third end. The first end releasably engages the third end of the first trip lever. The second end is selectively visible through the indicator opening. A first sensing unit interacts with the third end of the first trip bar. In response to the first trip condition, the first sensing unit pivots the first trip bar which releases the third end of the first trip lever to release the restraint to the ratchet lever. The release of the restraint separates the separable contacts and pivots the position of the second end of the first trip bar relative to the indicator opening to provide visual indication of the separation of the separable contacts.
REFERENCES:
patent: D. 367265 (1996-02-01), Yamagata et al.
patent: 2340682 (1944-02-01), Powell
patent: 2719203 (1955-09-01), Gelzheiser et al.
patent: 2937254 (1960-05-01), Ericson
patent: 3158717 (1964-11-01), Jencks et al.
patent: 3162739 (1964-12-01), Klein et al.
patent: 3197582 (1965-07-01), Norden
patent: 3205325 (1965-09-01), Archer et al.
patent: 3307002 (1967-02-01), Cooper
patent: 3517356 (1970-06-01), Hanafusa
patent: 3596219 (1971-07-01), Erickson
patent: 3631369 (1971-12-01), Menocal
patent: 3803455 (1974-04-01), Willard
patent: 3883781 (1975-05-01), Cotton
patent: 4090158 (1978-05-01), Oeda
patent: 4129762 (1978-12-01), Bruchet
patent: 4144513 (1979-03-01), Shafer et al.
patent: 4158119 (1979-06-01), Krakik
patent: 4165453 (1979-08-01), Hennemann
patent: 4166988 (1979-09-01), Ciarcia et al.
patent: 4220934 (1980-09-01), Wafer et al.
patent: 4255732 (1981-03-01), Wafer et al.
patent: 4259651 (1981-03-01), Yamat
patent: 4263492 (1981-04-01), Maier et al.
patent: 4276527 (1981-06-01), Gerbert-Gaillard et al.
patent: 4297663 (1981-10-01), Seymour et al.
patent: 4301342 (1981-11-01), Castonguay et al.
patent: 4360852 (1982-11-01), Gilmore
patent: 4368444 (1983-01-01), Preuss et al.
patent: 4375021 (1983-02-01), Pardini et al.
patent: 4375022 (1983-02-01), Daussin et al.
patent: 4376270 (1983-03-01), Staffen
patent: 4383146 (1983-05-01), Bur
patent: 4392036 (1983-07-01), Troebel et al.
patent: 4393283 (1983-07-01), Masuda
patent: 4401872 (1983-08-01), Boichot-Castagne et al.
patent: 4409573 (1983-10-01), DiMarco et al.
patent: 4435690 (1984-03-01), Link et al.
patent: 4467297 (1984-08-01), Boichot-Castagne et al.
patent: 4468645 (1984-08-01), Gerbert-Gaillard et al.
patent: 4470027 (1984-09-01), Link et al.
patent: 4479143 (1984-10-01), Watanabe et al.
patent: 4488133 (1984-12-01), McClellan et al.
patent: 4492941 (1985-01-01), Nagel
patent: 4541032 (1985-09-01), Schwab
patent: 4546224 (1985-10-01), Mostosi
patent: 4550360 (1985-10-01), Dougherty
patent: 4562419 (1985-12-01), Preuss et al.
patent: 4589052 (1986-05-01), Dougherty
patent: 4595812 (1986-06-01), Tamaru et al.
patent: 4611187 (1986-09-01), Banfi
patent: 4612430 (1986-09-01), Sloan et al.
patent: 4616198 (1986-10-01), Pardini
patent: 4622444 (1986-11-01), Kandatsu et al.
patent: 4631625 (1986-12-01), Alexander et al.
patent: 4642431 (1987-02-01), Tedesco et al.
patent: 4644438 (1987-02-01), Puccinelli et al.
patent: 4649247 (1987-03-01), Preuss et al.
patent: 4658322 (1987-04-01), Rivera
patent: 4672501 (1987-06-01), Bilac et al.
patent: 4675481 (1987-06-01), Markowski et al.
patent: 4682264 (1987-07-01), Demeyer
patent: 4689712 (1987-08-01), Demeyer
patent: 4694373 (1987-09-01), Demeyer
patent: 4710845 (1987-12-01), Demeyer
patent: 4717985 (1988-01-01), Demeyer
patent: 4733211 (1988-03-01), Castonguay et al.
patent: 4733321 (1988-03-01), Lindeperg
patent: 4764650 (1988-08-01), Bur et al.
patent: 4768007 (1988-08-01), Mertz et al.
patent: 4780786 (1988-10-01), Weynachter et al.
patent: 4831221 (1989-05-01), Yu et al.
patent: 4870531 (1989-09-01), Danek
patent: 4883931 (1989-11-01), Batteux et al.
patent: 4884047 (1989-11-01), Baginski et al.
patent: 48841
Bauer Rolf-Dieter
Felden Walter
Reichard Matthias
Thamm Christian
Cantor & Colburn LLP
Donovan Lincoln
General Electric Company
Horton Carl B.
Nguyen Triyler T.
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