High-voltage switches with arc preventing or extinguishing devic – Arc preventing or extinguishing devices – Housing structure
Reexamination Certificate
2000-05-25
2001-10-02
Donovan, Lincoln (Department: 2832)
High-voltage switches with arc preventing or extinguishing devic
Arc preventing or extinguishing devices
Housing structure
C218S151000
Reexamination Certificate
active
06297465
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to circuit breakers and, more particularly, to an improved arc chute for a circuit breaker. Specifically, the invention is related to an arc chute having arc plates that are mounted in grooves formed in the arc chute wrapper.
2. Description of the Related Art
Numerous types of circuit breakers are known and understood in the relevant art. One of the purposes for which circuit breakers are provided is to interrupt an electrical circuit on command or according to certain criteria. Circuit breakers thus typically include a set of stationary electrical contacts and a set of moveable electrical contacts. The stationary and moveable contacts are in physical contact with one another when it is desired that the circuit breaker provide electricity therethrough to a load. When it is desired to interrupt the circuit, however, the moveable contacts are moved away from the stationary contacts, thus removing the moveable contacts from physical contact with the stationary contacts, creating a space therebetween, and interrupting the circuit.
As is understood in the relevant art, however, the movement of the moveable contacts away from the stationary contacts results in the formation of an electrical arc in the space between the moveable and stationary contacts beginning at the time the moveable and stationary contacts are initially separated. Such an arc is undesirable for a number of reasons. For example, the arc evidences current flowing through the circuit breaker to the load when it is desired that no such current should flow thereto. Additionally, an arc extending between the stationary and moveable contacts often results in vaporization or sublimation of the contact material itself, eventually resulting in destruction or pitting of the moveable and stationary contacts. It is thus desired to eliminate any such arcs as soon as possible upon their propagation.
As is understood in the relevant art, the moveable contacts typically are mounted on pivoting arms that pivot the moveable contacts away from the stationary contacts. An arc chute is provided along the path of each arm to break up and dissipate such arcs. Such arc chutes typically include a plurality of spaced apart arc plates mounted in a wrapper, the arc plates being aligned with the axis about which the arm pivots. As the moveable contact is moved away from the stationary contact, the moveable contact moves past the ends of the arc plates, with the arc being magnetically urged toward and between the arc plates. The arc plates are electrically insulated from one another such that the arc is broken up and extinguished by the arc plates.
Such arc chutes are not, however, without limitation. For instance, arc chutes of the type known and understood in the relevant art have heretofore been manufactured using arc plates formed with spinning tabs extending outwardly therefrom and extending through holes formed in the wrapper. Such spinning tabs and holes are indicated generally at the numerals
27
A and
47
A, respectively, in
FIG. 6
of U.S. Pat. No. 4,963,849 to Kowalczyk et al. The spinning tabs are then compressed to retain the arc plates in fixed relation to the wrapper. The outer surface of the wrapper is then coated with a layer of ceramic paint to eliminate shorts between the compressed spinning tabs of adjacent arc plates. Such shorting can occur when an arc travels through a hole formed in the wrapper to the exterior of the wrapper and thence to another arc plate or to the circuit breaker housing. The aforementioned manufacturing process is less than fully reliable in eliminating shorts.
It is thus desired to provide an arc chute wrapper that overcomes the problems of arc chute wrappers heretofore known in the art and that is relatively simple and inexpensive to manufacture.
SUMMARY OF THE INVENTION
In view of the foregoing, an arc chute wrapper in accordance with the present invention is a two-piece conjoined member formed with a plurality of grooves, the grooves being structured to receive a plurality of spaced apart arc plates. The arc chute wrapper is free of holes extending therethrough, and the arc plates are free of spinning tabs.
An aspect of the present invention is to provide a circuit breaker incorporating an arc chute, the general nature of which can be stated as including a wrapper, the wrapper having an inner surface and an outer surface, the wrapper being formed with a plurality of grooves extending into the wrapper from the inner surface, and a plurality of arc plates, the arc plates being mounted in the grooves.
Another aspect of the present invention is to provide an arc chute wrapper that is structured to extend at least partially around a plurality of arc plates, the general nature of which can be stated as including a generally U-shaped body formed with a plurality of grooves, the grooves being structured to at least partially receive arc plates therein.
Another aspect of the present invention is to provide a method of manufacturing a wrapper for an arc chute of a circuit breaker, the general nature of which can be stated as including the steps of shaping the wrapper into a general U-shape and forming a plurality of grooves in the wrapper.
These and other aspects and advantages of the present invention will be more readily understood from the following description.
REFERENCES:
patent: 2243038 (1941-05-01), Ludwig
patent: 2363606 (1944-11-01), Maseng
patent: 2468422 (1949-04-01), Wood
patent: 2477189 (1949-07-01), Lerstrup
patent: 2590543 (1952-03-01), Kalaway
patent: 2648742 (1953-08-01), Edmunds
patent: 2687462 (1954-08-01), Cellerini
patent: 2942083 (1960-06-01), Walker et al.
patent: 3662133 (1972-05-01), Bould et al.
patent: 4056798 (1977-11-01), Malick
patent: 4743720 (1988-05-01), Takeuchi et al.
patent: 4963849 (1990-10-01), Kowalczyk et al.
patent: 5539170 (1996-07-01), Palmer et al.
Dravis Justin Matthew
Groves David Herman
Donovan Lincoln
Eaton Corporation
Moran Martin J.
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