Electricity: circuit makers and breakers – Multiple circuit control – Operating means
Reexamination Certificate
2000-06-05
2002-01-08
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Multiple circuit control
Operating means
C200S01600R, C200S043050, C200S051060
Reexamination Certificate
active
06337447
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to electrical disconnects. More specifically, the present invention relates to an electrical disconnect switch assembly.
U.S. Pat. No. 4,851,963 entitled “Weatherproof Air Conditioning Disconnect Switch” describes a simple switch enclosed within a metal enclosure that includes a pull-out handle that carries the movable contacts in and out of connection with the fixed contacts arranged within the switch housing. To prevent inadvertent replacement of the handle when the air conditioning equipment is being installed or repaired, the operator may retain the handle until such repair or installation is completed.
U.S. Pat. No. 5,272,297 entitled “Streamlined Air Conditioning Disconnect Switch” describes a switch contained within a metal enclosure wherein the switch utilizes a ramped movable contact arrangement for slidably opening and closing the switch contacts without the requirement of a removable pull-out handle. A plastic faceplate covering the switch terminals allows the use of a metallic enclosure of reduced depth.
Non-automatic (manual) electrical disconnects are located near electrical equipment such as motors, compressors, motor controls or other electrically driven machinery. Electrical disconnects allow maintenance personnel to manually isolate the machinery from electrical power when maintenance or replacement of the machinery is necessary, thus protecting the personnel from electric shock.
Industrial air conditioning and refrigeration equipment, and the disconnects that service this equipment, are often located on roof tops or other outdoor locations. Consequently, the electrical disconnects must not only protect personnel from the potential hazards of electric shock, but must also be water-resistant and tamper-proof.
Electrical disconnects generally comprise a disconnect switch assembly (switch) and related connecting equipment, e.g., lugs and ground terminals, housed within a disconnect enclosure (enclosure). When the disconnect is installed, the switch is electrically connected to both the power supply (line) wiring and the equipment (load) wiring via the lugs. Thus, the switch forms part of the electrical circuit providing electrical power to the electrically driven machinery. The electric disconnect switch may operate within a metal enclosure without the requirement of circuit breakers to turn the associated electric equipment on and off.
The switches come in a variety of configurations, e.g., toggle type and pull type. The disconnects must meet accepted industry standards, e.g., Underwriters' Laboratory (UL) standards or National Electric Code standards, depending on their use. The disconnects for air-conditioning (AC) disconnects must meet Article 430 of the National Electric Code, one such industry standard.
The enclosure is generally shaped as an elongated parallelepiped, with a top wall, a bottom wall, a back wall, two side walls, and a cover.
The cover allows access to the switch and related connecting equipment housed within the enclosure. The enclosure is generally constructed of plastic or metal, and it must meet a variety of accepted industry standards, including UL standards or National Electric Code standards, depending on their use. One such standard is UL 50, entitled “Standard for Safety for Enclosures for Electrical Equipment.”
The interior components of the electric disconnect, such as the handle assembly, are generally constructed of plastic materials and must comply with UL standards for strength and temperature. During production, prior art disconnects are assembled by mounting the base section of the handle assembly within the interior compartment of the enclosures with a plurality of mounting screws. Further, the line and load blades are secured to the handle assembly with a plurality of mounting screws. This method of assembly requires that an inventory of screws be maintained and controlled for this operation. Additionally, proper production tooling, e.g. screw guns, must be used. For these reasons the use of screws adds significant cost and labor to the production process.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, an electric disconnect switch assembly is mounted within a disconnect enclosure for manually disconnecting electrical equipment from a source of supply power. The electric disconnect switch assembly includes a receptacle and a handle assembly. The receptacle is attached to a bottom wall of the enclosure. The receptacle includes a load stab arranged in a first pocket and in contact with a load terminal lug and a line stab arranged in a second pocket and in contact with a line terminal lug. The handle assembly includes a handle grip projecting from one end and a line blade and a load blade extending from an opposite end thereof. The handle assembly is slidably arranged within the receptacle and the line blade and the load blade are moved into and out of contact with the line and load stabs by manual operation of the handle grip.
REFERENCES:
patent: 4472611 (1984-09-01), Schooh
patent: 4851963 (1989-07-01), Miller et al.
patent: RE34113 (1992-10-01), Miller et al.
patent: 5272297 (1993-12-01), Reichow et al.
patent: 5406449 (1995-04-01), Hicks et al.
patent: 5831228 (1998-11-01), Kuki et al.
patent: 6118091 (2000-09-01), Matsumoto et al.
Mertesdorf Daniel Ray
Thomson Mark H.
Tobin Michael
Wise Randall D.
Cantor & Colburn LLP
Friedhofer Michael
General Electric Company
Horton Carl B.
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