Electrical connectors – Uninterrupted support rail or uninterrupted contact – With means to join tandem rails or tandem contacts
Reexamination Certificate
2000-01-25
2001-10-02
Luebke, Renee (Department: 2833)
Electrical connectors
Uninterrupted support rail or uninterrupted contact
With means to join tandem rails or tandem contacts
C439S213000
Reexamination Certificate
active
06296498
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an electrical plug-in busways in which multiple electrically-isolated, conductive busbars are housed in elongated track sections for feeding electricity to take-off devices that may be inserted into the track, and, in particular, to busbar connectors between adjacent track sections.
2. Description of the Prior Art
It is common in factories, shops, offices and other buildings to provide overhead electrical power distribution tracks for providing a convenient source of electricity for lights, machines and other electrical devices in the buildings. Take-off devices are used to tap power from the track to the load apparatus. The load may be anything from a lamp to a three phase electrical machine. It is desirable to be able to insert take-off devices into or remove them from the track at any point along the track itself and make a secure electrical contact with the busbars.
Electrical power distribution tracks are typically comprised of an elongated housing containing multiple electrically-isolated, conductive busbars. Track lighting and continuous plug-in busway are typical of this type of track system. Track sections can be from 2 to 20 feet long. Sections of the track can be joined together by connectors to form long runs for power distribution.
The connectors between track sections must electrically connect the busbars in one track section to the busbars in the adjoining track section or sections. Connectors are also used to feed electrical power to the distribution tracks. Power feed connectors typically plug into the ends of the track sections. Typically, the busbar connector assembly contains conductive bars that make pressure contact with the busbars to provide the electrical connection between track sections.
A variety of busbar connectors are known in the art. One system of busbar connectors uses thin pieces of spring temper metal that is capable of carrying no more than 20 amperes of current. The spring metal is shaped so that the spring temper of the material exerts pressure contact points on the busbars.
Another system uses connector pins and sleeves. Conductive pins are installed between exposed busbars in adjoining track sections. The pins include either a spring pressure means or a screw pressure means. The ends of the busbars are exposed on all sides to receive the connectors or have hollow interiors for installation of the pins.
A third system uses solid metal connector bars and springs or screws for pressing the connector bars against the busbars in adjoining track sections.
An improved busbar connector is needed that substantially increases the contact pressure against the busbars in order to provide a more reliable contact that is capable of carrying higher currents than the prior art connectors. Improved busbar connectors are desired which lower construction costs, eliminate or substantially reduce the possibility of breaking the connector bars, provide insulated pressure screws, and do not require gaps between track sections.
SUMMARY OF THE INVENTION
The present invention satisfies all the above needs for an improved busbar connector for plug-in busways. This invention provides a busbar connector that is capable of higher current carrying capacity, is lower in cost, less prone to breaking of the connector bars, has insulated pressure screws and has no gaps between adjoining track sections.
This invention uses shunt wires made of strips of copper, spreader springs, and tapered set screws to press copper contacts on the shunt wires against busbars in the adjoining track sections. The shunt wires are preferably flexible to facilitate assembly of the connector, particularly when the connector is an elbow, tee, or crossover. The set screws are accessible from the edge of the connectors at the mouth of the track section so there is no need for a gap between the adjoining track sections. The shunt wires, springs and tapered set screws are contained in an insulating housing, and copper contacts on the shunt wires project from the housing for engagement against busbars in the busway. For installation of the connector in a busway, the tapered set screws are in the retracted position with the contact assemblies fitting loosely in the connector body so there is room for the copper contacts to move during the installation. Once installed, the screws are turned progressively toward the engaged position in which the taper on the end of the screws forces the spreader springs, shunt wires and copper contacts on the wires outwardly from the connector body. As the screws are turned, the contact pressure against the busbars increases. The spreader springs are made of material such that they flex only a minimal amount and directly transfer the screw pressure to the contact. The flexible shunt wire allows the contact to seat itself firmly and flatly against the busbar and not require precise alignment between adjoining busway sections. Each screw is tightened until adequate pressure is attained. This process is repeated at each contact assembly pair, typically four places in each busbar connector.
REFERENCES:
patent: 3601748 (1971-08-01), Hart
patent: 3605064 (1971-09-01), Routh
patent: 3831130 (1974-08-01), Valtonen
patent: 3871730 (1975-03-01), Hesse
patent: 4053194 (1977-10-01), Gilman
patent: 6039584 (2000-03-01), Ross
patent: 6093037 (2000-07-01), Lin
Star Line Track Busway, Universal Electric Corporation Catalog (undated).
Star Line Busway System, Universal Electric Corporation Catalog (undated).
Track Sections (undated).
GE Busway, Type LTG Busway Plug-in Dimensions (1997 Issue).
Power-Trac, Trac Systems Halo-2, Halo/Power-Trac Lighting (undated).
Brownlee David W.
Eckert Seamans Cherin & Mellott , LLC
Hammond Briggitte R
Luebke Renee
Universal Electric Corporation
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