Electricity: conductors and insulators – Conduits – cables or conductors – Single duct conduits
Reexamination Certificate
2000-07-14
2003-04-29
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Single duct conduits
C174S068300, C016S002100, C439S604000
Reexamination Certificate
active
06555749
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to liquid tight conduit fittings and, more particularly, to liquid tight conduit fittings used to terminate flexible conduit to electrical enclosures.
Liquid tight conduit fittings are commonly used to terminate an end extent of a length of flexible conduit to an electrical enclosure such as a junction box. It will be appreciated that such conduit fittings, which are often formed from a plastic material such as UV resistant PVC, may be used in both exterior and interior applications. The fittings must be able to withstand certain environmental and/or physical conditions without failure.
One such category of fittings is used to provide a liquid tight connection between a section of type B liquid tight conduit and an electrical enclosure. Usage applications include exterior air conditioning wiring, swimming pool pumps, hot tubs, compressors, outdoor lighting, heat pumps or any other application requiring electrical service of 600 VAC or less and which is not subject to high levels of physical abuse. It will be appreciated that such fittings may also be used in machine tool environments.
Prior art conduit fittings include a gland end having a helical rib formed about the outer surface thereof. This gland end is inserted into an end extent of flexible conduit via a twisting process. A bushing and/or sleeve is positioned proximate the terminating end of the conduit to assist in preventing ingress of moisture into the interior of the conduit. Moreover, the terminating end of the conduit, which has often been cut by the installer and may include uneven and/or unsightly edges, remains visible after connection to the prior art fitting. This visibility of the terminating end of the conduit may provide the fitting/conduit assembly with an aestheticly displeasing appearance. Finally, the threaded enclosure-connecting end of the fitting which couples to the electrical enclosure must be attached in a watertight manner. Prior art fittings employ a conventional O-ring seal located between the fitting and the electrical enclosure. The use of conventional O-ring seals, however, may provide insufficient sealing in certain environments and/or under certain conditions.
There is therefore a need in the art for a liquid tight conduit fitting which provides improved sealing between the gland end and the end extent of the conduit without the necessity of relying on a bushing and/or sleeve. There is a further need in the art for a liquid tight conduit fitting wherein the terminating end of the length of conduit is enclosed by the fitting to provide both increased sealing and improved aesthetics. Finally, there is a need in the prior art for a liquid tight conduit fitting wherein an improved seal is provided between the threaded enclosure-connecting end and the electrical enclosure upon securement therebetween.
SUMMARY OF THE INVENTION
The present invention, which addresses the needs of the prior art, relates to a fitting for coupling an end extent of flexible conduit to an electrical enclosure. The fitting includes a body having an enclosure-connecting end and a gland end. The enclosure-connecting end is sized and configured for securement to the electrical enclosure. The gland end includes a generally cylindrical outer surface sized for insertion within the end extent of the conduit. The gland end further includes a helical rib located on the outer surface and extending thereabout to facilitate insertion of the gland end within the end extent of the conduit. Finally, the gland end includes a sealing rib having a pitch of 0° located on the outer surface thereof and extending thereabout whereby a seal is provided between the outer surface of the gland end and the interior of the conduit.
The present invention also relates to an assembly of a body and a hood. The body includes a threaded enclosure-connecting end, a gland end and a circumferentially surrounding hub having a first interfitting structure. The hood includes a substantially tubular body having first and second ends. The first end includes an aperture having a second interfitting structure formed thereabout. The aperture is sized to allow the gland end of the fitting to extend therethrough whereby the first and second interfitting structures are assembled thereby securing the hood to the body. The second end of the hood defines an annular cavity about the gland end upon assembly to the body.
The present invention further relates to an assembly of a seal and a fitting for coupling an end extent of flexible conduit to an electrical enclosure. The fitting includes a body having an enclosure-connecting end and a gland end. The enclosure-connecting end is sized and configured for securement to the electrical enclosure. The gland end includes a generally cylindrical outer surface sized for insertion within the end extent of the conduit. The gland end further includes a helical rib located on the outer surface and extending thereabout to facilitate insertion of the gland end within the end extent of the conduit. The seal is positioned about the threaded enclosure-connecting end to provide a seal between the enclosure-connecting end and the electrical enclosure. The seal defines a cloverleaf-shaped cross section which provides plural sealing points for improved sealing between the fitting and the electrical enclosure.
As a result, the present invention provides a liquid tight conduit fitting which provides improved sealing between the gland end of the end extent of the conduit without the necessity of relying on a bushing and/or sleeve. The present invention also provides a liquid tight conduit fitting wherein the terminating end of the length of conduit is enclosed by the fitting to provide both increased sealing and improved aesthetics. Finally, the present invention provides a liquid tight conduit fitting wherein an improved seal is provided between the threaded enclosure-connecting end and the electrical enclosure upon securement therebetween.
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Hoffmann & Baron , LLP
Patel Dhiru R
Reichard Dean A.
Thomas & Betts International Inc.
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