1. Field of the Invention
The invention relates generally to bathtub overflow assemblies and more particularly to an overflow assembly equipped with a test cap to permit pressure testing of the waste plumbing during construction.
2. Description of the Related Art
In new construction, plumbers are required to test the assembled waste or drain plumbing of a structure before closure of wall and ceiling surfaces. Such testing is performed under pressure to detect leaks or flaws in the waste plumbing system so that such leaks are repaired while the plumbing is still easily accessible.
Bathtub overflow assemblies are well-known plumbing fixtures that connect the overflow opening of a bathtub to the bathtub drain. The overflow opening in the bathtub is typically positioned on an end wall of the bathtub at a pre-selected elevation to limit the maximum level of water in the tub and prevent bathtub overflow. Water above the level of the overflow opening is safely drained through the opening and overflow assembly into the bathtub drain.
The overflow assembly typically includes an overflow elbow having an inverted L-shape. An inlet of the overflow elbow is sealingly engaged with the bathtub overflow opening. The overflow elbow provides a flow passage extending downwardly to connect the bathtub overflow opening with the bathtub drain. There are a number of well-known arrangements for fixing the inlet of the overflow elbow to the bathtub overflow opening in sealed relationship. The integrity of this seal is important to prevent water leaking around the overflow elbow.
An overflow assembly relevant to the present invention is shown in U.S. Pat. Nos. 6,675,406 and 6,637,050. The overflow elbow is provided with a radially extending flange positioned to compress a sealing gasket against the outside surface of the tub around the tub overflow opening. A cylindrical fitting having a threaded outside surface extends through the tub overflow opening and is threadably engaged by a retainer nut that bears against the inside surface of the tub. A thin diaphragm is sealed over the end of the overflow elbow to seal the overflow inlet during testing of the drain plumbing. After testing, the thin diaphragm is cut away and a trim cap is placed over the inner end of the overflow elbow and retainer nut to provide a finished appearance to the installed assembly. One potential drawback to this approach is that the thin diaphragm can be damaged during manufacture, shipping or installation of the overflow assembly. A damaged diaphragm would require replacement of the overflow elbow or some alternative means of sealing the overflow inlet during testing of the drain plumbing.
It is also known to provide a threaded test cap separate from the threaded retainer nut to cover the overflow inlet during testing of the drain plumbing. After testing, the test cap is unthreaded from the inner end of the overflow elbow and the decorative cap is installed. Manufacture and packaging of separate retainer nuts and test caps is costly and presents the potential that one or the other may be omitted from the packaged assembly.
A further alternative overflow assembly configuration is disclosed in U.S. Pat. No. 6,484,331 (the '331 patent). The '331 patent overflow assembly includes an overflow elbow having an internally threaded overflow opening that receives one end of an externally threaded overflow cap extending through the tub overflow opening. A gasket is compressed between the overflow elbow and the outside surface of the tub around the overflow opening. The overflow cap includes a test cap molded integrally with the overflow cap. The test cap is molded with a thin, breakable connection to the overflow cap such that, after testing of the drain plumbing system, the test cap is broken away from the overflow cap to open the overflow inlet. A potential drawback of the '331 overflow assembly structure is that the threaded joint between the overflow cap and the overflow elbow is positioned outside the tub. This presents the potential for leakage that is not present in an overflow elbow configured to extend integrally through the tub overflow opening.
The present invention employs an overflow elbow having an externally threaded cylindrical fitting that extends integrally through the tub overflow opening. An internally threaded retainer nut with integrally molded test cap is threadably engaged with the overflow cylindrical fitting to compress gaskets against both the inside and outside surfaces of the tub. The test cap is integrally molded with the retainer nut with a thin, breakable connection between the nut and cap. An undercut lip on the test cap facilitates use of a prying tool to break the thin connection and remove the test cap after testing of the drain plumbing.
The tub overflow assembly includes an overflow elbow, an outside gasket, an inside gasket, an o-ring seal, the integrated retainer nut and test cap and a trim cap. The outside gasket is a thick sponge type gasket configured for compression between a radially extending flange of the overflow elbow and the outside surface of the tub around the overflow opening. The inside gasket is a flat rubber gasket that is compressed between one end of the retainer nut and the inside surface of the tub around the overflow opening. The retainer nut is configured with a channel or seat for the inside gasket. The inside gasket prevents water from escaping from behind the retainer nut and through the overflow opening. The outside gasket is configured to stop any water that may get past the inside gasket.
The overflow elbow includes a cylindrical fitting configured to extend through the tub overflow opening and into the tub. The cylindrical fitting has a generally cylindrical outside surface with a threaded section and an unthreaded section including a groove that receives an o-ring seal. The threaded section of the cylindrical fitting outside surface is adjacent the flange and the unthreaded section extends from the threaded section. The retainer nut has a generally cylindrical configuration complementary to the cylindrical fitting. The retainer nut inside surface is partially threaded and partially unthreaded. The unthreaded portion of the retainer nut inside surface is configured to radially compress and seal against the o-ring seal retained in the groove defined by the cylindrical fitting unthreaded section. The depth of the inside surface of the retainer nut and the overlapping cylindrical configuration of the overflow elbow and retainer nut and test cap accommodate variations in the thickness of the bathtub wall.
The test cap is molded integrally with the retainer nut to extend across and close the unthreaded end of the generally cylindrical retainer nut. The integrated test cap permits testing of the drain plumbing without installation of an additional component. After testing, a prying tool is inserted beneath an undercut lip on the test cap and used to pry the test cap away from the retainer nut. The retainer nut and test cap are integrally molded from ABS plastic with a thin skin of approximately 0.020 thickness surrounding the test cap and connecting the test cap to the retainer nut cylindrical portion. The periphery of the retainer nut includes lugs having an undercut beveled edged adjacent the inside surface of the tub. This undercut edge receives a complementary protrusion on the trim cap such that the trim cap is engaged over the retainer nut in a snap fit.
The inventive overflow assembly will now be described with reference to
The overflow elbow 12 is molded from PVC or ABS plastic for compatibility with the plastic employed in the remainder of the drain plumbing system. The overflow elbow 12 extends from a lower end portion defining a socket 24 configured to receive standard plastic pipe to an upper end portion including a cylindrical fitting 26 configured to extend into a bathtub through the tub overflow opening. The overflow elbow 12 is so called because of its inverted L-shape, which provides a flow passage extending downwardly to facilitate connection of the tub overflow opening with the bathtub drain. A flange 28 radially projects from a rear end of the cylindrical fitting 26 of the overflow elbow 12. This flange engages the outside gasket 14 to compress it against the outside surface of the tub surrounding the overflow opening. The outside surface of the cylindrical fitting 26 includes a threaded section 26a adjacent the flange 28 and an unthreaded section 26b extending from the threaded portion 26a. The unthreaded portion 26b defines a circumferential groove 30 configured to receive the O-ring seal 18.
As shown in
The test cap 34 is integrally molded with the retainer nut to close the outer end of the cylindrical side wall 36. As best shown in
The O-ring seal 18 enhances the sealed engagement between the cylindrical fitting 26 of the overflow elbow and the side wall 36 of the retainer nut 20. In the absence of the o-ring seal 18, it would be possible for water to traverse the coarse threads of the retainer nut and overflow elbow to cause a leak. The threads of the disclosed embodiment are approximately eight threads per inch at a diameter of approximately 2⅜″. The axial dimension of the threaded portion 38 of the retainer nut is approximately 0.450″. The overall depth of the retainer nut cylindrical extension is approximately 0.985″.
While a preferred embodiment of the foregoing invention has been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.
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