Pipe joints or couplings – Roof or floor drain flashing type
Utility Patent
1998-05-27
2001-01-02
Safavi, Michael (Department: 3635)
Pipe joints or couplings
Roof or floor drain flashing type
C277S607000, C285S110000, C285S231000, C285S347000
Utility Patent
active
06168208
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to sealing grommets for use in coupling in sealed relation a roof drain pipe and a co-operating leader pipe, and more particularly relates to such sealing grommets where the outside diameter of said drain pipe is smaller than the inside diameter of said co-operating leader pipe by an unspecified distance.
BACKGROUND OF THE INVENTION
In buildings having a flat roof, it is necessary to use one or more roof drains to permit water to drain from the roof. Typically, a conventional roof drain comprises an upper gravel stop portion which empties at its lower extent into a funnel shaped mouth portion. A removable metal or PVC strainer sits atop the mouth portion, and is concentrically surrounded by the gravel stop portion. A drain pipe is concentrically attached to the base of the mouth portion, so as to depend from the interior surface of the roof when the roof drain is installed. The bottom end of the drain pipe is inserted into the top end of a substantially vertically disposed leader pipe, so as to be connected in fluid communication therewith. The leader pipe is, in turn, operatively connected at its opposite other end to the building's storm sewer system so as to lead the water received by the roof drain away from the building in a controlled manner.
In order to preclude possible backflow of water upwardly from the leader pipe and out of the radially disposed gap between the leader pipe and the drain pipe, it is standard practice to use an annular grommet, which grommet is essentially an “O”-ring, disposed between the outside annular surface of the bottom end portion of the drain pipe and the inside annular surface of the top end portion of the co-operating leader pipe.
There are significant problems associated with such conventional prior art grommets, and accordingly with the connection of drain pipes to leader pipes using such conventional prior art grommets. While conventional prior art grommets do provide a seal between the drain pipe and the co-operating leader pipe under ideal conditions which offer close tolerances, they are know to be prone to leaking, especially if the drain pipe and the co-operating leader pipe have irregularities in their outer and inner surfaces, respectively, or are axially offset one with the other, or where significant mis-alignment of the drain pipe with the leader pipe occurs over time due to shifting of the roof deck relative to the leader pipe, or on account of differential expansion or contraction between the drain pipe and the leader pipe.
Also, it is common practice to use one standard conventional drain pipe on most, or all, roof drains, which drain pipe has a standard outside diameter. However, two sizes of leader pipes are conventionally used with this standard outside diameter drain pipe. While both sizes of conventional leader pipes are of a common outside diameter, one size, commonly known as “Schedule 80” pipe, has thicker walls, and therefor has a smaller inside diameter than does the other size, commonly known as “Schedule 40” pipe. Accordingly, two different sizes of conventional “O”-ring type grommets must be used, depending on which size of leader pipe is used. It is highly undesirable to have to use two sizes of conventional “O”-ring type grommets since two sets of grommets must be kept in inventory. Moreover, it is inconvenient to have both sizes of conventional “O”-ring type grommets available on hand at each job site, and it frequently occurs that the necessary size is not available. Given the timing pressures extant on modern construction sites, it has, on occasion, been the case that the wrong size “O”-ring has been used in particular installations, with the resultant loss of sealing integrity in these installations.
It is therefore an object of the present invention to provide a sealing grommet for use in coupling together in sealed relation a drain pipe and a co-operating leader pipe, which sealing grommet effects a substantially leak-proof seal between the drain pipe and the co-operating leader pipe, even where the diameter of the pipes may vary somewhat in the area of sealing, due to surface irregularities or other deformities in the respective pipes.
It is another object of the present invention to provide a sealing grommet for use in coupling together in sealed relation a drain pipe and a co-operating leader pipe, which sealing grommet effects a substantially leak-proof seal between the drain pipe and an axially offset co-operating leader pipe.
It is a further object of the present invention to provide a single sealing grommet for use in coupling together in sealed relation a drain pipe of a known outside diameter and a co-operating leader pipe having a range of possible inside diameters.
It is yet another object of the present invention to provide a single sealing grommet for use in coupling in sealed relation a drain pipe and a co-operating leader pipe, wherein the outside diameter of said drain pipe is smaller than the inside diameter of said co-operating leader pipe by an unspecified distance.
It is yet a further object of the present invention to provide a single size sealing grommet for use in coupling in sealed relation a drain pipe and a co-operating leader pipe, and thereby preclude the necessity to store in inventory and make available at job sites more than one size of sealing grommet.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention there is disclosed a sealing grommet for use in coupling in sealed relation a drain pipe depending from a roof and a co-operating leader pipe. The bottom end portion of the drain pipe is inserted into the top end portion of the co-operating leader pipe. The outside diameter of the drain pipe is smaller than the inside diameter of the co-operating leader pipe by an unspecified distance. The sealing grommet comprises an annular base portion having top, bottom, radially inner side and radially outer side surfaces. An annular interior wall portion extends upwardly from the base portion to terminate at a top edge, and is defined by opposed inner and outer wall surfaces. The interior wall portion has an overall inside diameter defined by the inner wall surface. A substantially resilient annular exterior wall portion extends upwardly and outwardly from the base portion in spaced apart relation to the annular interior wall portion, to terminate at a top edge, and is defined by opposed inner and outer wall surfaces. The exterior wall portion has an overall outside diameter defined by the outer wall surface. The bottom end portion of the drain pipe is retained within the substantially resilient annular interior wall portion in sealed engagement with the inner wall surface. The top end portion of the co-operating leader pipe surrounds the substantially resilient annular exterior wall portion in sealed engagement with the outer wall surface, thereby coupling in sealed relation the drain pipe and the co-operating leader pipe. The sealing grommet is preferably injection molded as a monolithic structure from a vulcanized synthetic rubber material, most preferably ethylene propylene diene monomer (EPDM).
Other advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly described hereinbelow.
REFERENCES:
patent: 1282535 (1918-10-01), Bropson
patent: 2284416 (1942-05-01), Gordon
patent: 2561884 (1951-07-01), Perrow
patent: 3510140 (1970-05-01), Hermann
patent: 3909412 (1975-09-01), Patry
patent: 4505814 (1985-03-01), Marshall
patent: 2128446 (1997-06-01), None
Kusner Mark
Safavi Michael
LandOfFree
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