Patent Abstract:
A method and apparatus for modifying a bathtub overflow drain to bypass potential leakage zones, i.e. between a bathtub liner and between connections of fittings through inserting a throat member from the innermost surface of the bathtub, which may be the innermost surface of a bathtub liner, to the interior of the standing portion of a drainpipe.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     This invention relates to bathtub overflow drains and is particularly related to inserts for originally installed bathtub drains. 
     BRIEF SUMMARY OF THE INVENTION 
     In the installation of bathtubs it is common that an overflow opening of the bathtub be connected to a drainpipe having a standing portion also connected to the bathtub drain and discharging downwardly to a sewer connection. A portion at the upper end of the drainpipe is angled to connect to the overflow opening. After installation it is not unusual for a gasket, positioned between the angled upper end of the drainpipe and the bathtub wall surrounding the overflow opening, to leak. This may be due to improper installation of the gasket or may be because of hardening and/or deterioration of the gasket with the passage of time. In any event, leakage past the gasket can be damaging to bathtub support structure and may run down the outer face of the bathtub. The water on the bathtub then causes the tub to rust, often without knowledge of a user of the tub until an entire section of the tub wall disintegrates and it becomes necessary to replace the entire tub. 
     It is also common to provide a bathtub lining of plastic material that will cover worn and damaged visible surface areas of a bathtub; Such liners are frequently formed in one piece to cover all exposed surfaces of the tub. If a bathtub liner is installed care must be taken to seal the overflow opening through the liner and the aligned overflow opening of the bathtub to prevent water moving between the liner and the bathtub. 
     Principal objects of the present invention are to provide an insert fitting for connection of the inlet face of a bathtub drain opening with a drainpipe and to provide a fitting that is easily installed and that will discharge into the existing, standing portion of the drain pipe to carry away overflow water, without requiring modification or change of pre-existing overflow drain structure. 
     Other objects are to provide such an insert fitting that will accommodate the use of existing tub drain stopper operating mechanisms and that will effectively prevent seepage of overflow water flow between a tub liner and the wall of a bathtub in which a liner is installed. 
     Principal features of the invention include a throat that will mount to either a bathtub wall or a bathtub liner wall and that will extend through the overflow opening and an angled discharge pipe section, into the standing portion of the drainpipe, so that overflow water entering the throat from the bathtub is discharged from the throat into the standing portion of the drain pipe. 
     Still another feature of the invention is a flexible throat that will accommodate use of existing operating levers and linkages to control the bathtub drain valve while carrying overflow water past the drainpipe connection to the bathtub and into the standing portion of the drainpipe. 
     It is yet another feature of the invention that the shape of the throat insures flow of all water from the throat either back into the bathtub or into the standing portion of the drainpipe. 
     Other objects and features of the invention will become apparent to those skilled in the art to which the invention pertains from the following detailed description and drawings, disclosing what is presently contemplated as being the best mode of the invention. 
    
    
     DRAWINGS 
     In the drawings: 
     FIG. 1 is a sectional view taken through a portion of a bathtub liner, a bathtub wall and centrally through the throat of the invention; 
     FIG. 2, a sectional view taken on the line  2 — 2  of FIG. 1; 
     FIG. 3, a front elevation view of a retaining plate for securing the throat of the invention and an overflow cover plate to a bathtub liner or a bathtub wall; 
     FIG. 4, a view like that of FIG. 1, but showing an alternate retaining plate suitable for use with a bathtub drain plug operating mechanism; 
     FIG. 5, a front elevation view of the alternative retainer plate of FIG. 4; and 
     FIG. 6, a front elevation of a seal positioned between a flange of the throat and the bathtub liner or bathtub wall. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings: 
     In the illustrated preferred embodiment of the invention, a throat  10  is shown secured to a bathtub liner  12  and extending through the liner and a bathtub wall  14  and into a drainpipe  16 . Drainpipe  16  includes an angled end portion  18 , with an end flange  20  shown connected to the bathtub wall  14 . The angled end portion  18  is shown forming a right angle connection with a standing portion  24  of the drainpipe  16 , although it should be apparent that a connection other than a right angle connection may be provided between the angled end portion  18  and standing portion  24  and, in fact, in some instances the connections are curved or differently angled. A seal  26  is provided between end flange  20  and the bathtub wall  14 . Seal  26  is the seal that often allows leakage of the water from the bathtub. 
     Throat  10  has a flange  28  surrounding and extending outwardly from an inlet end  30 , a central wall portion  32  tapered from the flange  28  towards a flared wall portion  34 , that terminates in a discharge end  36 . Preferably, throat  10  is formed of a long lasting rubber, such as silicone rubber, or another rubber or plastic material that will be flexible, while generally maintaining its formed shape and capable of withstanding the corrosive effect of water, soap and other chemicals passed through the throat during use. Water in the throat  10  will either flow along tapered wall portion  32  back into the bathtub or through the flared wall portion  34  into the drainpipe  24 . When made to be somewhat flexible, the throat can be bent during installation to allow it to fit into a drainpipe having an angled end portion other than the right angle configuration shown. 
     The length of throat  10 , between flange  28  and the discharge end  36 , is such that when flange  28  is positioned against the inner surface of liner  12 , or if no liner is provided the inner surface  38  of bathtub wall  12 . The central wall portion  32  and flared wall portion  34  of throat  10  extend through the angled end portion  18  such that the discharge end  36  terminates within the standing portion  24  of drainpipe  16 . 
     As shown best in FIGS. 1-3, flange  28  of throat  10  is bonded to the face of bathtub liner  12 , or, if no liner is provided, with the inner surface  38  of the bathtub wall  14  with a bead of adhesive  40 . The flange  28  is further secured to the tub liner or bathtub with screws  42  inserted through holes  44  in the retainer plate  46 , holes in flange  28  of the throat  10 , aligned holes through the seal  26  and screwed into the threaded holes  50  of flange  20 . A screw  52  through a cover plate  54  is screwed into a threaded hole  62  in a bar  64  that extends across the central opening  66  of retainer plate  46  secures the cover plate to the liner or bathtub wall. 
     A seal  58 , FIG. 6 may be inserted between flange  28  of throat  10  and the liner (or bathtub) in place of the bead of adhesive  40 , if desired 
     As best seen in FIG. 4, the flexible throat  10  bends to accommodate use of a lever  70 , and linkage arms  72  and  74  used to operate a drain valve  76  within the standup portion  24  of drainpipe  16 . Such actuating mechanisms are well known, and generally extend through and are pivoted on a cover plate. In this embodiment a retainer plate  82  is used to secure the flange  28  of throat  10  in place. Screws inserted through holes in the cover plate and through the holes  84  of retainer plate  82 , FIG. 5, hold the retainer plate  82  in place. 
     Although a preferred form of my invention has been herein disclosed, it is to be understood that the present disclosure is by way of example and that variations are possible without departing from the subject matter coming within the scope of the following claims, which subject matter I regard as my invention.

Technology Classification (CPC): 4