Abstract:
A self-adhesive gasket having a pressure sensitive adhesive on one side or on both sides can be used in place of plumbers putty to seal sinks to countertops, faucets to sinks, and strainers and pop ups to sinks and tubs. The gasket is preferably preformed from a flexible cellular plastic, preferably a closed cell urethane foam. The gasket may be used in a multitude of plumbing application to form a liquid seal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of copending U.S. provisional patent application serial No. 60/288,864 filed May 4, 2001, the teachings of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to gaskets and more particularly to a self-adhesive cellular plastic gaskets for use in plumbing. 
     DESCRIPTION OF RELATED ART 
     Plumbers for many years have used plumber&#39;s putty to form a liquid seal around sink strainers, pop ups, bath drains, faucets, and sinks. The putty is sold in bulk and has the consistency of cookie dough. The plumber takes a clump of putty and works it in his hand to form a bead typically less than ½″ in diameter. When the putty is cold it becomes more difficult to form into a bead. The forming of the putty into a bead is time consuming and is prone to error. After the plumber forms the putty into a bead, he then secures the bead to one of the two items to be joined and then presses the two items together. The two items are then mechanically fastened together with screws, bolts, clips, or other fastener. As the two items are brought together, the putty oozes out. To finish the installation, the plumber must remove any excess putty. One of the biggest drawbacks of using the putty is the amount of time necessary to do a good job. Another drawback of using putty is that the putty tends to stain the plumber&#39;s hand and any item the plumber contacts. 
     Rubber gaskets have been used for many years to provide a waterproof joint when joining plumbing flanges. Often the rubber gaskets are used to join two flanges that do not rotate in relationship to each other. The rubber gasket is inserted between the flanges and then bolts are tightened to pull the flanges together. A drawback to the rubber gaskets is that they tend to move around as the items to be joined are pulled together. 
     Rubber gaskets have been used between items that rotate in relation to each other such as a sink strainer and a sink with limited success. As the strainer is pulled towards the sink by a nut on the opposite side of the sink, the rubber gasket tends to be squished outward and leaves a gap which can allow water or other liquids to escape. 
     Common weather stripping is well known. This product is frequently a thick but narrow strip of closed cell plastic flexible foam with a single layer of pressure sensitive adhesive on one surface that is protected by a release liner. The release liner is removed and the weather stripping is adhered or stuck around a doorframe, a window frame, etc. to seal out wind and noise. The weather stripping is typically positioned between two items that are not intended to be secured together permanently. 
     There is a need for a self-adhesive gasket that will overcome the deficiencies in the prior art and a method for joining plumbing components together to form a liquid tight seal. 
     SUMMARY OF THE INVENTION 
     A self-adhesive gasket is provided comprising a layer of pressure sensitive adhesive applied to one or both sides of a layer of flexible cellular plastic. The gasket may be formed in any shape, including, but not limited to, circles and rectangles, to seal plumbing components together. The shape is preferably formed by die-cutting a self-adhesive cellular plastic. Alternatively, the gasket may be formed from a narrow strip of cellular plastic having an adhesive secured on one or both sides, the user manually aligning the gasket on the surface to be joined. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a sink strainer assembly in accordance with the present invention. 
     FIG. 2 is an exploded view of shower or tub drain assembly in accordance with the present invention. 
     FIG. 3 is an exploded profile view of a sink or tub secured to a countertop or other surface in accordance with the present invention. 
     FIG. 4 is an exploded profile view of a faucet secured to a countertop or other surface in accordance with the present invention. 
     FIG. 5A is a top view of a preformed gasket in accordance with the present invention. 
     FIG. 5B is a profile view of preformed gasket of FIG.  5 A. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to FIG. 1, a sink strainer assembly  100  is shown. The assembly  100  comprises a strainer body  102 , a gasket  104 , a washer  106 , a clamp cup  108 , a locknut  110 , and a tailpiece washer  112 , coupled to a tailpiece  114 . The gasket  104  may be a compressible gasket, preferably comprised of cellular plastic, more preferably a closed cell urethane foam, and even more preferably International Tape #308SF. The gasket is preferably die cut having a circular inner and outer diameter. The thickness of the gasket and the inner and outer diameter can be modified to meet the specific application. The Gasket  104  is shown as circular, but it can be any other shape to meet the specific application. The gasket has an adhesive layer on a first side and a second and opposing side. Each of the adhesive layers may be covered by a release layer to prevent two gaskets from inadvertently sticking together. The installer, typically a plumber, removes the upper release layer and secures the gasket  104  to the bottom surface of the sink strainer  102 . The plumber then removes the lower release layer and inserts the strainer  102  with the gasket  104  secured thereto in an opening  116 A in a sink  116 . The installer then threads the locknut  110  onto the threaded portion of the sink strainer  102 . By tightening the locknut  110 , the gasket  104  is compressed between the bottom surface of the sink strainer  102  and the upper surface of the sink  116 . Since the sink strainer  102  is adhesively coupled to the upper surface of the sink, the installer may not have to prevent the sink strainer  102  from rotating while he tightens the locknut  110 . The gasket  104  forms a water-tight seal between the sink strainer and the sink. In the prior art the seal between the sink strainer and the sink was formed by plumber putty. Alternatively, the gasket  104  may be applied to the sink  116  first. 
     FIG. 2 shows a shower or tub drain assembly  200 . The assembly comprises a strainer  202 , a gasket  204 , a rubber washer  210 , and a fiber washer  212  coupled to a drain shoe  214 . The inner surface of the drain shoe is threaded to match the threads of the strainer  202 . In this application the drain shoe is stationary and the strainer  202  is rotated during installation. The gasket  204  may be a compressible gasket, preferably comprised of cellular plastic, more preferably a closed cell urethane foam, and even more preferably International Tape #308SF. The gasket is preferably die cut having a circular inner and outer diameter. The thickness of the gasket and the inner and outer diameter can be modified to meet the specific application. The gasket  204  is shown as circular, but it can be any other shape to meet the specific application. The gasket has an adhesive layer on a first side. The adhesive layer may be covered by a release layer to prevent two gaskets from inadvertently sticking together. The installer removes the release layer and secures the gasket  204  to the bottom surface of the sink strainer  202 . The installer then inserts the strainer  202  with the gasket  204  secured thereto in an opening  206 A in a tub or shower floor  206 . The installer then threads the strainer into the threaded portion of the drain shoe  214 . By rotating the strainer  202 , the gasket  204  is compressed between the bottom surface of the strainer  202  and the upper surface of the tub or shower floor  206 . Since the strainer  202  needs to rotate relative to the surface of the tub or shower floor  206 , no adhesive is applied to the lower surface of the gasket  204 . Alternatively, the lower surface of the gasket  204  may include an adhesive layer, and the installer lubricates the surface to temporarily disable the adhesive. The installer may user water or saliva. The gasket  204  forms a water-tight seal between the strainer  202  and the tub or shower floor  206 . In the prior art the seal between the strainer and the tub or shower floor was formed by plumber putty. 
     FIG. 3 shows an exploded profile view of a sink assembly  300 . The sink assembly comprises a sink or tub  302 , a surface  306 , (a countertop for example), and a gasket  304 . The gasket  304  is compressed between the sink or tub  302  and the surface  306  by the weight of the tub or sink and the force provided by a mechanical fastener  308 . The gasket  304  may be a compressible gasket, preferably comprised of cellular plastic, more preferably a closed cell urethane foam, and even more preferably International Tape #308SF. The gasket  304  is preferably die cut in a shape such that the gasket fits between the outside edge  310  of the opening  312  in the surface  306  and the outside edge of the sink or tub  302 . The thickness of the gasket and the dimensions can be modified to meet the specific application. The gasket has a first adhesive layer on a first side and may have a second adhesive layer on a second and opposite side. The adhesive layers may be covered by a release layer to prevent two gaskets from inadvertently sticking together. The installer removes the first release layer and secures the gasket  304  to the bottom surface of the sink or tub  302 . The installer then removes the second release layer and inserts the sink or tub  302  with the gasket  304  secured thereto in the opening  312  the surface  306 . The installer then tightens the sink or tub  302  to the surface  306  using the mechanical fastener  308 . The gasket  304  is compressed between the bottom surface of the sink or tub  302  and the surface  306  and forms a water-tight seal. In the prior art the seal between the sink or tub  302  and the surface  306  was formed by plumber putty. Alternatively, the gasket  304  may be applied to the surface  306  first. 
     FIG. 4 shows an exploded profile view of a faucet assembly  400 . The faucet assembly comprises a faucet  402 , a surface  406 , (a countertop for example), and a gasket  404 . The gasket  404  is compressed between the faucet  402  and the surface  406  by the force provided by a mechanical fastener  410 . The gasket  404  may be a compressible gasket, preferably comprised of cellular plastic, more preferably a closed cell urethane foam, and even more preferably International Tape #308SF. The gasket  404  is preferably die cut in a shape such that the gasket fits under the skirt along the bottom surface of the faucet  402 . The thickness of the gasket and the dimensions can be modified to meet the specific application. The gasket has a first adhesive layer on a first side and may have a second adhesive layer on a second and opposite side. The adhesive layers may be covered by a release layer to prevent two gaskets from inadvertently sticking together. The installer removes the first release layer and secures the gasket  404  to the bottom surface of the faucet  402 . The installer then inserts the faucet  402  with the gasket  404  secured thereto in an openings  408  in the surface  406 . The installer then threads the mechanical fastener  410  onto the threaded portion  414  of the faucet  402  and tightens the faucet  402  to the surface  406 . The gasket  404 i is compressed between the bottom surface of the faucet  402  and the surface  406  and forms a water-tight seal between the faucet  402  and the surface  406 . In the prior art the seal between the faucet and the sink was formed by plumber putty. Alternatively, the gasket  404  may be applied to the surface  406  first. 
     FIG. 5A shows a gasket  500 . The gasket is useful in FIGS. 3 and 4. The gasket is shown rectangular having outside dimensions X 2  and Y 2 . The gasket is shown having a width X 1  and Y 1 . X 1  and Y 1  may be the same or different. The gasket  500  comprises a compressible layer  514 , preferably cellular plastic, a first adhesive layer  512  covered by a first release layer  510 . The gasket  500  may include a second adhesive layer  516  covered by a second release layer  518 . The compressible layer  514  having a thickness Z. A preferred range for the thickness is 0.05-0.5″. A suitable compressible material is available from International Tape part No. 308SF. The adhesive layer is preferably a pressure sensitive adhesive, more preferably an acrylic adhesive. 
     Alternatively, the gasket can be sold in strips on a roll, the width of the strip ranging from ⅛″ to 1″. The installer would remove the release layer and secure the strip to the item to be sealed. 
     The gaskets may be shaped as circles (see FIGS.  1  and  2 ), squares or rectangles (see FIGS. 3,  4 , and  5 ) or any other desired shape. Alternatively the gasket may have small cut outs for bolt, screw, fastener, etc. 
     Although particular embodiments of the invention have been described in detail, it is understood that the invention is not limited correspondingly in scope, but includes all changes and modifications coming within the spirit and terms of the claims appended hereto.