Patent Publication Number: US-11019965-B2

Title: Bathtub drain flange assembly

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/593,893 filed Dec. 2, 2017, which is incorporated by reference. This application is related to U.S. patent application Ser. No. 15/584,032 filed May 2, 2017, and published under Pub. No. 2017/0314245 A1 and Ser. No. 15/913,452 filed Mar. 6, 2018, and published under Pub. No. 2018/0263426 A1, each of which is incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This present invention pertains to a bathtub drain system and more particularly to a drain flange, which is a short piece of pipe that extends through a drain opening and has a flange that is visible in the bottom of a bathtub. 
     2. Description of the Related Art 
     Water drains from a bathtub through a bathtub drain system or assembly. The bathtub has a drain opening. The drain system includes an L-shaped drain pipe, which is sometimes referred to as a bathtub drain shoe and which includes a 90-degree elbow that has female threads on one end and a length of drain pipe on the other end. The female threads of the elbow is placed below the drain opening. A short piece of pipe that has male threads on a lower end and a radially-extending flange on the upper end is referred to as a drain body or a drain basket or a drain flange. The lower end of the drain flange is passed through the drain opening in the bathtub, and the flange end remains above and surrounds the drain opening. Plumber&#39;s putty can be used around the underside of the flange to provide a seal against the bathtub. The male threads are screwed into the female threads of the elbow to provide a drainage flow path. A washer or a gasket may be used around the male threads adjacent to the underside of the bathtub. The elbow may have a radially-extending flange that presses against the washer or gasket or underside of the bathtub as the male threads of the drain body are screwed into the female threads of the elbow. 
     The lower end of the drain flange typically has a support structure inside that includes a threaded opening. The bathtub drain system generally includes a drain stopper or a strainer or a drain cover that is screwed into the threaded opening in the support structure inside the drain flange. The related U.S. Patent Application Pub. Nos. 2017/0314245 A1 and 2018/0263426 A1 provide examples of drain stoppers, strainers and drain covers. 
     Various manufacturers make and sell bathtub drain systems. There is no single standard size for the threaded opening in the support structure in the drain flange. Each manufacturer makes and sells a bathtub drain system that includes a drain flange that has a threaded opening that is one of several different sizes. A new bathtub drain system from a manufacturer may include or have available a stopper or a strainer or a cover that fits the threaded opening. However, there is often a problem with a mismatch between the size of threads on a plumbing device such as a stopper, strainer or cover and the size of the threaded opening in the support structure in the drain flange, particularly with retrofitting an older drain flange with a newer drain stopper, strainer, drain cover or the like. 
     SUMMARY OF THE INVENTION 
     The present invention solves the problem of a mismatch between the size of threads on a plumbing device and the size of the threaded opening in the support structure in the drain flange by providing a drain flange that has an oversized threaded opening in the support structure and a reducing bushing that fits properly in the oversized threaded opening and has a threaded bore that is one of the several standard sizes for bathtub plumbing devices such as drain stoppers, drain guards, drain covers and drain strainers. 
     A bathtub drain flange assembly is provided that includes: (1) a bathtub drain flange that comprises: (i) a tube having upper and lower ends and inner and outer surfaces; (ii) a flange extending radially outwardly from the upper end; (iii) male threads on the outer surface; and (iv) a support structure in the lower end attached to or formed integral with the inner surface, where the support structure defines an opening, which preferably has female threads; and (2) a reducing bushing received in the opening, where the reducing bushing has an inside surface and an outside surface, where the outside surface is engaged with the support structure, where the inside surface defines a longitudinal bore, and where the inside surface has female threads for receiving a plumbing device such as a drain stopper, a strainer or a drain cover. The reducing bushing can be threaded into opening in the support structure or can be engaged with the support structure by a friction fit or an interference fit for a friction-based engagement. The support structure preferably has a strengthening or reinforcement ring that increases the length of the opening, which preferably extends outside the drain flange rather than inside an inner space defined by the support structure and the inner surface of the tube. A bathtub drain flange kit is also provided that includes a drain flange with an oversized opening, which may or may not be threaded, and two or more reducing bushings, where each reducing bushing provides one of the several different standard sizes for holes that have female threads for receiving plumbing devices that have male threads, which are typically received in a bathtub drain flange fitting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A better understanding of the invention can be obtained when the detailed description of exemplary embodiments set forth below is considered in conjunction with the attached drawings, which can be described as follows. 
         FIG. 1  is a side elevation in partial cross-section of a bathtub fitted with a bathtub drain system, according to the present invention. 
         FIG. 2  is a perspective view of a bathtub drain flange, according to the present invention. 
         FIG. 3  is a side elevation in partial cross-section of a bathtub drain flange assembly installed in a bathtub drain shoe, according to the present invention. 
         FIG. 4  is a side elevation in partial cross-section of a bathtub drain flange assembly, according to the present invention. 
         FIG. 5  is a side elevation in cross-section of a threaded reducing bushing that can be part of bathtub drain flange kit, according to the present invention. 
         FIG. 6  is a side elevation in cross-section of a threaded reducing bushing that can be part of bathtub drain flange kit, according to the present invention. 
         FIG. 7  is a side elevation of a press-fit reducing bushing that can be part of bathtub drain flange kit, according to the present invention. 
         FIG. 8  is a top plan view of the reducing bushing of  FIG. 7 . 
         FIG. 9  is a cross-section of the reducing bushing of  FIG. 8 , as seen along the line  9 - 9 . 
         FIG. 10  is a side elevation in partial cross-section of a bathtub drain flange assembly, according to the present invention, in which a drain stopper and strainer assembly is installed. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
       FIG. 1  is a side elevation in partial cross-section of a bathtub drain flange fitting  10  in a threaded engagement with a bathtub drain shoe  12  that comprises a 90-degree elbow  14  formed integral with or attached to a drain pipe  16 . A partial view in cross-section of a bathtub  18  shows a drain opening  18   a .  FIG. 2  is a perspective view of bathtub drain flange fitting  10 , which comprises a tube or short piece of pipe  10   a  that has male threads  10   b  and a radially-extending flange  10   c  on an upper end  10   d  of the tube  10   a . Tube  10   a  has an opposing lower end  10   e  and an inner surface  10   f  that defines a cylindrical drainage flow path. A support structure  10   g  at the lower end  10   e  is engaged with or fastened to the inner surface  10   f  or is formed integral with tube  10   a . Support structure  10   g  has a threaded opening  10   h  that is defined by female threads  10   i , which is in the center of the drainage flow path. Support structure  10   g  is illustrated as a pair of orthogonal crossbars, but can be any structure that provides the threaded opening  10   h  and that does not substantially block the drainage flow path. Further, a drain flange typically has a threaded opening such as threaded opening  10   h ; however, threads are not required for the present invention, which is discussed in some detail below. 
     The lower end  10   e  of the bathtub drain flange fitting  10  is passed through the drain opening  18   a  in the bathtub  18  and sealed against an upper surface of the bathtub  18  by plumber&#39;s putty or a gasket (not shown). Elbow  14  has a flanged upper end  14   a , which has female threads  14   b . A gasket or a sealing ring (not shown) is typically placed between the flanged upper end  14   a  of the elbow and the underside of the bathtub  18 . The bathtub drain flange fitting  10  is screwed into the elbow  14 . The male threads  10   b  on the tube  10   a  matingly engage the female threads  14   b  in the flanged upper end  14   a  of the elbow  14  of the bathtub drain shoe  12 , thereby providing a drainage flow path for draining water out of the bathtub  18 . A drain stopper  20  has a cap  20   a  on an upper end and male threads on an opposing lower end  20   b . The threaded lower end  20   b  of the drain stopper  20  is received in threaded opening  10   h  in a threaded engagement with the support structure  10   g . Related application Pub. No. 2017/0314245 A1 provides additional information on bathtub drain stoppers. 
       FIG. 3  is a side elevation in partial cross-section of a bathtub drain flange fitting  30  in a threaded engagement with the elbow  14  of the bathtub drain shoe  12  for sealing and providing a drainage flow path from a bathtub  28 , which has a drain opening  28   a . Drain flange fitting  30  comprises a tube or short piece of pipe  30   a  that has male threads  30   b  and a radially-extending flange  30   c  on an upper end  30   d  of the tube  30   a . Tube  30   a  has an opposing lower end  30   e  and an inner surface  30   f  that defines a cylindrical drainage flow path. A support structure  30   g  at the lower end  30   e  is engaged with or fastened to the inner surface  30   f  or is formed integral with tube  30   a . Support structure  30   g  has a threaded opening  30   h  that is defined by female threads  30   i , which is in the center of the drainage flow path. Support structure  30   g  has a tubular extension  30   j  that extends downwardly from the underside of the support structure  30   g . Tubular extension  30   j  has a central opening defined by female threads that is coaxial with and the same size as opening  30   h , so the combined opening is referred to as opening  30   h , and the combined threads are referred to as female threads  30   i.    
     Support structure  30   g  can be any structure that provides the threaded opening  30   h  and that does not substantially block the drainage flow path. Support structure  30   g  preferably comprises a pair of crossbars that are orthogonal to one another and that have longitudinal axes that intersect at about the center of the drainage flow path. The support structure  30   g  includes a centralized ring, and the crossbars extend between an outer portion of the ring and the inner surface  30   f  of the tube  30   a . Tubular extension  30   j  functions as a strengthening and reinforcement ring for providing a strong anchor point for attaching, directly or indirectly, a plumbing device such as a drain stopper to the support structure  30   g . Tubular extension or reinforcement ring  30   j  extends longitudinally beyond and below the lower end  30   e  of tube  30   a . The crossbars or an equivalent can be referred to as wall anchors that hold and support a ring, where preferably, the ring is thicker that the wall anchors. The wall anchors preferably have a lower surface that is coincident with the lower end  30   e  of the tube  30   a , while the ring has an upper end that is coincident with the upper surface of the wall anchors and a lower end that extends below the lower surface of the wall anchors and below the lower end  30   e  of the tube  30   a . The ring has a bore or opening  30   h  that is defined by the female threads  30   i.    
     The threaded opening  30   h  has an inside diameter that is greater than the inside diameter of presently commercially available drain flanges. The purpose of this greater diameter is to be able to adapt the inside diameter of the threaded opening in the drain flange to the outside diameter of a drain stopper, strainer or drain cover that is to be received in the drain flange. A threaded tubular reducing bushing  40  is screwed into the threaded opening  30   h , which reduces the size of the threaded opening in the drain flange to accommodate various stoppers, strainers and drain covers. 
     Plumbing devices, such as stoppers, strainers and drain covers, that screw into the threaded opening in a drain flange come in a number of different sizes, including ⅜, 5/16 and ¼ inch diameters and with 10-24 machine threads (size 10 with 24 threads per inch). Prior art drain flanges also have a threaded opening, which may have any one of these sizes or another size. It has been a problem to find a desired plumbing device of the right size for a previously-installed drain flange or even for a new drain flange if the desired plumbing device is from a manufacturer other than the one that made the drain flange. The present invention solves this problem by providing a drain flange with an oversized or larger-than-normal threaded opening, which can be reduced in size or diameter by a reducing bushing to provide a desired inside diameter of a threaded opening for a desired plumbing device, such as a drain stopper with or without a strainer, a stand-alone drain strainer or perforated drain cover or a decorative standoff drain cover such as one that hides the drain flange. The oversized or larger-than-normal threaded opening for the drain flange of the present invention may be ½, ⅝ or ¾ inch or any suitable or desirable size including metric sizes. 
     In  FIG. 3 , the reducing bushing  40  is screwed into the threaded opening  30   h  and has its own threaded bore  40   e , which has a smaller inside diameter than the threaded opening  30   h . A drain stopper  36  has a cap  36   a  and a threaded lower end  36   b , which is screwed into the threaded bore  40   e  in the reducing bushing  40 . The reducing bushing  40  adapts the size of the threaded opening  30   h  by providing the threaded bore  40   e , which fits or matingly accommodates the threaded end  36   b  of the drain stopper  36 . 
       FIG. 4  is a side elevation in partial cross-section of the bathtub drain flange fitting  30  of  FIG. 3 .  FIG. 4  shows that the threaded reducing bushing  40  can be screwed into the bottom of the tubular extension  30   j  rather than into the top as was shown in  FIG. 3 . Placing the reducing bushing  40  on the underside of the drain flange  30  rather than on the topside provides additional flexibility and another option for accommodating a plumbing device. Some thought is required to ensure that as a plumbing device is threaded into the reducing bushing  40 , the reducing bushing tightens into the threaded opening  30   h  rather than unscrewing from the threaded opening  30   h . It may be desirable to use a reverse thread pattern. 
       FIG. 5  is a side elevation in cross-section of a threaded tubular reducing bushing  50 , which comprises a hollow cylindrical tube that has an upper end  50   a , an opposing lower end  50   b , a central longitudinal bore  50   c , a radially-extending flange  50   d  on the upper end  50   a , female threads  50   e  that define the bore  50   c  in the flanged upper end  50   a  and male threads  50   f  on an outside surface of the tube  50   a  between an underside of the flange  50   d  and the lower end  50   b . Reducer bushing  50  does not have threads defining the bore  50   c  between an underside of the flange  50   d  and the lower end  50   b , although it could. The reducing bushing  50  has an inside diameter d 1  of the bore  50   c  where the bore  50   c  is defined by female threads and an inside diameter d 2  of the bore  50   c , where the bore is defined by a smooth wall that does not have female threads. The threaded inside diameter d 1  is smaller than the smooth-wall inside diameter d 2 . The radially-extending flange  50   d  can have a hexagonal head for receiving a socket wrench and can be referred to as a grip head. 
       FIG. 6  is a side elevation in cross-section of a threaded tubular reducing bushing  60 , which is identical to the reducing bushing  50  in  FIG. 5 , except for having a threaded bore  60   e  that has a diameter d 3  that is different from the diameter d 1  of the threaded bore  50   e  in the reducing bushing  50  in  FIG. 5 . The diameters d 1  and d 3  are preferably two of the common diameters of plumbing devices that are used in bathtub drain flanges, such as 5/16 and ¼ inch. Reducing bushing  40  in  FIGS. 3 and 4  may have an inside diameter of its threaded bore  40   e  of ⅜ inch for accommodating the largest of the common sizes of male threaded ends on plumbing devices that get screwed into a drain flange in a bathtub. These sizes are, of course, provided for the purpose of illustration, and one should choose sizes that are appropriate for the anticipated applications. A bathtub drain flange kit preferably includes a plurality of reducing bushings that each have a male end of a size that fits properly in the threaded opening in the drain flange, where each reducing bushing has a different size threaded hole, and where each threaded hole corresponds to one of the standard sizes for bathtub plumbing devices that are typically received in a bathtub drain flange. 
       FIG. 7  is a side elevation of a press-fit reducing bushing  70 .  FIG. 8  is a top plan view of the reducing bushing  70 .  FIG. 9  is a cross-section of the reducing bushing  70  of  FIG. 8 , as seen along the line  9 - 9 . Similar to the reducing bushing  50  in  FIG. 5 , reducing bushing  70  comprises a hollow cylindrical tube that has an upper end  70   a , an opposing lower end  70   b , a central longitudinal bore  70   c , a radially extending flange  70   d  on the upper end  70   a  and female threads  70   e  that define the bore  70   c  in the flanged upper end  70   a . Rather than having male threads to threadedly engage the threaded opening in a drain flange, the press-fit reducing bushing  70  has a plurality of cantilever springs  70   k  around the circumference of the tube. A cantilever spring is similar to a diving board for a swimming pool, where one end of the diving board is fixed in place and the other end is free to move up and down. The cantilever springs  70   k  have one end fixed to a ring or band  70   m  as shown in  FIG. 9 , and the other end of each spring  70   k  is not fixed and is free. The springs  70   k  are oriented longitudinally with respect to the longitudinal axis of the reducing bushing  70 . A center portion of each spring  70   k  is curved radially outwardly. With reference to  FIG. 9 , end  70   b  of the reducing bushing  70  has a circumferential groove  70   n  in which the band  70   m  is received. The band  70   m  has a bead that fits in the groove  70   n  and a straight portion adjacent to the bead that lies against or abuts the outside surface of the tubular wall of the bushing  70 . Various detent mechanisms can be used as an alternative to the cantilever springs  70   k , which is particularly easy if the reducing bushing  70  is made of a plastic material that will deform and then regain its shape. For example, with reference to  FIG. 5 , the threads  50   f  can be replaced with a plurality of rings that are similar to threads, except parallel to one another and oriented orthogonal to the longitudinal axis of the reducing bushing. Threads spiral while the parallel rings do not. The rings can have a triangular cross-section and be arranged to easily deform as they are pushed into the threaded opening in the drain flange, but catch on the threads  30   i  to inhibit disengagement from the support structure  30   g.    
       FIG. 10  is a side elevation in partial cross-section of the bathtub  28  and bathtub drain flange fitting  30  of  FIG. 3 . The drain flange  30  in  FIG. 10  is the same as the drain flange  30  in  FIG. 3 . However, the press-fit reducing bushing  70  of  FIGS. 7-9  is received in the threaded opening  30   h . The press-fit reducing bushing  70  is not screwed into the threaded opening  30   h ; rather, bushing  70  is pressed into threaded opening  30   h . The cantilever springs flatten or straighten out to some extent and press radially outwardly against the female threads that define the opening  30   h , thereby providing friction between the reducing bushing  70  and the support structure  30   g  in the drain flange  30 . It is this friction-based engagement that holds the reducing bushing  70  in the drain flange  30 . This friction-based engagement is referred to as a press fit or an interference fit. The alternative detent mechanisms also rely on friction-based engagement. Since the engagement between the reducing bushing  70  and the drain flange  30  is based on the friction of a press fit or interference fit, it is not necessary for opening  30   h  in the support structure  30   g  to be threaded or to have female threads. Reducing bushing  70  can fit tightly and securely in an opening that is defined by a smooth or rough wall. A particularly good structure for the wall of the opening may be parallel rings of thread-like ridges that have a cross-section of a right triangle facing in a manner to make it easier to push a reducing bushing in than to pull the reducing bushing out of the opening  30   h  in the support structure  30   g.    
     A drain stopper  80  has a cap  80   a  and a male-threaded lower end  80   b , which is in a threaded engagement with the female threads  70   e  that define the bore  70   c  in the reducing bushing  70 . Drain stopper  80  is engaged with the reducing bushing  70  by threads, but the reducing bushing  70  is engaged with the drain flange  30  by friction between the plurality of cantilever springs  70   k  and the female threads  30   i  that define the threaded opening  30   h  in the drain flange  30 . Drain stopper  80  has an elongate open-close mechanism  80   c  and a seal  80   d . A strainer  82  surrounds the open-close mechanism  80   c  and is in the drainage flow path so that any hair, debris or object tends to be caught and held in or on the strainer  82 . Since the drain stopper  80  is in a press-fit or friction engagement with the drain flange  30  through the reducing bushing  70 , drain stopper  70  can be simply pulled out of the drain flange  30  to clean the strainer  82 . 
     As has been stated above, there has often been a mismatch between the inside diameter of a threaded opening in a drain flange fitting in a bathtub drain system and the outside diameter of a plumbing device that one wishes to place in the drain flange. The present invention provides a drain flange that has an oversized or larger-than-normal threaded opening and at least one reducing bushing that fits properly in the threaded opening and fastens or attaches the reducing bushing to the drain flange, where the reducing bushing provides one of a number of standard sizes for a threaded opening for receiving and holding a plumbing device such as a drain stopper. In addition to this bathtub drain flange assembly, which includes at least one reducing bushing, the present invention provides a bathtub drain flange kit that includes at least two reducing bushings and preferably a reducing bushing for each of the several standard sizes for plumbing devices that are received and held in a bathtub drain flange. The reducing bushings function as adapters for connecting a plumbing device to a drain flange where otherwise there is a mismatch between the size of the threaded opening in the drain flange and the size of a threaded end on the plumbing device that is meant to connect to the drain flange. The bathtub drain flange kit preferably includes a reducing bushing for each of the standard 10-24 machine thread and ⅜, 5/16 and ¼ inch diameter male-threaded ends of typical bathtub plumbing devices. While a reducing bushing is typically engaged with a drain flange using a threaded engagement, threads are not the only means for engagement. The support structure in the drain flange can have an opening that is not threaded, and the reducing bushing can engage the drain flange using a press fit or an interference fit. 
     Having described the invention above, various modifications of the techniques, procedures, materials, and equipment will be apparent to those skilled in the art. It is intended that all such variations within the scope and spirit of the invention be included within the scope of the appended claims.